DE102013211900B4 - Piston valve and valve piston for a piston valve - Google Patents

Abstract

Piston valve (1), with a valve piston (3) which is received in a guide (2) and is displaceable relative to the guide (2), and which controls or regulates a flow of a medium through the piston valve (1) depending on its switching position, wherein the valve piston (3) is designed as a hollow component through which the medium can flow, having a sleeve-like wall (4) and an end wall (5), wherein at least one recess (6) is made in the sleeve-like wall (4), which is closed in a first switching position of the valve piston (3) and open in a second switching position of the valve piston (3), characterized in that at least one control orifice (18) is made in the end wall (5), which is open independently of the switching position of the valve piston (3), wherein the or each control orifice (18) has a relatively small flow cross-section relative to the or each recess (6).

Description

The invention relates to a piston valve according to the preamble of claim 1. Furthermore, the invention relates to a valve piston for a piston valve and a hydrodynamic brake of a motor vehicle with such a piston valve.

In a variety of automotive applications, the flow of a medium, such as hydraulic oil, must be controlled or regulated. In a hydrodynamic brake or flow brake, depending on the oil pump capacity, either the hydraulic oil pressure and flow rate provided by the retarder must be supported by draining an oil reservoir, or, if the oil pump capacity can provide a sufficiently high hydraulic oil pressure and flow rate on its own, the oil reservoir must be additionally filled. Valves are used to control or regulate the flow of a medium.

A valve designed as a piston valve has a valve piston as the valve body, which controls or regulates the flow of the medium through the piston valve depending on its switching position. Particularly when such a piston valve is used to control or regulate the flow of a medium through lines with large flow cross-sections, the valve piston also has large dimensions and, according to the state of the art, a relatively high weight and thus a high inertia. Such piston valves then have relatively poor response characteristics, since the inertia of the valve piston must be overcome when transferring it between its switching positions.

The DE 10 2007 047 902 A1 discloses a piston valve with a guide body consisting of two partial bodies, in which a valve piston can be displaced against the spring force of a spring element. Depending on the switching position of the valve piston, the flow of a medium is controlled or regulated by the guide of the piston valve.

The DE 27 36 076 A1 discloses a non-return valve with damping device for liquid lines.

The DE 103 50 022 A1 discloses an engine braking system for a multi-cylinder engine.

The DE 10 2007 033 146 A1 discloses an adjustment valve for adjusting the delivery volume of a positive displacement pump.

The US 2001 / 0 027 773 A1 discloses an engine braking system for generating a decompression valve event in an internal combustion engine.

The US 2 918 083 A discloses a check valve adapted for use in low and high pressure fluid lines.

The US 2 206 356 A discloses a check valve arranged in a pipeline.

Based on this, the present invention is based on the object of creating a novel piston valve and a valve piston for a piston valve as well as a hydrodynamic brake with such a piston valve.

This object is achieved by an object according to patent claim 1. According to the invention, the valve piston is designed as a hollow component through which the medium can flow, having a sleeve-like wall and an end wall, wherein at least one recess is introduced into the sleeve-like wall, which recess is closed in a first switching position of the valve piston and is open in a second switching position of the valve piston.

Because the valve piston in the piston valve according to the invention is designed as a hollow component through which the medium to be controlled or regulated flows, the valve piston, even with large dimensions, has a relatively low weight and thus a relatively low mass inertia. This largely eliminates the delays in the response behavior of the piston valve known from practice. At least one recess is formed in the sleeve-like wall of the valve piston, which is designed as a hollow component. This recess is closed in the first switching position of the valve piston and open in the second switching position of the valve piston.

Preferably, an outer surface of the sleeve-like wall interacts with a corresponding sealing surface of the guide in such a way that in the first switching position of the valve piston, the sealing surface of the guide closes the or each recess in the sleeve-like wall, and in the second switching position of the valve piston, the sealing surface of the guide releases the or each recess in the sleeve-like wall. The sealing function in the first switching position of the valve piston is therefore provided by the interaction between the sealing surface of the guide and the outer surface of the sleeve-like wall of the valve piston, wherein the sealing surface of the guide covers the or each recess in the sleeve-like wall of the valve piston in the first switching position of the valve piston. Preferably, A tight clearance fit is formed or set between the sealing surface of the guide and the outer surface of the sleeve-like wall of the valve piston.

According to a further development, the valve piston has a radially outwardly directed collar at an end opposite the end wall. According to a first variant, a spring element is supported on the collar, which presses the valve piston into the first switching position. According to a second variant, a thread is formed on the collar, which a servomotor engages to adjust the valve piston between its switching positions. This can increase functional integration. The collar can be provided with recesses to optimize function and/or weight.

At least one control orifice is incorporated into the end wall, which is open regardless of the switching position of the valve piston, wherein the or each control orifice has a relatively small flow cross-section relative to the or each recess. A piston valve with such a valve piston is preferably designed as a shuttle valve, which in the first switching position allows a relatively small flow in a first flow direction through the or each control orifice and in the second switching position allows a relatively large flow in a second flow direction opposite to the first flow direction through the or each recess. The design of the piston valve according to the invention as a shuttle valve with at least one control orifice in the end wall of the valve piston is preferred. Such a shuttle valve is advantageously suitable for use in a hydrodynamic brake of a motor vehicle.

Preferably, several recesses are provided in the sleeve-like wall, evenly distributed around the circumference of the sleeve-like wall. This allows the flow through the valve piston to be optimally adjusted in its second switching position.

The hydrodynamic brake according to the invention is defined in claim 8.

• 1 eine schematisierte perspektivische Ansicht eines ersten erfindungsgemäßen Kolbenventils in einer ersten Schaltstellung desselben;
• 2 einen Querschnitt durch 1;
• 3 eine schematisierte perspektivische Ansicht des Kolbenventils der 1 in einer zweiten Schaltstellung desselben;
• 4 einen Querschnitt durch 3;
• 5 einen Ventilkolben des Kolbenventils der 1 bis 4 in Alleindarstellung;
• 6 einen alternativen Ventilkolben des Kolbenventils in Alleindarstellung;
• 7 eine schematisierte perspektivische Ansicht eines zweiten erfindungsgemäßen Kolbenventils in einer ersten Schaltstellung desselben;
• 8 einen Querschnitt durch 7;
• 9 eine schematisierte perspektivische Ansicht eines dritten erfindungsgemäßen Kolbenventils in einer ersten Schaltstellung desselben;
• 10 einen Querschnitt durch 9;
• 11 eine schematisierte perspektivische Ansicht eines vierten erfindungsgemäßen Kolbenventils in einer ersten Schaltstellung desselben;
• 12 einen Querschnitt durch 11;
• 13 eine schematisierte perspektivische Ansicht eines fünften erfindungsgemäßen Kolbenventils in einer ersten Schaltstellung desselben bei Verwendung desselben im Zusammenhang mit einer hydrodynamische Bremse;
• 14 eine schematisierte perspektivische Ansicht des Kolbenventils der 13 in einer zweiten Schaltstellung desselben; und
• 15 einen Ventilkolben des Kolbenventils der 13 und 14 in Alleindarstellung.

Preferred developments of the invention will become apparent from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail, without being limited thereto, with reference to the drawings. Herein:

• 1 a schematic perspective view of a first piston valve according to the invention in a first switching position thereof;
• 2 a cross-section through 1 ;
• 3 a schematic perspective view of the piston valve of the 1 in a second switching position thereof;
• 4 a cross-section through 3 ;
• 5 a valve piston of the piston valve of the 1 to 4 in sole representation;
• 6 an alternative valve piston of the piston valve in a single view;
• 7 a schematic perspective view of a second piston valve according to the invention in a first switching position thereof;
• 8 a cross-section through 7 ;
• 9 a schematic perspective view of a third piston valve according to the invention in a first switching position thereof;
• 10 a cross-section through 9 ;
• 11 a schematic perspective view of a fourth piston valve according to the invention in a first switching position thereof;
• 12 a cross-section through 11 ;
• 13 a schematic perspective view of a fifth piston valve according to the invention in a first switching position thereof when used in connection with a hydrodynamic brake;
• 14 a schematic perspective view of the piston valve of the 13 in a second switching position thereof; and
• 15 a valve piston of the piston valve of the 13 and 14 in sole representation.

1 to 4 show different schematic views of a piston valve 1 according to the invention according to a first embodiment of the invention, wherein 1 and 2 the piston valve 1 in a first switching position and 3 and 4 show the piston valve 1 in a second switching position.

The piston valve 1 according to the invention has a guide 2, which can be, for example, a housing of the piston valve 1, wherein a valve piston 3 is accommodated in the guide 2 of the piston valve 1 and is displaceable relative to the guide 2 in order to transfer the valve piston 3 and thus ultimately the piston valve 1 between its different switching positions by displacing the valve piston 3 relative to the guide 2. Depending on the switching position of the valve piston 3 in the guide 2 It regulates or controls the flow of a medium, for example a flow of hydraulic oil, through the piston valve 1. In 5 is the valve piston 3 of the piston valve 1 of the 1 to 4 shown in isolation.

The valve piston 3 of the piston valve 1 is designed as a hollow component through which the medium to be controlled or regulated can flow, having a sleeve-like wall 4 and an end wall 5. At least one recess 6 is made in the sleeve-like wall 4, which in the first switching position of the valve piston 3 (see 1 and 2 ) is closed, and in the second switching position of the valve piston 3 (see 3 and 4 ) is open. In the illustrated embodiment, several recesses 6 are made in the sleeve-like wall 4 of the valve piston 3, which are evenly distributed around the circumference of the sleeve-like wall 4 in order to open the second switching position of the valve piston 3 (see 3 and 4 ) to enable optimal flow through the valve piston 3, which is designed as a hollow component.

In the example of 1 to 5 The recesses 6 in the sleeve-like wall 4 of the valve piston 3 are each designed as circular recesses. Other geometric contours of the recesses 6 can also be used.

How 2 to 4 can be removed, an outer surface 7 of the sleeve-like wall 4 of the valve piston 3 interacts with a corresponding sealing surface 8 of the guide 2 in such a way that in the first switching position of the valve piston 3 (see 1 , 2 ) the sealing surface 8 of the guide 2 closes or covers the or each recess 6 in the sleeve-like wall 4 of the valve piston 3, whereas in the second switching position of the valve piston 3 (see 3 , 4 ) the sealing surface 8 of the guide 2 releases the or each recess 6 of the sleeve-like wall 4 of the valve piston 3.

In the 1 to 4 The piston valve 1 shown is a pressure-controlled piston valve.

Then, if as in 2 shown, the pressure Px on a first side of the valve piston 3 is greater than the pressure Py on a second side of the valve piston 3, the valve piston 3 is pressed against a stop 9 on the basis of this pressure gradient, wherein the valve piston 3 then 1 and 2 shown first switching position, in which the recesses 6 are closed.

Then, however, if the pressure Py is 4 greater than the pressure Px, the valve piston 3 is moved from the 2 shown first switching position into the one shown 4 shown second switching position, whereby the recesses 6 in the sleeve-like wall 4 of the valve piston 3 are then released. In the switching position of the 4 the valve piston 3 is lifted from the stop 9.

How 1 to 4 can be removed, a radially outwardly directed collar 10 is formed on one end of the valve piston 3 opposite the front side 5, which on the one hand in the first switching position of the 1 and 2 and on the other hand in the second switching position of the 3 and 4 defines the relative position of the valve piston 3 to the guide 2. Thus, in the first switching position, the 1 and 2 the collar 10 against the stop 9, whereas in the switching position the 3 and 4 the collar 10 comes to rest on a stop 11 provided by the guide 2.

As already explained, the valve piston 3 of the piston valve 1 is designed as a hollow component through which the medium to be controlled or regulated flows at least in the second switching position of the valve piston 3 or piston valve 1.

Such a hollow component can be produced cost-effectively as a deep-drawn component.

Such a hollow component has a low weight and thus a low mass inertia, so that the piston valve 1 according to the invention has a good response behavior.

The design of the piston valve 1 according to the invention is simple and compact.

The flow of the medium through the piston valve 1 is not impeded in the second switching position of the valve piston 3.

A second embodiment of a piston valve 1 according to the invention is shown 7 and 8 , where the embodiment of the 7 and 8 from the embodiment of the 1 to 4 only differs in that in the example the 7 and 8 In addition, a spring element 12 is provided, which is supported on the one hand on the collar 10 of the valve sleeve 3 and on the other hand on the stop 11 of the guide 2. The spring element 12 presses the valve piston 3 into the 1 and 2 shown first switching position against the stop 9. To transfer the piston valve 1 of the 7 and 8 into a second switching position, the spring force provided by the spring element 12 must be overcome.

A further embodiment of a piston valve 1 according to the invention with a spring element 12, the spring force of which pushes the valve piston 3 into the first switch position is in 9 and 10 While in the example the 7 and 8 the valve piston 3 is guided in a bore of the guide 2, is in 9 and 10 the valve piston 3 is guided on a projection 13 of the guide 2.

However, with regard to the design of the valve piston 3, the embodiment of the 7 and 8 and the embodiment of the 9 and 10 with the examples of 1 to 4 so that reference can be made to the above statements.

A further embodiment of a piston valve 1 according to the invention is shown 11 and 12 . In 11 and 12 a thread 14 is formed on the collar 10 of the valve piston 3, to which a servo motor 15 engages via a shaft 17 carrying a counter thread 16 in order to move the valve piston 3 of the piston valve 1 of the embodiment of the 11 and 12 controlled or regulated by means of the servo motor 15 between its switching positions. In the embodiment of the 11 and 12 is applied to the spring element 12 of the embodiments of the 7 , 8 and the 9 , 10 omitted. Stop 9 can also be omitted.

However, with regard to the design of the valve piston 3, the embodiment of the 11 and 12 with the embodiment of the 1 to 4 agree, so reference is made to the above comments. 6 shows the valve piston 3 of the embodiment of the 11 and 12 in sole representation.

A further piston valve 1 with a valve piston 3 designed according to the invention is shown in the embodiment of 13 to 15 shown, where the embodiment of the 13 to 15 essentially differs from the embodiments described above in that, on the one hand, the recesses 6 in the sleeve-like wall 4 of the valve piston 3 are not circular in cross-section, but rather elongated or oval, and that, in addition, recesses are also made in the end wall 5 of the valve piston 3, namely two control orifices 18 in the embodiment shown. The collar 10 of the valve piston 3 is provided with recesses 23 here.

Then, if such control orifices 18 are introduced into the end wall 5 of the valve piston 3, the piston valve 1 according to the invention is a so-called shuttle valve, which in the first switching position (see 13 ) a relatively small flow exclusively through the or each control orifice 18 in a first flow direction and in the second switching position (see 14 ) allows a relatively large flow in a second flow direction opposite to the first flow direction additionally through the or each recess 6. The control orifices 18 therefore have a relatively small flow cross-section, both individually and in total, compared to the recesses 6.

13 and 14 show a piston valve 1 designed as a shuttle valve in the preferred application in a hydrodynamic brake of a motor vehicle, wherein according to 13 and 14 the guide 2 of the valve piston 1 is provided by a nozzle 19 of an oil reservoir 20 of the hydrodynamic brake, wherein the oil reservoir 20 is connected via the shuttle valve 1 to a hydraulic control circuit 21 of the hydrodynamic brake via a flow pipe 22.

Then, when a retarder (not shown) of the hydrodynamic brake is running and the oil pump output alone can provide a sufficiently high hydraulic pressure in the hydraulic control circuit 21 of the hydrodynamic brake, the shuttle valve 1 takes the 13 shown first switching position 1, in which the recesses 6 in the sleeve-like wall 4 of the valve piston 3 are closed, whereby the oil reservoir 20 can then be filled from the hydraulic control circuit 21 via the control orifices 18 in the end wall 5 of the valve piston 3. 13 The flow arrows shown visualize the filling of the oil reservoir 20 starting from the hydraulic control circuit 21 via the control orifices 18.

However, when the retarder is switched on and the oil pump output cannot yet provide sufficient hydraulic pressure and oil volume flow in the hydraulic control circuit 21 of the hydrodynamic brake during start-up or acceleration, the retarder can be supported in providing the hydraulic pressure and oil volume flow for the hydraulic control circuit 21 by emptying the oil reservoir 20, whereby the shuttle valve 1 then 14 shown second switching position, in order to then empty the oil reservoir 20 into the hydraulic control circuit 21, namely via the recesses 6 in the sleeve-like wall 4 of the control piston 3.

What all embodiments have in common is that a valve piston 3 designed as a hollow component is used, through which the medium to be controlled or regulated flows in at least one switching position of the piston valve 1.

This valve piston 3 can be easily and inexpensively manufactured from sheet metal using a deep-drawing process and is lightweight. Therefore, a piston valve 1 can be produced with simple safe, compact design and good responsiveness.

Due to a relatively tight clearance fit between the sleeve-like wall 4 of the valve piston 3 and the guide 2 for the valve piston 3, the sealing function for the recesses 6 can be easily adjusted in the first switching position.

Then, if control orifices 18 are additionally incorporated in the end wall 5 of the valve piston 3, a shuttle valve can be provided.

Then, when the piston valve 1 assumes the second switching position in which the recesses 6 in the sleeve-like wall 4 of the valve piston 3 are released, the flow through the piston valve 1, in particular the valve piston 3 thereof, is not impeded.

Reference symbol

1

Piston valve

2

guide

3

valve piston

4

sleeve-like wall

5

front wall

6

recess

7

lateral surface

8

Sealing surface

9

stop

10

collar

11

stop

12

spring element

13

projection

14

thread

15

actuator

16

Counter thread

17

Wave

18

Control panel

19

Support

20

Oil storage

21

hydraulic control circuit

22

flow tube

23

recesses

Claims (8)

Piston valve (1), with a valve piston (3) which is received in a guide (2) and is displaceable relative to the guide (2), and which controls or regulates a flow of a medium through the piston valve (1) depending on its switching position, wherein the valve piston (3) is designed as a hollow component through which the medium can flow, having a sleeve-like wall (4) and an end wall (5), wherein at least one recess (6) is made in the sleeve-like wall (4), which is closed in a first switching position of the valve piston (3) and open in a second switching position of the valve piston (3), characterized in that at least one control orifice (18) is made in the end wall (5), which is open independently of the switching position of the valve piston (3), wherein the or each control orifice (18) has a relatively small flow cross-section with respect to the or each recess (6). Piston valve (1) after Claim 1 , characterized in that an outer circumferential surface (7) of the sleeve-like wall (4) interacts with a corresponding sealing surface (8) of the guide (2) in such a way that in the first switching position of the valve piston (3) the sealing surface (8) of the guide (2) closes the or each recess (6) in the sleeve-like wall (4), and in the second switching position of the valve piston (3) the sealing surface (8) of the guide (3) releases the or each recess (6) in the sleeve-like wall (4). Piston valve (1) after Claim 1 or 2 , characterized in that a plurality of recesses (6) are made in the sleeve-like wall (4), which are evenly distributed around the circumference of the sleeve-like wall (4). Piston valve (1) according to one of the Claims 1 until 3 , characterized in that the valve piston (3) has a radially outwardly directed collar (10) at an end opposite the end wall (5). Piston valve (1) after Claim 4 , characterized in that a spring element (12) is supported on the collar (10), which presses the valve piston (3) into the first switching position. Piston valve (1) after Claim 4 , characterized in that a thread (14) is formed on the collar (10), on which a servo motor (15) acts to adjust the valve piston (3) between its switching positions. Piston valve (1) after Claim 1 , characterized in that it is designed as a shuttle valve, which in the first switching position a relatively small flow in a first flow direction through the or each control orifice (18) and, in the second switching position, a relatively large flow in a second flow direction opposite to the first flow direction through the or each recess (6). Hydrodynamic brake of a motor vehicle, with a retarder, an oil reservoir (20), a hydraulic control circuit (21) and a piston valve (1) connected between the oil reservoir (20) and the hydraulic control circuit (21), wherein in a first switching position of the piston valve (1) the oil reservoir (20) can be filled and in a second switching position of the piston valve (1) during or immediately after switching on the retarder the oil reservoir (20) can be emptied to increase the oil volume flow for the retarder, wherein the piston valve (1) according to one of the Claims 1 until 7 is trained.