DE102018202258A1 - Valve assembly with electric motor and energy storage - Google Patents

Abstract

The invention relates to a valve assembly (10) with a movable valve body (20) which is designed such that a free flow cross section of at least one associated fluid flow path (11) is adjustable by movement of the valve body (20), wherein an electric motor (23) is provided , which is coupled to the valve body (20) via a mechanical transmission (22), wherein a position sensor (21) is provided, with which the position of the valve body (20) can be measured. According to the invention, a control device (30) is provided, whose manipulated variable (33) is a current and / or a voltage of the electric motor (23), wherein the actual value (34) is a measured value of the position sensor (21), wherein the control device (30) to an electrical power supply (32) is connectable, wherein is connected to an electrical energy store (31), wherein the control device (30) is arranged so that their setpoint value when the Spannungsversorg ung (32) is interrupted, is set to a predetermined value, wherein the position control is performed using electrical energy from the electrical energy storage (31).

Description

The invention relates to a valve assembly according to the preamble of claim 1.

From the DE 10 2014 224 500 A1 a valve assembly is known in which the valve body designed as a slide is moved by means of an electric motor and a gear transmission. The valve body is biased by a spring in a safe position. The safe position is often a blocking position in which the actuator connected to the valve assembly can not move.

A disadvantage of the known valve assembly is that the electric motor must overcome the force of the spring to move the valve body. He must be designed accordingly powerful. However, this contradicts the requirement that the valve assembly should be designed in the manner of a valve disc, wherein the electric motor is integrated in the valve disc. For this a small electric motor is needed.

Accordingly, the object of the invention is to provide a valve assembly which manages with a small electric motor, wherein in the event of a fault, in particular when the supply voltage is interrupted, it is still ensured that the valve assembly automatically adjusts to a safe state or a safe position ,

According to the independent claim, it is proposed that a control device is provided whose manipulated variable is a current and / or a voltage of the electric motor, wherein the actual value is a measured value of the position sensor, wherein the control device is connectable to an electrical power supply, wherein it is connected to an electrical Energy storage is connected, wherein the control device is set up so that their setpoint value when the power supply is interrupted, is set to a predetermined value, wherein the position control is performed using electrical energy from the electrical energy storage. The predetermined value is preferably chosen so that the higher-level device in which the valve assembly is installed is in a safe state when said position control is completed, i. if the actual value is substantially equal to the setpoint. The manipulated variable can be determined for example by means of a P or a PI controller from the setpoint and the actual value, whereby other controllers are used. The valve assembly is preferably intended for use with a pressurized fluid, which is most preferably a liquid, especially hydraulic oil.

In the dependent claims advantageous refinements and improvements of the invention are given.

It can be provided that the mechanical transmission is designed to be self-locking, that the valve body is movable by the electric motor, but not vice versa. It should be noted that on the valve spool hydraulic flow forces can act. While the valve spool is designed to minimize flow forces acting in the direction of movement, it is usually not possible to completely prevent this. The conventional return spring is typically designed so strong that it can overcome the flow forces occurring in any case. By said self-locking should be prevented in particular that moves the valve body due to the aforementioned flow forces. The mechanical transmission can be designed, for example, as a screw spindle gear or as a gear transmission with a high reduction ratio.

It can be provided that the mechanical transmission is designed without play. This improves the accuracy of the position control. Preferably, a gear is used, in which at least some movable gear elements rest under elastic bias to each other, so that game is avoided. For example, a Wälzkörpergewindetrieb is used, in which the, preferably spherical, rolling elements are installed under bias between the nut and the spindle.

It can be provided that the valve body can be moved to the position corresponding to the predetermined value exclusively by using the electric motor. In particular, no return spring is provided, which biases the valve body in a safe position. The force of the return spring would have to be overcome by the electric motor, so that the electric motor should be designed according to high performance, which should be avoided.

It can be provided that the valve assembly is designed in the manner of a valve disc having a first and a second planar sealing surface, wherein the first and the second sealing surface are arranged parallel to each other, wherein they face away from each other, wherein the entire valve assembly, in particular the electric motor between the two, defined by the first and the second sealing surface levels is arranged. The valve assembly is, for example, according to the DE 10 2014 224 500 A1 formed, wherein the energy storage device according to the invention arranged, for example, in the second cavity is. The in the DE 10 2014 224 500 A1 provided first and second spring preferably omitted.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

• 1 einen Schaltplan einer erfindungsgemäßen Ventilbaugruppe.

The invention will be explained in more detail below with reference to the accompanying drawings. It shows:

• 1 a circuit diagram of a valve assembly according to the invention.

1 shows a circuit diagram of a valve assembly according to the invention 10 , The valve assembly 10 is from a pump 12 supplied with pressurized fluid, which from a tank 13 is sucked. The valve assembly 10 is to an actuator 14 For example, a cylinder or a hydraulic motor connected to control its movement.

The valve assembly 10 includes a valve body 20 , which is designed here as a valve spool of a 4/3-way valve. It is understood that any valve body are used, which may be components of a pusher or a poppet valve. By movement of the valve body 20 a free flow cross section is adjustable in at least one fluid flow path. In the present case, both the flow cross section in the inlet of the pump 13 to the actuator 14 as well as in the return from the actuator 14 to the tank 13 adjustable with a single valve body.

The valve body 20 is by means of an electric motor 23 that has a mechanical transmission 22 with the valve body 20 is motion coupled, moves. The mechanical transmission 22 is in the present case designed as a spindle drive, wherein preferably a ball screw is used. From the DE 10 2014 224 500 A1 , the CH 660 512 A5 , the DE 199 48 379 B4 and the DE 20 2007 017 894 U1 Further valve bodies are known, which are moved by means of an electric motor and a mechanical transmission. These are also usable in the context of the present invention.

The position of the valve body 20 is by means of a position sensor 21 measured. This can, for example, from the magnetic field sensor of DE 10 2014 224 500 A1 be formed. The measured value of the position sensor 21 forms the actual value 34 the control device 30 , The control device 30 forms a manipulated variable from a comparison between the actual value and a setpoint 33 , Typically, the difference between the actual value and the desired value is formed for this purpose, which is referred to as a control difference. The control difference can for example be supplied to a P or a PI controller or another continuous linear regulator. It is understood that such regulators are preferably calculated digitally and time-discretely in order to realize them cost-effectively.

The manipulated variable is typically the current and / or the voltage which is supplied to the electric motor. It is understood that multi-stage control can be used, the other control variables use, for example, the speed of the electric motor and its rotational position. As a result, a particularly fast or dynamic control can be achieved.

In normal operation, the manipulated variable is typically specified by the operator of the valve assembly, for example with a joystick. In the context of the present invention, however, this user specification is overridden when the electrical power supply 32 the control device 30 , For example, the connection to the public grid, is interrupted. In this case, the reference value used is a predetermined value, which is a safe position of the valve body 20 the valve assembly 10 equivalent. Typically, this is a blocking position in which all fluid flow paths 11 are locked, according to the middle position of the valve body 20 in 1 ,

The energy for the control process described last becomes an electrical energy store 31 taken, which to the control device 30 connected. In the electrical energy storage 31 it may be a battery and / or a capacitor and / or a fuel cell. When the control process is completed, that is, when the setpoint is substantially equal to the actual value, the control device 30 ordered shut down, so that it takes the electric energy storage substantially no further energy.

It should be noted that the valve body 20 just not provided with a return spring. Rather, it is solely due to the power of the electric motor 23 set in motion. This is preferably just designed so large that the valve body 20 attacking hydraulic flow forces and other friction forces can be safely overcome.

LIST OF REFERENCE NUMBERS

10

valve assembly

11

Fluid flow path

12

pump

13

tank

14

actuator

20

valve body

21

position sensor

22

mechanical transmission

23

electric motor

30

control device

31

electrical energy storage

32

power supply

33

manipulated variable

34

actual value

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102014224500 A1 [0002, 0010, 0015, 0016]
• CH 660512 A5 [0015]
• DE 19948379 B4 [0015]
• DE 202007017894 U1 [0015]

Claims (5)

Valve assembly (10) having a movable valve body (20) which is formed so that a free flow cross section of at least one associated fluid flow path (11) by movement of the valve body (20) is adjustable, wherein an electric motor (23) is provided, via a mechanical transmission (22) is coupled to the valve body (20), wherein a position sensor (21) is provided, with which the position of the valve body (20) is measurable, characterized in that a control device (30) is provided whose manipulated variable ( 33) is a current and / or a voltage of the electric motor (23), wherein the actual value (34) is a measured value of the position sensor (21), wherein the control device (30) to an electrical power supply (32) can be connected, wherein it an electrical energy store (31) is connected, wherein the control device (30) is set up so that its setpoint value when the power supply (32) is interrupted is set to a predetermined value, wherein the position control using electrical energy from the electrical energy storage (31) is performed. Valve assembly after Claim 1 , characterized in that the mechanical transmission (22) is designed to be self-locking, that the valve body (20) by the electric motor (23) is movable, but not vice versa. Valve assembly according to one of the preceding claims, characterized in that the mechanical transmission is formed without play. Valve assembly according to one of the preceding claims, wherein the valve body (20) is movable to the position corresponding to the predetermined value exclusively by using the electric motor (23). Valve assembly according to one of the preceding claims, wherein the valve assembly is formed in the manner of a valve disc having a first and a second planar sealing surface, wherein the first and the second sealing surface are arranged parallel to each other, facing away from each other, wherein the entire valve assembly, in particular the electric motor is arranged between the two planes defined by the first and second sealing surfaces.

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