Drive for a valve and application device

Abstract

In one aspect of the invention, an actuator for controlling a valve is provided. The valve is configured to start and / or stop the application of a fluid, in particular a liquid. The fluid application can be carried out by means of an application device. The actuator comprises a DC stepper motor, which includes an integrated threaded spindle and a spindle nut. The actuator includes a piston connected to the valve. The actuator includes a lever device configured to connect the spindle nut to the piston by lever action.

Description

[0001] The present invention relates to an actuator for a valve, i.e., an actuator device. The valve can be part of an application device. The present invention also relates to an application device comprising the actuator and the valve. Technical background

[0002] Application systems are used in numerous industrial applications, for example in the automotive, construction, energy, and semiconductor industries, as well as in industrial assembly. Application systems serve to apply media, especially viscous and / or liquid media, to or into components. Examples of liquid media include adhesives, foams (especially polyurethane foams), battery foams, and insulating foams, as well as paints and cleaning fluids. In the automotive sector, application systems are used, for example, to apply battery foams and / or adhesives to the batteries of electric vehicles, and / or to apply adhesives to body parts and / or vehicle windows, such as windshields.

[0003] An application system typically comprises a metering device, also known as a dispenser, and an application device, also known as an applicator. The metering device is used for metering, for example by controlling the flow of fluid or material, and receives the medium from a source, such as a storage container, particularly a drum. The application device is used to apply the medium to or into a component.

[0004] Application devices typically include a valve to control the fluid application. A variety of options are available for actuating the valve to open and close it. Often, the valve is actuated or controlled by compressed air. The valve's opening and closing times, as well as its holding force, are crucial for fluid application and significantly influence the appearance of the weld start and end.

[0005] Conventional valve actuators are based on pneumatic systems capable of generating sufficiently high forces and correspondingly high stroke speeds. However, there is a desire to use pneumatic valve actuators in the future to reduce dependence on a (central) compressed air supply.

[0006] Conventional electric valve actuators require a spindle or threaded spindle to convert rotary into translational motion.

[0007] To replace such pneumatic systems with conventional electric rotary drives, relatively large electric drives are required. For example, a stepper motor, such as a can-stack stepper motor, can generate its torque even when stationary and simultaneously achieve a sufficient travel speed for application valves via an integrated spindle. However, the potential torque of a can-stack motor is limited, and therefore so is its potential spindle force. In other words, a conventional can-stack motor cannot provide the necessary holding force for valves used to open and / or close application devices. Summary of the invention

[0008] It is an object of the present invention to provide an actuator for a valve that enables the holding force required for application operation. It is a further object of the present invention to provide an actuator for a valve whose design is compact and / or simple. It is a further object of the present invention to provide an actuator for a valve that does not require a compressed air supply.

[0009] At least one of the problems, or further problems, that arise for a person skilled in the art from the present disclosure are solved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims and the description.

[0010] In one aspect of the invention, an actuator for controlling a valve is provided. The valve is configured to start and / or stop the application of a fluid, in particular a liquid. The fluid application can be carried out by means of an application device. The actuator comprises a stepper motor, e.g., a DC stepper motor, which includes an integrated threaded spindle and a spindle nut. The actuator includes a piston connected to the valve. The actuator includes a lever device configured to connect the spindle nut to the piston by lever action.

[0011] In other words, the spindle nut drives a first lever arm of the lever device, with a second lever arm of the lever device being configured to raise or lower the piston. Due to the lever ratio resulting from the ratio of the lengths of the first and second lever arms, a small stroke of the spindle nut can be converted into a large stroke of the piston, and correspondingly of the valve needle. Through the lever device, the drive according to the invention can provide a higher holding force to a valve than conventional electric rotary drives of the same size. Put another way, the lever mechanism reduces the required force, allowing a small motor to perform the valve movement quickly enough.

[0012] The lever device can comprise a lever and a lever support, wherein the first lever arm can be defined as the section of the lever located between the lever support and the spindle nut. Similarly, the second lever arm can be defined as the section of the lever located between the lever support and the piston. In one embodiment, the position of the lever support can be adjustable. This allows the lever ratio to be adapted to the intended operating range of the valve actuator.

[0013] The motor, for example a DC stepper motor, can have a stator and a magnetic rotor. By generating a rotating electromagnetic field in the stator, which interacts with the rotor's gearing, the rotor can be set in motion in small, precise steps. The rotor can contain a permanent magnet. The magnetic field can be generated by applying a direct current to several coils arranged in the stator. The DC stepper motor can, in particular, be a CAN-stack stepper motor.

[0014] The lead screw can be integrated into the motor, i.e., connected to the rotor of the stepper motor. The lead screw has an external thread with a predefined pitch. The lead screw nut has an internal thread corresponding to the external thread of the lead screw. The lead screw nut can be screwed to the lead screw.

[0015] The spindle nut and the lever device can be movably connected. For this purpose, the spindle nut can have a connection, in particular a bearing, to which a first lever arm of the lever device can be connected.

[0016] The piston and the lever mechanism can be movably connected. For this purpose, the piston can have a connection, in particular a bearing, to which a second lever arm of the lever mechanism can be connected.

[0017] The fluid can be a viscous liquid.

[0018] According to this aspect of the invention, the drive operates without compressed air, so that an application system that uses this drive to control the outlet valve no longer requires a compressed air connection.

[0019] In one embodiment, the drive can further comprise a housing in which the sliding current stepper motor, the piston, and the lever device are arranged. The drive can include a return element that may be arranged coaxially to the piston between an inner wall of the housing and the piston. Preferably, the return element can be a spring.

[0020] The return element can exert a restoring force on the piston. The return element incorporates a safety function that prevents the valve from remaining open if the actuator briefly fails. This function can also be described as a "fail-safe" feature. Furthermore, during actuator operation, the return element can ensure faster valve closure, allowing for more precise fluid application.

[0021] In another aspect, an application device is provided. The application device comprises an actuator and a valve, as described above. The actuator moves the piston into a first position in which the valve is open and the fluid can be applied. The actuator moves the piston into a second position in which the valve is closed and the fluid flow is stopped.

[0022] The valve can comprise a valve pin and a valve seat. The piston can be connected to the valve pin or formed integrally with it. In the second position of the piston, the valve pin is designed to engage positively with the valve seat, thereby stopping the fluid flow. Brief description of the characters

[0023] Embodiments of the present disclosure are described in detail below with reference to a figure. Fig. Figure 1 shows an embodiment of a drive 1 for controlling a valve 25, 26 according to one aspect of the invention. Detailed description

[0024] Fig. Figure 1 shows an actuator 1 for controlling a valve 25, 26. The actuator 1 can have a housing 30 in which a DC stepper motor 10, a piston 21 and a lever device 15 are arranged.

[0025] The DC stepper motor 10 comprises a threaded spindle 11, which can be integrated into the stepper motor 10. A spindle nut 12 can be arranged on the threaded spindle in a screw connection. By applying a direct current (DC), the threaded spindle can be set into rotary motion, which causes a stroke of the spindle nut 12. The stroke of the spindle nut 12 is Fig. 1 represented by the double arrow.

[0026] The piston 21 can be connected to a valve needle 25, which can engage positively in a valve seat 26 to close the valve. The valve seat 26, also referred to as a sealing seat, can be associated with the application device (not shown), i.e., form a fluid connection of the application device.

[0027] The piston 21 is connected to the spindle nut 12 by a lever device 15. The lever device can have a lever support (through the triangle in Fig. (1 sketched) comprise the lever of the lever device 12, which divides it into a first lever arm and a second lever arm. The lever can be rotatably mounted on the lever support to mechanically connect the spindle nut 12 and the piston 21. The ratio of the two lever arms defines the lever ratio, by which a small stroke of the spindle nut 12 can be translated into a large stroke of the piston 21.

[0028] In one embodiment, a return element 22 can be arranged in a partial space above the piston 21, connecting the piston 21 to an inner surface of the housing 30. The return element 22 is in Fig. 1 depicted as a feather.

[0029] The lever device allows the linear movement of the spindle nut 12 to be transferred to the valve needle 12 with an additional force applied to lift the valve needle out of or push it into the valve seat 26. This allows fluid flow through the valve 25, 26 to be controlled with the holding force required for application operation.

Claims

[1] Actuator (1) for a valve (25, 26), wherein the valve (25, 26) is configured to start and / or stop an application of a fluid, in particular a liquid, wherein the actuator (1) comprises: - a motor (10) with a threaded spindle (11) and a spindle nut (12), - a piston (21) connected to the valve (25, 26), and - a lever device (15) which is designed to connect the spindle nut (12) to the piston (21) by lever action. [2] Drive according to claim 1, wherein the drive (1) further comprises: - a housing (30) in which the motor (10), the piston (21) and the lever device (15) are arranged, and - a return element (22) which is arranged coaxially to the piston (21) between an inner wall of the housing (30) and the piston (21), wherein the return element (22) is preferably a spring. [3] Drive according to claim 1 or 2, wherein the motor (10) is designed as a stepper motor. [4] Application device comprising a drive (1) according to one of the preceding claims, and the valve (25, 26), wherein the drive (1) can move the piston (21) into a first position in which the valve (25, 26) is open and the fluid can be applied, and the piston (21) can be moved into a second position in which the valve (25, 26) is closed and fluid flow is stopped.

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