Actuator device

Abstract

The invention relates to an actuator device (1) with a dimensionally stable housing (4) in which an interior space (14) is formed, wherein the interior space (14) is formed by a base surface (15), a top surface (16) opposite the base surface (15) which is spaced away from the base surface (15) in a direction perpendicular to the base surface (15), and a side surface (17) connecting the base surface (15) with the top surface (16), and with a rubber-elastic membrane (18) arranged in the interior space (14) which is integrally connected with the housing (4), wherein the housing (4) and the membrane (18) are jointly manufactured by means of an additive manufacturing process, in particular a 3D printing process.

Description

The invention relates to an actuator device having a housing which is fixed in terms of shape and in which an interior space is formed, the interior space being formed by a base surface, a cover surface which lies opposite the base surface and is spaced apart from the base surface in a direction perpendicular to the base surface, and a side surface which connects the base surface to the cover surface, and having a rubber-elastic membrane which is arranged in the interior space.Actuator devices, in particular actuator devices designed as diaphragm valves, are known from the prior art, in which the diaphragm arranged in the interior of the housing is used as a switching element which can assume at least two positions, for which purpose the diaphragm must be designed to be rubber-elastic. The housing, on the other hand, should be designed to be rigid in shape, so that when the actuator device is used as intended, no deformation of the housing relevant to the function of the actuator device occurs. The intended use provides, in particular, pressurization of the interior with compressed air in order to cause a targeted deformation of the membrane. The individual components of actuator devices of this type, in particular the housing and the membrane, are produced separately, i.e. the housing is produced independently of the membrane and the two components are assembled to form an actuator device in a downstream production step or in a plurality of downstream production steps, which increases the production time and the production costs.DE 10 2011 015 646 A1 discloses a fluid-actuated diaphragm drive which has two hood-shaped housing parts which are placed coaxially against one another with openings facing one another. The two housing parts are fixed to one another on their side walls adjoining one another by a bayonet connection device. The two housing parts are designed such that the locking projections of the bayonet connection device are hidden from view from the outside.DE 41 20 913 A1 discloses a piston-cylinder unit. In the piston-cylinder unit, a piston is movable relative to a cylinder, its movement is detectable by a displacement sensor, and a rolling diaphragm rolling between the piston wall and the cylinder wall is provided as a seal, wherein at least a part of the cylinder wall on the one hand and the piston wall on the other hand are designed as plates of an electric cylinder capacitor, between which the rolling diaphragm covers the respectively overlapping electrically conductive wall parts of the piston and cylinder as a dielectric, and wherein the capacitance of the capacitor changing during the stroke movement is detectable by an evaluation unit as a displacement measurement for the stroke distance of the piston.The object of the present invention is to provide an actuator device which can be produced in one production step.This object is achieved according to the invention in that the rubber-elastic membrane is connected integrally to the housing, wherein the housing and the membrane are produced jointly by means of an additive manufacturing method, in particular a 3D printing method.In this way, there is the advantageous possibility that the actuator device can be produced in one production step without having to provide an assembly step. In addition, by using an additive manufacturing method, in particular a 3D printing method, it is possible to choose the geometry of the components, for example of the shape-fixed housing and the rubber-elastic membrane, almost freely. Thus, for example, a membrane receiving space in the housing, which receives the membrane in sections, can have one or more undercuts, which cannot be produced or can only be produced with great effort by means of customary production methods, for example by means of an injection molding method or a machining method. All suitable additive production methods can be used here, in particular methods such as fused deposition modeling, laser sintering, laser or electron beam melting. Within the meaning of the present application, rubber-elastic is understood to mean that the membrane can be elastically deformed under the action of a force during operation of the actuator device in order to change from a first position to a second position, for example, and vice versa. The force effect is in particular caused by a pressurization of the interior with compressed air; a pressure interval for the compressed air provided for this purpose is in a range of a few millibars up to 6 bar. The rubber-elastic properties are achieved by a corresponding selection of material and by a corresponding geometry of the membrane. By shape-proof, however, is meant in the present case that during operation of the actuator device no deformation or no significant deformation, i.e. a deformation influencing the operation of the actuator device, occurs. For this purpose, a corresponding material for producing the housing and / or a corresponding housing geometry can be provided.A first position is understood in the present case to mean a position in which the membrane is in its initial position, i.e. in the position in which it was produced, in particular printed. Accordingly, this position can also be referred to as an unactuated state or as a production state. The second position, on the other hand, is a position that the membrane assumes or has assumed during and possibly after the action of force. This position can also be referred to as an activated state.The dimensionally stable housing is preferably formed by a housing base side and a housing top side which are connected to one another via a housing side wall. Purely by way of example, the housing has a substantially rectangular basic shape, such that the housing side wall is formed from four sections, wherein in each case two sections are oriented parallel to one another and are oriented orthogonally to the other sections. The sections oriented orthogonally to one another can in this case each adjoin one another or be connected to one another by transition sections of the housing side wall, for example in the form of rounded corners. The housing has a longitudinal axis along which the housing base side and the housing top side are spaced apart from one another, a transverse axis running orthogonally to the longitudinal axis, with which a transverse direction of the housing coincides, and a height axis which is oriented orthogonally to the longitudinal axis and orthogonally to the transverse axis.If the actuator device according to the invention is produced by means of a 3D printing method, the printing begins with the housing base side and a print head of a printer is moved in a suitable manner along an X direction with which the later transverse axis of the housing coincides and along a Y direction with which the later height axis of the housing coincides, wherein a first material layer is applied to a tool table of the printer. After complete application of the first material layer, the print head is moved away from the tool table along a Z direction with which the later longitudinal axis of the housing coincides, and the print head is again moved in a suitable manner along the X direction and along the Y direction and a new material layer is applied to the previously applied material layer. Accordingly, the actuator device is printed along the later longitudinal axis of the housing.Production by means of an additive manufacturing method and in particular by means of a 3D printing method and production in only one process step additionally has the advantage that the actuator device can be produced at any desired location, as long as the production method used can be carried out at this location. It is thus possible, for example, for a manufacturer of the actuator device to provide a customer only with the necessary CAD files and the necessary information about the material to be used and for the customer, after obtaining these data and information, to print the actuator device directly on site. Long delivery times with high utilization of the manufacturing capacities of the manufacturer and long delivery routes and emissions arising from transport to the customer can thus be avoided.Advantageous further developments of the invention are evident from the dependent claims.In a further configuration of the actuator device, the diaphragm is produced from a first material and the housing is produced from a second material. It is thus possible, for example, for the first material to be softer than the second material, wherein in particular a plastic or a metal is suitable as the first material and a further plastic or a further metal is suitable as the second material. The first material is selected in such a way that it possesses the necessary rubber-elastic properties in order to enable deformation of the membrane under the action of force. The use of a harder material as the second material, on the other hand, enables an improvement or at least a maintenance of the shape-resistant properties required for the housing with a lower use of material.In the context of the application, plastic is understood to mean a plastic that is suitable for processing by means of the selected additive manufacturing method. Analogously, a metal is understood to mean a metal which is suitable for processing by means of the selected additive manufacturing method.The membrane is preferably arranged in the interior space in such a way that a first working space is formed between the membrane and the base surface, which working space is fluidically connected to a first fluid connection formed in the housing. Via the first fluid connection, the first working chamber can be fluidically connected to a fluid source, in particular to a compressed air source, in order to conduct fluid, for example compressed air, into the first working chamber. By means of the introduced fluid, the pressure in the first working chamber is increased, whereby a force is exerted on the diaphragm in order to transfer it from the first position into the second position or vice versa.Advantageously, a piston element is arranged in the interior that is displaceable along an axis of movement and is connected integrally to the membrane, wherein the cover surface has a through-opening through which the piston element protrudes in sections relative to the housing when the membrane is in an activated state, and wherein the piston element is produced together with the housing and the membrane by means of the additive manufacturing method, in particular a 3D printing method. Thus, the actuator device can also be referred to as a diaphragm cylinder, in which the region of the piston element that protrudes in sections relative to the housing can be used for manipulating an element that is connected to the piston element or can be contacted by it.Preferably, a second working space is formed between the piston element and the cover surface, which is fluidically connected to a second fluid connection formed in the housing. In this embodiment, the second working space can be supplied with a fluid, for example compressed air, via a fluid source that can be connected to the second fluid connection, in particular a compressed air source. An actuator device designed in this way can also be referred to as a double-acting diaphragm cylinder. By introducing fluid into the second working chamber, the pressure in the second working chamber increases, so that a force is exerted on the diaphragm which is directed counter to the force caused by the pressure in the first working chamber. If the force caused by the pressure in the second working chamber is greater than the force caused by the pressure in the first working chamber, the diaphragm is displaced from the second position back into the first position. Accordingly, the position of the diaphragm can be changed by adjusting the respective pressure in the first working chamber and in the second working chamber.Advantageously, it can be provided that that pressure chamber through which a lower force is to be exerted on the membrane for the desired position of the membrane is vented in order to reduce the pressure necessary for the displacement.An embodiment is considered to be particularly advantageous in which a sealing element is arranged in the housing, which sealing element is integrally connected to the piston element and the housing, wherein the sealing element is produced together with the piston element, the housing and the membrane by means of the additive manufacturing method. Preferably, the sealing element is arranged in a sealing element receiving space formed in the housing. In this embodiment, the second working chamber is formed between the sealing element and the diaphragm, and the sealing element seals the second working chamber from the environment.In a further embodiment, the sealing element is made of the first material and the piston element is made of the second material. When manufacturing the sealing element from the first material, the advantage is that the sealing element has the same rubber-elastic properties as the membrane in order to ensure both sealing and displaceability of the piston element. Analogously, if the second material is used for its production, the piston element has the required shape-resistant property. Advantageously, a separating layer made of a material different from the second material can be arranged between the piston element and the base surface of the interior, by means of which separating layer a cohesive connection between the piston element and the base surface can be prevented during production, in particular during printing, even if no pronounced cooling phase is provided. It is also possible to produce the separating layer from a soluble, in particular water-soluble, material, so that the separating layer can be removed by post-treatment after production of the actuator device.Advantageously, the sealing element is designed as a spring element, in particular as a bellows-like spring element. The sealing element configured as a spring element makes it possible that, when the first working chamber is correspondingly ventilated, the piston element is displaced from the second position into the first position by the spring action of the sealing element.In a further embodiment, the membrane has a first self-holding position, for example the non-activated state, and a second self-holding position, for example the activated state, which is different from the first self-holding position, wherein a first actuating force has to be applied for leaving the first self-holding position, and wherein a second actuating force has to be applied for leaving the second self-holding position. In this context, in the context of the present application, a self-holding position is understood to mean a position in which the membrane, after reaching it, remains automatically without further application of force, in particular without a holding force, and leaves this position when an applied actuating force is exceeded, wherein the transition from the first self-holding position to the second self-holding position takes place only by means of the elasticity of the membrane, without any driving force of any kind having to be applied to the membrane for this transition. Thus, for example, in this embodiment, only for a switch, i.e. a change from the activated state to the non-activated state or from the non-activated state to the activated state, a fluid supply into the first working space or into the second working space is required, whereby the consumption of fluid can be reduced.Preferably, an angle formed between the base surface and each top surface element forming the top surface is in the range of 45° to 75° or 105° to 135°. If, during the production of the ceiling surface elements forming the ceiling surface, the above-described range for the angle between the respective ceiling surface element and the base surface is observed, the ceiling surface can be produced, in particular printed, without the use of support structures, since in this angle range the currently produced material layer is also sufficiently supported in the event of a protrusion over the previously printed and sometimes already solidified or partially solidified material layer.In an alternative embodiment, an opening is formed on the cover surface, which is surrounded by a membrane seat formed on the cover surface, wherein a fluid space is formed between the membrane and the cover surface, which fluid space is fluidically connected to a second fluid connection formed in the housing, and wherein the membrane in an activated state closes the opening in a fluid-tight manner by bearing against the membrane seat. In this context, the actuator device can also be referred to as a diaphragm valve.The invention is explained in more detail below with reference to the attached drawings and shown therein FIG. 1 shows an actuator device in an isometric view, FIG. 2 shows an actuator device in a sectional representation in an isometric view, and FIG. 3 shows the sectional illustration of the actuator device from FIG. 2 in a side view.FIG. 1 shows an embodiment of an actuator device 1 with a fixed-shape housing 4 having a housing base side 2 and a housing top side 3, which are connected to one another by a housing side wall 5. The housing 4 has a substantially rectangular basic shape, so that the housing side wall 5 is formed from four sections, wherein two sections each are oriented parallel to one another and oriented orthogonally to the other sections. The sections oriented orthogonally to one another are connected to one another by way of example by transition sections embodied as rounded corners. The actuator device 1 shown is produced by means of a 3D multicomponent printing method, wherein, purely by way of example, printing is carried out starting from the housing base side 2 to the housing top side 3. For this purpose, a material layer is applied one after the other to a tool table of the printer, not shown.The housing 4 has a longitudinal axis 6, along which the housing base side 2 and the housing top side 3 are spaced apart from one another. A transverse axis 7 runs orthogonally to this longitudinal axis 6, with which a transverse direction of the housing 4 coincides. A height axis 8 of the housing 4 is oriented orthogonally to the longitudinal axis 6 and orthogonally to the transverse axis 7. The longitudinal axis 6, the transverse axis 7 and the height axis 8 form a Cartesian coordinate system.A first fluid connection 9 and a second fluid connection 10 are each formed on a section of the housing side wall 5 in the form of a bore which is surrounded by an abutment surface 11 which is of substantially planar design and runs parallel to the section of the housing side wall 5 and is spaced apart therefrom along the height axis 8. The first fluid connection 9 and the second fluid connection 10 are designed to receive connecting elements, in particular pneumatic quick connectors, which are not shown, so that the first fluid connection 9 can be connected to a first fluid supply line, which is not shown, and the second fluid connection 10 can be connected to a second fluid supply line, which is not shown. On the housing top side 3, a through-opening 12 is formed, the central axis of which coincides with the longitudinal axis 6 of the housing 4 and through which a piston element 13 arranged in the housing 4 projects in sections.As can be seen from FIGS. 2 and 3, the piston element 13 is accommodated in an interior space 14 formed in the housing 4, which is formed by a base surface 15, a top surface 16 spaced apart from the base surface 15 along the longitudinal axis 6, and a side surface 17 connecting the base surface 15 and the top surface 16. A rubber-elastic membrane 18 is integrally connected to the piston element 13 and to the housing 4, wherein the housing 4, the piston element 13 and the rubber-elastic membrane 18 are produced by means of an additive manufacturing method, in particular a 3D printing method. The diaphragm 18 is made of a first material, while the housing 4 and the piston element 13 are made of a second material. The diaphragm 18 is accommodated in a first diaphragm accommodation chamber 20 formed in a diaphragm section 19 of the piston element 13 in sections and in sections in a second diaphragm accommodation chamber 21 formed in the side surface 17. The first membrane receiving space 20 extends from an outer side 22 of the membrane section 19 toward the longitudinal axis 6. the second membrane receiving space 21 extends substantially parallel and along the longitudinal axis 6. Due to the rubber-elastic configuration of the diaphragm 18, the piston element 13 can be displaced in the housing 4 along an axis of movement which coincides, for example, with that of the longitudinal axis 6.A rubber-elastic sealing element 23 is integrally connected to the piston element 13 and to the housing 4, wherein the sealing element 23 is likewise produced by means of an additive manufacturing method, in particular a 3D printing method, preferably from the first material. The sealing element 23 is accommodated in a first sealing element accommodation chamber 25 formed in a sealing element section 24 of the piston element 13 in sections and in sections in a second sealing element accommodation chamber 26 formed in the cover surface 16 of the interior 14. A first section 27 of the first sealing element receiving space 25 extends from an outer side 28 of the sealing element section 24 of the piston element 13 toward the longitudinal axis 6, and a second section 29 of the first sealing element receiving space 25 adjoining the first section 27 extends substantially along the longitudinal axis 6, so that the first sealing element receiving space is formed substantially T-shaped. The second sealing element receiving space 26 extends substantially perpendicular to the longitudinal axis 6 of the housing 4.The membrane 18 is arranged in the interior 14 in such a way that a first working space 30 is formed between the membrane 18 and the base surface 15 of the interior 14, which working space is fluidically connected to the first fluid connection 9 via a first fluid channel, which is not shown and is formed in the housing 4. The sealing element 23 is arranged in the interior 14 in such a way that a second working space 31 is formed between the sealing element 23 and the membrane 18, which working space is fluidically connected to the second fluid connection 10 via a second fluid channel, which is not shown and is formed in the housing 4.When fluid is supplied into the first working chamber 30, the piston element 13 is displaced from the first position shown in the figures, which corresponds to the production state and can also be referred to as the non-activated state, into a second position, which can also be referred to as the activated state, and is displaced again from the second position into the first position when fluid is supplied into the second working chamber 31 and the first working chamber 30 is correspondingly vented.In an alternative embodiment of the actuator device 1, which is not shown, the sealing element 23 can be designed as a spring element, in particular as a bellows-like spring element, so that, when the first working chamber 30 is correspondingly ventilated, the piston element 13 is displaced from the second position into the first position by the spring action of the sealing element 23 designed as a spring element.Furthermore, the cover surface 16 of the interior space 14 is formed from a plurality of cover surface elements 32, 33, 34, 35, 36, 37, wherein an angle of 45° or 135° is situated between the base surface 15 of the interior space 14 and each of the cover surface elements 32, 33, 34, 35, 36, 37, wherein the second sealing element receiving space 26 is arranged between the cover surface elements 32 and 34 and also 33 and 35, and wherein the sealing element 23 bears against the cover surface elements 34, 35, which can correspondingly also be referred to as sealing element bearing surfaces. The cover surface elements 36, 37 serve as a stop against which a stop surface 38 formed on the piston element 13 abuts in the second position, i.e. in the activated state, so that these cover surface elements 36, 37 limit the displacement of the piston element 13 along the longitudinal axis 6 in order to prevent an unacceptably high deformation of the membrane 18 or of the sealing element 23.In the production state of the actuator device 1 shown, the first membrane receiving space 20 and the second membrane receiving space 21 are spaced apart from one another along the longitudinal axis 6 in such a way that the membrane region 39 not accommodated in the first membrane receiving space 20 or second membrane receiving space 21 forms an angle of 45° with the base surface 15 of the interior space 14. In the production state of the actuator device 1 shown, the first sealing element receiving space 25 and the second sealing element receiving space 26 are spaced apart from one another along the longitudinal axis 6 in such a way that the sealing element region 40 not received in the first sealing element receiving space 25 or second sealing element receiving space 26 forms an angle of 45° with the base surface 15 of the interior space 14. This type of configuration enables the joint, integrated production of the housing 4, piston element 13, the membrane 18 and the sealing element 23. For a rapid production without a pronounced cooling phase, a separating layer 41 is arranged between the piston element 13 and the base surface 18 of the interior space 14, said separating layer consisting of a material different from the second material. This prevents the housing 4 and the piston element 13 from being connected to one another in a materially integral manner during production. It can also be provided that the separating layer 41 performs a further sealing function or that the separating layer 41 consists of a soluble material, in particular water-soluble material, which is removed from the housing 4 after production, for example by post-treatment of the actuator device 1 in a water bath.In an embodiment of the actuator device 1 that is not shown, the actuator device 1 is designed as a diaphragm valve. For this purpose, an opening is formed on the cover surface 16, which is surrounded by a membrane seat formed on the cover surface 16, wherein a fluid space is formed between the membrane 18 and the cover surface 16, which fluid space is fluidically connected to a second fluid connection formed in the housing 4, and wherein the membrane 18 in an activated state closes the opening in a fluid-tight manner by bearing against the membrane seat. For example, a fluid flow from the second fluid connection to the opening can be released by means of the membrane 18 when the membrane 18 is in a non-activated state and can be closed accordingly when the membrane 18 is in an activated state. In this embodiment, the membrane 18 is in the activated state when a greater pressure is present in a first working space, which is also formed between the base surface 15 of the interior space 14 and the membrane 18 in this embodiment, than in the fluid space. Accordingly, a switching, i.e. a change from the activated state to the non-activated state or from the non-activated state to the activated state, can be realized by adjusting the pressure in the fluid chamber and / or in the first working chamber. Alternatively, the membrane 18 can also be arranged in the housing 4 in such a way that the membrane 18 closes the membrane seat in a fluid-tight manner in a non-activated state and releases it in the activated state.

Claims

Actuator device (1) having a housing (4) which is fixed in shape and in which an interior space (14) is formed, wherein the interior space (14) is formed by a base surface (15), a cover surface (16) which lies opposite the base surface (15) and is spaced apart from the base surface (15) in a direction perpendicular to the base surface (15), and a side surface (17) which connects the base surface (15) to the cover surface (16), and having a rubber-elastic membrane (18) which is arranged in the interior space (14) and is connected integrally to the housing (4), wherein the housing (4) and the membrane (18) are produced jointly by means of an additive manufacturing method, in particular a 3D printing method.Actuator device according to Claim 1, characterized in that the diaphragm (18) is produced from a first material and the housing (4) is produced from a second material.Actuator device according to Claim 1 or 2, characterized in that the membrane (18) is arranged in the interior space (14) in such a way that a first working space is formed between the membrane (18) and the base surface (15), said first working space being fluidically connected to a first fluid connection (9) formed in the housing (4).Actuator device according to one of the preceding claims, characterized in that a piston element (13) which is displaceable along an axis of movement and is connected integrally to the membrane (18) is arranged in the interior space (14), wherein the cover surface (16) has a through-opening through which the piston element (13) projects in sections with respect to the housing (4) when the membrane (18) is in an activated state, and wherein the piston element (13) is produced jointly with the housing (4) and the membrane (18) by means of the additive manufacturing method.Actuator device according to Claim 4, characterized in that a second working space (31) is formed between the piston element (13) and the cover surface (16), said second working space being fluidically connected to a second fluid connection (10) formed in the housing (4).Actuator device according to Claim 4 or 5, characterized in that a sealing element (23) is arranged in the housing, said sealing element being connected integrally to the piston element (13) and the housing (4), wherein the sealing element (23) is produced jointly with the piston element (13), the housing (4) and the membrane (18) by means of the additive manufacturing method.Actuator device according to Claim 6, characterized in that the sealing element (23) is produced from the first material and in that the piston element (13) is produced from the second material.Actuator device according to Claim 6 or 7, characterized in that the sealing element (23) is designed as a spring element.Actuator device according to one of Claims 1 to 7, characterized in that the diaphragm (18) has a first self-holding position and a second self-holding position which differs from the first self-holding position, wherein a first actuating force has to be applied for leaving the first self-holding position, and wherein a second actuating force has to be applied for leaving the second self-holding position.Actuator device according to one of the preceding claims, characterized in that an angle formed between the base surface (15) and each cover surface element (32, 33, 34, 35, 36, 37) forming the cover surface (16) is in the range from 45° to 75° or from 105° to 135°.Actuator device according to Claim 3, characterized in that an opening is formed on the cover surface (16), said opening being surrounded by a membrane seat formed on the cover surface (16), wherein a fluid space is formed between the membrane (18) and the cover surface (16), said fluid space being fluidically connected to a second fluid connection formed in the housing (4), and wherein the membrane (18), in an activated state, seals the opening in a fluid-tight manner by bearing against the membrane seat.

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