Patent Publication Number: US-2022220626-A1

Title: Coating apparatus for coating components

Description:
FIELD 
     The present invention relates to a coating device for coating components, in particular for nickel-plating spark plug housings. In addition, the present invention relates to a coating installation. 
     BACKGROUND INFORMATION 
     The use of drum coating for the coating of components, such as spark plug housings, is conventional. Here, the components are placed into a drum as bulk goods, and the components in the drum subsequently run through all the coating steps as bulk goods. 
     SUMMARY 
     A coating device according to the present invention may offer the advantage of an improved device by which very high-quality coatings of components can be produced in a short time. According to an example embodiment of the present invention, this may be achieved by a coating device that includes a housing having an outer anode, an inner anode, and a voltage-generating device. The outer anode is thus part of the housing, and is designed to receive the component, which is preferably a spark plug housing; i.e. to grasp the component. The inner anode is capable of being introduced into a through-opening of the component. In addition, the voltage-generating device is designed to generate a first voltage between the outer anode and the component, as well as a second voltage between the inner anode and the component. Moreover, the housing has an inlet and an outlet. Through the inlet, a process medium can be introduced into the housing, and the process medium can be discharged from the housing via the outlet. 
     Thus, the coating device is realized in such a way that it can accept in each case exactly one component, and both an outer side and an inner side of the component can be coated, preferably nickel-plated, completely and with high quality. Due to the direct flow of the process medium around the component, a very high coating speed can be achieved, i.e., a very fast deposition of a layer on the component. 
     Preferred developments of the present invention are disclosed herein. 
     Preferably, the housing additionally includes a cover having a clamping device. The clamping device is designed to clamp the component so as to hold the component in a predefined position inside the outer anode. That is, the component is held in a defined fashion in the housing solely by the clamping device. 
     Particularly preferably, the component is a spark plug housing having a ground electrode. The clamping device is designed to clamp the ground electrode. There thus results a particularly simple possibility for mounting the spark plug housing inside the outer anode. 
     Preferably, the clamping device is designed so that it at least partly covers a surface of the ground electrode in the clamped state. In particular, in this clamped state the clamping device covers at least 80%, particularly preferably at least 95%, of the surface of the ground electrode. That is, the clamping device grasps the ground electrode of the spark plug housing in such a way that on the one hand, a defined mounting of the spark plug housing inside the outer anode is thereby enabled, and on the other hand a surface of the ground electrode is largely covered. In this way, the ground electrode is prevented from being able to come into contact with the process medium during the coating process, and is thus excluded from the coating. This is particularly advantageous if only a partial coating of the spark plug housing is intended. 
     In addition, it is advantageous if the process medium is a nickel electrolyte. In this way, the coating corresponds to a nickel-plating of the component, i.e. a nickel coating is produced on the component. 
     Preferably, the inner anode can be adjusted along a longitudinal axis of the housing in order to adapt a production of the coating to the inner side of the component. For example, in this way a different layer thickness of the coating on the inner side of the component can be achieved. 
     Preferably, the coating device additionally has a flow-regulating device in order to regulate a flow of the process medium through the housing. The flow-regulating device is a perforated diaphragm that is preferably rotatable. For example, such a rotatable perforated diaphragm can be provided as two discs that can be rotated relative to one another, having a plurality of through-holes. By rotating the two discs relative to one another, the overlapping of the through-holes changes, so that an overall open flow cross-section, and thus a flow through the housing, can be set. 
     Particularly preferably, using the flow-regulating device a first flow between the inner anode, and/or a second flow between the outer anode, and the component can respectively be regulated. Here it is particularly advantageous if the first flow and the second flow can be regulated independently of one another using the flow-regulating device in order to enable the flow of the process medium through the housing to be adapted particularly flexibly to the desired properties of the coating on both the inside and the outside of the component. 
     In addition, the present invention provides a coating installation that includes at least one, but preferably at least  20 , and particularly preferably  48 , coating devices. In addition, the coating installation includes, per coating device, at least one, preferably exactly two voltage-generating devices per coating device. In this way, a particularly efficient and rapid coating of the components in an overall installation can be achieved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described on the basis of an exemplary embodiment in connection with the Figure. In the Figure, functionally identical components are provided with the same reference characters. 
         FIG. 1  shows a simplified schematic sectional view of a coating device according to a preferred exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
       FIG. 1  shows a simplified schematic sectional view of a coating device  1  according to a preferred exemplary embodiment of the present invention. Shown here is an operating state of coating device  1  while a component  2  situated in coating device  1  is coated. Component  2  is a spark plug housing having a straight ground electrode  22 . 
     Coating device  1  includes a housing  3  having an outer anode  4 . Housing  3  extends substantially along a longitudinal axis  10 . Component  2  is situated inside outer anode  4 . Outer anode  4  has an inner contour that is matched to an outer contour of component  2 . 
     An inner anode  5  of coating device  1  is situated inside a through-opening  21  of component  2 . Inner anode  5  is fastened to a floor  35  of housing  3  by a screw  51 . Using screw  51 , an adjustment of inner anode  5  along longitudinal axis  10  can be carried out. 
     In addition, housing  3  includes a cover  8  having a clamping device  81 . Ground electrode  22  of component  2  is clamped in clamping device  81  in order in this way to hold component  2  in a defined position inside outer anode  4 . In  FIG. 1 , ground electrode  22  is shown in a state in which it is not yet bent, and thus also extends in the direction of longitudinal axis  10 . As can also be seen in  FIG. 1 , due to the clamping of ground electrode  22  in clamping device  81 , more than 90% of the surface of ground electrode  22  is covered by clamping device  81 , in order to prevent coating of ground electrode  22  on precisely this covered surface. 
     In addition, housing  3  has on floor  35  an inlet  31  via which a process medium can be introduced into housing  3  in direction  71 . Moreover, in housing  3  an outlet  32  is provided via which the process medium can be discharged from housing  3  in direction  72 , after it has flowed over or through component  2 . 
     In addition, coating device  1  includes a flow-regulating device  9  that is situated at the transition between floor  35  and outer anode  4 . Flow-regulating device  9  is designed as a perforated diaphragm having a plurality of holes  91  in order to regulate, by rotation, a flow, in particular a volume flow, of the process medium through housing  3 . 
     The process medium is a nickel electrolyte by which a nickel coating can consequently be produced on component  2 . 
     In order to produce such a nickel coating on component  2 , coating device  1  has in addition a voltage-generating device  6 . Using voltage-generating device  6 , a first voltage can be generated between outer anode  4  and component  2 . In addition, a second voltage can also be generated between inner anode  5  and component  2 . In this way, by applying the first voltage and the second voltage while the process medium flows through housing  3 , the nickel coating can be produced both on the inner side and on the outer side of component  2 .