Patent Publication Number: US-2023146765-A1

Title: Method of painting a vehicle brake component using a sealing plug

Description:
FIELD 
     The present disclosure relates to a method for painting a component of a vehicle brake, in particular for painting a component of a utility vehicle brake, wherein the component has a recess which extends in the direction of a longitudinal axis and which has an inner face which is intended to be kept free from paint. The present disclosure particularly relates to such cataphoretic dip coating methods but can also be used for other methods. The present disclosure particularly relates to the painting of brake calipers of utility vehicle brakes but can in principle also be used for all components which have recesses with inner faces which are intended to be kept free from paint. 
     BACKGROUND 
     Vehicle brakes, in particular utility vehicle brakes, are subjected to environmental influences during operation over their service-life and are thereby subjected to corrosion. In order to ensure adequate operational reliability, vehicle brakes, in particular utility vehicle brakes, generally have to demonstrate their corrosion resistance by way of test measures, such as, for example, salt water spray tests. 
     In order to improve the corrosion resistance of the components for vehicle brakes, vehicle brakes are coated with corrosion-inhibiting paints. A conventional method is, for example, so-called cathodic or cataphoretic dip coating (CDC) which is an electrochemical method in which paint particles are deposited on the component in an immersion bath under the influence of an electrical field. 
     The recesses which are intended to be kept fee from paint should, for example, contain no paint since they have to comply with tight dimensional tolerances, for instance, as guiding holes which would be impaired by painting. In the prior art, it has therefore been necessary either to again free the recesses from paint after a completed painting operation or to close the recesses from the outer side. This closing of the recesses from the outer side was carried out by operating devices, such as sealing disks, being fitted at the end side and being axially tensioned against the end face. A disadvantage of these attempts has been that the operational complexity was high and the sealing disks, which have been fitted from the outer side, have also always covered a portion of the end faces of the components so that after the painting method has been carried out, and the operating devices for closing the recess at the end face have been removed, unpainted locations that then do not have the required corrosion resistance were present. 
     SUMMARY 
     An object of the present disclosure is consequently to improve the corrosion resistance of components of a vehicle brake by providing an improved method for painting the components. 
     The present disclosure achieves the object by a method for painting a component of a utility vehicle brake, wherein the component has a recess which extends in the direction of a longitudinal axis and which has an inner face which is intended to be kept free from paint, the method including the steps of: preparing the component, introducing a sealing plug into the recess of the component, wherein the sealing plug has a sealing face and the sealing face inside the recess, with respect to the longitudinal axis, is moved into sealing abutment with the inner face in a radial direction, and painting the component after the sealing plug has been introduced. 
     The present disclosure follows the approach that the sealing plug performs its sealing function exclusively inside the recess in that it moves in a radial direction into sealing abutment with the inner face of the recess when it is introduced. According to the present disclosure there is in particular no sealing in an axial direction with respect to the end outer faces of the recess. As a result of this development of the sealing plug, and the concentration on a sealing in a radial direction against the inner face of the recess, so-called blind spots are prevented from remaining free during the painting on the outer face of the vehicle brake. Corrosion at such locations cannot subsequently occur, whereby the corrosion resistance of the components of the vehicle brake is significantly improved. 
     The method is accordingly advantageously developed in that the component has an end face in which the recess is introduced and the sealing plug is introduced into the recess in such a manner that, in the introduced state, the sealing plug is spaced apart with respect to the end face. 
     In another preferred embodiment, the end face described above is a first end face and the component further has a second end face, wherein the recess extends from the first end face to the second end face through the component, wherein the component is preferably a brake caliper, and the sealing plug is introduced into the recess in such a manner that, in the introduced state, the sealing plug is spaced apart with respect to the first end face and the second end face. 
     In another preferred embodiment, there is arranged inside the recess a sliding sleeve that has a sliding face that in turn forms a portion of the inner face of the recess. Generally, such sliding sleeves are pressed into the recesses. The method is in this regard advantageous with respect to the prior art since the pressing-in of the sliding sleeves can also already be carried out before the painting. The sealing plug reliably prevents paint from penetrating into the recess and being deposited in an undesirable manner on the sliding sleeve. 
     In a preferred development, the sealing plug is introduced in such a manner that, in the introduced state, it is preferably extensively in sealing abutment with at least one sealing face against the sliding face of the sliding sleeve. 
     If the sealing plug has a plurality of sealing faces, these are also referred to together as a sealing face arrangement. 
     In another preferred embodiment, the sealing face is a first sealing face and the sealing plug further has at least a second sealing face which is arranged in the longitudinal direction with spacing from the first sealing face on the sealing plug, wherein the sealing plug is introduced in such a manner that it is also brought with the second sealing face into sealing abutment with the inner face within the recess with respect to the longitudinal axis in a radial direction. 
     In a further preferred manner, the sliding sleeve is a first sliding sleeve and inside the recess there is further arranged a second sliding sleeve which has a second sliding face which forms a part of the inner face of the recess. Preferably, the sealing plug is then introduced in such a manner that, in the introduced state, it is preferably extensively in sealing abutment with the second sealing face against the second sliding face of the second sliding sleeve. 
     In other preferred embodiments, the recess has one or more additional sliding sleeves and the sealing plug is accordingly constructed so that it is also preferably completely in abutment with those sliding faces in the introduced state. 
     Alternatively or additionally to a sealing directly against the sliding faces of the sliding sleeves, a preferred embodiment of the method provides for the first and second sealing faces of the sealing plug to be spaced apart from each other in such a manner that they enclose the sliding sleeve or sliding sleeves between them. 
     Preferably, in the introduced state, at least one of the sealing faces is in sealing abutment with an end portion of the sliding sleeves in the direction of the longitudinal axis. 
     In another preferred embodiment, at least one of the sealing faces, in addition to the sliding sleeves, is in sealing abutment with the recess in an axially spaced-apart or adjacent manner. 
     In another preferred embodiment of the invention, the sealing plug has a base member made of a resiliently deformable material, preferably silicone, or a silicone-containing material. This material selection affords the advantage that the sealing plug has very good resilient deformation properties and additionally after use can be easily cleaned and prepared for reuse. 
     In a further preferred manner, the base member of the sealing plug is in the form of a hollow member with a longitudinal axis and is preferably open in the direction of the longitudinal axis thereof at one or both ends. The configuration as a hollow member facilitates the radial compression of the sealing plug and consequently the introduction thereof into the recess. An open sealing plug, in particular when it is open in both directions, improves the flow of the painting agent in an immersion method and contributes to preventing an undesirable spreading of painting agent and/or other fluids which are required for the painting process into subsequent processing steps, such as, for example, subsequent immersion baths. The (painting and/or other) agent can flow through the sealing plug, whilst the inner face of the recess which is intended to be kept free is protected by the sealing plug in an undiminished manner. Preferably, the sealing plug has around the recess a tapered portion, in a particularly preferred manner a conical tapered portion. The tapered portion makes an undesirable accumulation of fluid in the region of the recess more difficult and thus improves the drainage thereof. 
     In another preferred embodiment, the sealing plug is reinforced in the region of at least one of the ends thereof, wherein the sealing plug preferably has a material thickening and/or a support ring, and wherein, in the step of the introduction, the reinforced end is preferably also introduced into the recess. This improves the retention of the sealing plug inside the recess during the immersion operation or during the painting operation. As mentioned in the introduction, the invention particularly demonstrates its advantages during immersion painting methods, but the protective effect of the sealing plug is equally apparent in spray painting methods. 
     In another preferred embodiment, the method further comprises the steps of: removing the sealing plug after the painting step, cleaning the sealing plug of paint residues, and preparing the sealing plug for reuse in another run-through of the method. 
     The reuse of operating components, such as the sealing plug described herein, contributes to the sustainability of the production process and contributes to the environmental compatibility. 
     The present disclosure has been described above in a first aspect with reference to the method according to the present disclosure. In a second aspect, the present disclosure further relates to a sealing plug for use in the painting method in a component of a vehicle brake, in particular in a method according to one of the preferred embodiments described above, wherein the component has a recess which extends in the direction of a longitudinal axis and which has an inner face which is intended to be kept free from paint. 
     The present disclosure also solves the problem set out in the introduction with regard to such a sealing plug in that the sealing plug is configured to be introduced into the recess of the component and has at least one sealing face—or a sealing face arrangement having a plurality of sealing faces—with an excess dimension with respect to the inner face of the recess so that the sealing face inside the recess can be brought into sealing abutment with the inner face in a radial direction with respect to the longitudinal axis. The term “excess dimension” is intended to be understood in this instance to mean that the sealing plug is pressed together in a radial direction and/or the material thereof is compressed when it is introduced into the recess, in any case in those regions of the base member thereof in which the sealing face or sealing faces is/are formed 
     The sealing plug according to the present disclosure makes use of the same advantages as the method according to the invention. The preferred embodiments of the method are at the same time preferred embodiments of the sealing plug according to the present disclosure, and vice versa, for which reason in order to prevent repetition, reference may be made to the above statements. 
     The present disclosure relates in another aspect to the use of a sealing plug for keeping an inner face of a recess of a component of a vehicle brake free from paint during a painting operation. The use of the sealing plug achieves the object described in the introduction by a sealing plug, which is constructed in accordance with one of the preferred embodiments described above, being used. 
     The use of the sealing plug exploits the same advantages as the method according to the invention and the sealing plug according to the invention. The preferred embodiments of the method and the sealing plug are at the same time preferred embodiments of the use of the sealing plug according to the present disclosure, and vice versa, for which reason in order to prevent repetition reference may be made to the above statements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in greater detail below with reference to the appended Figures and preferred embodiments. In the drawings: 
         FIG.  1    is a perspective view of a component of a vehicle brake, in a state prepared for painting in the method according to the present disclosure, 
         FIG.  2    is cross-sectional view of an embodiment of a sealing plug according to the present disclosure for use in the method according to the present disclosure, 
         FIG.  3    is cross-sectional view of another embodiment of a sealing plug according to the present disclosure for use in the method according to the present disclosure, 
         FIG.  4    is cross-sectional view of another embodiment of a sealing plug according to the present disclosure for use in the method according to the present disclosure, 
         FIG.  5    is cross-sectional view of another embodiment of a sealing plug according to the present disclosure for use in the method according to the present disclosure, 
         FIG.  6    is cross-sectional view of another embodiment of a sealing plug according to the present disclosure for use in the method according to the present disclosure, 
         FIG.  7    is cross-sectional view of another embodiment of a sealing plug according to the present disclosure for use in the method according to the present disclosure, and 
         FIG.  8    is a schematic flow chart of an embodiment of the method of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows, as a portion of a utility vehicle  1 , a component  3  of a brake system of the utility vehicle.  1 , in particular, a brake caliper. In the present embodiment, the component  3  is produced as a cast component but could also be a component produced in a different manner. The component  3  has a base member  4  in which a plurality of recesses  5  are introduced. The recesses  5  are, for example, configured as bolt guides for receiving and linearly guiding bolts for brake liner adjustment. In the left portion of the component  3  in  FIG.  1   , a sealing plug  7  is shown introduced into one of the recesses  5 . A handling portion  8  protrudes from the recess  5 . There are introduced in the handling portion  8  one or more, in this instance two, opposing recesses  10 , by way of which the handling portion  8  can be pressed together in order to facilitate an introduction and removal of the sealing plug  7  into the recess  5  or out of the recess  5 . 
     The sealing plug  7  is retained by way of a clamping force in a radial direction in a substantially frictionally engaging manner in the recess  5 . This will be discussed in greater detail below with reference to a number of different embodiments in the following Figures. 
       FIGS.  2 - 7    show various embodiments of the sealing plug  7 , which correspond to each other in terms of significant basic principles. All the sealing plugs thus have a substantially cylindrical basic shape and may be produced from a silicone-containing material, in particular silicone. The sealing plugs  7  in each case have a sealing face arrangement  11  which can be composed differently in the different variants. However, the sealing face arrangements  11  have in common that, as a result of a slight excess dimension of the sealing plug  7 , they are in sealing abutment in a radial direction against an inner face  9  of the recess  5  and, in a radial direction relative to a longitudinal axis L, apply a clamping force that retains the sealing plug  7  in the recess in a frictionally engaging manner. 
     The recess  5  extends for all embodiments from a first end face  19  to a second end face  21  through the component  3 , and the sealing plugs  7  are introduced into the recess  5  in such a manner that the sealing plugs  7 , at both end faces  19 ,  21 , are not in abutment with the end faces  19 ,  21 , but instead are spaced apart therefrom. 
     The sealing plugs  7   a - 7   e  according to  FIGS.  2  to  6    in each case have a hollow-cylindrical base member  25  which has, at least at one end, a through-opening  17  or at least one radial recess  29  for discharging painting agents, in particular in order to prevent undesirable spreading of painting agents and/or other fluids required for the painting process into subsequent processing steps. 
     The sealing plugs  7   a - 7   e  according to  FIGS.  2 - 6    have, at the end opposite the handling portion  8 , a reinforcement in the form of a material thickening  27 . At the side of the handling portion, one or more engagement elements, for example flaps, which facilitate the withdrawal of the sealing plug after painting, are preferably provided. Preferably, the sealing plug has, in the region of the handling portion, one or more flaps that are configured to facilitate the withdrawal of the sealing plug after painting. 
     By way of example in all embodiments, at least one sliding sleeve, that is to say, in one aspect, a first sliding sleeve  13   a  and a second sliding sleeve  13   b , is inserted in the recess  5 , in particular pressed in. The sliding sleeves  13   a ,  13   b  in each case have a sliding face  15  which forms part of the inner face  9  of the recess  5 . 
     The structural differences and different operating methods of the different sealing plugs  7   a - 7   f  will be discussed below. 
     The sealing plug  7   a  according to  FIG.  2    has a plurality of sealing faces  11   a - 11   e  that are configured to seal the recess  5 . The sealing plug  7   a  thus has a total of three sealing faces  11   a ,  11   c ,  11   e  which are in direct sealing abutment with the inner face  9  of the recess  5 , wherein the sealing faces  11   a ,  11   e  are in each case, in addition to the sliding sleeves  13   a ,  13   b , in abutment with the inner face  9  of the recess  5  and enclose the sliding sleeves  13   a ,  13   b  axially between them. The sealing face  11   a  is directly adjacently in abutment with the sliding sleeve  13   a , whilst the sealing face  11   e , which is arranged at an opposite end from sealing face  11   a , is arranged with axial spacing from the sealing sleeve  13   b . However, a different configuration is also completely conceivable, as will be seen from the other embodiments. Between the sealing faces  11   a  and  11   b , and between  11   d  and  11   e , there is preferably arranged at least one support face which is in particular orientated perpendicularly to the sealing faces and which is supported on the sliding sleeve and which positions the sealing plug inside the recess  5 . 
     The sliding sleeve  13   a  is further located in sealing abutment with a sealing face  11   b , in an end portion  23   a  of the sliding sleeve  13   a . A sealing face  11   d  of the sealing face arrangement  11  is also located in an end portion  23   b  of the sliding sleeve  13   b  in sealing abutment with the sliding sleeve  13   b.    
     Between the sealing faces  11   b ,  11   d  there is arranged another sealing face  11   c  which also brings about an individual closure of the sliding sleeves  13   a ,  13   b  in respective cavities, on the one hand, with the sealing face  11   a  and, on the other hand, with the sealing face  11   e.    
     The sealing plug  7   b  according to  FIG.  3    differs from the sealing plug according to  FIG.  2    in that the sealing face arrangement  11  has a slightly smaller number of sealing faces. The sliding sleeves  13   a ,  13   b  are also enclosed by two terminal sealing faces  11   a ,  11   f , wherein the sealing face  11   a  is constructed and arranged as in  FIG.  2    while, however, the sealing face  11   f  is in sealing abutment with a chamfer  31  in the recess  5 . As can be further seen in  FIG.  3   , the chamfer is slightly recessed relative to the end face  19  of the component  3  so that, in this embodiment, the sealing plug and in particular the sealing faces  11   a - 11   f  are spaced apart from both end faces  19 ,  21 . The hollow-cylindrical base member  25  according to  FIG.  3    is constructed to be continuously uniform at the inner side thereof, but has at the left end portion in  FIG.  3    a radial recess  29  for discharging painting agent. 
     Adjacent to the sealing face  11   a , the sealing plug  7   b  has an additional sealing face  11   b  which is in sealing abutment with the sliding sleeve  13   a  in an end portion  23   a , as already described in  FIG.  2   . 
     The sealing plug  7   c  shown in  FIG.  4    is constructed, with regard to the arrangement of the sealing faces  11   a - 11   f  thereof, in accordance with the sealing plug  7   b  according to  FIG.  3   , for which reason, with respect to identical reference numerals and in order to prevent repetition, reference may be made to the statements above. In contrast to the sealing plug  7   b  of  FIG.  3   , the sealing plug  7   c  has at the left end thereof in  FIG.  4   , that is to say, the end opposite the handling portion  8 , a support ring  32  for additional reinforcement. The support ring  32 , preferably in addition or as an alternative to the material thickening  27 , stabilizes the base member  25  and increases the radial clamping action within the recess  5 . 
     The sealing plugs  7   a  to  7   c  protect, in each case, at both sides of the recess  5  from paint being introduced up to the sliding sleeves  13   a ,  13   b.    
     As a variant to these embodiments, which are particularly suitable for complete immersion of the component  3  in a paint bath, or for painting the component  3  at all sides using other methods,  FIG.  5    sets out a sealing plug  7   d  which is also suitable for such methods in which the entire component  3  is intended to be painted. 
     The sealing plug  7   d  has a sealing face arrangement  11  which is formed at the side of the sealing plug  7   d  opposite the handling portion  8  and at that location has a sealing face  11   a  and two additional sealing faces  11   g ,  11   h . The sealing face  11   a  is used for additional sealing, as a sliding prevention mechanism, and/or for centering. The sealing face arrangement  11  further has the sealing faces  11   g ,  11   h  by which the sealing plug  7   d  primarily and directly seals against the sliding faces  15  of the sliding sleeves. 
     From the right side, an open gap  33  remains in the recess  5  after the sealing plug  7   d  has been introduced so that material could theoretically penetrate at that location, but not as far as the sliding faces  15  of the sliding sleeves. The sealing plug  7   d  is also spaced apart at both end sides  19 ,  21 , even when it is completely introduced. 
     The sealing plug  7   e  shown in  FIG.  6    differs from the previous embodiments of  FIGS.  1  to  4    in that the base member  25  of the sealing plug  7   e  is not only in abutment with sliding sleeves  13   a ,  13   b  in an end region, but the sealing face arrangement  11 , as in  FIG.  5   , in each case has sealing faces  11   g ,  11   h  which, preferably over the entire length of the sliding sleeves  13   a ,  13   b , that is to say, extensively, are in sealing abutment with the sliding faces  15  of the sliding sleeves and in this manner prevent an undesirable coating of the sliding faces  15  of the sliding sleeves within the recess  5 . At the side of the sealing plug  7   e  facing the handling portion  8 , the sealing face arrangement  11  has, in contrast to  FIG.  5   , in turn a conical sealing face  11   f  which seals the chamfer  31 . As in  FIG.  2   , the sealing plug  7   e  has, at the end thereof opposite the handling portion  8 , a through-opening  17 . 
     Whilst in  FIGS.  2  to  6    a single-piece sealing plug  7   b - 7   e  is shown,  FIG.  7    sets out a sealing plug  7   f  which is formed from a first plug portion  35   a  and a second plug portion  35   b . The plug portions  35   a ,  35   b  are operationally connected to each other by a clamping member, for example, by a spindle  37  and a clamping nut  39 , which is supported against a disk  43 , and can produce a clamping force using the clamping member. The clamping movement is transmitted via sleeves  41 ,  42  which are in each case formed in the plug portions  35   a ,  35   b . The clamping of the sealing plug  7   f  within the recess  5  results in the plug portions  35   a ,  35   b , which are produced from a resiliently deformable material, in particular a silicone-containing material or silicone, being moved against the sliding sleeves  13   a ,  13   b  and, when an adequate clamping resistance is reached, being compressed in an axial direction. The axial compression movement leads to the material giving way in a radial direction, whereby the radial sealing and clamping force according to the invention is then produced within the recess  5 . The sealing plug  7   f  according to  FIG.  7    is also spaced apart from both end faces  19 ,  21  and is not in abutment therewith. The component  3  can thus also be completely painted from the outer side with the sealing plug  7   f  according to  FIG.  7   , whilst the recess  5  or the inner face  9  thereof, including the sliding faces  15  of the sliding sleeves  13   a ,  13   b  can be kept completely free from paint. 
     With reference to the method diagram according to  FIG.  8   , the use of the sealing plugs  7  according to  FIGS.  1  to  7    in the method according to the present disclosure will now be explained. 
     A first step  101  represents the beginning of the method. At the beginning of the method, in step  103 , a component of a vehicle brake, in particular a brake caliper for a utility vehicle brake, and a sealing plug  7 , for example, one of the sealing plugs  7   a - 7   f , is provided. 
     In a next method step  105 , the sealing plug  7  is introduced into a recess  5  of the component  3 , wherein the component  3  has an inner face  9  which is intended to be kept free from paint. The sealing plug  7  is introduced in such a manner that the sealing face arrangement  11  thereof, which has at least one sealing face  11   a - 11   h , is in sealing abutment inside the recess  5  in a radial direction against the inner face  9  and thus closes the recess  5  in a paint-tight manner. In a next step  107 , the component  3  is then painted. During the painting, the sealing plug  7  is retained in a frictionally engaging manner by the clamping force of the resiliently deformed material in the recess  5 . 
     After the painting, in step  109 , the sealing plug  7  is removed from the recess  5 , for example, by the sealing plug  7  being pressed together at the handling portion  8  thereof, whereby the base member  25  of the sealing plug  7  at least partially collapses and can be pulled out of the recess  5 . If a sealing plug  7   f  according to  FIG.  7    is used, the radial clamping can be removed by releasing the clamping member  37 ,  39  until removal is possible. 
     After the sealing plug  7  has been removed from the component  3 , the component can be transferred onward in the production sequence and the method can be ended in a step  111 . 
     For the sealing plug  7 , however, the method does not yet have to be ended at this point: in a next method step  113 , the sealing plug  7  is preferably cleaned of paint residues so that in a subsequent method step  115  the sealing plug  7 , which has been prepared in this manner, can be provided again for a method run-through and can be supplied again to the method step  105 . 
     As long as the sealing plug  7  remains undamaged and the resilient deformability thereof is maintained to a sufficient degree, the sealing plug  7  can be used many times in the method according to the present disclosure. 
     LIST OF REFERENCE NUMERALS (PART OF THE DESCRIPTION) 
     
         
           1  Vehicle 
           2  Component 
           3  Base member 
           4  Recess, component 
           7 :  7   a - 7   f  Sealing plug 
           8  Handling portion 
           9  Inner face 
           10  Recess, handling portion 
           11  Sealing face arrangement 
           11   a - 11   h  Sealing face 
           13   a ,  13   b  Sliding sleeve 
           15  Sliding face 
           17  Through-opening, sealing plug 
           19  End face, component 
           21  End face, component 
           23 :  23   a ,  23   b  End portion, sliding sleeve 
           25  Base member, sealing plug 
           27  Thickened portion 
           29  Radial recess, sealing plug 
           31  Chamfer, component 
           32  Support ring 
           33  Gap, component 
           35   a ,  35   b  Plug portion 
           37  Spindle 
           39  Clamping nut 
           41  Sleeve, sealing plug 
           42  Sleeve, sealing plug 
           43  Disk 
           101 ,  103 ,  105 ,  107 ,  109 ,  111 ,  113 ,  115  Method steps 
         L Longitudinal axis