Patent Publication Number: US-2022212513-A1

Title: Circlip, arrangement and method for installing the circlip

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage Patent Application of International Patent Application No. PCT/EP2020/054043, filed Feb. 17, 2020, which claims the benefit of German Application Serial No. 10 2019 109 286.8, filed Apr. 9, 2019, the contents of each are incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The invention relates to a retaining ring for securing a component, to an arrangement which comprises the retaining ring, and to a method for installing the retaining ring. 
     BACKGROUND 
     So-called circlips are known in the prior art, and are used for the positive, axial fixation of components. They are typically made of spring steel wire, and can be opened to allow disassembling the installed, secured component. However, in conditions where tolerances are problematic, or at high loads, retaining rings can undesirably loosen. It is possible to provide a locking mechanism that would prevent the retaining ring from opening, using additional components. However, such locking mechanisms are not able to prevent improper disassembly. Additional components or additionally integrated geometry elements are required for this purpose. 
     SUMMARY 
     It is therefore the object of the present invention to provide a retaining ring by means of which improper disassembly can be prevented, and by means of which misuse can be indicated by unavoidable damage to the component during disassembly. 
     This object is achieved by the retaining ring according to claim  1 , by the arrangement according to claim  12 , and by the method according to claim  14 . Advantageous configurations of the retaining ring and the arrangement are the subject of the dependent claims. 
     The retaining ring according to the invention is used to secure a component against improper disassembly, and comprises a ring segment which has an outer circumference for fixing the retaining ring in the axial direction, and a recess extending along a circumferential direction of the ring segment, and comprises a closure element for closing off the recess, wherein the ring segment forms a contact surface in order to fix the component in the axial direction, and wherein the retaining ring has a locking device for locking the closure element in the recess, which is concealed at least on a side of the retaining ring facing away from the contact surface. 
     Within the meaning of the invention, a component to be secured can in particular be a component that is used in an air spring or an air spring strut, such as a switching valve or a cover of a strut support bearing or strut head bearing. 
     The outer circumference of the ring segment is advantageously suitable for positively fixing the ring segment in the axial direction; however, a non-positive fixing can also be contemplated. The recess in the ring segment is used to compress the ring segment to a smaller diameter (hereinafter referred to as the installation diameter) for installation. After the installation of the ring segment, it opens outward again due to the spring-back forces, or it is opened by a device. The closure element can then be inserted into the recess of the ring segment. The closure element is also advantageously designed as a ring segment. The ring segment and the closure element particularly advantageously form a circumferentially closed ring element after the closure element has been inserted. The closure element advantageously extends along the circumference of the ring element over an angular range of at most 90°, particularly advantageously at most 60°. The cross sections of the closure element and the ring segment can be different in design. 
     Since the locking device is concealed at least on the side of the retaining ring facing away from the contact surface, it cannot be accessed when in the installed state. The locking device is also advantageously concealed on the inside of the retaining ring, such that the locking device cannot be accessed from there either. This prevents improper disassembly, and the misuse can be seen because of the visible damage, since the locking device can no longer be accessed after the installation of the ring segment and closure element, and consequently the closure element can no longer be removed without destruction. This prevents the retaining ring from being disassembled and reinstalled without any visible damage which could indicate misuse. 
     The locking device is advantageously concealed by the closure element and/or the ring segment on the side of the retaining ring facing away from the contact surface and/or on the inside of the retaining ring. 
     In an advantageous embodiment, the locking device is provided on the closure element. This can be done by providing a molded part that is integrated into the closure element. Alternatively, the locking device can be integrated into the ring segment. 
     The ring segment and the closure element are advantageously connected to each other by means of a snap-on connection. The locking device is particularly advantageously designed as a catch spring. A snap-on connection is a type of connection that enables particularly easy installation of the retaining ring, since the connection is established automatically when the closure element is inserted, without the need for further installation steps. In addition, the snap-on connection constitutes a stable form of connection that can absorb forces that occur during operation. Without the closure element, these operating forces could lead to compression of the ring segment, as a result of which it could jump out of the housing and lose its intended safety function. The snap-on connection must be designed in such a way that it has flexible properties in the installation direction—that is to say, it enables installation of the closure element. If the locking device designed as a catch spring is concealed on the side of the retaining ring facing away from the contact surface, it is not accessible when the retaining ring is installed, such that the snap-on connection cannot be released without damaging the retaining ring. 
     In an advantageous embodiment, the closure element and the ring segment are designed as separate individual parts. Alternatively, the closure element can be pivotably connected to the ring segment. The closure element can preferably be connected to the ring segment by an integral hinge. The retaining ring thus comprises few individual parts, and allows a simple installation. 
     In an advantageous embodiment, the outer circumference of the retaining ring has a projection for engaging in a recess of a housing. The projection can be circumferential, that is to say extend over the entire outer circumference, be interrupted, or only be provided at certain points. In particular, the projection can be designed in such a way that it can engage in a housing groove. The projection is used for axial fixation and securing against the retaining ring jumping out of the housing. For this purpose, the projection preferably has a stiffening region and/or the ring segment has stiffening ribs. 
     The closure element and/or the ring segment are advantageously made of a plastics material. A plastics material offers a high degree of freedom in the design of components, which prevents an unnoticed, improper opening of the ring. 
     In an advantageous embodiment, a ratio of a length (L) in the axial direction of the ring segment to a height (H) of the ring segment is between 0.5 and 5. The ratio is particularly advantageously between 0.75 and 2.5. The height of the ring segment is defined as half the difference between the outer diameter and the inner diameter. The length corresponds to the extension of the ring segment in the axial direction. The specified ratios lead to a high geometrical moment of inertia against torsion, since the length of the ring segment in the axial direction is approximately as great or greater than its height. 
     A ratio of an inner diameter of the ring segment to the height is advantageously at least 3, that is to say the inner diameter corresponds to at least three times the height. The ratio is particularly advantageously at least 4. This ensures advantageous resilience to allow compressing the ring segment for installation, while the ring can also snap positively into an outer guide. 
     In an advantageous embodiment, a ratio of the length to the inner diameter of the ring segment is at least 1:8. The ratio is particularly advantageously at least 1:6. 
     The ring segment has advantageous torsional stiffness because the cross section of the ring segment has the highest possible moment of inertia in relation to torsion, but at the same time a reduction in the overall diameter during installation is still possible without destruction. As such, the closure element cannot be removed by bending or twisting the retaining ring as a whole. Due to the advantageous proportions of length, height and inner diameter of the ring segment, it is sufficiently torsion-resistant to be able to transmit high axial forces. As a result, no further supporting structures with the task of preventing twisting of the retaining ring, and thus undesired disassembly, are necessary. 
     The arrangement according to the invention comprises a housing and a component which is secured in the housing by the retaining ring. The retaining ring is advantageously fixed in the axial direction in the housing by means of its outer circumference, preferably in a positive manner, and rests with the contact surface on the component in order to fix the component in the axial direction. 
     The method according to the invention for installing a retaining ring comprises the following steps: 
     Providing a housing, in which a component is arranged, and providing the retaining ring, wherein the recess is not closed off, 
     Compressing or contracting the ring segment in order to elastically reduce an outer diameter of the ring segment to an installation diameter, 
     Inserting the ring segment into the housing in such a way that the contact surface rests against the component, in order to fix it in the axial direction, 
     Releasing the ring segment, such that it springs back to the outer diameter and is fixed in the housing in the axial direction by means of its outer circumference, preferably in a positive manner, and 
     Closing off the recess by means of the closure element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in more detail below with reference to embodiments, which are shown schematically in the drawings, wherein: 
         FIG. 1  is a perspective view of the retaining ring according to the invention, according to a first embodiment; 
         FIG. 2  is a perspective view of the retaining ring according to the invention, according to a second embodiment; 
         FIG. 3  is a perspective view of the retaining ring of  FIG. 2 , with a switching valve; 
         FIG. 4  is a cross-sectional view of the retaining ring according to the invention, according to a third embodiment; 
         FIG. 5  is a cross-sectional view of the retaining ring according to the invention, according to a fourth embodiment, with a switching valve and a housing; and 
         FIG. 6  is a cross-sectional view of the retaining ring according to the invention, according to a fifth embodiment, with a switching valve and a housing. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 and 2  each show a retaining ring  10  for a component  11 , which in the present case is a switching valve. The retaining ring  10  has a ring segment  13  and a closure element  15  which are made of a plastics material. A recess  14 , which extends along a circumferential direction U of the ring segment  13 , and an outer circumference  16  are provided on the ring segment  13 . A circumferential projection  20 , which forms a support shoulder  22 , is attached to the outer circumference  16 . Furthermore, the ring segment  13  has a contact surface  17  for fixing a component. 
     The closure element  15  is used to close the recess  14 . In the embodiment according to  FIG. 1 , the closure element  15  and the ring segment  13  are designed as separate individual parts, while in  FIG. 2  the closure element  15  is pivotably connected to the ring segment  13  by a integrated hinge  19 , for example. 
     The closure element  15  has a locking device  18  for locking the closure element  15  in the recess  14 , which in the present embodiment is designed as a catch spring, such that the ring segment  13  and the closure element  15  can be connected by means of a snap-on connection. The snap-on connection is designed in such a way that it has flexible properties in the installation direction—that is to say, it enables installation of the closure element  15 . 
       FIG. 3  shows the retaining ring  10  in the installed state on the component  11 . The retaining ring  10  is attached to the component  11 , the closure element  15  closing the recess  14 . The closure element  15  is also designed as a ring segment, such that the ring segment  13  and the closure element  15  form a circumferentially closed ring element, wherein the cross sections of the closure element  15  and the ring segment  13  can differ. 
     The locking device  18  is concealed by the closure element  15  and the ring segment  13  on the side of the retaining ring  10  facing away from the contact surface  17 , and on the inside of the retaining ring  10 . The locking device  18  is thus inaccessible from these sides. 
       FIGS. 5 and 6  show a cross-sectional view in which a housing  12  is also shown. This view shows that the locking device  18  in the installed state is concealed by the component  11  and the housing  12  on the outside of the retaining ring  10  and on a side facing the contact surface  17 . This prevents improper disassembly, since after the installation of the ring segment  13  and the locking element  15 , the locking device  18  can no longer be accessed and the locking element  15  can consequently no longer be released without destroying or visibly damaging the retaining ring  10 . 
     The snap-on connection thus represents a suitable connection design for preventing improper disassembly, which also enables particularly easy installation of the retaining ring  10 , since the connection is established automatically when the closure element  15  is inserted without further installation steps being required. Finally, the forces that occur during operation can be reliably absorbed by the snap-on connection, thereby preventing the retaining ring  10  from jumping out of the housing  12  in an undesired manner. 
       FIG. 4  shows a cross section of the ring segment  13 . A ratio of a length L in the axial direction A of the ring segment  13  to a height H of the ring segment is advantageously between 0.5 and 5, particularly advantageously between 0.75 and 2.5. The height H of the ring segment is defined as half the difference between the outer diameter DA and the inner diameter DI. The length L corresponds to the extension of the ring segment  13  in the axial direction A. The specified ratios lead to a high geometrical moment of inertia against torsion, since the length L of the ring segment in the axial direction A is approximately as great or greater than its height H. 
     A ratio of the inner diameter DI of the ring segment  13  to the height H is advantageously at least 3, particularly advantageously at least 4. This ensures a resilience that is sufficient to compress the ring segment  13  made of a plastics material for installation without damage. 
     A ratio of the length L to the inner diameter DI of the ring segment  13  is advantageously at least 1:8, particularly advantageously at least 1:6. 
     The ring segment  13  has high torsional stiffness because the cross section of the ring segment  13  has the highest possible geometrical moment of inertia with respect to torsion, but at the same time a reduction in the overall diameter during installation is still possible without destruction. As such, the closure element  15  cannot be removed by bending or twisting the retaining ring  10  as a whole. Due to advantageous ratios of length L, height H and inner diameter DI of the ring segment  13 , it is sufficiently torsion-resistant to be able to transmit high axial forces. In addition, the provision of stiffening regions  23  and/or stiffening ribs (not shown) improves the rigidity of the retaining ring  10 . In addition, no further supporting structures with the task of preventing twisting of the retaining ring  10 , and thus undesired disassembly, are necessary. 
       FIGS. 5 and 6  show the arrangement of the retaining ring  10 , with the component  11  and the housing  12 . It can be seen in this case that the component  11  is secured in the axial direction A by the retaining ring  10 , since it rests against the contact surface  17  and is thus fixed in the axial direction A. A support shoulder  22  formed on the outer circumference  16  rests against a housing wall in order to prevent the retaining ring  10  from being jammed. The projection  20  of the retaining ring  10  engages in a recess  21  of the housing  12 , which in the present case is designed as a circumferential housing groove, such that the retaining ring  10  is fixed in a form-fitting manner in the axial direction A in the housing  12 . 
     In the installation of the retaining ring  10 , the ring segment  13  is first compressed or contracted in order to elastically reduce the outer diameter DA of the ring segment  13  to an installation diameter. Then the ring segment  13  is introduced into the housing  12  in such a way that the contact surface  17  rests against the component  11  in order to fix it in the axial direction A. The ring segment  13  is then released so that it springs back to the outer diameter DA, and is fixed in a form-fitting manner in the axial direction A in the recess  21  of the housing  12  by means of the projection  20  attached to the outer circumference  16 . Finally, the recess  14  is closed off by means of the closure element  15 . 
     The retaining rings  10  according to these embodiments prevent improper disassembly and have a high degree of rigidity, in particular high torsional rigidity.