MX2008008659A - An asymetrical k-ring - Google Patents

Abstract

A system and method for an asymmetric K-ring is disclosed. The system and method is for forming a K-ring with the dynamic sealing surface (514) closer to one edge or face (506) of the k-ring than the other edge or face (504) . The asymmetrically placed dynamic sealing surface creates a largerbevel (510) on one side of the K-ring thereby reducing the sealing force produced by the K~ring when pressure is applied to the side of the K-ring with the larger bevel .

Description

K ASYMMETRIC RING FIELD OF THE INVENTION The invention relates to the field of the closure rings, and in particular, to an asymmetric K-ring.

BACKGROUND OF THE INVENTION Closing rings come in many varieties. An example of closing rings, of the best known, is the O-ring. Another type of closure ring is the K ring. The K ring was originally developed by the Knorr-Bremsen Company (also known as the Knorr-Breaks Company). The original ring K was used in the driving mechanisms of the air brakes. The K rings have two variations, the first type moves with the piston (see figure a) and the second type is captured by the cylinder (see figure Ib). Figure 2 is a cross-sectional view of the ring K 200 of the first type. The K-rings, typically, have two closed edges 202, a left face 204, a right face 206, a cavity 208 formed in the inner diameter of the K-ring, a left bezel 210, a right bezel 212, and a closing surface dynamic 214. The left and right bevels 210 and 212, form an angle a with respect to the left and right faces 204 and 206. The angle a is approximately 50 degrees. The dynamic closing surface Ref. = 194177 214 forms a radius of approximately 0.2 mm. Other angles and other radii can be used. The current K rings are symmetrical around a central AA line. K-rings are usually made of a flexible material, such as rubber or silicone. Figure 3 is a sectional view showing the general principles for the way a ring works K. The ring K in figure 3 is a ring K of the first type (that is, the K ring moves with the piston). Figure 3 comprises a piston 302 with a locking ring groove 304, a cylinder wall 306, and a ring K 308 installed in the groove of the locking ring 304. While a pneumatic or hydraulic pressure is applied to the right side of the piston , as represented by the arrow 310, the ring K is forced against the left side of the groove of the closing ring. The pressure, as represented by the arrow 312, also penetrates under the closing edge and fills the cavity formed in the inner diameter of the ring K. This pressure (312) creates a force 314 that pushes the ring K against the wall of the cylinder 306. The pressure applied to the right side of the ring K (310) also interacts with the bevel 316 on the outside diameter of the ring K, creating a force 318 that pushes K ring away from the cylinder wall, counteracting the force 314 Because the area of the cavity formed in the inner diameter of the ring K is greater than the area of the bevel 316, the force 314 is greater than the force 318. The difference between force 314 and 318 is the closing force, due to the pressure, applied by the K-ring against the cylinder wall. Even with force 318, which counteracts force 314, the closing force can still be too large and create undesirable friction between the piston and the cylinder wall. Another problem with the current rings K is the distribution of the closing force through the dynamic closing surface. Figure 4 is a diagram of the closing force between the cylindrical surface and the dynamic closing force. Figure 4 shows a ring K 402 which is pushed against cylinder wall 406. Curve 420 represents the force between ring K 402 and cylinder wall 406. The pressure gradient 422 on the right side is more pronounced than the pressure gradient 424 on the left side. The difference in the pressure gradients, the magnitude of the total pressure, and the gradient of the pressure gradient 422 can cause the K-ring to break the lubrication film from the cylinder wall 406. This can increase wear and reduce the life of the K ring. Therefore, a better K ring is required.

SUMMARY OF THE INVENTION A system and method for an asymmetric K-ring are described. The system and method is to form a ring K with the dynamic closing surface closest to one flange or face of the K-ring that the other flange or face. The asymmetrically placed dynamic locking surface creates a larger bevel on one side of the K-ring, thereby reducing the closing force produced by the K-ring when pressure is applied to the side of the K-ring with the larger bevel. One aspect of the invention includes, a ring K having a first face and a second face opposite the first, a first bevel formed on the first face and a second bevel formed on the second face, wherein the first and second bevel they meet and form a dynamic closing surface placed between the first and second faces, characterized by: the asymmetrically placed dynamic closing surface between the first and the second face, whereby the first bevel is greater than the second. Preferably, the ring K has one of the faces identified visibly as the pressure side of the ring K. Preferably, the ring K has the pressure side of the ring K corresponding to the first surface. Preferably, the ring K has the first face on the left side of the ring K. Preferably, the ring K has the first face on the right side of the ring K.

Preferably, the ring K has the dynamic sealing surface on an outer diameter of the ring K. Preferably, the ring K has the dynamic sealing surface on an inner diameter of the ring K. Preferably, the ring K has the first bevel that forms a angle with the first face of approximately 40 degrees. Preferably, the ring K has the dynamic closing surface forming a radius of about 0.6 mm. Another aspect of the invention comprises a method for making the ring K, characterized by: molding the location of the dynamically closing surface asymmetrically between the first and second faces, thereby causing the first bevel to be greater than the second. Preferably, a method for using the ring K, characterized by: pressurizing the first face; Preferably, a method for using the ring K, characterized by: pressurizing the second face. Another aspect of the invention comprises a ring K, characterized by: a means for reducing the radial pressure exerted by the ring K when a fluid force is applied to the first side of the ring K.

Another aspect of the invention comprises a ring K, characterized by: a means for increasing the radial pressure exerted by the ring K when a fluid force is applied to the first side of the ring K.

BRIEF DESCRIPTION OF THE FIGURES Figures Ia-Ib are a sectional view of the two types of K-rings (Prior art). Figure 2 is a sectional view of a ring K showing the different parts of a ring K. Figure 3 is a sectional view showing the general principles on how the ring K works. Figure 4 is a diagram of the force of closing between the surface of the cylinder and the dynamic closing surface. Figure 5 is a cross-sectional view of the asymmetric ring K in an exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Figure 5 and the following description detail the specific examples that teach those skilled in the art how to make and use the best mode of the invention. For the purposes of teaching the inventive principles, some conventional aspects have been simplified or omitted. The experts will appreciate variations of these examples that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific examples, described below, but only by the claims and their equivalents. Figure 5 is a cross-sectional view of the asymmetric ring K in an exemplary embodiment of the invention. The ring K 500 has two closing edges 502, a left face 504, a right face 506, a cavity 508 formed in the inner diameter of the ring K, a left bevel 510, a right bevel 512, and a dynamic closing surface 514 The bevel 510 forms an angle of approximately 40 degrees with the left face 504. The dynamic closing surface 514 forms a radius of approximately 0.6 mm. The dynamic closing surface 514 is no longer placed symmetrically around the center line AA, but closer to the right face 506 of the ring K than on the left side 504. By moving the dynamic closing surface 514 closer to the side 506 of the ring K a larger bevel 510 is created on one side of the ring K than the bevel 512 on the other side of the ring K. In an exemplary embodiment of the invention, when the dynamic closing surface 514 moves closer to the FACE 506, the bevel 512 can only be formed as part of the radius forming the dynamic closing surface 514. Another exemplary embodiment of the invention, when the dynamic closing surface 514 is only unadjusted from the center line AA by a minimum amount, the bevel 512 it can start as part of the radius forming the dynamic closing surface 514 and then merge with a straight segment ending at the surface 506. In operation, when the pressure is applied to the left face 504 of the ring K 500, the pressure interacts with the bevel 510 which causes the force 518. The pressure also interacts with the cavity 508 that causes the force 514. The force 514 causes the ring K to push against the cylinder wall (not shown) and force 518 counteracts force 514 which reduces the surface pressure that ring K applies against the cylinder wall. Because the dynamic closing surface 514 is closer to the surface 506, the bevel 510 is larger than a corresponding bevel in a symmetrical K-ring. Because the 510 bevel is larger, the 518 force is too. The greater force 518 more counteracts the force 514, thus reducing the total pressure that the K-ring applies to the cylinder wall.

When the pressure is applied to the right face 506 of the ring K 500, the pressure interacts with the bevel 512 that causes the force 518. The pressure also interacts with the cavity 508 that causes the force 514. The force 514 causes the ring K pushing against the cylinder wall (not shown) and the force 518 counteracts the force 514 which reduces the pressure of the ring K that is applied to the cylinder wall. Because the dynamic closing surface 514 is closer to the face 506, the bevel 512 is smaller than a corresponding bevel in a symmetrical K-ring. Because bevel 512 is smaller, force 518 is smaller. The smaller force 518 counteracts minus the force 514, thereby increasing the total pressure that the K-ring applies to the cylinder wall. By moving the dynamic locking surface towards or away from the side of the K-ring where the pressure is applied, the closing force between the K-ring and the cylinder wall can be increased or reduced. For a K ring designed to reduce the closing force, there would be two different directional rings. A K-ring designed to be used with the pressure applied to the left face of the K-ring (as shown in Figure 5) and a K-ring designed to be used with the pressure applied to the right face of the K-ring (not shown). A K ring designed to increase the closing force would also have two distinct directional K-rings. The dynamic closure surface can be moved to different positions between the center line and one face of the ring, depending on how much one wishes to reduce a force or how much one wants a force to increase.

Because the K-ring is asymmetric, a visible identification can be added to one side of the K-ring to indicate which face is the pressure face. For example, a mark or a short phase that can be molded or stamped on the side of the K ring that is designed as the pressure side. Other types of visible identification can be used, for example a different color can be used to indicate the pressure side. The examples described above use the type of ring K that moves with the piston. The asymmetric K-ring can also be used as the type captured by the cylinder.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (14)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A ring K having a first face and a second face opposite the first face, a first bevel formed on the first face and a second face bevel formed on the second face, wherein the first and second bevel meet and form a dynamic closing surface positioned between the first and second faces, characterized in that: the dynamic closing surface is asymmetrically placed between the first face and the second face. second face, whereby the first bevel is larger than the second bevel. The ring K according to claim 1, characterized in that it has one of the faces visibly identified as the pressure side of the ring K. 3. The ring K according to claim 1, characterized in that it has the pressure side of the K ring corresponding to the first face. The ring K according to claim 1, characterized in that it has the first face on the left side of the ring K. 5. The ring K according to claim 1, characterized in that it has the first face on the right side of the ring K. 6. The ring K according to claim 1, characterized in that it has the dynamic closing surface in an outer diameter of the ring K. 7. The ring K according to claim 1, characterized in that it has the dynamic closing surface in an inner diameter of the ring K. 8. The ring K according to claim 1, characterized in that it has the first bevel that forms an angle with the first face of approximately 40 degrees. 9. The ring K according to claim 1, characterized in that it has the dynamic closing surface forming a radius of about 0.6 mm. A method for producing a ring K according to claim 1, characterized in that: the location of the dynamically closing surface is asymmetrically molded between the first and the second face, thus causing the first bevel to be greater than the first one. second. 11. A method for using the ring K according to claim 1, characterized in that: the first face is pressurized. 12. A method for using the ring K according to claim 1, characterized in that: the second face is pressurized. 13. A ring K, characterized in that: it has a means for reducing the radial pressure exerted by the ring K when a fluid force is applied to the first side of the ring K. 14. A ring K, characterized in that: it has a means for increasing the radial pressure exerted by the K-ring when a fluid force is applied to a first side of the ring K.