Steering bearing assembly for wheeled vehicle

Abstract: A steering bearing assembly is provided for connecting the front wheel and handle bars (15) of a bicycle to the frame (17). The assembly includes a steerer tube (33), connected to the front wheel and passing through a head tube (21) on the frame. Bearing assemblies on the upper and lower ends of the head tube allow the steerer tube (33) to pivot within the head tube (21). The upper bearing assembly has a first race connected to the head tube (21) and a second race having a tapered contact surface. Above the second race on the steerer tube (33) is a compression ring (67) having a gap (69) so the ring can be compressed against the steerer tube. The connector (35) of a stem (37) is located on the steerer tube (33) above the compression ring (67). The handle bars of the bicycle are connected to the stem. An adjuster nut (79) is threaded into the upper end of the steerer tube, exerting a downward force on the connector (35) and the compression ring (67). The second race compresses the compression ring, locking the upper bearing assembly in place on the steerer tube. The connector is then clamped onto the steerer tube.

Description: Background of the invention 1. Field of the invention The invention relates to a steering bearing assembly according to the preamble of claim 1. In general this invention relates to wheeled vehicles, such as bicycles, and in particular to an assembly for connecting the front wheel and handle bars to the frame of the wheeled vehicle. 2. Description of the Prior Art In some prior art bicycles, e.g. US 4,323,263 A the front wheel and the handle bars are connected to a steerer tube. The steerer tube passes through a head tube connected to the bicycle frame. Ball bearing assemblies, located at the upper and lower ends of the head tube, allow the steerer tube to pivot within the head tube. The upper end of the steerer tube is threaded externally. An internally threaded lock nut is placed on the steerer tube and tightened until the lock nut secures the upper race of the upper bearing assembly downward against the lower race. Unfortunately, this assembly is difficult to adjust with respect to preload on the bearings. Further, the prior art assembly includes a multiplicity of components which renders it unnecessarily complicated and heavy. Most types of bicycling, such as mountain biking, racing, and free-style biking can cause the lock nut to become loose in a very short time. Also, the manufacture of such assemblies is relatively expensive. Other shortcomings are apparent to those skilled in the art. The object therefore is to create an assembly that allows a simple and secure location of the steering bearing assembly with respect to the steerer tube under an adjustable axial loading of the steering bearing assembly. Summary of the invention According to the invention this object is solved by the features of the characterizing part of claim 1. A steering bearing assembly that comprises a compression ring is shown in FR 2 346 203 A. This known compression ring, however, has a bi-conical outer surface that causes troubles with respect to a clear and simple location of the bearing assembly. Preferable embodiments of the invention are claimed in the subclaims. The compression ring of the invention is located on the steerer tube above the second race. The compression ring has a tapered contact surface that abuts the contact surface on the second race. The compression ring also has one or more gaps, or is suitably elastic, so that the ring can be compressed against the steerer tube. An adjuster nut having external threads is threaded into internal threads in the upper end of the steerer tube. As the adjuster nut is threaded inward, the nut exerts a longitudinal force on the compression ring. The tapered contact surface on the compression ring exerts a longitudinal force and a radial force on the second race. In reaction, the second race exerts equal and opposite forces on the compression ring. The compression ring is compressed into the steerer tube, thus locking the compression ring to the steerer tube. Brief Description of the Drawings FIG. 1 is a side view of the front end of a bicycle incorporating the steering bearing assembly of the invention. FIG. 2 is an exploded view of the steering bearing assembly of the invention. FIG. 3 is a sectional view of the steering bearing assembly of the invention, as seen along line 3-3 in FIG. 1. FIG. 4 is a enlarged view of a portion of the steering bearing assembly shown in FIG. 3. Description of the Preferred Embodiment The steering bearing assembly of the invention is intended for use on wheeled vehicles. FIG. 1 shows the invention in use on a bicycle 11, although the invention would also be useful on a tricycle. FIG. 1 shows the front wheel 13, the handle bars 15, and the forward portion of the bicycle frame 17. The bicycle frame 17 has a horizontal top tube 19, welded to a head tube 21. A down tube 23 extends downward and rearward from the head tube 21, below the top tube 19. A pair of fork blades 25 and 27 are bolted to the axle bolt 29 of the front wheel 13. The upper ends of the fork blades 25 and 27 are connected to a fork crown 31. A steerer tube 33 extends upward from the fork crown 31, as shown in FIGS. 2 and 3. The steerer tube 33 passes through the head tube 21 and through a connector 35 on one end of a stem 37. The connector 35 is clamped to the steerer tube 33 with a pair of bolts 39 and 41, so the stem 37 can be replaced or adjusted. The handle bars 15 pass through a second connector 43 on the other end of the stem 37. The second connector 43 has a bolt 41, so the handle bars 15 can be replaced or adjusted. Thus, the handle bars 15 are connected to the front wheel 13, so that the front wheel 13 can be turned by turning the handle bars 15. The steerer tube 33 must be secured relative to the head tube 21 for rotational movement only with respect to the head tube 21 when the handle bars 15 are turned. Thus, there is a lower bearing assembly 47 and an upper bearing assembly 49 between the steerer tube 33 and the head tube 21. As shown in FIG. 3, the lower bearing assembly 47 has a first race 51 and a second race 53. A plurality of ball bearings 55 are enclosed between the first and second races 51 and 53. The first race 51 of the lower bearing assembly 47 is press fit into the lower end of the head tube 21, so the that the first race pivots with the head tube 21. The second race 53 of the lower bearing assembly 47 is press fit into the steerer tube 21, so that the second race 53 pivots with the steerer tube 33. The first and second races 51, 53 are supported to rotate relative to each other by the ball bearings 55. The upper bearing assembly 49 is located at the upper end of the head tube 21. The upper bearing assembly 49 also has a first race 57 and a second race 59, encasing a plurality of ball bearings 61. The first and second races 57, 59 are supported to rotate relative to each other by the ball bearings 61. The first race 57 of the upper bearing assembly 49 is press fit into the upper end of the head tube 21, so that the first race 57 pivots with the head tube 21. The second race 59 of the upper bearing assembly 49 has an annular contact surface 63, best shown in FIG. 4. The annular contact surface 63 is tapered at an angle to the longitudinal axis 65 of the steerer tube 33, shown in FIG. 3. An annular compression ring 67 is located above the upper bearing assembly 49. The compression ring 67 has a small gap 69, as shown in FIG. 2, so that the ring 67 can be compressed. The compression ring 67 also has an upper surface 71, an inner surface 73, and a tapered contact surface 75. The contact surface 75 is tapered at the same angle, relative to the longitudinal axis of the steerer tube 33, as the contact surface 63 on the second race 59 of the upper bearing assembly 49. The contact surface 75 on the compression ring 67 abuts the contact surface 63 on the second race 59. The upper surface 71 of the compression ring 67 abuts the lower end of the connector 35 on the stem 37. The upper end of the steerer tube 33 has internal threads 77, as shown in FIGS. 2 and 3. An adjuster nut 79, having external threads 81, is threaded into the upper end of the steerer tube 33. The adjuster nut 79 has a head 83 that contacts the upper end of the connector 35 on the stem 37. The connector 35 extends above the upper end of the steerer tube 33, leaving a gap between the head 83 of the adjuster nut 79 and the steerer tube 33, as shown in FIG. 3. In assembly of the steering bearing assembly of the invention, the head tube 21 is placed over the steerer tube 33, with the upper bearing assembly 49 on the upper end of the head tube 21. The compression ring 69 is then placed on the steerer tube 33 above the upper bearing assembly 49. Next, the connector 35 of the stem 37 is positioned on the steerer tube 33, above the compression ring 69. When all of the elements are in place, the adjuster nut 79 is threaded into the upper end of the steerer tube 33. As the adjuster nut 79 is threaded, the head 83 of the adjuster nut 79 contacts the upper end of the connector 35 on the stem 37, and forces the connector downward on the steerer tube 33. In turn, the connector 35 exerts a downward force on the upper surface 71 of the compression ring 67. As the compression ring 67 is forced downward, the contact surface 75 on the compression ring 67 exerts a longitudinal force and a radial force on the contact surface 63 of the second race 59 of the upper bearing assembly 49. In reaction, the second race 59 exerts equal and opposite forces on the compression ring 67. The compression ring 67 is compressed against the steerer tube 33, locking the compression ring 67 in place on the steerer tube 33. The head tube 21 and the two bearing assemblies 47 and 49 are secured between the fork crown 31 and the connector 35. Finally, the bolts 39 and 41 on the connector 35 are tightened to secure the stem 37 to the steerer tube 33. When the connector 35 is secured to the steerer tube 33, the connector 35 does not exert any upward forces on the adjuster nut 79. The steering bearing assembly of the invention has several advantages over the prior art. The design of the invention allows the stem 37 to be clamped directly to the steerer tube 33, so the connection is lighter and stronger than prior art designs. Further, the assembly of the invention is easier to assemble and to adjust. Also, since there are no forces acting on the adjuster nut 79, the nut 79 is less likely to loosen. Additionally, the internal threads 77 in the steerer tube 33 are not located in a high stress area of the steerer tube. Further, the assembly allows for a secure connection of the steerer tube relative to the head tube without lateral "play" or movement. Over all, a bicycle embodying the invention is lighter, stronger, and less expensive than the prior art. The invention has been shown in only one embodiment. It should be apparent to those skilled in the art that the invention is not so limited, but is susceptible to various changes and modifications without departing from the scope of the invention. For example, a variety of means may be implemented to provide radial and longitudinal forces between the second bearing and the steerer tube. Such may form a portion of the connector 35 or be provided as a separate component. The compression ring 67 may include multiple gaps or segments and be constructed of a combination of elastic and rigid components, or an elastic compound. It is understood that the assembly may be arranged such that the location of the bearing assembly is inverted, or placed on the other end of the head tube. Other variations will be apparent to those skilled in the art.

Claims: A steering bearing assembly, comprising: a head tube (21) connected to a vehicle frame (17); a steerer tube (33) connected between a wheel (13) and vehicle handle bars (15) and passing through the head tube (21); a bearing assembly (49, 47) to allow the steerer tube (33) to pivot within the head tube (21), the bearing assembly (49, 47) having a first race (57) and a second race (59), the first race (57) being connected to the head tube (21); force means (79, 35, 67, 75, 63, 73) for exerting a longitudinal force on the second race (59) toward the first race (57), characterized in that, the steerer tube (33) has a smooth outer surface that is free of external threading; the second bearing race (59) is carried with clearance with respect to the steerer tube (33); said force means (79, 35, 67, 75, 63, 73) comprises a compression ring (67) having a contact surface (75) tapered at an angle to the longitudinal axis (65) of the steerer tube (33) for contacting a corresponding tapered contact surface (63) on the second race (59), wherein only said part of the force transmitting area of the compression ring (67) that is arranged to contact the second bearing (59) is tapered, whereby said compression ring (67) exerts said longitudinal force and a radial force between the steerer tube (33) and the second race (59); means (79, 35, 71) for exerting a longitudinal force on the compression ring (67); and said force means (79, 35, 67, 75, 63, 73) acts through said compression ring (67) at least on the second bearing race (59) so as to force the second race (59) toward the first race (57). A steering bearing assembly as defined in claim 1, wherein the means (79, 35) for exerting a longitudinal force on the compression ring (67) further comprises an adjuster nut (79) threaded to the steerer tube (33). A steering bearing assembly as defined in claim 2, further comprising: a stem (37) for connecting said handle bars (15) to the steerer tube (33); a connector (35) on one end of the stem (37), wherein the steerer tube (33) passes through the connector (35) and wherein the connector (35) is located between the adjuster nut (79) and the compression ring (67); and a bolt (39, 41) for clamping the connector (35) to the steerer tube (33). A steering bearing assembly as defined in claim 2, wherein the adjuster nut (79) has external threads (81) and is threaded into internal threads (77) on the steerer tube (33). A steering bearing assembly as defined in one of the claims 2 to 4, wherein the compression ring (67) has a gap so that the compression ring (67) is compressed against the steerer tube (33) as the adjuster nut (79) exerts the longitudinal force. A steering bearing assembly according to one of the claims 1 to 5, wherein the force means (79, 35, 67, 75, 63, 73) acts on the smooth surface of the steerer tube (33) as well as on the second race (59) so as to force the second race (59) toward the first race (57) and to fix the second race (59) of the bearing assembly (49) on the steerer tube (33). A steering bearing assembly according to one of the claims 2 to 5, or claim 6, when dependent on claim 2, wherein the inner diameter of the second bearing race (59) being greater than the outer diameter of the steerer tube (33); said compression ring (67) is disposed on the second bearing race (59) and is engaged in the clearance between the second bearing race (59) and the steerer tube (33); said compression ring (67), when engaged in the clearance between the second bearing race (59) and the steerer tube (33) fixing the second bearing race (59) to the steerer tube (33) in a manner providing rotational support therefor; said adjuster nut (79) being axially displaceable toward said stem (37) and acting to simultaneously axially retain the stem (37) on the steerer tube (33) and to force the compression ring (67) toward the second bearing race (59) so as to firmly engage the compression ring (67) between the second bearing race (59) and the steerer tube (33). A steering bearing assembly according to claim 7, wherein the compression ring (67) is directly wedged between an inner surface (63) of the second bearing race (59) and an outer surface (73) of the steerer tube (33) so as to eliminate all play therebetween under the action of said adjuster nut (79).

Inventors: RADER HOMER JOHN, RADER, HOMER JOHN
Applicants: RADER HOMER JOHN, RADER, HOMER JOHN
Application year: 1991
Main classification: B62K21
IPC codes: B62K21