WO2001025645A2

WO2001025645A2 - Roller bearing

Info

Publication number: WO2001025645A2
Application number: PCT/US2000/041041
Authority: WO
Inventors: Hendrik A. Van Egeraat; Jens E. Jacobbson
Original assignee: Pc Vane Inc.
Priority date: 1999-10-04
Filing date: 2000-10-02
Publication date: 2001-04-12
Also published as: AU1495001A; WO2001025645A3

Abstract

A roller cassette (33) is rotatably disposed inside the outer ring (3).

Description

ROLLER BEARING

Prior application

This is a continuation- in-part patent application of U.S. Patent Application Serial No. 09/478,012, filed January 5, 2000.

Technical field

The present invention relates to a roller bearing assembly that even in small sizes accepts both radial and thrust loads .

Background and summary of the invention

Conventional wheel for inline skates use bearings that generate a high friction and do not last very long. A high friction is a particular problem in competitive situations. Another problem with the conventional bearings is that they are difficult to maintain and take apart. Additional, the conventional bearings are often too big, clumsy and heavy to easily and effectively build into hand held tools, inline wheels and other devices. There seems to be a need for a bearing that has a low radial and thrust friction and small dimensions. The bearings should also have a low weight and be easy to integrate in all kinds of equipment .

The bearings of the present invention are easy to dismantle and clean, even sterilize, also making them suitable for medical and food processing equipment. One object of the present invention is to provide a bearing that has the operating characteristics of a double angular contact bearing that is inexpensive relative to its performance. The bearing is also energy efficient especially in view of the small inner diameter of the bearing. The bearing also has a minimal weight to performance ratio and its main components are easy to take apart and maintain. The bearing is suitable for a number of applications including rotation centers of inline skate wheels, hand held power tools and, medical and food processing equipment . The bearing of the present invention has an integrated bearing construction using a roller cassette that reduces the number of parts in the bearing.

The bearing is easy to dismantle, clean (sterilize) and assemble. The bearing reduces the friction of parts that rotate with different radial velocities by synchronizing them.

The present invention comprises a roller cassette that has cylindrical rollers that may be divided in sections having different diameters. The bearing serves the purpose of acting like a double angular bearing, however with fore mentioned reduced friction losses. The cassette including the rollers may, under the spring-action of an integral part of the cassette, be clipped in/out of an outer ring that is in operative engagement with the cassette and other components. Fore mentioned positioning of the cassette might at the same time be used for locating/pre-assembling other parts that are not directly connected to the bearing.

Brief description of the drawings Fig. 1 is a cross-sectional view of the bearing device of the present invention in a wheel;

Fig. la is a detailed cross-sectional view of the bearing device in Fig. 1;

Fig. lb is a detailed cross-sectional view of the bearing device in Fig. 1;

Fig. lc is a detailed cross-sectional view of the bearing device in Fig. 1 ;

Fig. Id is a detailed cross-sectional view of the bearing device in Fig. 1; Fig. 2 is a partial cross-sectional view of a roller cassette that has been partially pulled out of the outer ring; Fig. 3 is a partial perspective view of the roller cassette;

Fig. 4 is a cross-sectional view of the roller cassette in a drill; Fig. 5 is an exploded view of an alternative embodiment of the roller bearing device of the present invention;

Fig. 6 is a perspective view of a component of the roller cassette; Fig. 7 is a side view of a component of the roller cassette;

Fig. 8 is a perspective view of a component of the roller cassette;

Fig. 9 is a perspective view of a roller; Fig. 10 is a side view of the roller in Fig. 9;

Fig. 11 is a cross-sectional side view of the bearing device disposed in a wheel; and

Fig. 12 is a detailed view of an alternative embodiment of a roller disposed in a roller bearing device.

Detailed description

Fig. 1 illustrates a bearing device 60 that has an outer ring 3 secured by molding within a wheel 31. The outer ring 3 may be made from general ball bearing steel and may be hardened under vacuum to up to minimal 45-50 Hrc . After the outer ring 3 is hardened, it may be centerless ground at its outer perimeter 13 (see Fig. lb) to a perfectly round shape. This ensures a perfectly round surface for the clamping of the outer ring 3 under the final production stage that includes finishing the surface 14 and the recess 12, defined in the outer ring 3, by precision machining with special carbide tipped tool, or grinding. A roller cassette 33 that includes rings la, lb may be made from a glass fiber reinforced polyamide. Other suitable materials may also be used. The rings la, lb are attached to one another and holds the rollers 2 therebetween. Inner rings 4 and 5 may be held in their pre-assembled position by small inwardly protruding extensions 17, which are also shown on Fig. 3, of the rings la, lb and can thereby be clicked into or out of the holding position around the rollers 2. One surprising discovery is that the roller device of the present invention does not require any lubrication to work efficiently. Fig. la shows a detailed view of the extension 17 that holds the bearing inner rings 4 and 5 in place in the pre-assembled condition of roller cassette 33.

Fig. lb shows the roller 2 and its different cylindrical parts. The identical cylindrical parts 7 and 8 ' are adapted to roll on the identical outer surfaces 20 and 21 of the bearing inner rings 4 and 5 in a radial velocity of dl/d2 where dl represents the outer diameter of the cylindrical parts 7 and 8 and d2 represents an outer diameter of the rings 4 and 5. The identical cylindrical parts 9 and 10 are adapted to roll on the identical inner surfaces 22 and 23 of the outer ring 3 in a relation D1/D2 where Dl represents the outer diameter of the parts 9 and 10 and D2 represents an inner diameter of the outer ring 3. Preferably, the relation dl/d2 = D1/D2 should exist for the highest efficiency because then the rollers 2 have the same radial velocity in relation to the diameters dl and D2 that is independent of whether the inner bearing rings 4 and 5 or the outer bearing ring 3 are rotated.

Fig. lc shows the fitting of the profiled extension ring 11 of roller 2 within the recess 12 of the outer ring 3. In order to focus the contacts between roller 2 and the outer ring 3 in the near vicinity of the mutual contact curves 24 and 25, the inner surface of the recess 12 and the outside walls of the extension ring 11 form an angle (A) therebetween. Thereby accepting axial loads, while not dispersing the contact area over a number of conflicting diameters. There is a clearance 26 between a bottom of the recess 12 and the top of the extension 11 of the roller 2. Fig. Id shows a diametric contact between an upper rounded corner 27 of the inner ring 4 and a transition area of the cylindrical part 7 and the axial contact between the shoulder 28 of the inner ring 4 and a side wall surface 30 disposed between the parts 7 and 9 of the roller 2. The shoulder 28 and the outer surface 30 have an angular clearance B in order to concentrate all rolling contacts between the radius 27 and a transition area 29 between the parts 7 and 9.

Fig. 2 shows the position of the roller 2 when it has been clicked out of the recess 12 of the outer ring 3 and been moved half way along the inner surface 23 of the outer ring 3. At the start the extension 11 is pushed against the inner wall of the recess 12 of the bearing outer ring 3. The roller 2 is then pushed away from the recess 12 and towards the flexible part 6 diametrically opposite the position of the particular roller 2. The roller 2 may thus be pushed downward in order to fit within the inner surface 23 of the inner ring 3 so that the roller 2 may be pulled out. It may then be put back again in a similar manner.

Fig. 3 shows a detailed view of the roller 2 and oppositely disposed rings la, lb. The ring 6 is also shown against which the rollers 2 may move under pressure to insert or remove the roller 2 from the outer ring 3. Fig. 4 shows a rotating connection of a mandrel 53 of a power drill 51, by using a minimum number of parts. The driving sprocket 52 may drive a gear wheel part 57. The construction may be assembled by pushing a stabilizer 54 into mandrel 53. The roller cassette may then be snapped into a groove 12 of the mandrel 53, while at the same time locking the stabilizer 54 in its pre-assembled position. Then, the whole assembly may be pushed onto a central pivot 55 and fastened by a screw 56.

Fig. 5 is an exploded view of an alternative embodiment of a roller bearing device 100 that has an outer ring 102 and a roller cassette 104 disposed therein.

The outer ring 102 has an outside surface 106 and an inside surface 108. The outside surface 106 has two parallel circumferential grooves 110, 112 extending around the outer ring 102. The inside surface 108 has a central groove 114 defined therein. More particularly, the groove 114 is defined by a bottom wall 116 and two opposite slanting side walls 118, 120 that terminate in transition areas 119, 121, respectively, disposed between the side walls 118, 120 and the bottom wall 116. The inside surface 108 also has chamfered outer edges 122, 124.

The roller cassette 104 has a first holder ring 126 and a second holder ring 128. The ring 126 has a smooth outer side surface 130, a chamfered outer edge 132 and a chamfered inner edge 13 . An inner side surface of the ring 126 has cavities 136a-f defined therein to receive rollers 138.

As best shown in Figs. 6-7, the cavity 136a has opposite rounded side walls 200, 202 and a flat bottom 204 to receive a round outer segment of the roller 138, as explained in detail below. The remaining cavities 136b-f are preferably identical to the cavity 136a. Between the cavities 136a and 136b, an axial female receiver 206 is disposed. The receiver 206 has a triangular-shaped receiver opening 208 defined therein that is facing the same direction as the cavity 136a. The receiver 206 has a radially inwardly directed protrusion 144 that has an inwardly rounded inner surface 210 (see Fig. 7) . The protrusion 144 has flexible outer flanges 212, 214 that may bend to conform to an outer surface of the roller 138. The receiver 206 has rounded side walls 213, 215 that are also adapted to bear against the roller 138, as explained below.

A male protrusion 216 is disposed between the cavities 136b and 136c. The protrusion 216 has a triangular-shaped foot 218 and a round extension 220 that is dimensioned to fit into the receiver opening 208 of the female receiver 206. The extension 220 has a narrowing rounded top 222. For example, the protrusion 216 may be inserted into a receiver 224 of the ring 128, shown in Fig. 8, while a receiver 206 of the ring 126 receives a male protrusion 226 of the ring 128. In this way, the ring 126 may be assembled with the ring 128, as shown in Fig. 5. As best shown in Figs. 9-10, the roller 138 has a larger diameter central segment 230 and outer segments 232, 234 disposed on each side of the segment 230. The segment 230 has a diameter that is greater than a diameter of the segments 232, 234. The segment 230 has a smooth round flat outer surface 236 with chamfered edges 238, 240 on each side thereof with slanting side walls 237, 239. Between the segment 230 and the segment 232, there is a rounded transition area 242 and between the segment 230 and the segment 234 there is a rounded transition area 244. Both the segments 232, 234 have chamfered outer edges 246, 248, respectively.

With reference to Fig. 5, an elongate ring 150 is disposed inside the roller cassette 104. The ring 150 has a central outwardly radially protruding circumferential extension 152 on an outer surface 154 of the ring 150. The extension 152 has a chamfered upper edge 156 and a rounded transition area 158 between the extension 152 and the surface 154. The ring 150 has opposite outer end protrusions 160, 162 that are slightly thicker than the rest of the ring 150 so that the outer diameter is increased slightly at the protrusions 160, 162 and so that support surfaces 161, 163 are formed between the protrusion 160 and the extension 152 and between the protrusion 162 and the extension 152, respectively. The protrusion 160 has a chamfered surface 164 and the protrusion 162 has a chamfered surface 166. The ring 150 has an axial groove 168 defined at the end 160.

A first holder 170 and a second holder 172 are snapped into the support surfaces 161, 163, respectively. The first holder 170 has a smooth inner surface 174 and a thick inner section 176 and a thin outer section 178. More particularly, the surface 174 has an inner surface 175 and an outer surface 177 that are separated by a transitional shallow groove 181 so that the outer surface 177 has a slightly larger inner diameter. The section 176 has an inner edge 180 that has a first chamfered surface 182 followed by a second chamfered surface 184. The inner edge 180 also has an inside chamfered edge 183. Similarly, the second holder 172 has a smooth inner surface 186 and a thick inner section 188 and a thin outer section 190. More particularly, the surface 186 has an inner surface 187 and an outer surface 189 that are separated by a transitional shallow groove 191 so that the outer surface 189 has a slightly larger inner diameter. The surface 189 also has a chamfered edge 193.

The section 188 has an inner edge 192 that has a first chamfered surface 194 followed by a second chamfered surface 196. The inner edge 192 has an inside chamfered edge 195 and the section 190 has an outer chamfered edge 198. The section 178 also has an outer chamfered edge 179.

Fig. 11 shows the bearing device 100 mounted in a wheel 250. The device 100 is assembled and the outer ring 102 is secured to a wheel component 252. The roller cassette 104 is disposed inside the outer ring 102 so that the central segment 230 of the roller 138 is positioned in the central groove 114 of the outer ring 102 and so that the roller 138 and the outer ring 102 are rotatable relative to one another. More particularly, the chamfered edges 238, 240 of the roller 138 bear against transition areas 119, 121 of the outer ring 102 that are disposed between the bottom wall 116 and the two side walls 118, 120, respectively. The segment 230 is also positioned between the first and second holders 170, 172 so that the transition areas 242, 244 of the slanting side walls 237, 239 may bear against the chamfered surfaces 182, 184 of the holder 170 and against the chamfered surfaces 194, 196 of the holder 172. The holders 170, 172 may be in contact with the rotatable roller 138 at the transition areas 242, 244 thereof, respectively, for minimal friction between the surfaces .

The rings 126, 128 each has an inwardly protruding outer wall 254, 256, respectively, that is disposed between outer segments 232, 234 of the roller 138 so that the roller 138 is rotatable relative to the rings 126, 128.

The holder 172 is placed on the outer surface 154 of the ring 150 so that the inner edge 195 thereof rotatably bears against the transition area 158 between the extension 152 and the outer surface 154. The outer protrusion 162 bears against the groove 191 of the outer surface 189 to hold the holder 172 in place on the ring 150. The holder 170 is held to the ring 150 in the same way. In this way, the holders 170, 172 are held to the ring 150 while being rotatable relative to the ring 150 and the roller 138. A screw 258 having an axle 260 may extend through the ring 150 that, in turn, may be held by a nut 262. An important feature of the present invention is the ease of removing and inserting the holders 170, 172, the ring 150 and the cassette 104 into the outer ring 100 secured to the wheel 250. For example, the holder 172 may be removed by axially pulling it out from the ring 150 because the protrusion 162 disposed in the shallow groove 191 holds the holder 172 in place while permitting the holder 172 to be pulled out from the ring 150 when the protrusion 162 is forced out of the shallow groove 191. When the holder 172 is pulled out, it is easy to slide out the ring 150 in the opposite direction by pulling out the holder 170 that is now lose. The cassette 104 may then be axially pulled out also because the rollers 138 are radially movable within the openings 136. By axially pulling or pushing the entire cassette 104, the rollers 138 slide radially inwardly within the openings 136 as a result of the rollers 138 moving along the sloping inner walls 118, 120 of the central groove 114 of the outer ring 102. Because the protrusion 144 is resilient, like a spring, the rollers 138 are permitted to deform the protrusions 144 as the rollers move radially inwardly. In this way, the flat outer surface 236 of the segment 230 is flush with outer surfaces 253, 255 of the rings 126, 128, respectively, so that the outer surfaces 236, 253, 255 may slide against inner surfaces 257 or 259 of the outer ring 102 depending on which direction the cassette 104 is shifted.

Similarly, the cassette 104 may easily be put back into operational position by pushing the cassette 104 along the inner surfaces 257 or 259 until the segment 230 snaps into the groove 114. The ring 150 is then inserted into the holder 172 until the chamfered surfaces 194, 196 abuts the transition area 158 of the ring 150. The ring 150 is held to the holder 172 because the protrusion 162 extends into the shallow groove 191 of the holder 172. The ring 150 and the holder 172 are then together inserted into the cassette 104 until the inner edge 192 abuts the transition area 244 at the side 239 of the roller 138. Similarly, the holder 170 is inserted into the cassette from the opposite side until the inner edge 183 of the holder 170 abuts the transition area 242 of at the surface 237 of the roller 138. The protrusion 164 of the ring 150 prevents the holder 170 from falling out of the cassette 104. The screw 258 is then inserted with the axle 260 through the ring 150 and tightened at the other side by the note 262.

During operation of the wheel 250, the ring 150 and the holders 170, 172 are stationary. The cassette 104 may rotate relative to the ring 150 and the holders 170, 172. The rollers 138 may also rotate relative to the ring 150, the holders 170, 172 and the cassette 104. Finally, the outer ring 102 may rotate relative to the cassette 104, the rollers 138 and the ring 150.

Because the contact surface between the holders 170, 172 and transition areas 242, 244 of the roller 138 is very small, there is very little friction between the rotating surfaces. Also, because the contract surface between the edges 238, 240 of the roller 138 and the edges 118, 120 of the groove 114 is small, there is very little friction.

Fig. 12 shows a portion of an alternative embodiment of the present invention. Instead of having a roller with a central segment that has a diameter that is greater than the diameter of the outer segment, the central segment may have a small diameter. More particularly, a roller bearing device 300 has an outer ring 302 with a central protrusion 304 that protrudes into a central cavity 306 of a roller 308. Similarly to the embodiment described above, the alternative embodiment has a first holder 310 and a second holder 312 that rotatably engage outer segments 314, 316 of the roller 308. A portion of a cassette 320 is disposed between the outer segments 314, 316. While the present invention has been described in accordance with preferred compositions and embodiments, it is to be understood that certain substitutions and alterations may be made thereto without departing from the spirit and scope of the following claims .

Claims

We claim :

1. A roller bearing device, comprising: a first ring-shaped holder having a first chamfered surface; an elongate sleeve having a radially outwardly protruding central protrusion, the first holder being rotatably attached to a first side the elongate sleeve; a second ring-shaped holder, the second holder being rotatably attached to a second side of the elongate sleeve, the second side being opposite the first side, the second ring-shaped holder having a second chamfered surface; an outer ring having a central groove defined by a bottom wall and two opposite first and second slanting side walls, the outer ring having an inner surface, the outer ring having a first transition area disposed between the bottom wall and the first slanting side wall and a second transition area disposed between the bottom wall and the second slanting side wall; a roller having a central segment and two opposite first and second outer segments, the central segment having a first and a second chamfered edge, the first chamfered edge being in rotational engagement with the first transition area of the outer ring and the second chamfered edge being in rotational engagement with the second transition area of the outer ring, the roller having a first rounded area disposed between the first outer segment and the central segment and a second rounded area disposed between the second outer segment and the central segment; the first rounded area in rotational engagement with the first chamfered surface of the first ring-shaped holder, the second rounded area being in rotational engagement with the second chamfered surface of the second ring-shaped holder; a first holder device having a first flange disposed between the first outer segment of the roller and the inner surface of the outer ring, the first holder having a first cavity defined therein for rotatably receiving the first outer segment of the roller, the first holder device having a radially inwardly extending protrusion and a first outer surface; a second holder device having a second flange disposed between the second outer segment of the roller and the inner surface of the outer ring, the second holder device having a second cavity defined therein for rotatably receiving the second outer segment of the roller, the second holder device having a second outer surface; and the roller being radially inwardly movable from a first position disposed inside the central groove of the outer ring to a second position against the radially inwardly extending protrusion of the first holder device so that the central segment of the roller is flush with the first outer surface of the first holder device and the second outer surface of the second holder device .

2. The roller bearing device according to claim 1 wherein the outer ring is secured to a wheel.

3. The roller bearing device according to claim 1 wherein the first holder device is attached to the second holder device .

4. The roller bearing device according to claim 1 wherein the central segment has a first diameter and the outer segment has a second diameter, the first diameter is greater than the second diameter.

5. The roller bearing device according to claim 1 wherein a gap is formed between the central protrusion of the elongate sleeve and the central segment of the roller.

6. The roller bearing device according to claim 1 wherein the first ring-shaped holder is rotatable relative to the roller and the first holder device.

7. A method of dismantling a roller bearing device, comprising:

(a) providing a first ring-shaped holder having a first chamfered surface, an elongate sleeve having a radially outwardly protruding central protrusion, a second ring-shaped holder having a second chamfered surface, an outer ring having a central groove defined by a bottom wall and two opposite first and second slanting side walls, the outer ring having an inner surface, the outer ring having a first transition area disposed between the bottom wall and the first slanting side wall and a second transition area disposed between the bottom wall and the second slanting side wall, a roller having a central segment and two opposite first and second outer segments, the central segment having a first and a second chamfered edge, the first chamfered edge being in rotational engagement with the first transition area of the outer ring and the second chamfered edge being in rotational engagement with the second transition area of the outer ring, the roller having a first rounded area disposed between the first outer segment and the central segment and a second rounded area disposed between the second outer segment and the central segment, the first rounded area being in rotational engagement with the first chamfered surface of the first ring- shaped holder, the second rounded area being in rotational engagement with the second chamfered surface of the second ring-shaped holder, a first holder device having a first flange disposed between the first outer segment of the roller and the inner surface of the outer ring, the first holder having a first cavity defined therein for rotatably receiving the first outer segment of the roller, the first holder device having a radially inwardly extending protrusion and a first outer surface, a second holder device having a second flange disposed between the second outer segment of the roller and the inner surface of the outer ring, the second holder device having a second cavity defined therein for rotatably receiving the second outer segment of the roller, the second holder device having a second outer surface; (b) axially pulling the first ring-shaped holder in a first direction from the elongate sleeve; (c) axially pulling the elongate sleeve and the second ring-shaped holder in a second direction that is opposite the first direction; and (d) axially pulling the roller cassette from the outer ring.

8. The method according to claim 7 wherein step (d) further comprises moving the roller radially inwardly along the slanting side wall of the outer ring and deforming the radially inwardly extending protrusion of the first holder device.

9. The method according to claim 8 wherein the method further comprises moving the roller radially inwardly until the central segment of the roller is flush with the first outer surface of the first holder device.