CA2279896C - Pulley assembly having molded connection - Google Patents
Pulley assembly having molded connection Download PDFInfo
- Publication number
- CA2279896C CA2279896C CA002279896A CA2279896A CA2279896C CA 2279896 C CA2279896 C CA 2279896C CA 002279896 A CA002279896 A CA 002279896A CA 2279896 A CA2279896 A CA 2279896A CA 2279896 C CA2279896 C CA 2279896C
- Authority
- CA
- Canada
- Prior art keywords
- component
- radially
- annular
- outer component
- pulley
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/32—Friction members
- F16H55/36—Pulleys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/14467—Joining articles or parts of a single article
- B29C45/14491—Injecting material between coaxial articles, e.g. between a core and an outside sleeve for making a roll
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/68—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by incorporating or moulding on preformed parts, e.g. inserts or layers, e.g. foam blocks
- B29C70/84—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by incorporating or moulding on preformed parts, e.g. inserts or layers, e.g. foam blocks by moulding material on preformed parts to be joined
- B29C70/845—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by incorporating or moulding on preformed parts, e.g. inserts or layers, e.g. foam blocks by moulding material on preformed parts to be joined by moulding material on a relative small portion of the preformed parts
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C13/00—Rolls, drums, discs, or the like; Bearings or mountings therefor
- F16C13/006—Guiding rollers, wheels or the like, formed by or on the outer element of a single bearing or bearing unit, e.g. two adjacent bearings, whose ratio of length to diameter is generally less than one
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C35/00—Rigid support of bearing units; Housings, e.g. caps, covers
- F16C35/04—Rigid support of bearing units; Housings, e.g. caps, covers in the case of ball or roller bearings
- F16C35/06—Mounting or dismounting of ball or roller bearings; Fixing them onto shaft or in housing
- F16C35/07—Fixing them on the shaft or housing with interposition of an element
- F16C35/077—Fixing them on the shaft or housing with interposition of an element between housing and outer race ring
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C2045/1486—Details, accessories and auxiliary operations
- B29C2045/14868—Pretreatment of the insert, e.g. etching, cleaning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/32—Wheels, pinions, pulleys, castors or rollers, Rims
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C19/00—Bearings with rolling contact, for exclusively rotary movement
- F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
- F16C19/04—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly
- F16C19/06—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly with a single row or balls
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2204/00—Metallic materials; Alloys
- F16C2204/50—Alloys based on zinc
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2220/00—Shaping
- F16C2220/02—Shaping by casting
- F16C2220/06—Shaping by casting in situ casting or moulding
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2226/00—Joining parts; Fastening; Assembling or mounting parts
- F16C2226/30—Material joints
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2361/00—Apparatus or articles in engineering in general
- F16C2361/63—Gears with belts and pulleys
Abstract
A process for manufacturing a pulley assembly comprising the steps of providing an outer component (12) having a central opening with an inner surface. An inner component (10) having an outer wall is provided. The inner component is disposed in the central opening. The inner and outer components define a molten material receiving space therebetween. Molten material is then injected into the space. The molten material is allowed to solidify and form a locking element (70) having radially extending portions providing axial movement of the inner and outer components relative to one another.
Description
WO 98!34053 PCT/CA98/00063 _1_ _.
PULLEY ASSEMBLY HAVING MOLDED CONNECTION
The present invention relates generally to a pulley assembly having an improved connection between a radially outer component and a radially inner component.
The invention relates more particularly to a pulley assembly having an improved molded connection between a pulley structure and a bearing assembly.
In particular the present invention provides a molded structural connection between the pulley and bearing that is simple to accomplish, improves the strength of the connection, is inexpensive to implement, and allows an inexpensive pulley structure component to be utilized.
Conventionally, glue or other similar adhesives have been used to connect a pulley structure to the outer race of a ball bearing assembly in a typical pulley assembly. When glue or other similar adhesives are used, there must be a thin or non-existent gap between the outer race of the ball bearing assembly and the pulley structure in order to obtain a sufficiently strong adhesive bond. In conventional practice, a phenolic pulley is molded and placed about the outer surface of the ball bearing assembly while in an expanded and heated state.
Glue is then inserted into the gap between the pulley structure and the ball bearing assembly. The pulley structure then shrinks as it cools to close the gap therebetween. Thus, as the pulley structure shrinks the glue adheres the surfaces of the ball bearing assembly and the pulley structure together.
However, in this conventional practice, there are stringent dimensional and tolerance requirements necessary to prevent (a) warpage of the ball bearing assembly caused by over-shrinkage of the phenolic pulley structure and (b) insufficient bonding of the phenolic pulley structure to the ball bearing assembly caused by a large gap formed by under-shrinkage of the pulley structure. Furthermore, even when these stringent dimensional and tolerance requirements are met it is still desirable to have a means of bonding the two components together which is stronger than the bonding afforded by glue or other similar adhesives.
Therefore, it is an object of the present invention to provide a process for manufacturing a pulley assembly which obviates the problems described above with the conventional practice of adhering components to one another. The process according to the present invention comprises the steps of providing an outer component of a pulley assembly having a central opening. The outer component has an inner surface surrounding the central opening. An inner component of the pulley assembly is provided having an outer surface.
The inner component is mounted within the central opening of the outer component. The _2_ _.
inner and outer component define a molten material receiving space therebetween. Molten material is then injected into the space. The molten material is cooled and forms a locking element. The locking element has radially extending portions providing axial movement limiting surfaces constructed and arranged to prevent axial movement of the outer component and the inner component relative to one another.
It is a further object of present invention to provide a pulley assembly comprising an outer component having a central opening. The outer component has an inner surface surrounding the central opening. An inner component has an outer wall and is disposed within the central opening of the outer component. A locking element has radially extending portions on opposing sides thereof providing axial movement limiting surfaces constructed and arranged to prevent axial movement of the outer and inner components relative to one another.
It is also a further object of the present invention to provide a pulley assembly comprising an outer component having a central opening. The central opening has an inner surface surrounding the central opening. An inner component has an outer wall. The inner component is disposed within the central opening of the outer component. A locking element is formed from solidified molten material and has radially extending portions providing axial movement limiting surfaces constructed and arranged to prevent axial movement of the inner and outer components relative to one another.
~1Z1FF DESORTPTION OF. THE DR.AWING~
2o Figure 1 is a cross sectional view of a ball bearing assembly prior to assembly in accordance with the principles of the present invention;
Figure lA is a cross sectional view of a pulley structure prior to assembly in accordance with the principles of the present invention; ' Figure 2 is a cross sectional view of the ball bearing assembly and pulley structure disposed in a lower die mold prior to an injection molded connection being provided to connect the ball bearing assembly with the pulley structure;
Figure 3 is a cross sectional view similar to the view shown in Figure 2, but further d showing an upper die mold disposed in a lowered position during an injection molding operation;
Figure 4 is a cross sectional view of a pulley assembly according to the principles of the present invention;
Figure 4A is a cross sectional view of the injection molded connection of Figure 4.
Figures 5-? are cross sectional views taken through the injection molded connection for connecting the ball bearing assembly to the pulley structure in,accordance with the'principles of the presentinvention.
Figure 8 is a cross sectional view similar to Figure 4 showing an alternative embodiment of a pulley assembly according to the principles of the present invention.
Figure 1 and lA are cross sectional views of an inner component in the form of a ball bearing assembly, generally indicated at 10, and an outer component in the form of a pulley structure, generally indicated at I2, prior to such components being connected to one another.
The ball bearing assembly 10 is conventional and includes an annular inner steel race 14, an annular outer steel race 16, and a plurality of steel ball elements 18 disposed therebetween.
The inner race 14 has an exterior surface comprising a substantially cylindrical surface portion and radially outwardly flared arcuate surface portions 22 and 24 extending from opposite ends of the cylindrical surface portion 20. Similarly, the outer race 16 has an exterior surface 15 comprising a main cylindrical surface portion 30, and arcuate surface portions 32 and 34 extending radially inwardly from opposite ends of the cylindrical wall portion 30. Each of the arcuate surface portions 22, 24, 32 and 34 are arcuate about a 1 mm radius, as is the case with most conventional ball bearings suited for the present application.
The pulley structure 12 has a generally annular construction. In particular, the pulley 20 structure 12 has a generally cylindrical peripheral wall portion 36 having a plurality of radially outwardly facing and circumferentially extending ribs 40 separated by a plurality of circumferendally extending grooves 42. The alternating ribs 40 and grooves 42 form what is known as a poly-V configuration constructed and arranged to engage associated ribs and grooves of a poly-V timing or accessory drive belt. The present invention is not limited to such type of pulley structures, but contemplates that the outer cylindrical wall portion 36 may have a smooth cylindrical outer surface constructed and arranged to engage the flat side of a timing or drive belt.
The pulley structure 12 further includes a radially extending wall portion 44 integrally formed with the cylindrical wall portion 36. The radially innermost portion of the wall portion 44, and hence of the pulley ~cture I2, constitutes an annular connecting portion 46 constructed and arranged to be connected with the radially outer periphery or outer race of the ball bearing assembly I0. It should be appreciated that while the wall portion 44 may take the _ q, _ _ form of a complete annular ring, it may'instead comprise a plurality of radially extending tab portions or spoke-like plates connecting the annular connecting portion 46 with the cylindrical wall portion 36.
The connecting portion 46 has a slightly greater thickness than the wall portion 44 and includes a radially innermost annular surface 48 of slightly greater diameter than the outer cylindrical surface portion 30 of the outer race 16.
It should be noted that the annular surface 48 has somewhat of a convex configuration. In the embodiment shown in Figures 1-S, this convex configuration is provided by a substantially cylindrical surface portion 45, and annular edges 47 and 49 (also referred to as inner edge to portions) which extend from opposite ends of the surface portion 45 at an obtuse angle of about 165 degrees with respect to the surface portion 45 as viewed in cross section:
In Figure 2, the pulley structure 12 and ball bearing assembly I O are shown mounted in a lower die part, generally indicated at 50. Together, the upper die part 60 and the lower die part 50 define a die assembly. The lower die part SO has a central interior pin 52 having an exterior diameter slightly smaller than the diameter of the inner cylindrical seuface portion 20The exterior configuration of pin 52 is constructed and arranged to form a close fit with the inner cylindrical surface portion 20 of the inner race 14: The lower die part 50 also includes a vertically extending cylindrical interior wall 54 having a diameter slightly greater than the outer diameter of the pulley structure 12. The cylindrical wall 54 is thus constructed and arranged to be disposed in close fitting engagement with peripheral portions of the cylindrical wall 36 of the pulley structure 12. The pin 52 and cylindrical wall 54 serve as locating elements for accurately positioning the pulley structure I2 relative to ball bearing assembly 10 in the lower die part 50 so as to maintain an annular gap or molten material receiving space 100 which provides relatively constant distance between the outer cylindrical wall portion 30 of the ball bearing assembly 10 and the inner annular surface 48 of the pulley structure 12.
Preferably, as will be described in greater detail later, this annular gap 100 is between .025 inches -.030 inches wide.
A~ can be appreciated from Figure 3, an upper metal die part 60 is lowered until it comes into forced engagement with the uppermost portion of the upwardly facing annular edge 47 (or 49 if inverted) of the pulley structure 12 and ball bearing assembly 10. As a result of this forced 3o engagement, a pair of downwardly facing radially spaced annular sealing surface portions of the upper die part 60 form radially spaced annular seals with the uppermost annular portion of the connecting portion 46 (or the uppermost portion of the upwardly facing annular edge 47 of such WO 98!34053 PCT/CA98l00063 connecting portion 46) and with the uppermost portion of the outer race's edge (or the uppermost portion of the upwardly facing arcuate surface portion 32 of such race's edge). The aforementioned forced engagement forces the ball bearing assembly 10 into forced engagement with the lower die part 50 in similar fashion. Particularly, radially spaced, upwardly facing annular sealing surface portions of the lower die part 50 form radially spaced annular seals with the lowermost portion of connecting portion (or the lowermost portion of the downwardly facing annular edge 49 of such connecting portion) and with a lowermost downwardly facing annular portion of the outer race {or the lowermost annular portion of the downwardly facing arcuate surface portion 34 of such race).
l0 The upper metal die part 60 has a plurality of circumferentially spaced pin holes 66 (also referred to as injecting holes) in the lower surface thereof between the downwardly facing radially spaced annular surface portions of the metal die,part forming the respective annular seals with the uppermost annular portion of the connecting portion {or of the upper annular surface 47 of the connecting portion) and the uppermost annular portion of the outer race 16 (or uppermost annular portion of arcuate surface portion 32 thereof). The pin holes 66 are positioned to inject an appropriate molten material into the sealed annular gap formed between the pulley structure 12 and ball bearing assembly Z 0.
Preferably, the molten material used is a zinc/aluminum alloy, such as ZA3 or ZAS alloy, or Accu-zinc. It is also possible to use substantially pure zinc, pure lead or glass-filled nylon.
The preferred molten zinc alloy beneficially has a low melting point and need only be heated to a temperature of between 825°-850° F.
Preferably, a pulley made from phenolic material is used, although steel, aluminum, zinc, or plastic pulleys are also possible. Phenolic is preferable because it is relatively inexpensive, and also because it absorbs heat at a relatively slow rate (i.e., in comparison with other possible materials), thus preventing the molten material from freezing or solidifying before it completely fills the sealed space or gap between the pulley structure 12 and ball bearing assembly 10.
Additional advantages of a phenolic pulley are noted later.
For a phenolic pulley, the gap 100 is preferably about .025 inches and no smaller than .020 inches wide to prevent freezing of the molten substance prior to the gap being completely filled. A smaller gap would accommodate a smaller amount of molten material;
which would in turn having a corresponding smaller thermal mass. In addition, the smaller the gap; the greater the percentage of molten material will be in contact with the surrounding metal surfaces. Thus, _ 6 . _. _ smaller gaps cause faster solidification of the molten material:
It should be noted that it is possible to prevent freezing from occurring with gaps of less than .02 inches by heating the pulley and ball bearing assembly during the injection molding process. However, this is not preferred, as heating of parts may cause some degradation thereof.
Where materials other than phenolic are used for the pulley structure 12 (e.g.
steel), a gap thicker than 0.25 inches is preferably used between the pulley structure 12 and ball bearing assembly 10 to prevent freezing. A still thicker gap must be used for an aluminum pulley. It should be noted, however, that irrespective of the pulley material, it is preferable to maintain a gap of less than .04 inches, because after the molten material solidifies, it tends to grab the ball bearing assembly by the outside diameter (as will be described in greater detail later) which may have a tendency to slightly deform the outer race 16. The greater the gap, the more force will be applied by the greater mass of solidified molten material, and the outer race 16 will be deformed to a greater extent as a result. Such deformation may have an undesirable effect on the ball bearing assembly 10.
Referring now to Figure 4, it can be appreciated that the sealed gap between the ball bearing assembly 10 and pulley structure 12, as well as the resultant solidified material therebetween, has a generally bow-tie cross-sectional configuration. In particular, the solidified material forms an annular locking wedge or element, generally indicated at 70, which has a cross sectional configuration that includes a cylindrical wall portion 72, and outwardly flared portions 74 and 76 or wedges at opposite ends thereof. The ball-bearing assembly side of the cylindrical wall portion 72 forms a cylindrical inner surface portion 78 which has a substantially similar configuration to the adjacent exterior surface 30 of the outer race 16 as a result of the injection-molding process: Similarly, the pulley side of the wall portion 72 forms a cylindrical outer surface portion 80 which is substantially similar in configuration to the adjacent cylindrical surface portion 45 of the pulley structure 12 as a result of the injection-molding process. The outwardly flared portions 74 and 76 of the annular locking wedge 70 are formed as a result of the convexly formed edges 47,49 of the connecting portion 46 of the pulley structure 12, and the convexly formed arcuate surface portions 32, 34 of the outer race 16.
The outwardly flared portion 74:includes a radially inwardly extending portion 75 and a radially outwardly extending portion 77. Similarly, the outwardly flared portion 76 includes a radially inwardly extending portion 79 and a radially outwardly extending portion 81.
It should be appreciated that inwardly extending portions 75, 79 have respective concave WO 98134053 ' PCT/CA98100063 surfaces portions (axial movement limiting surfaces} 82, 84 extending from opposite ends of the cylindrical surface portion 78 on the ball bearing side of the locking wedge 70. These arcuate surface portions 82, 84 have an arcuate configuration of an approximately 1 mm radius, matching the radius of the convex arcuate surface portions 32, 34 of the outer race 16. The radially outwardly extending portions 77 and 81 have respective angled surfaces (axial movement limiting surfaces) 86 and 88 which extend from opposite ends of cylindrical surface 80 at an angle with respect thereto. More particularly, the surface 80 has a generally straight cross-sectional configuration, and the opposite surface portions 86 and 88 extend at an angle of approximately 165° with respect to the straight surface 80. The configuration of surface 80 conforms substantially to the adjacent surface 45 of the connecting portion 46, while surfaces 86 and 88 respectively conform to edge portions 47 and 49 of the connecting portion 46.
It should be noted that as the injected molten material solidifies, it undergoes a slight shrinkage that assists in mechanically locking the pulley structure 12 to the ball bearing assembly l0. This will be described in greater detail with reference to Figures 5-7.
As shown in Figure 5, the locking wedge or element 70 shrinks in a longitudinal or axial direction by a distance D when comparing its configuration when cast at 750°F to its configuration at an operating temperature of 175°F. This longitudinal shrinkage causes the outwardly flared opposite longitudinal ends 74, 76 to apply a gripping force which mechanically grips the opposite edges of the outer race 16 and the opposite edges of the connecting portion 46, thus mechanically locking the pulley structure I2 to the ball bearing assembly 10. At the same time, a slight shrinkage of the cross-sectional width of the wall portion 72 by a distance X
which is substantially smaller than D, but nevertheless provides a slight clearance between the opposite surfaces 78 and 80 of the wall portion 72 and the respective adjacent surfaces 30 and 45 of the ball bearing assembly 10 and pulley structure I2. This slight clearance between the wall portion 72 and adjacent surfaces of the pulley structure 12 and ball bearing assembly 10 is advantageous in that less stress is applied by the locking wedge 70 o the central, more vulnerable portions of the outer race 16 and connecting portion 46.
It is also contemplated, though not preferable, that the locking wedge 70 will permit rotational movement of the pulley structure 12 and the ball bearing assembly I
O relative to one another. However, it is preferred that such relative rotational movement be prevented.
It is also contemplated that a plurality of grooves (not shown) may be provided on either the innermost annular surface 48 of the pulley structure 12 or main cylindrical surface portion WO 98J34053 PCTICA98t00063 _g_ 30 of the ball bearing assembly 10, or both. As such, one or more groove engaging portions {not shown) corresponding to the one or more gmoves will be formed on the locking wedge or element 70 as it is cooled. These groove engaging portions engage the corresponding one or more grooves to prevent axial movement between the ball bearing assembly 10 and the pulley structure 12.
As noted above, the annular surface 48 of the pulley structure 12 preferably has a convex configuration which forms a corresponding concave configuration on the adjacent portions of locking wedge 70. In particular, surface portions 86, 80, and 88 of the locking wedge 70 together form a concave surface. It is preferred that the surface portions 86 and 88 form an obtuse angle of approximately 165 ° with respect to surface 80 and have a length of about 3 mm.
In another embodiment, the inner convex surface of the pulley is formed by two annular surfaces which are angled with respect to one another and meet at a mutual boundary point. As a result, as shown in Figure 6; an annular locking wedge 90 will be formed having a concave surface 94 comprising a pair of angled surface portions 96 snd 98 as shown. The configuration shown in Figure 6 causes a more uniform load to be applied to the pulley after shrinking of the wedge.
Figure 7 is a variation of the embodiment shown in Figure 6. Figure 7 shows an annular locking wedge 98 having an arcuate surface 104 adjacent the pulley which has a substantially smoothly formed concave configuration. As with the previous embodiments, the surface i04 is constructed and arranged to be disposed in locking geometric relation with a correspondingly 2o formed, smooth convex configuration of the inner annular surface of the associated pulley structure. In this configuration, the load on the pulley is greatest at the peripheral portions of the surface 104 and is zero at the center.
It should be appreciated that the surfaces 80, 94; and 104 of the respective embodiments of Figures 5, 6, and 7 each take a configuration which is substantially dictated by the particular configuration of the inner annular surface (e.g. annular surface 48 'of the first embodiment) of the pulley structure 12. Thus, the load on the pulley structure 12 can be modified in accordance with the particular configuration of the inner annular surface of the pulley structure 12:
It should also be appreciated that the opposite concave surface of the locking wedges 70, 90, and 98 have substantially the same configuration as one another and is dictated by the same 3o conventional ball bearing assembly used with each.
It is preferable that the pulley structure 12 be molded from phenolic material, as mentioned above. Typically, the phenolic material will be molded at 340°C or higher and then _g_ cured at room temperature. During curing, cross-link shrinkage occurs to tighten and strengthen the material. Also, as the material reaches room temperature, it goes through thermal shrinkage.
In accordance with the principles of the present invention, however, the phenolic pulley structure I2 is brought down to approximately 200-220 °C after molding and is cured in an oven at this temperature for at least six hours to accomplish the aforementioned cross-link shrinkage.
After curing the pulley structure 12, it is removed from the oven.and placed in the lower die part 50 of the die assembly along with the ball bearing assembly 10 (which is at room temperature).
The molten material, preferably zinc, is then injected into the gap. After the zinc has cooled, the continued thermal shrinkage of the pulley structure 12 applies a further mechanical clamping l0 force in addition to that applied by the zinc as it cools. Therefore, both the zinc and the pulley structure I2 shrink down an the ball bearing assembly 10 to lock it in place.
Maintaining the pulley structure 12 at an elevated temperature and allowing it to shrink down on the Locking wedge 70 and ball bearing assembly 10 also provides the further advantage that the pulley structure 12 will still exert sufficient pressure on the wedge 70 to maintain a locked relation even during operation under high temperature conditions:
Referring more particularly to Fig: 8, there is shown therein an embodiment having modifications in addition to the constructions described above. Specifically, in place of the flared portions 74, 76, the locking element 70 has a set of outwardly and inwardly extending flanges 110, 112 on each side which engage flange engaging surfaces L 18; 120 formed on the faces of the pulley structure 12 and the ball bearing assembly 10. These flanges 110, I 12 are provided ( 1 ) to provide additional support against loosening of the pulley structure 12 and (2) to improve retention of the ball bearing assembly 10 in relation to the pulley structure I2. These flanges 1 I0, I 12 may be arranged so that their exposed surfaces have maximum radiation capabilities so as to dissipate heat during high temperature conditions.
Because zinc has excellent conductive capabilities, it is preferred for use in the locking wedge 70 over other materials for this additional reason. Furthermore, a plurality of fins-1 I4 are provided on the pulley structure 12 to increase air flow when the assembly 10 is in use, thereby dissipating a build-up of heat via convection. As can be seen by comparing Fig. 8 to Fig. 6, it is preferred that the shape of the locking wedge 70 shown in Fig. 6 is used in the embodiment of Fig. 8.
The pulley assembly of the present invention has several advantages. First, because a molten material is injected between the pulley structure 12 and ball bearing assembly 10 to form a mechanical interlocking connection, a relatively large gap between the pulley structure 12 and ball bearing assembly 10 can be used in comparison with a conventional arrangement where glue is used to adhere to the parts. Where glue or adhesive is used, a thinner or non-existent gap between parts must be used in order to obtain a su~ciently strong adhesive bond. More specifically, in conventional practice, a phenolic pulley may be molded, and while it is still in an expanded condition (before shrinkage) a ball bearing assembly may be inserted in the central aperture of the pulley. . Prior to shrinkage of the phenolic pulley, glue is inserted in the gap between the pulley and ball bearing assembly to make certain that the pulley is adequately secured to the ball bearing assembly.
Because a relatively larger gap can be used in accordance with the present invention, l0 there is less concern with the particular tolerances or dimensions of parts, as any gap between the ball bearing assembly and pulley structure will be completely filled.
Because there are less stringent dimension requirements, a relatively inexpensive pulley can be made of a molded phenolic material.
In addition, the solidified molten locking wedge provides a stronger mechanical bond in comparison with the conventional adhesive bond provided by glue. This is accomplished with a zinc/aluminum alloy, which is inexpensive, and which needs not undergo a curing process as with glue. Because curing is not required, manufacturing can be expedited, and the faults and difficulties associated with curing do not occur.
Because the preferred zinc/aluminum alloy has a relatively low specific heat;
it cools and solidifies almost instantly after being injected in the gap between the ball bearing assembly 10 and pulley structure I2. The instant cooling permits instant manual handling and also prevents heat degradation of the pulley assembly parts.
The present invention further contemplates that a pulley structure, similar to pulley structure 12, can be mounted directly on a shaft without the use of ball bearings. A molten material, such as those described above, can be injected between the shaft and pulley to provide a form-locking mechanical connection in a fashion similar to that noted above.
In addition, a ball bearing assembly may also be secured to the same shaft (or any shaft) in similar fashion to enable the shaft to be mounted for rotation.
It is to be understood that the foregoing description and accompanying drawings have ' been provided for illustrative purposes only; and that the present invention includes all modifications within the spirit and scope of the following claims.
PULLEY ASSEMBLY HAVING MOLDED CONNECTION
The present invention relates generally to a pulley assembly having an improved connection between a radially outer component and a radially inner component.
The invention relates more particularly to a pulley assembly having an improved molded connection between a pulley structure and a bearing assembly.
In particular the present invention provides a molded structural connection between the pulley and bearing that is simple to accomplish, improves the strength of the connection, is inexpensive to implement, and allows an inexpensive pulley structure component to be utilized.
Conventionally, glue or other similar adhesives have been used to connect a pulley structure to the outer race of a ball bearing assembly in a typical pulley assembly. When glue or other similar adhesives are used, there must be a thin or non-existent gap between the outer race of the ball bearing assembly and the pulley structure in order to obtain a sufficiently strong adhesive bond. In conventional practice, a phenolic pulley is molded and placed about the outer surface of the ball bearing assembly while in an expanded and heated state.
Glue is then inserted into the gap between the pulley structure and the ball bearing assembly. The pulley structure then shrinks as it cools to close the gap therebetween. Thus, as the pulley structure shrinks the glue adheres the surfaces of the ball bearing assembly and the pulley structure together.
However, in this conventional practice, there are stringent dimensional and tolerance requirements necessary to prevent (a) warpage of the ball bearing assembly caused by over-shrinkage of the phenolic pulley structure and (b) insufficient bonding of the phenolic pulley structure to the ball bearing assembly caused by a large gap formed by under-shrinkage of the pulley structure. Furthermore, even when these stringent dimensional and tolerance requirements are met it is still desirable to have a means of bonding the two components together which is stronger than the bonding afforded by glue or other similar adhesives.
Therefore, it is an object of the present invention to provide a process for manufacturing a pulley assembly which obviates the problems described above with the conventional practice of adhering components to one another. The process according to the present invention comprises the steps of providing an outer component of a pulley assembly having a central opening. The outer component has an inner surface surrounding the central opening. An inner component of the pulley assembly is provided having an outer surface.
The inner component is mounted within the central opening of the outer component. The _2_ _.
inner and outer component define a molten material receiving space therebetween. Molten material is then injected into the space. The molten material is cooled and forms a locking element. The locking element has radially extending portions providing axial movement limiting surfaces constructed and arranged to prevent axial movement of the outer component and the inner component relative to one another.
It is a further object of present invention to provide a pulley assembly comprising an outer component having a central opening. The outer component has an inner surface surrounding the central opening. An inner component has an outer wall and is disposed within the central opening of the outer component. A locking element has radially extending portions on opposing sides thereof providing axial movement limiting surfaces constructed and arranged to prevent axial movement of the outer and inner components relative to one another.
It is also a further object of the present invention to provide a pulley assembly comprising an outer component having a central opening. The central opening has an inner surface surrounding the central opening. An inner component has an outer wall. The inner component is disposed within the central opening of the outer component. A locking element is formed from solidified molten material and has radially extending portions providing axial movement limiting surfaces constructed and arranged to prevent axial movement of the inner and outer components relative to one another.
~1Z1FF DESORTPTION OF. THE DR.AWING~
2o Figure 1 is a cross sectional view of a ball bearing assembly prior to assembly in accordance with the principles of the present invention;
Figure lA is a cross sectional view of a pulley structure prior to assembly in accordance with the principles of the present invention; ' Figure 2 is a cross sectional view of the ball bearing assembly and pulley structure disposed in a lower die mold prior to an injection molded connection being provided to connect the ball bearing assembly with the pulley structure;
Figure 3 is a cross sectional view similar to the view shown in Figure 2, but further d showing an upper die mold disposed in a lowered position during an injection molding operation;
Figure 4 is a cross sectional view of a pulley assembly according to the principles of the present invention;
Figure 4A is a cross sectional view of the injection molded connection of Figure 4.
Figures 5-? are cross sectional views taken through the injection molded connection for connecting the ball bearing assembly to the pulley structure in,accordance with the'principles of the presentinvention.
Figure 8 is a cross sectional view similar to Figure 4 showing an alternative embodiment of a pulley assembly according to the principles of the present invention.
Figure 1 and lA are cross sectional views of an inner component in the form of a ball bearing assembly, generally indicated at 10, and an outer component in the form of a pulley structure, generally indicated at I2, prior to such components being connected to one another.
The ball bearing assembly 10 is conventional and includes an annular inner steel race 14, an annular outer steel race 16, and a plurality of steel ball elements 18 disposed therebetween.
The inner race 14 has an exterior surface comprising a substantially cylindrical surface portion and radially outwardly flared arcuate surface portions 22 and 24 extending from opposite ends of the cylindrical surface portion 20. Similarly, the outer race 16 has an exterior surface 15 comprising a main cylindrical surface portion 30, and arcuate surface portions 32 and 34 extending radially inwardly from opposite ends of the cylindrical wall portion 30. Each of the arcuate surface portions 22, 24, 32 and 34 are arcuate about a 1 mm radius, as is the case with most conventional ball bearings suited for the present application.
The pulley structure 12 has a generally annular construction. In particular, the pulley 20 structure 12 has a generally cylindrical peripheral wall portion 36 having a plurality of radially outwardly facing and circumferentially extending ribs 40 separated by a plurality of circumferendally extending grooves 42. The alternating ribs 40 and grooves 42 form what is known as a poly-V configuration constructed and arranged to engage associated ribs and grooves of a poly-V timing or accessory drive belt. The present invention is not limited to such type of pulley structures, but contemplates that the outer cylindrical wall portion 36 may have a smooth cylindrical outer surface constructed and arranged to engage the flat side of a timing or drive belt.
The pulley structure 12 further includes a radially extending wall portion 44 integrally formed with the cylindrical wall portion 36. The radially innermost portion of the wall portion 44, and hence of the pulley ~cture I2, constitutes an annular connecting portion 46 constructed and arranged to be connected with the radially outer periphery or outer race of the ball bearing assembly I0. It should be appreciated that while the wall portion 44 may take the _ q, _ _ form of a complete annular ring, it may'instead comprise a plurality of radially extending tab portions or spoke-like plates connecting the annular connecting portion 46 with the cylindrical wall portion 36.
The connecting portion 46 has a slightly greater thickness than the wall portion 44 and includes a radially innermost annular surface 48 of slightly greater diameter than the outer cylindrical surface portion 30 of the outer race 16.
It should be noted that the annular surface 48 has somewhat of a convex configuration. In the embodiment shown in Figures 1-S, this convex configuration is provided by a substantially cylindrical surface portion 45, and annular edges 47 and 49 (also referred to as inner edge to portions) which extend from opposite ends of the surface portion 45 at an obtuse angle of about 165 degrees with respect to the surface portion 45 as viewed in cross section:
In Figure 2, the pulley structure 12 and ball bearing assembly I O are shown mounted in a lower die part, generally indicated at 50. Together, the upper die part 60 and the lower die part 50 define a die assembly. The lower die part SO has a central interior pin 52 having an exterior diameter slightly smaller than the diameter of the inner cylindrical seuface portion 20The exterior configuration of pin 52 is constructed and arranged to form a close fit with the inner cylindrical surface portion 20 of the inner race 14: The lower die part 50 also includes a vertically extending cylindrical interior wall 54 having a diameter slightly greater than the outer diameter of the pulley structure 12. The cylindrical wall 54 is thus constructed and arranged to be disposed in close fitting engagement with peripheral portions of the cylindrical wall 36 of the pulley structure 12. The pin 52 and cylindrical wall 54 serve as locating elements for accurately positioning the pulley structure I2 relative to ball bearing assembly 10 in the lower die part 50 so as to maintain an annular gap or molten material receiving space 100 which provides relatively constant distance between the outer cylindrical wall portion 30 of the ball bearing assembly 10 and the inner annular surface 48 of the pulley structure 12.
Preferably, as will be described in greater detail later, this annular gap 100 is between .025 inches -.030 inches wide.
A~ can be appreciated from Figure 3, an upper metal die part 60 is lowered until it comes into forced engagement with the uppermost portion of the upwardly facing annular edge 47 (or 49 if inverted) of the pulley structure 12 and ball bearing assembly 10. As a result of this forced 3o engagement, a pair of downwardly facing radially spaced annular sealing surface portions of the upper die part 60 form radially spaced annular seals with the uppermost annular portion of the connecting portion 46 (or the uppermost portion of the upwardly facing annular edge 47 of such WO 98!34053 PCT/CA98l00063 connecting portion 46) and with the uppermost portion of the outer race's edge (or the uppermost portion of the upwardly facing arcuate surface portion 32 of such race's edge). The aforementioned forced engagement forces the ball bearing assembly 10 into forced engagement with the lower die part 50 in similar fashion. Particularly, radially spaced, upwardly facing annular sealing surface portions of the lower die part 50 form radially spaced annular seals with the lowermost portion of connecting portion (or the lowermost portion of the downwardly facing annular edge 49 of such connecting portion) and with a lowermost downwardly facing annular portion of the outer race {or the lowermost annular portion of the downwardly facing arcuate surface portion 34 of such race).
l0 The upper metal die part 60 has a plurality of circumferentially spaced pin holes 66 (also referred to as injecting holes) in the lower surface thereof between the downwardly facing radially spaced annular surface portions of the metal die,part forming the respective annular seals with the uppermost annular portion of the connecting portion {or of the upper annular surface 47 of the connecting portion) and the uppermost annular portion of the outer race 16 (or uppermost annular portion of arcuate surface portion 32 thereof). The pin holes 66 are positioned to inject an appropriate molten material into the sealed annular gap formed between the pulley structure 12 and ball bearing assembly Z 0.
Preferably, the molten material used is a zinc/aluminum alloy, such as ZA3 or ZAS alloy, or Accu-zinc. It is also possible to use substantially pure zinc, pure lead or glass-filled nylon.
The preferred molten zinc alloy beneficially has a low melting point and need only be heated to a temperature of between 825°-850° F.
Preferably, a pulley made from phenolic material is used, although steel, aluminum, zinc, or plastic pulleys are also possible. Phenolic is preferable because it is relatively inexpensive, and also because it absorbs heat at a relatively slow rate (i.e., in comparison with other possible materials), thus preventing the molten material from freezing or solidifying before it completely fills the sealed space or gap between the pulley structure 12 and ball bearing assembly 10.
Additional advantages of a phenolic pulley are noted later.
For a phenolic pulley, the gap 100 is preferably about .025 inches and no smaller than .020 inches wide to prevent freezing of the molten substance prior to the gap being completely filled. A smaller gap would accommodate a smaller amount of molten material;
which would in turn having a corresponding smaller thermal mass. In addition, the smaller the gap; the greater the percentage of molten material will be in contact with the surrounding metal surfaces. Thus, _ 6 . _. _ smaller gaps cause faster solidification of the molten material:
It should be noted that it is possible to prevent freezing from occurring with gaps of less than .02 inches by heating the pulley and ball bearing assembly during the injection molding process. However, this is not preferred, as heating of parts may cause some degradation thereof.
Where materials other than phenolic are used for the pulley structure 12 (e.g.
steel), a gap thicker than 0.25 inches is preferably used between the pulley structure 12 and ball bearing assembly 10 to prevent freezing. A still thicker gap must be used for an aluminum pulley. It should be noted, however, that irrespective of the pulley material, it is preferable to maintain a gap of less than .04 inches, because after the molten material solidifies, it tends to grab the ball bearing assembly by the outside diameter (as will be described in greater detail later) which may have a tendency to slightly deform the outer race 16. The greater the gap, the more force will be applied by the greater mass of solidified molten material, and the outer race 16 will be deformed to a greater extent as a result. Such deformation may have an undesirable effect on the ball bearing assembly 10.
Referring now to Figure 4, it can be appreciated that the sealed gap between the ball bearing assembly 10 and pulley structure 12, as well as the resultant solidified material therebetween, has a generally bow-tie cross-sectional configuration. In particular, the solidified material forms an annular locking wedge or element, generally indicated at 70, which has a cross sectional configuration that includes a cylindrical wall portion 72, and outwardly flared portions 74 and 76 or wedges at opposite ends thereof. The ball-bearing assembly side of the cylindrical wall portion 72 forms a cylindrical inner surface portion 78 which has a substantially similar configuration to the adjacent exterior surface 30 of the outer race 16 as a result of the injection-molding process: Similarly, the pulley side of the wall portion 72 forms a cylindrical outer surface portion 80 which is substantially similar in configuration to the adjacent cylindrical surface portion 45 of the pulley structure 12 as a result of the injection-molding process. The outwardly flared portions 74 and 76 of the annular locking wedge 70 are formed as a result of the convexly formed edges 47,49 of the connecting portion 46 of the pulley structure 12, and the convexly formed arcuate surface portions 32, 34 of the outer race 16.
The outwardly flared portion 74:includes a radially inwardly extending portion 75 and a radially outwardly extending portion 77. Similarly, the outwardly flared portion 76 includes a radially inwardly extending portion 79 and a radially outwardly extending portion 81.
It should be appreciated that inwardly extending portions 75, 79 have respective concave WO 98134053 ' PCT/CA98100063 surfaces portions (axial movement limiting surfaces} 82, 84 extending from opposite ends of the cylindrical surface portion 78 on the ball bearing side of the locking wedge 70. These arcuate surface portions 82, 84 have an arcuate configuration of an approximately 1 mm radius, matching the radius of the convex arcuate surface portions 32, 34 of the outer race 16. The radially outwardly extending portions 77 and 81 have respective angled surfaces (axial movement limiting surfaces) 86 and 88 which extend from opposite ends of cylindrical surface 80 at an angle with respect thereto. More particularly, the surface 80 has a generally straight cross-sectional configuration, and the opposite surface portions 86 and 88 extend at an angle of approximately 165° with respect to the straight surface 80. The configuration of surface 80 conforms substantially to the adjacent surface 45 of the connecting portion 46, while surfaces 86 and 88 respectively conform to edge portions 47 and 49 of the connecting portion 46.
It should be noted that as the injected molten material solidifies, it undergoes a slight shrinkage that assists in mechanically locking the pulley structure 12 to the ball bearing assembly l0. This will be described in greater detail with reference to Figures 5-7.
As shown in Figure 5, the locking wedge or element 70 shrinks in a longitudinal or axial direction by a distance D when comparing its configuration when cast at 750°F to its configuration at an operating temperature of 175°F. This longitudinal shrinkage causes the outwardly flared opposite longitudinal ends 74, 76 to apply a gripping force which mechanically grips the opposite edges of the outer race 16 and the opposite edges of the connecting portion 46, thus mechanically locking the pulley structure I2 to the ball bearing assembly 10. At the same time, a slight shrinkage of the cross-sectional width of the wall portion 72 by a distance X
which is substantially smaller than D, but nevertheless provides a slight clearance between the opposite surfaces 78 and 80 of the wall portion 72 and the respective adjacent surfaces 30 and 45 of the ball bearing assembly 10 and pulley structure I2. This slight clearance between the wall portion 72 and adjacent surfaces of the pulley structure 12 and ball bearing assembly 10 is advantageous in that less stress is applied by the locking wedge 70 o the central, more vulnerable portions of the outer race 16 and connecting portion 46.
It is also contemplated, though not preferable, that the locking wedge 70 will permit rotational movement of the pulley structure 12 and the ball bearing assembly I
O relative to one another. However, it is preferred that such relative rotational movement be prevented.
It is also contemplated that a plurality of grooves (not shown) may be provided on either the innermost annular surface 48 of the pulley structure 12 or main cylindrical surface portion WO 98J34053 PCTICA98t00063 _g_ 30 of the ball bearing assembly 10, or both. As such, one or more groove engaging portions {not shown) corresponding to the one or more gmoves will be formed on the locking wedge or element 70 as it is cooled. These groove engaging portions engage the corresponding one or more grooves to prevent axial movement between the ball bearing assembly 10 and the pulley structure 12.
As noted above, the annular surface 48 of the pulley structure 12 preferably has a convex configuration which forms a corresponding concave configuration on the adjacent portions of locking wedge 70. In particular, surface portions 86, 80, and 88 of the locking wedge 70 together form a concave surface. It is preferred that the surface portions 86 and 88 form an obtuse angle of approximately 165 ° with respect to surface 80 and have a length of about 3 mm.
In another embodiment, the inner convex surface of the pulley is formed by two annular surfaces which are angled with respect to one another and meet at a mutual boundary point. As a result, as shown in Figure 6; an annular locking wedge 90 will be formed having a concave surface 94 comprising a pair of angled surface portions 96 snd 98 as shown. The configuration shown in Figure 6 causes a more uniform load to be applied to the pulley after shrinking of the wedge.
Figure 7 is a variation of the embodiment shown in Figure 6. Figure 7 shows an annular locking wedge 98 having an arcuate surface 104 adjacent the pulley which has a substantially smoothly formed concave configuration. As with the previous embodiments, the surface i04 is constructed and arranged to be disposed in locking geometric relation with a correspondingly 2o formed, smooth convex configuration of the inner annular surface of the associated pulley structure. In this configuration, the load on the pulley is greatest at the peripheral portions of the surface 104 and is zero at the center.
It should be appreciated that the surfaces 80, 94; and 104 of the respective embodiments of Figures 5, 6, and 7 each take a configuration which is substantially dictated by the particular configuration of the inner annular surface (e.g. annular surface 48 'of the first embodiment) of the pulley structure 12. Thus, the load on the pulley structure 12 can be modified in accordance with the particular configuration of the inner annular surface of the pulley structure 12:
It should also be appreciated that the opposite concave surface of the locking wedges 70, 90, and 98 have substantially the same configuration as one another and is dictated by the same 3o conventional ball bearing assembly used with each.
It is preferable that the pulley structure 12 be molded from phenolic material, as mentioned above. Typically, the phenolic material will be molded at 340°C or higher and then _g_ cured at room temperature. During curing, cross-link shrinkage occurs to tighten and strengthen the material. Also, as the material reaches room temperature, it goes through thermal shrinkage.
In accordance with the principles of the present invention, however, the phenolic pulley structure I2 is brought down to approximately 200-220 °C after molding and is cured in an oven at this temperature for at least six hours to accomplish the aforementioned cross-link shrinkage.
After curing the pulley structure 12, it is removed from the oven.and placed in the lower die part 50 of the die assembly along with the ball bearing assembly 10 (which is at room temperature).
The molten material, preferably zinc, is then injected into the gap. After the zinc has cooled, the continued thermal shrinkage of the pulley structure 12 applies a further mechanical clamping l0 force in addition to that applied by the zinc as it cools. Therefore, both the zinc and the pulley structure I2 shrink down an the ball bearing assembly 10 to lock it in place.
Maintaining the pulley structure 12 at an elevated temperature and allowing it to shrink down on the Locking wedge 70 and ball bearing assembly 10 also provides the further advantage that the pulley structure 12 will still exert sufficient pressure on the wedge 70 to maintain a locked relation even during operation under high temperature conditions:
Referring more particularly to Fig: 8, there is shown therein an embodiment having modifications in addition to the constructions described above. Specifically, in place of the flared portions 74, 76, the locking element 70 has a set of outwardly and inwardly extending flanges 110, 112 on each side which engage flange engaging surfaces L 18; 120 formed on the faces of the pulley structure 12 and the ball bearing assembly 10. These flanges 110, I 12 are provided ( 1 ) to provide additional support against loosening of the pulley structure 12 and (2) to improve retention of the ball bearing assembly 10 in relation to the pulley structure I2. These flanges 1 I0, I 12 may be arranged so that their exposed surfaces have maximum radiation capabilities so as to dissipate heat during high temperature conditions.
Because zinc has excellent conductive capabilities, it is preferred for use in the locking wedge 70 over other materials for this additional reason. Furthermore, a plurality of fins-1 I4 are provided on the pulley structure 12 to increase air flow when the assembly 10 is in use, thereby dissipating a build-up of heat via convection. As can be seen by comparing Fig. 8 to Fig. 6, it is preferred that the shape of the locking wedge 70 shown in Fig. 6 is used in the embodiment of Fig. 8.
The pulley assembly of the present invention has several advantages. First, because a molten material is injected between the pulley structure 12 and ball bearing assembly 10 to form a mechanical interlocking connection, a relatively large gap between the pulley structure 12 and ball bearing assembly 10 can be used in comparison with a conventional arrangement where glue is used to adhere to the parts. Where glue or adhesive is used, a thinner or non-existent gap between parts must be used in order to obtain a su~ciently strong adhesive bond. More specifically, in conventional practice, a phenolic pulley may be molded, and while it is still in an expanded condition (before shrinkage) a ball bearing assembly may be inserted in the central aperture of the pulley. . Prior to shrinkage of the phenolic pulley, glue is inserted in the gap between the pulley and ball bearing assembly to make certain that the pulley is adequately secured to the ball bearing assembly.
Because a relatively larger gap can be used in accordance with the present invention, l0 there is less concern with the particular tolerances or dimensions of parts, as any gap between the ball bearing assembly and pulley structure will be completely filled.
Because there are less stringent dimension requirements, a relatively inexpensive pulley can be made of a molded phenolic material.
In addition, the solidified molten locking wedge provides a stronger mechanical bond in comparison with the conventional adhesive bond provided by glue. This is accomplished with a zinc/aluminum alloy, which is inexpensive, and which needs not undergo a curing process as with glue. Because curing is not required, manufacturing can be expedited, and the faults and difficulties associated with curing do not occur.
Because the preferred zinc/aluminum alloy has a relatively low specific heat;
it cools and solidifies almost instantly after being injected in the gap between the ball bearing assembly 10 and pulley structure I2. The instant cooling permits instant manual handling and also prevents heat degradation of the pulley assembly parts.
The present invention further contemplates that a pulley structure, similar to pulley structure 12, can be mounted directly on a shaft without the use of ball bearings. A molten material, such as those described above, can be injected between the shaft and pulley to provide a form-locking mechanical connection in a fashion similar to that noted above.
In addition, a ball bearing assembly may also be secured to the same shaft (or any shaft) in similar fashion to enable the shaft to be mounted for rotation.
It is to be understood that the foregoing description and accompanying drawings have ' been provided for illustrative purposes only; and that the present invention includes all modifications within the spirit and scope of the following claims.
Claims (31)
1. A process for manufacturing a pulley assembly comprising the steps of providing a radially outer component of said pulley assembly, said outer component having a central opening and an annular, radially inner surface surrounding said opening;
providing a radially inner component of said pulley assembly, said inner component having an annular, radially outer wall;
disposing said inner component within said central opening of said outer component, said inner component and said outer component defining molten material receiving space therebetween;
injecting molten material into said space;
solidifying said molten material to form a rigid annular locking element, said locking element having radially extending portions on opposite axial sides thereof providing rigid structure defining axial movement limiting surfaces, said axial movement limiting surfaces being formed by at least one of said annular, radially inner surface and said annular, radially outer wall having one or more grooves formed thereon and one or more groove engaging projections corresponding to said one or more grooves formed on said locking element as a result of the solidification thereof, said groove engaging projections engaging said one or more grooves preventing axial movement of said inner component and said outer component relative to one another.
providing a radially inner component of said pulley assembly, said inner component having an annular, radially outer wall;
disposing said inner component within said central opening of said outer component, said inner component and said outer component defining molten material receiving space therebetween;
injecting molten material into said space;
solidifying said molten material to form a rigid annular locking element, said locking element having radially extending portions on opposite axial sides thereof providing rigid structure defining axial movement limiting surfaces, said axial movement limiting surfaces being formed by at least one of said annular, radially inner surface and said annular, radially outer wall having one or more grooves formed thereon and one or more groove engaging projections corresponding to said one or more grooves formed on said locking element as a result of the solidification thereof, said groove engaging projections engaging said one or more grooves preventing axial movement of said inner component and said outer component relative to one another.
2. The process according to claim 1, further comprising:
said outer component being disposed above room temperature in an expanded configuration prior to said disposing, and after said disposing, cooling said outer component, said outer component shrinking as a result of said cooling to apply an inwardly, radially directed force to said locking element.
said outer component being disposed above room temperature in an expanded configuration prior to said disposing, and after said disposing, cooling said outer component, said outer component shrinking as a result of said cooling to apply an inwardly, radially directed force to said locking element.
3. The process according to claim 2, further comprising:
molding said outer component from a molten phenolic resin material;
maintaining said outer component at a temperature range low enough and for a sufficient period of time to permit said phenolic resin material to cure, said temperature range being high enough to provide the outer component with said expanded configuration prior to said disposing said inner component within said central opening.
molding said outer component from a molten phenolic resin material;
maintaining said outer component at a temperature range low enough and for a sufficient period of time to permit said phenolic resin material to cure, said temperature range being high enough to provide the outer component with said expanded configuration prior to said disposing said inner component within said central opening.
4. The process according to claim 3 wherein said inner component is a ball bearing assembly and said outer component is a pulley structure.
5. The process according to claim 3 wherein said inner component is a shaft and said outer component is a ball bearing assembly.
6. The process according to claim 3 wherein said inner component is a shaft and said outer component is a pulley structure.
7. A process according to claim 3 wherein said molten material is a zinc/aluminum alloy.
8. A process according to claim 3 wherein said molten material is substantially pure zinc.
9. A process according to claim 3 wherein said molten material is glass-filled nylon.
10. A process according to claim 3, wherein the inwardly, radially directed force is transmitted through said locking element to said inner component to secure said inner component, said locking element, and said outer component to one another.
11. A process according to claim 2 wherein said temperature range is between 200°C-220°C.
12. A process according to claim 11 wherein said sufficient period of time is approximately 6 hours.
13. A process according to claim 1 wherein said annular, radially inner surface has an arcuate convex shape.
14. A process according to claim 1 wherein said annular, radially inner surface has a convex shape defined by two surfaces angled with respect to one another along a line of intersection.
15. A process according to claim 1 wherein said locking element shrinks in an axially inward direction as a result of the solidifying such that said axial movement limiting surfaces each apply an axially inward gripping force directed towards one another to said inner component and said outer component to prevent axial movement of said inner component and said outer component relative to one another.
16. A process according to claim 1 wherein said molten material receiving space is a gap extending circumferentially between said annular, radially inner surface and said annular, radially outer wall, said inner surface being spaced from said outer wall at a predetermined distance.
17. A process according to claim 16 wherein said predetermined distance is .025-.030 inches.
18. A pulley assembly comprising:
an outer component having a central opening, said outer component having an annular, radially inner surface surrounding said central opening;
an inner component having a annular, radially outer wall, said inner component being disposed within said central opening of said outer component;
a locking element having radially extending portions on opposite sides thereof providing rigid structure defining axial movement limiting surfaces, said axial movement limiting surfaces comprising one or more grooves formed on at least one of said annular, radially inner surface and said annular, radially outer wall; and one or more groove engaging projections corresponding to said one or more grooves extending from said locking element and engaging said one or more grooves, preventing axial movement of said inner component and said outer component relative to one another.
an outer component having a central opening, said outer component having an annular, radially inner surface surrounding said central opening;
an inner component having a annular, radially outer wall, said inner component being disposed within said central opening of said outer component;
a locking element having radially extending portions on opposite sides thereof providing rigid structure defining axial movement limiting surfaces, said axial movement limiting surfaces comprising one or more grooves formed on at least one of said annular, radially inner surface and said annular, radially outer wall; and one or more groove engaging projections corresponding to said one or more grooves extending from said locking element and engaging said one or more grooves, preventing axial movement of said inner component and said outer component relative to one another.
19. A pulley assembly according to claim 18 further comprising flange engaging surfaces extending radially along opposing faces of said outer component and said inner component;
said radially extending portions of said locking element being radially extending flanges engaging said flange engaging surfaces.
said radially extending portions of said locking element being radially extending flanges engaging said flange engaging surfaces.
20. A pulley assembly according to claim 18 wherein said outer component is a pulley structure and said inner component is a ball bearing assembly.
21. A pulley assembly according to claim 18 wherein said outer component is a pulley structure and said inner component is a shaft.
22. A pulley assembly according to claim 18 wherein said outer component is a ball bearing assembly and said inner component is a shaft.
23. A pulley assembly according to claim 18 wherein said annular, radially inner surface has an arcuate convex shape.
24. A pulley assembly according to claim 18 wherein said annular, radially inner surface has a convex shape defined by two surfaces angled with respect to one another along a line of intersection.
25. A pulley assembly according to claim 18 wherein said locking element is made of a zinc/aluminum alloy.
26. A pulley assembly according to claim 18 wherein said locking element is made of substantially pure zinc.
27. A pulley assembly according to claim 18 wherein said locking element is made of glass-filled nylon.
28. A pulley assembly according to claim 18 wherein said outer component is made of phenolic material.
29. A pulley assembly according to claim 18 wherein said outer component is made of a cellulose material.
30. A pulley assembly according to claim 18 wherein said locking element is constructed and arranged to prevent rotational movement of said outer component and said inner component relative to one another.
31. A pulley assembly according to claim 18 wherein said outer component is a pulley structure and said inner component is a ball bearing assembly, said pulley structure having one or more fin structures constructed and arranged to provide airflow to said pulley assembly as said pulley structure rotates, thereby dissipating heat from said pulley assembly via convection.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US3727997P | 1997-02-03 | 1997-02-03 | |
| US60/037,279 | 1997-02-03 | ||
| PCT/CA1998/000063 WO1998034053A1 (en) | 1997-02-03 | 1998-02-03 | Pulley assembley having molded connection |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2279896A1 CA2279896A1 (en) | 1998-08-06 |
| CA2279896C true CA2279896C (en) | 2007-03-20 |
Family
ID=21893477
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002279896A Expired - Lifetime CA2279896C (en) | 1997-02-03 | 1998-02-03 | Pulley assembly having molded connection |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU5850198A (en) |
| CA (1) | CA2279896C (en) |
| WO (1) | WO1998034053A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2790801B1 (en) | 1999-03-08 | 2001-04-13 | Skf France | ROLLING BEARING WITH SEALS AND METHOD OF FIXING SEALS ON A BEARING |
| FR2791289B1 (en) | 1999-03-26 | 2001-05-04 | Skf France | PROCESS FOR MANUFACTURING A ROLLER ROLLER |
| DE102004021349B4 (en) * | 2004-04-30 | 2009-11-05 | Ab Skf | Method for producing a bearing arrangement |
| DE102004021348B4 (en) * | 2004-04-30 | 2009-06-18 | Ab Skf | Method for fixing a bearing |
| US20070232427A1 (en) | 2006-03-29 | 2007-10-04 | Jtekt Corporation | Pulley assembly and pulley usable therefor |
| WO2010105644A1 (en) * | 2009-03-19 | 2010-09-23 | Ab Skf | Method of manufacturing a bearing ring |
| CN107687512B (en) * | 2016-08-05 | 2021-02-05 | 株式会社日立制作所 | Pulley wheel |
| DE102019201752A1 (en) * | 2019-02-11 | 2020-08-13 | Aktiebolaget Skf | Pulley device especially for a tension pulley or a pulley |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4111623A (en) * | 1976-09-16 | 1978-09-05 | Pemco-Kalamazoo, Inc. | Apparatus for assembling bearing unit in a wheel |
| US4366609A (en) * | 1979-09-17 | 1983-01-04 | Dayco Corporation | Composite pulley and method for making |
| US4535827A (en) * | 1984-03-07 | 1985-08-20 | Wil-Mat Corporation | Molded shock-absorbing wheel assembly |
| JP2610932B2 (en) * | 1988-03-08 | 1997-05-14 | 光洋精工株式会社 | Rotor made of resin with bearing |
| US4913688A (en) * | 1989-06-12 | 1990-04-03 | Ford Motor Company | Pulley assembly for accessory clutch having nonmetallic sheave |
| SE503025C2 (en) * | 1994-07-25 | 1996-03-11 | Industriverktyg Ab | A method of fixing a bearing in a wheel hub and wheels made by the method |
-
1998
- 1998-02-03 CA CA002279896A patent/CA2279896C/en not_active Expired - Lifetime
- 1998-02-03 AU AU58501/98A patent/AU5850198A/en not_active Abandoned
- 1998-02-03 WO PCT/CA1998/000063 patent/WO1998034053A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO1998034053A1 (en) | 1998-08-06 |
| AU5850198A (en) | 1998-08-25 |
| CA2279896A1 (en) | 1998-08-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2279896C (en) | Pulley assembly having molded connection | |
| US10864963B2 (en) | Bicycle crank arm and insert therefore | |
| US7594568B2 (en) | Rotor assembly and method | |
| US7861832B2 (en) | Thermally accommodating interconnection for cast-in-place components | |
| KR910004976B1 (en) | Spherical bearing and its manufacturing method | |
| US6059095A (en) | Conveying roller and a method for producing the same | |
| US8701854B2 (en) | Friction plates and various methods of manufacture thereof | |
| US4187135A (en) | Fiber reinforced composite shaft with metallic connector sleeves mounted by longitudinal groove interlock | |
| JPH1094203A (en) | Motor rotor and manufacture thereof | |
| EP0321582A1 (en) | Method of molding motor stator | |
| JPS60223448A (en) | Rotary electric machine | |
| JPH0518412A (en) | Spherical surface slide bearing and its manufacture | |
| US20110290602A1 (en) | Interconnection for cast-in-place components | |
| US5094076A (en) | Torque converter reactor assembly and method | |
| JPH07224946A (en) | Sealing device | |
| KR100217550B1 (en) | Superconducting coil and manufacturing method thereof | |
| JP2844877B2 (en) | Rotating head cylinder and method of manufacturing the same | |
| JP3065045B2 (en) | Semiconductor device | |
| US4935085A (en) | Process for producing urethane die | |
| US5078588A (en) | Stringiness-preventing pad used in an injection mold | |
| JPS6140983Y2 (en) | ||
| WO2022014930A1 (en) | Floating disc hub assembly for vehicle | |
| JP4461717B2 (en) | Electric motor and electric motor manufacturing method | |
| JPS62216711A (en) | Method of joining ceramics and metal | |
| JPH11277571A (en) | Monolithic molding method for reinforcing bonding strength between resin member and metallic member |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20180205 |