JP2000055058A - High temperature polymer thrust bearing cage and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage of a pocket part in removing a pocket forming tool by arranging three pairs of roller holding tubs on each pocket and distantly arranging one pair of tubs of the three pairs of tubs on one surface of an annular body and other two pairs of tubs on the other surface. SOLUTION: A roller cage 50 is constituted of an annular cage main body 60 provided with a plurality of long and narrow pockets 70 arrayed in a radial direction. In this case, a roller is held by holding tubs 75, 80 arranged alternately on upper and lower surfaces of the cage main body 60. The alternate holding tubs 75, 80 on side walls of the pockets 70 which are straight in a direction parallel to an axis of this cage main body 60 and the upper and lower surfaces of the cage main body 60 can be pulled without applying deformation force to the tubs 75, 80 at all by being pulled in the vertical bi-directions by using two opposed core pin members to be used in forming a roller pocket 70 and the tubs 75, 80. As a result, destruction of a holding constitution while removing the cage 50 from the forming tool and a metallic mold can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates generally to roller thrust bearings and, more particularly, to roller cages and methods of making such cages from high temperature polymeric materials.

[0002]

2. Description of the Prior Art The requirement for roller thrust bearings that can operate faster for a longer period of time with less oil flow is the requirement for bearing temperature, the use of polymers commonly used to make roller cages. It has grown to such an extent that the requirements cannot be met. Some recent specially designed polymers can withstand the high operating temperatures encountered in such uses, but it is difficult or impossible to mold cages using those polymers into existing molds. is there. The softer and more resilient polymer used in commonly used thrust bearings will allow removal of forming tools through the narrowed hole between the pocket retention features, but the hot polymer is Because of the much stiffer and more brittle nature, the roller pocket retention arrangement is often completely damaged or broken during removal of existing mold pocket forming tools.

[0003]

The foregoing illustrates the limitations known in current designs of cages for roller thrust bearings. Accordingly, it would be advantageous to provide an alternative aimed at overcoming one or more of the limitations set forth above. It is therefore an issue to provide suitable alternatives with the features that will be more fully disclosed later.

[0004]

SUMMARY OF THE INVENTION In one aspect of the invention, this comprises a flat annular body having a circular inner bore about an axis and side walls each straight in a direction parallel to the axis of the annular body. A plurality of hollow radially oriented roller pockets having an elongated cavity, and at least three pairs of roller retaining tabs located in each pocket, at least one pair of the tabs being one of the annular bodies. And at least two pairs of the tabs are radially spaced apart from each other on the other side of the annulus and radially offset from at least one pair on the one side of the annulus. This is achieved by a high temperature resistant polymer roller cage for roller thrust bearings.

[0005] The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As used throughout this description, the terms radial, axial, upper and lower refer to FIG.
8 to the radius and axis of the flat annular thrust bearing retainer. The prior art has many different designs of roller cages for roller thrust bearings. One such design is shown schematically in FIGS. 1-4 wherein the roller retainer 15 has a flat annulus 20 with a plurality of elongated radially directed pockets 25. In each of the plurality of pockets 25, the rollers are held. The width of the pocket 25 on the upper and lower surfaces of the retainer body 20 is
Smaller than the diameter of Thus, while the rollers 30 are loosely seated in the pockets 25 of the retainer 20, it is necessary to push the rollers into the pockets, which may be difficult if the forces must not damage the edges of the retainer pockets. Requires some elasticity to the vessel edge.

The pocket forming tools (half by half) 35 a, 35 b shown in FIG. 4 have a diameter or maximum dimension larger than the diameter of the rollers 30. These tools are used as a core around which a polymer is injected into a mold and roller pockets are formed in a retainer. The pockets 25a, 25b and the tools 35a, 35b forming them can have virtually any shape of circular or polygonal cross-section as long as the rollers cannot be loosely fitted and fall off. Once the polymer has been molded and cured around the tool, the tool must be removed in the direction of the arrow. While this removal method is possible with the prior art soft polymers, it is very difficult, if not impossible, to use high temperature polymers as currently required for more demanding applications. This results in excessive losses during fabrication due to breaking of the holding arrangement during removal of the cage from the forming tool and mold.

FIGS. 5-8 schematically illustrate a roller retainer 50 made by the method of the present invention. It consists of an annular retainer body 60 with a plurality of radially arranged elongated pockets 70. In this case, roller 3
0 is retained by retaining tabs 75 and 80 alternately arranged on the upper and lower surfaces of the retainer body 60. Figures 7 and 8
Is the retainer body 60 at lines 7-7 and 8-8 in FIG.
2 shows a side view of the pocket 70 with straight walls. These straight side walls, which are straight in a direction parallel to the axis of the retainer body 60, and alternating retaining tabs 75, 80 on the upper and lower surfaces of the retainer body are used when forming the roller pockets 70 and tabs. The bidirectional axial withdrawal of the opposing core pin is possible without applying any deforming force to the tab. This configuration, shown in conjunction with FIGS. 9 and 10, shows the roller pockets 70 and the core pin members 90 and 1 of a single core pin pair used to form them.
00 shows a functional design. The core pin 90 comprises a ridge formed by a specially profiled axial projection 77 radially flanked by two flat axially recessed portions 79. Core pin 100
Are two specially contoured axially projecting portions 95 that limit the radial sides of the flat axially recessed portion 85
Consists of Note that the core pin members 90, 100 are shown with very thick flat axially concave portions 79,85. This is exaggerated to show and illustrate the shape of the complementary core pin member used to form the pocket 70 of the present invention. By this means, the core pin members can be described as bumps having portions that protrude or dent alternately.

An alternative embodiment of a core pin pair 190, 200 is shown in FIGS.
When interdigitated into the mold cavity, the core pin pair creates a mold cavity having a cross section as shown in FIGS. Side walls and retention tabs 180, 175
The rounded profile between the two reduces the cutout effect created by the crossed flat surfaces and allows for greater resistance to mechanical damage. However, such rounded contour pins are more difficult to manufacture than those with crossed flat surfaces, which increases the manufacturing cost.

In any of the embodiments, it may be desirable to reduce the radial size of the retaining tabs in order to increase the ease of mounting the rollers in the pocket. This is accomplished by providing a core pin of the type shown in FIGS. 15 and 16, in which the profiled axial projections 277, 295 of the core pins 290 and 300 are shown.
Are engaged with the flat axially recessed portions 285, 279, respectively, when the mold is closed.

In its simplest form, the core pins are fixed directly to the upper and lower covers of the mold and are inserted or removed axially from the mold cavity along the upper and lower covers. Note that the top and bottom are actually right and left depending on the design of the molding equipment. The parallel sides of the core pin member allow the pin to be easily withdrawn from the molded retainer and vice versa. In a more complicated and expensive mold, the core pin member can reciprocate in the axial direction through the upper and lower mold covers due to the parallel side surfaces of the protrusions,
An intermeshing position in the mold cavity can be reached, thereby defining a roller cavity in the forming roller cage.

Depending on the polymer molding material chosen, certain curing equipment may be included in the method of the present invention. this is,
This may include heating or cooling the mold while keeping the formed retainer in the mold.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a conventional thrust bearing roller cage made with current mold design.

FIG. 2 is a partial cross-sectional elevation view of a roller pocket of the conventional roller cage, as viewed in the direction of the arrow along line 2-2 in FIG.

FIG. 3 is a partial sectional perspective view of FIGS. 1 and 2;

FIG. 4 is an elevational view of two prior art common pocket forming tools and the pockets formed thereby, each half being shown.

FIG. 5 is a plan view of a roller cage made according to the method of the present invention.

FIG. 6 is a partial cross-sectional perspective view of one of the roller pockets of FIG. 5 with rollers added.

FIG. 7 to show preferred roller pocket shapes;
FIG. 7 is a cross-sectional elevation view as seen in the direction of the arrow attached to line 7-7 of FIG.

FIG. 8 is a view similar to FIG. 7, taken along line 8-8 of FIG. 5;

FIG. 9 is a schematic view of one member of a Copian pair of the present invention used in the configuration shown in FIG.

FIG. 10 is used to create the shape in FIG. 7 and FIG.
FIG. 4 is a view of a member opposed to a core pin in FIG.

FIG. 11 shows one member of another embodiment of two complementary core pin members.

FIG. 12 is a sectional view of a cage pocket member made of the core pin member of FIG. 11;

FIG. 13 is a schematic perspective view of a complementary core pin member of the core pin member of FIG. 11;

FIG. 14 is a cross-sectional view of a retainer pocket created by the core pin member of FIG.

FIG. 15 illustrates one member of a core pin pair used to form a retainer having a retaining tab having a reduced radial length.

16 is a view showing a complementary core pin member of the core pin member of FIG.

[Explanation of symbols]

30 Roller 50 Cage 60 Annular body 70 Pocket 75, 80, 175, 180, 275, 280 Tab 77, 95, 177, 195, 277, 295 Projecting portion 79, 85, 179, 185, 279, 285 Depressed portion 90 , 100, 190, 200, 290, 300 Core pin member

Claims (6)

[Claims] 1. A high temperature resistant polymer roller cage for a roller thrust bearing, comprising: a flat annular body having a circular inner hole around an axis; and a plurality of hollow radially oriented roller pockets, wherein the roller pockets An elongate cavity having straight sidewalls in a direction parallel to the axis of the annulus; and at least three pairs of roller retaining tabs located in each pocket, at least one of the tabs being one surface of the annulus. Wherein at least two pairs of said tabs are on opposite sides of said annular body and are radially offset from said at least one pair on said one side of said annular body. 2. A method for making a roller cage for a roller thrust bearing from a high temperature polymer, comprising: a mold having at least one flat annular cavity and a suitable injection gate and riser, wherein the cavity is formed by a mold body and upper and lower cover members. Providing a formed mold and providing a plurality of pairs of radially arranged core pins in each flat annular cavity, wherein the core pin members are complementary to the core pin members in the lower cover and the upper cover. An opposing core pin member is provided, wherein each core pin member comprises an elongated ridge having alternating specially contoured axial projections and flat axially recessed portions, wherein the core pin member is configured such that the core pin member extends in the axial direction. When the mold is closed by extending into the flat annular cavity and interlocking with each other, the protrusion of the special contour shape of one member of the core pin pair is flat. The concave portion contacts the complementary flat concave portion and the specially contoured protruding portion of the other member of the core pin pair, and the cover member is pressed against the mold body and tightened in the axial direction. Closing the mold by injecting a high-temperature polymer material into a cavity in the mold to cure the high-temperature polymer material; removing the upper and lower covers and removing in an axial direction; A roller thrust bearing for roller thrust bearings from a high-temperature polymer, comprising the steps of: 3. The method of claim 2, wherein said mold body includes a lower cover member secured thereto. 4. The core pin member on the upper cover member has a single special contoured projection between two flat recessed portions, and the core pin member on the lower cover member has two special contour shapes. 3. A method according to claim 2, comprising a single flat recess between the protruding portions of the second. 5. A method of making a hot polymer roller cage for a roller thrust bearing, comprising: a mold having one or more flat annular cavities and a suitable injection gate and riser, said cavities comprising a mold body and at least an upper cover. Providing a mold formed by a member; and reciprocating in a plurality of radially arranged axial directions within a surface disposed opposite the upper cover member and the mold body for each annular annular cavity. Providing a movable core pin pair, wherein the core pin pair comprises complementary opposing core pin members, each core pin member consisting of alternating specially shaped protrusions and flat recessed portions, wherein the core pin member comprises: Reciprocally axially reciprocally in opposite directions for intermeshing within a flat annular cavity, and having a specially contoured protruding portion of one member of the core pin pair. The concave portions are adapted to contact complementary flat concave portions and specially shaped protrusion portions of the other member of the core pin pair, respectively, so that the core pin member is connected to the one or more flat members. Reciprocating to an intermeshing position in the annular cavity;
Injecting a high-temperature polymer material into the mold and curing the high-temperature polymer material as required; reciprocating the core pin members from an intermeshing position; opening the mold and holding the polymer roller Ejecting the cage from the high temperature polymer. 6. A mold body comprising an injection gate and a riser, upper and lower covers, and one or more flat annular cavities; and a plurality of radially arranged pairs of core pins in each flat annular cavity. The member comprises a core pin member on the lower cover and a complementary opposing core pin member on the upper cover, each core pin member having an elongated ridge with alternating axially protruding portions and flat axially concave portions of a special contour. The core pin member has a specially contoured protruding portion and a flat recessed portion of one member of the core pin pair, and when attaching the upper and lower cover members to the mold body, the other of the core pin pair. The core pin member extends axially into the flat annular cavity so as to contact the complementary flat recessed portion and the specially contoured protruding portion of the member, respectively. A means for closing the mold by fastening the cover member to the mold body, a step of curing the high-temperature polymer material as necessary, and a means for discharging the polymer roller retainer from the mold. High temperature polymer roller cage working mold for roller thrust bearings.