US20220388209A1 - Bearing cage and manufacturing method therefor - Google Patents
Bearing cage and manufacturing method therefor Download PDFInfo
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- US20220388209A1 US20220388209A1 US17/890,838 US202217890838A US2022388209A1 US 20220388209 A1 US20220388209 A1 US 20220388209A1 US 202217890838 A US202217890838 A US 202217890838A US 2022388209 A1 US2022388209 A1 US 2022388209A1
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- Prior art keywords
- resin
- weld line
- pillar
- pillar part
- bearing cage
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- 238000004519 manufacturing process Methods 0.000 title description 48
- 238000005520 cutting process Methods 0.000 claims description 28
- 229920005989 resin Polymers 0.000 abstract description 248
- 239000011347 resin Substances 0.000 abstract description 248
- 238000002347 injection Methods 0.000 abstract description 35
- 239000007924 injection Substances 0.000 abstract description 35
- 239000000463 material Substances 0.000 description 32
- 239000012783 reinforcing fiber Substances 0.000 description 29
- 230000000694 effects Effects 0.000 description 21
- 230000002093 peripheral effect Effects 0.000 description 21
- 230000000052 comparative effect Effects 0.000 description 8
- 238000005096 rolling process Methods 0.000 description 8
- 238000001746 injection moulding Methods 0.000 description 5
- 239000004677 Nylon Substances 0.000 description 4
- 239000004696 Poly ether ether ketone Substances 0.000 description 4
- 239000004734 Polyphenylene sulfide Substances 0.000 description 4
- 230000003247 decreasing effect Effects 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 229920001778 nylon Polymers 0.000 description 4
- 229920002530 polyetherether ketone Polymers 0.000 description 4
- 229920000069 polyphenylene sulfide Polymers 0.000 description 4
- 230000003014 reinforcing effect Effects 0.000 description 4
- 229920000049 Carbon (fiber) Polymers 0.000 description 3
- 239000004917 carbon fiber Substances 0.000 description 3
- 239000003365 glass fiber Substances 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- 239000011342 resin composition Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- -1 polybutylene terephthalate Polymers 0.000 description 2
- 229920001707 polybutylene terephthalate Polymers 0.000 description 2
- 229920003002 synthetic resin Polymers 0.000 description 2
- 239000000057 synthetic resin Substances 0.000 description 2
- 241000946381 Timon Species 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000012779 reinforcing material Substances 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
Images
Classifications
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- 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
- B29C45/0025—Preventing defects on the moulded article, e.g. weld lines, shrinkage marks
-
- 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
- B29C45/0046—Details relating to the filling pattern or flow paths or flow characteristics of moulding material in the mould cavity
-
- 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
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/2616—Moulds having annular mould cavities
-
- 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
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/2669—Moulds with means for removing excess material, e.g. with overflow cavities
-
- 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
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/27—Sprue channels ; Runner channels or runner nozzles
- B29C45/2701—Details not specific to hot or cold runner channels
- B29C45/2708—Gates
-
- 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
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/30—Parts of ball or roller bearings
- F16C33/38—Ball cages
- F16C33/41—Ball cages comb-shaped
- F16C33/412—Massive or moulded comb cages, e.g. snap ball cages
- F16C33/414—Massive or moulded comb cages, e.g. snap ball cages formed as one-piece cages, i.e. monoblock comb cages
- F16C33/416—Massive or moulded comb cages, e.g. snap ball cages formed as one-piece cages, i.e. monoblock comb cages made from plastic, e.g. injection moulded comb cages
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
- B29K2105/12—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of short lengths, e.g. chopped filaments, staple fibres or bristles
-
- 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
- B29L2031/04—Bearings
-
- 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
- B29L2031/04—Bearings
- B29L2031/045—Bushes therefor
-
- 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
- F16C2208/00—Plastics; Synthetic resins, e.g. rubbers
- F16C2208/20—Thermoplastic resins
- F16C2208/36—Polyarylene ether ketones [PAEK], e.g. PEK, PEEK
-
- 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
- F16C2208/00—Plastics; Synthetic resins, e.g. rubbers
- F16C2208/20—Thermoplastic resins
- F16C2208/52—Polyphenylene sulphide [PPS]
-
- 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
- F16C2300/00—Application independent of particular apparatuses
- F16C2300/02—General use or purpose, i.e. no use, purpose, special adaptation or modification indicated or a wide variety of uses mentioned
-
- 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
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/30—Parts of ball or roller bearings
- F16C33/46—Cages for rollers or needles
- F16C33/49—Cages for rollers or needles comb-shaped
- F16C33/494—Massive or moulded comb cages
- F16C33/495—Massive or moulded comb cages formed as one piece cages, i.e. monoblock comb cages
- F16C33/498—Massive or moulded comb cages formed as one piece cages, i.e. monoblock comb cages made from plastic, e.g. injection moulded comb cages
Definitions
- the present invention relates to a bearing cage and a manufacturing method therefore.
- a bearing cage is manufactured by an injection molding. Specifically, as shown in FIG. 16 , an annular cavity 140 corresponding to a bearing cage, which is a molded article, is formed in an injection mold, and a melted resin material (thermoplastic resin) is injected from a resin injection gate 150 provided at a peripheral edge part of the cavity 140 and is cooled and solidified, so that a bearing cage is manufactured.
- a melted resin material thermoplastic resin
- the melted resin injected in the cavity 140 is split into two flows toward both sides in the cavity 140 with respect to a circumferential direction, the two flows are merged and joined at an opposite position radially facing the resin injection gate 150 , so that a weld line 100 W is formed.
- the resin bearing cage injection-molded in this way is simply obtained by the melted resin integrally welded, the melted resin is not uniformly mixed, so that the strength is decreased at the weld line 100 W.
- the reinforcing fiber material such as glass fiber, carbon fiber, metal fiber and the like is added to the melted resin as a reinforcing material
- the reinforcing fiber material is vertically oriented at the weld line 100 W with respect to a flow direction of the melted resin, so that the reinforcing effect is not realized.
- the reinforcing fiber material is oriented in parallel with the flow direction of the melted resin at a part except the weld line 100 W, a strength difference between the part and the weld line increases.
- the resin bearing cage manufactured by the injection molding is damaged from the weld line with low strength.
- the weld line is formed at a part (for example, a bottom of a pocket, at which an axial thickness is smallest, a curved portion of a corner part at which a circular ring part and a pillar part intersect, and the like) at which stress is most likely to be concentrated, the damage is likely to be generated at the part, so that the durability of the cage is deteriorated. Therefore, in the related art, following measures have been taken.
- Patent Document 1 discloses a method of injecting the melted resin from one gate to perform the injection molding, thereby manufacturing a synthetic resin cage having an odd number of pockets.
- the gate is provided at a position corresponding to a pillar-shaped part, and a part of any one of the melted resins split in two directions through the gate is introduced into a resin reservoir having a volume corresponding to one pocket.
- Patent Document 2 discloses a manufacturing method of a synthetic resin cage, in which a resin composition for cage molding is injection-molded by using a cage injection mold including a first resin reservoir configured to lead to an opening provided at an inner diameter-side of a position coinciding with a weld line position of a cavity and a second resin reservoir adjacent to the first resin reservoir and configured to lead to an opening provided to the cavity.
- a spaced distance between the opening of the second resin reservoir and the opening of the first resin reservoir is less than a maximum width of a pocket of a cage.
- an opening area of the second resin reservoir is less than an opening area of the first resin reservoir.
- Patent Document 3 discloses a manufacturing method of a bearing cage, in which a resin reservoir is provided at both circumferential sides of a weld line position of the cavity or at the weld line position and the melted resin is injection-molded. Thereby, at least a part of the reinforcing fiber material positioned on a weld line surface is oriented perpendicularly to the weld line surface, so that the joint strength of the weld line surface is improved.
- Patent Document 1 Japanese Patent No. 3,652,396B
- Patent Document 2 Japanese Patent No. 5,428,839B
- Patent Document 3 JP-A-2012-219917
- the present invention has been made in view of the above situations, and an object thereof is to provide a bearing cage capable of suppressing an decrease in the strength and a manufacturing method therefor.
- a manufacturing method of a bearing cage that is to be formed by injecting melted resin from one resin injection gate, which is provided at a peripheral edge part of a substantially circular ring-shaped cavity formed in an injection mold, into the cavity,
- bearing cage includes:
- a circumferential distance between the resin reservoir and the weld line is smaller than a circumferential distance between the resin reservoir and the resin injection gate
- a cross-sectional area of a communicating part of the resin reservoir, which is configured to communicate with the pillar part, is equal to or less than a quarter of a cross-sectional area of the resin injection gate.
- the resin reservoir is provided at a first pillar part in the circumferential direction from a position at which the weld line is formed.
- the resin injection gate is arranged at a position deviating from a circumferentially central portion of the pillar part.
- the resin reservoir is provided at the pillar part in only the first region.
- the resin reservoir is provided at the pillar part adjacent to the weld line in the circumferential direction.
- a bearing cage comprising:
- a first cutting mark (resin injection gate) is disposed at the pillar part
- a second cutting mark is disposed at the pillar part in only one of the regions
- a circumferential distance between the second cutting mark and the weld line is smaller than a circumferential distance between the second cutting mark and the first cutting mark
- a cross-sectional area of the second cutting mark is equal to or less than a quarter of a cross-sectional area of the first cutting mark.
- the second cutting mark is provided at a first pillar part in the circumferential direction from a position at which the weld line is formed.
- the first cutting mark is arranged at a position deviating from a circumferentially central portion of the pillar part.
- the second cutting mark is provided at the pillar part in only the first region.
- the second cutting mark is provided at the pillar part adjacent to the weld line in the circumferential direction.
- the resin reservoir is provided at the pillar part in only one of the first and second regions. Therefore, after the melted resin merges, the melted resin is introduced into the resin reservoir, so that a pressure gradient of the melted resin occurs between the weld line and the resin reservoir and a forcible resin flow is caused due to the pressure gradient. As a result, the reinforcing fiber material is suppressed from being oriented perpendicularly to the flow direction at the weld line.
- the strength is a little decreased in the vicinity of a part at which the resin injection gate or the resin reservoir is provided, although the decrease in the strength is less than at a part at which the weld line is formed.
- the resin injection gate or the resin reservoir is provided at the pillar part having an axial thickness larger than the pocket, it is possible to suppress the decrease in the strength of the bearing cage.
- the circumferential distance between the resin reservoir and the weld line is smaller than the circumferential distance between the resin reservoir and the resin injection gate, the forcible resin flow can be easily caused at the weld line after the melted resin merges. As a result, the orientation of the reinforcing fiber material at the weld line is suppressed, so that the strength of the weld line is improved.
- the cross-sectional area of the communicating part of the resin reservoir is equal to or less than a quarter of the cross-sectional area of the resin injection gate, the introduction of the melted resin into the resin reservoir starts after the melted resin merges. Accordingly, it is possible to more securely realize the effect of suppressing the orientation of the reinforcing fiber material by the forcible resin flow at the weld line.
- FIG. 1 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a first embodiment.
- FIG. 2 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a second embodiment.
- FIG. 3 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a third embodiment.
- FIG. 4 is a plan view of a comb-shaped cage manufactured by a manufacturing method of a fourth embodiment.
- FIG. 5 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a fifth embodiment.
- FIG. 6 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a sixth embodiment.
- FIG. 7 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a seventh embodiment.
- FIG. 8 is a plan view of a crown-shaped cage manufactured by a manufacturing method of an eighth embodiment.
- FIG. 9 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a ninth embodiment.
- FIG. 10 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a tenth embodiment.
- FIG. 11 is a plan view of a comb-shaped cage manufactured by a manufacturing method of an eleventh embodiment.
- FIG. 12 depicts a flowing aspect of melted resin in Embodiment 1.
- FIG. 13 depicts a flowing aspect of melted resin in Comparative Example 1.
- FIG. 14 depicts a flowing aspect of melted resin in Comparative Example 2.
- FIG. 15 depicts a flowing aspect of melted resin in Comparative Example 3.
- FIG. 16 is a sectional view of an injection mold that is to be used in a manufacturing method of a bearing cage of the related art.
- FIG. 1 depicts a bearing cage 1 (which will also be simply referred as ‘cage’, in the below) of a first embodiment.
- the cage 1 is a so-called crown-shaped cage, and includes a substantially circular ring-shaped base part 10 , an odd number of pillar parts 20 (thirteen pillar parts, in the first embodiment) spaced with predetermined intervals in a circumferential direction and protruding axially from one axial end side surface 12 of the base part 10 , and an odd number of pockets 30 (thirteen pockets, in the first embodiment), each of which is formed by facing surfaces 22 , 22 of a pair of the pillar parts 20 , 20 adjacent to each other and one axial end side surface 12 of the base part 10 and is configured to hold a rolling element (not shown) of a bearing. That is, the numbers of the pillar parts 20 and the pockets 30 are the same and are also odd, and the pillar parts 20 are provided at both circumferential sides of each of the pockets 30 .
- the cage 1 As a manufacturing method of the cage 1 , one point gate-type injection molding is adopted. Specifically, the cage 1 is formed by injecting melted resin having a reinforcing fiber material added thereto from a resin injection gate (hereinafter, simply referred to as ‘gate’) 51 , which is provided at a peripheral edge part of an inner periphery side of an annular cavity (not shown) formed in an injection mold, into the cavity and cooling and solidifying the melted resin.
- a resin injection gate hereinafter, simply referred to as ‘gate’) 51 , which is provided at a peripheral edge part of an inner periphery side of an annular cavity (not shown) formed in an injection mold
- a resin composition in which a reinforcing fiber material (for example, glass fiber or carbon fiber) of 10 to 50 wt % is added to a polyamide-based resin such as 46 nylon and 66 nylon or a resin such as polybutylene terephthalate, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyethernitrile (PEN) and the like is used.
- a resin composition in which a reinforcing fiber material (for example, glass fiber or carbon fiber) of 10 to 50 wt % is added to a polyamide-based resin such as 46 nylon and 66 nylon or a resin such as polybutylene terephthalate, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyethernitrile (PEN) and the like is used.
- the gate 51 is supplied with the melted resin from a substantially cylindrical sprue 55 via a substantially cylindrical runner 53 .
- the sprue 55 axially extends at a substantial center of the cage 1 (cavity), and is connected to the runner 53 .
- the gate 51 is disposed at a position corresponding to the pillar part 20 , i.e., a position at which it overlaps with the pillar part 20 in the circumferential direction. Therefore, the melted resin injected from the gate 51 into the cavity and flowing toward both circumferential sides is joined each other on a bottom of the pocket 30 radially facing the pillar part 20 at which the gate 51 is provided. In this case, a weld line W (which is shown with a broken line in FIG. 1 ) is formed on the bottom of the pocket 30 .
- the cage 1 (cavity) is bisected into first and second regions S 1 and S 2 by an imaginary line M connecting the gate 51 and the weld line W.
- a resin reservoir 40 that can store therein the melted resin is provided on an outer peripheral surface of the pillar part 20 in only one region (the first region S 1 , in the first embodiment) of the first and second regions S 1 and S 2 . Therefore, when the resin reservoir 40 is provided at the pillar part 20 in the first region S 1 , like the first embodiment, the resin reservoir 40 is not provided in the second region S 2 . According to the resin reservoir 40 provided in this way, after the melted resin merges to form the weld line W, the melted resin is introduced into the resin reservoir 40 .
- a circumferential distance between the resin reservoir 40 and the weld line W is set shorter than a circumferential distance between the resin reservoir 40 and the gate 51 .
- the circumferential distance between the resin reservoir 40 and the weld line W is preferably set to be extremely shorter. That is, like the first embodiment, the resin reservoir 40 is preferably provided at the first pillar part 20 (the pillar part 20 adjacent to the pocket 30 in which the weld line W is formed) in the circumferential direction from a position at which the weld line W is formed.
- the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is suppressed and the strength of the weld line W is thus improved.
- a cross-sectional area of a communicating part 42 of the resin reservoir 40 which is configured to communicate with the pillar part 20 , is set to be equal to or less than a quarter of a cross-sectional area of the gate 51 . According to this configuration, after the melted resin merges to form the weld line W, the introduction of the melted resin into the resin reservoir 40 starts. Accordingly, it is possible to more securely realize the effect of suppressing the orientation of the reinforcing fiber material by the forcible resin flow at the weld line W.
- the second embodiment is different from the first embodiment, in that the resin reservoir 40 is provided on an inner peripheral surface of the pillar part 20 .
- the other configurations are similar to the first embodiment, and the similar effects to the first embodiment can be accomplished.
- the third embodiment is different from the first and second embodiments, in that the resin reservoir 40 is provided on the outer peripheral surface of the second pillar part 20 in the circumferential direction from the position at which the weld line W is formed. Also in this configuration, since the circumferential distance between the resin reservoir 40 and the weld line W is set shorter than the circumferential distance between the resin reservoir 40 and the gate 51 , the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is controlled and the strength of the weld line W is thus improved.
- the other configurations and effects are similar to the first and second embodiments.
- FIG. 4 depicts a bearing cage 1 A (which will also be simply referred to as ‘cage’, in the below) of the fourth embodiment.
- the cage 1 A is a so-called comb-shaped cage, and includes a substantially circular ring-shaped base part 10 A, an odd number of pillar parts 20 A (thirteen pillar parts, in the fourth embodiment) spaced with predetermined intervals in a circumferential direction and protruding axially from one axial end side surface 12 A of the base part 10 A, and an odd number of pockets 30 A (thirteen pockets, in the fourth embodiment), each of which is formed by facing surfaces 22 A, 22 A of a pair of the pillar parts 20 A, 20 A adjacent to each other and one axial end side surface 12 A of the base part 10 A and is configured to hold a rolling element (not shown) of a bearing. That is, the numbers of the pillar parts 20 A and the pockets 30 A are the same and are also odd, and the pillar parts 20 A are provided at both circumferential sides of each of
- the gate 51 is disposed at a position corresponding to the pillar part 20 A, i.e., a position at which it overlaps with the pillar part 20 A in the circumferential direction. Therefore, the melted resin injected from the gate 51 into the cavity and flowing toward both circumferential sides is joined each other on a bottom of the pocket 30 A radially facing the pillar part 20 A at which the gate 51 is provided. In this case, a weld line W (which is shown with a broken line in FIG. 4 ) is formed on the bottom of the pocket 30 A.
- the resin reservoir 40 that can store therein the melted resin is provided on an inner peripheral surface of the pillar part 20 A in only the first region S 1 of the first and second regions S 1 and S 2 bisected by the imaginary line M. Also, the circumferential distance between the resin reservoir 40 and the weld line W is set shorter than the circumferential distance between the resin reservoir 40 and the gate 51 .
- the resin reservoir 40 is provided at the first pillar part 20 A (the pillar part 20 A adjacent to the pocket 30 A in which the weld line W is formed) in the circumferential direction from the position at which the weld line W is formed.
- the cross-sectional area of the communicating part 42 of the resin reservoir 40 which is configured to communicate with the pillar part 20 A, is set to be equal to or less than a quarter of the cross-sectional area of the gate 51 .
- FIG. 5 depicts a bearing cage 1 (which will also be simply referred as ‘cage’, in the below) of a fifth embodiment.
- the cage 1 is a so-called crown-shaped cage, and includes a substantially circular ring-shaped base part 10 , an even number of pillar parts 20 (fourteen pillar parts, in the fifth embodiment) spaced with predetermined intervals in a circumferential direction and protruding axially from one axial end side surface 12 of the base part 10 , and an even number of pockets 30 (fourteen pockets, in the fifth embodiment), each of which is formed by facing surfaces 22 , 22 of a pair of the pillar parts 20 , 20 adjacent to each other and one axial end side surface 12 of the base part 10 and is configured to hold a rolling element (not shown) of a bearing. That is, the numbers of the pillar parts 20 and the pockets 30 are the same and are also even, and the pillar parts 20 are provided at both circumferential sides of each of the pockets 30 .
- the cage 1 As a manufacturing method of the cage 1 , one point gate-type injection molding is adopted. Specifically, the cage 1 is formed by injecting melted resin having a reinforcing fiber material added thereto from a resin injection gate (hereinafter, simply referred to as ‘gate’) 51 , which is provided at a peripheral edge part of an inner periphery side of an annular cavity (not shown) formed in an injection mold, into the cavity and cooling and solidifying the melted resin.
- a resin injection gate hereinafter, simply referred to as ‘gate’) 51 , which is provided at a peripheral edge part of an inner periphery side of an annular cavity (not shown) formed in an injection mold
- a resin composition in which a reinforcing fiber material (for example, glass fiber or carbon fiber) of 10 to 50 wt % is added to a polyamide-based resin such as 46 nylon and 66 nylon or a resin such as polybutylene terephthalate, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyethernitrile (PEN) and the like is used.
- a resin composition in which a reinforcing fiber material (for example, glass fiber or carbon fiber) of 10 to 50 wt % is added to a polyamide-based resin such as 46 nylon and 66 nylon or a resin such as polybutylene terephthalate, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyethernitrile (PEN) and the like is used.
- the gate 51 is supplied with the melted resin from a substantially cylindrical sprue 55 via a substantially cylindrical runner 53 .
- the sprue 55 axially extends at a substantial center of the cage 1 (cavity), and is connected to the runner 53 .
- the gate 51 is disposed at a position corresponding to the pillar part 20 , i.e., a position at which it overlaps with the pillar part 20 in the circumferential direction.
- the gate 51 is disposed at a circumferentially central portion of the pillar part 20 . Therefore, the melted resin injected from the gate 51 into the cavity and flowing toward both circumferential sides is joined each other at a circumferentially central portion of the pillar part 20 radially facing the pillar part 20 at which the gate 51 is provided.
- a weld line W (which is shown with a broken line in FIG. 5 ) is formed at the circumferentially central portion of the pillar part 20 .
- the cage 1 (cavity) is bisected into first and second regions S 1 and S 2 by an imaginary line M connecting the gate 51 and the weld line W.
- a resin reservoir 40 that can store therein the melted resin is provided on an outer peripheral surface of the pillar part 20 in only one region (the first region S 1 , in the fifth embodiment) of the first and second regions S 1 and S 2 . Therefore, when the resin reservoir 40 is provided at the pillar part 20 in the first region S 1 , like the fifth embodiment, the resin reservoir 40 is not provided in the second region S 2 . According to the resin reservoir 40 provided in this way, after the melted resin merges to form the weld line W, the melted resin is introduced into the resin reservoir 40 .
- the strength is a little decreased in the vicinity of a part at which the resin injection gate 51 or the resin reservoir 40 is provided, although the decrease in the strength is less than at the part at which the weld line W is formed.
- the resin injection gate 51 or the resin reservoir 40 is provided at the pillar part 20 having an axial thickness larger than the pocket 30 , it is possible to suppress the decrease in the strength of the bearing cage 1 .
- a circumferential distance between the resin reservoir 40 and the weld line W is set shorter than a circumferential distance between the resin reservoir 40 and the gate 51 .
- the circumferential distance between the resin reservoir 40 and the weld line W is preferably set to be extremely shorter. That is, like the fifth embodiment, the resin reservoir 40 is preferably provided at the first pillar part 20 (the pillar part 20 adjacent to the pillar part 20 at which the weld line W is formed) in the circumferential direction from a position at which the weld line W is formed.
- the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is suppressed and the strength of the weld line W is thus improved.
- a cross-sectional area of a communicating part 42 of the resin reservoir 40 which is configured to communicate with the pillar part 20 , is set to be equal to or less than a quarter of a cross-sectional area of the gate 51 . According to this configuration, after the melted resin merges to form the weld line W, the introduction of the melted resin into the resin reservoir 40 starts. Accordingly, it is possible to more securely realize the effect of suppressing the orientation of the reinforcing fiber material by the forcible resin flow at the weld line W.
- the resin reservoir 40 is not limited to the configuration where it is provided on the outer peripheral surface of the pillar part 20 . That is, even when the resin reservoir 40 is provided on an inner peripheral surface of the pillar part 20 , the similar effects can be accomplished.
- the pillar part 20 at which the resin reservoir 40 is provided is not particularly limited inasmuch as the circumferential distance between the resin reservoir 40 and the weld line W is set smaller than the circumferential distance between the resin reservoir 40 and the gate 51 . That is, the resin reservoir 40 may be provided at the second or third pillar part 20 in the circumferential direction from the pillar part 20 at which the weld line W is formed.
- the circumferential distance between the resin reservoir 40 and the weld line W is set smaller than the circumferential distance between the resin reservoir 40 and the gate 51 , the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is controlled and the strength of the weld line W is thus improved.
- the sixth embodiment is different from the fifth embodiment, in that the gate 51 is disposed at a position deviating in one circumferential direction (a counterclockwise direction, in FIG. 6 ) from the circumferentially central portion of the pillar part 20 .
- the melted resin injected from the gate 51 into the cavity and flowing toward both circumferential sides is joined each other at a position radially facing the pillar part 20 at which the gate 51 is provided, and the joined part becomes the weld line W. That is, the weld line W is formed between the circumferentially central portion of the pillar part 20 and the bottom of the pocket 30 in the circumferential direction.
- the bottom of the pocket 30 is a part, which is positioned at a circumferentially central portion of the pocket 30 and at which the axial thickness of the pocket 30 is smallest.
- first and second regions S 1 and S 2 a region including the pillar part 20 L, in which the bottom of the pocket 30 does not exist between the pillar part 20 L and the weld line W, of the pair of pillar parts 20 L, 20 R adjacent to the weld line W in the circumferential direction is set as the first region S 1 .
- the resin reservoir 40 is provided on the outer peripheral surface of the pillar part 20 in only the first region S 1 .
- the resin reservoir 40 is not provided at the pillar part 20 in the second region S 2 .
- the resin reservoir 40 is disposed in this way, so that after the melted resin merges to form the weld line W, the forcible flow of the melted resin is caused at the weld line W in a direction in which a cross-sectional area of a flow path increases (a direction facing toward the first region S 1 ). Accordingly, the orientation of the reinforcing fiber material at the weld line W is suppressed and a region in which the fiber orientation is disturbed is moved to a part of which the cross-sectional area is larger, so that it is possible to further improve the strength of the weld line W.
- the resin reservoir 40 is provided at the pillar part 20 L (the first pillar part 20 L in the circumferential direction from the position at which the weld line W is formed), which is adjacent to the weld line W in the circumferential direction, of the pillar parts 20 in the first region S 1 , the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material of the weld line W is controlled and the strength of the weld line W is thus improved.
- the seventh embodiment is different from the sixth embodiment, in that the resin reservoir 40 is provided on the inner peripheral surface of the pillar part 20 .
- the other configurations are similar to the sixth embodiment, and the similar effects to the sixth embodiment can be accomplished.
- the eighth embodiment is different from the fifth to seventh embodiments, in that the resin reservoir 40 is provided on the outer peripheral surface of the second pillar part 20 in the circumferential direction from the position at which the weld line W is formed.
- the resin reservoir 40 is provided in the first region S 1 , the orientation of the reinforcing fiber material at the weld line W is controlled and a region in which the fiber orientation is disturbed is moved to a part of which the cross-sectional area is larger, so that it is possible to further improve the strength of the weld line W. Also, since the circumferential distance between the resin reservoir 40 and the weld line W is set smaller than the circumferential distance between the resin reservoir 40 and the gate 51 , the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is controlled and the strength of the weld line W is thus improved.
- the other configurations and effects are similar to the above embodiments.
- the ninth embodiment is different from the eighth embodiment, in that the resin reservoir 40 is provided on the inner peripheral surface of the pillar part 20 .
- the other configurations are similar to the eighth embodiment, and the similar effects to the eighth embodiment can be accomplished.
- the tenth embodiment is different from the fifth to ninth embodiments, in that the resin reservoir 40 is provided on the outer peripheral surface of the third pillar part 20 in the circumferential direction from the position at which the weld line W is formed.
- the other configurations are similar to the fifth to ninth embodiments, and the similar effects to the fifth to ninth embodiments can be accomplished.
- the resin reservoir 40 is not limited to the configuration where it is provided on the outer peripheral surface of the pillar part 20 . That is, even when the resin reservoir 40 is provided on the inner peripheral surface of the pillar part 20 , the similar effects can be accomplished.
- the pillar part 20 at which the resin reservoir 40 is provided is not particularly limited inasmuch as the resin reservoir is provided at the pillar part 20 in only the first region S 1 and the circumferential distance between the resin reservoir 40 and the weld line W is set smaller than the circumferential distance between the resin reservoir 40 and the gate 51 .
- FIG. 11 depicts a bearing cage 1 A (which will also be simply referred to as ‘cage’, in the below) of the eleventh embodiment.
- the cage 1 A is a so-called comb-shaped cage, and includes a substantially circular ring-shaped base part 10 A, an even number of pillar parts 20 A (fourteen pillar parts, in the eleventh embodiment) spaced with predetermined intervals in a circumferential direction and protruding axially from one axial end side surface 12 A of the base part 10 A, and an even number of pockets 30 A (fourteen pockets, in the eleventh embodiment), each of which is formed by facing surfaces 22 A, 22 A of a pair of the pillar parts 20 A, 20 A adjacent to each other and one axial end side surface 12 A of the base part 10 A and is configured to hold a rolling element (not shown) of a bearing. That is, the numbers of the pillar parts 20 A and the pockets 30 A are the same and are also even, and the pillar parts 20 A are provided at both circumferential sides of each
- the similar manufacturing method to the fifth to tenth embodiments can be applied.
- the gate 51 is disposed at a position corresponding to the pillar part 20 A, i.e., a position at which it overlaps with the pillar part 20 A in the circumferential direction. Therefore, the melted resin injected from the gate 51 into the cavity and flowing toward both circumferential sides is joined each other at a circumferentially central portion of the pillar part 20 A radially facing the pillar part 20 A at which the gate 51 is provided.
- a weld line W (which is shown with a broken line in FIG. 11 ) is formed at the circumferentially central portion of the pillar part 20 A.
- the resin reservoir 40 that can store therein the melted resin is provided on an inner peripheral surface of the pillar part 20 A in only the first region S 1 of the first and second regions S 1 and S 2 bisected by the imaginary line M. Also, the circumferential distance between the resin reservoir 40 and the weld line W is set shorter than the circumferential distance between the resin reservoir 40 and the gate 51 .
- the resin reservoir 40 is provided at the first pillar part 20 A (the pillar part 20 A adjacent to the pillar part 20 A, at which the weld line W is formed, in the circumferential direction) in the circumferential direction from the pillar part 20 A at which the weld line W is formed.
- the cross-sectional area of the communicating part 42 of the resin reservoir 40 which is configured to communicate with the pillar part 20 A, is set to be equal to or less than 1 ⁇ 4 of the cross-sectional area of the gate 51 .
- the resin reservoir 40 is not limited to the configuration where it is provided on the inner peripheral surface of the pillar part 20 A. That is, even when the resin reservoir 40 is provided on the outer peripheral surface of the pillar part 20 A, the similar effects can be accomplished.
- the pillar part 20 A at which the resin reservoir 40 is provided is not particularly limited inasmuch as the circumferential distance between the resin reservoir 40 and the weld line W is set smaller than the circumferential distance between the resin reservoir 40 and the gate 51 . That is, the resin reservoir 40 may be provided at the second or third pillar part 20 A in the circumferential direction from the pillar part 20 A at which the weld line W is formed.
- the circumferential distance between the resin reservoir 40 and the weld line W is set smaller than the circumferential distance between the resin reservoir 40 and the gate 51 , the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is controlled and the strength of the weld line W is thus improved.
- the manufacturing methods of the crown-shaped cage 1 in accordance with the fifth to tenth embodiments can be applied to the manufacturing method of the comb-shaped cage 1 A.
- the manufacturing method of the bearing cage of the present invention is not limited to the crown-shaped cage 1 and the comb-shaped cage 1 A, and can be applied to a variety of cages.
- a cavity 60 is configured as a simple circular ring model, a diameter (the cross-sectional area) of the resin injection gate 51 is made constant, a diameter (the cross-sectional area) of the communicating part 42 of the resin reservoir 40 is changed, and a flowing state of the melted resin G is analyzed by resin flow analysis software “3D TIMON” available from Toray Engineering Co., Ltd.
- Example 1 Example 2
- Example 3 (FIG. 12) (FIG. 13) (FIG. 14) (FIG. 15) diameter of gate (mm) 1.2 cross-sectional area of gate (mm) 1.13 diameter of communicating part of 0.6 0.8 1 1.2 resin reservoir (mm) cross-sectional area of 0.28 0.50 0.79 1.13 communicating part of resin reservoir (mm) ratio of cross-sectional area of 0.25 0.44 0.69 1.00 communicating part of resin reservoir to cross-sectional area of gate filling pattern
- the melted resin The melted resin is introduced into the resin is not introduced reservoir before merger. into the resin reservoir before merger.
- the bearing cage of the present invention can be applied to a rolling bearing because the decrease in the strength is small and the durability is excellent. That is, since the rolling bearing includes an inner ring, an outer ring, a plurality of rolling elements provided between the inner ring and the outer ring, and a bearing cage configured to rollably keep the rolling elements in pockets and having the excellent durability, it is possible to meet requirements such as high-speed rotation, high load and the like.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Rolling Contact Bearings (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
The resin injection gate is disposed at the pillar part. When the bearing cage is divided into first and second regions by an imaginary line connecting the resin injection gate and a weld to be formed at a position radially facing the resin injection gate, a resin reservoir that can store therein the melted resin is formed at the pillar part in only one of the regions. A circumferential distance between the resin reservoir and the weld is smaller than a circumferential distance between the resin reservoir and the resin injection gate. A cross-sectional area of a communicating part of the resin reservoir, which is configured to communicate with the pillar part, is equal to or less than a quarter of a cross-sectional area of the resin injection gate.
Description
- This application is a divisional of U.S. application Ser. No. 16/076,899, filed Aug. 9, 2018, which claims priority to National Stage Application No. PCT/JP2016/054929, filed Feb. 19, 2016, the disclosures of which are incorporated herein by reference in their entirety.
- The present invention relates to a bearing cage and a manufacturing method therefore.
- In general, a bearing cage is manufactured by an injection molding. Specifically, as shown in
FIG. 16 , anannular cavity 140 corresponding to a bearing cage, which is a molded article, is formed in an injection mold, and a melted resin material (thermoplastic resin) is injected from aresin injection gate 150 provided at a peripheral edge part of thecavity 140 and is cooled and solidified, so that a bearing cage is manufactured. - The melted resin injected in the
cavity 140 is split into two flows toward both sides in thecavity 140 with respect to a circumferential direction, the two flows are merged and joined at an opposite position radially facing theresin injection gate 150, so that aweld line 100W is formed. In general, since the resin bearing cage injection-molded in this way is simply obtained by the melted resin integrally welded, the melted resin is not uniformly mixed, so that the strength is decreased at theweld line 100W. - Also, when a reinforcing fiber material such as glass fiber, carbon fiber, metal fiber and the like is added to the melted resin as a reinforcing material, the reinforcing fiber material is vertically oriented at the
weld line 100W with respect to a flow direction of the melted resin, so that the reinforcing effect is not realized. Also, since the reinforcing fiber material is oriented in parallel with the flow direction of the melted resin at a part except theweld line 100W, a strength difference between the part and the weld line increases. - Therefore, in many cases, the resin bearing cage manufactured by the injection molding is damaged from the weld line with low strength. In particular, when the weld line is formed at a part (for example, a bottom of a pocket, at which an axial thickness is smallest, a curved portion of a corner part at which a circular ring part and a pillar part intersect, and the like) at which stress is most likely to be concentrated, the damage is likely to be generated at the part, so that the durability of the cage is deteriorated. Therefore, in the related art, following measures have been taken.
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Patent Document 1 discloses a method of injecting the melted resin from one gate to perform the injection molding, thereby manufacturing a synthetic resin cage having an odd number of pockets. In the manufacturing method, the gate is provided at a position corresponding to a pillar-shaped part, and a part of any one of the melted resins split in two directions through the gate is introduced into a resin reservoir having a volume corresponding to one pocket. Thereby, it is possible to avoid formation of a weld line at a pocket bottom facing the gate and to merge the melted resins at a pillar part adjacent to the pocket. -
Patent Document 2 discloses a manufacturing method of a synthetic resin cage, in which a resin composition for cage molding is injection-molded by using a cage injection mold including a first resin reservoir configured to lead to an opening provided at an inner diameter-side of a position coinciding with a weld line position of a cavity and a second resin reservoir adjacent to the first resin reservoir and configured to lead to an opening provided to the cavity. A spaced distance between the opening of the second resin reservoir and the opening of the first resin reservoir is less than a maximum width of a pocket of a cage. Also, an opening area of the second resin reservoir is less than an opening area of the first resin reservoir. Thereby, the fiber orientation is controlled by generating a forcible resin flow in the vicinity of the weld line, so that a reinforcing effect of the weld line is improved. - Patent Document 3 discloses a manufacturing method of a bearing cage, in which a resin reservoir is provided at both circumferential sides of a weld line position of the cavity or at the weld line position and the melted resin is injection-molded. Thereby, at least a part of the reinforcing fiber material positioned on a weld line surface is oriented perpendicularly to the weld line surface, so that the joint strength of the weld line surface is improved.
- Patent Document 1: Japanese Patent No. 3,652,396B
- Patent Document 2: Japanese Patent No. 5,428,839B
- Patent Document 3: JP-A-2012-219917
- However, according to the manufacturing method disclosed in
Patent Document 1, since the pillar part is formed with the weld line portion at which the melted resin is simply integrally welded, the strength may be insufficient depending on using conditions. - According to the manufacturing method disclosed in
Patent Document 2, since the first resin reservoir is provided at the part coinciding with the weld line position, the reinforcing fiber material is likely to be oriented perpendicularly to the flow direction in the vicinity of the opening of the first resin reservoir, so that the reinforcing effect is not sufficiently obtained. - According to the manufacturing method disclosed in Patent Document 3, in the case that the resin reservoirs are provided at both the circumferential sides of the weld line, since a pressure gradient of the melted resin is decreased in the vicinity of the weld line, the effect of causing the forcible resin flow is reduced. Also, in the case that the resin reservoir is provided at the weld line position, since the reinforcing fiber material is likely to be oriented perpendicularly to the flow direction in the vicinity of the opening of the resin reservoir, the reinforcing effect is not sufficiently obtained.
- The present invention has been made in view of the above situations, and an object thereof is to provide a bearing cage capable of suppressing an decrease in the strength and a manufacturing method therefor.
- The above object of the present invention is accomplished by following configurations.
- (1) A manufacturing method of a bearing cage that is to be formed by injecting melted resin from one resin injection gate, which is provided at a peripheral edge part of a substantially circular ring-shaped cavity formed in an injection mold, into the cavity,
- wherein the bearing cage includes:
-
- a substantially circular ring-shaped base part,
- a plurality and an odd or even number of pillar parts spaced with predetermined intervals in a circumferential direction and protruding axially from one axial end side surface of the base part, and
- pockets whose number is equal to a number of the pillars formed by facing surfaces of a pair of the pillar parts adjacent to each other and one axial end side surface of the base part,
- wherein the resin injection gate is disposed at the pillar part,
- wherein when the bearing cage is divided into first and second regions by an imaginary line connecting the resin injection gate and a weld line to be formed at a position radially facing the resin injection gate, a resin reservoir that can store therein the melted resin is formed at the pillar part in only one of the regions,
- wherein a circumferential distance between the resin reservoir and the weld line is smaller than a circumferential distance between the resin reservoir and the resin injection gate, and
- wherein a cross-sectional area of a communicating part of the resin reservoir, which is configured to communicate with the pillar part, is equal to or less than a quarter of a cross-sectional area of the resin injection gate.
- (2) The manufacturing method of a bearing cage according to the above (1),
- wherein a plurality and an odd number of the pillar parts is provided, and
- wherein the resin reservoir is provided at a first pillar part in the circumferential direction from a position at which the weld line is formed.
- (3) The manufacturing method of a bearing cage according to the above (1),
- wherein a plurality and an even number of the pillar parts is provided, and
- wherein the resin injection gate is arranged at a position deviating from a circumferentially central portion of the pillar part.
- (4) The manufacturing method of a bearing cage according to the above (3),
- wherein when a region including the pillar part, in which a bottom of the pocket does not exist between the pillar part and the weld line, of a pair of the pillar parts adjacent to the weld line in the circumferential direction is set as the first region, the resin reservoir is provided at the pillar part in only the first region.
- (5) The manufacturing method of a bearing cage according to one of the above (1), (3) and (4),
- wherein the resin reservoir is provided at the pillar part adjacent to the weld line in the circumferential direction.
- (6) A bearing cage manufactured by the manufacturing method of a bearing cage according to one of the above (1) to (5).
(7) A bearing cage comprising: - a substantially circular ring-shaped base part;
- a plurality and an odd or even number of pillar parts spaced with predetermined intervals in a circumferential direction and protruding axially from one axial end side surface of the base part; and
- pockets whose number is equal to a number of the pillars formed by facing surfaces of a pair of the pillar parts adjacent to each other and one axial end side surface of the base part;
- wherein a first cutting mark (resin injection gate) is disposed at the pillar part,
- wherein a weld line is formed at a position radially facing the first cutting mark,
- wherein when the bearing cage is divided into first and second regions by an imaginary line connecting the first cutting mark and the weld line, a second cutting mark (resin reservoir) is disposed at the pillar part in only one of the regions,
- wherein a circumferential distance between the second cutting mark and the weld line is smaller than a circumferential distance between the second cutting mark and the first cutting mark, and
- wherein a cross-sectional area of the second cutting mark is equal to or less than a quarter of a cross-sectional area of the first cutting mark.
- (8) The bearing cage according to the above (7),
- wherein a plurality and an odd number of the pillar parts is provided, and
- wherein the second cutting mark is provided at a first pillar part in the circumferential direction from a position at which the weld line is formed.
- (9) The bearing cage according to the above (7),
- wherein a plurality and an even number of the pillar parts is provided, and
- wherein the first cutting mark is arranged at a position deviating from a circumferentially central portion of the pillar part.
- (10) The bearing cage according to the above (9),
- wherein when a region including the pillar part, in which a bottom of the pocket does not exist between the pillar part and the weld line, of a pair of the pillar parts adjacent to the weld line in the circumferential direction is set as the first region, the second cutting mark is provided at the pillar part in only the first region.
- (11) The bearing cage according to one of the above (7), (9), (10),
- wherein the second cutting mark is provided at the pillar part adjacent to the weld line in the circumferential direction.
- According to the bearing cage and the manufacturing method therefor of the present invention, the resin reservoir is provided at the pillar part in only one of the first and second regions. Therefore, after the melted resin merges, the melted resin is introduced into the resin reservoir, so that a pressure gradient of the melted resin occurs between the weld line and the resin reservoir and a forcible resin flow is caused due to the pressure gradient. As a result, the reinforcing fiber material is suppressed from being oriented perpendicularly to the flow direction at the weld line.
- Also, the strength is a little decreased in the vicinity of a part at which the resin injection gate or the resin reservoir is provided, although the decrease in the strength is less than at a part at which the weld line is formed. However, since the resin injection gate or the resin reservoir is provided at the pillar part having an axial thickness larger than the pocket, it is possible to suppress the decrease in the strength of the bearing cage.
- Also, since the circumferential distance between the resin reservoir and the weld line is smaller than the circumferential distance between the resin reservoir and the resin injection gate, the forcible resin flow can be easily caused at the weld line after the melted resin merges. As a result, the orientation of the reinforcing fiber material at the weld line is suppressed, so that the strength of the weld line is improved.
- Also, since the cross-sectional area of the communicating part of the resin reservoir is equal to or less than a quarter of the cross-sectional area of the resin injection gate, the introduction of the melted resin into the resin reservoir starts after the melted resin merges. Accordingly, it is possible to more securely realize the effect of suppressing the orientation of the reinforcing fiber material by the forcible resin flow at the weld line.
-
FIG. 1 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a first embodiment. -
FIG. 2 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a second embodiment. -
FIG. 3 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a third embodiment. -
FIG. 4 is a plan view of a comb-shaped cage manufactured by a manufacturing method of a fourth embodiment. -
FIG. 5 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a fifth embodiment. -
FIG. 6 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a sixth embodiment. -
FIG. 7 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a seventh embodiment. -
FIG. 8 is a plan view of a crown-shaped cage manufactured by a manufacturing method of an eighth embodiment. -
FIG. 9 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a ninth embodiment. -
FIG. 10 is a plan view of a crown-shaped cage manufactured by a manufacturing method of a tenth embodiment. -
FIG. 11 is a plan view of a comb-shaped cage manufactured by a manufacturing method of an eleventh embodiment. -
FIG. 12 depicts a flowing aspect of melted resin inEmbodiment 1. -
FIG. 13 depicts a flowing aspect of melted resin in Comparative Example 1. -
FIG. 14 depicts a flowing aspect of melted resin in Comparative Example 2. -
FIG. 15 depicts a flowing aspect of melted resin in Comparative Example 3. -
FIG. 16 is a sectional view of an injection mold that is to be used in a manufacturing method of a bearing cage of the related art. - Hereinafter, each embodiment of a bearing cage and a manufacturing method therefor of the present invention will be described in detail with reference to the drawings.
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FIG. 1 depicts a bearing cage 1 (which will also be simply referred as ‘cage’, in the below) of a first embodiment. Thecage 1 is a so-called crown-shaped cage, and includes a substantially circular ring-shapedbase part 10, an odd number of pillar parts 20 (thirteen pillar parts, in the first embodiment) spaced with predetermined intervals in a circumferential direction and protruding axially from one axialend side surface 12 of thebase part 10, and an odd number of pockets 30 (thirteen pockets, in the first embodiment), each of which is formed by facingsurfaces pillar parts end side surface 12 of thebase part 10 and is configured to hold a rolling element (not shown) of a bearing. That is, the numbers of thepillar parts 20 and thepockets 30 are the same and are also odd, and thepillar parts 20 are provided at both circumferential sides of each of thepockets 30. - As a manufacturing method of the
cage 1, one point gate-type injection molding is adopted. Specifically, thecage 1 is formed by injecting melted resin having a reinforcing fiber material added thereto from a resin injection gate (hereinafter, simply referred to as ‘gate’) 51, which is provided at a peripheral edge part of an inner periphery side of an annular cavity (not shown) formed in an injection mold, into the cavity and cooling and solidifying the melted resin. As the resin material, a resin composition in which a reinforcing fiber material (for example, glass fiber or carbon fiber) of 10 to 50 wt % is added to a polyamide-based resin such as 46 nylon and 66 nylon or a resin such as polybutylene terephthalate, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyethernitrile (PEN) and the like is used. Meanwhile, inFIG. 1 , although the cavity is not shown, an internal structure thereof is substantially the same as the structure of thecage 1. - The
gate 51 is supplied with the melted resin from a substantiallycylindrical sprue 55 via a substantiallycylindrical runner 53. Thesprue 55 axially extends at a substantial center of the cage 1 (cavity), and is connected to therunner 53. - The
gate 51 is disposed at a position corresponding to thepillar part 20, i.e., a position at which it overlaps with thepillar part 20 in the circumferential direction. Therefore, the melted resin injected from thegate 51 into the cavity and flowing toward both circumferential sides is joined each other on a bottom of thepocket 30 radially facing thepillar part 20 at which thegate 51 is provided. In this case, a weld line W (which is shown with a broken line inFIG. 1 ) is formed on the bottom of thepocket 30. - Here, the cage 1 (cavity) is bisected into first and second regions S1 and S2 by an imaginary line M connecting the
gate 51 and the weld line W. At this time, aresin reservoir 40 that can store therein the melted resin is provided on an outer peripheral surface of thepillar part 20 in only one region (the first region S1, in the first embodiment) of the first and second regions S1 and S2. Therefore, when theresin reservoir 40 is provided at thepillar part 20 in the first region S1, like the first embodiment, theresin reservoir 40 is not provided in the second region S2. According to theresin reservoir 40 provided in this way, after the melted resin merges to form the weld line W, the melted resin is introduced into theresin reservoir 40. Therefore, a pressure gradient of the melted resin occurs between the weld line W and theresin reservoir 40 and a forcible resin flow is caused due to the pressure gradient, so that the reinforcing fiber material is suppressed from being oriented perpendicularly to the flow direction at the weld line W. - A circumferential distance between the
resin reservoir 40 and the weld line W is set shorter than a circumferential distance between theresin reservoir 40 and thegate 51. In the meantime, the circumferential distance between theresin reservoir 40 and the weld line W is preferably set to be extremely shorter. That is, like the first embodiment, theresin reservoir 40 is preferably provided at the first pillar part 20 (thepillar part 20 adjacent to thepocket 30 in which the weld line W is formed) in the circumferential direction from a position at which the weld line W is formed. Thereby, the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is suppressed and the strength of the weld line W is thus improved. - A cross-sectional area of a communicating
part 42 of theresin reservoir 40, which is configured to communicate with thepillar part 20, is set to be equal to or less than a quarter of a cross-sectional area of thegate 51. According to this configuration, after the melted resin merges to form the weld line W, the introduction of the melted resin into theresin reservoir 40 starts. Accordingly, it is possible to more securely realize the effect of suppressing the orientation of the reinforcing fiber material by the forcible resin flow at the weld line W. - Subsequently, a manufacturing method of a bearing cage in accordance with a second embodiment of the present invention is described with reference to the drawing.
- As shown in
FIG. 2 , the second embodiment is different from the first embodiment, in that theresin reservoir 40 is provided on an inner peripheral surface of thepillar part 20. The other configurations are similar to the first embodiment, and the similar effects to the first embodiment can be accomplished. - Subsequently, a manufacturing method of a bearing cage in accordance with a third embodiment of the present invention is described with reference to the drawing.
- As shown in
FIG. 3 , the third embodiment is different from the first and second embodiments, in that theresin reservoir 40 is provided on the outer peripheral surface of thesecond pillar part 20 in the circumferential direction from the position at which the weld line W is formed. Also in this configuration, since the circumferential distance between theresin reservoir 40 and the weld line W is set shorter than the circumferential distance between theresin reservoir 40 and thegate 51, the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is controlled and the strength of the weld line W is thus improved. The other configurations and effects are similar to the first and second embodiments. - Subsequently, a manufacturing method of a bearing cage in accordance with a fourth embodiment of the present invention is described with reference to the drawing.
-
FIG. 4 depicts abearing cage 1A (which will also be simply referred to as ‘cage’, in the below) of the fourth embodiment. Thecage 1A is a so-called comb-shaped cage, and includes a substantially circular ring-shapedbase part 10A, an odd number ofpillar parts 20A (thirteen pillar parts, in the fourth embodiment) spaced with predetermined intervals in a circumferential direction and protruding axially from one axialend side surface 12A of thebase part 10A, and an odd number ofpockets 30A (thirteen pockets, in the fourth embodiment), each of which is formed by facingsurfaces pillar parts end side surface 12A of thebase part 10A and is configured to hold a rolling element (not shown) of a bearing. That is, the numbers of thepillar parts 20A and thepockets 30A are the same and are also odd, and thepillar parts 20A are provided at both circumferential sides of each of thepockets 30A. - Also for the comb-shaped
cage 1A, the similar manufacturing method to the embodiments can be applied. - That is, the
gate 51 is disposed at a position corresponding to thepillar part 20A, i.e., a position at which it overlaps with thepillar part 20A in the circumferential direction. Therefore, the melted resin injected from thegate 51 into the cavity and flowing toward both circumferential sides is joined each other on a bottom of thepocket 30A radially facing thepillar part 20A at which thegate 51 is provided. In this case, a weld line W (which is shown with a broken line inFIG. 4 ) is formed on the bottom of thepocket 30A. - The
resin reservoir 40 that can store therein the melted resin is provided on an inner peripheral surface of thepillar part 20A in only the first region S1 of the first and second regions S1 and S2 bisected by the imaginary line M. Also, the circumferential distance between theresin reservoir 40 and the weld line W is set shorter than the circumferential distance between theresin reservoir 40 and thegate 51. In the fourth embodiment, theresin reservoir 40 is provided at thefirst pillar part 20A (thepillar part 20A adjacent to thepocket 30A in which the weld line W is formed) in the circumferential direction from the position at which the weld line W is formed. Also, the cross-sectional area of the communicatingpart 42 of theresin reservoir 40, which is configured to communicate with thepillar part 20A, is set to be equal to or less than a quarter of the cross-sectional area of thegate 51. - As described above, also in the manufacturing method of the comb-shaped
cage 1A, the similar effects to the embodiments can be accomplished. -
FIG. 5 depicts a bearing cage 1 (which will also be simply referred as ‘cage’, in the below) of a fifth embodiment. Thecage 1 is a so-called crown-shaped cage, and includes a substantially circular ring-shapedbase part 10, an even number of pillar parts 20 (fourteen pillar parts, in the fifth embodiment) spaced with predetermined intervals in a circumferential direction and protruding axially from one axialend side surface 12 of thebase part 10, and an even number of pockets 30 (fourteen pockets, in the fifth embodiment), each of which is formed by facingsurfaces pillar parts end side surface 12 of thebase part 10 and is configured to hold a rolling element (not shown) of a bearing. That is, the numbers of thepillar parts 20 and thepockets 30 are the same and are also even, and thepillar parts 20 are provided at both circumferential sides of each of thepockets 30. - As a manufacturing method of the
cage 1, one point gate-type injection molding is adopted. Specifically, thecage 1 is formed by injecting melted resin having a reinforcing fiber material added thereto from a resin injection gate (hereinafter, simply referred to as ‘gate’) 51, which is provided at a peripheral edge part of an inner periphery side of an annular cavity (not shown) formed in an injection mold, into the cavity and cooling and solidifying the melted resin. As the resin material, a resin composition in which a reinforcing fiber material (for example, glass fiber or carbon fiber) of 10 to 50 wt % is added to a polyamide-based resin such as 46 nylon and 66 nylon or a resin such as polybutylene terephthalate, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyethernitrile (PEN) and the like is used. Meanwhile, inFIG. 5 , although the cavity is not shown, an internal structure thereof is substantially the same as the structure of thecage 1. - The
gate 51 is supplied with the melted resin from a substantiallycylindrical sprue 55 via a substantiallycylindrical runner 53. Thesprue 55 axially extends at a substantial center of the cage 1 (cavity), and is connected to therunner 53. - The
gate 51 is disposed at a position corresponding to thepillar part 20, i.e., a position at which it overlaps with thepillar part 20 in the circumferential direction. Particularly, in the fifth embodiment, thegate 51 is disposed at a circumferentially central portion of thepillar part 20. Therefore, the melted resin injected from thegate 51 into the cavity and flowing toward both circumferential sides is joined each other at a circumferentially central portion of thepillar part 20 radially facing thepillar part 20 at which thegate 51 is provided. In this case, a weld line W (which is shown with a broken line inFIG. 5 ) is formed at the circumferentially central portion of thepillar part 20. - Here, the cage 1 (cavity) is bisected into first and second regions S1 and S2 by an imaginary line M connecting the
gate 51 and the weld line W. At this time, aresin reservoir 40 that can store therein the melted resin is provided on an outer peripheral surface of thepillar part 20 in only one region (the first region S1, in the fifth embodiment) of the first and second regions S1 and S2. Therefore, when theresin reservoir 40 is provided at thepillar part 20 in the first region S1, like the fifth embodiment, theresin reservoir 40 is not provided in the second region S2. According to theresin reservoir 40 provided in this way, after the melted resin merges to form the weld line W, the melted resin is introduced into theresin reservoir 40. Therefore, a pressure gradient of the melted resin occurs between the weld line W and theresin reservoir 40 and a forcible resin flow is caused due to the pressure gradient, so that the reinforcing fiber material is suppressed from being oriented perpendicularly to the flow direction at the weld line W. - Also, the strength is a little decreased in the vicinity of a part at which the
resin injection gate 51 or theresin reservoir 40 is provided, although the decrease in the strength is less than at the part at which the weld line W is formed. However, since theresin injection gate 51 or theresin reservoir 40 is provided at thepillar part 20 having an axial thickness larger than thepocket 30, it is possible to suppress the decrease in the strength of the bearingcage 1. - A circumferential distance between the
resin reservoir 40 and the weld line W is set shorter than a circumferential distance between theresin reservoir 40 and thegate 51. In the meantime, the circumferential distance between theresin reservoir 40 and the weld line W is preferably set to be extremely shorter. That is, like the fifth embodiment, theresin reservoir 40 is preferably provided at the first pillar part 20 (thepillar part 20 adjacent to thepillar part 20 at which the weld line W is formed) in the circumferential direction from a position at which the weld line W is formed. Thereby, the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is suppressed and the strength of the weld line W is thus improved. - A cross-sectional area of a communicating
part 42 of theresin reservoir 40, which is configured to communicate with thepillar part 20, is set to be equal to or less than a quarter of a cross-sectional area of thegate 51. According to this configuration, after the melted resin merges to form the weld line W, the introduction of the melted resin into theresin reservoir 40 starts. Accordingly, it is possible to more securely realize the effect of suppressing the orientation of the reinforcing fiber material by the forcible resin flow at the weld line W. - In the meantime, the
resin reservoir 40 is not limited to the configuration where it is provided on the outer peripheral surface of thepillar part 20. That is, even when theresin reservoir 40 is provided on an inner peripheral surface of thepillar part 20, the similar effects can be accomplished. - Also, the
pillar part 20 at which theresin reservoir 40 is provided is not particularly limited inasmuch as the circumferential distance between theresin reservoir 40 and the weld line W is set smaller than the circumferential distance between theresin reservoir 40 and thegate 51. That is, theresin reservoir 40 may be provided at the second orthird pillar part 20 in the circumferential direction from thepillar part 20 at which the weld line W is formed. Also in this case, since the circumferential distance between theresin reservoir 40 and the weld line W is set smaller than the circumferential distance between theresin reservoir 40 and thegate 51, the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is controlled and the strength of the weld line W is thus improved. - Subsequently, a manufacturing method of a bearing cage in accordance with a sixth embodiment of the present invention is described with reference to the drawing.
- As shown in
FIG. 6 , the sixth embodiment is different from the fifth embodiment, in that thegate 51 is disposed at a position deviating in one circumferential direction (a counterclockwise direction, inFIG. 6 ) from the circumferentially central portion of thepillar part 20. In this case, the melted resin injected from thegate 51 into the cavity and flowing toward both circumferential sides is joined each other at a position radially facing thepillar part 20 at which thegate 51 is provided, and the joined part becomes the weld line W. That is, the weld line W is formed between the circumferentially central portion of thepillar part 20 and the bottom of thepocket 30 in the circumferential direction. In the meantime, the bottom of thepocket 30 is a part, which is positioned at a circumferentially central portion of thepocket 30 and at which the axial thickness of thepocket 30 is smallest. - Here, regarding the first and second regions S1 and S2, a region including the
pillar part 20L, in which the bottom of thepocket 30 does not exist between thepillar part 20L and the weld line W, of the pair ofpillar parts resin reservoir 40 is provided on the outer peripheral surface of thepillar part 20 in only the first region S1. On the other hand, theresin reservoir 40 is not provided at thepillar part 20 in the second region S2. - The
resin reservoir 40 is disposed in this way, so that after the melted resin merges to form the weld line W, the forcible flow of the melted resin is caused at the weld line W in a direction in which a cross-sectional area of a flow path increases (a direction facing toward the first region S1). Accordingly, the orientation of the reinforcing fiber material at the weld line W is suppressed and a region in which the fiber orientation is disturbed is moved to a part of which the cross-sectional area is larger, so that it is possible to further improve the strength of the weld line W. - Particularly, in the sixth embodiment, since the
resin reservoir 40 is provided at thepillar part 20L (thefirst pillar part 20L in the circumferential direction from the position at which the weld line W is formed), which is adjacent to the weld line W in the circumferential direction, of thepillar parts 20 in the first region S1, the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material of the weld line W is controlled and the strength of the weld line W is thus improved. - Subsequently, a manufacturing method of a bearing cage in accordance with a seventh embodiment of the present invention is described with reference to the drawing.
- As shown in
FIG. 7 , the seventh embodiment is different from the sixth embodiment, in that theresin reservoir 40 is provided on the inner peripheral surface of thepillar part 20. The other configurations are similar to the sixth embodiment, and the similar effects to the sixth embodiment can be accomplished. - Subsequently, a manufacturing method of a bearing cage in accordance with an eighth embodiment of the present invention is described with reference to the drawing.
- As shown in
FIG. 8 , the eighth embodiment is different from the fifth to seventh embodiments, in that theresin reservoir 40 is provided on the outer peripheral surface of thesecond pillar part 20 in the circumferential direction from the position at which the weld line W is formed. - Also in this configuration, since the
resin reservoir 40 is provided in the first region S1, the orientation of the reinforcing fiber material at the weld line W is controlled and a region in which the fiber orientation is disturbed is moved to a part of which the cross-sectional area is larger, so that it is possible to further improve the strength of the weld line W. Also, since the circumferential distance between theresin reservoir 40 and the weld line W is set smaller than the circumferential distance between theresin reservoir 40 and thegate 51, the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is controlled and the strength of the weld line W is thus improved. The other configurations and effects are similar to the above embodiments. - Subsequently, a manufacturing method of a bearing cage in accordance with a ninth embodiment of the present invention is described with reference to the drawing.
- As shown in
FIG. 9 , the ninth embodiment is different from the eighth embodiment, in that theresin reservoir 40 is provided on the inner peripheral surface of thepillar part 20. The other configurations are similar to the eighth embodiment, and the similar effects to the eighth embodiment can be accomplished. - Subsequently, a manufacturing method of a bearing cage in accordance with a tenth embodiment of the present invention is described with reference to the drawing.
- As shown in
FIG. 10 , the tenth embodiment is different from the fifth to ninth embodiments, in that theresin reservoir 40 is provided on the outer peripheral surface of thethird pillar part 20 in the circumferential direction from the position at which the weld line W is formed. The other configurations are similar to the fifth to ninth embodiments, and the similar effects to the fifth to ninth embodiments can be accomplished. - In the meantime, the
resin reservoir 40 is not limited to the configuration where it is provided on the outer peripheral surface of thepillar part 20. That is, even when theresin reservoir 40 is provided on the inner peripheral surface of thepillar part 20, the similar effects can be accomplished. - Also, the
pillar part 20 at which theresin reservoir 40 is provided is not particularly limited inasmuch as the resin reservoir is provided at thepillar part 20 in only the first region S1 and the circumferential distance between theresin reservoir 40 and the weld line W is set smaller than the circumferential distance between theresin reservoir 40 and thegate 51. - Subsequently, a manufacturing method of a bearing cage in accordance with an eleventh embodiment of the present invention is described with reference to the drawing.
-
FIG. 11 depicts abearing cage 1A (which will also be simply referred to as ‘cage’, in the below) of the eleventh embodiment. Thecage 1A is a so-called comb-shaped cage, and includes a substantially circular ring-shapedbase part 10A, an even number ofpillar parts 20A (fourteen pillar parts, in the eleventh embodiment) spaced with predetermined intervals in a circumferential direction and protruding axially from one axialend side surface 12A of thebase part 10A, and an even number ofpockets 30A (fourteen pockets, in the eleventh embodiment), each of which is formed by facingsurfaces pillar parts end side surface 12A of thebase part 10A and is configured to hold a rolling element (not shown) of a bearing. That is, the numbers of thepillar parts 20A and thepockets 30A are the same and are also even, and thepillar parts 20A are provided at both circumferential sides of each of thepockets 30A. - Also for the comb-shaped
cage 1A, the similar manufacturing method to the fifth to tenth embodiments can be applied. - That is, the
gate 51 is disposed at a position corresponding to thepillar part 20A, i.e., a position at which it overlaps with thepillar part 20A in the circumferential direction. Therefore, the melted resin injected from thegate 51 into the cavity and flowing toward both circumferential sides is joined each other at a circumferentially central portion of thepillar part 20A radially facing thepillar part 20A at which thegate 51 is provided. In this case, a weld line W (which is shown with a broken line inFIG. 11 ) is formed at the circumferentially central portion of thepillar part 20A. - The
resin reservoir 40 that can store therein the melted resin is provided on an inner peripheral surface of thepillar part 20A in only the first region S1 of the first and second regions S1 and S2 bisected by the imaginary line M. Also, the circumferential distance between theresin reservoir 40 and the weld line W is set shorter than the circumferential distance between theresin reservoir 40 and thegate 51. In the eleventh embodiment, theresin reservoir 40 is provided at thefirst pillar part 20A (thepillar part 20A adjacent to thepillar part 20A, at which the weld line W is formed, in the circumferential direction) in the circumferential direction from thepillar part 20A at which the weld line W is formed. Also, the cross-sectional area of the communicatingpart 42 of theresin reservoir 40, which is configured to communicate with thepillar part 20A, is set to be equal to or less than ¼ of the cross-sectional area of thegate 51. - As described above, also in the manufacturing method of the comb-shaped
cage 1A, the similar effects to the fifth to tenth embodiments can be accomplished. - In the meantime, the
resin reservoir 40 is not limited to the configuration where it is provided on the inner peripheral surface of thepillar part 20A. That is, even when theresin reservoir 40 is provided on the outer peripheral surface of thepillar part 20A, the similar effects can be accomplished. - Also, the
pillar part 20A at which theresin reservoir 40 is provided is not particularly limited inasmuch as the circumferential distance between theresin reservoir 40 and the weld line W is set smaller than the circumferential distance between theresin reservoir 40 and thegate 51. That is, theresin reservoir 40 may be provided at the second orthird pillar part 20A in the circumferential direction from thepillar part 20A at which the weld line W is formed. Also in this case, since the circumferential distance between theresin reservoir 40 and the weld line W is set smaller than the circumferential distance between theresin reservoir 40 and thegate 51, the forcible resin flow can be easily caused at the weld line W after the melted resin merges, so that the orientation of the reinforcing fiber material at the weld line W is controlled and the strength of the weld line W is thus improved. - Also, the manufacturing methods of the crown-shaped
cage 1 in accordance with the fifth to tenth embodiments can be applied to the manufacturing method of the comb-shapedcage 1A. - Like this, the manufacturing method of the bearing cage of the present invention is not limited to the crown-shaped
cage 1 and the comb-shapedcage 1A, and can be applied to a variety of cages. - Subsequently, an analysis result of a relation between the cross-sectional area of the communicating
part 42 of theresin reservoir 40 and the cross-sectional area of theresin injection gate 51 is described. - As shown in
FIGS. 12 to 15 and Table 1, inEmbodiment 1 and Comparative Examples 1 to 3, acavity 60 is configured as a simple circular ring model, a diameter (the cross-sectional area) of theresin injection gate 51 is made constant, a diameter (the cross-sectional area) of the communicatingpart 42 of theresin reservoir 40 is changed, and a flowing state of the melted resin G is analyzed by resin flow analysis software “3D TIMON” available from Toray Engineering Co., Ltd. -
TABLE 1 Comparative Comparative Comparative Embodiment 1 Example 1 Example 2 Example 3 (FIG. 12) (FIG. 13) (FIG. 14) (FIG. 15) diameter of gate (mm) 1.2 cross-sectional area of gate (mm) 1.13 diameter of communicating part of 0.6 0.8 1 1.2 resin reservoir (mm) cross-sectional area of 0.28 0.50 0.79 1.13 communicating part of resin reservoir (mm) ratio of cross-sectional area of 0.25 0.44 0.69 1.00 communicating part of resin reservoir to cross-sectional area of gate filling pattern The melted resin The melted resin is introduced into the resin is not introduced reservoir before merger. into the resin reservoir before merger. - As shown in Comparative Examples 1 to 3 of
FIGS. 13 to 15 , when the ratio of the cross-sectional area of the communicatingpart 42 to the cross-sectional area of theresin injection gate 51 is 0.44 to 1.00, the introduction of the melted resin G into theresin reservoir 40 starts before the melted resin G merges each other. In this case, the effect of causing the forcible resin flow at the weld line W after the melted resin G merges is reduced, so that it is difficult to realize the effect of controlling the orientation of the reinforcing fiber material at the weld line W. - On the other hand, as shown in Embodiment of
FIG. 12 , when the ratio of the cross-sectional area of the communicatingpart 42 to the cross-sectional area of theresin injection gate 51 is 0.25, the melted resin G is not introduced into theresin reservoir 40 until the melted resin G merges. For this reason, after the melted resin G merges to form the weld line W, the effect of causing the forcible resin flow at the weld line W is large, so that the effect of controlling the orientation of the reinforcing fiber material at the weld line W is realized. - Like this, it is clear that when the cross-sectional area of the communicating
part 42 of theresin reservoir 40 is equal to or less than a quarter of the cross-sectional area of theresin injection gate 51, the melted resin G is not introduced into theresin reservoir 40 until the melted resin G merges, so that the effect of controlling the orientation of the reinforcing fiber material at the weld line W is realized. - In the meantime, the present invention is not limited to the respective embodiments, and can be appropriately modified and improved.
- Also, the bearing cage of the present invention can be applied to a rolling bearing because the decrease in the strength is small and the durability is excellent. That is, since the rolling bearing includes an inner ring, an outer ring, a plurality of rolling elements provided between the inner ring and the outer ring, and a bearing cage configured to rollably keep the rolling elements in pockets and having the excellent durability, it is possible to meet requirements such as high-speed rotation, high load and the like.
- 1, 1A: bearing cage
- 10, 10A: base part
- 12, 12A: one axial end side surface
- 20, 20A, 20L, 20R: pillar part
- 22, 22A: surface
- 30, 30A: pocket
- 40: resin reservoir
- 42: communicating part
- 51: resin injection gate
- 53: runner
- 55: sprue
- 60: the cavity
- G: melted resin
- M: imaginary line
- S1: first region
- S2: second region
- W: weld line
Claims (7)
1. A bearing cage comprising:
a substantially circular ring-shaped base part;
a plurality and an odd or even number of pillar parts spaced with predetermined intervals in a circumferential direction and protruding axially from one axial end side surface of the base part; and
pockets whose number is equal to a number of the pillars formed by facing surfaces of a pair of the pillar parts adjacent to each other and one axial end side surface of the base part;
wherein a first cutting mark is disposed at the pillar part,
wherein a weld line is formed at a position radially facing the first cutting mark,
wherein when the bearing cage is divided into first and second regions by an imaginary line connecting the first cutting mark and the weld line, a second cutting mark is disposed at the pillar part in only one of the regions,
wherein a circumferential distance between the second cutting mark and the weld line is smaller than a circumferential distance between the second cutting mark and the first cutting mark, and
wherein a cross-sectional area of the second cutting mark is equal to or less than a quarter of a cross-sectional area of the first cutting mark.
2. The bearing cage according to claim 1 ,
wherein a plurality and an odd number of the pillar parts is provided, and
wherein the second cutting mark is provided at a first pillar part in the circumferential direction from a position at which the weld line is formed.
3. The bearing cage according to claim 1 ,
wherein a plurality and an even number of the pillar parts is provided, and
wherein the first cutting mark is arranged at a position deviating from a circumferentially central portion of the pillar part.
4. The bearing cage according to claim 3 ,
wherein when a region including the pillar part, in which a bottom of the pocket does not exist between the pillar part and the weld line, of a pair of the pillar parts adjacent to the weld line in the circumferential direction is set as the first region, the second cutting mark is provided at the pillar part in only the first region.
5. The bearing cage according to claim 1 ,
wherein the second cutting mark is provided at the pillar part adjacent to the weld line in the circumferential direction.
6. The bearing cage according to claim 3 ,
wherein the second cutting mark is provided at the pillar part adjacent to the weld line in the circumferential direction.
7. The bearing cage according to claim 4 ,
wherein the second cutting mark is provided at the pillar part adjacent to the weld line in the circumferential direction.
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US17/890,838 US20220388209A1 (en) | 2016-02-19 | 2022-08-18 | Bearing cage and manufacturing method therefor |
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US201816076899A | 2018-08-09 | 2018-08-09 | |
US17/890,838 US20220388209A1 (en) | 2016-02-19 | 2022-08-18 | Bearing cage and manufacturing method therefor |
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US17/890,838 Pending US20220388209A1 (en) | 2016-02-19 | 2022-08-18 | Bearing cage and manufacturing method therefor |
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JP3652396B2 (en) * | 1995-01-27 | 2005-05-25 | 光洋精工株式会社 | Manufacturing method of cage made of synthetic resin |
JP3666536B2 (en) | 1997-05-19 | 2005-06-29 | 光洋精工株式会社 | Manufacturing method of cage made of synthetic resin |
JP3731647B2 (en) * | 2001-04-04 | 2006-01-05 | 日本精工株式会社 | Plastic seal injection molding method |
US7559555B2 (en) * | 2003-05-29 | 2009-07-14 | Ntn Corporation | Resin seal ring and manufacturing method |
JP5428839B2 (en) * | 2009-04-17 | 2014-02-26 | 日本精工株式会社 | Synthetic resin cage, manufacturing method thereof, and rolling bearing |
JP5636868B2 (en) | 2010-10-20 | 2014-12-10 | 日本精工株式会社 | Synthetic resin cage |
JP2012092862A (en) | 2010-10-25 | 2012-05-17 | Nsk Ltd | Plastic retainer, method of manufacturing the same, and rolling bearing |
JP2012219917A (en) | 2011-04-08 | 2012-11-12 | Nsk Ltd | Resin member, bearing retainer, and method for manufacturing the same |
JP5768486B2 (en) | 2011-05-12 | 2015-08-26 | 日本精工株式会社 | Resin cage for bearing and method for manufacturing the same |
JP2013029164A (en) * | 2011-07-28 | 2013-02-07 | Nsk Ltd | Resin-made retainer for bearing and manufacturing method therefor, as well as roller bearing |
JP5244256B1 (en) | 2012-12-25 | 2013-07-24 | 日進工業株式会社 | Injection molding method and injection molded product |
JP2015197210A (en) | 2014-04-03 | 2015-11-09 | 日本精工株式会社 | Bearing cage and its manufacturing method |
JP2015224664A (en) | 2014-05-26 | 2015-12-14 | 日本精工株式会社 | Manufacturing method of cage for rolling bearing |
JP6299529B2 (en) | 2014-08-29 | 2018-03-28 | 日本精工株式会社 | Bearing cage and manufacturing method thereof |
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2016
- 2016-02-19 EP EP16890578.4A patent/EP3418024B1/en active Active
- 2016-02-19 CN CN201680082096.8A patent/CN108698282A/en active Pending
- 2016-02-19 US US16/076,899 patent/US11465319B2/en active Active
- 2016-02-19 JP JP2017567925A patent/JP6471813B2/en active Active
- 2016-02-19 WO PCT/JP2016/054929 patent/WO2017141437A1/en active Application Filing
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2022
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Also Published As
Publication number | Publication date |
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EP3418024B1 (en) | 2020-02-05 |
US11465319B2 (en) | 2022-10-11 |
JP6471813B2 (en) | 2019-02-20 |
EP3418024A4 (en) | 2019-03-06 |
JPWO2017141437A1 (en) | 2018-11-08 |
CN108698282A (en) | 2018-10-23 |
EP3418024A1 (en) | 2018-12-26 |
WO2017141437A1 (en) | 2017-08-24 |
US20190061212A1 (en) | 2019-02-28 |
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