7000 Series Single-Row 29° Angular Contact Ball Bearings 121 MRC 7000 Series bearings are single-row 29° angular contact ball bearings having one heavy race shoulder and one counterbored race shoulder on the outer ring. Because of this construction, it is possible to incorporate a greater number of balls than in the deep groove nonfilling notch bearing. The combination of maximum ball complement and the angular contact feature reduces the specific ball loading under thrust load, resulting in moderate to high thrust load carrying capacity. MRC 7000 Series angular contact ball bearings should be used in applications in which the thrust load is heavy and beyond the capacity of single-row types; for example, for a heavy thrust load in one direction, or a heavy thrust load in one direction combined with a radial load. Cage Types and Materials For normal usage: heavy stock, two-piece steel formed pockets, with turned-over fingers or riveted together. For severe vibration, very high speeds, or high operating temperatures: one-piece, inner ring land- guided, machined construction of suitable material (phenolic/bakelite composition, machined brass, or special material). Size 7100/D Extra Large—Single Bearing and Duplex Set 122 7100KR Extra Light—Single Bearing 123 7100KRD Extra Light—Duplex Set 124 7200 Light—Single Bearing 125 7200D Light—Duplex Set 126 7300 Medium—Single Bearing 127 7300D Medium—Duplex Set 128 7400/D Heavy—Single Bearing and Duplex Set 129 Series Page 7000 Equivalent Load and Life 130 7000 Minimum Load Calculation 130 7000 Life Calculation Examples 131 7000D Equivalent Load and Life 132 7000D Life Calculation Examples 133
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7000 Series Single-Row 29° Angular Contact Ball …Angular Contact Ball Bearings 121 MRC 7000 Series bearings are single-row 29 angular contact ball bearings having one heavy race
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7000 Series Single-Row 29°
Angular Contact Ball Bearings
121
MRC 7000 Series bearings are single-row 29°angular contact ball bearings having one heavy raceshoulder and one counterbored race shoulder on the outer ring. Because of this construction, it ispossible to incorporate a greater number of balls than in the deep groove nonfilling notch bearing. The combination of maximum ball complement and the angular contact feature reduces the specific ballloading under thrust load, resulting in moderate to high thrust load carrying capacity.
MRC 7000 Series angular contact ball bearings shouldbe used in applications in which the thrust load isheavy and beyond the capacity of single-row types; for example, for a heavy thrust load in one direction, or a heavy thrust load in one direction combined with a radial load.
Cage Types and Materials
For normal usage: heavy stock, two-piece steel formed pockets, with turned-over fingers or rivetedtogether.
For severe vibration, very high speeds, or highoperating temperatures: one-piece, inner ring land-guided, machined construction of suitable material(phenolic/bakelite composition, machined brass, orspecial material).
Size
7100/D Extra Large—Single Bearing and Duplex Set 122
7100KR Extra Light—Single Bearing 123
7100KRD Extra Light—Duplex Set 124
7200 Light—Single Bearing 125
7200D Light—Duplex Set 126
7300 Medium—Single Bearing 127
7300D Medium—Duplex Set 128
7400/D Heavy—Single Bearing and Duplex Set 129
Series Page
7000 Equivalent Load and Life 130
7000 Minimum Load Calculation 130
7000 Life Calculation Examples 131
7000D Equivalent Load and Life 132
7000D Life Calculation Examples 133
MRC Bearing Services
7100 and 7100-D
Extra Large Series
122
7100 Series bearings are similar to the 7100-KRSeries but have a larger O.D. and narrower width;and are used for one-directional thrust loads orcombined radial and thrust loads where the thrustload is predominant.
“D” indicates a duplex ground half pair matched with an identical half pair and isfollowed by an additional suffix letter to describe the type of duplex. See pages 234 and 235 for suffix description.
Caution: Single bearings are not to be used whereonly radial loads are present. For two-directionthrust loads, use duplex bearings.
Values for -D bearings are for back-to-back (DB) or face-to-face (DF) mountingarrangements.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.32 and C0 by 2.94 (single) and C by 0.81 and C0 by 1.47 (duplex).3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice.For a more complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.5) Typically non-stocked sizes, please check availability before designing into equipment.
Note: ABEC-1 & 3 stocked as half-pairs, where available.
7100-D
7100-KR Extra Light Series
(Single Bearings)
123
This series is available in bore sizes ranging from 10mm to 320 mm. One-piece machined nonmetallic orsolid bronze cages are considered standard for thisseries. These bearings are appropriate for use withmoderate one-directional thrust loads, or combinedradial and thrust loads where the thrust load is predominant.
Caution: Single bearings are not to be used whereonly radial loads are present. For two-directionthrust loads, use duplex bearings.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.32 and C0 by 2.94.3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
MRC Bearing Services
7100-KRD Extra Light Series
Duplex
124
“D” indicates a duplex ground half pair matched with an identical half pair and is fol-lowed by an additional suffix letter to describe the type of duplex. See pages 234 and235 for suffix description.
Use these values for back-to-back (DB) or face-to-face (DF) mounting arrangements.
Note: ABEC - 1 & 3 stocked as half-pairs, where available.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 0.81 and Co by 1.47.3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
7200 Light Series
(Single Bearings)
125
The 7200 Series contains single-row angular contact ballbearings with a counterbored outer ring. Bore sizesrange from 10 mm to 320 mm; and most of thesebearings are available with a two-piece pressed steelcage, or a one-piece nonmetallic or solid bronze cage.7000 Series bearings are designed with an initial contact angle of 29°, although some small sizes mayhave a lesser angle. 7200 Series bearings can be usedwith moderate to heavy one-directional thrust loads, orcombined radial and thrust loads where the thrust loadis predominant. Caution: Single bearings are not to be used whereonly radial loads are present. For two-directionthrust loads, use duplex bearings.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.32 and C0 by 2.94.3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
MRC Bearing Services
7200-D Light Series
Duplex
126
“D” indicates a duplex ground half pair matched withan identical half pair and is followed by an additionalsuffix letter to describe the type of duplex. See pages234 and 235 for suffix description.
For duplex sets of 7000 and 9000 series bearings see page 237.
Use these values for back-to-back (DB) or face-to-face (DF) mounting arrangements.
Note: ABEC-1 & 3 stocked as half-pairs, where available.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 0.81 and Co by 1.47.3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
7300 Medium Series
(Single Bearings)
127
7300 series bearings have the same ring and ballcage construction as the 7200 Series but are heaviersectioned bearings with a ball complement capableof handling heavier loads. 7300 Series are listed withbore sizes from 10 mm to 280 mm. For two directionalthrust loads, use duplex bearings.
Caution: Single bearings are not to be used whereonly radial loads are present. For two-directionthrust loads, use duplex bearings.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.32 and C0 by 2.94.3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
MRC Bearing Services
7300-D Medium Series
Duplex
128
“D” indicates a duplex ground half pair matched with an identical half pair and is followed by an additionalsuffix letter to describe the type of duplex. See pages234 and 235 for suffix description.
For duplex sets of 7000 and 9000 series bearings see page 237.
Use these values for back-to-back (DB) or face-to-face (DF) mounting arrangements.
Note: ABEC-1 & 3 stocked as half-pairs where available.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 0.81 and C0 by 1.47.3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
7400 and 7400-D
Heavy Series
129
7400 Series bearings are similar to the 7200 and 7300Series but are heavier sectioned and are used forheavy one-directional thrust loads or combined radialand thrust loads where the thrust load is predominant.
“D” indicates a duplex ground half pair matched with an identical half pair and is followedby an additional suffix letter to describe the type of duplex. See pages 234 and 235 for suffix description.
Caution: Single bearings are not to be used where only radial loads are present. For two-direction thrust loads, use duplex bearings.
Values for -D bearings are for back-to-back or face-to-face (DF) mounting arrangements.
Note: ABEC 1 & 3 stocked as half-pairs where available.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.32 and Co by 2.94 (single) and C by 0.81 and C0 by 1.47 (duplex).3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
7400-D
MRC Bearing Services
130
Dynamic and static equivalent radial load and life rating
Dynamic equivalent radial load
P = FR when FA/FR ≤ 0.80orP = 0.39 FR + 0.76 FA when FA/FR > 0.80
Satisfactory operation of angular contactball bearings requires sufficient tractionforces between the balls and races tominimize damage caused by sliding orskidding. This is particularly important athigh speeds where the inertia forces ofthe balls and cage and the viscous dragin the lubricant can have a detrimentalinfluence on the rolling conditions.
The minimum required thrust load can be determined from the followingformula.
FA = A Newtons
or
FA = 0.2248 A Pounds
Where, FA = Minimum thrust load A = Bearing design factor listed
in the following tables n = Speed in RPM
Note: For Duplex Bearings mounted in tandem, multiply the
single-bearing thrust value by the number of bearings in tandem.
n1000( )
2
n1000( )
2
Minimum Thrust Load For
Angular Contact Ball Bearings
131
7000 Series
29° Angular Contact Ball Bearings
Single Bearing
Dynamic equivalent radial load and life calculation examples
Bearing size: 7309
Speed: 2000 RPM
Basic dynamic radial load rating (C) = 11800
Case 1
Radial load (FR) = 1750
Thrust load (FA) = 1310
Equivalent load (P) = FR or 0.39 FR + 0.76 FA
FA/FR = 1310/1750 = 0.75
Since FA/FR < 0.80, P = FR = 1750
Life (L10) = = = 307 × 106 Rev.
or
Life (L10h) = =
= 2555 Hrs
( )C
P
3
( )C
P10
60n
3610
60 × 2000
6
( )11800
1750
3
( )11800
1750
3
Case 2
Radial load (FR) = 1750
Thrust load (FA) = 2100
Equivalent load (P) = FR or 0.39 FR + 0.76 FA
FA/FR = 2100/1750 = 1.20
Since FA/FR > 0.80, P = 0.39 × 1750 + 0.76 × 2100 = 2279
Life (L10) = = = 139 × 106 Rev.
or
Life (L10h) = =
= 1157 Hrs
( )C
P
3
( )C
P10
60n
3610
60 × 2000
6
( )11800
2279
3
( )11800
2279
3
Case 3
Thrust load (FA) = 2100
Equivalent load (P) = 0.39 FR + 0.76 FA
FA/FR = 2100/0 = ∞
Since FA/FR > 0.80, P = 0.76 × 2100 = 1596
Life (L10) = = = 404 × 106 Rev.
or
Life (L10h) = =
= 3368 Hrs
( )C
P
3
( )C
P10
60n
3610
60 × 2000
6
( )11800
1596
3
( )11800
1596
3
MRC Bearing Services
132
7000-D Series
29° Angular Contact Ball Bearings
Duplex
Dynamic and static equivalent radial load and life rating
Dynamic equivalent radial loadDB or DF pairP = 1.0 FR + 0.78 FA when ≤ 0.80
Dynamic equivalent radial load and life calculation examples
Bearing size: 7309DU (DB or DF pair)
Speed: 2000 RPM
Duplex pair basic dynamic radial load
rating (C) = 19200
Bearing size: 7309DT
3 bearings in tandem
Speed: 2000 RPM
Single-row basic dynamic radial load
rating (C) = 11800
Case 1
Radial load (FR) = 1750
Thrust load (FA) = 1310
FA/FR = 1310/1750 = 0.75
Since FA/FR < 0.80, equivalent load
(P) = 1.0 FR + 0.78 FA
= 1.0 × 1750 + 0.78 × 1310 = 2772
Case 2
Radial load (FR) = 1750
Thrust load (FA) = 2100
FA/FR = 2100/1750 = 1.20
Since FA/FR > 0.80, equivalent load
(P) = 0.63 FR + 1.24 FA
= 0.63 × 1750 + 1.24 × 2100 = 3707
Case 1
Thrust load (FA) = 4200
FA/FR = 4200/0 = ∞
Since FA/FR > 0.80, equivalent load
(P) = 0.39 FR + 0.76 FA = 0.76 × 4200 = 3192
Load rating = (i)0.7 × 11800
= (3)0.7 × 11800 = 25460
Case 2
Radial load (FR) = 3500
Thrust load (FA) = 4200
FA/FR = 4200/3500 = 1.20
Since FA/FR > 0.80, equivalent load
(P) = 0.39 FR + 0.76 FA
= 0.39 × 3500 + 0.76 × 4200 = 4557
Load rating = (i)0.7 × 11800
= (3)0.7 × 11800 = 25460
Life (L10) = = = 332 × 106 Rev.
or
Life (L10h) = =
= 2769 Hrs
( )C
P
3
( )C
P10
60n
3610
60 × 2000
6
( )19200
2772
3
( )19200
2772
3
Life (L10) = = = 139 × 106 Rev.
or
Life (L10h) = =
= 1158 Hrs
( )C
P
3
( )C
P10
60n
3610
60 × 2000
6
( )19200
3707
3
( )19200
3707
3
Life (L10) = = = 507 × 106 Rev.
or
Life (L10h) = =
= 4229 Hrs
( )C
P
3
( )C
P10
60n
3610
60 × 2000
6
( )25460
3192
3
( )25460
3192
3
Life (L10) = = = 174 × 106 Rev.
or
Life (L10h) = =
= 1453 Hrs
( )C
P
3
( )C
P10
60n
3610
60 × 2000
6
( )25460
4557
3
( )25460
4557
3
Case 3
Thrust load (FA) = 2100
FA/FR = 2100/0 = ∞
Since FA/FR > 0.80, equivalent load
(P) = 0.63 FR + 1.24 FA = 1.24 × 2100 = 2604
Life (L10) = = = 401 × 106 Rev.
or
Life (L10h) = =
= 3340 Hrs
( )C
P
3
( )C
P10
60n
3610
60 × 2000
6
( )19200
2604
3
( )19200
2604
3
134
Size
7200P Light—Single Bearing 136
7200PD Light—Duplex Set 137
7300P Medium—Single Bearing 138
7300PD Medium—Duplex Set 139
7400P/PD Heavy—Single Bearing and Duplex Set 140
Series Page
7000P Equivalent Load and Life 142
7000P Minimum Load Calculation 142
7000P Life Calculation Examples 143
7000PD Equivalent Load and Life 144
7000PD Life Calculation Examples 145
7000-P Series Single-Row 40°
Angular Contact Ball Bearings
135
MRC 7000-P Series bearings are similar in design to7000 Series bearings, but the 7000-P Series bearingshave features that give them a greatly increased thrust capacity. They are especially recommended for those applications where maximum thrust capacityis required.
This heavy-duty angular contact ball bearing series isdesigned with an optimum ball complement and racegroove depth, and have a 40° contact angle. 7000-P
bearings are restricted to applications involvingprimarily thrust loads. They should not be usedwhere the bearing will be subjected to radial loadexclusively, or combined radial and thrust load where the radial load is predominant.
Cage Types and Materials
Furnished in one-piece, inner-ring land-guided,machined brass, phenolic/bakelite composition or special material.
MRC Bearing Services
7200-P Light Series
(Single Bearings)
136
7200-P Light Series bearings are available in bore sizes ranging from 10 mm to 200 mm. They are usedwith heavy one-directional thrust loads, or combinedradial and thrust loads where the thrust load ispredominant.
Caution: Single bearings are not to be used whereonly radial loads are present. For two-directionthrust loads, use duplex bearings.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.75 and C0 by 3.85.3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
7200-PD Light Series
Duplex
137
“D” indicates a duplex ground half pair matched with an identical half pair and is followed by an additional suffix letter to describe the type of duplex. See pages 234 and 235 for suffix description.
For duplex sets of 7000 and 9000 series bearings see page 237.
Use these values for back-to-back (DB) or face-to-face (DF) mounting arrangements.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.08 and C0 by 1.93.3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
Note: ABEC - 1 & 3 stocked as half-pairs, where available.
rb
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MRC Bearing Services
7300-P Medium Series
(Single Bearings)
138
7300-P Medium Series bearings are available in boresizes from 10 mm to 200 mm. They can accommodate very heavy one-directional thrustloads, or combined radial and thrust loads where thethrust load is predominant.
Caution: Single bearings are not to be used where only radial loads are present. For two-direction thrust loads, use duplex bearings.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.75 and C0 by 3.85.3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
7300-PD Medium Series
Duplex
139
“D” indicates a duplex ground half pair matched with an identical half pair and isfollowed by an additional suffix letter to describe the type of duplex. See pages 234and 235 for suffix description.
For duplex sets of 7000 and 9000 series bearings see page 237.
Use these values for back-to-back (DB) or face-to-face (DF) mounting arrangements.
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.08 and C0 by 1.93.3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 274.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
Note: ABEC-1 & 3 stocked as half-pairs, where available.
rb
ra
MRC Bearing Services
7400-P and 7400-PD
Heavy Series
140
7400-P Series bearings are similar to the 7200-P and 7300-P Series, but are heavier sectioned, and are used for very heavy thrust loads or combined radial and thrustloads where the thrust load is predominant.
“D” indicates a duplex ground half pair matched with an identical half pair and is followed byan additional suffix letter to describe the type of duplex. See pages 234 and 235 for suffixdescription.
For duplex sets of 7000 and 9000 series bearings see page 237.
Caution: Single bearings are not to be used whereonly radial loads are present. For two-direction thrustloads, use duplex bearings.
Values for -D bearings are for back-to-back (DB) or face-to-face (DF) mounting arrangements.
Note: ABEC 1 & 3 stocked as half-pairs where available.
7400-PD
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.75 and C0 by 3.85 (single) and C by 1.08 and C0 by 1.93 (duplex).3) Listed values are for machined bronze cage, ABEC-1.
For phenolic composition cage, multiply by 1.33 for both grease and oil. For phenolic composition cage, ABEC-5 or 7, multiply by 1.86 for both grease and oil. For pressedsteel cage, ABEC-1, multiply by 0.67 for grease and 0.80 for oil. The speed rating adjustment factors have been determined through historical application and practice. For amore complete explanation, see page 276.
4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
141
MRC Bearing Services
142
Dynamic and static equivalent radial load and life rating
Satisfactory operation of angular contact ball bearingsrequires sufficient traction forces between the balls and racesto minimize damage caused by sliding or skidding. This isparticularly important at high speeds where the inertia forcesof the balls and cage and the viscous drag in the lubricantcan have a detrimental influence on the rolling conditions.
The minimum required thrust load can be determined fromthe following formula.
FA = A Newtons
or
FA = 0.2248 A Pounds
Where, FA = Minimum thrust load A = Bearing design factor listed in the following tables n = Speed in RPM
Note: For Duplex Bearings mounted in tandem, multiply the single-bearing thrust value by the
number of bearings in tandem.
n1000( )
2
n1000( )
2
Minimum Thrust Load For Angular Contact
Ball Bearings
143
Dynamic equivalent radial load and life calculation examples
MRC angular contact ball bearings with a PJ suffix have one heavy race shoulder and one counterbored raceshoulder on the outer ring; opposing one heavy raceshoulder and one counterbored race shoulder on theinner ring. Because of this construction, it is possible for this bearing to incorporate a greater number of balls than a deep groove, nonfilling notch bearing. The combination of maximum ball complement,optimum race groove depth, and the 40° contact angle results in high thrust load carrying capacity.
MRC 7000-PJ Series bearings are particularly suitablefor positions where the thrust is always present in onedirection. They should not be used where the bearing is subjected to radial load only; or combined radial and thrust load where the radial load is predominant. When heavy thrust must be taken in both directions, the PJD series angular contact ball bearings may bemounted in a back-to-back or face-to-face duplexarrangement with another angular contact bearing.
MRC 7000-PJ Series bearings are available with eitherpressed brass or machined brass, ball centered cages.The low shoulder diameters on the nonthrust sides of the inner and outer rings, combined with largeclearances between the land diameters and the cage,allow for large quantities of oil to flow through thesebearings. The increased oil flow reduces operatingtemperature and theoretically increases bearing life.
ABEC-3 bore tolerances reduce the range ofinterference fits between the shaft and bearing bore.These tighter tolerances result in closer control ofpreload and minimize the risk of thermal runaway.
Size
7200-PJ Light—Single Bearing 148
7200-PJD Light—Duplex Set 148
7300-PJ Medium—Single Bearing 149
7300-PJD Medium—Duplex Set 149
7400-PJ Heavy—Single Bearing 150
7400-PJD Heavy—Duplex Set 150
Series Page
7000-PJ Equivalent Load and Life 152
7000-PJ Minimum Load Calculations 152
7000-PJ Life Calculation Examples 153
7000-PJD Equivalent Load and Life 154
7000-PJD Life Calculation Examples 154
MRC Bearing Services
7200-PJ Light Series and
7200-PJD Light Series, Duplex
148
7200-PJ and -PJD Series bearings are used for heavyone-directional thrust loads, or combined radial andthrust loads where the thrust load is predominant.
“D” indicates a duplex ground half pair matched with an identical half pair and is followed by an additional suffix letter to describe the type of duplex. See pages 234and 235 for suffix description.
Caution: Single bearings are not to be used whereonly radial loads are present. For two-directionthrust loads, use duplex bearings.
Values for -PJD bearings are for back-to-back (DB) or face-to-face (DF) mounting arrangements.
Note: ABEC 1 & 3 stocked as half-pairs, where available.
7200-PJD
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.75 and C0 by 3.85 (single) and C by 1.08 and C0 by 1.93 (duplex).3) Listed values are for pressed brass and steel or polyamide cage.
The values have been determined through historical application and practice. For a more complete explanation, see page 274.4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
7300-PJ Medium Series and 7300-PJD
Medium Series, Duplex
149
7300-PJ and -PJD Series bearings are used for veryheavy one-directional thrust loads, or combined radialand thrust loads where the thrust load is predominant.
“D” indicates a duplex ground half pair matched with an identical half pair and is followedby an additional suffix letter to describe the type of duplex. See pages 234 and 235 for suf-fix description.
Caution: Single bearings are not to be used whereonly radial loads are present. For two-directionthrust loads, use duplex bearings.
Values for -PJD bearings are for back-to-back (DB) or face-to-face (DF) mounting arrange-ments.
Note: ABEC 1 & 3 stocked as half-pairs, where available.
7300-PJD
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.75 and C0 by 3.85 (single) and C by 1.08 and C0 by 1.93 (duplex).3) Listed values are for pressed brass and steel or polyamide cage.
The values have been determined through historical application and practice. For a more complete explanation, see page 274.4) Rating for one million revolutions or 500 hours at 33¹|₃ RPM.
MRC Bearing Services
7400-PJ Heavy Series and
7400-PJD Heavy Series, Duplex
150
7400-PJ and -PJD Series bearings are similar to the 7200-PJ and 7300-PJ Series, but are heavier sectioned; andare used for very heavy one-directional thrust loads, orcombined radial and thrust loads where the thrust load ispredominant.
“D” indicates a duplex ground half pair matched with an identical half pair and is followed by an additional suffix letter to describe the type of duplex. See pages 234 nad 235 for suffix description.
Caution: Single bearings are not to be used where onlyradial loads are present. For two-direction thrust loads,use duplex bearings.
Values for -D bearings are for back-to-back (DB) or face-to-face (DF) mounting arrangements.
Note: ABEC 1 & 3 stocked as half-pairs, where available.
7400-PJD
1) Fillet radius indicates maximum fillet radius on shaft or in housing which bearing corner will clear.2) For thrust rating multiply C by 1.75 and C0 by 3.85 (single) and C by 1.08 and C0 by 1.93 (duplex).3) Listed values are for machined bronze cage, ABEC-1.
The values have been determined through historical application and practice. For a more complete explanation, see page 274.4) Rating for one million revolutions or 500 hours at 33C|z RPM.
151
MRC Bearing Services
152
Dynamic and static equivalent radial load and life rating
Satisfactory operation of angular contact ball bearingsrequires sufficient traction forces between the balls andraces to minimize damage caused by sliding or skidding.This is particularly important at high speeds where theinertia forces of the balls and cage and the viscous dragin the lubricant can have a detrimental influence on therolling conditions.
The minimum required thrust load can be determinedfrom the following formula.
FA = A Newtons
OR
FA = 0.2248 A Pounds
Where, FA = Minimum thrust load A = Bearing design factor
listed in the following tables n = Speed in RPM
Note: For Duplex Bearings mounted in tandem, multiply the single-bearing thrust value bythe number of bearings in tandem.
n1000( )
2
n1000( )
2
7000-PJ Series
40° Angular Contact Ball Bearings
Single Bearing
153
Dynamic equivalent radial load and life calculation examples