JP4910938B2 - Double row ball bearing - Google Patents

Description

The present invention relates to an improvement of the double row ball bearing used in a state incorporated in the engine starting device of an idling stop vehicle.

  In recent years, for the purpose of reducing carbon dioxide emission, a so-called idling stop vehicle in which a traveling engine is also stopped as the vehicle is stopped is becoming popular. In the case of an idling stop vehicle, at the time of start, the driver takes his foot off the brake pedal and depresses the accelerator pedal (in the case of an automatic transmission), or from depressing the clutch pedal to depressing the accelerator pedal. In the case of a manual transmission vehicle, it is necessary to start the engine. For this reason, the engine starter for an idling stop vehicle needs to have a shorter time required for starting the engine than the engine starter for a normal vehicle.

  Therefore, conventionally, as described in Patent Document 1, for example, there has been an engine starter that always keeps the pinion gear that is rotationally driven by a starter motor and the ring gear that rotationally drives the crankshaft of the engine kept engaged. It has been. In the case of this engine starter, a one-way clutch is provided between the crankshaft and the ring gear, and an inner ring for clutch that is connected to the ring gear and constitutes the one-way clutch is disposed around the crankshaft. Moreover, it is rotatably supported by a double row ball bearing which is an object of the present invention. The clutch outer ring of the one-way clutch is coupled to the crankshaft. This one-way clutch is connected when the engine is started, and is disconnected after the engine is started.

  FIGS. 7 to 8 show a double-row angular ball bearing described in Non-Patent Document 1 as an example of the structure of a double-row ball bearing that can be used in an engine starter for an idling stop vehicle as described above. Show. In the double row ball bearing 1, a plurality of balls 4, 4 and a pair of cages 5, 5 are arranged between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the inner ring 3 which are arranged concentrically with each other. It consists of Each of these balls 4, 4 is between a double row outer ring raceway 6, 6 formed on the inner peripheral surface of the outer ring 2 and a double row inner ring raceway 7, 7 formed on the outer peripheral surface of the inner ring 3, A plurality of rolls are provided for each of the two rows. Furthermore, both the cages 5 and 5 hold the balls 4 and 4 so as to roll freely for both the rows. In order to incorporate a plurality of balls 4, 4 into the annular gap between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the inner ring 3, as described in Patent Document 2, as shown in FIG. In addition, after the outer ring 2 and the inner ring 3 are eccentric, the necessary number of balls 4 and 4 are assembled between the outer ring raceway 6 and the inner ring raceway 7 so as to stick to each other. 4 and 4 are equally distributed in the circumferential direction.

  The above-mentioned double row ball bearing 1 shown in FIGS. 7 to 8 is incorporated in an engine starter for an idling stop vehicle, for example, and supports the inner ring of the one-way clutch rotatably around the crankshaft. From there is no problem. However, there is a point to be improved in terms of improving the degree of freedom of installation in a limited space while ensuring the required performance. That is, in the case of the engine starting device, the inner ring of the one-way clutch needs to be supported so that the central axis of the inner ring does not tilt with respect to the central axis of the crankshaft (not a single-row ball bearing). Although the double row ball bearing 1 as shown in FIG. 8 is used, the load (radial load and thrust load) applied to the double row ball bearing 1 during use is not so large. Therefore, even if the required durability is taken into consideration, the cross-sectional areas of the outer ring 2 and the inner ring 3 can be reduced compared to the double row ball bearing used for general purposes. However, the structure of the double row ball bearing in which the dimensions of each part are appropriately regulated in consideration of such points has not been known in the past.

JP 2007-32492 A JP-A-7-113420 Catalog of NSK Ltd., “Rolling bearing”, No. 1102b, 2005, A11, B66-67

In view of the circumstances as described above, the present invention provides the required durability when used in applications where the applied load is limited, such as the rotation support portion of the engine starter for idling stop vehicles described above. The invention was invented to realize a structure of a double-row ball bearing capable of improving the degree of freedom of installation in a limited space.

The double-row ball bearing of the present invention is an inner ring having a double-row outer ring raceway on the inner peripheral surface and a double-row inner ring raceway on the outer peripheral surface in the same manner as the previously known double-row ball bearings. A plurality of balls which are provided so as to be able to roll plurally in both rows between the outer ring raceways and the inner ring raceways, and a pair of cages for holding the balls freely. And is incorporated in an engine starter for an idling stop vehicle, and rotatably supports an inner ring for a clutch constituting a one-way clutch around a crankshaft.
In particular, in the double row ball bearing of the present invention, the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring are formed by this heat treatment by scraping the surfaces by machining applied after the heat treatment. The oxide film has been removed.
In addition, the pair of cages described above is constructed in a multiple gate system in which molten resin is fed into a cavity for injection molding from a plurality of locations in the circumferential direction, or a disc gate system in which the entire circumference is on the entire circumference. A synthetic resin crown-shaped cage having a roundness of 0.30 mm or less.
The diameter of each ball is Da, the diameter of the pitch circle of each ball is PCD, the number of balls incorporated in each row is Z, and the axial distance between the centers of the balls in both rows is P. and, the width in the axial direction of the double-row ball bearing and B, and the thickness in the radial direction of the outer ring and T _2, the thickness in the radial direction of the inner ring and T _3, in the radial direction of the both retainers the thickness of the T _5, the thickness in the radial direction of the outer ring raceway portion of the outer ring and t _2, the thickness in the radial direction of the inner ring raceway portion of the inner ring when the _{t 3, (Z · Da)} / (Π · PCD) = 0.20 to 0.35, Da <P <1.25 Da, B = (2.8 to 3.2) Da, and PCD = (17 to 24) Da, _and, PCD / T 2 = _{25~35, and,} PCD / T 3 = _25~35, and, PCD T ₅ = 40 to 50, _and, T 2> _{T 3,} and _satisfies the relation of _t 2> t _3.

According to the double-row ball bearing of the present invention configured as described above, when used in applications where the applied load is limited, the required durability is ensured and the installation in a limited space is free. The degree can be improved. That is, in the case of the present invention, the pitch circle is made larger than the diameter of each ball, and the radial thicknesses of the outer ring and the inner ring are made smaller. Even when the inner ring for clutch is increased, the radial dimension of the cross section (the cross section height of the double row ball bearing = the radial distance between the outer peripheral surface of the outer ring and the inner peripheral surface of the inner ring) can be kept small. Although the load capacity of the double row ball bearing is reduced, the rotation support portion of the engine starter for the idling stop vehicle described above can sufficiently secure the required durability because the applied load is limited .

In the present invention, since the width in the axial direction of the double row ball bearing is 2.8 to 3.2 times the diameter of each ball, the axial dimension of the cross section of the double row ball bearing can be suppressed. Thus, the degree of freedom of installation in a space having a narrow axial dimension is also improved.
Further, the thickness in the radial direction of the two holding devices, suppresses the _PCD / T 5 = _40~50, because they kept below 0.30mm the roundness of both retainers, and out of both retainers The cross-sectional height of the double row ball bearing can be suppressed while preventing interference (excessive rubbing) between both the peripheral surfaces and the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring.
Moreover, since both the cages are made of a synthetic resin crown type cage , the above structure can be realized with a high yield (at a low cost).

Furthermore, in the case of the present invention, the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring are scraped off by machining performed after heat treatment, and an excessively hard oxidation formed on both peripheral surfaces along with the heat treatment. The film is removed. For this reason , it is possible to prevent the rolling surfaces of these balls from being damaged during the assembling work of the balls. Further, it is possible to prevent hard oxide film fragments, which have fallen off from the two peripheral surfaces during the assembling operation, from entering the lubricant and damaging the portion lubricated by the lubricant.

  1 to 6, an example of the embodiment of the present invention will be described. The double row ball bearing 1a of the present example includes a plurality of ball bearings between the inner peripheral surface of the outer ring 2a and the outer peripheral surface of the inner ring 3a that are arranged concentrically with each other, as in the conventional double row ball bearing described above. The balls 4 and 4 and a pair of cages 5a and 5a are arranged. Each of these balls 4, 4 is between a double row outer ring raceway 6, 6 formed on the inner peripheral surface of the outer ring 2a and a double row inner ring raceway 7, 7 formed on the outer peripheral surface of the inner ring 3a. A plurality of rolls are provided for each of the two rows. Further, both the cages 5a and 5a hold the balls 4 and 4 so as to roll freely for the both rows. Note that locking grooves 17 and 17 are formed over the entire circumference of the outer circumferential surface of the outer ring 2a near the both ends in the axial direction. A retaining ring 18 is appropriately latched in both the locking grooves 17 and 17, and other parts such as an inner ring for a one-way clutch are coupled and supported around the outer ring 2a.

Particularly, in the case of double row ball bearing 1a of the present embodiment, the diameter PCD ₄ of the pitch circle of the balls 4, 4, 17-24 times the diameter Da of the balls 4,4 _{PCD 4 = (17 To 24) Da}, the diameter of the double row ball bearing 1a is made relatively large compared to the diameter Da of each of the balls 4 and 4. In other words, in the case of the double row ball bearing 1a of this example, the diameter of each of the balls 4 and 4 is larger than that of the conventional double row ball bearing as described in Non-Patent Document 1 described above. Da is made smaller than the diameter PCD _{4 of the} pitch circle. Therefore, in the case of this example, as will be described later, in combination with the suppression of the thicknesses T ₂ and T ₃ in the radial direction of the outer ring 2a and the inner ring 3a, the cross-sectional height H of the double row ball bearing 1a is set. This reduces the degree of freedom of installation in a space with limited radial dimensions. Further, the number of balls 4 and 4 incorporated in both rows is relatively small. In other words, conventionally used ball bearings (both single row and double row) have balls arranged on half or more than half of the pitch circle. Specifically, assuming that the number of balls arranged on the pitch circle is Z, (Z · Da) / (π · PCD ₄ ) ≧ 0.5. On the other hand, in the case of the double-row ball bearing 1a of this example, (Z · Da) / (π · PCD ₄ ) = 0.20 to 0.35, and the number of balls arranged on the pitch circle. Z is kept low.

  The reason why the number Z of the balls 4 and 4 is thus reduced is to keep the dynamic torque of the double row ball bearing 1a low. That is, it is considered that the double row ball bearing 1a of this example is used in a state where it is incorporated in an engine starter of an idling stop vehicle as described in Patent Document 1 described above. In such a use state, the outer ring 2a and the inner ring 3a constituting the double row ball bearing 1a rotate relative to each other as long as the engine rotates. On the other hand, the reason for performing idling stop is to reduce the fuel consumption of the engine, and it is necessary to suppress the existence of the double row ball bearing 1a from deteriorating the fuel consumption rate as much as possible. Therefore, in the case of this example, the number Z of the balls 4 and 4 is reduced to keep the dynamic torque of the double row ball bearing 1a low.

  Even if the number Z of these balls 4 and 4 is reduced, there is no problem in terms of durability of the double row ball bearing 1a. That is, the load applied to the double row ball bearing 1a is about the reaction force in the radial direction generated at the meshing portion of the ring gear and the pinion constituting the engine starting device, and the time during which the reaction force is applied. Is very short. The load applied to the double-row ball bearing 1a after the engine starts is only a slight radial load such as the weight of the outer ring 2a and the weight of the inner ring for one-way clutch that is fitted and fixed to the outer ring 2a. . For this reason, even if the number Z of each of the balls 4 and 4 is reduced, the surface pressure of the rolling contact portion inside the double row ball bearing 1a can be kept sufficiently low, and the durability of the double row ball bearing 1a can be improved. It can be secured sufficiently (the lifetime is not shortened compared to other components constituting the engine starter).

Further, the thicknesses T ₂ and T ₃ in the radial direction of the outer ring 2a and the inner ring 3a are made smaller (thinner) than in the case of the conventional structure. Specifically, the diameter PCD _{4 of the} pitch circle is 25 to 35 times the thickness T _{2 of} the outer ring 2a and the thickness T ₃ of the inner ring 3a (PCD ₄ / T ₂ = 25 to 35, PCD ₄ / T ₃ = 25 to 35), preferably 27 to 33 times (PCD ₄ / T ₂ = 27 to 33, PCD ₄ / T ₃ = 27 to 33). In other words, the radial thicknesses T ₂ and T ₃ of the outer ring 2 a and the inner ring 3 a are suppressed to 1/24 to 1/17 times the diameter PCD ₄ of the pitch circle. In the case of this example, the thickness T ₃ of the inner ring 3a is made smaller than the thickness T ₂ of the outer ring 2a (T ₂ > T ₃ ). In accordance with this, as compared the thickness t ₂ of the outer ring raceways 6,6 part of the outer ring 2a, reducing the thickness t ₃ of the two inner ring raceway 7, 7 part of the inner ring 3a ( t ₂ > t ₃ ). As described above, since the radial load applied to the double row ball bearing 1a is limited, the durability of the double row ball bearing 1a is maintained even if the thicknesses T ₂ and T ₃ of the outer ring 2a and the inner ring 3a are reduced. Enough to secure.

In the case of the double row ball bearing 1a of this example, the axial distance (inter-row pitch) P (see FIG. 2) between the centers of the balls 4 and 4 in both rows is smaller than that in the conventional structure. is doing. Specifically, the axial distance P is larger than the diameter Da of the balls 4 and 4 and less than 1.25 times the diameter Da of the balls 4 and 4 (Da <P <1.25 Da). Yes. Accordingly, the width B in the axial direction of the double row ball bearing 1a (same as the width in the axial direction of the outer ring 2a and the inner ring 3a) B is made smaller than that in the case of the conventional structure. Specifically, the width B is regulated within the range of 2.8 to 3.2 times the diameter Da of the balls 4 and 4 {B = (2.8 to 3.2) Da}. . It should be noted that the ratio of the radius of curvature r _o , r _i of the cross-sectional shapes of the outer ring raceways 6, 6 and the inner ring raceways 7, 7 to the diameter Da of the balls 4, 4 is 0.52 to 0.55. _{{r o = (0.52~0.55) Da} , r i = (0.52~0.55) Da} is set to.

Further, both the cages 5a and 5a are formed as crown-shaped cages as shown in FIG. 3 by injection molding a synthetic resin such as PPS or PEEK. In the case of this example, the diameter PCD _{4 of the} pitch circle is set to 40 to 50 times (PCD ₄ / T ₅ = 40 to 50) the thickness T ₅ in the radial direction of the two cages 5a and 5a. The both retainers 5a, the maximum value of the thickness _{T 5} of 5a _(PCD 4/40) restricts terms of preventing interference with the inner peripheral surface or outer peripheral surface of the inner ring 3a of the outer ring 2a, the minimum value ( PCD _4/50) regulates in terms of securing strength. In any case, the roundness of both the cages 5a and 5a is suppressed to 0.30 mm or less, preferably 0.20 mm or less, so that both the inner and outer peripheral surfaces of these cages 5a and 5a and the outer ring Rubbing with the inner peripheral surface of 2a or the outer peripheral surface of the inner ring 3a is prevented. In order to obtain the two cages 5a and 5a having such excellent roundness, the molding of the cages 5a and 5a is performed by feeding molten resin into a cavity for injection molding in a plurality of circumferential directions. It is preferable to carry out by a multiple gate system performed from a part or a disk gate system performed from almost the entire circumference on the inner circumference side.

  The shape of both the cages 5a and 5a is not particularly limited as long as it is a crown type. However, if both of the cages 5a and 5a have the same shape shown by the chain line rather than the general shape shown by the solid line in FIG. The work of assembling the cages 5a and 5a can be facilitated. That is, the cages 5a and 5a are assembled after the balls 4 and 4 are assembled between the outer ring raceways 6 and 6 and the inner ring raceways 7 and 7, and are further equally distributed in the circumferential direction. The cages 5a and 5a are pressed against the balls 4 and 4 with the openings of the pockets 8 and 8 aligned with the balls 4 and 4, respectively. At this time, as shown in FIG. 3, the elastic claws 9, 9 existing on both sides of the opening of the pocket 8 are elastically deformed in a direction in which the gap between the tip edges is opened. As indicated by the chain line, the base of each of the elastic claws 9, 9 is farther from the tip of each of the elastic claws 9, 9 than the center of the ball to be held in the pocket 8. If the reaching shape is adopted, the elastic claw portions 9 and 9 can be easily elastically deformed during this operation, and the assembling work of the cages 5a and 5a can be facilitated.

  Further, in the case of this example, the inner peripheral surface of the outer ring 2a and the outer peripheral surface of the inner ring 3a are subjected to heat treatment (for quench hardening such as submerged baking performed by dipping in quenching oil after heating). As shown exaggeratedly in FIG. 4, by machining performed after the heat treatment), it is formed on both peripheral surfaces along with this heat treatment by scraping from the state shown by the chain line to the state shown by the solid line. The oxide film is removed. Further, in the case of this example, with the machining, an outer diameter side central bank portion 10 existing between the double row outer ring raceways 6 and 6 at the axially intermediate portion of the inner peripheral surface of the outer ring 2a. The outer diameter side continuous portions 11, 11, which connect both end portions in the axial direction of the portion and the end portions in the axial direction of the outer ring raceways 6, 6, are connected to the end edges of the outer ring raceways 6, 6 and the outer diameter side central bank. It is a curved surface having an arcuate cross section that smoothly continues the inner peripheral surface of the portion 10. Similarly, both axial ends of the inner diameter side central bank portion 12 existing between the double-row inner ring raceways 7 and 7 at the axially intermediate portion of the outer peripheral surface of the inner ring 3a and the inner ring raceways 7 and 7 A curved surface having an arcuate cross section in which the inner diameter side continuous portions 13 and 13 that are continuous with the end portions in the axial direction are smoothly connected to the end edges of the inner ring raceways 7 and 7 and the outer peripheral surface of the inner diameter side central bank portion 12. It is said. The machining is easily performed by polishing each peripheral surface with a rotating grindstone that matches the shape of the inner peripheral surface of the outer ring 2a after completion of the respective busbar shape or the outer peripheral surface shape of the inner ring 3a. Yes. The interval between the chain line and the solid line in FIG. 4 is exaggerated.

When assembling the balls 4, 4 between the outer ring raceways 6, 6 and the inner ring raceways 7, 7 in order to assemble the double row ball bearing 1 a of this example configured as described above, A holding jig 14 as shown in FIG. The holding jig 14 includes a partial arc-shaped base 15 and a pair of holding arms 16 and 16 that are bent in the same direction from both ends of the base 15 and are parallel to each other. The length L 16 of the holding arm portions 16 and ₁₆ is 1.5 times or more of the diameter Da of the balls 4 and 4 {L ₁₆ ≧ 1.5 Da, for example, about twice (L ₁₆ ≈2 Da)}. The distance D _{16 in} the circumferential direction between the holding arm portions 16 and ₁₆ is substantially the same as the product of the number Z of the balls 4 and 4 incorporated in each row and the diameter Da of the balls 4 and 4 ( D ₁₆ ≈Z · Da). Therefore, between the both holding arm portions 16 and 16, Z pieces for each row to be incorporated between the outer ring raceways 6 and 6 and the inner ring raceways 7 and 7 are 2Z in total. In a state where the balls 4 and 4 are arranged in two rows, the balls can be arranged with almost no gap in a state along the pitch circle in the completed double row ball bearing 1a.

  In order to incorporate the balls 4, 4 between the outer ring raceways 6, 6 and the inner raceways 7, 7, first, a pair of restraining arm portions 16, 16 constituting the restraining jig 14 are paired. In between, 2Z balls 4 and 4 are arranged in an arc shape along the pitch circle in two rows, Z in each row. In this case, the balls 4, 4 are prevented from dropping in the radial direction from between the holding arm portions 16, 16 by a cylindrical or partial cylindrical holding plate, if necessary. On the other hand, the outer ring 2a and the inner ring 3a are arranged in an eccentric state as shown in FIG. 9, for example. And in the annular space between the inner peripheral surface of the outer ring 2a and the outer peripheral surface of the inner ring 3a, the 2Z balls 4 and 4 arranged in the arc shape are thickened in the radial direction. And inserted together with the holding jig 14. During this insertion operation, the holding plate is stopped outside the annular space. As shown in FIG. 6 (A), the insertion work is such that the butting surfaces of the balls 4, 4 in different rows are the inner peripheral surface of the outer diameter side central bank portion 10 and the inner diameter side central bank portion 12. This is done until it is located at a portion facing the outer peripheral surface.

Then, from the state shown in FIG. 6A, the outer ring 2a and the inner ring 3a are made concentric with each other. In this process, the outer diameter side central bank portion 10 and the inner diameter side central bank portion 12 enter between the balls 4, 4 of both rows, and exist on both sides of both the bank portions 10, 12. The balls 4, 4 are distributed between the outer ring raceways 6, 6 and the inner ring raceways 7, 7. In the case of this example, as described above, in the state of the double-row ball bearing 1a after completion, the axial distance P between the centers of the balls 4 and 4 in both rows is the diameter of each of the balls 4 and 4. It is larger than Da and less than 1.25 times the diameter Da of each of the balls 4 and 4. For this reason, even if the balls 4 and 4 in both rows are inserted into the annular space from one axial side of the annular space, the diameter direction of the outer ring 2a and the inner ring 3a (vertical direction in FIGS. 1, 2 and 6). With respect to the maximum diameter portions of the balls 4, 4 in both rows, on both sides in the axial direction of the bank portions 10, 12 existing between the outer ring raceways 6, 6 and the inner ring raceways 7, 7 in the double rows, Easy and reliable sorting. And, if the maximum diameter part of the balls 4, 4 in both rows is distributed to both sides in the axial direction of the both bank parts 10, 12, in the process of concentrically arranging the outer ring 2 a and the inner ring 3 a, The two rows of balls 4 and 4 are reliably engaged with the double row outer ring raceways 6 and 6 and the double row inner ring raceways 7 and 7, respectively. For this reason, it is possible to easily perform the work of assembling 2Z balls 4, 4 in total, Z in each row, between the double row outer ring raceways 6, 6 and the double row inner ring raceways 7, 7. Thus, the efficiency of manufacturing the double row ball bearing 1a can be improved, and the manufacturing cost of the double row ball bearing 1a can be reduced. In contrast to the structure of this example, as shown in FIG. 6B, in the case of a structure in which the axial distance P ₁ (> P) between the centers of the balls 4 and 4 in both rows is large, Depending on the above operation, the maximum diameter portions of the balls 4 and 4 in both rows cannot be distributed to both axial sides of both bank portions 10a and 12a. It is necessary to make the axial distance P larger than the diameter Da of the balls 4 and 4 in order to prevent the balls 4 and 4 in both rows from interfering with each other.

Further, in the case of this example, since the finishing process is applied to the inner peripheral surface of the outer ring 2a and the outer peripheral surface of the inner ring 3a, as described above, each of these balls 4 and 4 is assembled at the time of assembling work. In addition to preventing the rolling surfaces of the balls 4 and 4 from being damaged, it is possible to prevent hard oxide film fragments that have fallen off from the two peripheral surfaces during the assembling operation from being mixed into the lubricant.
Furthermore, in the case of this example, the curvature radii of the cross-sectional shapes of the outer ring raceways 6 and 6 and the inner ring raceways 7 and 7 are appropriately regulated in relation to the diameter Da of the balls 4 and 4. Therefore, while suppressing the contact surface pressure of the rolling contact portion between the raceways 6 and 7 and the rolling surfaces of the balls 4 and 4, the rolling surfaces of the balls 4 and 4 are excessively large due to edge load. It is possible to prevent the surface pressure from acting, and it is possible to improve the rolling fatigue life of the rolling surfaces of the balls 4 and 4 and thus improve the durability of the double row ball bearing 1a incorporating these balls.

Sectional drawing of the double row ball bearing which shows one example of embodiment of this invention. The X section enlarged view of FIG. The figure which looked at a part of retainer from the diameter direction. The fragmentary sectional view of an outer ring | wheel which shows the site | part which performs machining, such as grinding | polishing. The perspective view of the holding jig used for the assembling work of each ball. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the reason which can attain the ease of the assembly | attachment operation | work of a ball | bowl by this invention, (A) shows the case of this invention, (B) shows the case of a conventional structure, respectively. FIG. The partial cut perspective view which shows an example of the double row ball bearing conventionally known. Similarly sectional drawing. Sectional drawing which shows the state which incorporates a ball between an outer ring track and an inner ring track.

DESCRIPTION OF SYMBOLS 1, 1a Double row ball bearing 2, 2a Outer ring 3, 3a Inner ring 4 Ball 5, 5a Cage 6 Outer ring raceway 7 Inner ring raceway 8 Pocket 9 Elastic claw part 10, 10a Outer diameter side center bank part 11 Outer diameter side continuous part 12 12a Inner diameter side central bank portion 13 Inner diameter side continuous portion 14 Holding jig 15 Base portion 16 Holding arm portion 17 Locking groove 18 Retaining ring

Claims (1)

An outer ring having a double row outer ring raceway on the inner peripheral surface, an inner ring having a double row inner ring raceway on the outer peripheral surface, and a plurality of rollings for each row between the outer ring raceways and the inner ring raceways. A ball provided freely, and a pair of cages for holding each of these balls so as to roll freely. The ball is incorporated in an engine starter for an idling stop vehicle, and a one-way clutch around a crankshaft. In the double-row ball bearing that rotatably supports the inner ring for clutch that constitutes
The outer peripheral surface of the outer ring and the outer peripheral surface of the inner ring have their surfaces removed by machining performed after heat treatment, so that the oxide film formed by this heat treatment is removed,
The pair of cages is made of a true gate type, which is a multi-gate type in which molten resin is fed into a cavity for injection molding from a plurality of locations in the circumferential direction or a disc gate type in which the inner circumference side is almost entirely surrounded. It is a crown type cage made of synthetic resin having a circularity of 0.30 mm or less,
The diameter of each ball is Da,
Let PCD be the diameter of the pitch circle of each ball ,
Let Z be the number of balls in each row above,
The axial distance between the centers of the balls in both rows is P,
The width in the axial direction of the double row ball bearing is B,
The thickness in the radial direction of the outer ring and T _2,
The thickness in the radial direction of the inner ring and T _3,
The thickness in the radial direction of both cage and T _5,
The thickness in the radial direction of the outer ring raceway portion of the outer ring and t _2,
When the thickness in the radial direction of the inner ring raceway portion of the inner ring is t ₃ ,
(Z · Da) / (π · PCD) = 0.20 to 0.35, and
Da <P <1.25 Da, and
B = (2.8-3.2) Da, and
PCD = (17-24) Da, and
PCD / T ₂ = 25 to 35, and
PCD / T ₃ = 25 to 35, and
PCD / T ₅ = 40-50, and
T ₂ > T ₃ and
t ₂ > t ₃
Double-row ball bearing characterized by satisfying the relationship

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