KR100733438B1 - Bearing apparatus for supporting pinion shaft - Google Patents

Abstract

The pinion shaft support bearing device includes a pair of rolling bearings arranged axially side by side between a pinion gear disposed on one end of the pinion shaft and a companion flange disposed outside the other end of the pinion shaft so as to rotatably support the pinion shaft to the case. It includes. The rolling bearing on the companion flange side includes an angular contact ball bearing, wherein the radius of curvature Ri of the inner raceway, the radius of curvature Ro of the outer raceway, and the ball diameter Bd of the rolling bearing are expressed by the formula Ri <Ro, 0.502. The relationship given by x Bd <Ri <0.512 x Bd, and 0.510 x Bd <Ro <0.520 x Bd can be satisfied.

Description

BEARING APPARATUS FOR SUPPORTING PINION SHAFT}

The present invention relates to a pinion shaft support bearing device for rotatably supporting pinion shafts constituting a differential mechanism of a vehicle, a transfer mechanism for a four-wheel drive vehicle, and the like.

In a differential mechanism of a vehicle or a transfer mechanism for a four-wheel drive vehicle, a configuration has been conventionally proposed in which the pinion shaft is rotatably supported by a tapered roller bearing on each of the pinion gear side and the companion flange side (for example, Japan). See Patent Publications Nos. 9-105450 and 10-220468). In the case of such a differential mechanism and a transfer mechanism, tapered roller bearings with a large load capacity are used for rolling bearings on the pinion gear side or the companion flange side.

If tapered roller bearings with a large load capacity are used, there will be a possibility that the frictional resistance increases and the driving torque increases, thereby affecting the fuel consumption of the vehicle.

According to the present invention, as long as the bearing device for supporting the pinion shaft is disposed axially side by side between the pinion gear rotatably supporting the pinion shaft relative to the case and disposed on one end of the pinion shaft and the companion flange attached to the outside of the other end of the pinion shaft. An angular contact ball bearing comprising a pair of rolling bearings, including an inner ring fixed to the pinion shaft, an outer ring fixed to the case, and a set of balls interposed between these inner and outer rings, for rolling bearings on the companion flange side. The relationship between the radius of curvature Ri of the inner ring raceway, the radius of curvature Ro of the outer ring raceways and the ball diameter Bd of the rolling bearing on the companion flange side

Ri <Ro

502 × Bd ≤ Ri ≤ 0.512 × Bd

510 × Bd ≤ Ro ≤ 0.520 × Bd

Characterized by satisfying.

In addition, the contact angle θ between the outer ring raceway and the inner ring raceway and the ball in the rolling bearing on the companion flange side satisfies, for example, 30 ° ≦ Θ ≦ 45 °.

The ball bearings constituting the rolling bearing on the companion flange side include angular contact ball bearings having a single track, tandem angular contact ball bearings having a double row track, and the like.

The bearing device of the present invention is applied to a part included in a differential mechanism, a transfer mechanism, and the like. For example, when applied to a differential mechanism, a companion flange is used as a companion flange connected to a propulsion shaft, and when applied to a transfer mechanism, the companion flange is a rear wheel. Used as an output flange that connects to a differential gear.

Lubrication for the bearing device can be either oil lubrication as the oil flows out as the ring gear in the differential holding shield is supplied to the bearing device or grease lubrication by the bearing device.

According to the bearing device for pinion shaft support of the present invention, since the load of the rolling bearing on the companion flange side is smaller than the load of the rolling bearing on the pinion gear side, the angular contact ball bearing having a small load capacity is used for the rolling bearing on the companion flange side. Used as The frictional resistance of the angular contact ball bearings is smaller than the frictional resistance of the tapered roller bearings, thus reducing the operating torque.

Further, the relationship between the radius of curvature Ri of the inner raceway, the radius of curvature Ro of the outer raceway and the ball diameter Bd of the rolling bearing on the companion flange side

Ri <Ro

0.502 × Bd ≤ Ri ≤ 0.512 × Bd

0.510 × Bd ≤ Ro ≤ 0.520 × Bd

Satisfies

Typically, the radius of curvature Ri 'of the inner raceway and the radius of curvature Ro' of the outer raceway are given as follows.

0.515 × Bd ≤ Ri '≤ 0.525 × Bd

0.525 × Bd ≤ Ro '≤ 0.535 × Bd

Both the radius of curvature Ri of the inner ring raceway and the radius of curvature Ro of the outer ring raceway of the present invention become smaller than typical values. Therefore, the contact area between the ball and the inner raceway and the outer raceway increases (increased oil level), so that the contact pressure decreases, thus making it difficult to generate indentations on the raceway surface.

Moreover, the contact angle Θ between the inner ring raceway and the outer ring raceway and the ball in the rolling bearing on the companion flange side satisfies, for example, 30 ° ≦ Θ ≦ 45 °. In general, in the angular contact ball bearing for high speed rotation, the contact angle Θ 'between the ball, the inner ring raceway and the outer ring raceway is 20 ° ≤ Θ' ≤ 25 °, so that the contact angle Θ of the present invention becomes larger than a typical value. The load capacity for axial loads increases. In addition, since the contact angle Θ increases, the shoulder diameter of the inner ring also increases, so that the contact surface can be sufficiently fixed together with the companion flange, and thus the inner ring can be reliably fixed by the companion flange.

1 is a cross-sectional view of a differential mechanism to which a pinion shaft support bearing device of a first embodiment of the present invention is applied.

FIG. 2 is a partially enlarged cross-sectional view of the pinion shaft support bearing device shown in FIG. 1. FIG.

3 is an enlarged cross-sectional view of a rolling bearing on the companion flange side of the pinion shaft support bearing device shown in FIG. 1.

4 is a partially enlarged cross-sectional view of a modification of the pinion shaft support bearing device of the first embodiment of the present invention.

Fig. 5 is a sectional view of a differential mechanism to which the pinion shaft support bearing device of the second embodiment of the present invention is applied.

FIG. 6 is a partially enlarged cross-sectional view of the pinion shaft support bearing device shown in FIG. 5.

7 is an enlarged cross-sectional view of the seal portion of the pinion shaft support bearing device shown in FIG. 5.

8 is a partially enlarged cross-sectional view of a modification of the pinion shaft support bearing device of the second embodiment of the present invention.

9 is a partially enlarged sectional view of another modification of the pinion shaft support bearing device of the second embodiment of the present invention.

Fig. 10 is a sectional view of a differential mechanism applied to the pinion shaft support bearing device of the third embodiment of the present invention.

FIG. 11 is a partially enlarged cross-sectional view of the pinion shaft support bearing device shown in FIG. 10.

12 is a partially enlarged cross-sectional view of a modification of the pinion shaft support bearing device of the third embodiment of the present invention.

Hereinafter, a pinion shaft support bearing device according to a preferred embodiment of the present invention (called a first embodiment) will be described with reference to the drawings. 1 shows a sectional view of a differential mechanism to which a pinion shaft support bearing device according to a first embodiment is applied, and FIG. 2 shows a partially enlarged sectional view of the pinion shaft support bearing device shown in FIG. 1.

1 and 2, reference numeral 1 denotes a differential holding shield, a differential transmission mechanism 2 which differentially interlocks the right wheel and the left wheel, a pinion gear 3, and a pinion shaft ( 4) and rolling bearings 5 and 6 for rotatably supporting the pinion shaft 4 are housed in this differential holding shield 1.

The pinion gear 3 is fastened to the ring gear 2a of the differential transmission mechanism 2 and is formed integrally with the tow of the pinion shaft 4. The pinion shaft 4 is rotatably supported inside the differential holding shield 1 by a pair of rolling bearings 5 and 6 arranged so that the rear surfaces face each other, and a companion flange to which a propulsion shaft (not shown) is connected. 7 is arranged on the wheel.

The rolling bearings 5, 6 are respectively fitted on the inner circumferential surfaces of the annular walls 13, 14 for fitting the bearings formed in the front bearing case portion 1a of the differential holding shield 1. The rolling bearing 5 on the companion flange 7 side is included in the opening on the small diameter side of the bearing case portion 1a, and the rolling bearing 6 on the pinion gear 3 side of the bearing case portion 1a. It is included in the opening part on the large diameter side, and the positioning spacer 8 is interposed between the rolling bearings 5 and 6 of both. The nut 15 is screwed onto the wheel of the pinion shaft 4 so as to be fixed to the companion flange 7 so that the pinion gear 3 and the companion flange (with the preload force applied to the rolling bearings 5 and 6) are applied. 7) is fixed in between.

The lubricating oil is stored at the L level in the differential holding shield 1 at standstill. The oil flows out as the ring gear 2a rotates during operation, and then the rolling bearings 5, 6 through the oil inflow path 11 formed between the annular walls 13, 14 in the bearing case portion 1a. Is introduced, and is also returned via an oil return path (not shown). In addition, an oil leak preventing oil seal 9 is sandwiched between the outer circumferential surface on the wheel side of the pinion shaft 4 and the inner circumferential surface of the bearing case portion 1a, and the seal protective cup 10 for protecting the oil seal 9. Is attached.

The rolling bearing 5 comprises a set of balls 53 held by an inner ring 51, an outer ring 52 and a cage 54. The rolling bearing 6 comprises a set of tapered rollers 63 held by an inner ring 61, an outer ring 62 and a cage 64.

The spline 71 is formed on the inner circumferential surface of the main body attached to the outside of the pinion shaft 4 on the companion flange 7 side, and the end face of the inner ring 51 in the rolling bearing 5 passes through the pinion gear 3. The pressing portion 72 of the annular projection pressing in the direction of () is integrally formed on the outer circumferential surface of the upper portion of the main body.

The outer ring 52 of the rolling bearing 5 is press-mounted into one annular wall 13, the outer ring 62 of the rolling bearing 6 is press-mounted into the other annular wall 14 and the tapered roller 63. In the state where the set is set and the inner ring 61 on which the cage 64 of the rolling bearing 6 is set is attached to the outside of the pinion shaft 4, the pinion shaft 4 is the large diameter portion of the bearing case portion 1a. It is inserted from the opening on the side. In addition, the inner ring 51 in which the spacer 8 and the set of balls 53 and the cage 54 are set is mounted around the pinion shaft 4 from the opening on the small diameter side of the bearing case portion 1a. . The companion flange 7 is then spline-fitted to the small diameter portion 41 on the drive shaft of the pinion shaft 4. Further, the nut 15 is screwed onto the side edge of the drive shaft at the pinion shaft 4 so as to be fixed to the companion flange 7.

Accordingly, the pressing portion 72 of the companion flange 7 contacts the end face of the inner ring 51 in the rolling bearing 5 to press the inner ring 51 in the direction of the pinion gear 3. As a result, the rolling bearings 5, 6 arranged side by side in the axial direction via the spacer 8 are inserted between the pinion gear 3 and the companion flange 7 with a preload applied to the pinion shaft 4. It is fixed to).

With reference to Figure 3 will be described in detail the features of the present invention. In the present invention, the rolling bearing 5 on the companion flange 7 side is made of an angular contact ball bearing having a single track.

If the radius of curvature of the raceway 55 of the inner ring 51 is Ri, the radius of curvature of the raceway 56 of the outer ring 52 is Ro, and the diameter 53 of the ball is Bd, the relationship between them is expressed by the following equation (1) , (2) and (3).

Ri <Ro (1)

0.502 × Bd ≤ Ri ≤ 0.512 × Bd (2)

0.510 × Bd ≤ Ro ≤ 0.520 × Bd (3)

Usually, the radius of curvature Ro is set to about 1% larger than the radius of curvature Ri. For example, for Ri = 0.505 x Bd, Ro = 0.515 x Bd.

The contact angle Θ between the ball 53 and the inner ring 51 and the outer ring 52 is a radius of action A and a line connecting the two points at which the ball 53 contacts the inner track 55 and the outer track 56. It is an angle Θ between the directional planes, and this angle Θ has a relationship of the following equation (4).

30 ° ≤ Θ ≤ 45 ° (4)

In particular, the contact angle Θ is set to one of Θ = 30 °, 35 °, 40 ° or 45 °.

In addition, the relationship of Formula (4) is not specifically limited only to this range.

According to the bearing device for supporting pinion shafts configured as described above, since the load of the rolling bearing 5 on the companion flange 7 side is smaller than the load of the rolling bearing 6 on the pinion gear 3 side, the load capacity This small angular contact ball bearing is used for the rolling bearing 5 on the companion flange 7 side. The frictional resistance of the angular contact ball bearing is smaller than the frictional resistance of the tapered roller bearings, thus reducing the driving torque, thereby improving the fuel consumption of the vehicle.

Further, as shown in the above formulas (2) and (3), both the radius of curvature Ri of the inner ring raceway 55 and the radius of curvature Ro of the outer ring raceway 56 are formed smaller than typical values, and thus The contact area between the ball 53, the inner ring raceway 55, and the outer ring raceway 56 is increased (increasing the oil level), so that the contact pressure is reduced, thereby making it difficult to generate indentations on the raceway surface.

In addition, as shown in Equation (4) above, the contact angle Θ is formed larger than the typical value, thus increasing the load carrying capacity with respect to the axial load. Furthermore, as the contact angle Θ increases, the shoulder diameter D (see Fig. 3) of the inner ring 51 also increases, so that the pressing portion 72 of the companion flange 7 at the end face of the inner ring 51 is increased. And the contact surface can be sufficiently secured, whereby the inner ring 51 can be reliably fixed by the companion flange 7.

Moreover, since the angular contact ball bearing is used as the rolling bearing 5, the number of balls can be increased compared to the number of balls of deep groove ball bearings, and thus net-rated load. ), Thereby ensuring sufficient bearing life.

In addition, instead of the nut 15, the side edges of the drive shaft in the pinion shaft 4 can be fixed to fix the rolling bearings 5, 6 to the pinion shaft 4.

As shown in Fig. 4, the rolling bearing 6 on the pinion gear side may be a tandem angular contact ball bearing with a double row track. The tandem ball bearing means that the diameter PCD of the circle formed by connecting the center of the balls 63 in each row PCD is different.

In other words, the rolling bearing 6 comprises an inner ring 61, an outer ring 62 and a set of two rows of balls 63 each of which is held by a cage 64. A pair of inner ring raceways 65 and 66 and a pair of outer ring raceways 67 and 68 are formed in the inner ring 61 and the outer ring 62, respectively, and the PCD of the set of balls 63 on the pinion gear side is a counter pinion. It can be larger than the PCD on the gear side.

The other configuration is similar to that of the example shown in Figs.

Therefore, the rolling bearing 6 on the pinion gear side is made of a tandem angular contact ball bearing, so that the torque reduction of the tandem angular contact ball bearing can be obtained more than the torque reduction of the tapered roller bearing. Moreover, the rolling bearing 6 consists of a tandem angular contact ball bearing with a double row track, and thus it is possible to obtain more miniaturization of the bearing device compared to a pair of angular contact ball bearings arranged side by side with a single track.

In addition, in the rolling bearing 6 on the pinion gear side, when the radius of curvature of the inner ring raceways 65 and 66 is Ri, the radius of curvature of the outer ring raceways 67 and 68 is Ro, and the diameter of the ball is Bd, the rolling bearing Is configured to satisfy the relationship of the formulas (1), (2), and (3). Moreover, the contact angle Θ between each ball 63 and the inner ring 61 and the outer ring 62 will satisfy the above equation (4).

5 to 7, a second embodiment of the present invention will be described.

FIG. 5 is a cross-sectional view of a differential mechanism to which the pinion shaft support bearing device of the second embodiment is applied, FIG. 6 is a partially enlarged cross-sectional view of the pinion shaft support bearing device shown in FIG. 5, and FIG. 7 is shown in FIG. 5. Sectional drawing of the seal part of the pinion shaft support bearing device.

The pinion shaft support bearing device of the second embodiment includes a tandem ball bearing in which the rolling bearing 5 on the companion flange side has an angular contact ball bearing, and the rolling bearing 6 on the pinion gear side has a double row track. A contact ball bearing, characterized in that the grease G is filled in the space between the rolling bearings 5, 6.

In addition, since the other components are similar to those of the illustrated example shown in FIG. 3, the same components will be denoted by the same reference numerals and description thereof will be omitted.

The rolling bearing 5 comprises an inner ring 51 having an inner ring raceway 55, an outer ring 52 having an outer ring raceway 56, and a set of balls 53 held by the cage 54, and rolling The bearing 6 includes an inner ring 61 having a pair of inner ring raceways 65 and 66, an outer ring 62 having a pair of outer ring raceways 67 and 68, and two held by a cage 64. A row of ball 63 sets, wherein the side edges of the companion flanges in the rolling bearings 5 and the side edges of the pinion gears in the rolling bearings 6 are sealed by seal members 59 and 69, respectively. . Grease G is filled in the space between the rolling bearings 5, 6 sealed by the seal members 59, 69. The rolling bearing 5 satisfies the relationship between the above equations (1) to (3) as shown in FIG. 3, which bearing can also be configured to satisfy the above equation (4).

In addition, the rolling bearing 6 may also be configured to satisfy the relationship between the above equations (1) to (3), and also to satisfy the above equation (4) as also described in the example shown in FIG. .

The seal member 59 disposed on the companion flange side is of a type called bearing seal, and the seal member 69 disposed on the pinion gear side is of a type called oil seal.

The seal members 59 and 69 are formed by vulcanizing and bonding the elastic bodies 59b and 69b such as rubber to the annular core rings 59a and 69a, respectively, and contacting the inner ring 51 and 61 in a state of having a predetermined tight coupling force. Lip portions 59c and 69c are formed in elastic bodies 59b and 69b. In addition, the lip portions 59c and 69c are openable toward the outside of the bearing to mainly prevent foreign material from entering the outside of the bearing.

In addition, the lip portion 69c is forcibly pushed toward the inner ring 61 by the spring ring 69d, so that the seal member 69 improves the seal performance as much as possible, thereby ensuring that oil enters the bearing interior. You can prevent it.

The spring ring or the like is not used for the seal member 59, and the inner diameter of the lip portion 59c is set to be smaller than the outer diameter of the shoulder portion only at the inner ring 51 by a predetermined amount, so that the lip portion 59c has an outer diameter tolerance. It is formed to contact the inner ring 51 in a state in which it is elastically expanded by the variation of. In addition, the lip portion may be configured such that an air hole communicating with the inner and outer sides of the bearing is formed in the seal member 59, and the lip portion 59c protrudes to the outer diameter of the shoulder of the inner ring 51 due to the pressure difference between the inner and outer sides of the bearing. Is prevented.

Acrylic rubber, heat resistant acrylic rubber and the like are preferably used for the respective elastic bodies 59b and 69b corresponding to the seal members 59 and 69, respectively. The heat resistant acrylic rubber may be ethylene acrylic rubber in which ethylene and acrylic ester are combined as the copolymer base composition.

In addition, in consideration of heat resistance, it is preferable that diurea type grease or ester type grease having desired similarity to gear oil is used as grease G filled in the inside of the bearing device. In particular, for example, Japan Grease Co. Trade name KNG170 or Yusi Co. It is suitable to use the trade name MULTEMP SRL manufactured by Ltd. KNG170 is prepared by using poly alpha -olefin mineral as base oil and diurea as thickening agent, and has an operating temperature limit of -30 to 150 ° C. MULTEMP SRL is prepared using esters as base oils and lithium soaps as a starting agent, with an operating temperature limit of -40 to 130 ° C.

In addition, in the pinion shaft support bearing device configured as described above, the driving torque is reduced, and thus the fuel consumption of the vehicle is improved.

Moreover, since grease lubrication is used instead of oil lubrication, it is not necessary to form an oil inflow path or an oil return path in the differential holding case 1 like oil lubrication, thereby reducing the size and weight of the differential mechanism. In addition, the bearing life can be improved because the bearing device is not affected by foreign matter in the oil of the differential mechanism.

As shown in FIG. 8, the rolling bearing 6 on the pinion gear side can be a combination of two angular contact ball bearings with a single track.

That is, the rolling bearing 6 is a pair of inner ring 61, a pair of outer ring 62, each of which is held by a cage 64, interposed between each of the inner ring 61 and outer ring 62 Two rows of balls (63).

In addition, the other configuration is similar to that of the example shown in FIGS. 5 to 7.

Also in this example, the ball bearings in each row of the rolling bearing 6 are also configured to satisfy the relationship between the above formulas (1) to (3), and are further configured to satisfy the above formula (4).

As shown in FIG. 9, the pinion shaft 4 can be rotatably supported by the bearing unit 100 on the differential holding shield 1.

The bearing unit 100 comprises a rolling bearing 5 having an angular contact ball bearing with a single track on the companion flange side and a rolling bearing 6 with a tandem angular contact ball bearing with a double row track on the pinion gear side. do. That is, the rolling bearing 5 includes a set of balls 53 held by an inner ring 51, an outer ring 101, and a cage 54, and the rolling bearing 6 includes an inner ring 61, an outer ring 101. ), And a set of two rows of balls 63, each held by a cage 64. An inner ring raceway 55 is formed in the inner ring 51, a pair of inner ring raceways 65, 66 are formed in the inner ring 61, and three outer ring raceways 56, 67, and 68 are formed in the outer ring 101. Is formed. The bearing unit 100 is formed of a unit in which two inner rings 51 and 61 are axially matched, and grease G is filled, and then both ends in the axial direction are sealed by the seal members 59 and 69. Sealed, the outer ring 101 is formed in a single type.

In addition, the inner ring raceway 55, the outer ring raceway 56, and the set of balls 63 constituting the rolling bearing 5 are configured to satisfy the relationship of Equations (1) to (3) above. It can be configured to satisfy the above formula (4) as shown in 3.

Precise preload adjustment of the bearing unit 100 is carried out during the manufacturing phase, first of which a set of balls 53, 63 is held by the inner race 51, 61, the outer race 101, and the cage 54, 64. By attachment.

Thereafter, the rolling bearings 5 and 6 are attached to the outer side around the pinion shaft 4 so that the bearing unit 100 is mounted around the pinion shaft, and the pinion shaft 4 is inserted from the drive shaft side. The companion flange 7 is splined to the small diameter portion 41 on the drive shaft side of the pinion shaft 4, after which the side edge portion of the drive shaft on the pinion shaft 4 is fixed radially outward, and the companion flange 7 ) Is clamped tightly in the direction of the pinion gear by the corresponding caulking 16. Accordingly, the companion flange 7 contacts the end face of the inner ring 51 in the rolling bearing 5, and the inner ring 51 is pressed in the pinion gear direction. As a result, the inner rings 51 and 61 are inserted between the pinion gear 3 and the companion flange 7 and fixed to the pinion shaft 4 in a state in which a preload is applied. Moreover, a flange 102 formed around the outer ring 101 is fixed to the differential holding shield 10 by bolts 103.

In addition, the other configuration is similar to that of the example shown in FIGS. 5 to 7.

In this example also, the rolling bearing 6 is configured to satisfy the relationship between the above formulas (1) to (3), and is further configured to satisfy the above formula (4).

10 and 11, a third embodiment of the present invention will be described.

Fig. 10 is a sectional view of a differential mechanism to which the pinion shaft support bearing device of the third embodiment is applied, and Fig. 11 shows a partially enlarged sectional view of the pinion shaft support ball bearing device shown in Fig. 10.

The pinion shaft support bearing device of the third embodiment is characterized in that the rolling bearing 5 on the companion flange side is composed of a tandem angular contact ball bearing with a double row track used as an angular contact ball bearing.

In addition, since the other components are similar to those of the example in FIG. 3, the same components are denoted by the same reference numerals, and description thereof will be omitted.

The rolling bearing 5 has an inner ring 51 having a pair of inner ring raceways 55, 57, an outer ring 52 having a pair of outer ring raceways 56, 58, and each of which is driven by a cage 54. And a set of two rows of balls 53 to be maintained.

When the radius of curvature of each of the inner ring raceways 55 and 57 constituting the rolling bearing 5, the radius of curvature of the outer ring raceways 56 and 58, and the diameter of the ball 53 are Ri, Ro, and Bd, respectively, The relationship of Formulas (1) to (3) is satisfied. Moreover, the contact angle Θ between each of the balls 53 and the inner ring 51 and the outer ring 52 is set to satisfy the above expression (4).

In the pinion shaft support bearing device configured as described above, driving torque can also be reduced, thereby improving fuel consumption of the vehicle. Furthermore, tandem angular contact ball bearings with double row tracks are used for rolling bearings (5), bearing life, safety against dead load, and stiffness compared to angular contact ball bearings with single tracks. Better than Further, compared with arranging a pair of angular contact ball bearings having a single track side by side, adjustment by a skilled person is unnecessary and can be easily assembled.

As shown in Fig. 12, the rolling bearing 6 on the pinion gear side may be a tandem angular contact ball bearing with a double row track.

That is, the rolling bearing 6 has an inner ring 61 having a pair of inner ring raceways 65 and 66, an outer ring 62 having a pair of outer ring raceways 67 and 68, and each of which has a cage 64. And a set of two rows of balls 63 held by.

In addition, the other configuration is similar to that of the example shown in FIGS. 10 to 11.

In this example also, the rolling bearing 6 is also configured to satisfy the relationship between the above formulas (1) to (3), and may further be configured to satisfy the above formula (4).

In addition, in each of the above embodiments, the rolling bearing 6 on the pinion gear side includes an angular contact ball bearing with a single track, a combination of various radial and thrust bearings, various radial and angular contact balls. Combinations of bearings, or other than the bearings included in, for example, the above embodiments.

According to the bearing device for supporting the pinion shaft, the driving torque can be reduced, whereby the fuel consumption improvement effect of the vehicle is achieved.

The present invention can be used for a pinion shaft support bearing device for rotatably supporting pinions constituting a differential mechanism of a vehicle, a transfer mechanism for a four-wheel drive vehicle, and the like.

Claims (7)

And a pair of rolling bearings arranged axially side by side between the pinion gear rotatably supporting the pinion shaft in the case and a companion flange attached to the outside of the other end of the pinion shaft. As a bearing device for supporting pinion shafts, The rolling bearing on the companion flange side includes an angular contact ball bearing having an inner ring fixed to the pinion shaft, an outer ring fixed to the case, and a ball set interposed between these inner and outer rings, The relationship between the radius of curvature Ri of the inner raceway, the radius of curvature Ro of the outer raceway, and the ball diameter Bd of the rolling bearing on the companion flange side Ri <Ro 0.502 × Bd <Ri <0.512 × Bd, and 0.510 × Bd ≤ Ro ≤ 0.520 × Bd Pinion shaft support bearing device to satisfy. The pinion shaft support bearing device according to claim 1, wherein in the rolling bearing on the companion flange side, the contact angle (Θ) between the ball and the inner raceway and the outer raceway satisfies 30 ° ≤Θ≤45 °. 2. The pinion shaft support bearing device according to claim 1, wherein the rolling bearing on the companion flange side comprises an angular contact ball bearing with a single track or a tandem angular contact ball bearing with a double row track. 4. The pinion shaft support bearing device of claim 3, wherein the rolling bearing on the pinion shaft side comprises a conical rolling bearing with a single track. 4. The pinion shaft supporting bearing device according to claim 3, wherein the rolling bearing on the pinion shaft side includes a tandem angular contact ball bearing having a double row track. 4. The pinion shaft support bearing device according to claim 3, wherein the rolling bearing on the pinion shaft side comprises a combination of two angular contact ball bearings having a single track. A bearing unit comprising a rolling bearing on the companion flange side having an angular contact ball bearing with a single raceway and a rolling bearing on the pinion gear side with a tandem angular contact ball bearing with a double row raceway and supporting the pinion shaft to the differential holding shield; As The rolling bearings both comprise a common outer ring as a single outer ring, The relationship between the ball diameter Bd of the rolling bearing on the companion flange side, the radius of curvature Ri of the inner raceway and the radius of curvature Ro of the outer raceway Ri <Ro 0.502 × Bd <Ri <0.512 × Bd, and 0.510 × Bd ≤ Ro ≤ 0.520 × Bd Pinion shaft support bearing unit to satisfy the.

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