JP4345304B2 - Differential - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a differential device that makes a difference in rotation between left and right wheels, and more particularly, to a differential device having an improved rolling bearing.
[0002]
[Prior art]
As a differential device, a pinion shaft rotatably supported by a differential carrier and having a pinion gear disposed at one end thereof, a ring gear meshed with the pinion gear, and a ring gear attached to the ring gear A differential case and a pair of rolling bearings that rotatably support the differential case on a differential carrier are used.
[0003]
Rolling bearings of differential devices have been conventionally tapered roller bearings in order to obtain high rigidity. However, lowering the torque of bearings has been an issue from the viewpoint of improving fuel efficiency, and rotational torque is smaller than tapered roller bearings. It has been proposed to use ball bearings. (See Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-161466
[Problems to be solved by the invention]
In a differential device using a ball bearing, the rigidity is usually lower than that of a tapered roller bearing, so that the manufacturing cost is increased by changing the material to achieve both low torque and high rigidity. A new problem arises, and there is a demand for a differential device having a bearing that can solve this new problem and can further reduce torque.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a differential device that uses a low torque bearing instead of a tapered roller bearing to improve fuel efficiency and improve the cost increase problem.
[0007]
[Means for Solving the Problems and Effects of the Invention]
The differential according to the present invention includes a pinion shaft rotatably supported on a differential carrier and having a pinion gear disposed at one end thereof, a ring gear meshed with the pinion gear, and a ring gear. A differential device comprising an attached differential case and a pair of rolling bearings rotatably supporting the differential case on a differential carrier, wherein at least a pinion gear of the pair of rolling bearings The double row oblique contact ball bearing is the one on the side farther from the meshing position with the ring gear . The double row oblique contact ball bearing has an inner ring raceway diameter and an outer ring raceway diameter on the side far from the pinion gear. It has been made smaller respectively than the inner ring raceway diameter and the outer ring raceway diameter of the side close to the contact angle of each row of oblique contact ball bearing And the inner ring raceway curvature is smaller than 51.5% and larger than 50%, and the outer ring raceway curvature is smaller than 52.5% and larger than 50%. It is what.
[0008]
The double row oblique contact ball bearing has, for example, an inner ring and an outer ring formed integrally with each other, and two rows of balls arranged between the two rings, and one inner ring raceway diameter and an outer ring raceway diameter are the other inner ring raceways. The inner ring and the outer ring may be formed smaller than the diameter and the outer ring raceway diameter, respectively, and the inner ring and the outer ring formed integrally with each other, and two rows of balls arranged between the two rings may be provided. The track diameter and outer ring track diameter may be equal to the other inner ring track diameter and outer ring track diameter.
[0009]
Double row oblique contact ball bearings with the same contact angle on the side far from the gear meshing position, and rolling bearings with the same contact side (double row oblique contact ball bearings or cones with the same contact angle on each row) Roller bearings are used face to face.
[0010]
According to the differential of the present invention, since at least one of the rolling bearings is an oblique contact ball bearing, the rotational torque is smaller than that of the tapered roller bearing, and fuel consumption can be improved. By making the contact angle of each row in the same direction, the load capacity of the thrust load increases, which is advantageous in terms of load capacity and rigidity, and it is possible to achieve both low torque and high rigidity. In addition, double row oblique contact ball bearings themselves having the same contact angle in each row are known and can be easily manufactured, and it is not necessary to take measures such as changing the material to ceramic. Without both, low torque and high rigidity can be achieved.
[0011]
The track curvature of the inner ring of the oblique contact ball bearing is preferably smaller than 51.5% and larger than 50% of the ball diameter. The raceway curvature of the inner ring of the oblique contact ball bearing has been conventionally larger than 51.5% and smaller than 52.5% of the ball diameter, but by making this less than 51.5% of the ball diameter, The contact surface pressure between the ball and the inner ring can be reduced, and the outer dimensions of the bearing can be reduced. Therefore, it is possible to obtain the effect of reducing the torque by reducing the outer dimension. A more preferable range of the raceway curvature of the inner ring is 50.5% or more of the ball diameter and 51% or less of the ball diameter. For the same reason, the raceway curvature of the outer ring of the oblique contact ball bearing is conventionally larger than 52.5% and smaller than 53.5%, but from 52.5% of the ball diameter. Is preferably smaller and larger than 50%, and a more preferable range of the raceway curvature of the outer ring is 51.5% or more of the ball diameter and 52% or less of the ball diameter.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In the following description, the left and right refer to the left and right in the figure.
[0013]
FIG. 1 shows a first embodiment of a differential device according to the present invention. The differential device is rotatably supported by a differential carrier (1) and a drive pinion gear (3) is arranged at one end. The installed pinion shaft (2), the ring gear (4) meshed with the drive pinion gear (3), the differential case (5) attached to the ring gear (4), and the differential gear A pair of left and right rolling bearings (10) and (11) that rotatably support the case (5) on the differential carrier (1), and left and right side gear shafts (6) extending from the differential case (5) to the left and right A side gear (7) disposed at each inner end portion and a differential pinion gear (8) rotatably supported by the spider (9) and meshed with the side gear (7) are provided.
[0014]
The left rolling bearing (10), that is, the bearing close to the meshing position of the drive pinion gear (3) and the ring gear (4) is an inner ring (12) fixed to the outer periphery of the left end of the differential case (5). ), An outer ring (13) fixed to the differential carrier (1) at a position facing the inner ring (12), a plurality of tapered rollers (14) disposed between the two rings (12) (13), and a cage (15 ) With single row tapered roller bearings.
[0015]
The right rolling bearing (11), that is, the bearing far from the meshing position of the drive pinion gear (3) and the ring gear (4) is an inner ring (16) fixed to the outer periphery of the right end of the differential case (5). ), An outer ring (17) fixed to the differential carrier (1) at a position facing the inner ring (16), a plurality of balls (18) arranged in two rows between both wheels (16) and (17), and a cage A double-row tandem oblique contact ball bearing with the contact angle (19) having the same direction is provided.
[0016]
In the double row oblique contact ball bearing, the inner ring (16) and the outer ring (17) are integrally formed, and one inner ring raceway diameter and outer ring raceway diameter are equal to the other inner ring raceway diameter and outer ring raceway diameter. Has been made. A counter bore (17a) is formed only on the left side (axially inner side) of the outer ring (17), and a shoulder pad (16a) is formed only on the right side (axially outer side) of the inner ring (16). The contact angle is set within a range of 15 ° to 20 °, the orbital curvature of the inner ring (16) is 51% or less of the ball (18) diameter, and the orbital curvature of the outer ring (17) is the ball diameter. Of 52% or less. Such an oblique contact ball bearing, for example, holds the ball (18) on the track on the right side of the outer ring (17) via the cage (19) and holds the cage (19 on the track on the left side of the inner ring (16). ), The ball (18) is held, and then the outer ring (17) is heated and the inner ring (16) is moved relative to the outer ring (17). The inner and outer rings (16) and (17) of the bearing are made of bearing steel, and in particular, the inner ring (16) is subjected to carbonitriding to raise its surface hardness to HRC 60 to 64 which is the same as that of the ball (18). Is preferable from the viewpoint of life in foreign oil.
[0017]
According to the differential of the first embodiment, since the right rolling bearing (11) is a double row oblique contact ball bearing, the rotational torque of the left and right rolling bearings is smaller than that of the tapered roller bearing. The fuel consumption can be improved, and in the right contact ball bearing (11), the raceway curvature of the inner ring (16) is 51% or less of the ball diameter, so that the raceway contact pressure can be suppressed. It is possible to reduce the outer dimension of the bearing. Furthermore, since the contact angle of each row of the oblique contact ball bearing (11) is the same direction, the load capacity of the thrust load is increased, which is advantageous in terms of load capacity and rigidity, and low torque and high rigidity. Both are possible. Further, since the assembly of the bearing can be performed in the same manner as a conventional tapered roller bearing, there is no need to change the process, and an increase in cost can be avoided.
[0018]
FIG. 2 shows a second embodiment of the differential according to the present invention. Since the difference from the first embodiment is only the rolling bearing, the configuration other than the rolling bearing is denoted by the same reference numeral and the description thereof is omitted, and only the rolling bearing will be described below.
[0019]
In the second embodiment, the left rolling bearing (20), that is, the bearing closer to the meshing position of the drive pinion gear (3) and the ring gear (4) is the outer periphery of the left end of the differential case (5). The inner ring (22) fixed to the inner ring (22), the outer ring (23) fixed to the differential carrier (1) at a position facing the inner ring (22), and a plurality of tapered rollers arranged between both wheels (22) (23) ( 24) and a single row tapered roller bearing provided with a cage (25).
[0020]
And the right rolling bearing (21), that is, the bearing far from the meshing position of the drive pinion gear (3) and the ring gear (4) is the inner ring fixed to the outer periphery of the right end of the differential case (5). (26), an outer ring (27) fixed to the differential carrier (1) at a position facing the inner ring (26), a plurality of balls (28) arranged in two rows between the two wheels (26) and (27), and A double row tandem type oblique contact ball bearing having a cage (29) having the same contact angle is used.
[0021]
In the double row oblique contact ball bearing, the inner ring (26) and the outer ring (27) are integrally formed, and the inner ring raceway diameter and the outer ring raceway diameter on the right side are smaller than the inner ring raceway diameter and the outer ring raceway diameter on the left side, respectively. Has been made. A counter bore (27a) is formed on the left side (axially inner side) of the outer ring (27), and a shoulder pad (26a) is formed on the right side (axially outer side) of the inner ring (26). The contact angle is set in the range of 15 ° to 20 °, the orbital curvature of the inner ring (26) is 51% or less of the ball (28) diameter, and the orbital curvature of the outer ring (27) is the ball diameter. Of 52% or less. Such an oblique contact ball bearing, for example, holds the ball (28) on the left and right raceways of either the inner ring (26) and the outer ring (27) via the cage (29), and the inner ring ( 26) and the outer ring (27) can be manufactured by relative movement. The inner and outer rings (26) and (27) of the bearing are made of bearing steel, and in particular, the inner ring (26) is subjected to carbonitriding to raise its surface hardness to HRC 60 to 64 which is the same as that of the ball (28). Is preferable from the viewpoint of life in foreign oil.
[0022]
According to the differential device of the second embodiment, since the right rolling bearing (21) is an oblique contact ball bearing, the left and right rolling bearings are smaller in torque than the tapered roller bearing, and the fuel consumption is reduced. Further, in the right oblique contact ball bearing (21), the raceway curvature of the inner ring (26) is 51% or less of the ball diameter. The outer dimension can be reduced. Furthermore, since the contact angle of each row of the oblique contact ball bearing (21) is the same direction, the load capacity of the thrust load is increased, which is advantageous in terms of load capacity and rigidity, and low torque and high rigidity. Both are possible. Further, since the assembly of the bearing can be performed in the same manner as a conventional tapered roller bearing, there is no need to change the process, and an increase in cost can be avoided.
[0023]
FIG. 3 shows a third embodiment of the differential according to the present invention. Since the difference from the first embodiment is only the rolling bearing, the configuration other than the rolling bearing is denoted by the same reference numeral and the description thereof is omitted, and only the rolling bearing will be described below.
[0024]
In the third embodiment, the left rolling bearing (30), that is, the bearing close to the meshing position of the drive pinion gear (3) and the ring gear (4) is the outer periphery of the left end portion of the differential case (5). The inner ring (32) fixed to the inner ring (32), the outer ring (33) fixed to the differential carrier (1) at a position facing the inner ring (32), and a plurality of rows arranged in two rows between both wheels (32) (33) A double-row tandem oblique contact ball bearing provided with a ball (34) and a cage (35) is provided.
[0025]
The right rolling bearing (31), that is, the bearing far from the meshing position of the drive pinion gear (3) and the ring gear (4) is an inner ring fixed to the outer periphery of the right end of the differential case (5). (36), an outer ring (37) fixed to the differential carrier (1) at a position facing the inner ring (36), a plurality of balls (38) arranged in two rows between both wheels (36) and (37), and A double-row tandem oblique contact ball bearing provided with a cage (39) is provided.
[0026]
The right and left oblique contact ball bearings (30) and (31) of the third embodiment are the same as the double row oblique contact ball bearing (21) used as the right rolling bearing of the second embodiment. The left oblique contact ball bearing (30) has an inner ring (32) and an outer ring (33) that are integrally formed, and the inner ring raceway diameter on the left side and the outer ring raceway diameter on the right side are the inner ring raceway diameters on the right side. The right bevel contact ball bearing (31) is formed integrally with the inner ring (36) and the outer ring (37), and the right inner ring raceway diameter and outer ring raceway diameter. Are smaller than the inner ring raceway diameter and the outer ring raceway diameter on the left side. In the left contact ball bearing (30), the counter bore (33a) is on the right side (axially inside) of the outer ring (33), and the shoulder shoulder (32a) is on the left side (axially outside) of the inner ring (32). In the right oblique contact ball bearing (31), the counter bore (37a) is on the left side (axially inner side) of the outer ring (37), and the shoulder is on the right side (axially outer side) of the inner ring (36). (36a) are formed. Further, in any of the oblique contact ball bearings (30) (31), the contact angle is set within a range of 15 ° to 20 °, and the raceway curvature of the inner rings (32) (36) is the ball (34) (38). ) 51% or less of the diameter, and the raceway curvature of the outer rings (33) and (37) is 52% or less of the diameter of the balls (34) and (38).
[0027]
According to the differential device of the third embodiment, since the left and right rolling bearings (30) and (31) are oblique contact ball bearings, the rotational torque of the left and right rolling bearings is smaller than that of the tapered roller bearing. The fuel consumption can be improved, and the track curvature of the inner ring (32) (36) is 51% or less of the ball diameter in the left and right oblique contact ball bearings (30) (31). The surface pressure can be suppressed, and the outer dimensions of the bearing can be reduced. Furthermore, since the contact angle of each row of bearings is the same direction, the load capacity of thrust load increases, which is advantageous in terms of load capacity and rigidity, and it is possible to achieve both low torque and high rigidity. Yes. Further, since the assembly of the bearing can be performed in the same manner as a conventional tapered roller bearing, there is no need to change the process, and an increase in cost can be avoided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a first embodiment of a differential according to the present invention.
FIG. 2 is a longitudinal sectional view showing a second embodiment of the differential according to the present invention.
FIG. 3 is a longitudinal sectional view showing a third embodiment of the differential according to the present invention.
[Explanation of symbols]
(1) Differential carrier
(2) Pinion shaft
(3) Pinion gear
(4) Ring gear
(5) Differential case
(10) (20) (30) Left rolling bearing
(11) (21) (31) Right rolling bearing

Claims (2)

A pinion shaft rotatably supported by a differential carrier and having a pinion gear disposed at one end thereof, a ring gear meshed with the pinion gear, and a differential case attached to the ring gear; In a differential having a pair of rolling bearings that rotatably support a differential case on a differential carrier,
Of the pair of rolling bearings, at least the one far from the meshing position of the pinion gear and the ring gear is a double row oblique contact ball bearing, and the double row oblique contact ball bearing is formed from the pinion gear. The inner ring raceway diameter and the outer ring raceway diameter on the far side are made smaller than the inner ring raceway diameter and the outer ring raceway diameter on the side close to the pinion gear, respectively, and the contact angle of each row of the oblique contact ball bearings is the same direction. A differential characterized in that the track curvature of the inner ring is smaller than 51.5% and greater than 50% of the ball diameter, and the track curvature of the outer ring is smaller than 52.5% and greater than 50% of the ball diameter. apparatus.   The differential device according to claim 1, wherein the contact angle is set in a range of 15 ° to 20 °.

Images