JPH044345A - Differential limitting device - Google Patents

Abstract

PURPOSE:To restrict the rotation of a pinion gear by means of sliding frictional force caused by tapered roller bearing, and thereby restrict differential movement between paired drive shafts by intersecting the extension of a generating line of an outer ring raceway surface with the extension of the generating line of an inner ring raceway surface at a position isolated from the axial center of the bearing in a plane including the axial center of the tapered roller bearing. CONSTITUTION:In a plane including the bearing axial center alpha of a tapered roller bearing 9, the extension 7 of the generating line of an outer ring raceway surface 93a is intersected with the extension gamma of the generating line of an inner ring raceway surface 91a at a position A isolated from the bearing axial center alpha. By this constitu tion, a tapered roller 10a is rotated while its inclination is being restricted, the circum ferential surface of the tapered roller 10a and each raceway surface 19a and 93a are thereby mutually slid, so that frictional force is caused between them. Frictional force is also caused between the end face of the tapered roller 10a and a collar section. In this case, the aforesaid sliding frictional resistance is turned out to be the rotational resistance of the tapered roller bearing 9, so that the rotation of a pinion gear is thereby restricted. By this constitution, differential movement between paired drive shafts connected to each side gear is thereby restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a differential limiting device incorporated in a differential interposed between the front and rear wheel drive shafts or between the left and right wheel drive shafts of an automobile.

<Prior Art> When an automobile is cornering, wheels on the inside of the turn and wheels on the outside of the turn draw circles with different radii.

A differential is a device that allows for this difference in rotation between the inner and outer wheels to ensure smooth cornering.

This differential generally has two pairs of four bevel gears housed in a gear case that rotates in conjunction with the engine. A pair of opposing bevel gears are called side gears, and are connected to the left and right axles so as to be able to rotate integrally with each other.

The remaining pair of bevel gears are called pinion gears. Referring to FIG. 9, the pinion gear 6o is connected to a pinion shaft 61 installed in a gear case (not shown).
It is rotatably supported.

In the above differential, if the left and right wheels receive the same resistance from the road surface, the side gear and pinion gear rotate integrally with the gear case without relative rotation, and if the resistance of either the left or right axle increases. teeth,
When the pinion gear rotates, a differential rotation is generated between the pair of side gears, and the axle on the side with increased resistance is decelerated, and the axle on the side with less resistance is accelerated by the amount of this deceleration.

The above-mentioned differential has the advantage of making the vehicle corner smoothly, but if one wheel slips due to a wheel derailment, etc., only that one wheel will rotate, and the other wheel will stop rotating. There was a problem with putting it away.

In order to solve these problems, many differentials have been provided in which a differential limiting device such as a friction clutch or a viscous coupling is incorporated into the differential.

<Problems to be Solved by the Invention> However, these differential limiting devices have a complicated structure and have the disadvantage of increasing the weight of the differential.

On the other hand, with the spread of four-wheel drive vehicles in recent years, a differential called a center differential that allows differential movement between the front and rear wheels has also been provided, and the differential limiting device attached to this center differential also has a similar There was a problem.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a differential limiting device that has a simple structure and is lightweight.

<Means for Solving the Problems> In order to achieve the above object, the differential limiting device according to the present invention includes a pair of drive shafts that rotate in conjunction with a pair of drive shafts in a gear case that rotates in conjunction with the engine side. A differential limiting device for limiting the differential movement of the pair of drive shafts, which is incorporated in a differential including a side gear consisting of opposing bevel gears, and a pinion gear consisting of a pair of opposing bevel gears meshing with both side gears, Each of the above pinion gears is attached to a pinion shaft fixed to the gear case.
Consisting of a tapered roller bearing that is rotatably supported, in a plane that includes the bearing axis of this tapered roller bearing, an extension of the generatrix of the outer ring raceway surface and an extension of the generatrix of the inner ring raceway surface are aligned with the bearing axis. It is characterized by having an intersection point at a position separated from the top.

<Operation> According to the differential limiting device configured as described above, in a plane including the bearing axis of the tapered roller bearing, the extension line of the generatrix of the outer ring raceway surface and the extension line of the generatrix of the inner ring raceway surface are Assuming that the tapered rollers have ideal rolling contact with the outer ring raceway surface and the inner ring raceway surface because the intersection points are located at a distance from the axis, the rolling axis of the tapered rollers can be determined based on the principle of the invention below. A force acts to tilt the heart to a torsional position with respect to the bearing axis.

However, the position of the tapered rollers is regulated by the outer ring raceway surface, the inner ring raceway surface, and the flange of the inner ring.

Therefore, the tapered roller moves while its inclination is regulated, and sliding occurs between the circumferential surface of the tapered roller and the raceway surface, resulting in sliding friction. There is also sliding friction between the end face of the tapered roller and the flange.

These sliding frictional resistances act as rotational resistance of the tapered roller bearing, and the rotation of the pinion gear is restricted. When the rotation of the pinion gear is restricted, the differential between the pair of side gears is restricted, and the differential between the pair of drive shafts connected to each side gear is restricted.

Principle of the Invention Fig. 1 shows that the intersection point A of the extension line γ of the generatrix of the inner ring raceway surface 91a made of a conical surface and the extension line η of the generatrix of the outer ring raceway surface 93a made of a cone surface is at a distance from the bearing axis α. This shows the case where they are located at a distance of l.

In the same figure, the contact point between the large-diameter side end surface 10c of the tapered roller 10a and the generatrix of the inner ring raceway surface 91a is B1 large-diameter side end surface 10.
d and the generatrix of the outer ring raceway surface 93a is C1, the contact point between the small diameter end surface 10d and the generatrix of the inner ring raceway surface 91a is D, and the contact point between the small diameter end surface 10d and the generatrix of the outer ring raceway surface 93a is E. The intersections of the perpendicular lines drawn from point B and the dot to the bearing axis α and the bearing axis α are points F and G, respectively, and the lengths of the perpendicular line BF and perpendicular line DG are b and d, respectively. .

Also, the diameter (B
C), the diameter (DE) of the R1 small diameter side end surface 10d is r. Further, suppose an imaginary line m passing through the intersection A and parallel to the bearing axis α, and let the intersections of the imaginary line m and extensions of the perpendicular line BF and the perpendicular line DG be a point H and a point I, respectively.

The tapered rollers 10a make ideal rolling contact, and the large diameter side of the tapered rollers 10a rolls around the inner ring raceway surface 91a.
Assuming one revolution, the circumference of the large diameter side is 2πb
Therefore, on the large diameter side, 2πb/πR=2b
/R rotation. With this 2b/R rotation, the circumference of the small diameter side is (2b / R) X yr r = 2 yr b
This means that it has advanced by r/R■.

Here, since triangle ABC and triangle ADE are similar, AD/AB=DE/BC■ Also, since triangle ABH and triangle ADI are similar, AD/AB=DI/BH■ Therefore, the formula■ And from the formula ■, DE/BC=DI/BH - (DG10'l)/ (BP10FH), that is, r/R-(d+A)/ (b+A) ■This formula■
Therefore, the right side of formula
), and if the difference Δ between this and 2πd is 0, the small diameter side will also make one revolution in one revolution on the large diameter side, but Δ=2πb
(d+A)/(b+A)-2πd=2πA (b-
d)/(b+A), and since the inner ring raceway surface 91a is a conical surface, 2π(b-d)/(b-11?) is not 0.

Therefore, if l>0, Δ>0, and while the large diameter side makes one revolution, the small diameter side makes one revolution or more. ), and move toward the small diameter side or the large diameter side.
The rolling axis β of the tapered rollers 10b is inclined to a twisted position with respect to the bearing axis α.

Also, if l<0, then ∆ is 0, which means that the small diameter side cannot make one revolution while the large diameter side makes one revolution. ), so that the small diameter side lags behind the large diameter side.
The rolling axis β of the tapered rollers 10a is inclined to a twisted position with respect to the bearing axis α.

<Example> Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments.

FIG. 5 shows a differential including a differential limiting device as an embodiment of this invention.
A gear case 4 that is attached to a ring gear 3 that meshes with a drive pinion 2 that rotates in conjunction with the side (not shown) and rotates integrally with the ring gear 3; A pair of side gears 5a, 5b are spline-coupled to the wheel axle 7a and the right rear wheel axle 7b, respectively, and a pair of pinion gears 6a, 6b meshed with both side gears 5a, 5b, respectively.

Inside the differential l is a pinion gear 6a.

A pair of tapered roller bearings 9 are incorporated as a differential limiting device that limits the differential movement between the left rear wheel shaft 7a and the right rear wheel shaft 7b by restricting the rotation of the wheel 6b.

The side gear 5a rotates integrally with the left rear wheel shaft 7a, and the side gear 5b rotates integrally with the right rear wheel shaft 7b.

The tapered roller bearing 9 includes a pinion shaft 8 fixed in the gear case 4 and each pinion gear 6 along a direction perpendicular to the rotation axis of the slide gears 5a and 5b.
a, 6b, and the pinion gears 6a, 6b
is rotatably supported by the pinion shaft 8.

Referring to FIG. 4, the tapered roller bearing 9 includes a pair of inner rings 91, 92 fitted onto the pinion shaft 8, an outer ring 93 fitted inside the inner diameter portions of the slide gears 5a, 5b, and each inner ring 91. It consists of two rows of tapered rollers 10a and 10b interposed between 92 and outer ring 93. The inner ring 91 has a flange 91.
b, 91c are formed, and each of the collar portions 91b, 91c abuts on the large-diameter end surface 10c and the small-diameter end surface 10d of the tapered roller 10a, respectively, to regulate the inclination of the tapered roller 10a within a predetermined range. Regarding the inner ring 92, collar portions 92b and 92c are similarly formed.

Inner ring raceway surface 91a formed on the outer periphery of each inner ring 91,92
, 92a are formed into conical surfaces inclined in opposite directions. The inner periphery of the outer ring 93 has the above-mentioned inner ring raceway surface 91a.
, 92a, a pair of outer ring raceway surfaces 93a, 93b
or is formed.

With reference to FIG. 6, an extension line γ of the generatrix of the inner ring raceway surface 91a
The intersection point A between and the extension line η of the generatrix of the outer ring raceway surface 93a is
It is set at a position apart from the bearing axis α of the tapered roller bearing 9 (that is, the rotational axis of the pinion shaft 8).

The same applies to the intersection of the extension line of the generatrix of the inner ring raceway surface 91b and the extension line of the generatrix of the outer ring raceway surface 93b (not shown).

According to this embodiment, since the extension line γ of the generatrix of the inner ring raceway surface 91a and the extension line η of the generatrix of the outer ring raceway surface 93a have an intersection A at a position apart from the bearing axis α, the inner ring raceway Assuming that the tapered rollers 10a make ideal rolling contact with the surface 9]a, based on the principle of the invention described above, the rolling axis of the tapered rollers IOa is torsionally adjusted relative to the bearing axis α. A force acts to tilt the object into position.

Due to this force, the rolling axis β of the tapered roller IOa tends to tilt, but the tapered roller 10a
Since the position of the tapered roller]Oa is regulated by the outer raceway surface 93a and the flanges 91b and 91c, the tapered roller]Oa rolls while its inclination is regulated, and the tapered roller]Oa
Sliding occurs between the circumferential surface of the inner ring raceway surface 91a and the outer ring raceway surface 93a, and sliding friction occurs. Further, sliding friction also occurs between the large-diameter end surface 10c of the tapered roller 10a and the flange 91b, and between the small-diameter end surface 10d and the flange 91c. Due to these edge frictional resistances, the tapered roller 1
Rotation of 0a is restricted. The rotation of the tapered roller lOb is similarly restricted.

Therefore, the rotation of the tapered roller bearing 9 is restricted, and the rotation of the pinion gear 6a is restricted. The rotation of pinion gear 6b is similarly restricted.

In the differential, when the left rear wheel shaft 7a and the right rear wheel shaft 7b are rotating at the same speed, the pinion gears 6a and 6b are not rotating, but the left rear wheel shaft 7b is rotating at the same speed.
When a differential rotation occurs between a and the right rear wheel shaft 7b, the pinion gears 6a and 6b rotate. However, since the rotation of the pinion gears 6a, 6b is limited by the sliding friction generated in the tapered roller bearing 9, the differential movement between the pair of side gears 5a, 5b is limited, and each side gear 5a
, 5b is restricted. This differential limiting device is composed of a tapered roller bearing 9 installed between the pinion gears 6a, 6b and the pinion shaft 8 in the differential 1, so compared to a conventional friction clutch or viscous coupling, The structure is very simple and does not increase the weight of the differential.

In the above embodiment, a double-row tapered roller bearing is used, but a single-row tapered roller bearing can also be used.

Further, as shown in FIG. 7 or 8, the end surface 6c of the pinion gear 6a and the end surface 93b of the outer ring 93 are brought into contact with the flange portion 8a provided on the pinion shaft 8, and the frictional resistance force due to this contact is It can also be added to the sliding friction resistance force.

Furthermore, the present invention is not limited to the above-mentioned embodiments; for example, the outer ring and the pinion gear may be integrally configured, and the present invention may also be applied to a center differential. Various design changes can be made without changing the gist of the invention.

In addition, since the tapered roller bearing used in the present invention utilizes the frictional resistance force due to the heel, the wear of the inner ring raceway surface, the outer ring raceway surface, and the mutual contact parts of the tapered rollers, or the wear that is larger than that of a normal tapered roller bearing. However, by using a material with high wear resistance as the bearing material, the occurrence of the above wear can be suppressed.

For example, it is desirable to use ceramic materials or high-hardness metal materials such as high-speed steel for both the inner and outer rings and the tapered rollers, or the tapered rollers are made of ceramics and the inner ring flange is made of ceramic material. A ceramic coating may be applied to the contact surface with the tapered roller.

Furthermore, it is preferable to use a material with excellent wear resistance as the lubricating material itself.

Of course, a bearing ring with high hardness and wear resistance may be obtained by appropriately selecting the heat treatment conditions, heat treatment method, etc. of the bearing.

<Effects of the Invention> As described above, according to the present invention, the rotation of the pinion gear can be restricted by the sliding friction force generated in the tapered roller bearing or the rotational resistance of the tapered roller bearing. By limiting the differential movement between the side gears, it is possible to limit the differential movement between the pair of drive shafts connected to each side gear. Since this differential limiting device is composed of a tapered roller bearing that limits the rotation of the pinion gear, it has a simple structure and has the unique effect of not causing an increase in the weight of the differential.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view showing the principle of the present invention, Figs. 2 and 3 are plan views thereof, and Fig. 4 shows a tapered roller bearing as a differential limiting device according to an embodiment of the present invention, which is connected to a pinion gear. 5 is a schematic sectional view of the differential, FIG. 6 is a sectional view of the tapered roller bearing, and FIGS. 7 and 8 are respectively illustrative of other embodiments of the differential limiting device. Cross-sectional view FIG. 9 is a cross-sectional view showing how a conventional pinion gear is installed. 1...Differential, 4...Gear case, 5a
, 5b...Side gear, 6a, 6b... Pinion gear, 8... Pinion shaft, 9... Tapered roller bearing (differential limiting device), Lla, 9
2a... Inner ring raceway surface, 93a... Outer ring raceway surface, 10a, fob... Tapered roller, γ... Extension line of generatrix of inner ring raceway surface, η... Extension line of generatrix of outer ring raceway surface , A...Intersection, α...Bearing axis, β...Rolling axis.

Claims (1)

[Claims] 1. Inside the gear case that rotates in conjunction with the engine side, there is a side gear consisting of a pair of opposing bevel gears that rotates in conjunction with a pair of drive shafts, and a pinion gear consisting of a pair of opposing bevel gears that mesh with both side gears. In the differential limiting device that is incorporated in a differential having
Consisting of a tapered roller bearing that is rotatably supported, in a plane that includes the bearing axis of this tapered roller bearing, an extension of the generatrix of the outer ring raceway surface and an extension of the generatrix of the inner ring raceway surface are aligned with the bearing axis. A differential limiting device characterized by having an intersection point at a position spaced apart from above.