JPH084879A - Parallel shaft differential gear device - Google Patents

Abstract

PURPOSE:To differentiate a torque rate to be transmitted to one vehicle shaft when the other shaft is idly rotated, in a drive mode from a coast mode. CONSTITUTION:Twisting directions of side gears 20, 30 are oppositely set. Thrust washers 70L, 70C, 70R are respectively arranged between the side gear 20 and a housing 20, between he side gears 20 and 30, between the side gear 30 and a lid 60, respectively. A belleville spring 80L is arranged between the housing 10 and the thrust washer 70L for energizing the side gear 20 to the side of the side gear 30. A belleville spring 80R is arranged between the lid 60 and the side gear 30R for energizing the side gear 30 to the side of the side gear 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential gear device in which a preload is applied to a side gear so that torque can be transmitted to one output shaft even if one output shaft idles. In particular, it relates to a parallel shaft differential gear device in which a side gear and an element gear are parallel to each other.

[0002]

2. Description of the Related Art Generally, in a differential gear device, when one output shaft idles, torque cannot be transmitted to the other output shaft. Therefore, if the wheels connected to one of the output shafts lose their wheels, there is a problem that the state cannot be escaped.

In order to solve such a problem, in the differential gear device disclosed in Japanese Patent Laid-Open No. 2-66341, as shown in FIG. 8, side gears 1L and 1R are provided with springs (not shown). The power, that is, the preload F _SP is applied in advance. When such a preload F _SP is applied, the side gears 1L and 1R and the thrust washer 2 are
Since frictional resistance occurs between L, 2C, and 2R, torque can be transmitted to the other wheel even when one output shaft is idling.

[0004]

By the way, in the differential gear device, the torque amount that can be transmitted to the other output shaft when one output shaft idles is set in the drive mode as in a normal forward drive. There is a demand to make a difference between the time and the coast mode (the state in which the side gear and the element gear are engaged with each other by the tooth surface different from that in the drive mode) such as the time of reverse or engine brake operation. However, there is a problem that the above-mentioned differential gear device cannot meet such a demand.

That is, the differential gear device described in the above publication is a so-called orthogonal shaft type in which the axes of the side gear 1 and the element gear (not shown) are at right angles.
In such an orthogonal shaft type differential gear device, the side gears 1L and 1R must be twisted in the same direction in order to generate a differential. Side gear 1L,
If the torsional directions of 1R are the same, the thrust forces generated in the side gears 1L and 1R by meshing with the element gears are directed in the same direction. Of course, the thrust force generated in the drive mode and the thrust force generated in the coast mode are in opposite directions.

Assuming that the thrust force generated in the drive mode is F _D and the thrust force generated in the coast mode is F _C , the thrust force (F _SP + 2F _D ) acts on the thrust washer 2L in the drive mode to cause the thrust. Thrust force (F _SP + F _D ) acts on the washer 2C,
Thrust force F _SP acts on thrust washer 2R. Therefore, the total thrust force acting on all the thrust washers 2L, 2C, 2R is (3F _SP + 3F _D ).
Similarly, in coast mode, all thrust washers 2L,
The total thrust force acting on 2C and 2R is (3F _SP +
3F _C ). Here, since F _D and F _C have opposite directions and the same size, all thrust washers 2L, 2C, 2R
The thrust force acting on is the same in the drive mode and the coast mode. Therefore, when one output shaft idles, the torque transmitted to the other output shaft becomes equal in the drive mode and the coast mode, and a difference cannot be generated.

If the side gears 1L and 1R are twisted in the same direction, there is a difference in torque distribution ratio transmitted to the two output shafts when the vehicle turns right and when it turns left. There was a problem that is caused.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a rotationally driven housing and a torsion tooth supported by the housing with its axis aligned with the axis of the housing. A pair of side gears,
The housing is rotatably supported with its axis parallel to the axis of the housing, meshes with the pair of side gears, respectively, and at least a pair of element gears meshing with each other, between the end faces of the pair of side gears, and /
Alternatively, in a parallel shaft differential gear device including a thrust washer provided between the end faces of the pair of side gears and the housing, the twisting directions of the pair of side gears are opposite to each other, and the pair of side gears are in the axial direction. It is characterized in that elastic members for urging the two are mutually opposite. In this case, the elastic member may be arranged between the housing and the pair of side gears, or may be arranged between the pair of side gears. Further, when the elastic member is arranged between the housing and the pair of side gears, the direction in which each elastic member biases the side gear and the direction of the thrust force generated in the side gear during the drive mode are the same. When the elastic member is arranged between the pair of side gears, it is preferable that the direction in which the elastic member urges each side gear and the direction of the thrust force generated in each side gear are opposite to each other.

[0009]

The urging force of the elastic member and the thrust force generated in the side gear due to the meshing of the side gear and the element gear cancel each other out in one of the drive mode and the coast mode, and are added in the other. Therefore, a difference occurs in the frictional resistance acting on the thrust washer. As a result, when one output shaft idles, a difference occurs in the amount of torque transmitted to the other output shaft between the drive mode and the coast mode. Further, since the twisting directions of the pair of side gears are opposite to each other, the torque distribution ratio is the same regardless of whether the vehicle is turned left or right.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to. 1 and 2 show a parallel shaft differential gear device A according to the present invention, and the basic structure of the differential gear device A is the same as the conventional one.
Therefore, the basic structure will be briefly described. The differential gear device A includes a housing 10 and a pair of side gears 2.
0, 30, and three pairs of element gears 40, 50.

The housing 10 has a cylindrical shape, and a lid 60 is provided at the opening thereof. Also,
The housing 10 has a flange portion 1 at the end opposite to the opening.
1 is formed, and a ring gear (not shown) is fixed to the flange portion 11. This ring gear is rotationally driven by the engine, which causes the housing 1
0 is driven to rotate about its axis L.

Inside the housing 10, the side gear 2
0 and 30 are rotatably provided with their axes aligned with the axis L. The side gears 20 and 30 have teeth 2 having teeth that are twisted in opposite directions and at the same angle.
1 and 31 respectively. Also, the side gear 2
One ends of axles (output shafts) rotatably supported by the journal portion 12 of the housing 10 and the journal portion 61 of the lid body 60 are non-rotatably connected to the shafts 0 and 30 by spline fitting or the like. .

Inside the housing 10, three pairs of element gears 40 and 50 are rotatably supported.
The axis of each pair of element gears 40 and 50 is the axis L.
And are arranged at equal intervals around the side gears 20 and 30. Each element gear 40, 50
Has a long gear portion 41, 51 and a short gear portion 42, 52 at both ends. One element gear 40
The long gear portion 41 (51) of (50) meshes with one side gear 20 (30) and also meshes with the short gear portion 51 (41) of the other element gear 50 (40).

Between the housing 10 and the side gear 20,
Between the side gears 20 and 30, and between the side gear 30 and the lid 60, thrust washers 70L, 70C,
70R are arranged respectively. Thrust washer 7
In 0L and 70R, the contact surface with the side gears 20 and 30 is a sliding surface. On the other hand, the thrust washer 70C has the same frictional resistance on both end faces, and which end face is the sliding face differs depending on the time.

Although the above-described structure is similar to that of the conventional differential gear device, the differential gear device A further includes two disc springs (elastic members) 80L and 80R. One of the disc springs 80L is arranged between the housing 10 and the thrust washer 70L, and urges the side gear 20 toward the side gear 30 side via the thrust washer 70L.
The other disc spring 80R includes a lid 60 and a thrust washer 7.
It is located between 0R and thrust washer 70R.
The side gear 30 is urged to the side gear 20 side via. In this embodiment, two disc springs 80L, 80
Although the biasing forces of R (hereinafter referred to as preload) are the same, they may have different sizes.

In the differential gear device A having the above structure, the housing 10, the element gears 40 and 50, and the side gears 20 and 30 rotate integrally during normal forward travel (straight travel). The drive torque transmitted from the ring gear to the housing 10 is transmitted to the side gears 20 and 30 via the element gears 40 and 50, and further transmitted to the axle. When the vehicle turns, the element gear 40,
By rotating 50, one side gear 20 (3
0) rotates at a high speed with respect to the housing 10, and the other side gear 30 (20) rotates at a low speed with respect to the housing 10, so that a differential is generated.

In the differential gear unit A, when the axle connected to one of the side gears 20 (30) idles, the side gears 20 (30) and the thrust washer 70
L (70R) is brought into pressure contact with the preload, and when they rotate relative to each other, torque due to frictional resistance is generated. This torque is transmitted to the other side gear 30 (20) via the housing 10. Therefore, even if one axle spins, torque can be transmitted to the other axle.

Further, according to this differential gear device A, the torque amount transmitted to the other axle when one axle spins can be made different between the drive mode and the coast mode. it can. That is, the side gear 2
Thrust force is generated at 0 and 30 by meshing with the element gears 40 and 50. Now, as shown in FIG. 3, let F _{D be} the thrust force in the drive mode and F _{C be} the thrust force in the coast mode. Also, the thrust force F _D
Is the same as the urging direction of the disc spring 70L (70R) that urges the side gear 20 (30).

Under these conditions, the thrust force acting on each thrust washer 70L, 70R, 70C is calculated. In the drive mode, the thrust washer 70L, 70L
Thrust force F _SP acts on 70R and thrust washer 7
Thrust force (F _SP + F _D ) acts on 0C. On the other hand, in coast mode, thrust washers 70L, 70R
Thrust force F _SP acts, the thrust force on the thrust washer 70C (F _SP -F _C) acts on. Here, for convenience of explanation, if the thrust forces F _D , F _C are equal to the preload F _SP , the total thrust force acting on all the thrust washers 70L, 70R, 70C is 4F _SP in the drive mode. On the other hand, 2F _{SP in} coast mode
become. In this way, all thrust washers 70L, 70
Since the thrust force acting on the R and 70C is different between the drive mode and the coast mode, the total torque transmitted to both axles (hereinafter referred to as the total torque) is accordingly different between the drive mode and the coast mode. And will be different. Of course, in the above case, the total torque amount in the drive mode becomes larger than the total torque amount in the coast mode. Here, when one axle slips,
The amount of torque transmitted to the other at that time is the total amount of torque. Therefore, the amount of torque transmitted to the other axle when one axle is idling is greater in the drive mode than in the coast mode.

FIG. 4 shows the total torque amount T _S in the drive mode and the coast mode of the differential gear device A as a function of the torque amount T _L transmitted to the low μ (low friction resistance) side axle. The solid line indicated by D in the figure is the total torque in the drive mode, and the solid line indicated by C is the total torque in the coast mode. In this figure, the total torque amount T _S when the torque T _L is zero is the torque amount transmitted to the other axle when one axle is idling, and the torque amount T _{S in the} drive mode is the coast mode. Is larger than the torque amount T _{S of} . In addition,
The slope of the total torque amount T _{S in} the coast mode changes at the point α because the thrust force F _{C in the} coast mode is F.
_This is because when it becomes larger than _SP , the thrust washer 70C does not participate in the transmission torque, and the characteristics are the same as those without preload. Also, the broken lines indicated by D and C in the figure respectively show the total torque T _S in the drive mode and the coast mode when the preload is not applied.

Also, since the side gears 20 and 30 are twisted in opposite directions, when the vehicle turns right or left,
That is, transmission is transmitted to both axles when one side gear 20 (30) rotates faster than the other side gear 30 (20) and when the other side gear 30 (20) rotates faster than one side gear 20 (30). The torque distribution ratios can be the same.

Next, another embodiment of the present invention shown in FIG. 5 will be described. In the differential gear device B of this embodiment, two thrust washers 70C _L and 70C are used instead of the thrust washer 70C. _R is used.
Also, disc springs 80L of the above embodiments, and the disc spring 80C is used in place of 80R, the disc spring 80C, the two thrust washers 70C _L, is disposed between the 70C _R. Then, as shown in FIG. 6, the disc spring 80C presses the side gear 20 in the direction opposite to the thrust force F _D via the thrust washer 70C _L , and the thrust washer 70C _R
The side gear 30 is pressed in the direction opposite to the thrust force F _D via.

In the differential gear device constructed as described above, assuming that the preload F _SP and the thrust forces F _D and F _C are F _SP = F _D = F _C , as in the above-described embodiment, all of them are assumed. The total thrust force acting on the thrust washers 70L, 70R, 70C _L , 70C _R is 2F _{SP in the} drive mode.
And becomes 6F _SP in coast mode. Therefore, when the torque amount T _L transmitted to one axle is zero, the torque amount (T _S ) transmitted to the other axle is larger in the coast mode than in the drive mode.

However, the above contents are conceptual,
In fact, as is clear from FIG. 7, the total torque amount line C in the coast mode is a parallel displacement of the total torque amount line C ′ when the preload is not applied to the side where the total torque amount increases. Accordingly, the total torque amount line D in the drive mode is a line in which the slope of the total torque amount line D ′ when the preload is not applied becomes smaller in the range of T _L <β. As a result,
T _L = 0 torque amount T _S coast mode in the case where, although larger than the torque amount T _S during the drive mode, T _L> torque amount T _S during the drive mode in the range of γ is coasting mode Is greater than the total torque of.

In the above-described embodiment in which the total torque amount T _S changes in the drive mode and the coast mode as described above, the vehicle body gradually moves inside the circle during the deceleration circle turning with the accelerator pedal released. It is possible to reduce the so-called tuck-in phenomenon that is involved.

The present invention is not limited to the above embodiment, but can be modified as appropriate. For example, although three pairs of element gears are provided in the above embodiment, at least one pair may be provided. Further, in each of the above-described embodiments, the side gear 20,
Although the thrust force F _D that is closer to 30 to each other is configured to generate, it may be configured to thrust force F _D in the opposite direction is generated from this.

[0027]

As described above, according to the parallel shaft differential gear device of the present invention, it is of course possible to transmit torque to the other axle even when one output shaft idles. Therefore, the torque transmission amount during idling can be made different between the drive mode and the coast mode. Further, it is possible to prevent a difference in torque distribution ratio from occurring when turning left and right.

[Brief description of drawings]

FIG. 1 is a sectional view taken along line XX of FIG. 2 showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line YY of FIG.

FIG. 3 is a diagram showing a pair of side gears, a thrust washer, and thrust forces acting on them in the embodiment shown in FIGS. 1 and 2.

FIG. 4 is a diagram showing the relationship between the amount of torque transmitted to the axle with the smaller frictional resistance and the total amount of torque transmitted to the two axles in the embodiment shown in FIGS. 1 and 2.

FIG. 5 is a half sectional view showing another embodiment of the present invention.

FIG. 6 is a diagram showing a pair of side gears, a thrust washer, and a thrust force acting on them in the embodiment shown in FIG.

FIG. 7 is a diagram showing a relationship between a torque amount transmitted to an axle having a smaller frictional resistance and a total torque amount transmitted to two axles in the embodiment shown in FIG.

FIG. 8 is a diagram showing a pair of side gears, a thrust washer, and a thrust force that acts on them in a conventional orthogonal shaft differential gear device.

[Explanation of symbols]

A Parallel shaft differential gear device B Parallel shaft differential gear device 10 Housing 20 Side gear 30 Side gear 40 Element gear 50 Element gear 70C Thrust washer 70C _L Thrust washer 70C _R Thrust washer 70L Thrust washer 70R Thrust washer 80L Disc spring 80R Disc spring Disc spring

 ─────────────────────────────────────────────────── ───Continued from the front page (72) Inventor Sandro Guidoni Larvie Park Industriel de Strippy Blackneys Roux de Grand Puplet 11 Zexel Torsen Es. A. Within

Claims (5)

[Claims] 1. A housing driven to rotate, a pair of side gears having torsion teeth supported by the housing with its axis aligned with the axis of the housing, and rotatably with the axis parallel to the axis of the housing. Is supported and meshes with the pair of side gears, respectively,
A parallel shaft differential gear device including at least a pair of element gears meshing with each other, and a thrust washer provided between the end faces of the pair of side gears and / or between the end faces of the pair of side gears and the housing,
The twisting directions of the pair of side gears are opposite to each other,
A parallel shaft differential gear device comprising elastic members for urging the pair of side gears in opposite axial directions. 2. The parallel shaft differential gear device according to claim 1, wherein the elastic member is arranged between each of the housing and the pair of side gears. 3. The direction in which the elastic member biases each side gear and the direction of the thrust force generated in each side gear in the drive mode due to meshing with the element gear are the same. The parallel shaft differential gear device according to. 4. The parallel shaft differential gear device according to claim 1, wherein the elastic member is arranged between the pair of side gears. 5. The direction in which the elastic member urges each side gear and the direction of the thrust force generated in each side gear in the drive mode due to the meshing with the element gear are opposite to each other. 4. The parallel shaft differential gear device according to item 4.