JPH05187487A - Planetary gear type differential device - Google Patents

Abstract

PURPOSE:To prevent power loss and the lowering of fuel consumption by providing a rotating section between the first or the second planetary gear and a carrier with a differential restricting means, and moreover providing that means with a friction clutch and a pressurized spring to give proper fastening force to the clutch. CONSTITUTION:Driving force inputted into a differential case 3 drives the first and the second planetary gears 13, 15 from an internal gear 9, the right wheel from the right carrier 23 through the right hub 7, and the left wheel from a sun gear 11 through the left hub 5. When a difference in driving resistance occurs between the right and left wheels, the autorotation and revolution of the planetary gears 13, 15 differentially distribute the driving force to the right and left wheels. In this case, the rotation of the planetary gears 13, 15 is braked by the frictional torque of a rotating section, and as transmitted torque is larger, the frictional torque becomes larger to strengthen differential restricting force. On the other hand, a disc spring 33 between the right carrier 23 and the differential case 3 always presses a cone clutch 31 to give it proper initial torque for producing proper differential restricting force irrespective of the size of the transmitted torque and the number of revolutions. Thus power loss can be reduced, and fuel consumption can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary gear type differential device used in a drive system of a vehicle.

[0002]

2. Description of the Related Art Conventionally, a differential gear utilizing a planetary gear mechanism is well known, and its typical structure is an internal gear fixed to a driven gear and a differential case, and coaxial with the internal gear. A sun gear rotatably arranged with respect to the differential case, a first planetary gear that meshes with the internal gear, and a second planetary gear that meshes with the first planetary gear and also meshes with the sun gear.
The planetary gears and a carrier that rotatably supports the first and second planetary gears and is itself rotatably arranged with respect to the differential case. The shaft is connected to a left axle, and the carrier is connected to the other drive shaft such as a right axle.

In such a mechanism, when a rotational force is applied to the differential case through the driven gear, the internal gear integrally connected to the differential case rotates, and the rotational force is transmitted through the first and second planetary gears. Is transmitted to the sun gear and the carrier, and rotationally drives the left axle connected to the sun gear and the right axle connected to the carrier.

However, there is a characteristic that when the left wheel slips and the driving torque of the left axle decreases due to the road surface condition or the like when the vehicle goes straight ahead, the driving torque of the right axle also decreases. In order to improve this characteristic, by braking the relative rotation between the internal gear and the carrier or the relative rotation between the internal gear and the sun gear, the left axle connected to the sun gear and the right axle connected to the carrier are conventionally braked. An invention has been made in which the differential rotation between and is prevented so as to prevent the driving torque of the anti-slip side axle from significantly lowering (see Japanese Patent Laid-Open No. 61-96238 and Japanese Utility Model Laid-Open No. 1-161657).

[0005]

However, as seen in the drawings of the above publications, in order to brake the relative rotation between the internal gear and the carrier or between the internal gear and the sun gear, a multi-plate type is used. A friction clutch mechanism and the like are provided. These are configured to engage a multi-plate friction clutch with a hydraulic actuator or an electromagnet. In any case, in such a configuration, an oil pump, an alternator for charging a battery, etc. must be driven by the engine. Without that, fuel consumption is reduced with power loss. When using a hydraulic actuator, the hydraulic circuit complicates the structure and transmits and receives the pressing force between the stationary hydraulic actuator located outside the rotating differential case and the multi-plate friction clutch located inside the differential case. Mechanism is required, which further complicates the structure. Further, when an electromagnet is used, a magnetic leakage prevention structure for forming a magnetic circuit is necessary, and adjustment of the air gap between the differential case and the electromagnet is troublesome.

Therefore, the present invention provides a planetary gear type differential device which can obtain a differential limiting force without causing power loss of an engine and reduction of fuel consumption, is easy to handle, and is small-sized, lightweight and simple in structure. To aim.

[0007]

A planetary gear type differential device according to a first aspect of the present invention includes an internal gear fixed to a driven gear and a differential case, and coaxial with the internal gear and rotating with respect to the differential case. A freely arranged sun gear, a first planetary gear that meshes with the internal gear, a second planetary gear that meshes with the first planetary gear and also meshes with the sun gear, and A carrier that rotatably supports the first and second planetary gears and that is itself rotatably arranged with respect to the differential case, and connects the sun gear to one drive shaft, Is a planetary gear type differential device which is connected to the other drive shaft, the differential limiting device being provided in a rotating portion between the carrier and the first planetary gear and / or the second planetary gear. , Friction clutch for limiting the differential and suitable for this Characterized in that a preload spring providing a fastening force.

The planetary gear type differential device of the second invention is provided with an internal gear fixed to the driven gear and the differential case, and arranged coaxially with the internal gear and rotatable with respect to the differential case. A sun gear, a first planetary gear that meshes with the internal gear, a second planetary gear that meshes with the first planetary gear and also meshes with the sun gear, and the first and second planetary gears Each of the gears is rotatably supported, and the carrier itself is rotatably disposed with respect to the differential case.The sun gear is connected to one drive shaft, and the carrier is connected to the other drive shaft. A planetary gear type differential device connected to each other, wherein a meshing back gap between the internal gear and the first planetary gear, a meshing back gap between the first planetary gear and the second planetary gear, and Out of the meshing back clearance between the second planetary gear and the sun gear With Izure or very small amount of at least one meshing backlash, characterized by comprising a preload spring for providing a frictional clutch and moderate tightening force thereto for differential limiting.

The planetary gear type differential device of the third invention is provided with an internal gear fixed to the driven gear and the differential case, and arranged coaxially with the internal gear and rotatable with respect to the differential case. A sun gear, a first planetary gear that meshes with the internal gear, a second planetary gear that meshes with the first planetary gear and also meshes with the sun gear, and the first and second planetary gears Each of the gears is rotatably supported, and the carrier itself is rotatably disposed with respect to the differential case.The sun gear is connected to one drive shaft, and the carrier is connected to the other drive shaft. A planetary gear type differential device connected to the second planetary gear, wherein the second planetary gear is arranged rearward of the first planetary gear with respect to a forward drive direction of the internal gear, and is for limiting the differential. The friction clutch and its proper fastening force Characterized by comprising a preload spring that.

[0010]

When the output from the engine of the vehicle is transmitted to the driven gear through the transmission, the output gear, etc., the differential case and the internal gear integrated with the driven gear are rotationally driven, and the straight traveling on a good road surface is performed. When, for example, the differential case and the internal gear, the first
The second planetary gear, the sun gear, and the carrier are almost integrally rotated, and the driving torques of the left and right axles are substantially equal.

However, in the case where no differential limiting means is provided, if one wheel slips due to a road surface condition or the like and the drive torque of the slip side drive shaft decreases, the drive of the other drive shaft is driven. The torque also drops.

However, in the differential device according to claim 1 of the present application, the differential limiting means is provided in the rotating portion between the first planetary gear and / or the second planetary gear and the carrier. An appropriate friction torque is generated in the rotating portion, so that the drive torque is appropriately distributed between the one drive shaft and the other drive shaft.

Further, in the differential device according to claim 2 of the present application, each meshing back of the internal gear, the first planetary gear, the second planetary gear, and the sun gear that constitute the planetary gear set. At least one of the clearances has an extremely small meshing back clearance, so that an appropriate braking torque is generated in the relative rotation between the gears, which drives one drive shaft and the other drive shaft. The torque is distributed appropriately.

Further, in the differential device according to claim 3 of the present application, the second planetary gear is located rearward of the first planetary gear with respect to the forward drive direction of the internal gear, that is, the forward direction. Since it is arranged, when a differential rotation occurs between the left and right drive shafts during forward drive, from the relationship between the pressing force generated along the line of action including the meshing pitch points of the gears and their reaction force,
Appropriate braking is applied to the rotation of each planetary gear, and the drive torque is appropriately distributed between the left and right drive shafts.

Further, during reverse drive or during coasting, the rotation of each planetary gear is weakly braked as compared with during forward drive, and drive torque is appropriately distributed between the left and right drive shafts.

As described above, in addition to the differential limiting function in which a larger differential limiting force is obtained as the transmission torque and the rotational speed increase, each invention has a friction clutch to which an initial torque is given by a preload spring. Due to the braking force, an appropriate differential limiting force irrelevant to the transmission torque and the rotation speed can be obtained. Therefore, the running performance is kept high especially in the low speed range.

Further, unlike the conventional example, since the present invention does not use a hydraulic actuator or an electromagnet to obtain the differential limiting force, the fuel consumption of the engine does not decrease and the handling is simple and the size is small. Light weight and simple structure.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments in which the present invention is applied to a vehicle final reduction gear will be described below.

FIG. 1 is a longitudinal sectional view of a planetary gear type differential device 1 of an embodiment according to claim 1, and FIG. 2 is a transverse sectional view showing an arrangement state of respective movable members constituting a planetary gear set. The left and right directions are the left and right directions in FIG. 1, and members and the like without reference numerals are not shown.

A ring gear (driven gear) is fixed to the differential case 3. The ring gear meshes with the drive pinion gear on the propeller shaft side, and the differential case 3 is rotationally driven by the driving force of the engine via the transmission and the propeller shaft.

As shown in FIG. 1, left and right hubs 5 and 7 are arranged inside the differential case 3. The left hub 5 is splined to the drive axle on the left wheel side, and the right hub 7
Is spline-connected to the drive axle on the right wheel side so as to be movable in the axial direction. A planetary gear set is arranged inside the differential case 3. The internal gear 9 is formed on the differential case 3, and the sun gear 11 is formed on the left hub 5. Four sets of a first planetary gear 13 and a second planetary gear 15 (shown in FIG. 2) meshing with each other are arranged between them, and the planetary gear 13 meshes with the internal gear 9 and the planetary gear 15 Meshes with the sun gear 11.

These planetary gears 13 and 15 are rotatably supported on pins 17 and 19, respectively.
Both ends of 7, 19 are supported by the left and right carriers 21, 23. These carriers 21 and 23 are bridge portions 25.
And the right carrier 23 is integrally formed with the right hub 7. The degree of fitting of the rotating parts of the pins 17 and 19 and the planetary gears 13 and 15 is set more densely than in the prior art in order to generate friction torque. As a material for the rotating portion, it is preferable to use a material having high wear resistance, for example, a surface-hardened steel material.

Further, a spiral oil groove 27 is provided on the outer circumference of the pins 17 and 19, so that the thickness of the oil film formed on the rotating portion is controlled to control the magnitude of the friction torque. .. The differential case 3 is provided with an oil inflow hole and an oil outflow hole to lubricate the inside.

The first and / or second planetary gears 13,
Rotating portion between the carrier 15 and the carriers 21 and 23, that is, pins 17 and 1
The friction torque can also be increased by roughening the surface roughness of the outer peripheral surface of 9 and the inner peripheral surfaces of the circular holes of the planetary gears 13 and 15.

As shown in FIG. 1, a clutch member 29 is arranged on the left side of the planetary gear set and meshes with the sun gear 11 so as to be axially movable. A cone clutch 31 (friction clutch) is formed between the clutch member 29 and the left carrier 21. Further, a disc spring 33 (preload spring) is arranged between the right carrier 23 and the differential case 3, and constantly presses the cone clutch 31 to give an appropriate initial torque.

In this way, the planetary gear type differential device 1 is constructed.

The engine driving force input to the differential case 3 rotationally drives the right wheel from the internal gear 9 through the first and second planetary gears 13 and 15 and the right carrier 23 through the right hub 7 to drive the sun. The left wheel is rotationally driven from the gear 11 via the left hub 5. When a driving resistance difference occurs between the left and right wheels, the driving force of the engine is differentially distributed to the left and right wheels due to the rotation and revolution of each planetary gear 13, 15.

At this time, the rotation of the planetary gears 13 and 15 is braked by the friction torque of the rotating portion, and the differential limitation is performed. The friction torque increases as the transmission torque increases, and the differential limiting force is strengthened. On the other hand, cone clutch 3
In No. 1, an appropriate differential limiting force can be obtained by the initial torque irrespective of the transmission torque and the number of rotations.

The planetary gears 13, 15 and the pins 17,
19 and 19 are integrated respectively, and each carrier 2
The diameter of the rotating portion with respect to 1 and 23 may be increased. Further, for example, the carrier 21 side may be a large diameter portion and the carrier 23 side may be a small diameter portion. By thus increasing the diameter of the rotating portion, the friction torque can be further increased even with the same friction coefficient as that of the embodiment of FIG. In addition to this,
In the latter case, the first planetary gear 13 and the second planetary gear 15
This is advantageous when the distance between the shafts and is relatively short and the large-diameter shaft portions interfere with each other.

Also in these cases, it is preferable to use a material having a high wear resistance, for example, a surface-hardened steel material as the material of the relative rotating portion. Further, the friction torque can be further increased by making the surface roughness of the rotating portion rougher than before.

Next, an embodiment of the second invention will be described with reference to FIGS. 3 and 4. FIG. 3 shows a planetary gear type differential device 35 of the first embodiment of the second invention, and FIG. 4 shows a planetary gear type differential device 37 of the second embodiment thereof. Each device 3 in FIGS. 3 and 4
The friction clutch parts of 5 and 37 are different from each other,
Since the planetary gear sets are common, the same members are designated by the same reference numerals. The left and right directions are the left and right directions in FIGS. 3 and 4, and members and the like without reference numerals are not shown.

A ring gear (driven gear) is fixed to the differential case 39. The ring gear meshes with the drive pinion gear on the propeller shaft side, and the differential case 39 is rotationally driven by the driving force of the engine via the transmission and the propeller shaft.

As shown in FIG. 3 and FIG. 4, left and right hubs 41 and 43 are arranged inside the differential case 39, and the left hub 41 is spline-connected to the drive axle on the left wheel side, and the right hub 41 is right. The hub 43 is spline-connected to the drive axle on the right wheel side. A planetary gear set is arranged inside the differential case 39. The internal gear 45 is a differential case 3
9, the sun gear 47 is formed on the left hub 41, and the first planetary gear 49 and the second planetary gear that are meshed with each other are arranged between them. The first planetary gear 49 meshes with the internal gear 45, and the second planetary gear meshes with the sun gear 47.

The first planetary gear 49 is rotatably supported on the outer pin 51, and the second planetary gear 49 is rotatably supported on the inner pin. Both ends of these pins are supported by left and right carriers 53 and 55. Further, the carriers 53 and 55 are integrated by welding, and the right carrier 55 is integrally formed with the right hub 43.

In these embodiments, the internal gear 45
And a first planetary gear 49, that is, a backlash between the first planetary gear 49 and the second planetary gear, and a backlash between the second planetary gear and the sun gear 47. The quantities are set to extremely small values.

In some cases, at least one of the meshing back clearances may be set to an extremely small value.

As described above, by setting at least one meshing back clearance among the meshing of each gear to an extremely small value, the internal gear 45, the first planetary gear 49 and the second planetary gear constituting the planetary gear set. The relative rotation between the planetary gears and the sun gear 47 can be braked, and thus the differential rotation between the sun gear 47 and the carrier 55 can be limited. This differential limiting force is due to the friction of the meshing portions of the gears. Therefore, the greater the transmission torque and the rotational speed, the greater the differential limiting force.

Further, in the example of FIG. 3, a cone clutch 57 (friction clutch) is formed between the differential case 39 and the left carrier 53, and the differential case 39 and the carrier 53.
A disc spring 59 (preloading spring) is arranged between and to constantly press the cone clutch 57 to give an appropriate initial torque.

Further, in the example of FIG. 4, the cone clutch 57
In addition to this, another cone clutch 61 (friction clutch) is arranged. This cone clutch 61 is the sun gear 47
Clutch member 63 and carrier 53 movably engaged with each other
It is formed between and. These cone clutches 5
7 and 61 are constantly pressed by a disc spring 65 arranged between the differential case 39 and the clutch member 63, and are given an appropriate initial torque.

With such an initial torque, an appropriate differential limiting force can always be obtained in each of the planetary gear type differential devices 35 and 37 regardless of the transmission torque or the rotational speed. In addition,
Needless to say, if the initial torques are the same, the load on the cone clutches 57 and 61 is lighter in the example of FIG.

Next, an embodiment of the third invention will be described with reference to FIGS. FIG. 5 shows a planetary gear type differential device 67 of the first embodiment of the third invention, and FIG. 6 shows a planetary gear type differential device 69 of the second embodiment thereof. The planetary gear sets of FIGS. 5 and 6 are common, and members having the same function are designated by the same reference numerals. The left and right directions are the left and right directions in FIGS. 5 and 6, and members and the like without reference numerals are not shown.

A ring gear (driven gear) is fixed to the differential case 71. This ring gear meshes with the drive pinion gear on the propeller shaft side, and the differential case 71 is rotationally driven by the driving force of the engine via the transmission and the propeller shaft.

As shown in FIG. 5 and FIG. 6, left and right hubs 73 and 75 are arranged inside the differential case 71, and the left hub 73 is spline-connected to the drive axle on the left wheel side and the right hub 73. The hub 75 is spline-connected to the drive axle on the right wheel side. A planetary gear set is arranged inside the differential case 71. The internal gear 77 is a differential case 7
1, the sun gear 79 is formed on the left hub 73, and the first planetary gear 81 and the second planetary gear 83 (FIGS. 7 and 8) meshing with each other are arranged between them. Has been done. The first planetary gear 81 meshes with the internal gear 77, and the second planetary gear 83 meshes with the sun gear 79.

The first planetary gear 81 is rotatably supported on the outer pin 85, and the second planetary gear 83 is rotatably supported on the inner pin 87 (FIGS. 7 and 8). These pins 85, 87 have left and right carriers 89, 9 on both ends.
Supported by 1. Further, the carriers 89 and 91 are integrated by welding, and the carrier 91 on the right is the hub 75 on the right.
It is formed integrally with.

FIG. 7 shows the meshing state of each gear at the time of forward drive when the internal gear 77 is rotated in the direction of arrow P,
FIG. 8 shows the meshing state of the gears when the internal gear 77 is rotated in the direction of the arrow Q during the backward drive or during coasting.

In both figures, R ₁ is the mesh pitch radius of the internal gear 77, R ₂ is the mesh pitch radius of the sun gear 79, and γ ₁ is the pitch radius of the first and second planetary gears 81 and 83. , Α indicates the meshing pressure angle.

According to the first aspect of the present invention, a differential limiting force due to a frictional force is generated in the rotating portions of the planetary gears 81 and 83 with respect to the pins 85 and 87.

As shown in FIGS. 7 and 8, the second planetary gear 83 is the first planetary gear 83 with respect to the forward drive rotation direction of the internal gear 77, that is, the direction of arrow P in FIG. 7 (forward). Gear 8
It is arranged behind 1.

In FIG. 7, during forward drive on a good road surface, the internal gear 77 is driven and rotated in the direction of arrow P, and at that time the planetary gears 81 and 83 and the pins 85 and 87 that pivotally support them. , The sun gear 79 rotates almost as a unit without rotating relatively, and is connected to the right axle 75 and the left hub 73 (sun gear 79) connected to the right hub 75 (carrier 91). The rotation speed and drive torque of the left axle are almost the same.

At that time, the meshing pitch points P ₁ , P ₂ , P ₃
In the direction of each line of action passing through, force F ₁ and its reaction force F _1R , which are component components of the force in the direction of arrow P, force F ₂ and its reaction force F _2R
And a force F ₃ and its reaction force F _3R are generated. Since the force F ₁ and the reaction force F _2R act on the first planetary gear 81, the resultant force M presses the planetary gear 81 against the pin 85 that fixes the carrier 89, 91 in the direction of arrow M. Therefore, a large frictional force is generated between the pin 85 and the planetary gear 81, so that the rotation of the planetary gear 81 is appropriately limited.

Since the force F ₂ and the reaction force F _3R act on the second planetary gear 83, the resultant force N of the second planetary gear 83 against the pin 87 that fixes the planetary gear 83 to the carriers 89 and 91. It presses in the direction of arrow N, and as a result, a large frictional force is generated between the pin 87 and the planet gear 83, whereby the rotation of the planet gear 83 is appropriately limited.

Thus, the first and second planetary gears 81,
The rotation of 83 is moderately restricted, so that the left hub 7
The differential rotation between 3 (sun gear 79) and the right hub 75 (carrier 91) is appropriately limited.

Next, in FIG. 8, the internal gear 77 is driven and rotated in the direction of the arrow Q at the time of reverse drive or coasting on a good road surface, and at that time, the planetary gears 81 and 83 are respectively rotated.
The pins 85 and 87 pivotally supporting the sun gear 79 and the sun gear 79 rotate almost integrally without rotating relatively to each other, and the right axle on the carrier 91 side and the sun gear 79.
The rotation speed and drive torque of the left side axle are substantially the same.

At that time, the meshing pitch points P ₁ , P ₂ , P ₃
In the direction of each line of action passing through, force F ₁ and its reaction force F _1R , which are component components of the force in the direction of arrow Q, force F ₂ and its reaction force F _2R
And a force F ₃ and its reaction force F _3R are generated. Since the force F ₁ and the reaction force F _2R act on the first planetary gear 81, the resultant force M is in the direction of arrow M with respect to the pin 85 fixed to the carriers 89 and 91. This causes a smaller frictional force between the pin 85 and the planetary gear 81 than in the case of FIG. 7, which limits the rotation of the planetary gear 81 to an appropriate degree.

Since the force F ₂ and the reaction force F _3R act on the second planetary gear 83, the resultant force N thereof is the pin 87 which fixes the planetary gear 83 to the carriers 89 and 91.
On the other hand, it is pressed in the direction of the arrow N, so that a smaller frictional force is generated between the pin 87 and the planetary gear 83 than in the case of FIG. 7, whereby the rotation of the planetary gear 83 is appropriately limited. ..

Thus, the first and second planetary gears 8 are
1, 83 is appropriately restricted in rotation, so that the left hub 73 (sun gear 79) and the right hub 75 (carrier 9
The differential rotation with respect to 1), in other words, the differential rotation between the left axle and the right axle is limited to a degree suitable for reverse drive or coasting.

Incidentally, the resultant forces M and N in FIG. 7 and FIG.
In order to increase the value of, the value of the meshing pressure angle α should be increased.

Further, in the example of FIG. 5, a multi-plate clutch 93 (friction clutch) is provided between the left carrier 89 and the sun gear 79.
Are arranged, and in the example of FIG. 6, the internal gear 77 and the sun gear 79 are arranged.
A multi-plate clutch 95 (friction clutch) is arranged between the and. These clutches 93, 95 are on the right carrier 9
1 and the differential case 71 are appropriately pressed by a disc spring 97 (preload spring), and each is given an initial torque.

Next, the operation of each embodiment having the above configuration will be described.

Even if the left wheel slips and the left shaft torque decreases while the vehicle is traveling, for example, due to the condition of the road surface, in the case of the differential device 1 according to claim 1, the first planetary gear 13 and Alternatively, due to the friction torque of the rotating portion between the second planetary gear 15 and the carriers 21, 23, it is possible to prevent the sun gear 11 and the left axle connected to the sun gear 11 from over-rotating and the accompanying reduction in the rotational speed of the right axle. The drive torque of the right axle does not decrease so much,
An appropriate distribution of drive torque can be obtained between the left and right axles.

Further, the differential device 35, 37 according to the second aspect.
In this case, since the amount of meshing back clearance between the gears that make up the planetary gear set is extremely small, braking torque is applied to the relative rotation of each gear, and for example, when the left wheel slips, the drive torque of the right axle decreases so much. Instead, an appropriate distribution of drive torque can be obtained between the left and right axles.

Further, a differential device 67, 69 according to claim 3
In this case, since the second planetary gear 83 is arranged rearward of the first planetary gear 81, a relatively large braking torque is applied during forward drive, and a relatively small braking torque is applied during reverse drive or coasting. 83, which provides an appropriate distribution of drive torque between the left and right axles.

In addition to this, in the differential devices 1, 35, 37, 67, and 69 described in each claim, as described in each embodiment, the initial torque of the friction clutch has no relation to the transmission torque or the rotational speed. Therefore, a proper differential limiting force can always be obtained.

FIG. 9 is a torque distribution characteristic diagram according to the present invention obtained by an experiment, in which the right axle torque T _R is plotted on the horizontal axis.
The vertical axis represents the left axle torque T _L. In the figure, lines a and a'represent the torque distribution limit of the left axle when the torque of the right axle decreases, and lines b and b'represent the torque distribution limit of the right axle when the torque of the left axle decreases. is there. In addition,
Lines a and b are due to the initial torque of the friction clutch.

While the vehicle is traveling, normally, the vehicle is traveling within a range surrounded by the limit lines a and b'and the limit lines b and b ', that is, a hatched range. For example, even when the left wheel slips and the left axle torque T _L decreases to T _{L1 as} shown by the point A, the right axle torque T _R is relatively large and an appropriate drive torque T _R1 is obtained. ..

On the contrary, for example, even when the right wheel slips and the right axle torque T _R decreases, the left axle torque is the same as that described in the lines b and b'due to the limit characteristics shown by the lines a and b '. T _L is relatively large, and an appropriate driving torque can be obtained.

Lines C and C'and D and D'in the characteristic diagram shown in the third quadrant of the figure are experimentally obtained limit characteristics according to the present invention at the time of vehicle reverse travel or coasting. Which is slightly weaker than the characteristic during forward drive shown in the first quadrant. Line C'and line D'are due to the initial torque of the friction clutch. Due to this characteristic, it is possible to prevent the understeer from becoming strong when the vehicle enters a corner, and there is an effect that it does not cause interference with the ABS (anti-skid brake system).

Even if the axial torque on the slip side is small, such as during low-speed traveling, due to the differential limiting force due to the initial torque indicated by the lines a ', b', d'and c ', on the anti-slip side, for example, Axial torque sufficient to escape from a rough road is obtained, and the running performance of the vehicle is kept high.

FIG. 10 is a torque distribution characteristic diagram obtained as a result of an experiment, which is conventionally well performed, in which a needle bearing is interposed in the relative rotating portion of the planetary gear and the carrier, and the value of the friction coefficient is reduced. In this case, for example, when the left axle slips and the left axle torque T _L decreases to T _{L2 as} shown by point B on the line, the right axle torque T _R also greatly decreases and TR ₂ I found out that.

Similarly, when the right axle torque slips and the right axle torque T _R decreases, the left axle torque T _L also becomes very small, as can be seen from the line E. Further, unlike the characteristics of FIG. 9, there is no function of compensating the differential limiting force at the time of low shaft torque by the initial torque.

As described above, the torque distribution characteristic according to the present invention is superior to the conventional characteristic.

Further, unlike the conventional example, the differential device of the present invention does not require control because the driving device such as the actuator or the electromagnetic clutch that directly consumes the output of the engine is not used, and the differential device is easy to handle. In addition, it has low engine power loss, improved fuel efficiency, simple structure, and small size and light weight.

[0073]

As described above, according to the invention of claim 1, the differential limiting means is provided in the rotating portion of the first planetary gear and / or the second planetary gear and the carrier. Even if the drive torque of the drive shaft decreases, the drive torque of the other drive shaft does not significantly decrease, and an appropriate distribution of the drive torque can be obtained between the one drive shaft and the other drive shaft. ..

Further, the invention according to claim 2 is the meshing back clearance between the internal gear and the first planetary gear, the meshing back clearance between the first planetary gear and the second planetary gear, and the second planetary gear. At least one of the meshing back gaps between the gears and the sun gear is made extremely small, so that the internal gear, the first planetary gear, the second planetary gear, and the sun gear that form the planetary gear set are extremely small. The relative rotation between the two drive shafts is moderately braked, so that even if the drive torque of one drive shaft decreases, the drive torque of the other drive shaft does not decrease significantly. A proper distribution of the driving torque is obtained between and.

Further, in the invention according to claim 3, since the second planetary gear is arranged rearward of the first planetary gear with respect to the forward drive direction of the internal gear, a relatively large braking torque is applied during forward drive. Can be applied to each gear, and a relatively small braking torque can be applied to each gear during reverse drive or coasting, whereby between one drive shaft and the other drive shaft during forward drive and Appropriate distribution of the drive torque can be obtained depending on the reverse drive or the coasting.

Further, in the inventions of the respective claims, the differential limiting force can be obtained at a low speed and the like by the friction clutch and the preload spring which gives the initial torque to the friction clutch.

As described above, the present invention is easy to handle because it does not use a driving source such as an actuator or an electromagnetic clutch that consumes the output of the engine, and the power loss of the engine is small, the fuel consumption is improved, and the structure is improved. Simple, small and lightweight.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the first invention.

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

FIG. 3 is a sectional view showing a first embodiment of the second invention.

FIG. 4 is a sectional view showing a second embodiment of the second invention.

FIG. 5 is a sectional view showing a first embodiment of the third invention.

FIG. 6 is a sectional view showing a second embodiment of the third invention.

FIG. 7 is an explanatory diagram of each embodiment of the third invention (during forward drive).
Is.

FIG. 8 is an explanatory diagram of each embodiment of the third invention (during reverse drive or during coasting).

FIG. 9 is a torque distribution characteristic diagram of each of the embodiments of the present invention.

FIG. 10 is a torque distribution characteristic diagram of a conventional differential device.

[Explanation of symbols]

 1,35,37,67,69 Planetary gear type differential device 3,39,71 Differential case 9,45,77 Internal gear 11,47,79 Sun gear 13,49,81 First planetary gear 15,83 2 planetary gears 21,23,53,55,89,91 Carrier 31,57,61 Cone clutch (friction clutch) 33,59,65,97 Disc spring (preload spring) 93,95 Multi-plate clutch (friction clutch)

Claims (3)

[Claims] 1. An internal gear fixed to a driven gear and a differential case, a sun gear coaxial with the internal gear and rotatably arranged with respect to the differential case, and meshed with the internal gear. A first planetary gear, a second planetary gear that meshes with the first planetary gear and also meshes with the sun gear, and rotatably pivotally supports the first and second planetary gears, respectively. A planetary gear type differential device comprising a carrier rotatably disposed with respect to the differential case, the sun gear being connected to one drive shaft, and the carrier being connected to the other drive shaft. There is provided a differential limiting means provided at a rotating portion between the carrier and the first planetary gear and / or the second planetary gear, a friction clutch for limiting differential, and an appropriate engaging force to the friction clutch. Characterized by having a preload spring Planetary gear type differential. 2. An internal gear fixed to a driven gear and a differential case, a sun gear coaxial with the internal gear and rotatably arranged with respect to the differential case, and meshed with the internal gear. A first planetary gear, a second planetary gear that meshes with the first planetary gear and also meshes with the sun gear, and rotatably pivotally supports the first and second planetary gears, respectively. A planetary gear type differential device comprising a carrier rotatably disposed with respect to the differential case, the sun gear being connected to one drive shaft, and the carrier being connected to the other drive shaft. And a meshing back gap between the internal gear and the first planetary gear, a meshing back gap between the first planetary gear and the second planetary gear, and the second planetary gear and the sun gear. At least one of the mating back gaps A planetary gear type differential gear having a friction clutch for limiting the differential and a preload spring for giving an appropriate engaging force to the friction clutch, while reducing the amount of 3. An internal gear fixed to a driven gear and a differential case, a sun gear coaxial with the internal gear and rotatably arranged with respect to the differential case, and meshed with the internal gear. A first planetary gear, a second planetary gear that meshes with the first planetary gear and also meshes with the sun gear, and rotatably pivotally supports the first and second planetary gears, respectively. A planetary gear type differential device comprising a carrier rotatably disposed with respect to the differential case, the sun gear being connected to one drive shaft, and the carrier being connected to the other drive shaft. Therefore, the second planetary gear is arranged rearward of the first planetary gear in the forward drive direction of the internal gear, and a friction clutch for limiting the differential and an appropriate engaging force for the friction clutch are provided. Characterized by having a preload spring to give Planetary gear type differential gear.