JPS62279138A - Differential gear - Google Patents

Abstract

PURPOSE:To reduce the min. revolution radius and obtain a sufficient drive transmission force by installing the first and second shafts which are engaged through each transmission means of the right and left driving shfts and keeping the revolution speed difference between the both shfts at a prescribed value. CONSTITUTION:The revolution means 64 of the second trailing means 60 which operates independently from the revolution means 56 of the first trailing means 50 is controlled by a controller 70. In other words, when a vehicle turns, the revolution speed difference betweem the right and left front wheels is calculated from the signals supplied from the sensors 72 and 74, and the revolution speed difference between the first and second shafts 30 and 40 is controlled so as to be kept at a prescribed value. Further, a controller 70 judges if a large steering angle is necessary or not, and in case of necessity, the large revolution difference between the right and left front wheels is provided, and the min. turning radius is kept small. Further, when front wheels go over a snow road, the revolution speed corresponding to the car speed is provided, and control is performed so that the revolution speed defference between the both front wheels becomes zero. Therefore, the reduction of the drive transmission force is prevented by suppressing the slip of the front wheels.

Description

3. Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a differential device, and particularly to a differential device suitable as a front differential gear of a front-wheel drive vehicle or a four-wheel drive vehicle.

(Prior Art) A vehicle is typically steered by a steering device by turning the front wheels at a turning angle. In front-wheel drive or four-wheel drive vehicles, the driving wheels and steering wheels are aligned, so a constant velocity joint is built into the left and right drive shafts that extend from the front differential gear to the left and right front wheels, which transmits driving force and adjusts the turning angle. I try to put it on.

(Problem to be Solved by the Invention) Since the joint angle of a constant velocity joint is naturally limited, in front-wheel drive vehicles or four-wheel drive vehicles, as a result of incorporating the constant velocity joint into the drive shaft, the turning angle or steering angle is limited. The angle becomes smaller than in the case of a rear-wheel drive vehicle, and the minimum turning radius becomes larger.

By the way, if one of the plurality of wheels connected to a drive system having a differential device runs onto a road surface with a low coefficient of friction such as snow and spins, due to the inherent characteristics of the differential device,
A phenomenon occurs in which the driving force to other wheels connected to the drive system decreases, or the driving force is not transmitted to the other wheels at all.

The purpose of the present invention is to be able to reduce the minimum turning radius, and to actively suppress when one of the two front wheels attempts to spin, thereby reducing the driving force transmitted to the other front wheel. The object of the present invention is to provide a differential device that can prevent such problems.

(Means for Solving the Problems) The present invention is a differential device that transmits driving force to steerable front wheels via left and right drive shafts, and includes a rotatable case and a a pinion rotatably supported by a pinion shaft; a pair of side gears meshing with the pinion and disposed within the case; and a first shaft rotatably supported about an axis of the case; a first shaft extending from the side gear and engaging one of the left and right drive shafts via a transmission means, and a second shaft rotatably supported about the axis, the other side gear a second shaft extending in a direction opposite to the first shaft and engaging with the other of the left and right drive shafts via a transmission means; and one of the case, the first shaft, and the second shaft. a first driven means built into the first and second driven means;
a second driven means incorporated in one of the case, the first shaft, and the second shaft in which the first driven means is absent; , second means for rotating the second driven means;
a control device to which signals from a steering angle sensor and a vehicle speed sensor are input; the control device controls the rotation speed of the second rotation means to maintain a rotation speed difference between the first and second shafts at a predetermined value; keep.

According to a preferred embodiment of the invention, the second driven means is a worm wheel, and the second rotating means includes a worm.

(Function and Effect) When the vehicle turns, the control device calculates the difference between the rotation speed of the front wheels located on the outside of the turn and the rotation speed of the front wheels located on the inside from the steering angle and vehicle speed, and applies this difference to both front wheels. The second rotating means is controlled so as to provide a rotational speed of .

When the vehicle turns, the control device also determines from the steering angle and vehicle speed whether a large steering angle is necessary for parking, etc. If necessary, it applies a large rotation difference between the left and right front wheels to reduce the minimum turning radius. Keep it small.

When the vehicle is traveling straight, if one of the front wheels runs over snow or the like and the front wheel attempts to rotate at a rotation speed higher than the rotation speed commensurate with the vehicle speed, the control device will adjust the rotation speed of the front wheel to match the vehicle speed. The rotational speed of the second rotating means is controlled so that the rotational speed of the second rotating means is maintained at the same rotational speed and the rotational speed difference between the two front wheels becomes zero.

The differential device is provided with a second driven means and a second rotating means that operate independently of the original driven means and rotating means, and the second rotating means rotates the first and second shafts. Since the rotational speed difference between the two front wheels is maintained at a predetermined level, the minimum turning radius during turning can be reduced, and even if one of the front wheels attempts to spin, power can be reliably transmitted to the other front wheels.

Furthermore, even during normal driving, steering stability can be improved by appropriately adjusting the rotational speed difference between the left and right front wheels.

(Example) As shown in FIGS. 1, 2, and 4, the differential gear lO transmits driving force to the left and right steerable front wheels 12.12 via the left and right drive shafts 14.16. It includes a case 18, a pinion 20 disposed within the case 18, and a side gear 22 disposed within the case.

The case 18 is what is called a differential case, and is disposed within the differential carrier 24 and rotatably supported by a pair of rolling bearings 26 mounted on the differential carrier 24.

A pinion shaft 28 is attached to the case 18.

In the embodiment shown in FIG. 2, a two-wood pinion shaft 28
are arranged perpendicular to each other. These pinion shafts 28 are arranged so that their respective axes are orthogonal to the rotational axis of the case 18. A pair of pinions 20 are mounted on each pinion shaft 28 at intervals in the axial direction, and these pinions 20 are rotatably supported by the pinion shaft 28. When there is one pinion shaft 28, two pinions 20 are rotatably supported by the pinion shaft 28.

Two side gears 22 are arranged within the case 18 at intervals, and each side gear 22 meshes with four pinions 20.

A first shaft 30 is connected to one side gear 22 through serrations, extends in one direction from the case 18, and projects from the differential carrier 24. shaft 3
0 is supported by the shoulder of the case 18 via the post 23 of the side gear 22 and by a pair of rolling bearings 34 via a spur gear 36 of a transmission means 32, which will be described later, and is rotatable about the axis of the case 18.

The transmission means 32 includes a spur gear 36 serrated to the first shaft 30 and a spur gear 38 fixed to the left drive shaft 14 and meshing with the spur gear 36 . The drive shaft 14 is engaged with the drive shaft 14 through the drive shaft 14. The open spur gears 36, 38 have the same number of teeth, so that the rotation of the first shirt 30 is reversed and taken out to the left drive shaft 14.

A second shirt 40 is connected to the other side gear 22 through serrations, extends from the case 18 in a direction opposite to the first shaft 30, and projects from the differential carrier 24. The shaft 40 is supported by the shoulder of the case 18 via the post 23 of the side gear 22 and by a bearing (not shown).

It is rotatable around the axis of the case 18.

The transmission means 42 is the second shaft 40 and the right driver.

It is provided between the shaft 16 and the shaft 16. The transmission means 42 consists of a sprocket or pulley 44 fixed to the second shirt 40, a sprocket or pulley 46 fixed to the drive shaft 16, and a chain or belt 48 stretched between these. shaft 40
is engaged with the drive shaft 16 via a transmission means 42. When the transmission means consists of a sprocket and a chain, the two sprockets have the same number of teeth.

Also, when the transmission means consists of a pulley and a belt, the diameters of the two bobbins are equal, so that the second shaft 40
Rotation in the same direction is taken out to the drive shaft 16.

The first driven means 50 is the case 18 and the first shaft 30
and one of the second shafts 40. Fourth
In the embodiment shown, the driven means 50 is a spur gear and is coupled to the first shaft 30 to the left of the spur gear 36 of the transmission means 32 .

A first rotating means 52 is engaged with the first driven means 50, and together they provide a driving force to the first shaft 30 and the second shaft 40. The first rotation means 52 includes a transmission 54 and a spur gear 5 fixed to the output shaft.
6, and the spur gear 56 meshes with the spur gear 50.

The second driven means 60 is the case 18 and the first shaft 30
and one of the second shafts 40 without the first follower means 50. In the embodiment shown,
The second driven means 60 is a worm wheel and is attached to the case 18.

The second means 62 for rotating the second driven means 60 includes a worm 64, which is rotatably supported on the differential carrier 24, while the worm 64 is rotatably supported on the differential carrier 24;
is attached to the differential carrier 24, and the shaft of the worm 64 is connected to the output shaft 68 of the electric J1166 through serrations.

A control device 70 is connected to an electric motor 66 included in the second rotation means 62 . Signals from the steering angle sensor 72 and vehicle speed sensor 74 are input to the control device 7o.
controls the rotation speed of the electric motor 66.

Since the differential device 80 shown in FIG. 3 is equipped with its own reversing mechanism, the transmission means is simplified. The structure of the main parts of the differential device 80 is the same as that of the differential device 1o. That is,
The differential device 80 includes a rotatable case 18, a pinion 20 rotatably supported by a pinion shaft 28 disposed within the case 18, and a pair of side gears 22 meshed with the pinion 20 and disposed within the case 18. , case 1
A first shaft 30 extends from one side gear 22, which is rotatably supported around the axis of the case 18, and a second shaft 30 extends from the other side gear 22, which is rotatably supported around the axis of the case 18. shaft 40
including.

In the differential device 80, a post 82 is provided on the first shaft 3o, and a bevel gear 84, which is a first driven means, is provided on the post 82.
is attached by Porto 86. bevel gear 8
4 meshes with a small bevel gear 88 included in the first rotating means, and the small bevel gear 88 is connected to the transmission.

The first shaft 30 engages with the left drive shaft via a transmission means such as a constant velocity joint.

The worm wheel 60, which is the second driven means, is in the case 1.
8 , while a worm 64 is rotatably supported by the differential carrier 24 and meshes with the worm wheel 60 . The worm 64 is rotated by an electric motor.

The auxiliary differential 90 is the second shirt of the differential 80) 4
Incorporated into 0. In the differential device 80, the driving force is transmitted to the bevel gear 88 and the bevel gear 8 meshing with the bevel gear 88.
4 to the first shaft 30 and then to the first shaft 3
0 to the second shaft 40 via the pinion 20, side gear 22, etc., the second shaft 40 rotates in the opposite direction to the first shaft 30 (the direction of rotation is determined by the differential bag). The same is true for mto.), and the auxiliary differential device 90 functions to make the rotational direction of the output portion of the second shaft 40 the same as the rotational direction of the first shaft 30.

In the second differential 90, there is no rotatable case and the pinion shaft 92 is connected to the differential carrier 24.
Fixed. Two pinions 94 are disposed within differential carrier 24 and rotatably supported by pinion shaft 92. A pair of side gears 96.
The first portion 41a of the second shaft 40 is integrally projected from one side gear 96, which is disposed within the differential carrier 24 and meshes with the pinion 94.
This first portion 41a is the side gear 22 of the differential bag 2180.
The serrations are joined to the serrations. The second of the second shaft 40
The portion 41b is connected to the other side gear 98 through serrations and protrudes from the differential carrier 24.

The second portion 41b engages with the right drive shaft via a transmission means such as a pole joint.

(Operation of the Embodiment) When the vehicle is running, the driving force transmitted from the transmission gear 54 is transmitted to the left drive shaft 14 on the one hand and to the right drive shaft 16 on the other hand through the differential device 10. Rotate the front wheel 12.

When driving, when the steering wheel 100 turns the front wheels 12, the control device 70 uses the difference between the rotation speed of the front wheels 12 located on the outside of the turn and the rotation speed of the front wheels 12 located on the inside to steer the turn. It is calculated based on the signals from the angle sensor 72 and the vehicle speed sensor 74, and the rotation speed of the electric motor 66 is normally controlled so as to give the rotation speed of this difference to both front widths 12.

However, when a large steering angle is required, such as when parking, etc.
The control device 70 performs the control shown in FIG. 5 to cope with this. The vehicle speed V obtained by the vehicle speed sensor 74 is compared with the set value v0 (102), and if the vehicle speed V is less than or equal to the set value vo, normal control is performed. When the vehicle speed ■ is smaller than the set value vo, the steering angle θ obtained by the steering angle sensor is compared with the set value θ0 (104
), the steering angle θ is the set value θ. If it is below, normal control is performed. However, when the steering angle θ is larger than the set value θ0, a rotation speed difference larger than the calculated value is given to the front width 12.
The rotation speed difference in this case is controlled (106) so that it increases in proportion to the magnitude of the steering angle.

Since the second driven means is a worm wheel 60 and the second rotating means includes a worm 64.

Although the worm 64 allows rotation of the worm wheel 60, the reverse operation, i.e., the rotation of the worm wheel 60 is possible.
Rotating the worm 64 by
Therefore, the differential device is reliably controlled by the rotational speed of the electric motor 66.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the differential gear taken along the axis of rotation of the case, Figure 2 is a cross-sectional view taken along line 2-2 in Figure 1, and Figure 3 is a cross-sectional view of the differential gear. FIG. 4 is a cross-sectional view of the embodiment taken along the rotational axis of the case, FIG. 4 is a diagram schematically showing a state in which the differential gear is installed in a vehicle, and FIG. 5 is a control flowchart. 10.80: Differential gear, 12: Front wheel, 14.16: Drive shaft, 18: Case, 20:
pinion, 22: side gear, 24: differential carrier, 30: first shaft, 32.
42: transmission means, 40: second shaft, 50.82: first driven means, 60: worm wheel, 56.88: first rotation means, 64: worm, 66: electric VJ machine. Agent Patent Attorney Nobuyuki Matsunaga 2 Figure 4 Figure 5 Normal Control Normal Control

Claims (2)

[Claims] (1) A differential device that transmits driving force to steerable front wheels via left and right drive shafts, which includes a rotatable case and a pinion rotatably supported by a pinion shaft disposed within the case. , a pair of side gears disposed in the case and meshing with the pinion, and a first shaft rotatably supported about the axis of the case, the first shaft extending from one of the side gears and the left and right drive shafts. a first shaft that engages with one of the side gears via a transmission means, and a second shaft that is rotatably supported about the axis, the second shaft being rotatably supported from the other side gear in a direction opposite to the first shaft. a second shaft extending to the left and right drive shafts and engaging the other of the left and right drive shafts via a transmission means; a first driven means incorporated in one of the case, the first shaft, and the second shaft; , a first means for rotating the driven means to apply a driving force to the first and second shafts, and one of the case, the first shaft and the second shaft and the first driven member The control device includes a second driven means incorporated in a device without means, a second means for rotating the second driven means, and a control device into which signals from a steering angle sensor and a vehicle speed sensor are input. A differential device, wherein the device controls the rotation speed of the second rotation means to maintain a predetermined rotation speed difference between the first and second shafts. (2) the second driven means is a worm wheel;
The differential device according to claim 1, wherein the second rotation means includes a worm.