JPH0481329A - Driving force distributing device - Google Patents

Abstract

PURPOSE:To eliminate the tight corner braking phenomenon at the time of turning traveling by generating a normal directional differential between an outer wheel side output shaft, of which turning locus is large, and a rotary housing and a reverse directional differential between an inner wheel side output shaft, of which turning locus is small, and the rotary housing. CONSTITUTION:A rotary housing 21 of a driving force distributing device 16 is rotated by the torque from an engine through a driving shaft 14, a driving gear 26 and a ring gear 25. At the time of turning traveling, since a difference is generated in the rotating speed of a pair of output shafts 23, 24 with a difference of the turning locus of a right and a left wheels, a differential is generated between the rotary housing 21 and the output shafts 23, 24. Namely, for example, the pressure generated in one space 33 of a left wheel side is lower than the pressure generated in the other space 34 because of forms of each blade 35, 36. The pressure working to a piston 27 is therefore low, and the pushing force never becomes larger than the elastic force of a compression spring 32, and a clutch means 29 is not displaced. As a result, the transfer torque against the differential rotation is reduced to prevent the tight corner braking phenomenon.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a driving force distribution device that distributes torque from an input shaft to two output shafts via a clutch means.

<Prior Art> A differential gear mechanism is generally known as a device that distributes torque from an input shaft to an output shaft (left and right wheels). Furthermore, Japanese Patent Application Laid-Open No. 2-37034, which was previously filed by the present applicant, discloses a system in which the differential gear mechanism is eliminated and the torque from the input shaft is distributed to the left and right wheels via a pair of viscous fluid couplings. There is.

<Problem to be solved by the invention> However, in a four-wheel drive vehicle that transmits torque from the engine to the front and rear wheels, when turning, a rotation difference occurs between the front and rear wheels due to a difference in turning radius, so the torque of the front wheels is transmitted to the rear wheels. transmitted to the ring. At this time, a tight corner braking phenomenon unique to four-wheel drive vehicles occurs, making it difficult to turn smoothly and reducing steering stability.

Means for Solving the Problems> The present invention has been made in view of the above-mentioned conventional problems, and has a structure in which a rotary housing is rotatably supported on a support case, and a ring gear that meshes with a drive gear is attached to the rotary housing. A pair of pistons are slidably fitted on both sides of the rotary housing in the axial direction, and the rotation of the rotary housing is connected to two relatively rotatable output shafts inside each of the pair of pistons. A pair of clutch means for transmitting the transmission is disposed, and a biasing member for absorbing the pressing force acting on the clutch means is interposed between the pair of clutch means, and both sides of the rotating housing and the pair of pistons are disposed. A space part is provided in the rotary housing, and the rotary housing is housed in the space part, engages with the output shaft, and rotates according to the differential rotation speed generated between the rotary housing and the two output shafts, thereby applying pressure to the space part. and a blade that generates different pressures in the space by rotating in forward and reverse directions.

Effect> With the above-described configuration, for example, during turning, a differential movement occurs between the rotating housing and the re-output shaft due to the difference in turning radius. At this time, a positive differential occurs between the output shaft on the outer ring side, which has a large turning radius, and the rotating housing, but on the other hand, a negative differential occurs between the output shaft on the inner ring side, which has a small turning radius, and the rotating housing. occurs. Since the blade rotates in the opposite direction in the space on the inner ring side, the pressure generated in the space on the inner ring side is low, and the pressing force of the piston acting on the clutch means is suppressed, so that there is no displacement of the clutch means. Further, since the pressure generated in the space is smaller than the urging force of the urging member, there is almost no pressing force of the piston acting on the clutch means, and the torque is hardly transmitted to the output shaft on the inner ring side.

On the other hand, in the space on the outer ring side, since the blade rotates in the forward direction, the generated pressure increases, and this pressure presses the piston against the urging force of the urging member. Therefore, the clutch means is displaced and engaged by the pressing force of the piston, so that torque is transmitted to the outer ring.

However, as the piston slides, the axial clearance of the space increases, so the pressure generated in the space does not increase more than necessary, and the torque transmitted to the outer ring is regulated.

Therefore, a tight corner braking phenomenon does not occur during cornering.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 3, lO is an engine, 11 is a transmission, 13 is a front wheel differential, 14 is a drive shaft, 15 is a front wheel, and 16 is a driving force provided in place of the rear wheel differential, which will be described later. Distribution device, 17 indicates the rear wheel. Torque from the engine 10 is transmitted to the front wheel differential device 13 via the transmission 11 to drive the front wheels 15, and is also transmitted to the drive force distribution device 16 via the drive shaft 14 to distribute torque to the rear wheels 17. do.

As shown in FIG. 1, the driving force distribution device 16 includes a rotating housing 21 rotatably supported by a support case 20 attached to a floor panel of an automobile. The rotary housing 21 is composed of a cylindrical housing body 21A and an end cap 21B attached to an opening at one end, and a sealed hollow chamber 22 is formed within the rotary housing 21. A pair of output shafts 23, 24, which are connected to the left and right rear wheels 17, respectively, are rotatably supported on the rotary housing 21 concentrically with the rotation axis of the rotary housing 21, and one end of each of these output shafts 23, 24 is connected to the hollow The room 22 has been invaded. Further, a ring gear 25 is fixed to the rotary housing 21, and this ring gear 25 is meshed with a drive gear 26 attached to one end of the drive shaft 14.

Inside the hollow chamber 22 of the rotary housing 21, a pair of pistons 27.28 are slidably housed on both sides, and a pair of clutch means 29.30 are arranged inside each of these pistons 27.28. There is. A pair of clutch means 29
．． A compression spring (biasing member) 32 is interposed between the clutch members 30 in a resilient state, and the resilient force of the compression spring 32 normally applies pre-torque to the pair of clutch means. Further, a spacer 31 having a width smaller than the interval between the clutch means 29 and 30 is disposed between the clutch means 29 and 30.
．． 30 relative movement amount is limited. Cylindrical spaces 33.34 are formed between one piston 27 and the rotary housing 21 and between the other piston 28 and the end cap 21B, and these spaces 33.34 have axial dimensions. Blades 35 and 36, each having a slightly smaller wall thickness, are housed in a slidable manner. The blades 35, 36 have the same configuration, and their centers are spline-engaged with the outer periphery of the output shaft 23, 24, respectively. As will be described later, each blade 35, 36 generates pressure according to the differential rotation speed between the rotary housing 21 and the output shaft 23 or 24. For example, the fourth
This will be explained based on the diagram.

The blade 36 forcibly moves the high viscosity fluid 41 by rotating relative to the rotating housing 21,
It has a characteristic of generating pressure in the spaces 33, 34 and changing the amount of forced movement of the high viscosity fluid 41 depending on the direction of differential rotation, thereby causing a difference in the pressure generated in the spaces 33, 34. That is, the blades 35, 36 rotate clockwise relative to the rotating housing 21 (reverse differential rotation).
When doing so, it has the function of reducing the pressure generated in the space 33 and the space 34. The detailed operation of the blades 35 and 36 is described in Japanese Unexamined Patent Publication No. 2-21038, so it will be omitted here.

The clutch means 29.30 has a plurality of outer plates and inner plates arranged alternately, the outer plate being spline engaged with the inner periphery of the housing 21, and the inner plate being engaged with the outer periphery of the drive shaft 23.24. Each is splined to an attached clutch hub 55,56.

Next, the operation of the driving force distribution device with the above configuration will be explained.

Due to the torque from the engine 10, the front wheel differential device 13
The front wheels 15 are rotationally driven via the drive shaft 1.
4. The rotating housing 21 is rotated via the drive gear 26 and the ring gear 25.

During normal straight running, the left and right rear wheels 17 rotate at almost the same rotational speed as the front wheels 15, so the rotating housing 2
1 and the two output shafts 23.24, and no pressure is generated in the space 33.34.

However, while traveling straight, for example, when one or both of the front wheels 15 gets stuck in mud or the like and spins idly, the rotary housing 21 and the pair of output shafts 23.2
4, and a pressure corresponding to the differential rotation is generated in the spaces 33 and 34. This pressure presses the pistons 27, 28, and the clutch means 29, 30.
are combined. Therefore, the rotational torque of the rotating housing 21 is distributed to the pair of output shafts 23, 24, and the left and right rear wheels 17
．． 17 to improve escape from mud etc. In this case, the pressure generated in the space 33.34 causes the pair of clutch means 29.30 to compress the compression spring 32 and are respectively displaced, so that both pistons 27.2
8 is suppressed to 1/2 of the total gap amount by the spacer ring 31. Therefore, an increase in the axial clearance in the space portions 33.34 is suppressed, and the space portions 33.34.
34, a high pressure is generated in accordance with the differential rotation.

As a result, the torque transmitted to the differential rotation becomes as shown by the solid line B in FIG. 5, and the ability to escape from the stack is improved.

By the way, during turning, a difference in the rotational speeds of the pair of output shafts 23.24 occurs due to the difference in the turning trajectories of the left and right wheels, so a differential occurs between the rotating housing 21 and the output shafts 23.24. For example, when turning to the left, a positive differential occurs between the right wheel side, which has a large turning trajectory, and the rotating housing 21, whereas a differential movement occurs in the opposite direction, between the left wheel side, which has a small turning trajectory, and the rotating housing 21. Therefore, the blades 35,3
6, the pressure generated in one space 33 on the left wheel side is lower than the pressure generated in the other space 34. As a result, the pressure acting on the piston 27 is low, the pressing force on the clutch means 29 does not become greater than the elastic force of the compression spring 32, and the clutch means 29 is not displaced.

Therefore, when the piston 27 presses the clutch means 29 due to the pressure generated in one of the spaces 33, the clutch means 29
9 becomes able to displace only the entire gap bone of the spacer ring 31 while compressing the compression spring 32, and one space 33
The axial clearance in the space 33 increases, and the space 33
Pressure leaks from the high pressure side to the low pressure side, and the pressure in one space 33 is suppressed. As a result, during cornering, the transmitted torque for differential rotation is reduced as shown by solid line A in FIG. 5, making it possible to prevent tight corner braking.

In addition, in this embodiment, between the clutch means 29 and 30,
A compression spring 32 is interposed in the 2. However, instead of this compression spring 32, a disc spring 50, 51 as shown in FIG. 2 is used.
Even if it is provided between the clutch means 29 and 30, the same effect as the compression spring 32 can be obtained.

<Effects of the Invention> As described above, according to the driving force distribution device of the present invention, during cornering, a positive differential is generated between the output shaft on the outer wheel side, which has a large turning locus, and the rotating housing. A differential in the opposite direction occurs between the output shaft on the inner ring side, which has a smaller turning trajectory, and the rotational bouncing.

At this time, pressure increases in the space on the outer ring side and torque is transmitted to the output shaft on the outer ring side, but the pressure generated in the space on the inner ring side is low; It is smaller than the elastic force of the biasing member, and no torque is transmitted to the output shaft on the inner ring side. Therefore, the torque transmitted to the differential rotation is kept low, and tight corner braking does not occur during cornering, allowing smooth running.

[Brief explanation of the drawing]

The drawings show the present embodiment; FIG. 1 is a diagram showing the driving force distribution device of the present invention, and the second diagram is a diagram showing an application example of FIG. 1.
Figure 3 is an overall configuration diagram of the automobile, and Figure 4 is IV- of Figure 1.
A sectional view of the TV, FIG. 5, is a diagram showing the relationship between transmission torque and differential rotation speed in the present invention. 14... Drive shaft, 16... Driving force distribution device, 20...
...Support case, 23.24...Output shaft, 25...
Drive gear, 26...Ring gear, 27.28...Piston, 29.30...Clutch means, 31...Spacer ring, 32...Biasing member (compression spring)
, 33.34... Space portion, 35.36... Blade, 41... High viscosity fluid, 50.51... Belleville spring.

Claims (1)

[Claims] (1) A rotary housing is rotatably supported on a support case, a ring gear that meshes with a drive gear is provided on the rotary housing, a pair of pistons are slidably fitted on both sides of the rotary housing in the axial direction, and The rotation of the rotary housing is relative to the inside of each of the pistons of the two
A pair of clutch means for transmitting data to each of the two output shafts is disposed, a biasing member for absorbing the pressing force acting on the clutch means is interposed between the pair of clutch means, and the rotating housing and the pair of pistons are connected to each other. A space is provided on both sides,
Generating pressure in the space by being accommodated in the space and engaging with the output shaft and rotating in accordance with the differential rotation speed generated between the rotary housing and the two output shafts;
and a blade that generates different pressures in the space by rotating in forward and reverse directions.