JPH02261945A - Torque transmitting mechanism for four-wheel drive car - Google Patents

Abstract

PURPOSE:To eliminate braking phenomena, reduce heat emission, and enhance the force transmitting capacity by allowing a casing capable of relative rotation with respect to shaft to hold a bevel gear meshing with another bevel gear at the shaft end, sealing the two gears, fitting the cavity with lubricant, and putting the two gear surface running spaces in communication through a small section path. CONSTITUTION:A casing 8 is arranged with possibility of relative rotation with an input shaft 2, at whose end a bevel gear 6 is fixed, and four bevel gears 10, 12, 14, 16 meshing with the first named 6 are supported at this casing 8 and sealed, and the cavity is filled with lubricant. The spaces 18, 20, 22, 24, 26 accommodating these bevel gears 6, 10, 12, 14, 16 constitute a gear pump, which is put in outlet blocked condition when the difference in the revolving speed the input shaft 2 and the output shaft 4 in direct coupling with casing. This will eliminate braking phenomena and reduce heat emission, and a sufficiently large transmissive force is accomplished even though the revolving speed difference between the input and output shafts 2, 4 is large.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotational force transmission mechanism, and particularly to a rotational force transmission system applied to a driving force transmission system of a four-wheel drive type automobile called a so-called full-time 4WD. Regarding the mechanism.

[Prior art and problems to be solved by the invention] Conventionally,
In a four-wheel drive vehicle, so-called full-time 4WD, the driving torque from the engine is directly connected to one of the front wheels and rear wheels via a clutch and transmission, and fluid is used as a driving force transmission medium for the other. The connection is made through a rotational force transmission mechanism used as a rotary force transmission mechanism. When the wheels on the directly coupled side slip on the road surface for some reason, a difference occurs between the rotational speed of the engine-side rotating shaft and the rotational speed of the wheel-side rotating shaft in the rotational force transmission mechanism. Based on this, driving force is transmitted via fluid so that the rotational speed of the wheel-side rotating shaft matches the rotational speed of the engine-side rotating shaft.

Further, a differential mechanism for distributing the driving force to the left and right wheels is interposed in the driving force transmission path, and this differential mechanism has a rotational force transmission function for the 4WD. has also been proposed.

An example of a rotational force transmission mechanism or a differential m mechanism that uses the fluid as a driving force transmission medium is one using a viscous coupling, which utilizes the shear resistance of the fluid. Therefore, there are the following problems.

(a) The so-called tight corner braking phenomenon occurs, and braking occurs even during normal driving, resulting in considerable energy loss and relatively large heat generation, making it unsuitable for off-road driving, such as on sandy terrain. It is said that

(b) Even if the difference in rotational speed between the input side and the 8-wheel side becomes relatively large, the transmitted force does not become so large.

Therefore, in view of the above-mentioned problems of the prior art, the present invention can be applied to a drive power transmission system that distributes drive force to the front and rear wheels of a full-time 4WD vehicle, and a differential mechanism that distributes drive force to both left and right wheels of a full-time 4WD vehicle. The purpose of the present invention is to provide a novel rotational force transmission mechanism that generates less heat and generates a sufficiently large transmission force even when the difference between the output shaft rotational speed and the input shaft rotational speed is large.

[Means for Solving the Problems] According to the present invention, in order to achieve the above objects, a first bevel gear is attached to the end of the first rotating shaft, and the first rotating shaft A casing is arranged to be relatively rotatable about the rotation center of the shaft, the casing is connected to the second rotation shaft, and the casing has a rotation center of the first rotation shaft. A second bevel gear having a rotation center perpendicular to the direction and meshing with the first bevel gear is rotatably held, and the casing seals at least the gear surface running space of the first and second bevel gears. These gear surface running spaces are filled with hydraulic oil, and the first bevel gear and the second bevel gear are connected to each other.
A rotational force transmission mechanism for a 4WD vehicle, characterized in that gear surface running spaces on both sides of a contact position with a bevel gear communicate with each other through a path with a small cross section, and a first output rotation shaft and a second output. A rotating shaft is disposed coaxially and facing each other, a first bevel gear is attached to an end of the first output rotating shaft, and a second bevel gear is attached to an end of the second output rotating shaft. A casing is arranged so as to be able to rotate relative to the two output rotation shafts around the rotation center, and the casing is connected to the input rotation shaft, and the casing has the above-mentioned second output rotation shaft. a third bevel gear having a rotation center perpendicular to the rotation center of the first output rotation shaft and meshing with the first bevel gear; and a third bevel gear having a rotation center perpendicular to the rotation center of the second output rotation shaft. and a fourth bevel gear that meshes with the second bevel gear is rotatably held, and the casing has at least the first to fourth bevel gears.
The gear surface running spaces of the bevel gears are sealed, and hydraulic oil is filled in these gear surface running spaces.
The gear surface running spaces on both sides of the contact position between the bevel gear and the third bevel gear and the gear surface running spaces on both sides of the contact position between the second bevel gear and the fourth bevel gear are each communicated by a small cross-sectional path. A rotational force transmission mechanism for a 4WD vehicle having a differential lock function,
is provided.

In the present invention, a bypass route can be provided for the communication path with the small cross section.

[Example] Hereinafter, specific examples of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view showing a first embodiment of a rotational force transmission mechanism according to the present invention, and FIG. 2 is a sectional view thereof.

In these figures, 2 is an input rotation axis, and 4 is an output rotation axis. These two shafts are arranged with one end facing each other.

A bevel gear 6 is fixed to the end of the input rotating shaft 2, and a casing 8 is fixed to the end of the output rotating shaft 4. Inside the casing are four bevel gears 10, 12,
14 and 16 are rotatably attached. The rotation centers of these bevel gears are all in a direction perpendicular to the rotation centers of the input rotation shaft 2 and output rotation shaft 4. and,
The rotation centers of bevel gear 10.12 are coaxial, and the rotation centers of bevel gear 14.16 are coaxial.

In FIG. 1, the casing 8 is shown in perspective and the bevel gear 6.10,
Space 18 for rotatably accommodating 12, 14, and 16
, 20, 22, 24.26 are formed. 8a shown in FIG. 2 is a plate attached to the casing 8.

The bevel gear 6 meshes with the bevel gears 10, 12, 14, 16, respectively, and the gear surface of each bevel gear rotates with the tips of its teeth contacting the conical wall surface forming the accommodation space. The bevel gear housing space is filled with hydraulic oil.

FIG. 3 is a schematic diagram for explaining the operation of this embodiment. In this figure, the bevel gears 6 and 1O housed in the space within the casing 8 are shown.

In addition, Fig. 4 shows a 4W engine using the rotational force transmission mechanism of this embodiment.
It is a schematic diagram showing the driving force transmission system of the D car.

The operation of this embodiment will be described below with reference to FIGS. 1 to 4.

Although not shown in Figure 4, the rotational force output from the engine is transmitted to the front differential via the clutch and transmission, and the front differential is directly connected to the front wheels, thereby forming a front wheel drive system. ing. On the other hand, a part of the rotational force transmitted from the engine to the front differential is transmitted to the input rotation shaft 2 of the rotational force transmission mechanism 30 of the first embodiment, and the output rotation shaft 4 of the mechanism is connected to the rear differential 32. It is connected to the rear wheels 34 via, thereby forming a rear wheel drive system.

In this embodiment, when the input rotating shaft 2 rotates according to the driving force from the prime mover, the bevel gear 6 is rotated as shown in FIG.
is rotated in the direction of the arrow, and the bevel gear 10 (same as 12, 14, 16) is rotated accordingly. As a result, in the gear pump composed of the bevel gears 6 and 10 and the casing 8, a pressure difference is generated in the gear surface running space on both sides of the position where both bevel gears mesh.

In FIG. 3, H is the high pressure side and L is the low pressure side.

By the way, in such a gear meshing structure, oil generally leaks to some extent from the high pressure side to the low pressure side, so if the difference in the rotation speed between the input rotating shaft 2 and the output rotating shaft 4 is relatively small, The pressure difference between the high pressure side and the low pressure side is realized slowly, and sufficient leakage occurs during this time. As a result, the rotational force of the bevel gear 6 is transferred to the bevel gears 10 and 1.
2, 14, and 16, and these bevel gears rotate with respect to the casing 8, so that almost no rotational force is transmitted to the casing 8 and the output rotating shaft 4.

On the other hand, if the difference in the rotational speed between the input rotational shaft 2 and the output rotational shaft 4 becomes relatively large (the rotational speed on the input rotational shaft side becomes sufficiently larger than the rotational speed on the output rotational shaft side), the above-mentioned high pressure Since the pressure difference between the high pressure side and the low pressure side increases rapidly, the leakage is not sufficiently performed, and as a result, the gear pump becomes outlet blocked. As a result, the bevel gear 6 and the bevel gears 10.12, 14.16 are fixed to each other, and the rotational force of the input rotating shaft 2 is thus transmitted to the output rotating shaft 4 via the casing 8.

In normal driving conditions of a car, the rotational speed of the front wheel drive system and the rotational speed of the rear wheel drive system are approximately equal, and the rotational force transmission mechanism 30
In this case, the input rotating shaft 2 and the output rotating shaft 4 rotate at almost the same rotation speed, so that the bevel gear 6 and the bevel gears 10, 12,
14. It does not rotate relative to 16, and as a result, the driving force transmission mechanism 30
operates under almost no load conditions.

On the other hand, if the front wheels slip on the road surface for some reason and the rear wheels 34 do not slip on the road surface,
This results in a difference in rotational speed between the front wheels and the rear wheels. In this case, the rotational speed of the input rotational shaft 2 of the rotational force transmission mechanism 30 becomes larger than the rotational speed of the output rotational shaft 4, and the rotational force of the input rotational shaft 2 increases as described above due to the outlet blocking effect of the gear pump. The rotational force is transmitted to the output rotation shaft 4 and transmitted to the rear wheels 34, and this state continues until the rotation speed of the output rotation shaft 4 becomes the same as the rotation speed of the manual rotation shaft 2.

FIG. 5 is an exploded perspective view showing a second embodiment of the rotational force transmission mechanism according to the present invention, and FIG. 6 is a sectional view thereof. This embodiment is an example of application to a rear differential.

In these figures, 52 is an input rotation axis, 54.
55 is the left and right output rotation shafts. These two output rotation shafts are arranged coaxially with one end facing each other,
The input rotating shaft 52 is arranged perpendicularly to these.

A bevel gear 56 is fixed to the end of the input rotating shaft 52, a bevel gear 58 is fixed to the end of the output rotating shaft 54, and a bevel gear 60 is fixed to the end of the output rotating shaft 56.
is fixed. Reference numeral 57 denotes a bevel gear that is rotatably attached to the bevel gear 60 around the rotation center of the output rotation shaft, and this gear meshes with the bevel gear 56. A casing 59 is fixed to the bevel gear 57. Four bevel gears 62, 64, 66, 68 are rotatably mounted within the casing. The rotation centers of these bevel gears are all in a direction perpendicular to the rotation center of the output rotation shaft 54,56. The rotation centers of the bevel gears 62° and 64 are coaxial,
The rotation centers of the bevel gears 66 and 68 are coaxial.

In the fifth section, the casing 8 is shown transparently and in duplicate, and there are spaces for accommodating the bevel gears 58, 60, 62, 64, 66, 68 as shown here. 78.80.82, 84.86.88 are formed.

Bevel gear 58 meshes with bevel gears f32 and f64, respectively, and bevel gear 60 meshes with bevel gear 66.
68, and the gear surfaces of each bevel gear rotate with their tooth tips contacting the conical wall surface forming the accommodation space. The bevel gear housing space is filled with hydraulic oil.

In this embodiment, a gear pump similar to that of the first embodiment is formed including each bevel gear and the casing 59, and has the same function.

Further, FIG. 7 is a schematic diagram showing a driving force transmission system of a 4WD vehicle using the rotational force transmission mechanism of this embodiment as a rear differential.

The operation of this embodiment will be described below with reference to FIGS. 5 to 7.

Although not shown in Fig. 7, the rotational force output from the engine is transmitted to the front differential via the clutch and transmission, and the front differential is directly connected to the front wheels. system is configured. On the other hand, a part of the rotational force transmitted from the engine to the front differential is transmitted to the input rotation shaft 52 of the rotational force transmission mechanism 90 of the second embodiment, and the output rotation shaft 54 of the mechanism.
55 is connected to a rear wheel 92, thereby forming a rear wheel drive system.

In normal driving conditions of the automobile, the rotational speed of the front wheel drive system and the rotational speed of the rear wheel drive system are approximately equal, and the rotational force transmission mechanism 90
is a steady state in which the ratio of the rotation speed of the input rotation shaft 52 to the average rotation speed of the output rotation shaft 54.55 is approximately constant, and therefore the bevel gear 57, the bevel gear 58.60, and the bevel gear 62
, 64, 66, and 68, and as a result, the driving force transmission mechanism 90 operates under almost no load.

On the other hand, if the front wheels slip on the road surface for some reason and the rear wheels 92 do not slip on the road surface,
This results in a difference in rotational speed between the front wheels and the rear wheels. In this case, the input rotation shaft 52 of the rotational force transmission mechanism 90
The ratio of the rotation speed of the output rotating shaft 54.55 to the average rotation speed of the output rotating shaft 54.55 becomes larger than that in the steady state, and due to the outlet blocking effect of the gear pump, the bevel gear 58 and the bevel gear 62
．． 64 are fixed, and furthermore, the bevel gear 60 and the hevel gear 6 are fixed.
6.68 are in a fixed state, and thus the rotational force of the input rotation shaft 52 is transmitted to the output rotation shaft 54.55,
In this state, the input rotating shaft 520 rotation speed and the output rotating shaft 54.
This continues until the ratio with the average rotational speed of 55 becomes the same as the steady state.

Additionally, if there is a difference in the load between the right rear wheel and the left rear wheel, the rotation speed on the low load side will be higher than the rotation speed on the high load side depending on the load, and the differential function will not be activated. Ru. This differential function works well because the above-mentioned gear pump outlet blocking effect hardly occurs when the difference in rotational speed between the left and right wheels is large (such as during normal turning). When the difference in rotational speed is large enough (as when one of the two wheels is idling), the bevel gear engagement on the idling output rotating shaft side is fixed due to the gear pump outlet block effect, and the gear pump on the idling side is On the other hand, rotational force is transmitted and idling is suppressed.

In the above embodiment, the oil leak path is used as the communication path between the high pressure side and the low pressure side of the gear pump, but in the present invention, a dedicated pipe route may be formed as the communication path. Desired operating characteristics can be obtained by adjusting the cross-sectional area of the bypass route.

[Effect of the invention] As explained above, according to the present invention, full-time 4WD
It can be well applied to the drive power transmission system that distributes the drive force to the front and rear wheels of automobiles, and the differential mechanism that distributes the drive force to both the left and right wheels, with less braking phenomenon, less heat generation, and a lower output shaft rotation speed and input shaft rotation speed. A novel rotational force transmission mechanism is provided in which the transmission force is sufficiently large even when the difference in rotational speed is large. Further, in the present invention, since a bevel gear is used to transmit rotational force, space can be used effectively and the entire mechanism can be downsized.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of a rotational force transmission mechanism according to the present invention, and FIG. 2 is a sectional view thereof. FIG. 3 is a schematic diagram for explaining the operation of this embodiment. FIG. 4 is a schematic diagram showing a driving force transmission system of a 4WD vehicle using the rotational force transmission mechanism of this embodiment. FIG. 5 is an exploded perspective view showing a second embodiment of the rotational force transmission mechanism according to the present invention, and FIG. 6 is a sectional view thereof. FIG. 7 is a schematic diagram showing a driving force transmission system of a 4WD vehicle using the rotational force transmission mechanism of this embodiment as a rear differential. 2: Input rotation axis, 4: a rotation axis, 6.10, 12
, 14, 16: bevel gear, 8: casing, 30
: Rotational force transmission mechanism, 32: Rear differential, 52: Input rotating shaft, 54.55: Output rotating shaft, 56.57, 58.60.62, 64.66°68 = Bevel gear, 59: Casing, 90: Rear differential. Arm ○

Claims (4)

[Claims] (1) A first bevel gear is attached to the end of the first rotating shaft, and a casing is arranged to be rotatable relative to the first rotating shaft around its rotation center, and the casing A second bevel gear is connected to the second rotating shaft, and the casing has a rotation center perpendicular to the rotation center of the first rotating shaft, and a second bevel gear that meshes with the first bevel gear is rotatable. The casing seals at least the gear surface running spaces of the first and second bevel gears, and these gear surface running spaces are filled with hydraulic oil. 4W, characterized in that the gear surface running spaces on both sides of the contact position with the second bevel gear communicate with each other through a path with a small cross section.
D Rotational force transmission mechanism for automobiles. (2) The rotational force transmission mechanism for a 4WD vehicle according to claim 1, wherein the small cross-section communication path includes a bypass route. (3) A first output rotation shaft and a second output rotation shaft are disposed coaxially and oppositely, a first bevel gear is attached to an end of the first output rotation shaft, and a first bevel gear is attached to an end of the first output rotation shaft, and A second bevel gear is attached to the end of the output rotation shaft of No. 2, and a casing is arranged so as to be able to rotate relative to the two output rotation shafts around their rotation centers. a third bevel gear connected to the shaft, the casing having a rotation center perpendicular to the rotation center of the first output rotation shaft, and meshing with the first bevel gear; and the second output rotation shaft. having a rotation center in a direction perpendicular to the rotation center of the rotation axis, and the second
A fourth bevel gear that meshes with the bevel gear is rotatably held, and the casing seals at least the gear surface running space of the first to fourth bevel gears,
Hydraulic oil is filled in these gear surface running spaces, and the gear surface running spaces on both sides of the contact position between the first bevel gear and the third bevel gear and the contact between the second bevel gear and the fourth bevel gear. A rotational force transmission mechanism for a 4WD vehicle having a differential lock function, characterized in that the gear surface running spaces on both sides of the position are connected through paths with small cross sections. (4) The rotational force transmission mechanism for a 4WD vehicle according to claim 3, wherein the communication path having a small cross section includes a bypass route.