JPH02300553A - Torque transmitting mechanism for four-wheel drive vehicle - Google Patents

Abstract

PURPOSE:To enlarge transmission power by fitting an inner casing at the end part of a first shaft, supporting pump gears at the internal casing, fitting an outer casing at the end part of a second shaft, and forming a ring to be engaged with the pump gears at the inner surface of the outer casing. CONSTITUTION:When an input shaft 2 is rotated, pump gear shafts 6a-6c are rotated around the rotational center 2' of the input shaft. In case the rotating speed of an output shaft 4 is different from that of the shaft 2, pump gears 8a-8c interlocked with a ring gear 18 are rotated around the shafts 6a-6c, so that pressure difference is generated in a gear face running space inside the position where each pump gear and the ring gear 18 are interlocked, and oil leaks to a certain extent from the high pressure side to the low pressure side. When the rotating speed of the shaft 2 is relatively large, the above-mentioned leak is not sufficiently performed, which will place the pump gears, the ring gear and casings 10, 16 in the rigidly secured state, and the torque of the shaft 2 is thus transmitted to the casing 16.

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.

An example of a rotational force transmission mechanism that uses the above-mentioned fluid as a driving force transmission medium is what is called a viscous coupling, but since this utilizes the shear resistance of the fluid, it has the following problems. .

(a) A so-called tight corner braking phenomenon occurs, considerable energy loss occurs, and the amount of heat generated is relatively large, so it is said to be unsuitable for off-road driving, such as on sandy terrain.

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

Therefore, in view of the problems of the prior art described above, the present invention can be applied to a drive power transmission system that distributes drive power to the front and rear wheels of a full-time 4WD vehicle, and reduces the occurrence of braking phenomena.
It is an object of the present invention to provide a novel rotational force transmission mechanism that generates little heat (and has 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 rotation shaft and a second rotation shaft are disposed coaxially and facing each other, and An internal casing is attached to the end of the first rotating shaft, and a pump gear is attached to the internal casing so as to be rotatable around an axis eccentric from and parallel to the rotational center of the first rotating shaft. An outer casing is attached to the end of the second rotating shaft, and a ring gear that meshes with the pump gear is formed on the inner surface of the outer casing. The gear surface running spaces of the pump gear and ring gear are sealed, and hydraulic oil is filled in these gear surface running spaces, and the gear surfaces on both sides of the contact position of the pump gear and ring gear are sealed. The running space communicates through a path with a small cross section, and the inner casing is provided with a hydraulic oil reservoir that communicates with the gear surface running space, and the hydraulic oil in the hydraulic oil reservoir is transferred into the gear face running space. A rotational force transmission mechanism for a 4WD vehicle is provided, characterized in that a mechanism is provided for supplying power to the non-high pressure side of the 4WD vehicle.

In the present invention, a hydraulic oil pressurizing means using a spring can be provided in the hydraulic oil reservoir as a mechanism for supplying the hydraulic oil to the non-high pressure side in the gear surface running space, and
As the mechanism, communication passages are provided between the hydraulic oil reservoir and the non-high pressure side and the high pressure side in the gear surface running space, and a check valve is provided in the communication passage to allow flow only to the non-high pressure side. It is possible to intervene.

Further, in the present invention, a plurality of the pump gears are provided,
These can be arranged at rotationally symmetrical positions with respect to the rotation center of the first rotation axis.

[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 the rotational force transmission mechanism according to the present invention, FIG. 2 is a perspective view showing its assembled state, and FIGS. 3 and 4 are sectional views thereof. It is.

In these figures, 2 is an input rotation axis, and 4 is an output rotation axis. These two rotating shafts are arranged with one end facing each other. Note that 2' and 4' are the rotation center of the input rotation shaft and the rotation center of the output rotation shaft, respectively, and these coincide.

A plate-shaped pump gear support member 5 is fixed to the end of the input rotation shaft 2, which is perpendicular to the input rotation shaft rotation center 2'.

One ends of pump gear rotation shafts 6a, 6b, and 6c, which are parallel to the input rotation shaft rotation center 2', are attached to the support member. These rotating shafts are arranged rotationally symmetrically about the input rotating shaft rotation center 2' at angular intervals of 120 degrees. Equivalent pump gears 8a, 8b, 8c are rotatably attached to the rotating shafts 6a, 6b, 6c, respectively. The support member 5 also includes an internal casing l.
O is fixed. The inner casing has cylindrical inner wall surfaces 12a, 12b in which the tips of the teeth of the pump gears 8a, 8b, 8c are very close to each other.

12c is formed.

On the other hand, an external casing 16 is fixed to the end of the output rotating shaft 4. The outer casing includes the pump gear support member 5, the rotating shafts 6a, 6b, 6C, and the pump gears 8a, 8.
It has a cylindrical shape that covers the parts b, 8c, and the inner casing 10, and an internal ring gear 18 is formed on the inner surface. The ring gear is arranged coaxially with respect to the rotation center 4' of the output rotation shaft, and meshes with the pump gears 8a, 8b, and 8c, respectively. 20 is a plate attached to the external casing 16 from the outside of the pump gear support member 5, and thereby the pump gear support member 5, the rotating shafts 6a, 6b, 6C, the pump gears 8a, 8b,
8c, and the inner casing 10 are sealed. The outer peripheral surface of the inner casing 10 is connected to the ring gear 18.
It is a cylindrical surface with the tips of the teeth very close together.

With the above configuration, the pump gears 8 a , 8
b + 8 c can rotate relative to each other while being engaged with the ring gear 18, and thus the pump gear support member 5, the rotating shafts 6a, 6b, 6c, the pump gears 8a, 8b,
8c, the inner casing 10, the outer casing 16, and the plate 20 can rotate relative to each other around the input rotating shaft rotation center 2' and the output rotating shaft rotation center 4'. The space between the inner casing lO and the outer casing 16 is filled with hydraulic oil.

Note that the internal casing lO has hydraulic oil reservoirs 14a, 1.
4b, 14c, and 14d are provided. These hydraulic oil reservoirs have a cylindrical shape parallel to the rotation center 2' of the input rotating shaft, and cylindrical pieces 15a and 15b that are movable in the axial direction are provided inside them.

15c and 15d are respectively biased toward the output rotation shaft by coil springs. The piece divides each hydraulic oil reservoir into two parts in an air-liquid tight manner, with the part on the coil spring side containing gas and the part on the opposite side containing hydraulic oil.

Furthermore, as shown in FIG. 1, grooves are formed on the end face of the internal casing 1O on the output rotating shaft side to communicate the space between the internal casing 10 and the external casing 16 with each hydraulic oil reservoir. There is. That is, as illustrated in FIG. 3, grooves 11 are formed between the hydraulic oil reservoirs 14a, 14b, and 14c and the cylindrical outer circumferential surface of the inner casing lO, and the grooves 11 are formed between the hydraulic oil reservoirs 14d and the cylindrical outer peripheral surface of the inner casing lO. Inner wall surface 12a.

A groove 13 is formed between each of the grooves 12b and 12c.

FIG. 5 is a schematic diagram showing a driving force transmission system of a 4WD vehicle using the rotational force transmission mechanism of this embodiment.

The operation of this embodiment will be described below with reference to FIGS. 1 to 5.

In FIG. 5, the rotational force output from the engine 42 is transmitted to a front differential 48 via a clutch 44 and a transmission 46, and the front differential is directly connected to front wheels 52 via a universal joint 50. The front wheel drive system is comprised of these. On the other hand, a part of the rotational force transmitted from the engine 42 to the front differential 48 is transmitted to the input rotating shaft 2 of the rotational force transmission mechanism 56 of the above embodiment via the propeller shaft 54 and the universal joint 50. The output rotating shaft 4 of the mechanism is connected to the rear wheels 60 via a rear differential 58 and a universal joint 50, thereby forming a rear wheel drive system.

In this embodiment, when the manual rotation shaft 2 rotates according to the driving force from the engine, the pump gear rotation shafts 6a, 6b, 6
c is rotated around the input rotation shaft rotation center 2', and when the rotation speed of the output rotation shaft 4 is different from the rotation speed of the input rotation shaft 2, the pump gears 8a, 8b, which are meshed with the ring gear 18, 8c is rotated in the direction of the arrow around the rotating shafts 6a, 6b, and 6c as shown in FIG.
It will be done. As a result, each pump gear 8a, 8b.

In each gear pump composed of the ring gear 8c and the ring gear 18, the support member 5, the inner casing lO1, the outer casing 16, and the plate 20, a pressure difference occurs in the gear surface running space on both sides of the position where each pump gear and the ring gear mesh. In FIG. 4, H is the high pressure side and L is the low pressure side.

By the way, in such a structure, oil generally leaks to some extent from the high pressure side to the low pressure side through the gap between the gear and the casing. Therefore, when the input rotation shaft 2 starts rotating from a state where both the input rotation shaft 2 and the output rotation shaft 4 are stopped, if the rotation speed of the manual rotation shaft is relatively small,
The pressure difference between the high pressure side and the low pressure side is realized slowly,
During this time, sufficient leakage occurs. Thereby, the pump gears 8a, 9b, 8c are connected to the rotating shafts 6a, 6b, 6, respectively.
an outer casing 16 which rotates around c and is formed with a ring gear 18 meshing with the pump gear;
And the output rotating shaft 4 hardly rotates.

On the other hand, when the rotational speed of the input rotating shaft 2 is relatively high, the pressure difference between the high pressure side and the low pressure side increases rapidly, so the leakage does not occur sufficiently, and as a result, the gear pump blocks the outlet. , and a large pressure difference continues. As a result, pump gears 8a, 8b, 8c
The ring gear 18, the inner casing 10, and the outer casing 16 are in a fixed state, and thus the rotational force of the input rotating shaft 2 is transmitted to the outer casing 16, and the casing and the output rotating shaft 4 are connected to the input rotating shaft rotation center 2. ' and rotates around the output rotation axis rotation center 4'.

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 to one rotational force transmission mechanism 56.
In this case, the input rotating shaft 2 and the output rotating shaft 4 rotate at almost the same rotation speed, so the pump gear rotating shafts 6a, 6b, 6c and the external casing 16 do not rotate relative to each other, and as a result, the driving force transmission mechanism 56 is almost unloaded. operate in the state.

On the other hand, if the front wheels 52 slip on the road surface for some reason and the rear wheels 60 do not slip on the road surface, a difference in rotational speed will occur between the front wheels and the rear wheels. . In this case, the rotation speed of the input rotation shaft 2 of the rotational force transmission mechanism 56 becomes higher than the rotation speed of the output rotation shaft 4,
Due to the outlet block effect of the gear pump, the rotational force of the input rotating shaft 2 is transmitted to the output rotating shaft 4 as described above, and the rear wheel 6
0, and the rotational speed of the output rotational shaft 4 is thus controlled so as to approach the rotational speed of the input rotational shaft 2.

In this embodiment, since the hydraulic oil in the hydraulic oil reservoir is pressurized by the pressing force of the coil spring, the hydraulic oil can be supplied to the non-high pressure side of the gear surface running space based on this. This increases the overall pressure while maintaining the pressure difference in the gear surface running space, causing vapor lock on the low pressure side even if the leakage of hydraulic oil from the high pressure side to the low pressure side is insufficient. Stable operation is possible without any problems.

Further, since the hydraulic oil reservoir is provided, the amount of hydraulic oil in the casing can be increased, which is advantageous for actively cooling the hydraulic oil if desired.

Furthermore, since an air chamber with variable volume is provided in the hydraulic oil reservoir, when the oil expands as the temperature rises, the volume of the air chamber changes, preventing abnormal pressure rises. damage can be prevented.

FIG. 6 is an exploded perspective view showing a second embodiment of the rotational force transmission mechanism according to the present invention, FIG. 7 is a perspective view showing its assembled state, and FIGS. 8 and 9 are sectional views thereof. and
FIG. 10 is a partial sectional view thereof.

In these figures, the same members as in FIGS. 1 to 4 are given the same reference numerals.

In this embodiment, one hydraulic oil reservoir 14 is formed in the internal casing 10, and the piece 1 is provided in the hydraulic oil reservoir.
5 is biased toward the output rotation shaft by a coil spring. This is the hydraulic oil reservoir 14d of the first embodiment.
The structure is similar to that of However, in this embodiment, the hydraulic oil reservoir 1
The air containing portion 4 communicates with the outside.

Further, in this embodiment, a hydraulic oil distributor is attached to the end surface of the internal casing 10 on the output rotating shaft side. The distributor has plates 24 and 26 attached to both sides of a disc-shaped main body 22 that is perpendicular to the rotation center 2' of the input rotation shaft. FIG. 10 shows a cross-sectional view of the distributor. A passage 27 communicating with the hydraulic oil reservoir 14 is formed in the center of the main body 22 and plate 24 of the distributor.

The main body has six grooves 28a and 28b extending radially from the passage 27 on the end surface on the plate 26 side.

28c, 28d, 28e, and 28f are formed, and passages extending in the axial direction are formed at the tip positions of these grooves, and each passage is provided with a check valve 29 using a coil spring. The valve prevents the hydraulic oil from flowing toward the plate 26 and allows the hydraulic oil to flow in the opposite direction.

A through hole 30 is formed in the plate 24 in correspondence with each valve position, and the through hole is connected to the pump gear 8a.

It communicates with the suction side and discharge side of the gear pumps 8b and 8c, respectively. That is, as shown in FIG. 9, the discharge side (high pressure side) of the gear pump with respect to the pump gear 8a is Hl, the suction side (low pressure side) is Ll, and the discharge side (high pressure side) of the gear pump with respect to the pump gear 8b is Hl. is H2, which is the suction side (low pressure side) beam, and the discharge side (high pressure side) of the gear pump related to the pump gear 8C is H8, which is the suction side (low pressure side) beam. Grooves 28a, 28b, 28c
, 28d, 28e, and 28f communicate with the above H++Lr+Hz+L-, H-, and Ls via check valves 29, respectively.

The operation of this embodiment is basically the same as that of the first embodiment, and only the flow of hydraulic oil from the first hydraulic oil reservoir 14 to the gear pump low pressure side is different. That is, in this embodiment, hydraulic oil does not flow from the high pressure side of the gear pump to the passage 27 in the distributor main body due to the action of the check valve (the pressure on the low pressure side of the gear pump and the operation in the hydraulic oil reservoir 14 When the difference between the oil pressure and the oil pressure exceeds a predetermined value, the check valve causes the hydraulic oil to flow from the hydraulic oil reservoir to the low pressure side of the gear pump.The predetermined value is determined by the characteristics of the check valve.

In this embodiment, the same effect is performed even when the rotation directions of the input rotation shaft and the output rotation shaft are reversed. Further, in this embodiment, the hydraulic oil is directly supplied from the hydraulic oil reservoir to the lowest pressure part, which is efficient. Furthermore, in this embodiment, the hydraulic oil is circulated from the hydraulic oil reservoir through a long groove relatively close to the surface, which is advantageous for cooling the hydraulic oil.

In the above two embodiments, 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 bypass route may be formed as the communication path. Desired operating characteristics can be obtained by adjusting the cross-sectional area of the bypass route.

Furthermore, it goes without saying that similar effects can be obtained even if the input rotation axis and the output rotation axis are reversed in the above embodiments.

[Effect of the invention] As explained above, according to the present invention, full-time 4WD
It can be well adapted to the drive power transmission system that distributes drive power to the front and rear wheels of automobiles, and there is little occurrence of braking phenomena (it generates little heat, even when the difference between the output shaft rotation speed and the human power shaft rotation speed is large). A novel rotational force transmission mechanism with sufficiently large transmission force is provided.

In addition, in the present invention, the pump gear is eccentrically attached to the first rotating shaft, and a ring gear that meshes with the pump gear is attached to the second rotating shaft to increase the rotation speed of the pump gear, so that the gear pump can be effectively operated. Furthermore, desired operating characteristics can be easily achieved by appropriately setting the ratio of the number of teeth between the pump gear and the ring gear.

Furthermore, the present invention is provided with a mechanism for supplying the hydraulic oil in the hydraulic oil reservoir to the non-high pressure side of the gear pump, thereby increasing the overall pressure while maintaining the pressure difference in the gear surface running space. This allows for stable operation without causing vapor lock on the low pressure side even if the flow of hydraulic oil from the high pressure side to the low pressure side via the hydraulic oil communication passage is insufficient.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing a first embodiment of the rotational force transmission mechanism according to the present invention, FIG. 2 is a perspective view showing its assembled state, and FIGS. 3 and 4 are sectional views thereof. It is. FIG. 5 is a schematic diagram showing a driving force transmission system of a 4WD vehicle using the rotational force transmission mechanism of this embodiment. FIG. 6 is an exploded perspective view showing a second embodiment of the rotational force transmission mechanism according to the present invention, FIG. 7 is a perspective view showing its assembled state, and FIGS. 8 and 9 are sectional views thereof. and
FIG. 10 is a partial sectional view thereof. 2: Input rotating shaft, 2': Input rotating shaft rotation center, 4: Output rotating shaft, 4': Output rotating shaft rotation center, 5: Pump gear support member, 6a, 6b, 6c: Pump gear rotating shaft. 8a, 8b, 8c: pump gear, lO: internal casing, 11.13: groove, 14, f4a ~ 14d: hydraulic oil reservoir, 15, 15a-
15d: Piece, 16: External casing, 18: Ring gear, 20 Nibrate, 22: Hydraulic oil distributor body, 24.26: Hydraulic oil distributor plate. 28a to 28f: groove, 29: check valve, 56: rotational force transmission mechanism. Figure 2 2゜ Figure 3 Figure 7 Figure 8

Claims (4)

[Claims] (1) A first rotating shaft and a second rotating shaft are arranged coaxially and oppositely, and an internal casing is attached to an end of the first rotating shaft, and the internal casing has the above-mentioned A pump gear is rotatably supported around an axis eccentric from and parallel to the rotation center of the first rotation shaft, and an external casing is attached to an end of the second rotation shaft. A ring gear that meshes with the pump gear is formed on the inner surface of the outer casing, and the inner casing and the outer casing cooperate to seal at least the gear surface running space of the pump gear and ring gear, and the gear surface The running space is filled with hydraulic oil, the gear surface running spaces on both sides of the contact position between the pump gear and the ring gear communicate with each other through a path with a small cross section, and the internal casing has a space that communicates with the gear surface running space. A rotational force transmission for a 4WD vehicle, characterized in that a hydraulic oil reservoir is provided, and a mechanism is provided for supplying the hydraulic oil in the hydraulic oil reservoir to the non-high pressure side of the gear surface running space. mechanism. (2) The 4W according to claim 1, wherein the hydraulic oil reservoir is provided with hydraulic oil pressurizing means using a spring as a mechanism for supplying the hydraulic oil to the non-high pressure side in the gear surface running space.
D Rotational force transmission mechanism for automobiles. (3) As a mechanism for supplying the hydraulic oil to the non-high pressure side in the gear surface running space, communication passages are provided between the hydraulic oil reservoir and each of the non-high pressure side and the high pressure side in the gear surface running space. 4 according to claim 1, wherein the communication path is provided with a check valve that allows flow only to the non-high pressure side.
Rotational force transmission mechanism for WD cars. (4) The rotational force transmission mechanism for a 4WD vehicle according to claim 1, wherein a plurality of the pump gears are provided, and these are arranged at rotationally symmetrical positions with respect to the center of rotation of the first rotating shaft.