JPH03134360A - Torque transmission mechanism for four-wheel drive automobile - Google Patents

Abstract

PURPOSE:To obtain desired operation properties by attaching a bump gear eccentrically to an input rotary shaft and increasing the number of revolutions of the pump gear, and also setting tooth-number ratio of the pump gear to a ring gear properly. CONSTITUTION:Pump gears 8a-8c are attached eccentrically to an input rotary shaft 2, and a ring gear 18 engaging with the pump gears 8a-8c are attached to an output rotary shaft 4 so as to increase the number of revolutions of the pump gears, and also the tooth-number ratio of the pump gears 8a-8c to the ring gear 18 is set properly. Hereby, desired operating properties can be obtained easily, and heat generation becomes small, and enough great transmitting force can be obtained even if the difference between the number of output revolutions and the number of input revolutions 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 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 directly connected wheel slips on the road surface for some reason, a difference occurs between the engine side rotation speed and the wheel side rotation speed in the rotational force transmission mechanism, and the wheel side rotation speed is adjusted based on this difference. The driving force is transmitted through fluid so as to match the engine speed.

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) There is a considerable amount of energy loss, the amount of heat generated is relatively large, and the performance deteriorates significantly due to a rise in the temperature of the fluid, so it is said to be unsuitable for long-term off-road driving, such as on sandy terrain.

(b) Even if the difference in rotational speed between the input side and the output side is relatively large, the transmitted force will not be that 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 power to the front and rear wheels of a full-time 4WD vehicle, and generates less heat (output shaft rotation speed and input shaft rotation speed It is an object of the present invention to provide a novel rotational force transmission mechanism in which the transmission force is sufficiently large even when the difference between the rotational force and the rotational force 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. A sun gear is supported on the inner casing and is rotatably engaged with the pump gear around the center of rotation of the first rotating shaft, and an outer casing is supported on the end of the second rotating shaft. is attached, and a ring gear that meshes with the pump gear is formed on the inner surface of the outer casing, and the inner casing and outer casing cooperate to reduce the gear surface running space of the pump gear, sun gear and ring gear. These gear surface running spaces are filled with hydraulic oil, and the gear surface running spaces on both sides of the contact position between the pump gear and sun gear communicate with each other through a path with a small cross-section. There is provided a rotational force transmission mechanism for a 4'WD automobile, characterized in that the gear surface running spaces on both sides of the contact position with the ring gear are communicated through a path with a small cross section.

In the present invention, a hydraulic oil reservoir may be provided that communicates with the gear surface running space, and a mechanism may be provided for supplying the hydraulic oil in the hydraulic oil reservoir to the low pressure side of the gear surface running space.

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. In this case, the high pressure side of the gear surface running spaces on both sides of the contact point between the pump gear and the sun gear is communicated with the high pressure side of the gear surface running spaces on both sides of the contact point between the pump gear and the ring gear adjacent to the pump gear. , the low pressure side of the gear surface running spaces on both sides of the contact position between the pump gear and the sun gear may be communicated with the low pressure side of the gear surface running spaces on both sides of the contact position between the pump gear and the ring gear adjacent to the pump gear. can.

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

FIG. 1 is an exploded perspective view showing an 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. .

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 support member 5 is fixed to the end of the input rotation shaft 2 and 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 6a to 6C are arranged rotationally symmetrically at angular intervals of 120 degrees about the input rotating shaft rotation center 2'. Further, one end of a sun gear rotation shaft 6d coaxial with the input rotation shaft rotation center 2' is attached to the support member 5. Equivalent pump gears 8a, 8b, and 8C are rotatably attached to the rotating shafts 6a, 6b, and 6C, respectively, and a sun gear 8d is rotatably attached to the rotating shaft 6d. They mesh with 8a, 8b, and 8c, respectively. The support member 5 also includes an internal casing 10 a +
10b+10c is fixed. These internal casings are formed with cylindrical inner wall surfaces on which the tips of the teeth of the pump gears 8a, 8b, 8c and sun gear 8d are very close to each other.

On the other hand, an external casing 16 is fixed to the end of the output rotating shaft 4. The outer casing includes the support member 5, rotating shafts 6a to 6d, pump gears 8a to 8c, and sun gear 8d.
It has a cylindrical shape that covers the inner casings 10a to 10loc, 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. And the inner casing 10a~
The outer peripheral surface of the ring gear 10c is a cylindrical surface adjacent to the tip of the ring gear 18.

12 is a spacer ring. Reference numeral 20 denotes a plate attached to the outer casing 16 from the outside of the support member 5, thereby sealing the support member 5, rotating shafts 6a to 6d, pump gears 8a to 8c, sun gear 8d, and inner casings 10a to 10c. has been done.

With the above configuration, the internal casings 10a to 10c
and the outer casing 16, the pump gear 8a
~8C can be rotated relative to each other while meshing with the ring gear 18 and the sun gear 8d, and
, the rotating shafts 6a to 6d, the pump gears 8a to 8c, the sun gear 8d, the inner casings LOa to 10c, the outer casing 16, and the plate 20 are relative to each other around the input rotating shaft rotation center 2' and the output rotating shaft rotation center 4'. It can rotate. The space between the inner casings 10a to 10c and the outer casing 16 is filled with hydraulic oil.

22 is a hydraulic oil reservoir, which is also filled with hydraulic oil. The hydraulic oil reservoir can communicate with the space between the outer casing 16 and the inner casings 10a to 10c via a check valve 24.

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.

Although not shown in Fig. 5, 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, which constitutes the front wheel drive system. has been done. 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 above embodiment, and the output rotation shaft 4 of the mechanism is transmitted via the rear differential 32. and is connected to the rear wheels 34, thereby forming a rear wheel drive system.

In this embodiment, when the input rotating shaft 2 rotates according to the driving force from the engine, the pump gear rotating 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. 4, and the sun gear 8d is accordingly rotated in the direction of the arrow around the rotating shaft 6d. As a result, in each gear pump configured to include each pump gear 8a, 8b, 8c, ring gear 18 or sun gear 8d, support member 5, inner casings 10a to loc, and outer casing 16, the position where each pump gear and ring gear mesh or A pressure difference occurs in the gear surface running space on both sides of the position where each pump gear and sun gear mesh. In FIG. 4, H is the high pressure side and L is the low pressure side.

As shown in Figure 4, each pump gear (e.g. 8a
), the high pressure side space H on one side where the ring gear 18 meshes with the high pressure side space H on one side where the adjacent pump gear (for example 8C) and the sun gear 8d mesh are communicated by a small hole 26.

Similarly, each pump gear (e.g. 8a) and ring gear 18
A small hole 28 communicates with a low-pressure side space on one side at a position where the two gears mesh with each other and a low-pressure side space on one side at a position where the adjacent pump gear (for example, sb) and the sun gear 8d mesh with each other.

By the way, in such a structure, hydraulic oil generally leaks to some extent from the high pressure side to the low pressure side through a gap between the gear and the casing. Therefore, when the input rotating shaft 2 starts rotating from a state where both the human-powered rotating shaft 2 and the output rotating shaft 4 are stopped, if the rotational speed of the input rotating shaft is relatively small, the high pressure The pressure difference between the side and the low pressure side is
It is realized once, and sufficient leakage occurs during this time. As a result, pump gears 8a, 8b, 8c and sun gear 8d
The ring gear 18, which is engaged with the pump gear, rotates around the rotating shafts 6a, 6b, 6c, and 6d, respectively.
The outer casing 16 and the output rotating shaft 4 are formed of
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
and sun gear 8d, ring gear 18 and internal casing 10
a to 10c and the outer casing 16 are in a fixed state, and the rotational force of the input rotating shaft 20 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 It rotates around the output rotation shaft 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, 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 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 30 is almost unloaded. operate in the state.

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 is greater than the rotational speed of the output rotational shaft 4 (the rotational speed of the input rotational shaft 2 is greater than the rotational speed of the output rotational shaft 4 due to the outlet block effect of the gear pump). The force is transmitted to the output rotating shaft 4, the rotational force is transmitted to the rear wheel 34, and the rotational speed of the output rotating shaft 4 is thus controlled to approach the rotational speed of the input rotating shaft 2.

In this embodiment, the check valve 24 provided between the hydraulic oil reservoir 22 and the gear surface running space prevents hydraulic oil from flowing into the hydraulic oil reservoir 22 from the high pressure side space H. Hydraulic oil flows from the hydraulic oil reservoir 22 to the low pressure side space. In this way, in this embodiment, the hydraulic oil reservoir 2
Since hydraulic oil is supplied directly from 2 to the lowest pressure part,
Stable operation is possible without paper lock on the low pressure side, making it efficient.

In addition, in this embodiment, the pump gear is mounted eccentrically from the rotation center 2' of the input rotation shaft to increase the rotation speed of the pump gear, so that the gear pump can be operated effectively. Desired operating characteristics can be easily achieved by appropriately setting the ratio of the number of teeth.

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 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
A new rotational power transmission system that can be applied well to the drive power transmission system that distributes the driving force to the front and rear wheels of automobiles, generates little heat, and has a sufficiently large transmission force even when the difference between the output shaft rotation speed and the input shaft rotation speed is large. A mechanism is provided.

Furthermore, 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, since the present invention is provided with a sun gear that meshes with all pump gears, the number of gear pumps is large and the efficiency is high.
Therefore, large driving force transmission is possible.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an 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. . 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. 2: Input rotating shaft, 2' center of rotation of two-man power rotating shaft, 4: output rotating shaft, 4': center of rotation of output rotating shaft, 5: support member, 6a to 6d: gear rotating shaft, 8a to 8c: pump gear, 8d : Sun gear, 10a to 10c: Internal casing, 12 spacer ring, 16: External casing, 18: Ring gear, 2o nibrate, 22: Hydraulic oil reservoir, 24: Check valve, 26.28: Small hole, 30: Rotating force transmission mechanism.

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 the pump gear is rotatably supported around the rotation center of the first rotation shaft. A sun gear rotatably engaged with the pump gear is supported, an outer casing is attached to an end of the second rotating shaft, and a ring gear is formed on the inner surface of the outer casing, and the ring gear engages with the pump gear. The inner casing and the outer casing work together to seal at least the gear surface running spaces of the pump gear, sun gear, and ring gear, and these gear surface running spaces are filled with hydraulic oil, and the pump gear and sun gear The gear surface running spaces on both sides of the contact point between the pump gear and the ring gear communicate with each other through a small cross-section path, and the gear surface travel spaces on both sides of the contact point between the pump gear and the ring gear communicate with each other through a small cross-section path. A rotational force transmission mechanism for 4WD vehicles. (2) A hydraulic oil reservoir is provided that communicates with the gear surface running space, and a mechanism is provided for supplying the hydraulic oil in the hydraulic oil reservoir to the low pressure side of the gear surface running space. The rotational force transmission mechanism for a 4WD vehicle according to claim 1. (3) The rotational force transmission mechanism for a 4WD vehicle according to claim 1 or 2, 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. (4) The high-pressure side of the gear surface running spaces on both sides of the contact point between the pump gear and the sun gear communicates with the high-pressure side of the gear surface running spaces on both sides of the contact point between the pump gear and the ring gear adjacent to the pump gear. The low pressure side of the gear surface running spaces on both sides of the contact position between the pump gear and the sun gear communicates with the low pressure side of the gear surface running spaces on both sides of the contact position between the pump gear and the ring gear adjacent to the pump gear. The rotational force transmission mechanism for a 4WD vehicle according to claim 3.