JPH1047455A - Torque-sensitive coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer the driving force of an engine to the front and the rear wheels in running straight when used in a four-wheel drive vehicle. SOLUTION: A pair of side gears 2 and 3 composed of helical gears are rotatably arranged on the axis L of a housing 1. Thrust washers 5, 6 and 7 are supported on the housing 1 not to rotate between the housing 1 and the side gear 2, the side gears 2 and 3, and the housing 1 and the side gear 3 respectively. An idle gear 4 meshing with the side gears 2 and 3 is rotatably arranged inside a pocket 1d in the housing 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coupling used for transmitting a driving force of an engine of a four-wheel drive vehicle to front wheels and rear wheels.

[0002]

2. Description of the Related Art Conventional couplings of this type include:
There is a rotational speed difference sensitive type coupling. The rotational speed difference sensitive type coupling includes a housing, a rotor rotatably supported by the housing, and a hydraulic mechanism provided between the housing and the rotor. Then, a torque corresponding to the relative rotation speed (difference in rotation speed) is transmitted between the housing and the rotor (Japanese Patent Laid-Open No. 15942/1990).
No. 3). When the rotational speed difference sensitive coupling configured as described above is used for a four-wheel drive vehicle, for example, the engine and the front wheels are connected to the housing, and the rear wheels are connected to the rotor.

[0003]

In a rotational speed difference-sensitive coupling, torque is not transmitted between the housing and the rotor unless there is a rotational speed difference between the housing and the rotor. Therefore, in a four-wheel drive vehicle using the rotational speed difference-sensitive coupling, torque cannot be transmitted to the rear wheels when the front wheels and the rear wheels are rotating at a constant speed. For this reason, when the vehicle travels straight, there is a problem that the vehicle can function only as a two-wheel (front wheel) drive vehicle in spite of being a four-wheel drive vehicle.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention according to claim 1 comprises a housing, a pair of side gears rotatably provided on an axis in the housing, and a housing. A pinion gear that is rotatably and non-revolvably supported and has first and second gear portions that mesh with the pair of side gears; at least one of the side gear and the pinion gear and the housing include a side gear and a pinion gear; And a frictional contact surface which is brought into pressure contact with each other by a force generated by meshing with the gear and generates frictional resistance for preventing rotation of the one gear. In this case, the housing is formed in a cylindrical shape, and a housing recess for rotatably housing the pinion gear is formed in an inner circumferential surface of the cylindrical housing, and an inner circumferential surface of the housing recess and an outer circumferential surface of the pinion gear are formed. Are preferably frictional contact surfaces which are brought into pressure contact with each other by a force to the outside of the housing generated by the engagement of the side gear and the pinion gear. In addition, at least one of the pair of side gears and the first or second gear portion of the pinion gear meshing with the pair of side gears are helical gears,
The end surface of the one side gear and the contact surface provided on the housing and pressed against the end surface of the one side gear by a thrust force generated by the engagement of the one side gear and the pinion gear are the friction contact surfaces. It is desirable.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 (A),
(B) and FIG. 2 show an embodiment of the present invention, and a torque-sensitive coupling (hereinafter, may be simply referred to as a coupling) A shown in these figures.
Comprises a housing 1, a pair of two side gears 2, 3,
At least one (three in this embodiment) idle gear 4 is provided.

The housing 1 is composed of a cylindrical housing body 1A having one end opened and a bottom 1a at the other end, and a lid 1B closing one end opening of the housing body 1A. The main body 1 and the lid 1B are fixed by bolts 1C. A spline hole 1b extending on the axis L of the housing 1 is formed in the bottom 1a of the housing body 1A. In the lid 1B,
A through hole 1c extending on the axis L is formed.

Inside the housing 1, a pair of side gears 2 and 3 are arranged rotatably on the axis L.
The pair of side gears 2 and 3 have the same gear specifications such as a module, the number of teeth, and a pressure angle, but may have different gear specifications. In this embodiment, helical gears are used as the side gears 2 and 3, but spur gears may be used. When a helical gear is used, the twisting directions of the side gears 2 and 3 may be the same or may be opposite to each other. The side gears 2 and 3 are formed with spline holes 2a and 3a, respectively.

[0008] Between the side gear 2 and the bottom 1a, between the side gears 2 and 3, and between the side gear 3 and the lid 1A,
Thrust washers 5, 6, 7 are arranged respectively. The thrust washers 5, 7 are directly non-rotatably supported by the housing 1. On the other hand, thrust washer 6
Are engaged with the idle gear 4 and are non-rotatably supported by the housing 1 via the idle gear 4, as shown in FIG.

On the inner peripheral surface of the housing body 1A, a pocket (housing recess) 1d having a substantially 断面 circular cross section is formed extending from the opening to the bottom 1a in parallel with the axis L. A plurality of pockets 1d (6 in this embodiment)
One), but only one may be formed. The six pockets 1d are arranged at equal intervals in the circumferential direction,
The idle gear 4 is rotatably (rotated) accommodated in three pockets 1d arranged every other in the circumferential direction. The remaining three pockets 1d are used as lubricating oil reservoirs. However, when the torque input to the side gear 2 is large, the remaining three pockets 1d are used.
The idle gear 4 may also be accommodated in d.

The idle gear 4 is shaped like a shaft having a circular cross section. One end of the idle gear 4 is a first gear that meshes with the side gear 2.
And a second gear portion 4b meshing with the side gear 3 is formed at the other end. 1st, 2nd
The gear portions 4a, 4b are formed with the same gear specifications in correspondence to the side gears 2, 3 having the same gear specifications. Moreover, both are formed as a continuous and integral gear. Of course, when the gear specifications of the side gears 2 and 3 are different from each other, the first and second gears 4a and 4b also have different gear specifications and are separately formed.

Next, the operation of the coupling A having the above-described configuration will be described with reference to an example in which the coupling A is used in a four-wheel drive vehicle. FIG. 3 shows a schematic configuration of a drive system of the vehicle in which the coupling A is used, the side gears 2 is coupled to the engine E through the input shaft S ₁ fitted to the spline hole 2a, the side gears 3 is a through hole 1c of the lid 1B.
And the hollow output shaft S fitted into the spline hole 3a
The front wheel W _F through _2, is connected to the front wheel differential gear unit D _F for W _F, the housing 1, the rear wheel W _R through the output shaft S ₃ fitted to the spline hole 1b, a W _R It is connected to the wheel-side differential gear unit D _R after. The input shaft S ₁ is through disposed in the hollow in the output shaft S _2.

When the side gear 2 is driven to rotate by the engine E, the rotation is transmitted to the side gear 3 via the idle gear 4. Therefore, the side gear 3 is substantially directly connected to the engine E, always the front wheel W _F when the engine E rotates, W _F is rotated.

When the side gear 2 is driven to rotate,
As shown in FIG. 4, a pressing force F _{1 in the} direction indicated by the solid line is applied to the idle gear 4 by meshing with the side gear 2. Similarly, it acts pushing force F ₂ in the arrow direction indicated by a broken line by meshing into the side gears 3. The idle gear 4 is pushed toward the outside of the housing 1 by the resultant force F of these pushing forces F ₁ and F ₂ , and is brought into pressure contact with the outside portion of the inner peripheral surface of the pocket 1 d. As a result, a frictional resistance is generated between the outer peripheral surface of the idle gear 4 and the inner peripheral surface of the pocket 1d so as to prevent the idle gear 4 from rotating. As a result, a rotational torque corresponding to the frictional resistance is transmitted to the housing 1. Therefore, the rear wheels W _R ,
The W _R, they wheel W _F, even if rotated in the W _F and the same speed rotational torque is transmitted. Therefore, the vehicle equipped with the coupling A of the present invention functions as a four-wheel drive vehicle even when traveling straight. As is clear from this content,
The outer peripheral surface of the pinion gear 4 and the inner peripheral surface of the pocket 1d are friction contact surfaces. The same applies when the side gear 2 is rotationally driven in the direction opposite to the direction of the arrow in FIG.

Here, the frictional resistance acting between the idle gear 4 and the housing 1 is proportional to the magnitude of the resultant force F,
The resultant force F is proportional to the rotational torque transmitted to the side gear 2. Thus, the magnitude of the torque transmitted the rear wheel W _R, the W _R is proportional to the magnitude of the rotational torque, i.e. the input torque transmitted to the side gears 2. Assuming that the magnitude of the input torque is constant, the frictional resistance acting between the idle gear 4 and the housing 1 is determined by the coefficient of friction between the contact surfaces and the magnitude of the resultant force F. Changes according to the engagement pressure angle between the side gears 2 and 3 and the idle gear 4. Therefore, by appropriately adjusting the friction coefficient and the engagement pressure angle, the rear wheel W _R
You can change the magnitude of the torque transmitted to, thereby it is possible to adjust the ratio between the torque transmitted to the front wheels W _F rear wheel and torque transmitted to W _R.

[0015] In the coupling A of this embodiment, because of the use of helical gears as the side gears 2,3 and the idle gear 4, it is possible to further increase the torque transmitted to the rear wheel W _R . That is,
When a helical gear is used as the side gears 2, 3 and the idle gear 4, a thrust force directed in the direction of the axis L is applied to the side gears 2, 3 and the idle gear 4 by meshing with each other. When the torsional directions of the side gears 2 and 3 are the same as in this embodiment, as shown in FIG. 5, when the side gear 2 is driven to rotate in the direction of the arrow A shown by the solid line, the side gears 2 and 3 are rotated. , Thrust forces F ₃ and F ₄ acting to make them approach each other act on each other,
The end faces of the side gears 2 and 3 are pressed against the thrust washer 6 by the thrust force. Then, by the friction resistance acting between the end face and the thrust washer 6 of each side gears 2 and 3, the torque is transmitted from the side gears 2 and 3 the housing 1, the torque is transmitted to the rear wheel W _R therefore. On the other hand, when the side gear 2 is driven to rotate in the direction of the arrow B shown by the broken line, thrust forces F ₃ ′ and F ₄ ′ acting to separate the side gears 2 and 3 from each other act on the side gears 2 and 3, respectively. Are thrust washers 5,7
Pressed to. Then, torque is transmitted from the side gears 2 and 3 to the housing 1 due to frictional resistance acting between them. As is clear from this, the end faces of the side gears 2, 3 and the thrust washers 5, 5
The end faces 6 and 7 are friction resistance surfaces. This is the same in the case of FIG. 6 described later. The idle gear 4
Generates thrust due to meshing with the side gears 2 and 3, and the thrust forces act in directions to cancel each other.

The point that the torque transmitted to the housing 1 can be increased is the same as when the twisting directions of the side gears 2 and 3 are opposite to each other.
When the twisting direction of the side gear 3 is reversed, as shown in FIG. 6, when the side gear 2 is driven to rotate in the direction of arrow A, the side gears 2 and 3
Acting thrust force F _5, F ₆ toward the side, respectively, side gears 2 is pressed against the thrust washer 6, the side gears 3 is pressed against the thrust washer 7. Then, torque is transmitted from the side gears 2 and 3 to the housing 1 by frictional resistance acting between them. In this case, the side gears 3, as apparent from FIG. 6, since the thrust force (F ₅ + F ₆₎ is applied, it is possible to increase the frictional resistance acting between the side gear 3 and the thrust washer 7, Thereby, the torque transmitted to the housing 1 can be further increased. This applies to the case where the side gear 2 is driven to rotate in the direction of arrow B. Note that the idle gear 4, the engagement of the side gears 2 and 3, although a thrust force F ₅ + F ₆ is applied, the thrust force is supported by the bottom 1a or the cover 1A idle gear 4 is pressed. Moreover, the torque transmitted to the housing 1 can be increased by the frictional resistance acting between the idle gear 4 and the bottom 1a or the lid 1A. Therefore, the end surface of the idle gear 4 and the respective surfaces of the bottom portion 1a and the lid 1A against which the idle gear 4 is pressed are also friction contact surfaces.

Further, since the torque transmitted to the housing 1 has a magnitude corresponding to the frictional resistance acting between the side gears 2, 3 and the washers 5, 6, 7, the friction as the washers 5, 6, 7 By preparing various types with different coefficients and selecting and using them as appropriate,
The magnitude of the torque transmitted to the housing 1 can be adjusted.

The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example,
In the above embodiment, the housing 1 is connected to the rear wheel W _R
Connected to, but are connected to the side gears 3 to the front wheel W _F,
As shown in FIG. 7, to connect the housing 1 to the front wheel W _F,
Side gears 3 may be connected to the rear wheel W _R a.
Also, connect the side gear 3 to the engine E, connect the side gear 2 to the front wheel W _F or the rear wheel W _R, may be connected to the housing 1 to the rear wheel W _R or the front wheel W _F. Further, although the thrust washers 5 and 7 are fixed to the housing 1, they may be fixed to the side gears 2 and 3 or may not be fixed to any of them. When the thrust washers 5, 7 are not fixed to either the housing 1 or the side gears 2, 3, the thrust washers 5, 7
Rotates integrally with one of the side gears 2, 3 and the housing 1 having a larger frictional resistance, and comes into sliding contact with the other. Further, the thrust washer 6 may be integrally rotated with the side gears 3 without being fixed to the housing 1. In such a case, the torque transmitted to the housing 1 can be greatly changed between when the side gear 2 is driven to rotate in the direction of arrow A and when the side gear 2 is driven to rotate in the direction of arrow B.

[0019]

As described above, according to the first aspect of the present invention, when the coupling according to the present invention is used in a four-wheel drive vehicle, the front wheels and the rear wheels rotate at the same speed. Even when it is present, the rotational torque can be transmitted to the front wheels and the rear wheels. Therefore, the function as a four-wheel drive vehicle can be sufficiently exhibited even when traveling straight. In addition, a torque corresponding to the input torque from the engine can be transmitted to the front wheels or the rear wheels connected to the housing. According to the second aspect of the present invention, since the outer peripheral surface of the idle gear and the inner peripheral surface of the pocket accommodating the idle gear are friction contact surfaces, it is not necessary to separately form a friction contact surface. Manufacturing costs can be reduced. Further, according to the third aspect of the present invention, the direction in which the thrust force acts differs between the case where the side gear is driven to rotate in one direction and the case where the side gear is driven to rotate in the other direction. Can be changed.

[Brief description of the drawings]

FIG. 1 is a view showing a torque-sensitive coupling according to the present invention, wherein FIG. 1 (A) is a cross-sectional view taken along line AA of FIG. 1 (B),
FIG. 1B is a cross-sectional view taken along the line BB of FIG.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a schematic configuration diagram showing an example of a driving force transmission system of a four-wheel drive vehicle using the torque-sensitive coupling according to the present invention.

FIG. 4 is a diagram showing a pressing force that acts on an idle gear toward the outside of a housing by engagement of a side gear and an idle gear.

FIG. 5 is a diagram illustrating an example of a thrust force acting on each of the side gear and the idle gear due to meshing between the side gear and the idle gear.

FIG. 6 is a diagram illustrating another example of a thrust force acting on each of the side gear and the idle gear due to meshing between the side gear and the idle gear.

FIG. 7 is a schematic configuration diagram showing another example of a driving force transmission system of a four-wheel drive vehicle using the torque-sensitive coupling according to the present invention.

[Explanation of symbols]

 A Torque-sensitive coupling 1 Housing 1d Pocket (housing recess) 2 Side gear 3 Side gear 4 Idle gear 5 Thrust washer 6 Thrust washer 7 Thrust washer

Claims (3)

[Claims] 1. A housing, a pair of side gears rotatably provided on an axis in the housing, and first and second gears rotatably and non-revolvingly supported by the housing and engaged with the pair of side gears. A pinion gear having a gear portion, and at least one of the side gear and the pinion gear and the housing are pressed against each other by a force generated by meshing of the side gear and the pinion gear to rotate the one gear. A torque-sensitive coupling having a friction contact surface for generating frictional resistance to be prevented. 2. The housing has a cylindrical shape, and a housing recess for rotatably housing the pinion gear is formed on an inner circumferential surface of the cylindrical housing, and an inner circumferential surface of the housing recess and an outer circumference of the pinion gear are formed. The torque-sensitive coupling according to claim 1, wherein the surface is a friction contact surface that is brought into pressure contact with each other by an external force generated by engagement of the side gear and the pinion gear. . 3. A helical gear, wherein at least one of the pair of side gears and a first or second gear portion of the pinion gear meshing with the pair of side gears are provided as a helical gear, and are provided on an end surface of the one side gear and the housing. The torque according to claim 1 or 2, wherein a contact surface against which an end surface of the one side gear is pressed by a thrust force generated by engagement of the side gear and the pinion gear is the friction contact surface. Sensitive coupling.