JP3207450B2 - Transfer of four-wheel drive vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer for distributing the driving force of an engine to a front wheel and a rear wheel differential in a four-wheel drive vehicle.

[0002]

2. Description of the Related Art In a vehicle, when a vehicle turns around a tight corner with four wheels connected directly, a front wheel that tries to turn faster due to a difference in turning radius between the front and rear wheels slips,
A phenomenon occurs as if the brakes were applied.

In order to eliminate such a braking phenomenon, in a conventional four-wheel drive vehicle, a center differential is provided on a drive path separately from the differential of the front and rear wheels to absorb a rotational difference between the front and rear wheels. In the case of a center differential having a mechanical structure, when one of the wheels spins due to derailing or the like, the driving force flows only to that wheel, and there is a problem that it is not transmitted to the other grounded wheels at all.

For this reason, recently, a center differential having a differential function capable of absorbing a rotational difference between the front and rear wheels and a function of limiting the differential function when the wheel spins has been developed. As typical examples, a viscous coupling utilizing the shear resistance of a highly viscous substance and a coupling utilizing the frictional force of a multi-plate clutch and an elastic member are known.

[0005] However, all of the couplings represented by such viscous couplings utilize the speed difference between the input side and the output side for torque transmission, so that torque transmission in a low speed region is almost expected. However, there is a disadvantage that it is difficult to obtain a sufficient driving force.

Further, in order to obtain a large transmission torque in a low speed range, it is necessary to increase the capacity of the coupling due to the use of viscous resistance and frictional force. When trying to cope with the shortage of the transmission torque by using the fluid or the like, there is a problem that a large drag torque is easily generated at the time of turning at a low speed.

Accordingly, the present invention provides a transfer capable of efficiently transmitting a large driving force by a mechanical structure, and realizing a full-time, directly-coupled four-wheel drive without using the center differential as described above. The purpose is.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an input shaft connected to a transmission of an engine and an output shaft connected to a differential of a rear wheel, which are rotatably arranged coaxially. A rotating retainer is provided between the input shaft and an opposing surface of the outer ring rotatably fitted to the outer periphery of the retainer, and a pocket provided in the retainer is provided with a forward and reverse direction of the retainer and the input shaft. A roller as an engaging element that engages with the opposing surface by relative rotation, and an elastic member that holds the roller at a position that does not engage with the opposing surface is incorporated.
The retainer and the output shaft are rotatably connected to the input shaft via a gap in the rotation direction, and a holding member for elastically holding the output shaft and the input shaft at a neutral position of the gap in the rotation direction is provided. The outer wheel has a structure in which a connection portion with a drive shaft connected to the differential of the front wheel is provided.

[0009]

In the above structure, when a rotation difference occurs between the input shaft and the output shaft due to the rotation of the input shaft, the elastic member is deformed and the retainer and the input shaft move relative to each other. Between the opposing surfaces of. For this reason, the front wheels are driven via the outer wheels, and the rear wheels are driven via the output shaft, and a four-wheel drive state is established.

On the other hand, if the rotation of the front wheel exceeds the rotation of the rear wheel due to turning of a tight corner or the like, the rotation of the outer wheel becomes faster than that of the input shaft and overruns the engaging element. For this reason, the front wheel rotates while being separated from the rear wheel. Ma
Another invention is an engine transmission.
Input shaft connected to the rear wheel differential
The output shaft is rotatably arranged on the same axis as the input shaft.
And the outer ring that is rotatably fitted to the outer circumference
, A rotatable control cage and a fixed
A cage is provided, and control is provided in the pockets provided in both cages.
Forward and reverse phases of the cage and the fixed cage fixed to the input shaft
A slide as an engagement element that engages with the opposing surface by counter-rotation
A plug and a position where the sprag is not engaged with the above-mentioned facing surface.
Built-in elastic member to hold the control cage and output shaft
Can rotate coaxially with the input shaft via a rotational gap.
Connect the output shaft and the input shaft with the rotation direction
Provide a holding member that elastically holds at the neutral position of the gap.
Drive shaft connected to outer wheel and front wheel differential
This is a structure in which a connection portion is provided.

[0011]

1 and 2 show a first embodiment of the present invention, and FIG. 3 shows an example in which the transfer of the embodiment is mounted on a drive path of a four-wheel drive vehicle.

In the drive path shown in FIG. 3, B is the engine, C is the transmission, A is the transfer of the embodiment, D is the rear wheel differential, and E is the front wheel differential. As shown in the figure, an input shaft 1 is connected to a transmission C, an output shaft 2 is connected to a rear wheel differential D via a propeller shaft F, and a silent chain G is connected to a drive shaft 4 connected to a front wheel differential E. The outer ring 3 is connected through the outer ring 3.

As shown in FIG. 1, the input shaft 1 is rotatably supported inside the outer race 3 via a pair of bearings 5 and 5, and has a shaft core hole 6 provided at an end of the input shaft 1. The end of the output shaft 2 is rotatably inserted.

As shown in FIG. 2, a square shaft 7 is formed on the distal end surface of the output shaft 2, and a square hole into which the square shaft 7 is loosely fitted is formed at the closed end of the shaft core hole 6 of the input shaft 1. 8 is formed, and a gap X in the rotational direction is provided between the square hole 8 and the square shaft 7.

The outer ring 3 has a silent chain G on its outer diameter surface.
The sprocket ring 9 that engages with is fixed integrally, and the inner diameter surface is formed on the cylindrical surface 10.

A plurality of cam surfaces 11 are formed in the circumferential direction on the outer diameter surface of the input shaft 1 facing the cylindrical surface 10, and between the respective cam surfaces 11 and the cylindrical surface 10, both ends in the circumferential direction are formed. A narrow wedge-shaped space is formed.

Further, between the cylindrical surface 10 and the cam surface 11,
A retainer 12 is rotatably provided, and a roller 14 as an engaging element and an elastic member 15 are incorporated in a pocket 13 provided on the retainer 12 so as to face each cam surface 11. The elastic member 15 is formed of a thin metal piece or the like having a spring force. Both ends of the elastic member 15 protrude into the pocket 13 so that each roller 14 does not engage with the cylindrical surface 10 and the cam surface 11 by elasticity. Hold in position.

On the other hand, a pin 17 which passes through a pin insertion hole 16 formed in the peripheral wall of the input shaft 1 is fixed to the output shaft 2, and both ends of the pin 17 are integrally connected to the retainer 12. .

Further, an elastic ring 18 is incorporated between the pin 17 and the pin insertion hole 16. The elastic ring 18 holds the angular shaft 7 of the output shaft 2 at the neutral position of the gap X in the rotational direction, and holds the angular shaft 7 via the pin 17 when a rotation difference occurs between the input shaft 1 and the output shaft 2. It has the function of rotating the container 12 relative to the input shaft 1.

The first embodiment has the above structure,
Next, the operation will be described.

When rotation is applied to the input shaft 1 from the transmission C while the vehicle is stopped, the elastic ring 18 is deformed because rotation resistance is applied to the output shaft 2 from the rear wheels stopped on the road surface. Output shaft 2 and cage 12
Rotates relative to the input shaft 1. As a result, the roller 14 moves in the circumferential direction and engages with the cylindrical surface 10 and the cam surface 11 to unite the input shaft 1 and the outer ring 3.

For this reason, the rotation of the input shaft 1 is transmitted from the outer wheel 3 to the differential E of the front wheel via the drive shaft 4 to drive the front wheel. In addition, the deformable elastic ring 18
When the elasticity exceeds the rotational resistance applied to the output shaft 2 from the rear wheels, the output shaft 2 rotates together with the input shaft 1, and the front and rear wheels are driven. Therefore, when the vehicle starts, four-wheel drive is performed, and a large driving force is transmitted to the front and rear wheels.

On the other hand, when the vehicle is running straight,
Although the rear wheel and the front wheel rotate, there should be no rotation difference between the input shaft 1 and the output shaft 2. However, in actuality, the vehicle speed drops due to the slip generated between the rear wheel and the road surface, and the transmission C The rotation exceeds the rotation of the output shaft 2. For this reason,
Even during straight running, the rollers 14 are engaged and the front wheels are driven, so that four-wheel drive is performed.

On the other hand, when the front wheel rotates faster than the rear wheel due to turning of a tight corner or the like, the rotation of the outer wheel 3 exceeds the rotation of the input shaft 1 and the outer wheel 3 overruns. For this reason, the roller 14 is pushed in the circumferential direction by contact with the cylindrical surface 10 of the outer ring 3, and the cylindrical surface 10 and the cam surface 11
And the outer ring 3 rotates in a state of being separated from the input shaft 1. Therefore, the vehicle is in a two-wheel drive state in which only the rear wheels are driven, and a braking phenomenon at a tight corner due to a rotation difference between the front and rear wheels is prevented.

In such a two-wheel drive state with rear wheels,
If the rear wheel slips or one of the rear wheels slips off, the vehicle speed decreases, and the rotation of the input shaft 1 catches up with the rotation of the decelerating front wheel (outer wheel 3). For this reason, the roller 14 is engaged with the cylindrical surface 10 and the cam surface 11, and the driving force is transmitted to the front wheels, thereby automatically shifting to four-wheel drive.

In this case, the driving force of the engine is not transmitted according to the speed difference between the front and rear wheels as in a viscous coupling, but is transmitted by mechanical engagement of the engaging element. Full torque is transmitted to the front and rear wheels. For this reason, even when the vehicle travels on rough terrain, such as sand or muddy ground, where slippage is likely to occur, a large driving force is transmitted to the four wheels, and strong running performance can be exhibited.

On the other hand, if one of the front wheels comes off in the four-wheel drive state, no driving force is transmitted to the grounded wheels due to the differential function of the differential E. As a result, an effective driving force is applied to both front wheels. Although not transmitted, the two-wheel drive state by the rear wheels is maintained via the transfer A, so that the running state of the vehicle is stably maintained.

Although the above operation has been described with respect to traveling in one direction of the vehicle, the transmission operates on the input shaft 1.
When the rotation direction applied to the shaft is reversed, the input shaft 1 and the cage 12
Are rotated in the opposite direction, and the roller 14 is rotated between the cylindrical surface 10 and the cam surface 1.
1 at opposite positions. Therefore, the drive can be switched in the same manner in both the forward and backward directions of the vehicle.

As described above, in the structure of the above embodiment, when the rear wheel or the front wheel slips or slips off during traveling, the driving of the four wheels and the two wheels is automatically switched, and the driving state of the vehicle is maintained. You. Further, when the rotation of the front wheels becomes faster than that of the rear wheels due to turning of a tight corner or the like, the front and rear wheels are separated due to overrunning of the clutch. For this reason, the transfer A itself has both the rotation difference absorbing function and the differential lock function, and enables full-time direct-coupled four-wheel drive without using a center differential having a complicated structure such as a viscous coupling. be able to.

FIGS. 4 to 6 show a second embodiment. In this example, the outer diameter surface of the input shaft 20 is formed by a cylindrical surface 23 concentric with the cylindrical surface 22 of the outer race 21, and both cylindrical surfaces 2
Between 2 and 23, a rotatable control holder 24 and a fixed holder 25 fixed to the input shaft 20 are incorporated.

A plurality of pockets 26, 27 are formed in the control holder 24 and the fixed holder 25 in the circumferential direction, and each pocket 26, 27 has a sprag 28 as an engaging element.
And an elastic member 29 are incorporated.

The sprag 28 is, as shown in FIG.
The outer diameter side and the inner diameter side are formed by an arc-shaped surface 30 having a center of curvature on the center line of the sprag. . The elastic member 29 is supported by the control holder 24 and presses the sprags 28 from both sides to press the two cylinders 22, 2
3 is held at a neutral position that does not engage with the third position.

In the above structure, when a rotation difference occurs between the input shaft 20 and the output shaft 2, the control cage 2
4 rotates relative to the fixed retainer 25. For this reason, the sprags 28 are engaged with the cylindrical surfaces 22 and 23, and rotate the outer race 21 in the same direction as the input shaft 20.

Since the structure and operation other than those described above are the same as those of the first embodiment, the same parts are designated by the same reference numerals and their description is omitted.

FIGS. 7 and 8 show a third embodiment. In this example, the input shaft 31 and the output shaft 32 are formed with shaft insertion holes 33 and 34 penetrating both of them, and the elastically deformable torsion bar 35 as a holding member is inserted into the shaft insertion holes 33 and 34. ing. One end of the torsion bar 35 is connected to the input shaft 31 and the other end is connected to the output shaft 32.
The square shaft 36 of the output shaft 32 is held at the neutral position of the gap X in the rotation direction with respect to the square hole 37 of the input shaft 31.

Further, a pin 17 for connecting the output shaft 32 to the holder 12 and a pin insertion hole 16 provided on a peripheral wall of the input shaft 31 are provided.
Between them, there is no elastic ring as in the first embodiment,
Both are fitted with a clearance in the rotation direction.

The other components are the same as in the first embodiment, and the same components are denoted by the same reference numerals and description thereof will be omitted.

In the transfer of the above-described embodiment, when the input shaft 31 rotates and the rotational force does not cause the torsion bar 35 to be twisted, the cylinder of the roller 14 is used.
There is no engagement between the surface 10 and the cam surface 11, and the torque is
Two-wheel drive transmitted to the output shaft 32 via the
It will be a dynamic run.

On the other hand, if the torque of the input shaft 31 is caused to twist the torsion bar 35, the torsion bar 3
5 the input shaft 31 and the retainer 12 rotate relatively twisted large, engage the cylindrical surface 10 and cam surface 11 roller 14 by the rotation moves in the circumferential direction, the output shaft 32 and the outer ring 3
The vehicle is driven by a four-wheel drive that rotates together.

FIGS. 9 and 10 show a fourth embodiment, in which a sprag is used for the engaging element in the structure of the third embodiment. That is, a cylindrical surface 43 concentric with the cylindrical surface 42 of the outer ring 41 is formed on the outer diameter surface of the input shaft 40, and the control cage 44 provided between the two cylindrical surfaces 42, 43.
The sprag 46 and the elastic member 47 are incorporated in each pocket of the fixed retainer 45. The other structure is the same as that of the above-described embodiment, and therefore, the same components are denoted by the same reference numerals and description thereof will be omitted.

[0041]

As described above, the transfer of the present invention
By utilizing the engagement of the mechanical clutch and the effect of overrunning, the transmission direction of the driving force is automatically switched between the front wheel and the rear wheel according to the speed difference between the transmission and the front and rear wheels. And the function of limiting the differential function. Therefore, a full-time, directly-coupled four-wheel drive can be realized with a simple structure without using a center differential.

In addition, since the driving force is transmitted not by utilizing the speed difference between the entrance and exit but by the mechanical engagement by the engaging element, the full torque of the engine is transmitted to the wheels even at low speed running. It can transmit and show strong running power.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a schematic view showing an example of attachment to the vehicle of the above.

FIG. 4 is a cross-sectional view showing a second embodiment.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 is an enlarged sectional view showing a main part of the above.

FIG. 7 is a sectional view showing a third embodiment.

FIG. 8 is a sectional view taken along the line VIII-VIII in FIG. 7;

FIG. 9 is a sectional view showing a fourth embodiment.

FIG. 10 is a sectional view taken along line XX of FIG. 9;

[Explanation of symbols]

 1, 20, 31, 40 Input shaft 2, 32 Output shaft 3, 21, 41 Outer ring 4 Drive shaft 9 Sprocket ring 10 Cylindrical surface 11 Cam surface 12 Cage 14 Roller 15 Elastic member 18 Elastic ring 24, 44 Control retainer 25 , 45 Fixed retainer 28, 46 Sprag 29, 47 Elastic member 35 Torsion bar A Transfer B Engine C Transmission D Rear wheel differential E Front wheel differential

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-241532 (JP, A) JP-A-63-186042 (JP, A) JP-A-54-90837 (JP, U) 11603 (JP, B1) Jikken 49-20040 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60K 17 / 35,23 / 08 F16D 41/08

Claims (2)

(57) [Claims] An outer shaft rotatably fitted coaxially with an input shaft connected to a transmission of an engine and an output shaft connected to a differential of a rear wheel; A roller is provided between the opposing surfaces of the retainer and a roller as an engaging element that engages with the opposing surface by a relative rotation of the retainer and the input shaft in forward and reverse directions in a pocket provided in the retainer. An elastic member that holds the roller at a position that does not engage the opposing surface is incorporated, and the retainer and the output shaft are co-rotatably connected to the input shaft via a clearance in the rotational direction. A transfer for a four-wheel drive vehicle, comprising: a holding member for elastically holding an input shaft at a neutral position in the clearance in the rotational direction; and a connecting portion for connecting the outer wheel to a drive shaft connected to a differential of a front wheel. 2. An outer ring, wherein an input shaft connected to a transmission of an engine and an output shaft connected to a differential of a rear wheel are rotatably arranged coaxially, and the input shaft is rotatably fitted to an outer periphery thereof. A rotatable control retainer and a fixed retainer fixed to the input shaft are provided between opposed surfaces of the control retainer and fixed retainers fixed to the control retainer and the input shaft in pockets provided in both the retainers. A sprag as an engaging element that engages with the opposing surface by relative rotation of the container in forward and reverse directions,
An elastic member that holds the sprag at a position that does not engage with the opposing surface is incorporated, and the control retainer and the output shaft are connected to the input shaft so that they can rotate together with the input shaft via a gap in the rotational direction. A holding member for elastically holding the input shaft at a neutral position in the rotational direction gap is provided, and the outer ring includes:
A transfer for a four-wheel drive vehicle including a connection portion with a drive shaft connected to a differential of front wheels.