JP2599305B2 - Power distribution control device for four-wheel drive vehicle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power distribution control device for a four-wheel drive vehicle equipped with a compound planetary gear type center differential device, and more particularly to a transfer axle type device with a manual transmission. And an assembly structure of a transmission output side, a front and rear wheel drive system, a center differential device, and a differential limiting device.

[Conventional technology]

2. Description of the Related Art Conventionally, as for a four-wheel drive vehicle with a center differential device based on a vertical transaxle type with a manual transmission, for example, there is a prior art of British Patent No. 1,114,756. Here, a bevel gear type center differential device is coaxially arranged in the transfer behind the output shaft of the transmission, and is transmitted from one side gear to the front wheels via a drive shaft inside the transmission output shaft and a pair of gears. The transmission is configured to be transmitted from the other side gear to the rear wheel. Then, equal torque is distributed to the front and rear wheels by the center differential device.

Further, for example, in the prior art of U.S. Pat. No. 3,748,928, it is disclosed that unequal torque is distributed to front and rear wheels using a simple planetary gear type center differential device, and a differential limiting device is provided between front and rear output elements.

[Problems to be solved by the invention]

By the way, in the former of the prior art, a bevel gear type equal torque distribution is used, and the running performance on rough roads is maximized, but slippage occurs easily on low μ roads and the like. If a differential limiting function is added to the center differential device to prevent this slip, the driving force will be improved, but the maneuverability will not be particularly improved. In some cases, the four wheels may slip at the same time, making steering difficult.

Further, in the latter case of the prior art, the steering stability is ensured even in the slip state because of the unequal torque distribution in which the rear wheel torque distribution is large. However, when combined with a transaxle type, the combination is a carrier input, a sun gear front wheel output, and a ring gear rear wheel output, and the input elements are arranged coaxially with the front wheel output element and outside, so that simple combination is not possible. . In addition, there is a problem in that there is no flexibility in setting the torque distribution, and the device becomes large.

Further, when the drive pinion of the front drive shaft directly meshes with the hypoid final gear as in the present invention, a large thrust load is generated. For this reason, the front drive shaft inside the transmission output shaft and the components connected to the front drive shaft must be securely supported so that a thrust load can be received in the front-rear direction. In this regard, the former of the prior art has two front drive shafts and two drive pinions.
Due to the split structure, the bearing is easy, but the front drive transmission system is complicated, and the latter requires the bearing to be configured before and after the hydraulic multiple clutch. For this reason, there is a problem that the whole structure becomes complicated, the assemblability, rigidity and the like are deteriorated, and the bearing structure is lengthened.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a vertical transaxle type transmission having a manual transmission, a transmission output shaft, a front drive shaft therein, a center differential device, and a differential. When the motion limiting devices are arranged coaxially, they are integrally fastened so that they can receive a thrust load, which shortens the drive system and improves the workability of assembly, etc., and has a compact structure. However, an object of the present invention is to provide a power distribution control device for a four-wheel drive vehicle that can increase the degree of freedom in torque distribution.

[Means for solving the problem]

In order to achieve the above object, a power distribution device for a four-wheel drive vehicle according to the present invention includes a front drive shaft disposed inside an output shaft of a manual transmission, which is directly connected to a front differential device. In a four-wheel drive vehicle in which a center differential device is arranged between a front drive shaft and a transfer shaft to a rear wheel, the front drive shaft is extended rearward, and the transmission output shaft, the center, and the center are arranged on the front drive shaft. An output element and a transfer shaft connected to the front drive shaft by a differential device are connected via a thrust bearing, and integrally fastened by a lock nut at a terminal end of the front drive shaft, and the front drive shaft, the transmission output shaft and the transfer On the shaft, the center differential The center differential device comprises a transmission output shaft, a sun gear formed on a transfer shaft, a pinion integrally formed and meshing with each sun gear, and a pinion. It is a compound planetary gear type comprising a carrier to be supported, and is characterized in that both sides of the carrier are bearing-supported and connected to a front drive shaft between two pinions and assembled.

[Action]

Based on the above configuration, a transmission output shaft, a transmission output shaft, and a front drive shaft directly connected to the front differential device.
A center differential device, a differential limiting device, a transfer shaft, and the like are attached and fastened with a lock nut to be integrally assembled. Then, torque is distributed to the front and rear wheels by a compound planetary gear type center differential device, and torque distribution control is performed by a differential limiting device according to slip or the like.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, a vertical transaxle type drive system to which the present invention is applied will be described. An extension case 3 is joined to a transmission case 1 via a transfer case 2. Then, the engine-side crankshaft 11 is connected to the clutch 13 via the flywheel 12, and the input shaft 16 from the clutch 13 is input to the manual transmission 30. The output shaft 19 of the manual transmission 30 is arranged parallel to the input shaft 16 and is connected to a center differential device 50 inside the transfer case 2. A front drive shaft 20 is inserted into the transmission output shaft 19, and a center differential device 50 is connected to the front differential device 21 via the front drive shaft 20. Transmission.

The front drive shaft 20 extends further toward the extension case 3 behind the center differential device 50, and is provided outside the front drive shaft 20 behind the center differential device 50 at the transfer shaft 22, a viscous cup for limiting the differential. A ring 60 is coaxially arranged, a transfer drive gear 24 is spline-coupled to the transfer shaft 22, and is positioned and supported on the extension case 3 by a ball bearing 42d. On the other hand, a rear drive shaft 23 is disposed at substantially the same height as the input shaft 16, and the rear end of the rear drive shaft 23 is attached to the bearing 2a of the transfer case 2 by a needle bearing.
The extension case 3 is fitted through the thrust bearing 41a and supported by the thrust bearing 41a.
Is supported by the ball bearing 42a of the bearing portion 3a. The driven gear 25 of the rear drive shaft 23 meshes with the transfer drive gear 24 so as to transmit power to the rear wheels.

The manual transmission 30 is of a constant mesh type, and has a first to fifth speed transmission gears between a parallel input shaft 16 and an output shaft 19.
31 to 35 and synchro mechanisms 36 to 38 are provided, and a selective meshing reverse gear mechanism 39 is further provided on the outer periphery of the synchro mechanism 36. And the sync mechanism 36 or 38
By selecting one of the transmission gears 31 to 35, the shift from the first gear to the fifth gear is performed, and the reverse gear mechanism 39 obtains the reverse gear.

In FIG. 2, a center differential device 50 is shown.
And the viscous coupling 60 will be described.

The center differential device 50 includes a transmission output shaft arranged coaxially with the front drive shaft 20 and outside thereof.
19, a transfer shaft 22 is provided. That is, a first sun gear 51 is formed on the input-side transmission output shaft 19, and a second sun gear 53 is formed on the output-side transfer shaft 22, and the first and second pinions 52 and 54 of the pinion member 56 are 1, mesh with the second sun gear 51,53. Then, a pinion member 56 is supported via a needle bearing 40b on a pinion shaft 57 of a carrier 55 connected to a similar front drive shaft 20 on the output side, thus forming a compound planetary gear system.

Here, the carrier 55 has a shape in which the left and right flanges 55a and 55b are integrated by an arm 55c.
The first and second pinions 52, 54 are driven by the pinion shaft 57 during 5b.
Is erected. A spline 20a is formed in the middle of the front drive shaft 20, and a connecting member 55d is spline-coupled to the spline 20a between the first and second pinions 52, 54.
The engaging portion 55e of the arm 55c of the connecting member 55d is spline-connected and connected to the front drive shaft 20 side. Further, one flange 55a is positioned and supported by a ball bearing 42b of a bearing 2b of the transfer case 2, and the other flange 55b is a ball bearing 4 of the transfer shaft 22.
It is installed rotatably supported by 2c.

Thus, the power of the transmission output shaft 19 is transferred to the first sun gear 51.
To the carrier 5 via the first and second pinions 52, 54.
Torque is transmitted to 5 and second sun gear 53 at a predetermined distribution ratio. When the torque is transmitted, the carrier 55 and the second pinion 52, 54 rotate and revolve to form the carrier 55 and the second pinion 52, 54.
This absorbs the difference in rotation speed between the sun gear 53 and the sun gear 53.

Here, the torque distribution of the center differential device 50 will be described in detail with reference to the schematic diagram of FIG.

The input torque of the first sun gear 51 is Ti, the meshing pitch radius is rs ₁ , the front torque of the carrier 55 is TF,
The engagement pitch radii of the first and second pinions 52, 54 are rp ₁ , r
Assuming that p ₂ , TR is the rear torque of the second sun gear 53 and rs ₂ is the meshing pitch radius, Ti = TF + TR (1) rs ₁ + rp ₁ = rs ₂ + rp ₂ (2) A first sun gear 51 and a first pinion 52
Tangential load P acting on the meshing point between the tangential load P ₁ acting on the carrier 55, the tangential load P ₂ acting on the meshing point between the second sun gear 53 and the second pin-on 54 Equal to the sum.

_{P = Ti / rs 1 P 1} = TF / (rs 1 + rp 1) P 2 = TRrs 2 Ti / rs 1 = {(TF / (rs 1 + rp 1)} + TR / rs 2 (3) (1), ( Substituting equation (2) into equation (3) and rearranging gives: TF = (1−rp ₁ · rs ₂ / rs ₁ ·· rp ₂ ) × Ti TR = (rp ₁ · rs ₂ / rs ₁ · rp ₂ ) × Ti, which indicates that the first and second sun gears 51 and 53 and the
1, by the meshing pitch radius with the second pinion 52, 54,
It can be seen that the reference torque distribution of the front torque TF and the rear torque TR can be set freely.

Here, rs ₁ = 23.5 mm, rp ₁ = 16.5 mm, rp ₂ = 18.8 mm, rs ₂
= 21.2mm, TF = 20/53 · Ti TR = 33/53 · Ti Accordingly, the front and rear wheel torque distribution is TF: TR ≒ 38: 62, and the reference torque distribution for rear wheel biasing can be set sufficiently.

Next, regarding the viscous coupling 60,
The cylindrical case 61 connects the connecting portion 61a to the flange 55b of the carrier 55.
The hub 62 is spline-coupled to the transfer shaft 22 integrally with the transfer shaft 22. Inside the case 61, the case-side outer plates 63 and the hub-side inner plates 64 are alternately arranged,
The case 61 and the hub 62 are sealed with an oil seal 65, and oil such as silicon is sealed inside.

In this way, the viscous coupling 60 is provided between the carrier 55 of one output shaft and the second sun gear 53 on the other output side so as to be bypassed. A torque is generated to bypass the torque from the high rotation side to the low rotation side.

Further, an assembly structure of the transmission output shaft 19, the front drive shaft 20, the center differential device 50, the transfer shaft 22, and the like arranged coaxially will be described.

First, a drive pinion 21a of a front differential device 21 is formed at the tip of the front drive shaft 20, and meshes with a hypoid final gear 21b. The transmission output shaft 19 is fitted to the front drive shaft 20 via needle bearings 40c and 40d at both ends, and the transfer shaft 22 is fitted and supported via needle bearings 40e and 40f at both ends.

Therefore, the front end of the transmission output shaft 19 is abutted against the front end step portion 20b of the front drive shaft 20 via the adjustment washer 43a, and the transmission output shaft 19 is driven by the driven gears 31a to 35a of the transmission gears 31 to 35, The hub 36a of the mechanism 36 and the double tapered roller bearing 44 of the bearing 1a of the transmission case 1 are mounted in contact with each other. The above-mentioned gears and the like are fastened to the transmission output shaft 19 by screwing the lock nut 45a of the transmission output shaft 19 to the terminal gear 35a via the washer 44a. Further, the tapered roller bearing 44 is fixed to the bearing portion 1a by a bolt 46, so that the transmission output shaft 19 and the front drive shaft 20 are positioned in the axial direction together with the gears and the like, and in this case, the bearing 44 and the bearing portion 1a The meshing state between the drive pinion 21a and the final gear 21b is adjusted with the shim 47 interposed therebetween.

Further, on the front drive shaft 20 and behind the transmission output shaft 19, the carrier 55 is provided via thrust bearings 41b and 41c.
The connecting member 55d and the transfer shaft 22 are sequentially connected, and the center differential device 50, the viscous coupling 60, and the transfer drive gear 24 are assembled.
Then, at the end of the front drive shaft 20, the transfer shaft 22
, A lock nut 45b is screwed via an adjustment washer 43b and a washer 44b, whereby the transmission output shaft 19, the connecting member 55d, and the transfer shaft 22 are pre-loaded on the front drive shaft 20 in a state where they can rotate with each other. It is applied and fastened integrally.

Next, the operation of the four-wheel drive vehicle configured as described above will be described.

First, the power of the engine 10 is input to the manual transmission 30 via the clutch 13 and the input shaft 16, and the transmission power shifted by the manual transmission 30 is transmitted from the transmission output shaft 19 to the first of the center differential device 50. Input to sun gear 51. Here, for example, TF: TR ≒ 38: 62 is set according to the specifications of each gear element of the center differential device 50, so that a torque of 38% of the shifting power is applied to the carrier 55 and a torque of 62%
Is distributed to the second sun gear 53 and output.

Then, the 38% torque output to the carrier 55 is transmitted to the front wheels via the front drive shaft 20 and the front differential device 21 as it is. Also, the second sun gear
The 62% torque output to 23 is transferred to transfer shaft 22, transfer drive gear 24, transfer driven gear 25,
The power is transmitted to the rear wheels after the rear drive shaft 23, and the vehicle is driven in a four-wheel drive mode with rear wheels biased. In this torque distribution, the steering tends to be understeer, so that the maneuverability can be ensured satisfactorily. Also, at the time of turning, the center differential device 50 rotates and revolves the first and second pinions 52, 54 in accordance with the rotational speed difference between the front and rear wheels, thereby completely absorbing the rotational speed difference.
It is possible to turn freely.

Next, when traveling on a slippery road surface, the rear wheels always slip first due to the torque distribution of the rear wheel bias. Then, the outer plate 63 integrated with the carrier 55 on the front wheel side, the case 61 and the transfer shaft 22 on the rear wheel side by the viscous coupling 60,
A large rotational speed difference occurs between the hub 62 and the integral inner plate 64 to generate a differential limiting torque, and the torque is bypassed from the high-speed transfer shaft 22 to the low-speed carrier 55 by the differential limiting torque. I do. Therefore, the torque distribution of the front and rear wheels is controlled closer to the front wheels to prevent slippage and improve running performance.

Also, at the time of the above-mentioned four-wheel drive, the drive pinion 21a of the front differential device 21 and the final gear 22b
A thrust load is generated at the meshing point of the front drive shaft 20 and acts on the front drive shaft 20 in the axial direction. Therefore, since the transmission output shaft 19, the connecting member 55d, and the transfer shaft 22 are coaxially connected to the front drive shaft 20 by being preloaded with a lock nut 45b or the like, the above-described thrust load is reduced by the transmission output shaft 19. It is reversed via the shaft 19 and the like and acts in the opposite direction of the front drive shaft 20 to be canceled.

Although the embodiments of the present invention have been described above, a hydraulic multi-plate clutch may be used instead of the viscous coupling. It is also possible to connect a rear drive shaft coaxially behind the transfer shaft.

〔The invention's effect〕

As described above, according to the present invention, in a vertical transaxle type four-wheel drive vehicle equipped with a manual transmission and having a center differential device and a differential limiting device assembled, a transmission output shaft, a front differential Since the center differential device and the differential limiting device are combined adjacently to a front drive shaft or the like that directly meshes with the device, it is possible to prevent the entire drive system from being lengthened, and to ensure the livability of the passenger compartment.

Furthermore, since the manual transmission is used as it is and only a transfer unit having a center differential device for torque distribution of rear wheel bias and a differential limiting device for torque distribution control is combined, it is advantageous in terms of production and cost. is there.

Furthermore, since the front drive shaft and the assembly of the center differential device and the differential limiter are integrated with the assembly on the transmission output shaft side by fastening with a lock nut at the end, assembly workability is improved. I do. Also,
The thrust load and the like of the drive pinion can be reduced.

In addition, the center differential device is a compound planetary gear type, which is input and output at the center part, so that it is compact, and since both sides of the carrier are supported by ball bearings, the positioning accuracy, durability and the like are improved.
The degree of freedom in setting the torque distribution is improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing an embodiment of a power distribution control device for a four-wheel drive vehicle of the present invention. FIG. 2 is an enlarged sectional view of a transfer unit including a center differential device. FIG. 3 is a schematic diagram illustrating a torque distribution state. 19 ... transmission output shaft, 20 ... front drive shaft, 21 ...
... Front differential device, 22 ... Transfer shaft, 23 ... Rear drive shaft, 30 ... Manual transmission, 41b,
41c …… Thrust bearing, 45b …… Lock nut, 50
…… Center differential device, 55… Carrier, 55d… Connecting member, 60… Viscous coupling

Claims (2)

(57) [Claims] A front drive shaft disposed inside an output shaft of a manual transmission is directly connected to a front differential device, and a center differential is provided between the transmission output shaft, the front drive shaft and a transfer shaft to a rear wheel. In a four-wheel drive vehicle in which the device is disposed, the front drive shaft extends rearward, and the transmission output shaft on the front drive shaft,
The output element connected to the front drive shaft and the transfer shaft are connected via a thrust bearing by a center differential device, and are integrally fastened by a lock nut at the end of the front drive shaft, and the front drive shaft, the transmission output shaft and The above-mentioned center differential device and differential limiting device are coaxially combined on a transfer shaft, and the center differential device is integrally formed with a transmission output shaft, a sun gear formed on a transfer shaft. It is a composite planetary gear system consisting of a pinion that meshes with each sun gear and a carrier that supports the pinion,
A power distribution control device for a four-wheel drive vehicle, characterized in that both sides of the carrier are supported by bearings and connected to a front drive shaft between two pinions and assembled. 2. The power distribution control device for a four-wheel drive vehicle according to claim 1, wherein the differential limiting device is installed between the carrier and the transfer shaft in a bypass manner.