JP2000108704A - Combination planetary gear device and center differential device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combination planetary ear device capable of easily and inexpensively changing the torque distribution in a center differential device, without increasing the kinds of parts. SOLUTION: A combination planetary gear device is provided with a first sun gear 51, a second sun gear 53 as well as a first pinion 52 meshed with the first sun gear 51 and a second pinion 54 integrally formed with the first pinion 52 to be meshed with the second sun gear 53 disposed in their periphery. In the gear device, the first sun gear 51 and the first pinion 52 are formed with profile shifted gears. When the combination planetary gear device is used for a center differential device of a 4-wheel-drive car, by changing the number of the teeth and the addendum modification coefficient of the first sun gear 51, the reference torque distribution of both front and rear wheels can easily be changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compound planetary gear device, and more particularly to a technology effective when applied to a center differential device of a four-wheel drive vehicle.

[0002]

2. Description of the Related Art In general, in a four-wheel drive vehicle, a center differential device is provided at a rear stage of a transmission in order to provide a differential function of front and rear wheels. Is often used. Further, in this composite planetary gear device, the reference torque distribution to the front and rear wheels can be arbitrarily set by variously changing its specifications, and thus, the engine torque is widely distributed to the front and rear wheels. ing.

Here, in a four-wheel drive vehicle, the running characteristics of the vehicle can be changed by the reference torque distribution ratio.
In other words, if the rear wheel bias is set by distributing a large amount of torque to the rear wheels, the vehicle will have an oversteer running characteristic close to that of a rear wheel drive vehicle, and the turning and maneuverability will be good. Also,
If the torque is equally distributed to the front and rear wheels, the running characteristics will be maximized. Further, when a large amount of torque is distributed to the front wheels, the vehicle tends to be understeered, so that it is possible to improve running performance and stability. For this reason, in a four-wheel drive vehicle, the reference torque distribution for the front and rear wheels is set in accordance with the use, the type of vehicle, and the like, and these are performed by changing the gear ratio in the above-described compound planetary gear device.

FIG. 5 is an explanatory diagram showing an outline of a gear configuration of the composite planetary gear device. In FIG. 5, reference numeral 71 denotes a first sun gear, which is provided integrally with an intermediate shaft (input shaft) 72 to which rotation from the engine is transmitted. Reference numeral 73 denotes a second sun gear, which is provided integrally with a rear drive shaft (output shaft) 74 on the rear wheel side. Further, the first sun gear 71 meshes with the first pinion 75, and the second sun gear 73 meshes with the second pinion 76. The first and second pinions 75, 76 are integrally attached to the carrier 77. In addition, rotation is transmitted to the front wheels via a reduction gear (not shown) fixed to the carrier 77.

In the configuration of FIG. 5, for example, when the torque distribution ratio is 50:50, the first sun gear 71 is
The teeth and the second sun gear 73 have 18 teeth, and the first and second pinions 75 and 76 have 21 teeth. Thus, the input torque T input from the intermediate shaft 72
i is the front torque T output from the carrier 77
F and the rear torque TR output from the rear drive shaft 74 are equally divided. On the other hand, when the torque distribution ratio is 45.5: 54.5, the first sun gear 71
Have 33 teeth, the second sun gear 73 has 18 teeth, and the first and second pinions 75 and 76 have 21 teeth. As described above, in the composite planetary gear device, the torque distribution of the front and rear wheels can be freely set by changing the gear configuration.
It is widely used as torque distribution means for wheel drive vehicles.

[0006]

However, in the conventional compound planetary gear device, when changing the torque distribution ratio, the gear specifications are changed on both the drive side and the driven side. Therefore, either the intermediate shaft or the rear drive shaft and the pinion 2
The type of parts needed to be changed.

For example, in the case of FIG. 5, although the rear drive shaft 74 on which the second sun gear 73 is formed can be shared, the intermediate shaft 72 on which the first sun gear 71 is formed must be newly designed and manufactured. The first and second pinions 75 and 76 have the same number of teeth even when the torque distribution ratio is changed.
Since the third sun gear 3 is shared, it is necessary to adjust the distance between the shafts on the first sun gear 71 side. For this reason, it is necessary to change the module on the first sun gear 71 side, which also needs to be newly designed and manufactured.

That is, in the composite planetary gear device,
Although it is easy to change the torque distribution ratio, a new part is generated each time, and the type of parts increases, which is disadvantageous in terms of parts management and cost.

An object of the present invention is to provide a composite planetary gear device that can easily and inexpensively change the torque distribution ratio in a center differential device without increasing the types of parts.

[0010]

SUMMARY OF THE INVENTION A compound planetary gear device according to the present invention includes a first sun gear and a second sun gear disposed coaxially with the first sun gear, and is provided on outer peripheral sides of the first and second sun gears. , A first pinion meshing with the first sun gear, and a second pinion integrally formed with the first pinion and meshing with the second sun gear, wherein the first planetary gear device comprises: One or both of the sun gears are formed by a shift gear, and the shift coefficient of the shift gear is changed to change the number of teeth.

[0011] Thus, by changing the number of teeth of the sun gear formed by changing the transposition coefficient, the gear ratio in the composite planetary gear device is changed. Therefore, the gear ratio can be changed without designing and manufacturing a new pinion, and an increase in the number of parts can be suppressed.

Further, another composite planetary gear device of the present invention includes a first sun gear and a second sun gear disposed coaxially with the first sun gear, and a first sun gear and an outer peripheral side of the first and second sun gears. A first pinion that meshes with one sun gear;
A second sun gear formed integrally with the pinion and engaged with the second sun gear;
A compound planetary gear device having a pinion disposed therein, wherein one or both of a first pinion and a second pinion are formed by a shift gear, and the number of teeth is changed by changing a shift coefficient of the shift gear. It is characterized by:

Thus, by changing the number of teeth of the pinion formed by changing the dislocation coefficient, the gear ratio in the composite planetary gear device is changed. Therefore, the gear ratio can be changed without designing and manufacturing a new sun gear, and an increase in the number of types of parts can be suppressed.

Further, another center differential device of the present invention is a center differential device of a four-wheel drive vehicle using the compound planetary gear device, wherein a shift coefficient and a number of teeth of the shift gear are changed. The feature is that the reference torque distribution of the front and rear wheels of the four-wheel drive vehicle can be changed.

Thus, the torque distribution ratio can be changed only by replacing the first sun gear, for example.
An increase in the types of parts is suppressed, which is advantageous in terms of parts management, production management, and product costs.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a skeleton diagram showing a configuration of a drive system of a four-wheel drive vehicle using a compound planetary gear device according to an embodiment of the present invention.

Here, first, a transmission case 3 is joined to the rear portions of the torque converter case 1 and the differential case 2. A transfer case 4 and an extension case 6 are joined to the rear part. An oil pan 5 is attached to a lower part of the transmission case 3.

Reference numeral 10 denotes an engine. A crankshaft 11 of the engine 10 is connected to a torque converter 13 provided inside the torque converter case 1 and having a lock-up clutch 12. An input shaft 14 extends from the torque converter 13. The input shaft 14 is connected to the automatic transmission 3 inside the transmission case 3.
It has grown to zero. From the automatic transmission 30, the transmission output shaft 1
5 is output coaxially with the input shaft 14, and the transmission output shaft 15 is coaxially connected to a center differential device 50 inside the transfer case 4.

Inside the transmission case 3, a front drive shaft 16 is arranged parallel to the input and output shafts 14 and 15. This front drive shaft 1
The rear end of 6 is connected to a center differential device 50 via a pair of reduction gears 17 and 18. The front end is connected to a front differential device 19 inside the differential case 2, through which engine rotation is transmitted to the front wheels. On the other hand, at the rear of the center differential device 50,
A hydraulic multiple disc clutch device 60 is provided. And
The output of the rear drive shaft 20 is the propeller shaft 2
1, connected to the rear differential device 22 and the like, through which engine rotation is transmitted to the rear wheels.

The automatic transmission 30 has a structure in which four forward gears and one reverse gear are obtained by two sets of front planetary gears 31 and rear planetary gears 32. Here, the input shaft 14 is connected to a sun gear 32 a of the rear planetary gear 32. Further, a ring gear 31 b of the front planetary gear 31 and a carrier 32 c of the rear planetary gear 32 are connected to the transmission output shaft 15. A first one-way clutch 34 and a forward clutch 35 are provided in series between a coupling element 33 integral with the carrier 31c of the front planetary gear 31 and the ring gear 32b. A second one-way clutch 36 and a low reverse brake 37 are provided in parallel between the connecting element 33 and a case serving as a fixing member. Further, an overrunning clutch 38 is provided between the connection element 33 and the ring gear 32b, bypassing the same.

The connecting element 39 integral with the sun gear 31a is provided with a band brake 40. A high clutch 43 is provided between the connecting element 41 integrated with the input shaft 14 and the connecting element 42 integrated with the carrier 31c. Further, a reverse clutch 44 is provided between the connecting elements 39 and 41.

On the other hand, an oil pump 45 is installed in front of the automatic transmission 30 (to the left in FIG. 1), and is driven by a drive shaft 46 on the pump impeller side of the torque converter 13. The oil pan 5 has a control valve body 4
The control oil is supplied to and discharged from the clutches and brakes.

Next, a center differential device 50 and a hydraulic multiple disc clutch device 60 are provided behind the automatic transmission 30 (to the right in FIG. 1). In this case, a rear drive shaft 20 is coaxially disposed behind the transmission output shaft 15 via first and second intermediate shafts 23 and 24. Further, a reduction gear 17 on the front wheel side is rotatably fitted to the transmission output shaft 15. And
A center differential device 50 is coaxially arranged between the transmission output shaft 15, the reduction gear 17, and the first and second intermediate shafts 23, 24.

This center differential device 50
Is composed of a compound planetary gear device provided with planetary gears, and has a configuration similar to that shown in FIG. FIG.
FIG. 2 is an exploded perspective view of the center differential device 50. As shown in FIG. 2, the center differential device 50 has a first sun gear 51 formed on the transmission output shaft 15 and a second sun gear 53 formed on the second intermediate shaft 24, and around them. The first and second pinions 52 and 54 supported by the carrier 55 are arranged.

The carrier 55 includes left and right flanges 55a,
55b is integrated with an arm 55c. In this case, a pinion shaft 56 is bridged between the two flanges 55a and 55b, and first and second pinions 52 and 54 formed integrally in the axial direction are rotatably provided via bearings. It is installed. The first pinion 52 is provided on the first sun gear 51 and the second sun gear 5
The second pinion 54 meshes with the third pinion 3 to output the torque-distributed power to the second intermediate shaft 24.

On the other hand, the first intermediate shaft 23 is loosely fitted inside the second intermediate shaft 24. Also, the first intermediate shaft 23
A connecting member 57 is provided in the gap between the first and second sun gears 51 and 53 at the front end of the connecting member 57. The connecting member 57 is integrally and spline-coupled to the arm 55c of the carrier 55, and performs an operation such as a differential restriction. Further, one flange 55a of the carrier 55
, A reduction gear 17 is coupled to output the power of the carrier 55. In this case, the carrier 55
Is supported by supporting a reduction gear 17 integrally provided therewith on a side wall of the transmission case 3 with a bearing (not shown). On the rear side, the outer periphery of the boss 55d is supported by a bearing (not shown) with respect to the transfer case 4,
The inner circumference of the bearing 26 is
Supported by being supported by. Thus, the carrier 55 is rotatably installed with both ends supported.

Flanges 55e are provided at three locations on the circumference of the rear flange 55b of the carrier 55. This collar 5
The three sets of pinion shafts 56 and the first and second pinions 52 and 54 are mounted at equal intervals by 5e and the front flange 55a. Also, arms 55c are arranged at three places on the circumference between them. The arm 55c has a U-shaped middle and is formed to have a small diameter, and a spline groove 55g is provided on the inner periphery of the small diameter portion 55f. The connecting member 57 coupled to the end of the first intermediate shaft 23 is formed in a substantially triangular shape, and three locations on the circumference are formed in an L-shaped cross section, and a spline groove 57a is provided. These spline grooves 55g and 57a are
The diameter is set slightly smaller than the inner diameter of the boss 55d of the flange 55b. Then, the connecting member 57 of the first intermediate shaft 23 is inserted from the boss 55d into the carrier 55 with the two spline grooves aligned. Thus, the spline grooves 55g and 57a are fitted, and the carrier 55 and the connecting member 57 are connected.

With such a configuration, the center differential device 50 transmits the power input to the first sun gear 51 to the first and second sun gears 51 and 53 and the first and second sun gears 51 and 53.
The torque is transmitted to the carrier 55 and the second sun gear 53 at a torque distribution ratio according to gear specifications with the pinions 52 and 54. Also, due to the planetary rotation of the first and second pinions 52, 54,
Carrier 55 caused by a difference in turning radius when turning the vehicle
It also has a differential function of absorbing a rotational speed difference between the second sun gear 53 and the second sun gear 53.

Further, a hydraulic multiple disc clutch device 60 is provided behind the center differential device 50. In the hydraulic multiple disc clutch device 60, first, a hydraulic multiple disc clutch 61 as a friction engagement element for transmitting torque is interposed between the second intermediate shaft 24 and the rear drive shaft 20. Also, the first intermediate shaft 23 and the rear drive shaft 20
A hydraulic multi-plate clutch 62 as a frictional engagement element for limiting the differential and moving the torque is interposed between the two. Further, the second intermediate shaft 24 is provided with a fifth speed brake 63 as a frictional engagement element for preventing the differential function of the center differential device 50 and rotating the carrier 55 at an increased speed.

The hydraulic multi-plate clutches 61 and 62 and the fifth-speed brake 63 are superimposed three times in the radial direction around the first intermediate shaft 23 and the like immediately after the center differential device 50 so as to be coaxial. Are located. In this case, both the hydraulic multi-plate clutches 61 and 62 are connected to the rear drive shaft 20, and the hydraulic multi-plate clutch 61 and the fifth speed brake 63 are both connected to the second intermediate shaft 24. Accordingly, the hydraulic multiple disc clutch 61 is disposed at the middle, the fifth speed brake 63 is disposed outside the clutch, and the hydraulic multiple disc clutch 62 is disposed inside the fifth speed brake 63.

The hydraulic multi-plate clutches 61 and 62 and the fifth speed brake 63 are provided with a control valve body 47.
Thus, the hydraulic pressure is controlled together with the shift control of the automatic transmission 30 and the like.
That is, when the automatic transmission 30 shifts to four forward speeds and one reverse speed, the fifth speed brake 63 is released and the hydraulic multiple disc clutch 61 is engaged. By variably controlling the engagement of the hydraulic multi-plate clutch 62, the hydraulic multi-plate clutch 62 applies a differential limiting torque Tc according to rear wheel slip or the like.
Occurs. When the vehicle speed rises above the set value at the fourth speed, the fifth speed brake 63 is engaged and the hydraulic multiple disc clutch 61 is released. As a result, the second sun gear 53 is fixed, the carrier 55 rotates at an increased speed, and the automatic transmission 30
The fifth speed can be achieved in combination with the predetermined gear (second speed).

Next, the center differential device 5
The torque distribution function at 0 will be described with reference to FIG. FIG. 3 is an explanatory diagram showing a torque distribution state in the center differential device 50. In this case, the input torque of the first sun gear 51 is Ti, the mesh pitch radius thereof is rs1, and the front torque of the carrier 55 is T.
F. The meshing pitch radii of the first and second pinions 52 and 54 are rp1 and rp2. Furthermore, the second
The rear side torque of the sun gear 53 is TR, and the meshing pitch radius is rs2.

At this time, the following relationship is established between the torque and the meshing pitch radius.

[0034]

(Equation 1)

The first sun gear 51 and the first pinion 5
The tangential load P acting on the meshing point with the carrier 2 is
5 and the tangential load P acting on the meshing point between the second sun gear 53 and the second pinion 54.
2 (P = P1 + P2). Then, in this case, P = Ti / rs1, P1 = TF / (rs1 + rp1)
1) Since P2 = TR / rs2, the following equation is obtained.

[0036]

(Equation 2)

Therefore, the following relation is obtained by substituting the equations (1) and (2) into the equation (3) and rearranging them.

[0038]

(Equation 3)

Accordingly, the reference torque distribution ratio of the front side torque TF and the rear side torque TR is determined by appropriately setting the engagement pitch radius between the first and second sun gears 51 and 53 and the first and second pinions 52 and 54. It can be seen that it can be set freely by changing. In this case, the meshing pitch radii rs1, rp1, rp2, rs2 can be replaced by the number of teeth Zs1, Zp1, Zp2, Zs2 of each gear. Therefore, for example, Zp1 = Zp2 = 21, Zs
If 1 = 33 and Zs2 = 18, TF: TR = 45.
5: 54.5, and the reference torque distribution ratio for rear wheel bias is set.

On the other hand, the torque distribution ratio is "50:50".
Is required, Zp1 = Zp2
= 21, Zs1 = 36, and Zs2 = 18. At this time, the number of teeth differs only in the number of teeth of the first sun gear 51, and there is no change in the number of teeth of other gears. However, even in such a case with the conventional compound planetary gear device, the second
Except for sharing the sun gear 53, the reference torque distribution ratio is set using a separately designed and manufactured one. This is because if the number of teeth of the first sun gear 51 is changed, if the first and second pinions 52 and 54 are used as they are, the inter-axis distances will not match.

Therefore, in the composite planetary gear device according to the present invention, the first sun gear 51 and the first pinion 52 are formed by shifting gears so that other parts can be shared even in such a case, and the shaft is changed by changing the number of teeth. Changes in the inter-distance are absorbed by appropriately adjusting the amount of dislocation (dislocation coefficient). For example, if the dislocation coefficient is Xn, the first
The pinion 52 is set to “Zp1 = 21; Xn = −0.15”, and the first sun gear 51 is a shift gear of “Xn = 0.15766” when Zs1 = 33, while Zs
In the case of 1 = 36, it is a shift gear of “Xn = −1.2557”.

FIG. 4 is a specification table of these gears. It can be seen from the table of FIG. 4 that the inter-axis distance of the meshing pitch circle between the first sun gear 51 and the first pinion 52 is 40.5 mm regardless of which first sun gear 51 is used.
This indicates that any of the first sun gears 51 can mesh with the first pinion 52 without changing the distance between the shafts. That is, in the composite planetary gear device, the gear ratio can be changed only by replacing the first sun gear 51, and accordingly, the torque distribution ratio is also changed.

For this reason, conventionally, it was necessary to change at least two types of components to change the torque distribution ratio, but this can be dealt with by changing one type of component as described above. Therefore, it is possible to reduce the number of types of parts, which is advantageous not only in parts management and production management, but also in product costs.

The present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the scope of the present invention.

For example, in the above-described embodiment, an example is shown in which the first sun gear 51 and the first pinion 52 are formed by shift gears. However, the second sun gear 53 and the second pinion 54 are formed by shift gears. You may do it. Further, it is also possible to form all of them by using a displaced gear so that the gear ratio can be changed in a wider range. Furthermore, only the first sun gear 51 (or the second sun gear 53) can be used as a shift gear, and the first pinion 52 (or the second pinion 54) can be used as a standard gear. Note that the number of teeth and the dislocation coefficient of each gear described above are merely examples, and it is needless to say that the scope of the present invention is not limited thereto.
Further, with respect to the displaced gear, it is possible to increase the tooth width in order to maintain the strength.

[0046]

According to the present invention, since the first sun gear in the compound planetary gear device is formed by a shift gear, the gear ratio of the compound planetary gear device can be changed by exchanging one type of component. Therefore, by using the composite planetary gear device for the center differential device of a four-wheel drive vehicle, it is possible to change the torque distribution ratio only by replacing the first sun gear, for example. For this reason, it is possible to reduce the number of types of parts, which is advantageous not only in parts management and production management, but also in reducing product costs.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing a configuration of a drive system of a four-wheel drive vehicle using a compound planetary gear device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a center differential device.

FIG. 3 is an explanatory diagram showing a torque distribution state in a center differential device.

FIG. 4 is a table of specifications of each gear in the composite planetary gear device according to the present invention.

FIG. 5 is an explanatory diagram showing an outline of a gear configuration of the composite planetary gear device.

[Explanation of symbols]

 15 Transmission output shaft 23 First intermediate shaft 24 Second intermediate shaft 50 Center differential device 51 First sun gear 52 First pinion 53 Second sun gear 54 Second pinion 55 Carrier

Claims (3)

[Claims] 1. A first pinion, comprising: a first sun gear; and a second sun gear disposed coaxially with the first sun gear, and a first pinion meshed with the first sun gear on outer peripheral sides of the first and second sun gears. And a second pinion formed integrally with the first pinion and meshing with the second sun gear, wherein one or both of the first sun gear and the second sun gear are provided. A compound planetary gear device formed of a dislocation gear, wherein the number of teeth is changed by changing the dislocation coefficient of the dislocation gear. 2. A first pinion, comprising: a first sun gear; and a second sun gear disposed coaxially with the first sun gear, and a first pinion meshing with the first sun gear on outer peripheral sides of the first and second sun gears. And a second pinion integrally formed with the first pinion and meshing with the second sun gear, wherein one or both of the first pinion and the second pinion are provided. A compound planetary gear device formed of a dislocation gear, wherein the number of teeth is changed by changing the dislocation coefficient of the dislocation gear. 3. A center differential device of a four-wheel drive vehicle using the compound planetary gear device according to claim 1 or 2, wherein the four-wheel drive is performed by changing a shift coefficient and a number of teeth of the shift gear. A center differential device wherein reference torque distribution of front and rear wheels of a vehicle can be changed.