JP3648871B2 - Power transmission device for four-wheel drive vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power transmission device for a four-wheel drive vehicle.
[0002]
[Prior art]
Among four-wheel drive vehicles, for example, there is a horizontally mounted engine type in which the output shaft of the engine is arranged so as to extend in the left-right direction of the vehicle body. This type of four-wheel drive vehicle is configured to add a transfer to the transmission, thereby transmitting the driving force of the engine to the front and rear wheels.
[0003]
In such a four-wheel drive vehicle, four wheels on the front, rear, left and right are driven at the same time or as needed. However, in the case of always driving, a center differential and an inter-wheel differential are generally provided. Inevitably, the number of components increases. However, it is desirable that the dimensions in the axial direction and the radial direction in the drive system (that is, transmission and transfer) be as small as possible to achieve compactness. Therefore, various devices have been made for that purpose.
[0004]
One example is a casing in which a transmission and a transfer are arranged side by side in an external casing having a predetermined shape, and a final ring gear (input gear) that meshes with a drive gear (output gear) of an output shaft in the transmission is provided. The member is formed of a cylindrical body having different diameters having a small diameter part and a large diameter part, and the one end side small diameter part of the casing member is rotatably supported with respect to the differential case via a needle bearing, while the other end of the casing member A final ring gear is provided on the outer periphery of the large-diameter side portion, and a center differential and an inter-wheel differential (front and rear) are arranged side by side in close proximity to shorten the axial and radial dimensions. A device with improved assemblability such as a differential device has been proposed (for example, a special Akira see Japanese Unexamined Patent Publication No. 63-68425).
[0005]
[Problems to be solved by the invention]
However, in the above-mentioned known example, as described above, the one end side small-diameter portion of the casing member is rotatably supported with respect to the differential case via the needle bearing so that it can be rotated about one axle. Therefore, a large force in the centripetal direction is applied to the final ring gear on the casing member large-diameter portion side when the gear is engaged with the transmission-side drive gear and the amplified drive torque is input. . If it does so, the phenomenon in which the casing member large diameter part side edge part without a support part will bend or fall will arise.
[0006]
When the above phenomenon occurs, the gear group (for example, planetary gear group) constituting the center differential and the inter-wheel differential disposed in the casing member will be adversely affected, for example, due to change in tooth contact or abnormal meshing. There is a risk of problems such as seizure, wear, and abnormal noise.
[0007]
The present invention has been made in view of such points, and without sacrificing compactness, the support rigidity of the casing member large-diameter portion end side having the final ring gear is increased, and the bending in the radial direction and the lateral direction are increased. It is an object of the present invention to provide a power transmission device for a four-wheel drive vehicle that prevents as much as possible the adverse effects on the differential portion by preventing the body from falling down.
[0008]
[Means for Solving the Problems]
In the configuration of the invention of claim 1 of the present application, as means for solving the above-described problems, a transmission that is connected in series with a horizontally mounted engine and whose output shaft extends in the vehicle width direction, and the output shaft of the transmission An output gear provided in the transmission, an axle connected in parallel to the output shaft of the transmission, connected to the left and right wheels, a center differential and an inter-wheel differential arranged in parallel on the axle, and one end side having a small diameter. One end side small diameter cylindrical body part is formed in the cylindrical body part, while the other end side is formed in a large diameter cylindrical body part, and the other end side large diameter cylindrical body part covers the center differential and the inter-wheel differential. And a final ring gear that is provided on the outer periphery of the large-diameter cylindrical portion on the other end side of the casing member and meshes with the output gear on the transmission side. With the door, the power transmission device for a four-wheel drive vehicle comprising accommodates these portions in the outer casing, and the wheel between differential is arranged on the opposite side with respect to the center differential on the axle, and the axle Is provided with a transfer gear for transmitting power to another axle, and on the side of the final ring gear, the other end side large-diameter cylindrical body portion is supported from the radially outer side to the outer casing. A side support plate is provided , and the outer side support plate is disposed between the final ring gear and the transfer gear in a state orthogonal to a drive shaft disposed inside the casing member .
[0009]
Therefore, according to this means, even if the transmission side output gear is greatly decelerated from the transmission side output gear and the amplified driving force is transmitted, even if the falling force acts on the large-diameter cylindrical body side of the casing member. Since the large-diameter cylindrical body side of the casing member is reliably supported in both the axial direction and the radial direction by the outer side support plate provided on the side of the final ring gear, the final ring gear side It will be possible to reliably prevent the occurrence of falling.
[0010]
Further, in the configuration of the invention of claim 2 of the present application, in the configuration of the invention of claim 1, the outer casing is divided into two in the axial direction and is constituted by a pair of split casings, and the outer support plate is The outer casing is constituted by a separate member and is interposed between the two divided casings and fastened and fixed .
[0011]
【The invention's effect】
As a result, according to the power transmission device for a four-wheel drive vehicle of the present invention, the following beneficial effects can be obtained.
[0012]
By configuring as in the first aspect of the invention, it is possible to increase the supporting rigidity (supporting force) of the open end of the final ring gear, and to surely prevent the casing member itself from being bent or laterally tilted. Can do.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0014]
1 shows the overall configuration of the four-wheel drive vehicle according to the embodiment, FIG. 2 shows the configuration of the power transmission device of the four-wheel drive vehicle, and FIG. 3 shows the configuration of the main part of the power transmission device. Each is shown.
[0015]
(Overall configuration of four-wheel drive vehicle)
First, in FIG. 1, reference numeral 1 denotes a vehicle body, 2 is an in-line four-cylinder engine mounted horizontally in a front portion of the vehicle body 1 with a crankshaft 2 a extending in the left-right direction of the vehicle body, and 3 is a left side of the engine 2. It is also a transmission mounted horizontally. The transmission 3 is disposed in an outer casing 4 (configured integrally with a casing of a transfer 24 described later), is disposed in series with the crankshaft 2 a of the engine 2, and the clutch device 5. And an output shaft 7 arranged in parallel with the input shaft 6 and switching the gear transmission path between the input / output shafts 6 and 7 to transmit power. The gear ratio of the hour is switched.
[0016]
On the vehicle body rear side of the transmission 3, front axle shafts 8, 8 divided as left and right acting as drive shafts and a transfer output shaft 9 positioned on the vehicle body rear side are respectively connected to the input / output of the transmission 3. The left and right front axle shafts 8, 8 are connected to the left and right front wheels 12, 12 via joints 10, 10,... And left and right drive shafts 11, 11, respectively. .
[0017]
A right end portion of the transfer output shaft 9 is connected to a front end of a propeller shaft 14 extending in the longitudinal direction of the vehicle body via a bevel gear mechanism 13, and a rear end of the propeller shaft 14 is divided into a left and right rear axle shaft 15, 15 is connected to the rear differential 16. The rear differential 16 includes a differential case 18 connected to the propeller shaft 14 via a bevel gear mechanism 17, a pair of pinions 19, 19 supported by the differential case 18, and meshed with the pinions 19, 19 and left and right rear axles. It consists of a pair of side gears 20 and 20 fixed to the inner ends of the shafts 15 and 15, and the outer ends of the left and right rear axle shafts 15 and 15 are connected via joints 21, 21, and left and right drive shafts 22 and 22. It is connected to the left and right rear wheels 23, 23.
[0018]
On the left and right front axle shafts 8 and 8, a center differential 25 and a front differential 26 constituting the transfer 24 are arranged in parallel. The center differential 25 distributes power to the front and rear wheels 12 and 23, and the front differential 26 functions as a wheel-to-wheel differential that distributes power to the front wheels 12 and 12.
[0019]
Next, the specific structure of the transfer 24 will be described in detail with reference to the enlarged sectional view of FIG.
[0020]
A differential case 27 of the front differential 26 is rotatably fitted on the left and right axle shafts 8 and 8. The differential case 27 is integrally formed with cylindrical sleeve portions 27b, 27b on the left and right sides of a hollow spherical main body 27a, and is coupled to the left and right axle shafts 8, 8 respectively in the main body 27a. A pair of side gears 28, 28 and a pair of pinions 29, 29 meshed with the side gears 28 and rotatably supported by the main body 27a by pinion shafts 29a disposed at right angles to the axle shafts 8, 8. Is fitted.
[0021]
The center differential 25 is rotatably fitted on the left sleeve portion 26b of the differential case 27, and the sun gear 30 and the ring gear 31 are connected to each other via two pinions 33 and 34 supported by a pinion carrier 32. It consists of a double pinion type planetary gear mechanism that is in mesh engagement.
[0022]
On the other hand, 35 is a ring gear casing (casing member). One end side of the ring gear casing 35 is formed in a small-diameter cylindrical portion, and the small-diameter cylindrical portion is configured as a pivotal support portion 35a. Is formed in a large-diameter cylindrical body portion that is gradually expanded in a funnel shape, and the large-diameter cylindrical body portion extends in the left end direction so as to cover the entire center differential 25 and the front differential 26, and the other end is opened. A projecting edge bearing fitting portion 35b is provided on the opening end side. A ring gear 31 is formed on the inner peripheral surface of the left end portion (open side end portion) corresponding to the sun gear 30 of the substantially funnel-shaped ring gear casing 35, while the ring gear casing 35 corresponds to the sun gear 30. A final ring gear 37 that meshes with the output gear 36 of the output shaft 7 in the transmission 3 is formed on the outer peripheral surface near the opening end. Further, a cylindrical pivotal support portion 35a composed of a cylindrical portion having a small diameter on the right side in the ring gear casing 35 is rotatably fitted to a right sleeve portion 27b of the differential case 27 in the front differential 26 so that the axle shaft 8 is attached. It is supported so as to be rotatable in a centered state. Further, the pinion carrier 32 is rotatably coupled to a differential case 27 of the front differential 26.
[0023]
That is, as described above, the center differential 25 and the front differential 26 are disposed in the large-diameter cylindrical body portion of the ring gear casing 35 formed on the outer peripheral side of the final ring gear 37 that meshes with the output gear 36 of the output shaft 7 in the transmission 3. Are arranged in close proximity to each other on the same axis so that the axial and radial dimensions of the transfer 24 can be made as short as possible.
[0024]
A transfer gear 38 that is integrated with the sun gear 30 and transmits power to the rear wheels 23 and 23 is disposed on the front axle shaft 8 on the left side of the center differential 25 (that is, opposite to the front differential 26). ing. The sun gear 30 and the transfer gear 38 are provided so as to rotate integrally with the sleeve portion 27b of the differential case 27 in the front differential 26, and the transfer gear 38 is integrated with the left end portion of the transfer output shaft 9. It is meshed with a transmission gear 39 that is rotatably provided.
[0025]
Further, silicon oil or the like is sealed in a sealed space formed by the inner cylinder 40a and the outer cylinder 40b on the front axle shaft 8 on the left side of the transfer gear 38 (that is, opposite to the center differential 25). A viscous coupling 40 is arranged. The inner cylinder 40a of the viscous coupling 40 is spline-coupled to the sleeve portion 27b of the differential case 27 of the front differential 26 while the outer cylinder 40b is spline-coupled to the transfer gear 38 so as to be integrally rotatable. Yes. On the differential case 27 between the viscous coupling 40 and the transfer gear 38, a thrust bearing 41 for receiving a thrust force in the left direction of the transfer gear 38 (that is, the direction toward the viscous coupling 40) is disposed. The relative coupling between the differential case 27 of the front differential 26 and the transfer gear 38 (in other words, relative rotation of the front and rear wheels 12, 24) is restricted by the viscous coupling 40.
[0026]
In addition, on the right sleeve portion 27b of the differential case 27 in the front differential 26, a pivot portion 35a of the ring gear casing 35 extending to the right front axle shaft 8 and a differential case of the front differential 26 by a sleeve 42 that slides. 27, a mechanical diff lock mechanism 43 that stops the operation of the center differential 25 by connecting the diff lock mechanism 43 to the lock position is provided. The four-wheel drive state in which the front and rear wheels are directly connected can be achieved. It is supposed to be obtained.
[0027]
The transfer output shaft 9 is divided into a solid left shaft 9a and a hollow cylindrical right shaft 9b in the axial direction, and the divided shafts 9a and 9b are intermittently connected to the divided portion. A 2/4 wheel drive switching mechanism 44 is provided for switching and transmitting the driving force of the engine 2 only to the front wheels 12, 12 or to the front and rear wheels 12, 12, 23, 23. The 2/4 wheel drive switching mechanism 44 can also prevent the wheel on the side being lifted from rotating by the action of the viscous coupling 40 when the wheel is pulled. In the figure, reference numerals 45 and 46 denote bearings for pivotally supporting the front axle shafts 8 and 8 on the transfer casing 4.
[0028]
In the above configuration, the output of the engine 2 is transmitted to the ring gear 31 constituting the center differential 25 through the ring gear casing 35 having the final ring gear 37 that meshes with the output gear 36 of the output shaft 7 of the transmission 3. It is distributed to the 12 side and the rear wheel 23 side.
[0029]
The output to the front wheel 12 side is transmitted from the pinion carrier 32 constituting the center differential 25 to the front wheels 12 and 12 through the front differential 26, the front axle shafts 8 and 8, and the left and right drive shafts 11 and 11.
[0030]
On the other hand, for the output to the rear wheel 23 side, the sun gear 30 of the center differential 25 to the transfer gear 38, the transmission gear 39, the transfer output shaft 9, the bevel gear mechanism 17, the propeller shaft 14, the rear differential 16, the rear axle shafts 15, 15 and It is transmitted to the rear wheels 23 and 23 via the left and right drive shafts 22 and 22.
[0031]
Further, a difference in rotation occurs between the front and rear wheels 12 and 23, and the differential case 27 of the front differential 26 connected to the front wheels 12 and 12 and the transfer gear 38 connected to the rear wheels 23 and 23 are relative to each other. Even if it tries to rotate, it is restricted by the viscous coupling 40 interposed between the differential case 27 and the transfer gear 38, and an appropriate driving force is transmitted to the front and rear wheels 12 and 23.
[0032]
By the way, in the present embodiment, the transfer casing 4 is formed by a pair of split casings 4a and 4b that are split into two in the axial direction at a predetermined position (for example, a position between the sun gear 30, the final ring gear 37, and the transfer gear 38). A ring gear casing support plate (outside support plate ) 46 having a vertical wall structure as will be described later is interposed between the divided casings 4a and 4b. It is fastened and fixed integrally. In other words, the transfer casing 4 has a vertical wall portion with high support rigidity in the middle. The ring gear support plate 46 is disposed in a state orthogonal to the drive shaft (that is, the front axle shafts 8 and 8) disposed in the ring gear casing 35.
[0033]
3 and 4, the ring gear support plate 46 is formed of a plate-like member having a predetermined thickness having bolt holes 46 b, 46 b... On the outer peripheral portion, and the insertion hole 46 a through which the transmission 3 is inserted. In addition, an insertion hole 46c for inserting the transfer 24 and an insertion hole 46d for inserting the transfer output shaft 9 are provided. The ring gear support plate 46 is formed between the output gear 36 of the transmission output shaft 7 and the final ring gear 37 on the outer periphery of the ring gear casing 35 on the outer side of the opening end portion of the large-diameter side cylindrical body portion of the ring gear casing 35. A ring gear casing that is located outside the meshing portion (left side in the drawing) and rotatably supports the open end of the large-diameter side cylindrical portion of the ring gear casing 35 from the radially outer side and the side from the transfer casing 4. The ring gear casing support plate 46 and the bearing fitting portion 35b formed as a projecting edge toward the inner edge side of the open end of the large-diameter side cylindrical body portion of the ring gear casing 35 as described above. Between the bearing cover 48 formed on the inner peripheral portion of the transfer insertion hole 46c of the shaft, Ball bearing 52 as a rotation support means for regulating the movement of direction is interposed.
[0034]
A cylindrical pivot portion 35a of the ring gear casing 35 is a roller bearing 53 which is a rotation support means for restricting the movement in the axial direction with respect to the inner peripheral surface of one divided casing 4a constituting the transfer casing 4. It is supported so that it can rotate freely. Here, the roller bearing 53 is used because it is supported by line contact, and the support strength in the direction perpendicular to the axis can be increased as compared with the ball bearing, and the support rigidity of the ring gear casing 35 itself can be further increased.
[0035]
When the structure of the support portions at both ends of the ring gear casing 35 is configured as described above, the opening end side of the large-diameter cylindrical body portion of the ring gear casing 35 (that is, the outer end portion on the side of the final ring gear 37) is supported rigidly. The ring gear casing support plate 46 having a high vertical wall structure is firmly supported by the transfer casing 4 (4a, 4b) from the side (axial direction) and radially outward via the ball bearing 52. Thus, the support rigidity against a large input torque accompanying the deceleration to the ring gear casing 35 is greatly increased. Therefore, when power is transmitted from the transmission-side output shaft 7 to the ring gear casing 35 side, the opening end of the large-diameter cylindrical body portion of the ring gear casing 35 is deflected or laterally caused by the force in the centripetal direction acting on the ring gear casing 35. So that the gear group constituting the center differential 25 and the front differential 26 disposed in the large-diameter cylindrical body portion of the ring gear casing 35 can always maintain a normal meshing state. Become. That is, it is possible to reliably prevent changes in tooth contact, seizure, abnormal wear, abnormal noise, and the like that may occur in the gear group constituting the center differential 25 and the front differential 26.
[0036]
Moreover, the ring gear casing 35 is supported at the one end side thereof by the pivotal support 35a in a line contact state via the roller bearing 53 with high support rigidity in the axial direction and the radial direction so as to be rotatable with respect to the transfer casing 4. Therefore, the ring gear casing 35 is stably supported together on both ends in the axial direction together with the support by the ring gear support plate 46, and the support rigidity including the thrust direction and the radial direction is more certain. Will be enhanced.
[0037]
In the case of the present embodiment, after assembling the front differential 26, the center differential 25 and the viscous coupling 40 in advance with respect to one of the divided casings 4a in the transfer casing 4, the ball is moved from the left direction. By assembling the bearing 52 and the ring gear casing support plate 46 and then bolting up the other divided casing 4b with respect to the divided casing 4a, the transfer can be assembled relatively easily (that is, smooth from one side in the axial direction). Assembly is possible). Therefore, workability and work efficiency at the time of assembly are greatly improved. In addition, since the ring gear casing support plate 46 is interposed between the split casings 4a and 4b in the transfer casing 4 and is integrally fastened, the ring gear casing support plate 46 reinforces the transfer casing 4 itself. It also functions as a member, and the rigidity of the entire transfer casing 4 is further enhanced.
[0038]
Further, since the ring gear casing support plate 46 is disposed perpendicular to the drive shaft (that is, the front axle shaft 8) disposed inside the ring gear casing 35, the ring gear support plate 46 itself generates a drive reaction force. As a result, the support rigidity of the drive system such as the differential is further increased.
[0039]
In the above embodiment, the ring gear casing support plate 46 that supports the outer side of the final ring gear 37 forming portion of the ring gear casing 35 is configured by a member different from the transfer casing 4. You may make it comprise integrally.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a configuration of an entire transmission system of a power transmission device of a four-wheel drive vehicle according to an embodiment of the present invention.
FIG. 2 is an enlarged sectional view showing a configuration of a main part of the power transmission device of the four-wheel drive vehicle (FIGS. 3A-A).
FIG. 3 is a side view of a ring gear casing support plate in the configuration of the main part.
[Explanation of symbols]
2 is an engine, 2a is a crankshaft, 3 is a transmission, 5 is a crank device, 7 is an output shaft, 8 is a front axle shaft, 9 is a transfer output shaft, 11 is a drive shaft, 13 is a bevel gear mechanism, 18 is a differential case, 19 Is a pinion, 20 is a side gear, 24 is a transfer, 25 is a center differential, 26 is a front differential, 27 is a differential case, 30 is a sun gear, 31 is a ring gear, 35 is a ring gear casing, 36 is an output gear, 37 is a final ring gear, and 38 is a transfer. Reference numeral 39 denotes a transmission gear, 40 denotes a viscous coupling, 46 denotes a ring gear casing support plate, 52 denotes a ball bearing, and 53 denotes a roller bearing.

Claims (2)

A transmission that is connected in series to a horizontally mounted engine and whose output shaft extends in the vehicle width direction, an output gear provided on the output shaft of the transmission, and a parallel arrangement with respect to the output shaft of the transmission , An axle connected to the left and right wheels, a center differential and an inter-wheel differential arranged side by side on the axle, and one end side is formed in a small diameter cylindrical body portion, while the other end side is formed in a large diameter cylindrical body portion A casing member formed by fitting one end side small diameter cylindrical body portion to the axle in a state where the other end side large diameter cylindrical body portion covers the center differential and the wheel differential, and the other end of the casing member A four-wheel drive vehicle comprising a final ring gear that is provided on the outer periphery of the large-diameter cylindrical body portion and meshes with the output gear on the transmission side. In a force transmission device,
Provided on the opposite side of the wheel differential to the center differential on the axle, providing a transfer gear for transmitting power to an axle different from the axle,
Provided on the side of the final ring gear is an outer side support plate that supports the large-diameter cylindrical portion of the other end of the casing member from the radially outer side to the outer casing ,
The power of a four-wheel drive vehicle, wherein the outer support plate is disposed between the final ring gear and the transfer gear in a state orthogonal to a drive shaft disposed inside the casing member. Transmission device. The outer casing is divided into two in the axial direction and is constituted by a pair of divided casings.
The four-wheel drive vehicle according to claim 1, wherein the outer side support plate is constituted by a member different from the outer casing, and is interposed between the two divided casings and fastened and fixed. Power transmission device.

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