JPH10272943A - Transfer structure of four-wheel drive vehicle - Google Patents

Abstract

(57) Abstract: In a transfer structure of a four-wheel drive vehicle, a change in tooth contact of a bevel gear is reduced, the workability of tooth contact inspection is improved, and a seal member mounted on a transfer shaft is provided. Reduce deformation during use. The transfer includes a transfer shaft (15) rotatably supported by three bearings (J1 to J3) and having an input gear (14) at one end, a transfer output shaft (18), and hypoid gear sets (16, 17) provided between the two shafts. In a transfer structure of a four-wheel drive vehicle in which a subassembly body As configured by assembling the unit Tf in the transfer case 20 in advance is assembled to the transmission Tm side,
A hollow member 35 is non-rotatably disposed on the outer peripheral side of the transfer shaft, and both ends of the hollow member are rotatably supported by bearings J2 and J3. It is characterized by being attached so as to be close to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transfer structure for a four-wheel drive vehicle.

[0002]

2. Description of the Related Art Conventionally, in a four-wheel drive vehicle of a type in which a transmission is arranged in series with a horizontally mounted engine, a first axle (for example, a so-called FF) which is arranged in parallel with an output shaft of the transmission and receives driving force. In the case of a vehicle of the type, the driving force is not directly taken out from the front axle (so-called one-shaft type), but a transfer shaft as a kind of intermediate shaft for power transmission is arranged in parallel with the first axle. And a so-called two-shaft type in which power is transmitted to a propeller shaft via the transfer shaft. In the case of this two-shaft type, by setting the vertical position of the transfer shaft to be lower than the first axle by a fixed value or more, the position of the propeller shaft can be suitably lowered. It is possible to avoid such a problem that the airbag protrudes high toward the cabin and adversely affects the livability in the cabin.

The input gear of the transfer shaft is usually
For example, it meshes with a ring gear fixed to a case body (differential case) of a differential device disposed between left and right wheels on the front wheel axle, and receives power transmission from an output gear of the transmission in proximity to the output ring gear. A final ring gear is provided. Therefore, in the case of a so-called double-sided support in which the transfer shaft is supported at both ends and an input gear is provided in the middle thereof, generally, the transfer shaft crosses the rotation surface of the final ring gear and the final ring gear If they have a diameter larger than a certain value, they interfere with each other.
For this reason, the diameter of the final ring gear is limited to a certain value or less, and when the distance between the output shaft of the transmission and the front wheel axle is determined, the reduction ratio between the output gear of the transmission and the final ring gear can be freely set. The degree will be greatly limited.

To solve such a problem, see, for example,
JP 08760 (hereinafter referred to as prior art 1)
In this, a transfer shaft arranged in the vehicle width direction, a transfer output shaft extending in a direction perpendicular to the shaft, and a bevel gear set provided between these two shafts are provided, and the transfer shaft is provided in a case body. On the other hand, there is disclosed a transfer structure in which an input gear that is rotatably supported at three points near and at both ends and at the center via a bearing member and receives a driving force from an engine is provided at one end outside the supporting position of the bearing member. Have been. Thus, by providing the input gear at one end outside the position supported by the bearing member of the transfer shaft,
When the support structure of the transfer shaft is a so-called cantilever support with respect to the load input point, the positions of the two are set so that the transfer shaft does not cross the rotation surface of the final ring gear as in the above-mentioned prior art 1. It is extremely easy to do.

[0005] By setting the two positions in this manner, the diameter of the final ring gear is no longer limited by the existence of the transfer shaft, and the distance between the output shaft of the transmission and the front wheel axle is determined. In this case, the degree of freedom in setting the reduction ratio between the output gear of the transmission and the final ring gear can be greatly increased.
In the transfer structure according to the prior art 1, the input gear provided on the transfer shaft is arranged at a position distant from the bevel gear set, and is inserted from the side. Since the input gear is cantilevered, the radial support of the input gear must be strengthened. Therefore, the transfer shaft is supported by a total of three bearings.

In the above-described two-shaft type four-wheel drive vehicle, the transfer shaft is rotated in a direction perpendicular to the transfer shaft (that is, the propeller shaft) in order to convert the power to a 90-degree direction and transmit the power to the propeller shaft. The power transmission between these two shafts is usually performed using a bevel gear such as a bevel gear or a hypoid gear which is a kind of a torsion bevel gear. When assembling such a bevel gear type gear set, generally, a transfer case supporting a transfer output shaft is assembled from a propeller axis direction with the transfer shaft supported on the case body side of the transmission. However, if the meshing state of the bevel gear set does not accurately define the position in three dimensions, problems such as noise and wear will occur. Therefore, individual manufacturing errors for each part are absorbed by using shims. I am trying to do it. At this time, in the case of assembling from the propeller axial direction, it was necessary to accurately control and adjust the tightening torque and shim on the joint surface of the case.

To simplify this work, as in the prior art 1, the transfer shaft, the transfer output shaft, and the bevel gear set are previously assembled to the transfer case, and the meshing state of the bevel gear set is adjusted first. It is known that a transfer case is assembled from the side of the case body of the transmission in the adjusted state. In this case, the transfer unit including the transfer shaft and the transfer output shaft, the bearings supporting these shafts, and the power transmission gears and other components provided on each shaft is pre-assembled into a transfer case to form a sub-assembly body. And the sub-assembly is connected to the case of the transmission.

A transfer unit for transmitting power between a transfer shaft and a transfer output shaft, which includes a bevel gear such as a hypoid gear and a meshing portion thereof, and a transmission side on which the transfer unit is assembled are used. The requirements for lubricating oils are generally different. That is, in the case of the transmission oil used in the transmission, in addition to the function as the lubricating oil for the sliding portion and the meshing portion of the internal mechanism, for example, a hydraulic oil that generates a hydraulic pressure for driving an operating component such as a valve spool. As the function is required, a material having a relatively low viscosity is selected.On the other hand, in the case of a transfer unit, in general, for lubricating bevel gears such as the hypoid gear, which is required to have a high load resistance. , High viscosity oil is used. Therefore, when the transfer unit is assembled on the transmission side, for example, Japanese Patent Application Laid-Open No. 3-22772
As shown in Japanese Patent Publication No. 7 (hereinafter referred to as Conventional Technique 2), the space of the transfer unit including the meshing portion of the bevel gear and the space closer to the transmission than that are sealed in a liquid-tight manner. Need to be partitioned.

[0009]

By the way, when the shaft member is 3
When a point is supported and a load input point is set at one end outside of these support points to form a cantilever support structure, the radial displacement of the shaft member is compared at the center support point among the three support points. Only need to be small. However, in the transfer structure according to the prior art 1, the bevel gear that transmits the driving force to the transfer output shaft is provided on the transfer shaft.
It is provided near the end side farthest from the input gear that is the load input point, and when the transmission load is applied to the input gear with the power transmission to the transfer shaft, the radial displacement of the bevel gear is sufficiently reduced. It is difficult to regulate. For this reason,
There has been a problem that the tooth contact changes with use, which is disadvantageous in terms of noise problems and gear life.

Further, in the transfer structure according to the prior art 1, the transfer case has two cylindrical portions extending at right angles to each other for accommodating the transfer shaft and the transfer output shaft. After assembling, a cover member for covering the end of each cylindrical portion is provided. To check the meshing state (tooth contact) of the bevel gear set, after assembling the transfer shaft and the transfer output shaft, respectively, Since there is no choice but to visually inspect the tooth contact from the opening covered by the cover member, the workability of the tooth contact inspection is poor, and the accuracy of the tooth contact inspection may be deteriorated.

On the other hand, in the case of the seal structure disclosed in the above-mentioned prior art 2, the transfer shaft is supported only at both ends by its rotation, and both support portions (bearings) having a large radial displacement.
A seal member is disposed at a substantially middle portion of the seal member. Therefore, when the transfer shaft rotates while receiving the transmission load, there is a problem that the deformation of the seal member is increased and the deterioration is apt to occur at an early stage.

The present invention has been made in view of the above problems, and in a transfer structure of a four-wheel drive vehicle, a change in tooth contact of a bevel gear is reduced, workability of tooth contact inspection is improved, and An object of the present invention is to reduce deformation of a seal member mounted on a transfer shaft during use.

[0013]

For this reason, the invention according to claim 1 of the present application (hereinafter referred to as a first invention) has a single transfer shaft disposed in the vehicle width direction and a single transfer shaft. And a bevel gear set provided between these two shafts, and the transfer shaft is rotatably supported via bearing members at three points near the ends and at the center with respect to the case body. In a transfer structure of a four-wheel drive vehicle, an input gear for receiving a driving force from an engine is provided at one end outside the supporting position of the bearing member.
A bevel gear for transmitting a driving force to the transfer output shaft is arranged close to a central bearing member among the three.

Further, the invention according to claim 2 of the present application (hereinafter referred to as “the invention”)
A second aspect of the invention includes a transfer shaft provided with an input gear for receiving a driving force transmitted from a transmission-side unit, a transfer output shaft extending in a direction perpendicular to the shaft, and a transfer shaft provided between these two shafts. In the transfer structure of a four-wheel drive vehicle in which a sub-assembly body is configured by previously assembling a transfer unit having a bevel gear set and a transfer case into a transfer case, and then assembling the sub-assembly body to the transmission-side unit, A hollow member of a predetermined length is provided on the outer peripheral side of the transfer shaft so as to be non-rotatable with respect to the transfer shaft, and both ends of the hollow member or the vicinity thereof are rotatable with respect to the transfer case via a bearing member. A bevel gear that supports and transfers driving force to the transfer output shaft is installed in the middle of the hollow member. It is characterized by the fact that

Further, the invention according to claim 3 of the present application (hereinafter referred to as “the invention”)
According to a third aspect of the present invention, in the second aspect, the bearing member is a tapered roller bearing.

Further, the invention according to claim 4 of the present application (hereinafter, referred to as a fourth invention) is characterized in that, in the second or third invention, a tooth contact of the bevel gear set is provided outside the bearing member. And a shim for adjusting is provided.

Further, the invention according to claim 5 of the present application (hereinafter referred to as “the invention”)
A fifth aspect of the present invention is a transmission case in which the transmission case is rotatably supported at three points near and at both ends of the transfer case via a bearing member, and a transmission-side unit is provided at one end outside the supporting position of the bearing member. A transfer shaft provided with an input gear receiving a driving force transmitted from the shaft, a transfer output shaft extending in a direction perpendicular to the shaft, and a bevel gear set provided between these two shafts. In a transfer structure of a four-wheel drive vehicle in which the sub-assembly is assembled to the transfer case in advance after assembling the sub-assembly with the transfer case, a hollow having a predetermined length is formed on the outer peripheral side of the transfer shaft. The member is arranged so as to be unrotatable with respect to the transfer shaft, and both ends of the hollow member or the vicinity thereof serve as bearing members. The transfer case is rotatably supported by the transfer case, and a bevel gear for transmitting a driving force to the transfer output shaft is provided at an intermediate portion of the hollow member so as to approach the center bearing member of the three. It is characterized in that it is attached in the manner described above.

Further, the invention according to claim 6 of the present application (hereinafter referred to as “the invention”)
A sixth aspect of the present invention includes a single transfer shaft arranged in the vehicle width direction, a transfer output shaft extending in a direction perpendicular to the shaft, and a bevel gear set provided between these two shafts. The transfer shaft is rotatably supported via a bearing member at three points near and at both ends of the transfer case via a bearing member, and is transmitted from the transmission-side unit to one end outside the supporting position of the bearing member. In a transfer structure of a four-wheel drive vehicle provided with an input gear receiving a driving force, two bearings are arranged between a bevel gear for transmitting a driving force to the transfer output shaft and the input gear, and between these bearings. In addition, a seal member that seals the input gear side space and the bevel gear side space communicating with the transmission side in a liquid-tight manner is disposed.

[0019]

According to the first aspect of the present invention,
By providing an input gear at one end outside the support position of the transfer shaft bearing member, the transfer shaft support structure is so-called cantilever support with respect to the load input point. , So that the transfer shaft does not cross the rotating surface of the final ring gear,
It is extremely easy to set the positions of both gears, the diameter of the final ring gear is no longer limited by the presence of the transfer shaft, and even if the distance between the output shaft of the transmission and the axle of the front wheel is set, the speed can be changed. The degree of freedom in setting the reduction ratio between the output gear of the machine and the final ring gear can be greatly increased. In addition, in this case, the bevel gear for transmitting the driving force of the engine to the transfer output shaft is arranged close to the central bearing member of the three bearing members, so that the radial displacement of the bevel gear can be reduced. Can be restricted, and a change in tooth contact of the bevel gear can be reduced. That is, while maintaining the effects of the cantilever support structure, noise of the bevel gear can be reduced and the life of the gear can be improved.

Further, according to the second aspect of the present invention, after the transfer unit is assembled in the transfer case in advance to form the sub-assembly body, the sub-assembly body is assembled to the transmission-side unit. The workability of assembling the unit can be improved. Moreover, in this case, a hollow member having a predetermined length is arranged on the outer peripheral side of the transfer shaft so as to be unrotatable with respect to the transfer shaft, and both ends of the hollow member or the vicinity thereof are connected to the transfer shaft via bearing members. A bevel gear that is rotatably supported with respect to the case and transmits the driving force to the transfer output shaft is mounted in the middle of the hollow member, so the bevel gear set tooth contact inspection can be performed without assembling the transfer shaft. It can be carried out. Therefore, the tooth contact inspection itself can be easily performed, and a readjustment operation can be easily performed when the tooth contact inspection fails.

Further, according to the third aspect of the present invention, basically the same effects as in the second aspect can be obtained. In addition, since the bearing member supporting both ends of the hollow member or its vicinity is a tapered roller bearing having high axial rigidity, the axial position of the bevel gear attached to the hollow member can be more accurately determined. Can be specified.

Still further, according to the fourth aspect of the present invention, basically the same effects as those of the second or third aspect can be obtained. In addition, since the shim for adjusting the tooth contact of the bevel gear set is disposed outside the bearing member, the axial position of the bevel gear can be more accurately defined.

According to the fifth aspect of the present invention, by providing an input gear at one end outside the position where the transfer shaft is supported by the bearing member, the transfer shaft support structure can be so-called one-sided with respect to the load input point. Since it was held and supported,
Compared to the case of the double-sided support structure, it is extremely easy to set the positions of the transfer ring so that the transfer shaft does not cross the rotating surface of the final ring gear, and the diameter of the final ring gear is limited by the existence of the transfer shaft. Therefore, even when the distance between the output shaft of the transmission and the front axle is determined, the degree of freedom in setting the reduction ratio between the output gear of the transmission and the final ring gear can be greatly increased. And in this case,
Since the bevel gear that transmits the driving force to the transfer output shaft is arranged close to the central bearing member of the three bearing members, the radial displacement of the bevel gear can be effectively restricted, The contact change of the bevel gear can be reduced. That is, while maintaining the effects of the cantilever support structure, noise of the bevel gear can be reduced and the life of the gear can be improved. Further, in this case, the transfer unit is previously assembled to the transfer case to form a sub-assembly body, and then the sub-assembly body is assembled to the transmission-side unit. Therefore, the workability of assembling the transfer unit is improved. In addition, a hollow member having a predetermined length is provided on the outer peripheral side of the transfer shaft so as to be unrotatable with respect to the transfer shaft, and both ends of the hollow member or the vicinity thereof are connected to the transfer shaft via bearing members. A bevel gear that is rotatably supported with respect to the case and transmits the driving force to the transfer output shaft is mounted in the middle of the hollow member, so the bevel gear set tooth contact inspection can be performed without assembling the transfer shaft. It can be carried out. Therefore, the tooth contact inspection itself can be easily performed, and a readjustment operation can be easily performed when the tooth contact inspection fails.

Further, according to the sixth aspect of the present invention, with respect to the transfer shaft whose rotation is supported by three bearing members, between the bevel gear for transmitting driving force to the transfer output shaft and the input gear, A bearing member is disposed between the two bearings, where the radial displacement of the transfer shaft is strongly restricted, and a seal member for liquid-tightly sealing the input gear side space and the bevel gear side space communicating with the transmission side is disposed. Therefore, the deformation of the seal member when the transfer shaft rotates while receiving the transmission load can be effectively suppressed, and the life of the seal member can be further improved.

[0025]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a skeleton diagram schematically illustrating a configuration of a power transmission device for a four-wheel drive vehicle according to the present embodiment. As shown in this figure, the four-wheel drive vehicle is, for example, a so-called FF type in which front wheels (not shown) can be constantly driven by an engine En disposed in a front portion of the vehicle, and is of a horizontal type. The engine En,
The output shaft 1 is arranged in the engine room with the output shaft 1 facing the vehicle width direction. On the output side of this engine En,
For example, an automatic transmission Tm is arranged in series with the engine output shaft 1, and the engine output shaft 1 is connected to a torque converter 3 housed in a case 2 of the transmission Tm.
It is connected to.

The transmission case 2 includes a torque converter housing 2A housing a torque converter 3, and a transmission housing 2B housing a transmission mechanism following the torque converter housing 2A. The torque converter housing 2A is adjacent to the engine En and is formed to have a larger diameter than other parts of the transmission case 2 (the transmission housing 2B and the like) because the torque converter 3 accommodates a large volume of the torque converter 3. And the transmission Tm is the engine En
Are arranged in series in the engine E in plan view.
n overhangs the rear side of the vehicle body.

An output gear 5 of a transmission mechanism is integrally fixed to the output shaft 4 of the transmission Tm. The output gear 5 constitutes a final reduction unit of the transmission Tm (in other words, the front wheels). A relatively large-diameter first ring gear (final ring gear) 6 (which serves as an input gear for the drive mechanism) meshes. The first ring gear 6 is more preferably fixed to the outer peripheral portion of the front differential 7. In other words, a differential device 7 between the left and right front wheels is disposed on the inner peripheral side of the large-diameter first ring gear 6 by effectively utilizing the inner space thereof, and the difference in which the volume is relatively large is provided. As for the arrangement of the moving devices 7, an efficient layout is realized.

Then, a pair of left and right first axles 8 (front wheel axles) for driving the front wheels via the front differential 7.
Extend in the vehicle width direction (that is, in parallel with the transmission output shaft 4). Each front wheel axle 8 is rotatably supported by bearings indicated by reference numerals △ and に お い て in the figure. Also, at the shaft end of each of these front wheel axles 8,
Front wheel drive shafts 9 for driving the front wheels are connected via universal joints 11, respectively. Thus, a so-called FF drive system capable of constantly driving the front wheels is configured, and the transmission T
m from the output shaft 4 is transmitted to the front wheel axle 8 via the output gear 5, the first ring gear 6, and the differential device 7 sequentially, and further transmitted to the front wheel drive shaft 9 via the universal joint 11. It is transmitted to.

Next, a power transmission system for variably controlling the distribution of the driving torque of the rear wheels will be described. A transfer shaft 15 rotatably supported behind the front wheel axle 8 by a predetermined distance is arranged in parallel with the front wheel axle 8. As can be clearly understood from FIG. 2, the transfer shaft 15 is set so that its vertical position is lower than the front wheel axle 8 by a predetermined amount, and accordingly, the driving force is directly transmitted from the front wheel axle. The vertical position of the propeller shaft 21 can be made lower than that of a single-shaft type that takes out the propeller shaft. In the present embodiment, a straight line L connecting the axis of the front wheel axle 8 and the axis of the transfer shaft 15 is shown.
The three shafts 4, 8, 15 are arranged such that the inclination angle β with respect to the horizon of the transmission 2 is larger than the inclination angle α with respect to the horizon of the straight line L1 connecting the axis of the transmission output shaft 4 and the axis of the front wheel axle 8.
Is set.

The transfer shaft 15 has 1
The power is transmitted from the front wheel axle 8 via a pair of gears 13 and 14. That is, the casing 10 of the front differential 7 arranged on the front wheel axle 8
More preferably, a second ring gear 13 is provided integrally with the front / diff case 10 on the outer peripheral portion of the (front / diff case), while the second ring gear 13 is provided on the left end of the transfer shaft 15 in FIG. An input gear 14 is provided which meshes with the input gear. That is, the second ring gear 13 constitutes an output gear for the transfer shaft 15 side.

A bevel gear type output gear 16 composed of, for example, a bevel gear or a hypoid type ring gear (in this embodiment, more preferably a hypoid ring gear) is located on the center side of the input shaft 14 of the transfer shaft 15. Fixed. The output gear 16 meshes with a pinion gear 17 of a bevel gear type provided at the front end of a transfer output shaft 18 extending in a direction perpendicular to the transfer shaft 15, and the driving force from the transfer shaft 15 is Transfer output shaft 18 converted by 90 degrees
Is transmitted to The output gear 16 is a transfer shaft 15
For example, the pinion gear 17 is more preferably spline-coupled to the transfer output shaft 1.
8 are integrally formed.

The transfer output shaft 18 is connected to a clutch 31 as a power variable transmission unit for variably transmitting the power of the transfer output shaft 18 to the rear wheel axle 23, and is connected to one of the working members. 31
The front end side of the propeller shaft 21 is connected to the other working member. The clutch 31 is operated by, for example, hydraulic pressure or electromagnetic suction. In the present embodiment, it is more preferable to control the operation of the clutch 31 according to, for example, the vehicle speed, the selection of a four-wheel drive, the degree of accelerator opening, and the like. Thereby, in addition to the front wheels, the rear wheels can be actively controlled.

As is well known, in a hypoid type gear set (a combination of the hypoid ring gear 16 and the hypoid pinion gear 17), the rotation center axes of the ring gear 16 and the pinion gear 17 are offset. Therefore, the vertical position of the rotating shaft (transfer output shaft 18) of the hypoid pinion gear 17 can be lowered by this offset amount, whereby the vertical position of the central axis of the propeller shaft 21 can be reduced to a predetermined size corresponding to the offset amount. Only the transfer axis 15 can be set lower than the central axis. That is, the propeller shaft 21
The height (therefore, the height of the floor tunnel that covers the upper side of the floor tunnel toward the passenger compartment) can be further reduced.

The transfer shaft 15 and the transfer output shaft 18, bearings for supporting these shafts 15, 18, respectively, and a power transmission gear 1 provided on each shaft.
A transfer unit Tf is formed of 4, 16, 17 and the like.
A clutch case 30 containing the clutch 31 is fastened and fixed to the rear end of the transfer case 0. The front end side of the transfer case 20 is fastened and fixed to a part of the transmission case 2 (specifically, a rear part of the torque converter housing 2A). The details of the structure of the transfer case 20 and the configuration and layout of the transfer unit Tf will be described later.

A driving force is transmitted from the propeller shaft 21 to a pair of left and right second axles 23 (rear wheel axles) through a rear differential device 22, and the driving force is transmitted through the universal joints 24. The left and right rear wheel drive shafts 25 respectively connected to the rear wheel axle 23 are rotationally driven.
That is, a gear shaft 27s of a rear pinion gear 27 made of, for example, a bevel gear or a hypoid gear (more preferably, a hypoid gear) is connected to the rear end side of the propeller shaft 21. Reference numeral 27 orthogonally meshes with a rear ring gear 26 fixed to the outer peripheral portion of the rear differential device 22. As a result, the driving force from the propeller shaft 21 becomes 90
The angle is converted and transmitted to the left and right rear axles 23.

Next, the structure of the transfer case 20 and the configuration / layout of the transfer unit Tf, assembling method, and the like will be described mainly with reference to FIGS. In the present embodiment, the front end side of the transfer case 20 is connected to the rear part of the torque converter housing 2A as described above, but as shown in FIG. The front differential 7 is incorporated and housed therein, and is partially open in the direction along the axis of the propeller shaft 21 (that is, rearward).
The first ring gear 6 and the second ring gear 13 project rearward. The first and second ring gears 6 and 13 are formed integrally, and are fastened and fixed to the case body of the front differential 7 by a plurality of bolt members Bt1.

On the other hand, the transfer case 20 is composed of a base portion 41 into which the transfer shaft 15 is inserted and stored, and a cylindrical portion 42 into which the transfer output shaft 18 extending in a direction perpendicular to the transfer shaft 15 is inserted and stored. An opening 2 is provided on the front side (upper side in FIG. 5).
0h is formed, and the opening 20h is covered with the lid member 50. The cover member 50 is provided with a plurality of bolt members Bt4.
To the transfer case 20. The configuration of the lid member 50 will be described later.

In this embodiment, the transfer shaft 1
Reference numeral 5 denotes three bearings J1 and J for the transfer case 20.
2 and J3 are rotatably supported via the bearings J1 and J3.
An input gear 14 for receiving a driving force is integrally provided on one end side (leftward in FIGS. 5 and 6) from the position supported by J2 and J3, and a driving force is applied to the transfer output shaft 18 in the middle thereof. Is mounted. The output gear 16 is arranged near the center bearing J2 of the three bearings J1, J2, J3.

That is, the base portion 41 of the transfer case 20 is provided with an annular shaft support portion 41a for mounting the cylindrical roller bearing J1 at the end (left side in FIGS. 5 and 6) on which the torque converter housing 2A is mounted. At the same time, semicircular support portions 41b and 41c for assembling the tapered roller bearings J2 and J3 are provided in order toward the inside of the case 20 (the right side in FIGS. 5 and 6). These two tapered roller bearings J2,
J3 is set on the shaft supporting portions 41b and 41c, and then fitted with a cap member 43 having a semicircular inner peripheral portion, and tightening the bolt member Bt5, whereby the shaft supporting portion 41 is set.
b, 41c. The rotation of the transfer output shaft 18 is supported by two tapered roller bearings J4 and J5.

In this embodiment, the output gear 1
6 and the bearings J2, J3 are actually fixed to a hollow member 35 described below. That is, in the present embodiment, a hollow member 35 having a predetermined length is arranged on the outer peripheral side of the transfer shaft 15. The hollow member 35 cannot rotate with respect to the transfer shaft 15 by, for example, spline fitting. The inner races of the tapered roller bearings J2 and J3 are press-fitted into both ends of the hollow member 35, and the hollow member 35 is mounted on the two tapered roller bearings J.
2, and is rotatably supported by the transfer case 20 via J3. The hypoid type output gear 16 for transmitting the driving force to the transfer output shaft is assembled in the middle of the hollow member 35, and the tapered roller bearings J2 and J3 are located on both sides thereof. In addition, the output gear 16 is arrange | positioned close to the center bearing J2 as mentioned above.

Further, shims Cm2 to Cm4 for adjusting the tooth contact of the hypoid gear sets 16, 17 are arranged outside the tapered roller bearings J2, J3, respectively. Tapered roller bearing J at the shaft end of the transfer shaft 15
The shim Cm4 arranged outside the inner ring of No. 3 is formed by a nut member 44 fastened to the shaft end of the transfer shaft 15.
It is pressed and fixed to the inner ring side of the tapered roller bearing J3. The shaft end of the transfer shaft 15 to which the nut member 44 is fastened is covered by a cover member 45. An adjustment shim Cm1 is interposed between the back surface of the hypoid gear 17 (pinion gear) formed integrally with the transfer output shaft 18 and the end surface of the inner ring of the tapered roller bearing J4.

In the present embodiment, the lubricating oil used differs between the transfer unit Tf including the hypoid gear sets 16 and 17 and the meshing portion thereof and the transmission Tm on which the transfer unit Tf is assembled. I have. That is, the transmission oil used for the transmission Tm is not only a function as a lubricating oil for the sliding portion and the meshing portion of the internal mechanism, but also a hydraulic oil for generating a hydraulic pressure for driving an operating component such as a valve spool. Therefore, a material having a relatively low viscosity is selected. On the other hand, regarding the lubricating oil used for the transfer unit Tf,
The hypoid gears 16 and 1 for which high load resistance is required
For lubrication of 7, a high viscosity oil is used.

When the transfer unit Tf is assembled on the transmission Tm side, the internal space of the transfer unit Tf including the meshing portion of the hypoid gear sets 16 and 17 and the space on the transmission Tm side are defined. In order to achieve a liquid-tight seal, a seal member S1 is mounted between the inner peripheral portion of the transfer case 20 and the outer peripheral portion of the transfer shaft 15. In this embodiment, two bearings J1 and J2 are located between the input gear 14 of the transfer shaft 15 and the hypoid type output gear 16, and the seal member S1 is located between these bearings J1 and J2. Are located. A drain port 34 closed by a plug 33 is provided on the side of the transfer case 20 so that it can be used for oil drain when replacing the lubricating oil in the case 20. Is

In the present embodiment, as described above,
An opening 20h is formed on the front side (the upper side in FIGS. 5 and 6) of the transfer case 20, and the opening 20h is formed.
Is covered with a cover member 50 detachably attached by a bolt member Bt4. The cover member 50 is preferably provided with a plurality of radiating fins 51 as cooling means for lowering the temperature inside the transfer case 20. Is provided. The heat radiation fins 51 are integrally formed on the front side of the lid member 50, as shown in detail in FIG. In the present embodiment, the lid member 50 is formed by casting a light alloy such as an aluminum alloy, for example, and the radiation fins 51 are integrally formed during the casting. As can be clearly seen from FIG. 9, a flange 50f is formed on the peripheral portion on the bottom side of the lid member 50 for coupling to the transfer case 20 side.
At 0f, a number of bolt insertion holes 50h through which the bolt member Bt4 is inserted are provided.

More preferably, the cover member 50 is provided with a breather device 55 for preventing the inside of the transfer case 20 from being pressurized above a certain level in order to adjust the pressure difference between the inside and outside of the transfer case 20. ing.
The lid member 50 is formed in a substantially rectangular shape in plan view, and has a convex breather chamber 5 protruding to the front side near one corner thereof.
6 are provided. As can be clearly understood from FIG. 10, the breather device 55 is provided on the side wall of the breather chamber 56.
Is provided with a screw hole 57 for screwing and fixing. Since the breather device 55 is the same as a conventionally well-known device, a detailed description of its internal structure, operation, and the like will be omitted.

In the vicinity of the breather chamber 56, an oil suppressing plate 60 (shown by a two-dot chain line phantom line in FIGS. 8 and 10) for suppressing splashed oil from entering the breather chamber 56 is fixedly fastened. Screw holes 58 are provided. The restraining plate 60 is disposed so as to cover most of the lower part of the breather chamber 56 except for the end, and is fastened using a bolt member 59 with a predetermined gap Y provided at the end of the breather chamber 56. Fixed.

In the present embodiment, more preferably, when the cover member 50 is assembled to the transfer case 20, the breather device 55 is relatively moved from the output gear 16 as can be clearly understood from FIGS. Located on the far side,
The radiating fins 51 as the cooling means are connected to the output gear 1.
6 so that the breather device 55
And the radiation fins 51 are provided for the lid member 50. At this time, the gap Y between the oil suppression plate 60 and the wall of the breather chamber 56 is located at a position farthest from the output gear 16.

In the above configuration, a method of assembling the transfer unit Tf to the transfer case 20 and a method of assembling the transfer case 20 to the torque converter housing 2A will be described below.
explain. In the present embodiment, the transfer shaft 15, the transfer output shaft 18, the hypoid gear set 16, 1
After assembling the transfer unit Tf including the components such as 7 into the transfer case 20 in advance to form the sub-assembly body As, the sub-assembly body is assembled to the torque converter housing 2A side.

This assembling is performed in the following procedure. First, a pair of bearings J supporting the transfer output shaft 18 with respect to the cylindrical portion 42 of the transfer case 20.
4, J5 (tapered roller bearing) is assembled, and a standard model (not shown) of the transfer output shaft 18 is inserted to apply a preload to the bearing J4. In this state, the transfer shaft 15
By measuring the distance between the axial center position of the bearing and the inner ring end face of the bearing J4, the inner ring end face of the bearing J4 and the pinion gear 17 are measured.
The thickness of the shim CM1 (first shim) to be interposed between the back side and the back side is set. A plurality of shims CM1 having different thicknesses are prepared, and the one having the thickness closest to the set value is selected from among them. After setting the thickness of the first shim CM1 in this manner, the standard model (not shown) is extracted, and the selected first shim CM1 is mounted on the transfer output shaft 18 to be actually incorporated. This is inserted into the cylindrical portion 42 of the transfer case 20 and incorporated. Then, the companion flange 19 is fastened and fixed to the shaft end of the transfer output shaft 18 using the nut 39. In the present embodiment, the transfer case 20
Since the opening 20h is provided on the front surface side, the work of inserting the transfer output shaft 18 and its standard model (not shown) into and out of the cylindrical portion 42 can be performed extremely easily.

Next, the output gear 16 is non-rotatably mounted to a predetermined portion in the middle of the hollow member 35 (a portion close to the mounting position of the left tapered roller bearing J2 in the figure) by, for example, spline fitting. Thereafter, the tapered roller bearings J2, J
Press-fit and fix the inner ring No. 3. The step of fixing the output gear 16 and the inner rings of the tapered roller bearings J2 and J3 to the outer peripheral side of the hollow member 35 may be performed prior to or in parallel with the above-described steps. And tapered roller bearings J2, J
In addition to combining the outer ring with the inner ring of No. 3 and setting the second shim Cm2 and the third shim Cm3 outside each of the outer ring of the tapered roller bearings J2 and J3, the tapered roller bearing J
The hollow member 35 is set on the base portion 41 such that 2, 2 and J3 are held in the shaft supporting portions 41b and 41c of the base portion 41 of the transfer case 20. At this time, the axial position of the output gear 16 is preliminarily (to some extent) defined by the second shim Cm2 and the third shim Cm3. Also in this case, the work of setting the hollow member 35 and the components attached thereto into the transfer case 20 is performed by the opening 20h on the front side of the transfer case 20.
Can be easily performed.

In this state, a tooth contact inspection (preliminary inspection) of the hypoid gear set (a combination of the output gear 16 and the pinion gear 17) is performed. When the tooth contact is not good, the thickness of the second and third shims Cm2 and Cm3, specifically, for example, those having an appropriate thickness for the second shim Cm2 are selected and replaced. The axial position is preliminarily defined, and the tooth contact with the pinion gear 17 is readjusted. That is, the tooth contact inspection of the hypoid gear sets 16 and 17 can be performed without assembling the transfer shaft 15. In addition, the readjustment operation when the inspection is rejected is easy before the transfer shaft 15 is assembled.

When a good tooth contact is obtained in the preliminary inspection, the cylindrical roller bearing J1 is mounted on the shaft support 41a of the base 41 of the transfer case 20, and the shaft support 41a supporting the cylindrical roller bearing J1 is provided.
The seal member S1 is mounted in a ring groove positioned between the tapered roller bearing J2 and 41b supporting the tapered roller bearing J2. Further, a fourth shim Cm4 mounted outside the inner ring of the tapered roller bearing J2 is set on the transfer shaft 15. Above, this transfer shaft 15 is non-rotatably assembled from the outside of the transfer case 20 (left side in FIGS. 5 and 6) to the inner peripheral side of the hollow member 35 by, for example, spline fitting.
The mounting work of the cylindrical roller bearing J1 and the seal member S1 may be performed in advance.

Thereafter, a fifth shim Cm5 arranged outside the inner ring of the bearing J3 is set on the outer peripheral portion on the shaft end side of the transfer shaft 15, and a nut member 44 is screwed onto the shaft end of the transfer shaft 15. And tighten it with the specified torque.
Thus, the axial position of the output gear 16 is finally determined, and a predetermined axial load (preload) is applied to the tapered roller bearings J2 and J3. Then, in this state, a tooth contact inspection (final confirmation inspection) of the hypoid gear set (a combination of the output gear 16 and the pinion gear 17) is performed. If the final tooth contact inspection fails, for example, the fourth shim CM4 is replaced with one having a different thickness and reassembled to obtain an appropriate tooth contact.

If the final tooth contact inspection has passed, the shaft support portions 41 of the tapered roller bearings J2 and J3
Each cap member 43 is combined with b and 41c, and each cap member 43 is fastened and fixed by tightening the bolt member Bt5. This completes the incorporation of the transfer unit Tf including the components such as the transfer shaft 15, the transfer output shaft 18, and the hypoid gear sets 16, 17 into the transfer case 20.

Thereafter, a cover member 45 for covering the outer side of the transfer shaft 15 on the terminal side is attached to the transfer case 20 on the side surface of the transfer case 20. The opening 2 on the front side of the transfer case 20
The cover member 50 is set at 0h, and fastened and fixed with the bolt member Bt4. Thus, the assembly of the sub-assembly body As is completed.

The sub-assembly As
To the torque converter housing 2A from the side. This assembling operation is performed by inserting the sub-assembly body As from the side while adjusting the meshing state between the input gear 14 and the second ring gear 13. Then, as shown in FIGS. 2, 3, 4 and 7,
By tightening a plurality of (for example, four) bolt members Bt3, the sub-assembly body As is fixed to the torque converter housing 2A. At this time, both positions are set so that the transfer shaft 15 does not cross the rotation surface of the final ring gear 6 (first ring gear).

As described above, according to the present embodiment, the input shaft 14 is provided at one end outside the support position of the three bearings J1 to J3 of the transfer shaft 15, so that the transfer shaft 15 is supported. Since the structure is so-called cantilever support with respect to the load input point, the positions of the transfer shaft 15 and the transfer shaft 15 do not cross the rotation surface of the final ring gear 6 (first ring gear) as compared with the case of the double-support structure. The setting is extremely easy, the diameter of the final ring gear 6 is no longer limited by the presence of the transfer shaft 15, and even when the distance between the output shaft 4 of the transmission Tm and the front wheel axle 8 is determined. The degree of freedom in setting the reduction ratio between the output gear 5 of the transmission Tm and the final ring gear 6 can be greatly increased. Moreover, in this case, the hypoid-type output gear 16 that transmits the driving force of the engine En to the transfer output shaft 18 is disposed close to the central bearing J2 of the three bearings J1 to J3. The radial displacement of the output gear 16 can be effectively restricted, and the change in tooth contact of the hypoid gear set (the combination of the output gear 16 and the pinion gear 17) can be reduced. That is, while maintaining the effect of the transfer shaft 15 having the cantilever support structure, the noise in the hypoid gear sets 16 and 17 can be reduced, and the life of the gear can be improved.

After assembling the transfer unit Tf to the transfer case 20 in advance to form the sub-assembly As, the sub-assembly As is assembled to the transmission Tm side (specifically, the torque converter housing 2A). Therefore, the workability of assembling the transfer unit Tf can be improved. Moreover, in this case, a hollow member 35 having a predetermined length is provided on the outer peripheral side of the transfer shaft 15 so as to be non-rotatable with respect to the transfer shaft 15.
Are rotatably supported on the transfer case 20 via bearings J2 and J3,
The transfer output shaft 1 is provided in the middle of the hollow member 35.
Since the output gear 16 for transmitting the driving force to the drive gear 8 is mounted, the tooth contact inspection of the hypoid gear sets 16 and 17 can be performed without assembling the transfer shaft 15. Therefore, the tooth contact inspection itself can be easily performed, and a readjustment operation can be easily performed when the tooth contact inspection fails.

In particular, since the bearings J2 and J3 supporting both ends of the hollow member 35 or the vicinity thereof are tapered roller bearings having high rigidity in the axial direction, the hypoid type output gear 16 attached to the hollow member 35 is used. Can be defined more accurately.

Further, the tapered roller bearings J2, J3
Since the shims Cm2 to Cm5 for adjusting the tooth contact of the hypoid gear sets 16 and 17 are arranged outside the shaft, the axial position of the hypoid type output gear 16 can be more accurately defined.

Further, with respect to the transfer shaft 15 whose rotation is supported by the three bearings J 1 to J 3, two bearings J 1 are provided between the output gear 16 for transmitting the driving force to the transfer output shaft 18 and the input gear 14. , J2 in which the radial displacement of the transfer shaft 15 is strongly restricted.
1 and J2, the input gear 1 communicating with the transmission Tm side.
Since the seal member S1 that seals the space on the fourth side and the space on the side of the output gear 16 of the hypoid type in a liquid-tight manner is disposed, the deformation of the seal member S1 when the transfer shaft 15 rotates while receiving the transfer load is effectively suppressed. It is possible,
The life of the seal member S1 can be further improved.

According to the present embodiment, more preferably, the cooling means (radiation fins 51) for lowering the temperature in the transfer case 20 is provided on the detachable lid member 50, so that the transfer shaft The difference in the temperature raising condition in the transfer case 20, such as the rotation range of the engine 15, the heat radiation condition of the engine En, and the positional relationship with the engine En, can be dealt with by changing only the lid member 50. Therefore, it is possible to share the transfer case 20 without having to consider the temperature rising condition in the transfer case 20.

In particular, since the cooling means is constituted by the radiating fins 51, the structure thereof is simple, and
Since the cooling means 51 is manufactured by casting, the cooling means 51 can be easily formed integrally during the manufacturing.

Furthermore, since the breather device 55 is provided on the detachable lid member 50, the necessity of the breather device 55 can be dealt with by changing only the lid member 50. Therefore, the transfer case 20 can be shared without having to consider the necessity of the breather device 55.

Further, a cooling means 51 for lowering the temperature inside the transfer case 20 is provided on the lid member 50.
(Radiation fins) and a breather device 55 for preventing the inside of the transfer case 20 from being pressurized above a certain level. The breather device 55 is disposed relatively far from the hypoid gear sets 16 and 17 by the cooling means 51. Are disposed relatively close to the hypoid gear sets 16 and 17, respectively. That is, the breather device 55
Are located relatively far from the hypoid gear sets 16 and 17 and have less scattered oil due to their meshing rotation, so that oil from the breather device 55 to the outside of the transfer case 20 and clogging of the breather device 55 can be prevented. Failures can be effectively prevented. In particular, the lower part of the breather chamber 56 is largely covered with an oil suppressing plate 60, and the gap Y between the oil suppressor 60 and the wall of the breather chamber 56 is located at a position farthest from the hypoid gear sets 16 and 17. Therefore, it is possible to more effectively prevent the oil from scattering into the breather chamber 56. On the other hand, the cooling means 51 (radiation fins) are relatively close to the hypoid gear sets 16 and 17 and are arranged in a place where the scattered oil is large, so that the lubricating oil in the transfer case 20 can be cooled more effectively. Can be. That is, the cooling means 51 (radiation fins) and the breather device 55 can be appropriately arranged in accordance with the position where the scattered oil is generated due to the meshing rotation of the hypoid gear sets 16 and 17, and the respective functions are effectively exhibited. Can be done.

Further, according to the present embodiment, the transfer unit Tf is previously assembled to the transfer case 20 to form the sub-assembly As, and the sub-assembly As is assembled to the transmission Tm. Preferably, the cooling means 51 (radiation fins) and the breather device 55 can be provided using the lid member 50 that covers the opening 20h used when assembling the transfer unit Tf into the transfer case 20. is there.

Although the above embodiment has been described with reference to a case where the present invention is applied to a vehicle equipped with an automatic transmission, the present invention is not limited to such a case.
Even when the transmission is a manual transmission type, it can be effectively applied. In addition, the present invention is not limited to the above embodiments, and without departing from the gist thereof,
It goes without saying that various improvements, modifications or changes in design are possible.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram schematically showing a configuration of a power transmission device for a four-wheel drive vehicle according to an embodiment of the present invention.

FIG. 2 is an explanatory side view of the power transmission device.

FIG. 3 is an explanatory sectional view taken along line III-III in FIG. 2;

FIG. 4 is an explanatory sectional view taken along line IV-IV in FIG. 2;

FIG. 5 is an explanatory cross-sectional view showing a transfer structure of the four-wheel drive vehicle according to the embodiment.

FIG. 6 is an explanatory cross-sectional view showing an enlarged main part of a transfer structure of the four-wheel drive vehicle.

FIG. 7 is an explanatory side view of a transfer structure of the four-wheel drive vehicle.

FIG. 8 is an explanatory cross-sectional view of a lid member of a transfer case.

FIG. 9 is an explanatory bottom view of the lid member.

FIG. 10 is an explanatory sectional view taken along line XX in FIG. 9;

[Explanation of symbols]

 2A: Torque converter housing 14: Input gear of transfer shaft 15: Transfer shaft 16: Output gear of transfer shaft 17: Pinion gear 18: Transfer output shaft 20: Transfer case 35: Hollow member As: Sub-assembly Cm2 to Cm5: Shim En ... Engines J1 to J3 ... Bearing S1 ... Seal member Tf ... Transfer unit Tm ... Transmission

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroaki Hayashi 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd.

Claims (6)

[Claims] 1. A vehicle comprising: a single transfer shaft arranged in a vehicle width direction; a transfer output shaft extending in a direction perpendicular to the shaft; and a bevel gear set provided between these two shafts. The transfer shaft is rotatably supported via bearing members at three points near and at both ends with respect to the case body, and an input gear receiving driving force from the engine is provided at one end outside the supporting position of the bearing members. In a transfer structure for a four-wheel drive vehicle, a bevel gear for transmitting a driving force to the transfer output shaft is disposed close to a central bearing member among the three. Car transfer structure. 2. A transfer shaft provided with an input gear receiving a driving force transmitted from a transmission-side unit, a transfer output shaft extending in a direction perpendicular to the shaft, and an umbrella provided between these two shafts. After a transfer unit having a gear set is assembled in a transfer case in advance to form a sub-assembly body, the sub-assembly body is assembled to the transmission-side unit.
In a transfer structure of a wheel drive vehicle, a hollow member having a predetermined length is provided on the outer peripheral side of the transfer shaft so as to be non-rotatable with respect to the transfer shaft, and both ends of the hollow member or the vicinity thereof are provided via a bearing member. It is supported rotatably with respect to the transfer case,
A transfer structure for a four-wheel drive vehicle, characterized in that a bevel gear for transmitting a driving force to the transfer output shaft is mounted at an intermediate portion of the hollow member. 3. The transfer structure for a four-wheel drive vehicle according to claim 2, wherein said bearing member is a tapered roller bearing. 4. The transfer of a four-wheel drive vehicle according to claim 2, wherein a shim for adjusting the tooth contact of the bevel gear set is disposed outside the bearing member. Construction. 5. The transfer case is rotatably supported at three points near and at both ends of the transfer case via a bearing member, and is transmitted from the transmission-side unit to one end outside the supporting position of the bearing member. A transfer case including a transfer shaft provided with an input gear for receiving a driving force, a transfer output shaft extending in a direction perpendicular to the shaft, and a bevel gear set provided between the two shafts. After a sub-assembly body is constructed by assembling the sub-assembly body, the sub-assembly body is assembled to the transmission-side unit. In the transfer structure of a four-wheel drive vehicle, a hollow member having a predetermined length is provided on the outer peripheral side of the transfer shaft. The hollow member is disposed so as to be non-rotatable with respect to the shaft. Is rotatably supported with respect to the transfer case,
A four-wheel drive vehicle characterized in that a bevel gear for transmitting a driving force to the transfer output shaft is attached to a middle part of the hollow member so as to be close to a central bearing member among the three. Transfer structure. 6. A single transfer shaft disposed in a vehicle width direction, a transfer output shaft extending in a direction perpendicular to the shaft, and a bevel gear set provided between the two shafts. The transfer shaft is rotatably supported via a bearing member at three points near and at both ends of the transfer case via a bearing member, and the driving force transmitted from the transmission unit to one end outside the supporting position of the bearing member. In a transfer structure of a four-wheel drive vehicle provided with a receiving input gear, two bearings are arranged between the bevel gear for transmitting a driving force to the transfer output shaft and the input gear, and the bearing is disposed between the bearings. A transfer structure for a four-wheel drive vehicle, characterized in that a seal member for sealing a liquid-tight seal between an input gear side space and a bevel gear side space communicating with the transmission side is arranged.