JP6346515B2 - Power transmission device - Google Patents

Description

  The present invention relates to a power transmission device.

  The viscous joint is used as a part of a power transmission device of an automobile, and a typical application example is one arranged on an input shaft of a final reduction device of a four-wheel drive vehicle. The viscous joint is arranged in the power transmission path on the side that is not the main drive wheel, transmits power to one of the front wheels or the rear wheel during normal driving, and when the main drive wheel slips on a snowy road or muddy ground, It is a joint that transmits power. As a result, the driving performance of four-wheel drive is imparted to an automobile without causing deterioration of fuel consumption by driving with two wheels.

  In a four-wheel drive vehicle based on front wheel drive, the viscous joint is generally arranged between the propeller shaft and the final reduction gear. As an example of a viscous joint, an outer plate and an inner hub that rotate integrally with the outer case, which are alternately arranged in a space formed by the outer case, an inner hub that rotates relative to the outer case, and the outer case and the inner hub And an inner plate that rotates integrally with the cover and a cover that seals the opening of the outer case. The space is filled with high viscosity silicone oil at a constant ratio.

  As described above, when the front wheel slips, a relative rotation occurs between the outer plate and the inner plate, and shear force acts on the silicone oil interposed between the plates to transmit power between the plates, and power is transmitted to the rear wheel. Is done. Thus, the viscous joint has a structure in which power is transmitted when a difference in rotational speed occurs between the front and rear wheels. Therefore, for example, even if there is a slight difference in the number of revolutions between the front and rear wheels due to the tire wear state, load capacity, etc., that is, although the two-wheel drive is sufficient, the four-wheel drive state is set. There is a risk that the fuel consumption will deteriorate.

  In order to solve this problem, a technique is known in which a power interrupting device is disposed between the viscous joint and the final reduction gear so that the four-wheel drive state can be arbitrarily stopped. For example, in Patent Document 1, a final reduction gear is arranged in the rear final reduction housing, a viscous coupling is arranged in a fluid coupling housing in front of the rear reduction gear housing, and a power interrupting device is arranged between the final reduction gear and the viscous coupling. The technology is described.

No. 7-40408

The structure described in Patent Document 1 has the following problems.
(1) The technique of patent document 1 has connected the propeller shaft and the inner hub of a viscous coupling. Usually, since the inner hub is composed of a cylindrical member having a smaller diameter than the propeller shaft, a dedicated connecting member (companion flange) for connecting the propeller shaft and the inner hub is required. In addition, a lock nut for fixing the drive pinion shaft to the inner hub is required, and the assembly work is troublesome because screwing work is required.

  (2) Basically, the lubricating structure of the final reduction gear is such that the ring gear scoops up the lubricating oil stored at the bottom of the housing, and supplies the splashed oil to the portion requiring lubrication. Since the bearings arranged around the viscous joint and the power interrupting device are located away from the ring gear, a sufficient amount of lubricating oil may not be supplied to these bearings.

  (3) Since the viscous joint is structured to be accommodated inside the housing, the housing is increased in size. As a result, the weight of the power transmission device increases and the degree of freedom of the body layout is hindered. Further, when the viscous joint continues to operate, the temperature becomes high due to the shearing motion of the internal fluid. In the structure of Patent Document 1, since the viscous joint is structured to be oil bathed in the lubricating oil of the final reduction gear in the housing, when the temperature of the viscous coupling rises, the lubricating oil of the final reduction gear also rises. Generally, high temperature seal members are used in viscous joints. However, if the lubricating oil of the final reduction gear rises, it will be necessary to use a high temperature compatible material for the final reduction gear seal. Become.

  The present invention was created to solve such problems, and an object of the present invention is to provide a power transmission device that has a small number of parts and is easy to assemble.

In order to solve the above-described problems, the present invention provides a power coupling in which a viscous coupling is interposed between a propeller shaft and a drive pinion shaft, and power is transmitted and disconnected between the viscous coupling and the drive pinion shaft. A power transmission device including an outer case and an inner hub that form a viscous fluid working chamber, wherein the drive pinion shaft and the viscous coupling are coaxial. And the power interrupting device includes a first hub that rotates integrally with the inner hub, and a second hub that rotates integrally with the drive pinion shaft and intermittently connects to the first hub. , and a switching sleeve intermittently and said second hub and said first hub, the first hub and the second hub is connected by the switching sleeve When the inner hub and the drive pinion shaft rotates together, when by the switching sleeve and said first hub and the second hub is disconnected, that the said inner hub and said drive pinion shaft is disconnected Features.

  Since the power interrupting device of the present invention has a structure in which the inner hub of the viscous joint and the drive pinion shaft rotate relative to each other, a lock nut for fixing the drive pinion shaft to the inner hub is not required as in the prior art. Therefore, the power transmission device can be easily assembled. In general, since the outer case of the viscous joint is a large and thick cylindrical member, the propeller shaft and the outer case can be directly connected without requiring a companion flange. Therefore, the number of parts is reduced and the power transmission device can be easily assembled.

  Further, the present invention is characterized in that the drive pinion shaft is inserted through the inner hub, and the periphery of the tip of the drive pinion shaft is supported by the inner hub via a shield bearing.

  According to this configuration, the drive pinion shaft can be supported on the inner hub with a simple structure by the intervention of the shield bearing, and the shaft runout between the drive pinion shaft and the inner hub, that is, the first hub and the second hub can be supported. Shake with the hub can be prevented. And the problem of insufficient supply amount of lubricating oil does not arise by making a bearing for support into a shield bearing.

  The first hub may be splined to the inner hub and supported by the drive pinion shaft through a shield bearing.

According to the said structure, the integral rotation structure of a 1st hub and an inner hub can be simplified. Since the first hub is supported on the drive pinion shaft via the shield bearing, it is possible to prevent the shaft runout between the first hub and the second hub attached to the drive pinion shaft.
And the problem of insufficient supply amount of lubricating oil does not arise by comprising the bearing between a 1st hub and a drive pinion shaft from a shield bearing.

  Further, the present invention is characterized in that the outer case is arranged outside a case incorporating the power interrupting device and the drive pinion shaft.

  According to this configuration, since the viscous joint is disposed outside the case, the case can be reduced in size and weight, and the influence on the vehicle layout can be suppressed. Further, there is no problem that the temperature of the lubricating oil in the case rises due to the temperature rise of the viscous joint when the viscous joint is arranged inside the case.

Further, the present invention is characterized in that the drive pinion shaft is a drive pinion shaft of a final reduction gear.
Further, the present invention is characterized in that the drive pinion shaft is a drive pinion shaft of a four-wheel drive auxiliary transmission device that distributes power to front wheels and rear wheels.

  According to the present invention, a power transmission device with a small number of parts and easy assembly work is provided.

It is a plane sectional view of the power transmission device concerning the present invention. It is a plane sectional view around a viscous joint and a power interruption device in the present invention, and shows a state where a power transmission device is in a cutting state. It is a plane sectional view around a viscous coupling and a power interruption device in the present invention, and shows a state where a power transmission device is in a connected state.

  An embodiment in which the present invention is applied to a final reduction gear for driving rear wheels will be described. In FIG. 1, a power transmission device 1 according to the present invention includes a viscous joint 40 interposed between a propeller shaft (not shown) and a drive pinion shaft 71 of a final reduction gear 70, and the viscous joint 40 and the drive pinion shaft 71. A power interrupting device 2 for transmitting / disconnecting power to / from the power source is interposed. The power of a prime mover (not shown) arranged on the front side of the four-wheeled vehicle is input to the drive pinion shaft 71 via a transmission and a propeller shaft (not shown), the viscous joint 40, and the power interrupting device 2.

"Final decelerator 70"
The final reduction gear 70 includes a drive pinion shaft 71 that rotates about the rotation axis O1 along the vehicle longitudinal direction, a drive pinion gear 72 formed at the rear end of the drive pinion shaft 71, and a ring gear 73 that is orthogonally engaged with the drive pinion gear 72. The differential gear 80 rotates integrally with the ring gear 73, and a case 74 that accommodates these elements. As will be described later, the case 74 is divided into three cases of a first case 74A to a third case 74C.

  The drive pinion shaft 71 has a truncated cone drive pinion gear 72 formed at the rear end thereof. The drive pinion gear 72 meshes perpendicularly with the ring gear 73, whereby the power of the drive pinion shaft 71 is deflected by 90 ° and transmitted to the left and right rear wheels. The drive pinion shaft 71 is rotatably supported by the second case 74B (case front portion 74Bb) via a front tapered roller bearing 75 and a rear tapered roller bearing 76. A collapsible spacer 77 is interposed between the tapered roller bearing 75 and the tapered roller bearing 76. The collapsible spacer 77 has a cylindrical shape, is a component that can be elastically deformed in the axial direction (front-rear direction), and applies axial preload to the tapered roller bearings 75 and 76. Between the taper roller bearing 76 and the drive pinion gear 72, a shim 78 for adjusting the position of meshing between the drive pinion gear 72 and the ring gear 73 is interposed.

"Differential gear 80"
The differential device 80 includes a differential case 81, two side gears 82 arranged coaxially with the rotation axis O <b> 2 of the differential case 81, two pinion gears 83 that are orthogonally engaged with the side gears 82, and through holes formed in the pinion gear 83. And a pinion shaft 84 that is inserted and fitted into the differential case 81.

  The differential case 81 is rotatably supported by the first case 74A and the second case 74B via two tapered roller bearings 85. A shim 92 for adjusting the preload of the tapered roller bearing 85 is interposed between the tapered roller bearing 85 and the first case 74A and the second case 74B. The differential case 81 rotates about a rotation axis O2 extending in the left-right direction. The differential case 81 is formed in a spherical shell-shaped differential case body 86 and cylindrical ends that are respectively formed at both ends of the differential case body 86 and supported by the tapered roller bearing 85. Boss portions 87 and 87 and a ring-shaped flange portion 88. The ring gear 73 is fastened to the flange portion 88 by bolts 89, whereby the ring gear 73 and the differential case 81 rotate integrally around the rotation axis O2.

  The differential case main body 86 has a gear accommodating chamber for accommodating the pinion gear 83 and the side gear 82 therein. In the differential case main body 86, the pinion shaft 84 extends in a direction orthogonal to the rotation axis O <b> 2 and both ends thereof are fixed to the differential case main body 86. Each pinion gear 83 is rotatably attached to the pinion shaft 84 with the pinion shaft 84 as a center of rotation. Each side gear 82 is arranged to be rotatable about the rotation axis O2 on the left side or the right side of the pinion shaft 84, and meshes with the two pinion gears 83 and 83. A thrust washer 90 is interposed between the rear surface (axial outer surface) of each side gear 82 and the differential case body 86.

  A drive shaft (not shown) that rotates in conjunction with the left or right rear wheel is inserted into the rear surface of each side gear 82, and the side gear 82 and the drive shaft are connected by spline coupling. Rotate together. The left or right drive shaft is inserted through the hollow portion of each boss portion 87. A spiral oil guide groove 91 is formed on the inner peripheral surface of each boss portion 87.

"Case 74"
The case 74 according to the present embodiment is attached to the front end of the first case 74A near the rear, the second case 74B near the front, and the front end of the second case 74B, which are divided by using a plane parallel to the rotation axis O2. 3 cases 74C. The first case 74 </ b> A and the second case 74 </ b> B are joined to each other by bolts (not shown) with their divided surfaces being matched.

  The first case 74 </ b> A has a substantially semi-cylindrical shape with openings at the front end and the left and right ends, and accommodates the rear half of the differential device 80. The second case 74B generally includes a case rear part 74Ba whose rear end and both left and right ends are open, a substantially cylindrical case middle part 74Bb extending forward from the front part of the case rear part 74Ba, and a front part of the case middle part 74Bb. It has a shape provided with a case front portion 74Bc having an enlarged diameter and a front end opened. The case rear portion 74Ba accommodates the periphery of the front half of the differential device 80. The case middle portion 74Bb accommodates the rear side of the drive pinion shaft 71. The case front portion 74Bc accommodates the middle of the drive pinion shaft 71 and the rear side of the power interrupting device 2.

  The third case 74C is a member having an opening formed at the rear end. The opening edge of the third case 74C is aligned with the opening edge of the case front portion 74Bc of the second case 74B and is fastened and fixed to each other by a bolt 93. A through hole for passing the inner hub 43 is formed in the front portion of the third case 74C. The third case 74C accommodates the front side of the power interrupting device 2.

  The case front portion 74Bc and the third case 74C of the second case 74B are formed such that the left side swells outward in the vehicle width direction from the right side with the rotation axis O1 interposed therebetween. A switching sleeve moving mechanism 10 to be described later is accommodated in the bulged portion.

"Viscous joint 40"
As shown in FIG. 2, the viscous joint 40 is a cylindrical outer case 42 having a bottom wall portion 41 on the front side, and a cylindrical shape that is disposed on the center axis (rotation axis O1) line of the outer case 42 and extends in the front-rear direction. The inner hub 43, a plurality of outer plates 45 and inner plates 46 accommodated in a differential chamber 44 formed between the outer case 42 and the inner hub 43, and a ring-shaped cover 47 are provided. The viscous joint 40 and the drive pinion shaft 71 are arranged coaxially on the rotation axis O1 and overlapped in the direction of the rotation axis O1. The front end of the outer case 42 is directly connected to the rear end of a propeller shaft (not shown). Thereby, the outer case 42 rotates integrally with the propeller shaft. The outer case 42 is disposed outside the case 74, and in front of the third case 74C in the present embodiment.

  A small inner diameter portion 48 is formed in the bottom wall portion 41 of the outer case 42 so as to be in sliding contact with the outer peripheral surface of the inner hub 43. A shaft seal member 49 and a bearing 50 are interposed between the small inner diameter portion 48 of the outer case 42 and the outer peripheral surface of the inner hub 43. The shaft seal member 49 is fitted in an annular groove formed in the small inner diameter portion 48 of the outer case 42. The shaft seal member 49 is located between the differential chamber 44 and the bearing 50, and prevents silicone oil (viscous fluid) from leaking from the differential chamber 44 to the bearing 50. The bearing 50 has a rear side in contact with the stepped portion of the inner peripheral surface of the outer case 42 for the outer ring and a front side in contact with a snap ring 52 attached to the inner peripheral surface of the outer case 42. The outer side surface of the inner hub 43 is in contact with the stepped portion and the front side surface is in contact with the snap ring 53 attached to the outer peripheral surface of the inner hub 43 so that the outer case 42 and the inner hub 43 cannot move in the axial direction. . The bearing 50 is a shield bearing. “Shield bearing” refers to a bearing in which a ball or roller located between an inner ring and an outer ring is blocked from the outside by a seal and slides by lubrication of grease sealed inside.

  An inner diameter portion near the rear end of the outer case 42 is formed as a large inner diameter portion 51, and an annular differential chamber 44 is formed by the large inner diameter portion 51, the outer peripheral surface of the inner hub 43 and the cover 47. In the differential chamber 44, an outer plate 45 splined to the inner peripheral surface of the large inner diameter portion 51 of the outer case 42 and an inner plate 46 splined to the outer peripheral surface of the inner hub 43 are in a direction along the rotation axis O1. Are housed in an alternately stacked state.

  In the outer case 42, the inner diameter portion closer to the other end than the large inner diameter portion 51 is formed as a cover fitting diameter portion 54 having a larger diameter than the large inner diameter portion 51. A ring-shaped cover 47 in which a hole through which the inner hub 43 is inserted is formed at the center of the center. The cover 47 is fixed to the outer case 42 by a snap ring 55. A shaft seal member 56 and a bearing 57 are interposed between the inner diameter portion of the cover 47 and the outer peripheral surface of the inner hub 43. The shaft seal member 56 is the same member as the shaft seal member 49 and is fitted in an annular groove formed in the inner diameter portion of the cover 47. The shaft seal member 56 is located between the differential chamber 44 and the bearing 57 and prevents silicone oil from leaking from the differential chamber 44 to the bearing 57. An O-ring 58 is also provided between the cover 47 and the outer case 42 to prevent leakage of silicone oil.

  The cover 47 is formed with a filling hole 59 for filling the working chamber 44 with silicone oil and an air vent hole 60 for letting the air in the working chamber 44 escape to the outside when the silicone oil is filled. ing. An internal thread is screwed into the filling hole 59, and the filling hole 59 is closed by a bolt 61 after filling with silicone oil. The bolt 61 is, for example, a hexagon socket head bolt having a hexagon hole. The air vent hole 60 is closed when a steel ball 62 is press-fitted.

  The rear end of the inner hub 43 protrudes rearward from the outer case 42, and an oil seal 63 is provided between the protruding portion and the third case 74C. The oil seal 63 seals the lubricating oil in the case 74.

  The drive pinion shaft 71 is inserted into the inner hub 43 so that the front end (tip) thereof is substantially at the same position as the front end of the inner hub 43. A bearing 64 is provided between the outer peripheral surface around the front end of the drive pinion shaft 71 and the inner peripheral surface around the front end of the inner hub 43. That is, the periphery of the tip of the drive pinion shaft 71 is supported by the inner hub 43 via the bearing 64. The bearing 64 is disposed at a position overlapping the bearing 50 in the vehicle longitudinal direction. The bearing 64 cannot move in the axial direction because the rear side surface of the outer ring is in contact with the step portion of the inner peripheral surface of the inner hub 43 and the front side surface of the inner ring is in contact with the snap ring 65 attached to the outer peripheral surface of the drive pinion shaft 71. It is said. The bearing 64 is a shield bearing.

"Power interrupting device 2"
The power interrupting device 2 includes a first hub 3 that rotates integrally with the inner hub 43, a second hub 4 that rotates integrally with the drive pinion shaft 71 and intermittently connects to the first hub 3, and the first hub 3 and the second hub 2. A switching sleeve 9 for connecting and disconnecting the hub 4 is provided.

  The second hub 4 is a substantially disk-shaped member having a through hole formed at the center, and a spline formed on the inner peripheral surface of the through hole is formed on the outer peripheral surface of the drive pinion shaft 71. By being coupled, it rotates integrally with the drive pinion shaft 71. A spline 4 </ b> A is formed on the outer peripheral surface of the second hub 4. The rear surface of the second hub 4 is abutted against the front side surface of the inner ring of the tapered roller bearing 75, and the second hub 4 is tightened by a lock nut 7 screwed into the male thread portion of the drive pinion shaft 71 via washers 5 and 6. Thereafter, the flange portion 7 </ b> A at the tip end of the lock nut 7 is caulked in a recess 71 </ b> A formed in the drive pinion shaft 71. Accordingly, the second hub 4 is attached to the drive pinion shaft 71 so as to be integrally rotatable and immovable in the direction of the rotation axis O1.

  On the other hand, the first hub 3 is a substantially cylindrical member having a cylindrical portion 3A and a flange portion 3B extending radially outward from the rear end of the cylindrical portion 3A, and the second hub 4 with respect to the drive pinion shaft 71. It is arranged in front of. Splines 3C are formed on the outer peripheral surface of the flange portion 3B. Splines that are coupled to the splines of the inner hub 43 are formed on the outer peripheral surface of the cylindrical portion 3A. A spline is formed on the inner peripheral surface near the rear end of the inner hub 43, and the first hub 3 is coupled to the spline of the inner hub 43, and the outer peripheral surface of the drive pinion shaft 71 is interposed via the bearing 8. It is attached so that it can rotate relative to it. In the first hub 3, the rear surface of the inner ring of the bearing 8 is in contact with the stepped portion of the outer peripheral surface of the drive pinion shaft 71, and the stepped portion formed in the flange portion 3 </ b> B is in contact with the rear end of the inner hub 43. It is attached to the pinion shaft 71 and the inner hub 43 so as not to move in the axial direction. The bearing 8 is a shield bearing.

  A switching sleeve 9 having a ring shape is splined to the spline 4A of the second hub 4 by a spline 9A formed on the inner peripheral surface thereof. An annular arm engagement groove 9 </ b> B is formed on the outer peripheral surface of the switching sleeve 9. The switching sleeve 9 is coupled only to the spline 4A of the second hub 4 and not to the spline 3C of the first hub 3 when in the cutting position P1, which is the rear position, and to the connection position P2 which is the front position. In some cases, both the spline 4A of the second hub 4 and the spline 3C of the first hub 3 are coupled.

"Switching sleeve moving mechanism 10"
An example of the switching sleeve moving mechanism 10 for moving the switching sleeve 9 along the rotation axis O1 will be described. The switching sleeve moving mechanism 10 includes a motor 11, a fork 12 that engages with the arm engagement groove 9 </ b> B of the switching sleeve 9, and a feed screw mechanism that converts the rotational motion of the motor 11 into a linear motion along the rotational axis O <b> 1 of the fork 12. 13.

  The front wall portion of the third case 74C is formed with a cylindrical wall portion 74D that extends rearward in parallel with the rotation axis O1 and penetrates back and forth. The motor 11 is attached to the third case 74C with a bolt (not shown) or the like so that the output shaft 11A is positioned in the cylindrical wall portion 74D. The rod 14 is connected to the output shaft 11A via the adapter 15 so as to rotate integrally therewith. The rod 14 is supported at the front end thereof by the cylindrical wall portion 74D of the third case 74C via the bearing 19, and at the rear end by the second case 74B via the bearing 20.

  The fork 12 includes a cylindrical body portion 12A that is externally fitted to the rod 14 so as to be movable in the axial direction of the rod 14, and an arm portion 12B that extends from the cylindrical body portion 12A toward the switching sleeve 9. The distal end surface of the arm portion 12B is formed in an arc shape that follows the peripheral surface of the arm engagement groove 9B, and the arc-shaped distal end surface engages with the arm engagement groove 9B of the switching sleeve 9, thereby 12 is not rotatable about the axis of the rod 14. A cap 21 is attached to the front end of the cylinder body 12A by screwing.

  A male screw portion 14A is formed on the outer peripheral surface of the rod 14 inside the cylindrical body portion 12A, and a shaft nut 22 is screwed to the male screw portion 14A. The shaft nut 22 has an outer shape in contact with the inner wall portion 12 </ b> C of the cylindrical body portion 12 </ b> C having, for example, an elliptical shape, and is configured so as not to rotate relative to the fork 12 around the axis of the rod 14. Inside the cylindrical body portion 12A, the rod 14 is covered with a first coil spring 23 whose front end abuts on the cap 21 and whose rear end abuts on the flange portion 22B, and the front end abuts on the flange portion 22B. A second coil spring 24 whose end is in contact with the step wall of the cylindrical body portion 12A is externally provided.

With the above configuration, when the rod 14 rotates, the shaft nut 22 disposed so as not to rotate relative to the fork 12 moves in the front-rear direction by the feed screw action, and the force is applied to the first coil spring 23 and the second coil spring. 24 and transmitted to the fork 12. Thereby, the fork 12 moves the switching sleeve 9 between the cutting position P1 and the connection position P2.
As described above, an example of the switching sleeve moving mechanism 10 has been described. As a power source, an air actuator, an electromagnetic clutch, a hydraulic pump may be used in addition to a motor, and a ball cam, a multi-plate clutch, or the like may be used as the switching mechanism. Good.

"Action"
FIG. 2 shows a state in which the switching sleeve 9 of the power interrupting device 2 is splined only to the second hub 4 and is located at the cutting position P1. Therefore, power from the propeller shaft is not transmitted to the drive pinion shaft 71.

  When the rod 14 is rotated by driving the motor 11 from the state of FIG. 2, the shaft nut 22 is moved forward by the feed screw action of the feed screw mechanism 13, and the first coil spring 23 is compressed. The first coil spring 23 is compressed by a predetermined amount, and the elastic restoring force (the force that presses the cap 21) of the first coil spring 23 at that time causes the switching sleeve 9 to be splined in synchronization with the first hub 3. When the required load is exceeded, the fork 12 moves forward. As a result, the switching sleeve 9 moves forward as shown in FIG. 3, and is located at the connection position P <b> 2 that is splined to both the first hub 3 and the second hub 4. As a result, the inner hub 43 of the viscous joint 40 and the drive pinion shaft 71 can be rotated together.

  When the switching sleeve 9 is in the connection position P2 and the rod 14 is rotated in reverse by the drive of the motor 11, the shaft nut 22 is moved backward by the feed screw action of the feed screw mechanism 13, and the second coil spring 24 is compressed. The When the second coil spring 24 is compressed by a predetermined amount and the elastic restoring force of the second coil spring 24 at that time exceeds the load required for the switching sleeve 9 to be detached from the first hub 3, the fork 12 moves rearward. To do. Thereby, the switching sleeve 9 returns to the cutting position P1.

  With the switching sleeve 9 positioned at the connection position P2, the rotational speed difference between the outer case 42 connected to the propeller shaft and the inner hub 43 connected to the drive pinion shaft 71, for example, when the front wheel is idled. Occurs, a shearing force is generated in the silicone oil between the outer plate 45 and the inner plate 46, and power is transmitted between the outer plate 45 and the inner plate 46. As a result, the power from the propeller shaft is transmitted to the final reduction gear 1 via the viscous coupling 40 and the power interrupting device 2, and is transmitted to the rear wheels.

  A conventional power interrupting device has a structure in which a propeller shaft and an inner hub of a viscous joint are connected so as to be integrally rotatable, and a hub that rotates integrally with an outer case of the viscous joint and a hub that rotates integrally with a drive pinion shaft are intermittently connected. Therefore, (1) a lock nut for fixing the drive pinion shaft to the inner hub of the viscous joint is required. (2) Usually, the inner hub is a thin cylindrical member having a smaller diameter than the propeller shaft. There is a problem that a dedicated connecting member (compact flange) is required for connection between the propeller shaft and the inner hub.

On the other hand, the power interrupting device 2 of the present invention has a structure in which the first hub 3 that rotates integrally with the inner hub 43 of the viscous joint 40 and the second hub 4 that rotates integrally with the drive pinion shaft 71 are intermittently connected. That is, since the inner hub 43 and the drive pinion shaft 71 are relatively rotated, the lock nut is not required. Therefore, the power transmission device can be easily assembled.
In general, since the outer case 42 of the viscous joint 40 is a large and thick cylindrical member, the propeller shaft and the outer case 42 of the viscous joint 40 can be directly connected without requiring a companion flange. Therefore, the number of parts is reduced and the power transmission device can be easily assembled.

  The lubricating oil accumulated at the bottom of the case rear portion 74Ba of the first case 74A and the second case 74B is scraped up by the ring gear 73. A part of the lubricating oil that is scraped up is supplied forward in the order of the tapered roller bearing 76 → the tapered roller bearing 75, but the supply amount tends to be insufficient before reaching the power interrupting device 2. On the other hand, by constituting the bearing 8 between the first hub 3 and the drive pinion shaft 71 from a shield bearing sealed with grease, the problem of insufficient supply amount of the lubricating oil can be solved. Further, if the first hub 3 is splined to the inner hub 43, the integral rotation structure of the first hub 3 and the inner hub 43 can be simplified. Since the first hub 3 is supported by the drive pinion shaft 71 via the bearing 8, it is possible to prevent the shaft runout between the first hub 3 and the second hub 4 attached to the drive pinion shaft 71.

  Further, if the drive pinion shaft 71 is inserted into the inner hub 43 and the inner periphery of the drive pinion shaft 71 is supported by the inner hub 43 via the bearings 64, the drive pinion shaft 71 can be connected to the inner hub 43 with a simple structure. The shaft 43 can be supported by the hub 43, and the shaft runout between the drive pinion shaft 71 and the inner hub 43, that is, the shaft runout between the first hub 3 and the second hub 4 can be prevented. In particular, as in the present embodiment, when the bearing 64 is arranged at a position overlapping the bearing 50 in the vehicle longitudinal direction, it is possible to effectively suppress the axial vibration of the outer case 42, the inner hub 43, and the drive pinion shaft 71. . In addition, since the bearing 64 is a shield bearing, the problem of insufficient supply of lubricating oil does not occur.

  Further, since the outer case 42 of the viscous joint 40 is disposed outside the case 74 containing the power interrupting device 2 and the drive pinion shaft 71, the case 74 can be reduced in size and weight, which has an influence on the vehicle layout. Can be suppressed. Further, there is no problem that the temperature of the lubricating oil in the case 74 rises due to the temperature rise of the viscous joint 40 when the viscous joint 40 is disposed inside the case 74.

"Assembly procedure of power transmission device 1"
An example of the assembly procedure of the power transmission device 1 will be described.
(1) The drive pinion shaft 71 is attached to the second case 74B via the tapered roller bearings 75 and 76, the collapsible spacer 77, and the shim 78.
(2) The second hub 4 is splined to the drive pinion shaft 71. As described above, the rear surface of the second hub 4 is in contact with the front side surface of the inner ring of the tapered roller bearing 75. Then, the lock nut 7 is tightened through the washers 5 and 6. At that time, a tightening torque is applied so that the preload of the tapered roller bearings 75 and 76 becomes a predetermined value. Then, the flange portion 7 </ b> A (FIG. 2) at the distal end of the lock nut 7 is caulked in a recess 71 </ b> A formed in the drive pinion shaft 71. Accordingly, the second hub 4 is attached to the drive pinion shaft 71 so as to be integrally rotatable and immovable in the direction of the rotation axis O1.
(3) The front half of the assembled differential device 80 is assembled to the second case 74B via the tapered roller bearing 85 and the shim 92, and the ring gear 73 is engaged with the drive pinion gear 72. Next, the first case 74A is fastened and fixed to the second case 74B with a bolt (not shown). This completes the assembly of the final reduction gear 70.

(4) The bearing 8 is fitted on the drive pinion shaft 71, and the first hub 3 is fitted on the outer ring of the bearing 8.
(5) The fork 12, the rod 14, the cap 21, the shaft nut 22, the first coil spring 23, and the second coil spring 24 are assembled in advance (this is referred to as a fork assembly). In a state where the arm portion 12B of the fork assembly is engaged with the arm engaging groove 9B of the switching sleeve 9, the switching sleeve 9 is splined to the first hub 3 and the second hub 4, and the rear end of the rod 14 Is fitted into the bearing 20 attached to the second case 74B.
(6) Next, the third case 74C is fastened and fixed by the bolts 93 in accordance with the second case 74B so that the front end of the rod 14 is fitted in the bearing 19 attached to the third case 74C. A liquid packing is applied to the mating surface of the second case 74B and the third case 74C.

  (7) The motor 11 is attached to the third case 74C. An adapter 15 is previously attached to the output shaft 11A of the motor 11 so as to rotate integrally with a set screw screw 16. When the adapter 15 is inserted into the cylindrical wall portion 74D of the third case 74C, the adapter 15 is fitted on the front end of the rod 14 with the flat portion 18 shown in FIG. As a result, the adapter 15 and the rod 14 can rotate together, and the output shaft 11A of the motor 11 and the rod 14 are connected so as to rotate together.

(8) The inner hub 43 of the pre-assembled viscous joint 40 is splined to the first hub 3. The rear end of the inner hub 43 abuts on the flange portion 3B of the first hub 3. Next, the bearing 64 is fitted to the drive pinion shaft 71 and fixed by the snap ring 65. Thus, the inner hub 43 and the first hub 3 are configured such that the rear side surface of the inner ring of the bearing 8 abuts on the stepped portion of the outer peripheral surface of the drive pinion shaft 71 and the front side surface of the inner ring of the bearing 64 contacts the snap ring 65. By being in contact with each other, the drive pinion shaft 71 is attached so as to be rotatable relative to the drive pinion shaft 71 and not movable in the direction of the rotation axis O1.
(9) A predetermined amount of lubricating oil is filled in the bottoms of the case rear portions 74Ba of the first case 74A and the second case 74B, and the assembly of the power transmission device 1 is completed.

The preferred embodiments of the present invention have been described above. Although the described embodiment is applied to a final reduction gear, the present invention can also be applied to, for example, a four-wheel drive auxiliary transmission. A four-wheel drive vehicle equipped with this auxiliary transmission is a four-wheel drive vehicle based on a front-wheel drive vehicle. The auxiliary transmission device is a device that is connected to a transaxle (transmission) (not shown) and distributes power to output the power output to drive the front wheels to the rear wheels.
In addition, various design changes can be made to the present invention without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Power transmission device 2 Power interruption device 3 1st hub 4 2nd hub 9 Switching sleeve 10 Switching sleeve moving mechanism 11 Motor 12 Fork 13 Feed screw mechanism 40 Viscous joint 42 Outer case 43 Inner hub 70 Final reduction device 71 Drive pinion shaft 72 Drive pinion gear 73 Ring gear 80 Differential gear P1 Cutting position P2 Connection position

Claims (6)

A viscous coupling is interposed between the propeller shaft and the drive pinion shaft, and a power interrupting device that transmits and disconnects power between the viscous coupling and the drive pinion shaft is interposed,
The viscous coupling is a power transmission device configured to include an outer case and an inner hub that form a working chamber for viscous fluid,
The drive pinion shaft and the viscous joint are arranged so as to be coaxial and overlap in the axial direction,
The power interrupting device includes a first hub that rotates integrally with the inner hub, a second hub that rotates integrally with the drive pinion shaft and intermittently connects to the first hub, and the first hub and the second hub. And a switching sleeve that intermittently
When the first hub and the second hub are connected by the switching sleeve, the inner hub and the drive pinion shaft rotate integrally,
When the first hub and the second hub are cut by the switching sleeve, the inner hub and the drive pinion shaft are cut off .   2. The power transmission device according to claim 1, wherein the drive pinion shaft is inserted through the inner hub, and a periphery of a tip of the drive pinion shaft is supported by the inner hub via a shield bearing.   3. The power transmission device according to claim 1, wherein the first hub is spline-coupled to the inner hub and supported by the drive pinion shaft via a shield bearing.   The power transmission device according to any one of claims 1 to 3, wherein the outer case is disposed outside a case containing the power interrupting device and the drive pinion shaft.   5. The power transmission device according to claim 1, wherein the drive pinion shaft is a drive pinion shaft of a final reduction gear.   5. The power according to claim 1, wherein the drive pinion shaft is a drive pinion shaft of a four-wheel drive auxiliary transmission that distributes power to a front wheel and a rear wheel. Transmission device.

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