JPH0737977Y2 - All-wheel drive for rear engine bus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a rear engine bus in which the output of an engine arranged at the rear of a bus is transmitted to a final reduction gear for front wheels and rear wheels via a transmission. The present invention relates to an all-wheel drive device, and more particularly to a support structure for a planetary gear type differential gear device.

<Prior Art> As an all-wheel drive device for a truck or the like, a power distribution device is provided between a final reduction gear device connected to front wheels and a drive shaft and a final reduction gear device also connected to rear wheels and a drive shaft. There is one in which a transfer is provided and the output of the engine is transmitted to each of the front wheel and rear wheel final reduction gears via the transmission and the transfer.

However, in such a conventional all-wheel drive device, since the transfer is arranged between the two wheels, the floor of the vehicle is inevitably raised. Therefore, the above-mentioned all-wheel drive device cannot be applied to a bus in which the height of the floor cannot be made too high due to restrictions such as getting on and off.

On the other hand, as shown in FIG. 2, the one that drives a plurality of drive shafts at the same time has been conventionally known (Shokaisho 58).
-97346 and Japanese Utility Model Laid-Open No. 59-176227).

This is a front diff gear 13 and a rear diff gear 14 of the same specifications that mesh with a pinion gear 12 driven by an output shaft 7a of a transmission, and one drive shaft
Divider gear 16 connected to final reduction gear 15 driving 10
On the other hand, the front shaft 13 is spline-coupled to the front differential gear 13 while the through shaft 18 is connected to the final reduction gear device 17 for driving the other drive shaft 11.

However, when this is applied to a so-called rear engine bus in which an engine is arranged at the rear of the vehicle, even though the front shaft and the rear shaft share different axial loads, the distribution is made via the differential gears 13 and 14. Since the transmitted torques are equal, there arises a problem that proper all-wheel drive cannot be performed according to the sharing of the axial load.

Therefore, the present applicant previously proposed an all-wheel drive device for a rear engine bus that can distribute the engine output torque to the front wheels and the rear wheels according to the axial load sharing while suppressing the rise of the floor surface of the vehicle. (See Japanese Utility Model Application No. 62-40971).

This is a differential gear consisting of a ring gear and a sun gear that are concentrically arranged, and a pinion gear that is provided in an interaxle differential case that is driven by the output shaft of the transmission and that rotationally drives the ring gear and the sun gear around the axis. A device is provided, the ring gear is connected to the final reduction gear for rear wheels, and the sun gear is connected to the final reduction gear for front wheels.

<Problems to be Solved by the Invention> By the way, in the all-wheel drive system for the rear engine bus proposed by the present applicant, the interaxle differential case,
In a planetary gear type differential gear device having a pinion gear, a ring gear, and a sun gear as constituent elements, the support structure for each of these elements needs to be devised in terms of equal distribution of load, vibration, and noise.

Therefore, in view of the conventional situation, the present invention provides a planetary gear type differential gear device with an interaxle differential case,
It is an object of the present invention to improve the support structure of each component of the pinion gear, the ring gear, and the sun gear so as to realize even distribution of load and reduce vibration and noise.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a ring gear and a differential gear device composed of a sun gear and a pinion gear arranged concentrically, and a divider gear connected to the ring gear. The pinion gears are rotatably attached to the interaxle differential case fixed to the tip of the input shaft connected to the output shaft of the transmission via the pinion shafts, respectively, and the divider gear is configured to drive the rear drive shaft. A front wheel end gear that meshes with a pinion drive gear that is connected to a pinion shaft of a rear wheel drive pinion that meshes with a drive gear in a wheel final reduction gear, and the sun gear has a gear shaft that drives a front drive shaft via a propeller shaft. Pinion gear that forms part of the reduction gear The rear end of the interaxle differential case is supported by a front end of the divider gear via a bearing, and the front end of the interaxle differential case is supported by an interaxle differential cover covering the interaxle differential case through the bearing. The end portion of the sun gear that is opposite to the meshing end portion of the gear shaft with the pinion gear and protruding from the interaxle differential case is cantilevered via a bearing in the interaxle differential cover, the ring gear and the divider gear. Is a rear-engine bus all-wheel drive system that is spline-fitted with a specified backlash.

<Operation> In the all-wheel drive system for the rear engine bus configured as described above, the engine torque drives the interaxle differential case via the transmission, and the interaxle differential case drives the pinion gear. The pinion gear drives a ring gear and a sun gear that mesh with the pinion gear. At this time, the torque is distributed to the sun gear and the ring gear by the ratio of the distance between the rotation center of the output shaft of the transmission and the meshing point of the sun gear and the pinion gear and the distance between the rotation center and the meshing point of the pinion gear and the ring gear.

The torque transmitted to the ring gear is transmitted to the ring gear via the divider gear pinion drive gear and the rear wheel drive pinion, and the rear wheel is driven by decelerating and converting the rotation direction.

The torque transmitted to the sun gear is transmitted to the front wheel final reduction gear transmission to drive the front wheels.

Then, in the planetary gear type differential gear device, the ring gear and the sun gear move to positions where the loads applied from the pinion gears become equal, and the loads can be evenly distributed.

When the inter-axle differential case is made by casting or forging, for example, it has a large rotational imbalance and becomes a source of vibration and noise. However, since both ends of the inter-axle differential case are supported by bearings, this problem does not occur.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a power distribution device 20 that distributes the output torque of an engine arranged at the rear of the bus to two shafts arranged substantially coaxially with an output shaft of a transmission (not shown).
Is provided in front of a rear wheel final reduction gear transmission 22 that transmits power to the rear wheel drive shaft 21, and one shaft of the power distribution device 20 is connected to the rear wheel final reduction gear transmission 22. In addition to being connected, the other shaft of the power distribution device 20 is connected to a front wheel final reduction gear transmission that transmits power to a drive shaft of front wheels (not shown).

Here, the power distribution device 20 and the rear wheel final reduction gear device 22
Is constituted by a tandem type speed reducer in which these are contained in a housing composed of an axle housing 23, a carrier 24 and a carrier cover 25.

The power distribution device 20 includes a differential gear device 29 including a ring gear 26 and a sun gear 27, which are concentrically arranged, and a plurality (for example, three) of pinion gears 28, and a ring gear 26 via a ring gear plate 30. Articulated divider gear
31 and.

The pinion gears 28 are rotatably attached to the interaxle differential case 33 fixed to the tip of the input shaft 32 connected to the output shaft of the transmission via the pinion shafts 34, respectively.

The divider gear 31 meshes with a pinion drive gear 37 that is connected to a pinion shaft 36a of a rear wheel drive pinion 36 that meshes with a drive gear 35 of the rear wheel final reduction gear transmission 22.

The gear shaft 27a of the sun gear 27 is connected to a pinion gear that constitutes a part of a front wheel final reduction gear drive that drives a front wheel drive shaft via a propeller shaft (not shown).

Further, a sliding type diff lock clutch 38 is provided which connects the divider gear 31 and the input shaft 32 freely in a disengageable manner.

Here, the rear end of the interaxle differential case 33 is a rear bearing 39 as a bearing at the front end of the divider gear 31.
The front end portion of the interaxle differential case 33 is supported by the interaxle differential cover 41 via a front bearing 40 as a bearing. The end of the sun gear 27 opposite to the meshing end of the gear shaft 27a with the pinion gear 28 and protruding from the interaxle differential case is attached to the interaxle differential cover 41 via a bearing 42 as a bearing. Has been supported. On the other hand, the ring gear 26 and the divider gear 31 are spline-fitted with a predetermined backlash.

In this case, the spline 30a, 30b is formed on the inner and outer peripheral surfaces of the ring gear plate 30, and the outer spline 30a is formed.
Is a spline formed on the inner peripheral surface of the end of the ring gear 26,
The inner peripheral side splines 30b are fitted to the splines formed on the outer peripheral surface of the front end portion of the divider gear 31, respectively.

It should be noted that either the inner or outer spline fitting structure may be adopted. In this case, the divider gear 31 and the ring gear plate 30 are integrally formed, or the ring gear plate 30 and the ring gear 26 are integrally formed. .

In such a configuration, the engine torque drives the input shaft 32 and the interaxle differential case 33 via the transmission, and the interaxle differential case 3
3. Drive the pinion gear 28 via the pinion shaft 34. The pinion gear 28 drives a ring gear 26 and a sun gear 27 that mesh with the pinion gear 28. At this time, the engine torque is
The ratio between the rotation center of the input shaft 32 and the meshing point of the sun gear 27 and the pinion gear 28 and the distance between the rotation center of the input shaft 32 and the meshing point of the pinion gear 28 and the ring gear 26 is distributed to the sun gear 27 and the ring gear 26. It

The torque transmitted to the ring gear 26 is transmitted to the drive pinion 36 via the ring gear plate 30, the divider gear 31, and the pinion drive gear 37. Drive pinion
Reference numeral 36 meshes with the drive gear 35, where deceleration and rotation direction conversion are performed, and the rear wheels are driven via an axle shaft (not shown).

On the other hand, the torque transmitted to the sun gear 27 is transmitted to the front wheels via the propeller shaft and the rear wheel final reduction gear transmission.

As described above, since the transfer is not used, it is possible to prevent the floor surface of the vehicle from rising, and it is possible to maintain the floor height advantageous for getting on and off the vehicle.

Further, the transmission torque transmitted to the front wheels via the ring gear 26 is larger than the transmission torque transmitted to the rear wheels via the sun gear 27 due to the radius ratio of the ring gear 26 and the sun gear 27.

Therefore, in the rear engine bus in which the engine is arranged at the rear of the bus, even if the axial load of the rear wheels is larger than the axial load of the front wheels, the transmission torque is distributed according to the axial load sharing.

According to this structure, the sun gear 27 and the pinion gear 28 are supported by cantilever supporting the protruding end portion of the gear shaft 27a of the sun gear 27 from the interaxle differential case 33 on the interaxle differential cover 41 via the bearing 42.
The ring gear 26 is allowed to move within a predetermined range in the radial direction by allowing the meshing part of the ring gear 26 and the divider gear 31 to be spline-fitted with a predetermined backlash while allowing the meshing part to move in the predetermined range in the radial direction. Since it is movable, the sun gear 27 and the ring gear 26 are floating elements among the components of the planetary gear type differential gear device, and the sun gear 27 and the ring gear 26 receive the load applied from the plurality of pinion gears 28. Move to equal position,
The load is evenly distributed.

On the other hand, the interaxle diff case 33 has a large rotational imbalance because it is made by casting or forging, and if it is used as a floating element, it becomes a source of vibration and noise. Since the part is supported by the divider gear 31 and the interaxle differential cover 41 via bearings 39 and 40 to be a fixed element, vibration and noise of the interaxle differential case 33 can be prevented.

In the present embodiment, the differential gear device 29 of the power distribution device 20 is arranged in front of the rear wheel final reduction gear device 22, but the present invention is applied to a device arranged behind the rear wheel final reduction gear device. You may apply.

<Effects of the Invention> As described above, according to the all-wheel drive system for a rear engine bus of the present invention, the ring gear and the sun gear are supported so as to be movable in a predetermined range in the radial direction. By moving to a position where the loads applied from the pinion gears are equal, it is possible to evenly distribute the loads.

Also, when the interaxle differential case is made by casting or forging, for example, the rotational imbalance is large and it becomes a source of vibration and noise, but since both ends of the interaxle differential case are supported by bearings, vibration prevention Aim for
This is a great practical effect for achieving low noise.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an all-wheel drive system for a rear engine bus according to the present invention, and FIG. 2 is a sectional view of a conventional all-wheel drive system. 22 ... Rear wheel final reduction gear, 26 ... Ring gear, 27 ... Sun gear, 27a ... Gear shaft, 28 ... Pinion gear, 29 ... Differential gear unit, 30 ... Ring gear plate, 30a, 30b ... Spline, 31 ... Divider gear, 32 ... Input shaft, 33
… Interaxle differential case, 34… pinion shaft,
36 ... rear wheel tribe pinion, 37 ... pinion drive gear, 39 ... rear bearing, 40 ... front bearing, 41
… Interaxle differential cover, 42… Bearing

Claims (1)

[Scope of utility model registration request] 1. A differential gear device comprising a ring gear, a sun gear, and a pinion gear arranged concentrically, and a divider gear connected to the ring gear, wherein the pinion gear is connected to an output shaft of a transmission. Each of which is rotatably attached to an interaxle diff case fixed to the tip through a pinion shaft, and the divider gear is a rear wheel drive pinion that meshes with a drive gear in a rear wheel final reduction gear that drives a rear wheel drive shaft. It meshes with a pinion drive gear connected to a pinion shaft, the gear shaft of the sun gear is connected to a pinion gear that forms a part of a front wheel final reduction gear drive that drives a front wheel drive shaft via a propeller shaft, and the interaxle The rear end of the differential case is A front end portion of the divider gear is supported via a bearing, and a front end portion of the interaxle differential case is supported via a bearing on an interaxle differential cover covering the interaxle differential case, and a meshing end of the sun gear gear shaft with the pinion gear is supported. The end opposite to the part that protrudes from the interaxle diff case is cantilevered on the interaxle diff cover via a bearing, and the ring gear and the divider gear are spline fitted with a predetermined backlash. The all-wheel drive system for the characteristic rear engine bus.