JPH032755Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is a differential device for a part-time four-wheel drive vehicle that can switch between two-wheel drive and four-wheel drive, especially when the vehicle is in two-wheel drive. This invention relates to a differential device on the slave drive side, which is the non-drive side.

(Prior Art) Part-time four-wheel drive vehicles are switched between two-wheel drive and four-wheel drive by operating a so-called transfer device, which is a drive switching device for two wheels and four wheels. During two-wheel drive, the non-drive side (referring to the power transmission system from the drive switching device for two and four wheels to the driven wheels) is affected by the rotation of the wheels due to driving. As a result, the vehicle is driven in the opposite direction to the drive direction during four-wheel drive. The drive resistance generated by driving in the opposite direction affects vehicle vibration, noise, fuel consumption, etc., so as a countermeasure, it is necessary to partially disconnect the slave drive side power transmission system during two-wheel drive. Therefore, a freewheel hub mechanism has been considered to reduce the driving resistance as much as possible.

Conventionally, one of the freewheel hub mechanisms is equipped with a remote locking hub that divides one of the left and right axle shafts in the slave drive side power transmission system and connects and disconnects the divided shafts to each other using a remote mechanism. There is something. When driving two wheels, the remote locking hub is disconnected to leave one wheel in a free state, and the differential gear of the differential device on the slave drive side is actively differentially operated, thereby locking the differential case. is made non-rotating, thereby reducing the drive resistance of the power transmission system that extends from the ring gear of the case to the drive switching device through the drive pinion gear.

(Problem to be solved by the invention) However, in the above-mentioned conventional technology, since the differential gear of the differential device is made to perform active differential action, the rotation of the differential gear There was a problem in that the sliding resistance and the agitation resistance of the differential oil were large, and as a result, a satisfactory effect (particularly a significant improvement in fuel efficiency) could not be expected. Further, it is necessary to take more consideration than usual differential devices to prevent seizure, wear, etc. due to sliding of the differential gear.

It is also conceivable to divide the left and right axle shafts in the slave drive side power transmission system and install a remote locking hub for each axle shaft, but this would make the remote mechanism complicated. , not practical.

Furthermore, the above-mentioned conventional differential device equipped with a freewheel hub mechanism using a remote locking hub does not have a differential locking mechanism, so it has poor driving performance on rough roads such as mountain roads and rocky roads. I was dissatisfied.

(Means for Solving the Problems) This invention aims to solve the problems in the conventional technology described above.
It is a double case consisting of an inner differential case on the pinion shaft side and an outer differential case on the ring gear side, which surrounds the inner differential case and is arranged so as to be rotatable relative to each other, and between the inner differential case and outer differential case there is a lock hub. The gist of the configuration is that a tarpaulin mechanism is provided, and a differential clutch mechanism is provided between the differential case and the axle shaft.

(Function) According to the above means, when the lock hub clutch mechanism is connected, the inner differential case and the outer differential case are integrally connected, so that the driving force from the engine side is transmitted to the left and right axle shafts. , the vehicle is in four-wheel drive mode.

When the lock hub clutch mechanism is disengaged during two-wheel drive, the inner differential case can rotate relative to the outer differential case, thereby transmitting power from the ring gear of the outer differential case to the drive switching device through the drive pinion gear. System drive resistance is reduced and differential gear (side gear and pinion gear)
The agitation resistance of the differential oil due to this is almost eliminated.

Further, when the differential clutch mechanism is connected during the four-wheel drive mode, the axle shaft and the differential case are integrally connected, thereby locking the differential.

(Example) An example of this invention will be described below with reference to the drawings. FIG. 1 shows a cross section of a differential device on the slave drive side of a part-time four-wheel drive vehicle when the vehicle is running in four-wheel drive.

The differential case 1 is a double case including an inner differential case 1a and an outer differential case 1b. Inside the inner differential case 1a are a pinion shaft 2 installed therein, and pinion gears 3, 3 rotatably disposed on the shaft 2.
and side gears 4, 4 that mesh with the gears 3, 3 and are spline-fitted to opposing ends of left and right axle shafts 5, 5, respectively. The axle shafts 5, 5 project laterally through the left and right hub portions 6, 7 of the inner differential case 1a, and left and right wheels (not shown) are mounted on the tips of the axle shafts 5, 5, respectively. be done.

The outer differential case 1b is formed to surround the inner differential case 1a.
It is provided so as to be rotatable relative to the inner differential case 1a via ball bearings 8, 8 disposed on both hub portions 6, 7. The left and right hub portions 9, 10 of the outer differential case 1b are rotatably supported by a differential carrier 12 via tapered roller bearings 11, 11. The outer differential case 1b has a two-part structure in which left and right halves are connected to each other.

A drive pinion gear 15 is meshed with a ring gear 14 fixed to the outer differential case 1b with a connecting bolt 13. As is well known, the drive pinion gear 15 is rotatably supported by the differential carrier 12 and is linked to the output section of the engine via a power transmission system (not shown). The power transmission system is provided with a two-wheel and four-wheel drive switching device, and selection between two-wheel drive and four-wheel drive is made by switching the drive switching device.

A lock hub clutch mechanism C is provided between the inner differential case 1a and the outer differential case 1b.
1 is provided. This clutch mechanism C1 is
A hub sleeve 16 is disposed on the outer periphery of the left hub portion 6 of the inner differential case 1a so as to be movable in the axial direction by spline fitting, and a lock hub cylinder 17 is disposed on the differential carrier 12. A shift fork 19 fixed to the telescopic rod 18 is engaged with an annular groove 20 on the outer periphery of the hub sleeve 16 so as to be relatively rotatable.

As the hub sleeve 16 is moved to the right in the figure by the extension of the lock hub cylinder 17, the dog clutch teeth 21 of the hub sleeve 16 engage with the dog clutch teeth 22 of the left hub portion 9 of the outer differential case 1b. The inner differential case 1a and the outer differential case 1b are combined (connected) together, and the hub sleeve 16 is moved to the left in the figure by the shortening operation of the lock hub cylinder 17, so that the dog clutch teeth 21 , 21 are released (separated), and the inner differential case 1a and the outer differential case 1b are made relatively rotatable (see FIG. 2).

That is, the lock hub clutch mechanism C1 is appropriately engaged and engaged as the hub sleeve 16 moves due to the operation of the lock hub cylinder 17.

A differential clutch mechanism C2 located to the left of the lock hub clutch mechanism C1 is provided between the left axle shaft 5 and the inner differential case 1a. This clutch mechanism C
2, a hub sleeve 23 is disposed on the left axle shaft 5 so as to be movable in the axial direction by spline fitting, and a differential cylinder 24 is disposed on the differential carrier 12 to the left of the lock hub cylinder 17. A shift fork 26 fixed to a telescopic rod 25 of the cylinder 24 is engaged with an annular groove 27 on the outer periphery of the hub sleeve 23 so as to be relatively rotatable.

Then, as the hub sleeve 23 is moved to the right in the drawing by the expansion operation of the differential cylinder 24, the spline internal teeth 28 at the right end of the hub sleeve 23 are moved to the inner differential case 1a, as shown in FIG. The axle shaft 5 is meshed with (connected to) the spline external teeth 6a of the hub portion 6 of the
and the inner differential case 1a are integrally coupled, and the hub sleeve 23 is moved to the left in the figure by the contraction operation of the differential cylinder 24, so that the inner teeth 28 of both splines are connected to each other as shown in FIG. The meshing between the outer teeth 6a and the outer teeth 6a is released (separated), and the axle shaft 5 and the inner differential case 1a are made relatively rotatable.

In other words, the differential clutch mechanism C2 is appropriately engaged and engaged as the hub sleeve 23 moves due to the operation of the differential cylinder 24.

Therefore, the spline external teeth 6a of the hub portion 6 of the inner differential case 1a are shared with the hub sleeve 16 of the lock hub clutch mechanism C1 to which the hub sleeve 16 of the lock hub clutch mechanism C1 is spline-fitted. is in the disengaged position (left position in the figure), the hub sleeve 16 engages the differential clutch mechanism C2.
The hub sleeve 23 is set to be kept in the disconnected position (see Figure 2), and the locking of the differential during two-wheel drive is prevented. The disadvantages of differential locks on good roads (for example, poor steering wheel operability) are eliminated.

The operation of the lock hub cylinder 17 and the differential lock cylinder 24 is switched by a remote mechanism (not shown) connected to an appropriate operation button or lever located near the driver's seat of the vehicle. It is something that is done.

In a part-time four-wheel drive vehicle equipped with the differential device described above, when the drive switching device is operated to switch to four-wheel drive, the lock hub clutch mechanism C1 is connected as shown in Figure 1. The inner differential case 1a and the outer differential case 1b are integrally connected via the hub sleeve 16. In this state, the driving force transmitted from the engine to the drive pinion gear 15 is transmitted from the ring gear 14 to the differential case 1 (outer differential case 1b, hub sleeve 16, inner differential case 1a), pinion shaft 2, pinion gears 3, 3, and side gears. 4, 4 will be transmitted sequentially to the left and right axle shafts 5, 5,
This achieves four-wheel drive driving. In addition,
During the normal four-wheel drive described above, the differential clutch mechanism C2 is in a disengaged state.

If the drive switching device is operated to change to two-wheel drive from the above-mentioned four-wheel drive state, two-wheel drive driving is achieved by cutting off the power transmission system on the slave drive side from the engine side. . During this two-wheel drive, the power transmission system is driven in the opposite direction to the drive direction by the rotational force from the left and right wheels through each axle shaft 5, 5 toward the drive switching device. The clutch mechanism C1 is separated to allow the inner differential case 1a and the outer differential case 1b to rotate relative to each other (see FIG. 2).

As a result, the driving force transmitted from the left and right wheels to each axle shaft 5, 5 is transmitted to each side gear 4, 4, so that the inner differential case 1a is rotated relative to the outer differential case 1b. However, differential gears (side gears 4, 4 and pinion gears 3, 3) do not provide differential movement. Therefore, the drive resistance of the power transmission system from the ring gear 14 of the outer differential case 1b through the drive pinion gear 15 to the drive switching device is reduced.

Also, since the differential gear hardly moves,
The sliding resistance caused by the differential of the differential gears (side gear and pinion gear) and the agitation resistance of the differential oil, which conventionally occur, will not occur.
Note that the rotation of the inner differential case 1a only causes rolling resistance of the ball bearings 8, 8 and slight stirring resistance of the differential oil in the outer differential case 1b.
The resistance related to the rotation of the inner differential case 1a can be said to be extremely small compared to the sliding resistance caused by the differential of the differential gear and the agitation resistance of the differential oil, which have conventionally occurred. Furthermore, compared to the conventional method, there is no need to worry about seizure, wear, etc. caused by sliding of the differential gear.

In addition, if you want to lock the differential in the four-wheel drive state described above on rough roads such as mountain roads or rocky roads, connect the differential clutch mechanism C2 and move the axle shaft 5 and inner differential case 1a.
(See Figure 3). This locks the differential. Therefore, the driving performance on the rough road is improved.

Note that it is also possible to employ a solenoid, a combination mechanism of a link mechanism and a motor, etc. in place of the lock hub cylinder 17 and the differential lock cylinder 24 in the above-described embodiment. Further, the differential clutch mechanism C2 can also be disposed between the inner differential case 1a and the right axle shaft 5, or between the outer differential case 1b and either one of the axle shafts 5.

(Effects of the invention) In other words, the gist of this invention is the configuration described in the column of "Means for solving the problems" mentioned above, and when the lock hub clutch mechanism is disengaged during two-wheel drive, the inner Since the differential case can rotate relative to the outer differential case, the drive resistance of the slave drive side power transmission system from the ring gear of the outer differential case to the drive switching device through the drive pinion gear is reduced, and the differential gear (side gear and pinion gear)
Since the agitation resistance of differential oil due to
This has the effect of significantly improving fuel efficiency. Furthermore, consideration for seizure, wear, etc. due to sliding of the differential gear, which was required in the past, is no longer necessary. In addition, since it can be operated by a single remote mechanism, the operation and the structure related to the operation can be simplified, which is suitable for practical use.

Furthermore, when the differential clutch mechanism is engaged during four-wheel drive, the axle shaft and differential case are integrally connected, so that the differential is locked.
This has the effect of providing good drivability on rough roads such as mountain roads and rocky roads.

[Brief explanation of drawings]

The drawing shows one embodiment of this invention.
The figure is a cross-sectional view of the differential device on the slave drive side of a part-time four-wheel drive vehicle in four-wheel drive mode, and Figure 2 is a cross-sectional view of the same differential device in two-wheel drive mode. 3 are cross-sectional views showing the differential device in a four-wheel drive state with the differential locked. 1...Differential case, 1a...Inner differential case, 1b...Outer differential case, 2
... Pinion shaft, 5 ... Axle shaft, 14 ... Link gear, C1 ... Clutch mechanism for lock hub, C2 ... Clutch mechanism for differential lock.

Claims (1)

[Scope of utility model registration request] The differential case on the slave drive side of a part-time four-wheel drive vehicle is composed of an inner differential case on the pinion shaft side and an outer differential case on the ring gear side that surrounds the inner differential case and is arranged to be rotatable relative to each other. It has a double case, and a lock hub clutch mechanism is placed between the inner differential case and outer differential case, and a differential clutch mechanism is placed between the differential case and the axle shaft. differential device.