JP2004017734A - Tandem type differential device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the weight of an entire device, relatively easy to assemble, and relatively easy to make shim adjustment in a helical gear. <P>SOLUTION: A power transfer 21 is built in an inter-differential incorporating 20a. A transfer case 20b for housing the helical gear 23 and a counter gear 27 fixed on a drive pinion shaft 26a and meshed with the helical gear 23 is provided on a rear part of the inter-differential housing 20a. A carrier case 20c for pivotally supporting a ring gear 28 for meshing with a drive pinion 26 is provided on a rear part of the transfer case 20b. A front part of the helical gear 23 is rotatably supported through a bearing 32 fixed by a bearing cage 33. The bearing cage 33 is mounted on the inter-differential housing 20a, and the transfer case 20b and the carrier case 20c are integrally formed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tandem-type differential device having a built-in power distributor for distributing the rotational power of a propeller shaft to the rear rear shaft and the rear front shaft.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a tandem differential device for a rear two-axle vehicle, a tandem type differential device provided with a power distributor for distributing rotational power of a propeller shaft to rotational power of a rear rear shaft and a rear front shaft is known. As shown in FIG. 5, this conventional tandem-type differential device is a power distributor that distributes the rotational power of a propeller shaft 1 to the rotational power of a rear rear shaft drive shaft 3 extending in the front-rear direction and the rotational power of a helical gear 4. 5, a transfer case 2b containing a helical gear 4 and a counter gear 6 fixed to the drive pinion shaft 5a and meshing with the helical gear 4 is provided at the rear of the inter differential housing 2a. A carrier case 2c pivotally supporting a ring gear meshing with the gear 5 is provided at the rear of the transfer case 2b. Here, the inter differential housing 2a, the transfer case 2b, and the carrier case 2c are independently formed, the transfer case 2b is screwed to the rear of the inter differential housing 2a, and the carrier case 2c is screwed to the rear of the transfer case 2b. Is done. The rear front shaft is attached to the ring gear, and the ring gear and the drive pinion 5 constitute a final reduction gear. The rear rear axle (not shown) is rotated by the rotation of the rear rear axle drive axle, so that the rear two-axle runs.
[0003]
On the other hand, since a relatively large driving force is applied to the helical gear 4, both sides of the helical gear 4 are pivotally supported by a pair of conical roller bearings 8a and 8b. The part is rotatably supported. Here, in the conventional device, the bearing cage 9 is screwed to the transfer case 2b. Here, since the pair of bearings 8a and 8b used are of a conical roller type, the dimension between the pair of bearings 8a and 8b is adjusted when the bearing cage 9 is screwed. This is performed by interposing a shim having a predetermined thickness between the transfer case 9 and the transfer case 2b. By adjusting the dimension between the pair of bearings 8a and 8b in this manner, the rotation resistance of the helical gear 4 is optimized.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional tandem type differential device, it is necessary to manufacture the inter differential housing 2a, the transfer case 2b, and the carrier case 2c independently of each other, and to attach and integrate them to each other, to form the respective cases 2a, 2b, 2c. Since there are a plurality of attachment parts, the weight of the entire apparatus increases due to the presence of the fastening flanges for fastening them, and the number of man-hours for fastening them also increases, thereby increasing the unit price of the entire apparatus. Was.
In the shim adjustment in the conventional tandem-type differential device, a shim having a predetermined thickness is interposed between the bearing cage 9 and the transfer case 2b, and the bearing cage 9 is once attached. Is measured. For this reason, once the bearing cage 9 is removed and replaced with a shim initially interposed, the shim must be replaced by a relatively thick shim when the resistance value is high, and by a relatively thin shim when the resistance value is low. In order to obtain the optimum rotational resistance of the helical gear 4, this operation needs to be repeated about two or three times, and the adjustment operation is relatively complicated.
SUMMARY OF THE INVENTION An object of the present invention is to provide a tandem type differential device which can reduce the weight of the entire device and can be relatively easily assembled.
Another object of the present invention is to provide a tandem-type differential device that can relatively easily adjust shims in a helical gear.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, as shown in FIG. 1, the power distributor 21 that distributes the rotational power of the propeller shaft 13 to the rotational power of the rear rear drive shaft 22 extending in the front-rear direction and the rotational power of the helical gear 23 is provided. A transfer case 20b built in the inter differential housing 20a and containing a helical gear 23 and a counter gear 27 fixed to the drive pinion shaft 26a and meshing with the helical gear 23 is provided at the rear of the inter differential housing 20a. A tandem differential device in which a carrier case 20c pivotally supporting the meshing ring gear 28 is provided at the rear of the transfer case 20b, and the front of the helical gear 23 is rotatably supported via a bearing 32 fixed by a bearing cage 33. It is an improvement of.
The characteristic configuration is that the bearing cage 33 is attached to the inter differential housing 20a, and the transfer case 20b and the carrier case 20c are integrally formed.
[0006]
In the tandem differential device according to the first aspect, since the transfer case 20b and the carrier case 20c are integrated, it is possible to assemble the work by simply fastening the transfer case 20b and the transfer case 20b. For this reason, the number of fastening members such as bolts required for fastening can be reduced as compared with the related art, and a relatively thick fastening flange portion required for fastening is not required, thereby reducing the weight of the entire apparatus and A relatively inexpensive device can be obtained as the number of work steps for fastening them is reduced.
[0007]
In addition, since the bearing cage 33 is attached to the inter differential housing 20a, the frontage of the front part of the transfer case 20b can be made larger than before, and the degree of freedom in design can be improved. In addition, since the bearing cage 33 is attached to the inter differential housing 20a, it can be performed by interposing a shim 37 having a predetermined thickness between the bearing cage 32 and the inter differential housing 20a. Therefore, the thickness of the shim 37 can be determined by a simple operation of merely measuring the dimension t at the step between the front end surface of the transfer case 20b and the front end surface of the bearing cage 33, and the adjustment of the rotational resistance of the helical gear is optimized. The work can be performed relatively easily.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 4, the rotational force generated by the engine 11 of the rear two-axle vehicle 10 rotates a tandem type differential device 20 that rotates a rear front shaft 14 via a transmission 12 and a propeller shaft 13 and a rear rear shaft 16. The driving force is transmitted to the rear rear shaft differential device 19, and the rear front shaft 14 and the rear rear shaft 16 rotate, so that the left and right rear front wheels 17 and the rear rear wheel 18 can rotate and travel. The propeller shaft 13 is connected to a tandem-type differential device 20, and rotational force is transmitted from the tandem-type differential device 20 to a rear-rear-shaft differential device 19 via a connection shaft 19 a. Therefore, the tandem differential device 20 is provided with a power distributor 21 (FIG. 1) that distributes the rotational power of the propeller shaft 13 to the rotational power of the rear front shaft 14 and the rear rear shaft 16.
[0009]
As shown in detail in FIG. 1, the tandem differential device 20 includes an inter differential housing 20a, a transfer case 20b, and a carrier case 20c in this order from the front, and the power distributor 21 is mounted on the frontmost inter differential housing 20a. Built-in. The power distributor 21 includes a first side gear 21a spline-fitted to a front end of a rear rear shaft drive shaft 22 having a front end connected to a front end of a connecting shaft 19a, and a helical gear 23 opposed to the first side gear 21a. And two differential pinions 21c (two of which are not shown) meshing with both the first and second side gears 21a and 21b. Is rotatably fitted to each arm of a cross-shaped spider 21d, and the spider 21d is provided on an input axle 24 connected to the propeller shaft 13. The first and second side gears 21a, 21b, the differential pinion 21c and the spider 21d constitute a power distributor 21 having a differential function. The power distributor 21 is built in an inter-def housing 20a, and the input axle 24 is connected to the inter-def housing. It is pivoted on 20a.
[0010]
The transfer case 20b includes a helical gear 23 and a counter gear 27 fixed to the drive pinion shaft 26a and meshing with the helical gear 23. The rear of the inter differential housing 20a is screwed to the transfer case 20b, and a carrier case 20c for pivotally supporting a ring gear 28 meshing with the drive pinion 26 is provided at the rear of the transfer case 20b. The rear front shaft 14 is attached to the ring gear 28, the rotational power of the propeller shaft 13 is distributed by the power distributor 21, the counter gear 27 rotates by the helical gear 23 that rotates, and the drive pinion 26 that rotates by the rotation of the counter gear 27. As a result, the ring gear 28 rotates, and the rear front shaft 14 rotates. On the other hand, the rear rear shaft drive shaft 22 is connected to the rear rear shaft differential device 19 via a connection shaft 19a, and the rear rear shaft 16 is rotated by the rotation of the rear rear shaft drive shaft 22 (FIG. 4).
[0011]
On the other hand, since a relatively large driving force is applied to the helical gear 23, both sides of the helical gear 23 are pivotally supported by a pair of conical roller type bearings 31 and 32, the rear bearing 31 is directly attached to the transfer case 20b, and the front bearing 32 is The front part of the helical gear 23 is rotatably supported by the bearing cage 33 in a fixed state. A characteristic configuration of the present invention is that the bearing cage 33 is attached to the inter differential housing 20a, and the transfer case 20b and the carrier case 20c are integrally formed. An axle housing 36 is attached to a rear portion of the carrier case 20c, and a gearbox including a ring gear 28 and a drive pinion 26 is lubricated on an inner bottom portion of the axle housing 36 when the axle housing 36 is attached to the carrier case 20c. Oil is stored.
[0012]
Next, a procedure for assembling the tandem differential device having such a configuration will be described.
As shown in FIG. 2, first, a ring gear 28 is pivotally supported on the carrier case 20c, and a drive pinion shaft 26a is pivotally supported on the transfer case 20b such that the drive pinion 26 meshes with the ring gear 28. Thereafter, the counter gear 27 is spline-fitted to the drive pinion shaft 26a and screwed, and a rear bearing 31 for pivotally supporting the rear of the helical gear 23 meshing with the counter gear 27 is attached to the transfer case 20b. Thereafter, the front bearing 32 is fitted into the front part of the helical gear 23 together with the bearing cage 33 to which the bearing 32 is fixed.
[0013]
Here, a pair of conical roller type bearings 31 and 32 used for pivotally supporting the helical gear 23 are used, and the dimension between the pair of bearings 31 and 32 is adjusted when the bearing cage 33 is screwed. There is a need. This adjustment is performed when the front bearing 32 is fitted into the front part of the helical gear 23. That is, the bearing 32 is fitted into the front portion of the helical gear 23 and the bearing cage 33 is pressed rearward. The pressing pressure P is proportional to the rotational resistance of the helical gear 23. When the optimum resistance value of the helical gear 23 is obtained, the dimension t at the step between the front end face of the transfer case 20b and the front end face of the bearing cage 33 is measured. . Here, as shown in FIG. 3, since the dimension t at the step and the rotational resistance of the helical gear 23 are proportional, the optimal dimension of the helical gear 23 is obtained by obtaining the dimension t at this step in the finally assembled state. Rotational resistance can be obtained.
[0014]
Thereafter, the front end bearing 32 together with the bearing cage 33 is once removed from the front of the helical gear 23 to prepare a shim 37 (FIG. 1) having the same thickness as the measured dimension t. The bearing cage 33 is attached to the rear end edge of the differential housing 20a with the shim 37 interposed therebetween. As shown in FIG. 1, the second side gear 21b is spline-fitted to the helical gear 23 so that the rear end of the inter differential housing 20a is in close contact with the front end of the transfer case 20b. The case 20b is screwed. Then, the bearing cage 33 attached to the rear end edge of the inter differential housing 20a enters from the front end face of the bearing cage 33 by an amount corresponding to the thickness of the shim 37 interposed therebetween, and the dimension between the pair of bearings 31 and 32. Is a value at which the optimal resistance value of the helical gear 23 is obtained, and the resistance value is optimized.
[0015]
In the tandem-type differential device having such a configuration, the transfer case 20b and the carrier case 20c are integrated, so that it is possible to assemble the work by simply fastening the transfer case 20b to the inter differential housing 20a. Therefore, compared to the conventional case where each case is manufactured independently, fastening members such as bolts required for fastening can be reduced, and the transfer case 20b and the carrier case 20c required for the fastening can be reduced. A thick fastening flange portion formed between them is not required, so that the weight of the entire apparatus can be reduced, and a relatively inexpensive apparatus can be obtained as the number of work steps for fastening them is reduced. Also, since the bearing cage 33 is attached to the inter differential housing 20a, the mounting margin conventionally required for attaching the bearing cage to the transfer case 20b becomes unnecessary, and the frontage of the front part of the transfer case 20b is compared with the conventional case. Can be larger. For this reason, it is possible to use a larger helical gear 23, and it is possible to improve the design flexibility.
[0016]
Further, since the bearing cage 33 is attached to the inter differential housing 20a, shim adjustment in the tandem differential device 20 can be performed by interposing a shim 37 having a predetermined thickness between the bearing cage 32 and the inter differential housing 20a. Will be possible. Therefore, the bearing 32 is fitted into the front portion of the helical gear 23 and the bearing cage 33 is pressed rearward, and the step between the front end surface of the transfer case 20b and the front end surface of the bearing cage 33 where the optimum resistance value of the helical gear 23 is obtained. The thickness of the shim 37 can be determined by a simple operation of merely measuring the dimension t at. Therefore, it is not necessary to mount and remove the bearing cage a plurality of times required in the conventional device until obtaining the optimal rotational resistance of the helical gear, and the adjustment operation can be performed relatively easily.
[0017]
【The invention's effect】
As described above, according to the present invention, since the transfer case and the carrier case are integrated, it is possible to assemble the work by simply fastening the transfer case to the inter differential housing. For this reason, the number of fastening members such as bolts required for fastening can be reduced as compared with the related art, and a relatively thick fastening flange portion required for fastening is not required, thereby reducing the weight of the entire apparatus and A relatively inexpensive device can be obtained as the number of work steps for fastening them is reduced.
In addition, since the bearing cage is attached to the inter differential housing, the frontage of the transfer case can be made larger than before, and the degree of freedom in design can be improved. In addition, since the bearing cage is attached to the inter differential housing, it can be performed by interposing a shim having a predetermined thickness between the bearing cage and the inter differential housing. Therefore, the thickness of the shim can be determined by a simple operation of simply measuring the dimension at the step between the front end surface of the transfer case and the front end surface of the bearing cage. This can be easily performed in comparison.
[Brief description of the drawings]
FIG. 1 is a sectional view taken along line AA of FIG. 4 showing a differential device according to an embodiment of the present invention.
FIG. 2 is an enlarged sectional view showing the assembled state.
FIG. 3 is a diagram showing the relationship between the rotational resistance of the helical gear and the thickness of the shim.
FIG. 4 is a main part configuration diagram of a rear two-axle including the device.
FIG. 5 is a sectional view corresponding to FIG. 1, showing a conventional differential device.
[Explanation of symbols]
13 Propeller shaft 20a Inter differential housing 20b Transfer case 20c Carrier case 21 Power distributor 22 Rear rear shaft drive shaft 23 Helical gear 26 Drive pinion 26a Drive pinion shaft 27 Counter gear 28 Ring gear 32 Bearing 33 Bearing cage

Claims (1)

A power distributor (21) for distributing the rotational power of the propeller shaft (13) to the rotational power of the rear rear shaft drive shaft (22) extending in the front-rear direction and the rotational power of the helical gear (23) is provided in the inter differential housing (20a). A transfer case (20b) which is built-in and incorporates the helical gear (23) and a counter gear (27) which is fixed to the drive pinion shaft (26a) and meshes with the helical gear (23) is formed by the transfer case (20b). A carrier case (20c) is provided at the rear of the transfer case (20b) and pivotally supports a ring gear (28) meshing with the drive pinion (26), and is fixed by a bearing cage (33). A tandem in which a front portion of the helical gear (23) is rotatably supported via a bearing (32). In the differential device,
Said bearing cage (33) is mounted on said inter-diff housing (20a);
A tandem-type differential device, wherein the transfer case (20b) and the carrier case (20c) are integrally formed.

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