JPH0135087Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to the improvement of differential gears used in automobiles and the like.

[Prior Art] In a differential device used to smooth drive rotation by absorbing differential rotation between left and right wheels, front and rear wheels, etc. of automobiles, etc., the entire or a part of the differential case is sealed, There is also one in which lubricating oil is sealed inside, and the oil bath lubricates each sliding part such as the internal differential gear, the shaft, or the friction plate of the friction clutch as an internal slip limiting mechanism by splashing lubrication. in this case,
The temperature of the lubricating oil rises due to agitation due to the rotation of the internal rotating member or sliding of the friction plates, causing volume expansion. In order to absorb this expansion, the sealed portion is not completely filled with lubricating oil, usually leaving about 20% space or air space. In this state, the lubrication and the absorption of the expansion caused by the rise in temperature of the lubricating oil can be carried out satisfactorily, but on the other hand, disadvantages arise due to the presence of the air layer. That is, there is a phenomenon in which oxygen in the air gradually oxidizes and deteriorates the lubricating oil as it reacts with the lubricating oil that has been vigorously stirred and heated.

Therefore, the lubrication performance may deteriorate and the durability of the device may be impaired.

[Purpose of the invention] An object of the present invention is to provide a differential device that can prevent oil oxidation and extend its life, and can also absorb expansion caused by the rise in temperature of filled oil.

[Structure of the invention] In order to achieve the above object, the invention provides a differential device having a differential case with at least a portion of the differential case having a sealed portion, and a differential gear that is filled in the sealed portion of the differential case to lubricate the sliding portion. The lubricating oil has a structure that includes a lubricating oil, and an expansion absorbing means that can absorb the expansion of the lubricating oil due to a rise in temperature without contacting the air.

[Example] Hereinafter, an example of this invention will be described in detail with reference to FIGS. 1 and 2.

In the case of FIG. 1, a differential case 3 rotatably supported by a differential carrier by a bearing (not shown) is rotated by a ring gear 5 mounted on its outer periphery being driven by a drive pinion 7. Inside the differential case 3, there is a pinion gear 11 that is rotatably fitted into the pinion shaft 9. Side gears 13a and 13b are engaged with the left and right sides of the pinion gear 11, and each output shaft 15 is connected to each side gear 13a and 13b.
a and 15b are extended. Furthermore, side gear 1
Friction clutches 17a, 17b are disposed on the left and right between the outer peripheries of the bosses 3a, 13b and the inner periphery of the differential case 3, which act as slip limiting mechanisms. In a differential device with a slip limiting mechanism configured as described above,
O-rings 19a and 19 (not shown) are provided at the penetrating portions of the pinion gear shaft 9 with the differential case 3 at both ends.
b. Oil seals 21a, 2 are installed between the outer peripheries of the bosses of the left and right side gears 13a, 13b and the differential case 3.
Oil seals 23a and 23b are provided on the inner spline portions of the left and right side gears 1b and 13b, and a sealed portion 25 is formed within the differential case 3 by these seal members. It is provided from a recess on the inner periphery of the differential case 3 in the sealed portion 25, at the bottom of the drawing, and the accumulator 27 is installed here.
is installed. The accumulator 27 is made of a stretchable material such as oil-resistant rubber and is filled with inert gas or air. In this case, the accumulator 27 is placed in a state in which there is no space within the sealed portion 25, that is, in a state in which there is no contact with air.
Acts as an expansion absorption means that absorbs by compressing and reducing the

When using a differential device with the above configuration,
The internal space of the front sealed part 25 to be assembled into the automobile is completely filled with lubricating oil so that no air remains, and the subassembly of the differential is completed. When a differential gear mechanism or a slip-limiting friction clutch 17 is operated while a car is being driven, lubricating oil generates heat and expands in volume depending on the temperature. This expansion is absorbed by the accumulator 27 as it is compressed and contracted, and the pressure inside the sealed portion 25 in the differential case 3 remains constant. Since there is no air layer within the sealed portion 25, no oxidation phenomenon occurs regardless of the temperature rise or stirring of the lubricating oil, and there is no deterioration of the lubricating oil due to oxidation. Therefore, the lubricating oil in the differential case 3 maintains an extremely long engine life, and there is no need to replace the lubricating oil in the differential case 3, which is complicated, difficult, and requires special equipment as in the past.

Note that examples of mounting positions include A, B, and C.

Note that the configurations, functions, etc. other than those described above are substantially the same as those of the previous embodiments, including this embodiment and the embodiments described later, so explanations thereof will be omitted.

Another embodiment is shown in FIG. In this case, the accumulator 27 is provided at the center of the inner end of one output shaft 15b. Unlike the previous embodiment, a piston with an O-ring is slidably provided in the circular hole at the center of the output shaft 15b, and the back of the piston is left as a space. A coil spring is installed internally as a return means. Therefore, the oil seals 23a, 23
If such a configuration is adopted, in which b is provided between the case and the output shaft, the dedicated oil-resistant rubber outer shell used in the previous example is not used, and the process can be carried out using only machining and general-purpose materials such as O-rings. It is possible and convenient.

[Effects of the invention] As explained above, according to the differential device of this invention, by providing a sealed structure and an accumulator, it is possible to absorb the expansion caused by the temperature rise of the oil filled in the differential case. This prevents damage to the differential gear, leakage, etc., while also preventing oil oxidation, avoiding oil deterioration caused by this oxidation, extending the life of the oil, and extending the life of the equipment. can.

[Brief explanation of the drawing]

1A and 1B are schematic cross-sectional views of the differential device of this invention, and FIG. 2 is a schematic cross-sectional view of another embodiment. Explanation of main drawing symbols, 3... Differential case, 2
5... sealed part, 29... expansion absorption means.

Claims (1)

[Scope of utility model registration request] A differential gear having a differential case with a sealed part, lubricating oil filled in the sealed part of the differential case to lubricate the sliding part, and expansion of the lubricating oil as the temperature rises in a non-contact state with outside air. A differential device characterized in that it is equipped with an expansion absorbing means capable of absorbing.