JPS6218788Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a breather device as a ventilation device for a case body that houses a power transmission mechanism such as a transmission or a speed reducer.

Generally, in a case body such as a transmission case that incorporates a power transmission mechanism, it is necessary to provide a ventilation device for lubricating oil filled in the case body, that is, a breather device. However, in the past, this type of breather device had a breather device consisting of a valve body etc. attached to the case body, so a breather device separate from the case body had to be prepared, and the breather device was attached to the case body. The breather device must be installed in a protruding manner, which increases the number of parts and, if the installation space of the case body is narrow, the protruding breather device may interfere with other objects, which is undesirable. . Therefore, in cases where the case body is formed by combining opposing cases,
Some attempts have been made to form a breather device using the fixing bolts that fix the cases together and their through holes, but in this case, the breather device still protrudes from the case body because the fixing bolts pass through them. and, moreover,
The through hole leading to the outside air communicates with the inside of the case body through a communication hole, but unlike the case where the through hole is drilled from the outside of the case, this communication hole is connected to the inside of the case. A new drawback arises in that the hole must be drilled so that it communicates with the through hole, which requires a special drilling technique.

The present invention was devised in order to eliminate these drawbacks in view of the above-mentioned actual situation, and utilizes a case positioning knock pin that does not protrude from the case body and its fitting hole. The object of the present invention is to provide a breather device that can be constructed without any protrusion from the case, and that can communicate the fitting hole and the inside of the case without using special drilling techniques. In particular, the cases facing each other are configured to be positionable via knock pins that fit into fitting holes drilled in the thick portions of the case mating surfaces, and grooves or grooves are formed on the outer periphery of the knock pins in the length direction. A gap is formed between the dowel pin and the fitting hole by forming a notch in the flat part, and the gap is carved in the mating surface of the case to communicate with the inner communication groove leading to the inside of the case and the outside air. It is characterized in that it communicates with an outer communicating hole located deep within the matching hole.

The structure of the present invention will be explained with reference to one embodiment shown in the drawings. 1 is an engine of an agricultural tractor;
The transmission is comprised of a front wheel drive section 3 and a rear wheel drive section (not shown). 4 is a propeller shaft that transmits power from the front wheel drive power extraction section 3 to the front wheel drive section 5, and 6 is a front wheel. 7 is a front wheel drive shaft supported by bearings 8 and 9, 10 is bearing 1
1 and 12, the bearings 9 and 11 are connected to the first case 12, and the bearings 8 and 12 are connected to the first case 12.
is assembled to a second case 14 which is joined and fixed to the first case 13, and by interposing a dowel pin 15 between the two cases 13 and 14, the bearings 8 and 9 and between the bearings 11 and 12 are connected to each other. This allows positioning to be performed while maintaining accuracy. Fitting holes 18 and 19 for the knock pins 15 are provided in the thick parts of the mating surfaces 16 and 17 of both cases 13 and 14.
are bored, but the fitting holes 18, 1 of this embodiment
9 is formed by reaming a previously drilled pre-drilled hole to match the dowel pin fitting depth; The pre-machined holes serve as decompression chambers 25 and 26.

On the other hand, the opening edges of the fitting holes 18 and 19, which become the mating surfaces 16 and 17 of the cases, are chamfered 22 and 23, and when the cases 13 and 14 are fixed together, the chamfers 22 and 23 are Communication grooves 20 and 21 carved in case mating surfaces 16 and 17
In this embodiment, the communication grooves 20, 21 and the chamfers 22, 23 constitute an inner communication hole that communicates with a cavity 37, which will be described later. In addition, the decompression chamber 25,
26 is a ventilation hole 29 bored in the cases 13 and 14;
It is in communication with the outside air via 30.

The knock pin 15 has a cylindrical shape, and a groove or flat portion 31 is cut out on its circumferential surface over the entire length in the longitudinal direction. A gap 37 is formed between them. This cavity 37 communicates with the inner communication hole as described above, and also communicates with the decompression chambers 25 and 26.
6 and communication holes 29 and 30. A gasket 24 seals between the mating surfaces 16 and 17.

32 is a drive gear assembled to the front wheel drive shaft 7, 33 is a final reduction gear assembled to the front wheel shaft 10, and the front wheel drive shaft 7 and the front wheel shaft 10 are interlocked via these gears 32 and 33. There is. 34
35 is the oil contained in the case, 35 is an oil seal that seals the penetration part between the front wheel drive shaft 7 and the first case 13, and 36 is oil that seals the penetration part between the front wheel drive shaft 10 and the second case 14. It's a sticker.

Next, the operation of the present invention constructed as described above will be explained. Power from the engine 1 is transmitted to a front wheel drive shaft 7 via a transmission 2 and a propeller shaft 4. The power transmitted to the front wheel drive shaft 7 is transmitted through the gear 3
2 and 33 to the front wheel axle 10, causing the front wheel 6 to rotate. At this time, as the gears 32 and 33 rotate, the oil 34 is stirred and the oil temperature rises, causing the pressure inside the case to rise. In this case, the air inside the case is transferred to the first and second cases 13,
Communication groove 2 formed on mating surfaces 16 and 17 of 14
0, 21, through the chamfered portions 22, 23, through the gap portion 37 formed by the flat portion 31 of the dowel pin and the inner peripheral surface of the fitting holes 18, 19, and then through the communicating hole 29,
Decompression chambers 25, 26 communicate with outside air via 30
Since the air in the case flows into the decompression chambers 25 and 26 through the gap 37, it flows out into the outside air through the ventilation holes 29 and 30.

By the way, when the air inside the case flows out, decompression chambers 25 and 26 are formed at the inner end of the fitting holes 18 and 19 on the back side of the end surface of the knock pin 15.
is formed, and the decompression chambers 25 and 26 are
As a result of reaming the pre-machined hole, a step is formed between the knock pin fitting part and both ends of the cavity 37 are narrowed by this step, so that the gap 37 is connected to the decompression chamber. The mixture of air and oil that has flowed into the vacuum chambers 25 and 26 is
Gas and liquid are separated within 5 and 26, and only air flows out from vent holes 29 and 30.

In this way, the inside of the case is communicated with the outside air and a breather action is performed. Since the breather device is formed using the dowel pins 15 that fit into the fitting holes 18 and 19, the breather device does not protrude from the cases 13 and 14, and even if the case body has a narrow installation space, the breather device will not get in the way. It's not going to happen at all.

Moreover, the gap 37 provided between the knock pin 15 and the fitting holes 18 and 19 can be formed by simply cutting out the circumferential surface of the knock pin 15.
In addition, the inner communication hole that communicates the cavity 37 with the inside of the case does not need to be drilled only on the inside of the case using a special drilling technique, and the chamfers 22 and 22 are formed on the mating surfaces 16 and 17 of the case, which are easy to process. 23 and the communication grooves 20, 21, it can be formed by assembling the case body, simplifying the work of forming the breather device.

Note that when the pressure inside the case decreases, outside air flows into the case following the opposite route to that described above. Therefore, in order to remove dust floating in the outside air, it is necessary, for example, to install an air cleaner at the opening ends of the ventilation passages 29 and 30, or to fill the decompression chambers 25 and 26 with air cleaner elements. is desirable. Also, the dowel pin fitting hole 18,1
9, the decompression chambers 25 and 26 are in communication with the outside air, so when the dowel pin is inserted and the case is fitted together, the air is not compressed in the fitting hole and the dowel pin insertion becomes extremely difficult, unlike in the conventional case, and the cases can be assembled easily. It becomes extremely easy.

In the above embodiment, the ventilation area is secured by providing communication grooves and chamfers on the mating surfaces of both cases, but even if the communication grooves and chamfers are provided on only one mating surface, the communication grooves cannot be removed by the knock pins. or the flat part 3 of the dowel pin.
It goes without saying that the intended purpose can also be achieved by making the groove 1 face the communicating groove and omitting the chamfering.

In short, the present invention is configured such that the cases facing each other can be positioned via knock pins that fit into fitting holes drilled in the thick parts of the case mating surfaces, and the two cases are arranged longitudinally on the outer periphery of the knock pins. A gap is formed between the dowel pin and the fitting hole by cutting out a groove or a flat surface, and the gap is cut into the mating surface of the case to connect an inner communication groove leading to the inside of the case and the outside air. Since the fitting hole communicates with the outer communicating hole at the back of the case, it is possible to use the fitting hole drilled in the thick part of the case mating surface and the positioning dowel pin that fits into the fitting hole. The breather device can be formed without protruding from the outer surface of the case, and even if the case body has a narrow installation space, the breather device will not get in the way. Moreover, in order to communicate the breather device from the inside of the case to the gap formed between the fitting hole and the knock pin, there is no need to perform a special drilling operation on the case itself to communicate with the gap formed between the fitting hole and the knock pin.
Communication is possible by carving an inner communication groove on the case mating surface that is easy to process and fitting the cases together.
The work of forming the inner communication hole that communicates from the inside of the case to the cavity becomes easy, and as a result, a breather device using a dowel pin and its fitting hole can be easily formed without using special drilling techniques. It is possible.

[Brief explanation of the drawing]

The drawings show an embodiment of the breather device according to the present invention, in which FIG. 1 is an overall side view of an agricultural tractor equipped with the present invention, and FIG.
Line sectional view, Figure 3 is a sectional view of the main part of Figure 2, Figure 4 is a sectional view of the main part of Figure 2.
The figures are a sectional view taken along the line -- in FIG. 3, FIG. 5 is a perspective view of the dowel pin, and FIG. 6 is an enlarged sectional view of a part of FIG. 3. In the figure, 13 and 14 are a case, 15 is a knock pin, 16 and 17 are mating surfaces, 18 and 19 are fitting holes,
20, 21 are communicating grooves, 22, 23 are chamfers, 2
5 and 26 are decompression chambers, 29 and 30 are ventilation holes, and 37 is a cavity.

Claims (1)

[Claims for Utility Model Registration] (1) Cases facing each other are configured to be positionable via knock pins that fit into fitting holes drilled in the thick parts of the case mating surfaces, and the outer periphery of the knock pins A groove or a flat part is cut out in the length direction to form a gap between the knock pin and the fitting hole, and the gap is
A breather device characterized in that an inner communication groove carved on a mating surface of a case and communicating with the inside of the case communicates with an outer communication hole deep inside a fitting hole that communicates with outside air. (2) The outer communication hole is composed of a decompression chamber formed by a pre-machined hole for the fitting hole on the back side of the end of the dowel pin fitted into the fitting hole, and a vent hole that communicates with the outside air from the decompression chamber. A breather device according to claim 1 of the utility model registration claim.