JPH0821518A - Seal structure of transmission case - Google Patents

Abstract

PURPOSE:To improve the seal quality of a transmission case by simple processing. CONSTITUTION:In the case of a transmission case M seal structure which forms a sealed space at its inside by combining one set of division cases 1A, 1B integrally and at the same time interposing a bonding agent between the joining surfaces 1C, 1D of both, at least one side division case 1A, chamferings 3 are formed at a border angle portion between the joining surface 1C and a case inner surface 1E.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure for a mission case in which a set of divided cases are integrally combined and an adhesive is interposed between the mating surfaces of the two cases to form a sealed space inside.

[0002]

2. Description of the Related Art Generally, a mission case formed by integrally combining a pair of divided cases has a structure in which an internal lubricant oil does not leak to the outside by interposing an adhesive between the mating surfaces. .

[0003]

However, in the actual mission case, since the split cases are integrally combined with each other by using a large number of bolts and nuts for the fitting margin,
There is a risk of oil leakage or oil bleeding, if not leaking, at the portion where the nut tightening force is weak, or at the portion where the adhesive coating thickness between the mating surfaces is thin. Therefore, in order to eliminate such an inconvenience, there is also a structure in which a groove is formed on the entire circumference of the mating surfaces of the divided cases so as to increase the coating thickness of the adhesive to improve the sealing property. .
However, in this type of seal structure, since a concave groove must be formed on the entire circumference of the non-linear mating surface, it is difficult to process and requires time and effort to manufacture.

The present invention has been made by paying attention to the above circumstances, and the purpose thereof is simple processing.
An object of the present invention is to provide a mission case seal structure capable of improving the mission case sealability.

[0005]

To achieve the above object, the present invention is characterized in that a set of divided cases are integrally combined and an adhesive is interposed between the mating surfaces of the two cases to form an internal structure. It is a seal structure of a mission case that forms a closed space, and at least one of the divided cases has a chamfer formed at a boundary corner portion between a mating surface and an inner surface of the case.

[0006]

[Operation] In the state where a pair of divided cases are integrally combined,
An adhesive agent is interposed between the mating surfaces, and an adhesive agent pool is formed in the chamfered portion over the entire circumference of the mating margin. Further, since the chamfer is formed at the boundary corner between the mating surface and the inner surface of the case, it can be easily formed even if the boundary corner is non-linear.

[0007]

Therefore, the sealability of the mission case can be improved by simple processing.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 6, a mission case M having an input shaft 5 from which power is transmitted from an engine E through a belt transmission F is provided.
The traveling wheel 10 is connected to the output axle 9 of the above, and the management machine K is comprised. In this embodiment, a rotary tiller R is provided at the rear.
Are shown as an example.

As shown in FIGS. 1 and 2, the mission case M includes a pair of split cases 1A and 1B, which are mating surfaces 1C and 1C.
The adhesive 2 is interposed between D and both cases 1A, 1
B is integrally connected along the mating surfaces 1C and 1D by using bolts and nuts.

One divided case 1 of the mission case M
In A, a chamfer 3 is formed at a boundary corner between the mating surface 1C and the case inner surface 1E, and a reservoir 4 of the adhesive 2 is formed between the mating surface 1C and the other divided case 1B over the entire circumference of the fitting margin. It will be. Here, the split cases 1A and 1B are formed by die casting of aluminum, for example. Further, the chamfer 3 has a chamfering dimension of about 1 mm, so that a reliable sealing property is obtained. Further, the chamfer 3 may be formed by performing a chamfering step after casting, or may be formed by chamfering a boundary corner portion in advance at a mold stage so that the chamfer 3 is formed on a cast product. Since the dimensions are small, it is possible to form the chamfer 3 also for deburring, which is a necessary step after casting.

In the transmission case M, an input shaft 5, a back shaft 6, an auxiliary transmission shaft 7, a chain transmission shaft 8 and an axle 9 are installed between the split cases 1A and 1B.

The input shaft 5 includes a shift arm 11 for main transmission.
The main transmission gear 50 that slides to the left and right by the operation is mounted via a spline.

The back shaft 6 has a back shift arm 1
A large-diameter gear 50A of the main transmission gear 50 of the input shaft 5 and a back gear 60 which is always in mesh with the main gear 50 of the input shaft 5 are mounted via a spline while sliding left and right by the operation of 2.

A first reduction gear 70, which is a multi-stage gear, is mounted on the auxiliary transmission shaft 7 so as to be freely rotatable via a bush. Further, a fourth reduction gear 71 is attached to the auxiliary transmission shaft 7 via a bush so as to be freely rotatable. Further, the auxiliary transmission shaft 7 is engaged with the first reduction gear 70 or the fourth reduction gear 71 by the operation of the auxiliary transmission shift arm 13 so that the auxiliary transmission gear 72 is capable of shifting to high and low.
Is mounted so as to be freely rotatable and slidable via a bush.

A first reduction gear 70 is attached to the chain transmission shaft 8.
And a second reduction gear 80 that always engages, a fourth reduction gear 71 and a third reduction gear 81 that always engages, and a chain transmission gear that includes a drive sprocket 82 while being integrally rotatable via a spline. 83 is attached via a bush so as to be freely rotatable.

The axle 9 is integrally provided with a driven sprocket 90 which is idlely connected to the drive sprocket 82 of the chain transmission gear 83 via the chain 100, and transmits the power from the chain transmission gear 83 to the traveling wheels 9. It is configured.

When the main transmission gear 50 is slid to the right from the neutral position shown in FIG. 3, the small-diameter gear 50A and the large-diameter gear 70A of the first reduction gear 70 are in mesh with each other, and conversely, the sliding operation is performed from the neutral position to the left. The large diameter gear 50B and the small diameter gear 70B of the first reduction gear 70 are in an engaged state.

Accordingly, when the main transmission gear 50 is slid to the right and the sub transmission gear 72 is slid to the right, the power from the input shaft 5 causes the main transmission gear 50, the first, second, third and fourth reduction gears to move. 70, 80, 81, 71, the auxiliary transmission gear 72, and the chain transmission gear 83 are transmitted in the stated order to obtain the first forward speed.

Next, when the main transmission gear 50 is slid to the left and the sub transmission gear 72 is slid to the right, the power from the input shaft 5 is reduced by the main transmission gear 50, the first, second, third and fourth deceleration gears. The gears 70, 80, 81, 71, the auxiliary transmission gear 72, and the chain transmission gear 83 are transmitted in the stated order to obtain the second forward speed.

Next, when the main transmission gear 50 is slid to the right and the sub transmission gear 72 is slid to the left, the power from the input shaft 5 causes the main transmission gear 50, the first reduction gear 70, and the sub transmission gear 7 to move.
2, the chain transmission gears 83 are transmitted in the stated order to obtain the third forward speed.

Next, when the main transmission gear 50 is slid to the left and the sub transmission gear 72 is slid to the left, the power from the input shaft 5 causes the main transmission gear 50, the first reduction gear 70, and the sub transmission gear 7 to move.
2, the transmission gears 83 are transmitted in the stated order to obtain the fourth forward speed. When the back gear 60 is slid to the right, the small gear 60A is constantly meshed with the main transmission gear 50.
And the large diameter gear 70A of the first reduction gear 70 are in an engaged state, and when the slide operation is performed to the left, the main transmission gear 50 is constantly engaged and the large diameter gear 60B and the small diameter gear 70B of the first reduction gear 70 are in an engaged state. Become. Here, FIGS. 3 and 4 show a state in which the back gear 60 is slid to the left.

Therefore, when the aircraft is backed up,
When the back gear 60 is slid to the right and the sub transmission gear 72 is slid to the right, the power from the input shaft 5 is transferred to the main transmission gear 50,
Back gear 60, first, second, third, fourth reduction gear 7
0, 80, 81, 71, the auxiliary transmission gear 72, and the chain transmission gear 83 are transmitted in this order to obtain the first reverse speed.

Next, when the back gear 60 is slid to the left and the sub transmission gear 72 is slid to the right, the power from the input shaft 5 causes the main transmission gear 50, the back gear 60, the first, second, third, and fourth gears to move. The reduction gears 70, 80, 81, 71, the auxiliary transmission gear 72, and the chain transmission gear 83 are transmitted in the stated order to obtain the second reverse speed.

Next, when the back gear 60 is slid to the right and the sub transmission gear 72 is slid to the left, the power from the input shaft 5 causes the main transmission gear 50, the back gear 60, and the first reduction gear 7 to move.
0, the auxiliary transmission gear 72, and the chain transmission gear 83 are transmitted in this order to obtain the third reverse speed.

Next, when the back gear 60 is slid to the left and the sub transmission gear 72 is slid to the left, the power from the input shaft 5 causes the main transmission gear 50, the back gear 60, and the first reduction gear 7 to move.
0, the auxiliary transmission gear 72, and the chain transmission gear 83 are transmitted in this order to obtain the fourth reverse speed.

The first reduction gear 70 is a multi-stage gear in which a large number of teeth are integrally formed by cold forging, and a large number of gear bodies are integrally assembled by press fitting or welding to a mounting shaft body. In comparison, it has advantages such as the number of manufacturing steps, cost reduction, and improvement of finishing accuracy.

As shown in FIG. 4, one end side of the auxiliary transmission shaft 7 has a fourth reduction gear 7 spline-fitted to the auxiliary transmission shaft 7.
Since the outer peripheral portion of No. 1 is supported by the bearing 14, the auxiliary transmission shaft 7 and the fourth reduction gear 71 are sub-divided by a length corresponding to the length in which the sub-transmission shaft 7 and the fourth reduction gear 71 are overlapped with each other, as compared with an ordinary support structure in which the shaft end is directly bearing-supported. Since the length of the speed change shaft 7 can be shortened,
The width of the mission case M can be reduced by the shortened length.

As shown in FIG. 4, an oil supply hole 15 is formed in the upper part of the transmission case M, and a screw plug 16 is normally screwed into the oil supply hole 15 to close the transmission case M. Here, the oil supply hole 15 is
By forming the front end side of the effective screw portion of the screw plug 16 into the internal space, the wall thickness of the mounting portion of the screw plug 16 is made as thin as possible. Since it is not necessary to provide a thick boss-shaped mounting portion, processing is easy.

[Other Embodiments] The chamfer 3 of the split cases 1A and 1B is described as being formed on one of the split cases 1A in the above embodiment, but the chamfer 3 is formed on both split cases 1A and 1B. Even in both split cases 1A, 1B
Alternatively, the chamfers 3 may be alternately formed. The present invention can be applied not only to the mission case but also to a simple gear box or other power transmission case.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is an exploded side view showing the relationship between divided cases.

FIG. 2 is a sectional view of a main part

FIG. 3 is a cross-sectional view of the mission case as seen in the direction of the arrows in FIG.

FIG. 4 is a cross-sectional view of the mission case as seen in the direction of the arrow of FIG.

FIG. 5 is a principle diagram showing a transmission structure of a transmission case.

[Figure 6] Overall side view of the management machine

[Explanation of symbols]

 1A, 1B split case 1C, 1D mating surface 1E case inner surface 2 adhesive 3 chamfer M mission case

Claims (1)

[Claims] 1. A set of split cases (1A) and (1B) are integrally combined, and mating surfaces (1C) and (1) of the two are combined.
A seal structure of a mission case (M) in which an adhesive (2) is interposed between D) to form a closed space inside, and at least one of the divided cases (1A) has a mating surface (1
Chamfer (3) at the boundary corner between C) and the inner surface of the case (1E)
The seal structure of the mission case that has been formed.