JPS603386Y2 - Bearing device for crankshaft of horizontally opposed engine - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a bearing device for a crankshaft of a horizontally opposed engine.

As a crankshaft bearing system, as shown in Fig. 1, a two-part bearing case 3 is assembled to the journal portion 2 of the crankshaft 1 via a flat bearing 4, and is attached to both end walls and the middle partition wall of the crankshaft. There is a so-called tunnel method in which the bearing case 3 is fitted and fixed into a crankshaft insertion hole that is arranged in a tunnel-like manner.

In this bearing system, the completely semicircular lower case 3a is positioned on the bottom dead center side so that it can sufficiently absorb the explosion pressure.

However, if the above bearing structure is applied as is to a horizontally opposed engine, the explosion pressure will also act on the case 3b, which has a smaller pressure-receiving area, resulting in a problem of reduced durability of the bearing case 3 and the crankcase.

The purpose of this idea was to solve the above-mentioned problems in horizontally opposed engines in which the crankshaft is supported by a tunnel method, and for this purpose, the bearing case, which is divided into two parts, was made point-symmetrical with the center of the bearing as the center of symmetry. form,
The feature is that the dividing plane is vertically positioned.

Examples of this invention will be described below based on the drawings.

FIG. 2 is a cross-sectional view of the forced air-cooled horizontally opposed engine, and FIG. 3 is a front view of the crankshaft bearing device.

In the figure, the engine has cylinders 12R and 12L protruding horizontally from the front right side wall and rear left side wall of the crankcase 11, respectively, a crankshaft 13 arranged in the center of the crankcase 11, and a flyhorn fan at the front end. 14
A crank gear 15 is attached to each rear end.

The above-mentioned crankshaft 13 is connected to the rear wall 1 of the crankcase 11.
It is assembled into the case from the 1c side, and the three journal parts 16 are supported by the front wall 11a, intermediate wall 11b, and rear wall 11c of the crankcase 11 via bearings, respectively.

Among them, the journal portion 16 at the front end is supported by the front wall 11a via a two-piece flat bearing 17, and both journal portions 16 at the intermediate and rear ends are supported by the intermediate journal portion 16 through a bearing unit B shown in FIG. It is supported by the wall 11b and the rear wall 11C.

Bearing unit B consists of a semicircular bearing case 18 that is divided into left and right halves, which are integrated into a ring shape with two bolts 19, and a two-part flat bearing 17 is fitted into a bearing mounting hole 20 on the inner circumference of the bearing case 18. Intricately composed.

Both of the bearing cases 18 mentioned above are formed symmetrically with the bearing center as the center of symmetry, and a bolt tightening seat 22 is formed by cutting out the circumferential surface near one end of the bearing case 18, and a dividing surface P is formed from this.
A bolt insertion hole 23 is provided therethrough, and a screw hole 24 is formed in the dividing surface P near the other end.

The bearing unit B configured in this manner has the crankshaft 13
It is assembled in advance to the journal part 16 of the crankshaft 13.
It is incorporated into the crankcase 11 together with the intermediate wall 11.
It is fitted into a crankshaft insertion hole 21 provided through the rear wall 11c and the rear wall 11c.

Then, with the dividing plane P vertical, the bearing case 18 is fixed to the intermediate wall 11b and the rear wall 11c with bolts (not shown) or the like.

The diameter of the crankshaft insertion hole 21 is set to be slightly larger than the longest dimension of the crank arm.

According to the above configuration, the explosion pressure acting in opposite left and right directions can be equally received by both bearing cases 18 having the same pressure receiving area, and its durability can be improved.

Furthermore, since both cases 18 are symmetrical, only one mold, processing jig, processing machine, etc. need be prepared, and in combination with the dual use of parts, the manufacturing cost of the bearing unit can be significantly reduced.

4A and 4B show different embodiments, and in A, the center axis of the bolt 19 is inclined with respect to the dividing plane P, so that the notch of the bearing case 18 is shifted toward the end, and the load is concentrated. In addition, B allows the bearing case 18 to be separated from the dividing surface P.
This embodiment differs from the above embodiments in that both cases 18 are formed line-symmetrically with respect to the center of symmetry, and both cases 18 are fixed with bolts 19 and triangular nuts 25.

As explained above, in this invention, the crankshaft is supported by a tunnel bearing structure, and the bearing case is divided into two parts, which are formed in a point-symmetrical shape with the center of the bearing as the center of symmetry. Since the acting explosive force is evenly received by the bearing cases with the same pressure receiving area, the loads on the left and right sides due to the explosive movement force of the left and right pistons are distributed between the left and right bearing cases and the case. The pressure is applied evenly to each contact surface with the support wall, lowering the surface pressure than if it were applied unevenly, improving the durability of the contact surface, and distributing the explosive force equally to each adjacent bearing case. This can be transmitted to the crankcase to suppress the amount of vibration and noise generated.

Furthermore, since both bearing cases are symmetrical, the bearing device can be manufactured at low cost by using common parts.

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional bearing unit, Figures 2 to 4 are
Figures A and B show examples of this invention, Figure 2 is a cross-sectional view of the engine, Figure 3 is a front view of the bearing device, Figure 4 is A,
B is a front view showing another embodiment of the bearing device. 11...Crank case, 13...Crankshaft, 16...Journal part, 17...
...Flat bearing, 18...Bearing case, 2
1... Crankshaft insertion hole, P... Division surface, B... Bearing unit.

Claims (1)

[Claims for Utility Model Registration] 1. The journal portion 16 of the crankshaft 13 is supported by the bisected bearing case 18 via the bisected flat bearing 17, and inserted into the crankshaft insertion hole 21 formed in the crankcase 11. In the horizontally opposed engine in which the above-mentioned bearing cases 18 are fitted and fixed, both bearing cases 18 are formed in a point-symmetrical shape with the bearing center as the center of symmetry, and the dividing plane P thereof is positioned vertically. Bearing device for the crankshaft of the opposed engine. 2. In the bearing device for a crankshaft of a horizontally opposed engine according to Claim 1 of the Utility Model Registration Claim, one end of the peripheral surface of each bearing case 18 is cut out to form a bolt tightening seat 2.
2, and a port 19 is screwed from each tightening seat 22 to the mating bearing case 1B.