JPS5913394Y2 - Secondary 2-axis balancer drive mechanism - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a drive mechanism (gear train) for a secondary two-shaft balancer for an internal combustion engine.

In conventional balancer devices, the distance between the centers of the drive shaft and the balancer shaft is long, so an idle gear or a transmission gear is required in the middle, resulting in a complicated structure.

This invention mainly takes advantage of the 2-throw crank,
A large-diameter drive gear is provided on the web of the crankshaft, and a compact secondary two-shaft balancer device is placed below the crankshaft, so that the idle gear can be omitted.This will be explained next with reference to the drawings.

The crankshaft 1 in Fig. 1 is supported at three points by main bearings 2 at both ends (one of which is not shown) and a main bearing 3 in the center. There are three crank parts (throws), and FIG. 1 shows the crank throws of the parts corresponding to the first cylinder (center line 01) and the second cylinder (center line 02).

4 and 5 are connecting rods for the first cylinder and the second cylinder, respectively.

The main bearings 2, 3 are both supported by the crankcase 6 and fixed thereto by bolts 7.8.

A flywheel 10 is fixed to the right end of the crankshaft 1 by a plurality of bolts 9.

11 is a cover, 12 is a bolt for fixing the cover, and 13 is an oil seal.

In the space 15 below the crankshaft 1 between the first and second cylinders and between the third and fourth cylinders (not shown), there is a secondary space parallel to the center line O of the crankshaft 1, respectively. A two-shaft balancer 16 is arranged, and the input balancer shaft 17 of each balancer 16 is provided with an input gear 18 on the crankshaft end side, and the input gear 18 is connected to the crank web 19 of the crankshaft 1.
It meshes with a ring-shaped drive gear 20 fixed to.

The angular position of the drive gear 20 with respect to the crank web 19 is fixed by meshing and shrink-fitting a notch 21 provided on the inner periphery with a radial positioning pin 22 on the crank web 19 side.

The input gear 18 has its angular position fixed with respect to the balancer shaft 17 by a key 23, and is
The meshing position with the drive gear 20 is kept constant by alignment marks (not shown) or the like.

24 is a nut for fixing the input gear, and 25 is a balance way integrated with the balancer shaft 17.

Each balancer 16 has another driven balancer shaft 1 driven by an input gear 18 parallel to the input balancer shaft 17.
7' (FIG. 2), these include a top-opening container-shaped bearing body 27 and a bearing cap 28.28°28', 2B'.
The input gear 18 is rotatably supported by a split bearing cap type bearing consisting of a rolling bearing 29, and the input gear 18 meshes with a gear 18' having the same number of teeth fixed to the other balancer shaft 17'.

The bearing body 27 is fastened to the lower surface of the crankcase 6 with bolts 31 using four brackets 30 provided at the lower end.

32 in Figure 1 is a spacer, 33.34 is a rolling bearing 29
35. 36 is a bolt for fixing the presser plate, 37 is an oil pan fixed to the lower side of the crankcase 6, and 38 is a bolt for fixing the oil pan.

Input balancer shaft 17 and the other driven balancer shaft 17'
Center line 03. O'3 is input balancer shaft 17 side is Ll
This causes gear 1 to be higher than
8' and the drive gear 20 are prevented from meshing with each other.

The upper surface 40.40' of the bearing body 27 is located at the center line 03.40' of the balancer shaft 17°17'. It is formed of two horizontal planes including O'3, and a bearing cap 28.28 of the same shape is placed above it.
' are tightened with two bolts 41, respectively.

Instead of having the upper surface 40.40' stepped, an inclined common surface 42 is provided which includes the center lines 03, 03' of both balancer shafts 17.17', and the bearing cap 28.28' is placed on the common surface 4.
It can also be modified to suit 2.

In that case, machining of the bearing body 27 becomes easier.

When the common surface 42 is adopted, the center line of the insertion hole 43 of the bolt 41 and the screw hole 44 can be changed to be perpendicular to the surface 42 as shown in 04 in order to use the bearing cap 28, 28' as it is.

Both balancer shafts 17.17' are located at the same distance left and right from the vertical plane A including the center lines 01, 02... of each cylinder as shown in Fig. 2, and the balance weights on both balancer shafts 17.17' 25 have the same vertical phase, that is, when one balance weight 25 is at the top dead center, the other balance weight is also at the top dead center, and when one balance weight 25 is at the bottom dead center, the other balance weight 25 is at the bottom dead center. The meshing positions of both gears 18 and 18' are set so that the gears 18 and 18' are at the bottom dead center.

In addition, the balancer 16 on the right side and the balancer (not shown) on the left side of the main bearing 3 in FIG. The position, size, phase, etc. of the weights are determined.

During engine operation, the secondary two-shaft balancer 16 on both sides of the main bearing 30
are operated by receiving rotational force from the crankshaft 1, respectively, and perform a couple removal function.

That is, the rotation of the crankshaft 1 is transmitted from the drive gear 20 fixed to the crank web 19 to the input balancer shaft 17 via the input gear 18, and the input balancer shaft 17 rotates at 10 times the speed of the crankshaft, and the other balancer shaft 17' rotates at a constant speed in the opposite direction to the balancer shaft 17.

Balance way I/2 on both balancer shafts 17 and 17'
5 rotates so that the upper and lower phases are equal.

The balancer 16 can be preassembled using the bearing body 27 and the tooth caps 28, 28' to form a unit at a separate location away from the engine assembly line.
When assembling, insert the balancer unit into the space 15 below the crankshaft through the opening at the lower end of the crankcase,
With the manual gear 18 meshed with the drive gear 20, the four brackets 30 are each tightened to the crankcase 6 with bolts 31, and then the oil pan 37 is attached.As explained above, according to the present invention, A large diameter drive gear 20 is fixed to the crank web 19 of the 2-throw crank,
A secondary two-shaft balancer 16 is installed in the space 15 below the crankshaft.
is arranged parallel to the crankshaft 1, and one balancer shaft 1
A manual gear 18 having a number of teeth of 200 is fixed to the drive gear 7, and the manual gear 18 is directly meshed with the drive gear 20.
The input gear 18 is meshed with a gear 18' having the same number of teeth on the other balancer shaft 7' which is slightly biased downward so as not to mesh with the drive gear 20, and both balancer shafts 17.17
' are placed equidistant left and right from the vertical plane A that includes the center line O and 02 of each cylinder, so it is possible to eliminate the idle gear, and the overall height is significantly shortened, resulting in a compact and low-cost two-shaft system. A balancer device can be obtained.

Moreover, since the amount of downward deviation of the gear 18' is extremely small, it hardly affects the function as a secondary two-axis balancer.

Furthermore, since the balancer shafts 17 and 17' are located at equal distances from the surface A on the left and right sides, there is no possibility of generation of a couple, and the balancer function is excellent.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view, and FIG. 2 is a sectional view including a vertical section of each main part perpendicular to the crankshaft. 1... Crankshaft, 15... Space, 16... Secondary two-axis balancer, 17.17'... Balancer shaft, 1
B, 18'... Gear, 19... Crank web, 20... Drive gear

Claims (1)

[Scope of utility model registration request] A ring-shaped drive gear 20 is fixed to the crank web 19 of the crankshaft 1, a secondary two-shaft balancer 16 is arranged parallel to the crankshaft 1 in the space 15 below the crankshaft, and one balancer shaft 17 is connected to the The input gear 18 of the drive gear 20 has a fixed number of teeth, and the input gear 18 is directly meshed with the drive gear 20, and the input gear 18 is slightly biased downward so as not to mesh with the drive gear 20. It meshes with the gear 18' with the same number of teeth on the balancer shaft 7', and both balancer shafts 17°17' are arranged at equal distances left and right from the vertical plane A that includes the center line 01,0□ of each cylinder. Features a secondary 2-axis balancer drive mechanism.