JPS60104812A - Crankshaft - Google Patents

Abstract

PURPOSE:To realize the weight reduction and higher efficiency of a crankshaft by making the sectional area of the crank-pin-boss-side part of a ring-like portion smaller than that of the crank-weight-side part thereof, while said ring-like portion being used for connecting the crank pin boss to the crank weight part. CONSTITUTION:In a crank web 2, the parts contributing not so much to ensure crank balance, moment of inertia and strength are cut off to make through holes 6, thereby reducing the entire weight of the crankshaft. The crank web 2 consists of a crank weight part, a crank arm part 8 and a ring-like part 9. Those sectional areas are varied by making the thickness (t) of the ring-like part 9 constant and gradually reducing the height of the side face from the vicinity of the crank weight part 5 toward the vicinity of the crank pin boss 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The crankshaft of a reciprocating internal combustion engine usually consists of a main shaft, a constant crank pin that is eccentric with the main shaft VC ZJ, and a crank arm that connects the main shaft and the crank pin. The large end of the connecting rod is fitted through a bearing. In order to balance the lower inertia caused by the large end of the connecting rod, rotating parts such as the crank pin and crank arm, and reciprocating parts such as the piston and piston pin, a crank weight is provided on the opposite side of the crank pin with respect to the main shaft. ing.

In relatively small internal combustion engines such as motorcycle engines, a crankshaft is often used in which the crank arm and crank weight are integrated into a disc-shaped crank web with the center of the main shaft roughly centered. be done. 1st
The figure shows an example of a rank axis. This crank @OL is divided into fixed parts, each having a rear crank web 02 and 03.
, 03 is installed, and the crank bin 05Y is enlarged to the crank bin boss o4 to form one crank @lIO■.
It is a TDL vertical type crankshaft. crank web o2,
Round shape as shown in 03, main N 061.06
Regarding No. 2, a crank weight 07 is provided on the opposite side from the No. 1 crank bin boss 04. With the 08 & eco-connecting rod, the crank bin 05 [is fitted] before the crank bin 05 CV is press-fitted. 09 is a main bearing, and 01.0 is a main shaft provided on the main shaft 06.

This (1) crank @01 is crank web 02.03
Since the outer shape is circular, each MIS can be rolled and transported during manufacturing and assembly, and the round shape is relatively simple, making it easy to process and have good productivity.

The aim of the invention is to provide a crankshaft that has been improved in this way, and is even lighter in weight and has improved material efficiency while retaining its advantages and advantages.

The embodiments shown in FIGS. 2 to 4 will be described below. These drawings are shown in FIG.
When applied to such an assembled crankshaft, the crank 1li111 portion, that is, the crank web 02 and the main @06. FIG. 2 is a perspective view, a front view, and a side sectional view showing a portion 7 corresponding to the above. The other crank web facing this, that is, the crank web corresponding to crank web 03Vc in FIG. 1, also has a shape similar to that shown in FIGS. 2 to 4.

Main spindle, 2&': c, crank web, approximately disk-shaped chair centered on the axis 10 of the main spindle 1, attached to the crankshaft nib 2. A crank bottle bonnu 3 is formed on the upper part of the crank web 2 (the upper part in the drawings, the same applies hereinafter), and a crank bottle (not shown or not shown) is press-fitted into the boss hole 4 of the crank web 2. Lower part of Klantau nib 2, i.e. @ at 1
0 With respect to vc, there is a thick crank weight part 5 on the opposite side of the trunk hub boss 3, and when the crankshaft σ is rotated, the large end of the connecting rod σ is
f11s Crankbin and crankbin boss 3 vicinity σ] The rotation of the mass balances the inertial force due to the reciprocating motion of the piston, piston pin, etc. 6. 6 is a through hole provided on both sides of the upper left stone of the crank web 2, each starting from the left side or right side of the crank bin boss 3σ, and extending approximately along the contour of the crank web 2. It extends in a 71-shape to the vicinity of the crank weight portion 5. The through hole 6.6 is connected to the boss hole 4 as shown in the figure.
U) The center and the center of the main shaft 1] Each through hole is arranged symmetrically with respect to the line VC connecting it to 0, and each through hole 6σ) A section B defined by a section A and an outer section of the crank bin boss 3
60 parts that form the outer part of the boss of the main shaft 1, I'b% that connects the B part and C lake S'Y, and the through hole 6 ends near the upper end of the crank weight part 5σ. - It is formed with the B part (LS).

Therefore, if you change the point of view and look at the temperature, it will be difficult to see the crank web 2.
are the arcuate crank weight portion 5, the main shaft l1ll line 10 (/J circumference σ), the main shaft boss portion 7, the crank arm portion 8 that connects with the crank bin boss 3, and the crank bin boss 3 and the crank weight portion 5. It is composed of a ring-shaped part 9 that connects the left and right upper ends with a ring-shaped VC.Then, 2 tons are attached to the crank weight part, crank arm part and ring-shaped part, and a crankshaft 1 is required. functions are carried out most efficiently.

The crank weight part 5 is similar to a conventional crankshaft,
The most suitable position and shape for inertial lower balance are determined.

The crank arm part 8 defined by the BjJ5, B part and 0 part of the through hole 6 has a crank bin boss outer diameter d that is strong enough to press the crank bin into the crank bin and the main shaft boss part 7. Dimension e7 with sufficient strength to withstand the bending moment due to the applied explosive load and inertial load.
Moreover, there are no extra parts 2 or 1 other than the parts necessary for the press-fitting and load transmission. 'f, ta, ring-shaped part 9
VC is provided at the most efficient position for increasing the moment of inertia of the crank web 2, that is, at the outer periphery VC. In an engine, the moment of inertia of the crankshaft plays an important role in the stability of idling operation and the smoothing of torque fluctuations. It is possible to reduce the amount of electricity compared to a crankshaft with a crank weight and maintain a sufficient moment of inertia. Also, due to the existence of the annular portion 9, the outer shape of the crank web 2 is circular, as shown in FIG. Can be transported.

Furthermore, the through hole 6 is defined by a line MM on the diameter of the crank web 2 in a direction perpendicular to the diameter passing through the center 2 of the crank bin boss hole 4.
It extends further downwards, and there is a lightening τ that has a low contribution rate to the balance of inertial force.

In this way, in the uninvented crank web 2, the parts that have a low contribution to maintaining crank balance, moment of inertia, and strength "t +7m" are made into through holes 6, and the whole is made lighter, and the crank weight part 5, the crank It consists of an arm part 8, a ring part 9, and 3 pin parts.

The structure of these parts is such that they can most efficiently function as a crankshaft, but in addition, the ring-shaped parts 9 are designed to be more lightweight and efficient. There are seven diagrams.

The annular portion 9 has a W6 portion close to the sled crank bin boss 3 whose cross-sectional area is smaller than the cross-sectional area of the portion near the crank weight portion 5. In the illustrated embodiment, the thickness t (FIG. 3) of the annular portion 9 is uniform and the side height H
(, 5j, Figures -2 and 4) are gradually lowered from the vicinity of the crank weight component 5 to the vicinity of the crank bin boss, thereby changing the cross-sectional area. 91.92.9*0 Consisting of three parts, height H of item 91, close to taranta weight part 5vc
The height 11 of the part 93 near the crank bin boss 3 is lowered, and the inclined part 9 between these two parts 91.93 is relatively high. Nyo T! There is more to come.

Item 9I is close to the MM line (FIG. 2) K, and the quality M of this portion is small enough to lower the crank balance rate. Therefore, the measured surface height H is increased and the mass is made thicker in the portion 9I of the C portion, which is useful for increasing the moment of inertia of the crank web 2.
It is located in a fixed position away from Mi toward the crank bin, and the degree to which it reduces the crank balance rate is large. Therefore, τ of this portion 9 has a lower height H, and τ has a much smaller mass. However, since the outermost circumference of the crank web 2 is located at the outermost periphery of the crank web 2, the moment of inertia of the web 2 increases by 7°C.
There is. And these items 97.93, the middle part 9. height H changes gradually. By connecting the annular portion 9 with the force 5, the moment of inertia of the crank web 2 can be efficiently maintained without affecting the thickness of the crank web 2. The thickness is uniform throughout the entire Hz@-shaped portion 9, and the thickness is the same as that of the t-shaped portion 9. Thick at 93Vc, thin again, G and VC? It is also possible to change the lj-order ratio. In this case, the ring-shaped part 9 rig I shape is made into a smooth circular shape, and the thickness is changed by 10,000 mm, so that the through hole 6 is formed in the contour part AVC.

In non-embodiments or in addition, the crank weight portion 5
A recess 11 is provided at the upper center of the axis near 10vC.
A7:). This component has a low contribution rate in terms of strength and a low contribution rate to the crank bimbo VC, and also has a small influence on the moment of inertia VC. Therefore, this part has been thinned out and the overall weight has been reduced.

As mentioned above, the uninvention is the disc-shaped crank web'! a
A crank having l' [tqHVc, the crank weight part, crank arm part, and ring-shaped part σ are provided as through holes in the parts of the crank web that have a low contribution rate in establishing the crank balance, moment of inertia, and strength Z) It has a structure consisting of three parts, so that these parts can perform the function as a crankshaft most efficiently,
Moreover, the part σJ near the crank bin boss for the ring shape mi
By making the area smaller than the cross-sectional area of the part near the crank weight part, further weight reduction and efficiency have been achieved. Therefore, to the uninvented crankshaft,
Conventional σ is much more WFI JR than σ, the material cost is lower, and since the crank web has a circular Z shape, it is easy to withdraw during manufacturing and assembly, and productivity is high.

In addition, regardless of whether the engine is noble or inventive, there are many.

Needless to say, it can also be applied to the crank @tfc of a cylinder engine.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a conventional crankshaft 7 - Fig. 2 is a perspective view showing an embodiment of the invention, Fig. 3 is a front view of the same, and Fig. 4 is a sectional view of the same side. , 2... Crank web, 3... Crank hinge boss, 4... Boss hole, 5... Crank weight part, 6... Through hole, 7... Spindle boss part, 8...
°・Crank arm part, 9...ring-shaped part, ]0...
・Axis of main shaft, 11°°. recess. Agent: Patent attorney Nozomi Ehara (2 persons) Figure 1 Figure 2 Figure 3 - No. 8

Claims (1)

[Claims] There is no disc-shaped z centered on the ITIII line of the main axis,
The crankshaft has a crankbin boss and a tarunk web having an arcuate part and a crank weight diametrically opposed to the crankbin. It is composed of a crank arm portion that connects with a crank bin boss, and a ring-shaped portion that connects the crank bin boss and the left and right upper ends of the crank weight portion in a ring shape, and the ring-shaped portion is close to the crank bin boss. A crankshaft characterized in that the cross-sectional area of the portion is smaller than the cross-sectional area of the portion near the crank weight portion.