JPH0110512Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a balancer device for a reciprocating internal combustion engine with a one-cylinder or two-cylinder 360° crank arrangement. Narai 2
The present invention relates to a balancer device for simultaneously eliminating reciprocating inertia force and rolling moment.

[Conventional technology and its issues]

Generally, for example, in a one-cylinder internal combustion engine, 1
There are reciprocating inertia forces of the second order and higher order, and this first order reciprocating inertia force can be easily canceled by a set of balancer devices, but the reciprocating inertia force of second order and higher orders is eliminated by this set of reciprocating inertia forces. The internal combustion engine is complicated because it cannot be erased by one balancer device and is erased by another set of balancer devices whose speed is twice the rotational speed of the crankshaft.

Therefore, the present inventors focused on the fact that when the crankshaft has a constant rotational speed and the balancer shaft has an arbitrary unequal rotational angular velocity, the centrifugal force of the balancer weight can be changed to an arbitrary magnitude over time.
Even with one set of balancer devices, not only the primary but also the secondary
We have proposed a balancer device that can eliminate reciprocating inertia forces or reciprocating inertia couples of: That is, 1
We proposed a balancer device in which the balancer shaft of a set of balancer devices is rotated at a non-uniform rotational angular velocity with respect to a crankshaft rotating at a constant speed by meshing non-circular gears (Utility Model Application Publication No. 77302/1983). Kosho 61
-2838) (see publication).

On the other hand, as is well known, in a reciprocating internal combustion engine with a one-cylinder or two-cylinder 360° crank arrangement, primary and secondary reciprocating inertia forces are theoretically generated due to the reciprocating linear motion of pistons, etc. However, such linear motion does not generate any other vibrations. Therefore, in such an engine, it is only necessary to eliminate these reciprocating inertia forces.

However, in general reciprocating internal combustion engines, including such engines, since the gas pressure is at its highest during the explosion process, torque fluctuations naturally occur, and this torque fluctuation causes the piston side pressure to fluctuate, which becomes a vibration originating force. A so-called rolling moment occurs. Such a rolling moment may act as a significant source of vibration depending on the usage conditions of the engine.

The primary and secondary internal combustion engines generated in such a one-cylinder or two-cylinder 360° crank arrangement reciprocating internal combustion engine
The balancer device described in the above-mentioned publication cannot eliminate both the reciprocating inertia force and the rolling moment at the same time.

[Means to solve the problem]

Therefore, the present invention aims to simplify the structure by incorporating the balancer device described in the above-mentioned publication into a reciprocating internal combustion engine with a one- or two-cylinder 360° crank arrangement, and also to eliminate the rolling moment at the same time. It was devised to simultaneously achieve these objectives, and its gist is that a pair of balance weights that rotate in opposite directions are used to eliminate the reciprocating inertia of an internal combustion engine, relative to the axial direction of the piston. One or two cylinders are arranged on both sides and at different distances from the center of the crankshaft on the side opposite to the piston, and the rotation of the crankshaft is linked to the shaft for the balancer weight by changing the angular velocity. It is found in the balancer device of an internal combustion engine with a cylinder 360° crank arrangement.

〔Example〕

The structure and operation of the present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

Although the reciprocating internal combustion engine in the figure shows a one-cylinder engine,
is a crankshaft, 2a and 2b are balancer shafts provided separately from this, and 3a and 3b are balancer shafts 2a and 2b, respectively.
The balance weight attached to 2b is shown.

Reference numeral 4 denotes a drive gear attached to the crankshaft 1, and its structure is approximately elliptical, as will be explained later. 5 is one balancer shaft 2a
The driven gear is attached to the drive gear 4, and its structure, as explained later, has an approximate elliptical shape and meshes with the drive gear 4. In addition, the balancer weights 3a, 3b are connected to the balancer shafts 2a, 2b.
This allows them to rotate in opposite directions at the same speed. Note that 7 indicates the rotation circle of the crank pin.

[Elimination of primary and secondary or higher order reciprocating inertia forces] Now, the reciprocating inertia force F _H of the engine caused by the reciprocating motion of the piston 6 etc. is expressed by the following equation.

F _H = W _H /g・R・ω _A ²・{cos(β+θA)+Q ₂
cos2 (β+θ _A )}...(1) Where, W _H : Weight of reciprocating part R : Crank radius ω _A : Angular velocity of crankshaft 1 θ _A : Rotation angle of crankshaft 1 Q ₂ : Constant determined by the crankshaft It is expressed as Q ₂ =1/λ, λ=L/R.

L: Length of the connecting rod β: Angle determined by the crankshaft g: Acceleration of weight In the above equation, higher-order inertial forces of the fourth order or higher are omitted.

Further, the inertia force F _B in the piston axis, that is, the x-axis direction, due to the balance weights 3a and 3b is expressed by the following equation.

F _B =2W _B /g・R _B・ω _B ²・sinθ _B …(2) Here, ω _B : Angular velocity of balancer shafts 2a, 2b W _B : Balancer weight 3a or 3b1
Unbalanced weight per piece R _B : Rotation radius of balancer weight 3a θ _B : Rotation angle of balancer shafts 2a, 2b Therefore, in order to balance equations (1) and (2), F _H =
Since it is necessary that F _B , the following formula holds true.

W _H /g・R・ω _A ²・{cos(β+θA)+Q ₂ cos2(β+
θA)+}=2W _B /g・R _B・ω _B ²・sinθ _B …(3) Here, if R=R _B , ω _A ²・{cos(β+θ _A )+Q ₂ cos2θ(β+θ _A ) }=2
W _B /W _H・ω _B ²・sinθ _BAlso , if Wγ=2W _B /W _H , ω _B ² /ω _A ² = cos(β+θ _A )+Q ₂ cos2θ(β+θ _A )
/Wγsinθ _B Here, since ω _A = dθ _A /dt, ω _B = dθ _B /dt, Also, Wγ=(dθ _A /dθ _B ) ² cos(β+θ _A )+Q ₂ cos2θ(β
+θ _A )/sinθ _B Next, if the pitch radius of the driving gear 4 is γ _A , the pitch radius of the driven gear 5 is γ _B , and the center distance between the driving gear 4 and the driven gear 5 is l, then γ _A = f(θ _A ) γ _B = f (θ _B ) γ _A + γ _B = l ...Since the relationship is (5), the pitch of the driving gear 4 and the driven gear 5 is adjusted so as to satisfy the equations (5) and (4). Once the profile is determined, primary and secondary or higher reciprocating inertia forces can be eliminated at the same time. the result,
A trial calculation revealed that these gears 4 and 5 have an approximate elliptical shape as shown in the figure.

[Elimination of rolling moment]

Next, talking about eliminating the rolling moment, the following configuration is used to eliminate the rolling moment that is a vibration-exciting force due to the side pressure of the piston 6 due to fluctuations in rotational torque. That is,
The positions of the balancer weights 3a and 3b are l 1 and l 2 from the center point of the crankshaft 1 in the piston axis, that is, the X-axis direction, and the values of these positions _{l 1 and l 2 are} calculated using the following formula (6 ) and (7), the rolling moment can be eliminated.

That is, as is well known, since the rotation torque Tr is a combination of inertia torque and gas pressure torque, the following equation naturally holds true.

Tr=a ₀ + _h=∞ 〓 ^h=1 √′ ² + _h ² sin (hθ _A +eh) …(6) Here, a ₀ : Average torque a′ _h , b _h : h-order (synthetic) torque harmonization b _h = Same as gas pressure torque harmonic coefficient a′ _h = Addition of coefficients of the same order of inertia torque and gas pressure torque θ _A : Crank rotation angle e _h : Phase angle = tan ^-1 b _h /a' _h Therefore, if we try to approximately balance the rotational torque Tr using the positions l ₁ and l ₂ of the two balancer weights 3a and 3b, the following equation (7) holds, so _h=∞ 〓 〓 ^h=1 √′ _h ² + _h ² sin(hθ _A +e _h ) W _B /g・R _B・{ω
_B } ² (l ₁ −l ₂ )・sinθ _B …(7) Therefore, in order to satisfy this equation (7), the positions l ₁ , l ₂
If you calculate and install 3a and 3b at that position,
It is possible to approximately balance the rotational torque, that is, the rolling moment.

The above explanation is based on a calculation example for one cylinder, but for a two-cylinder 360° crank arrangement, the reciprocating inertia of secondary and higher orders and the rolling moment can also be roughly eliminated in the same way. .

[Effects of the invention] According to the invention, since the rotation of the crankshaft, which rotates at an appropriate constant rate, is linked to the shaft for the balance weight by changing the angular velocity, the shaft for the balance weight can be used for primary and secondary rotation with a minimum number of shafts. Since it is possible to eliminate the reciprocating inertia force greater than or equal to the following, it is possible to provide an engine with a simple structure, a compact structure, and less vibration.

Since the pair of balance weights are placed at different distances from the center of the crankshaft on the opposite side of the piston, just by using these positions, rolling moments can be almost eliminated, and one or two cylinders can be rotated 360°. For internal combustion engines with a crank arrangement, all vibrations can be suppressed.

[Brief explanation of the drawing]

The drawings are explanatory diagrams of embodiments of the present invention. 2a, 2b...Balancer shaft, _l1 , _l2 ...Positions of balancer weights 3a, 3b.

Claims (1)

[Scope of utility model registration request] A pair of balancer weights that rotate in opposite directions to eliminate the reciprocating inertia force of the internal combustion engine are placed on both sides of the piston axis and at different distances from the center of the crankshaft on the opposite side of the piston. A balancer device for an internal combustion engine with a one-cylinder or two-cylinder 360° crank arrangement, in which the rotation of the crankshaft is linked to the balance weight shaft by changing the angular velocity.