JPH09250597A - Balancer device for four-cylinder engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the balancer device for a deformed in-line type four- cylinder engine, which can be manufacture without changing a former production equipment to a great extent, and causes the whole of primary and secondary inertia force, and exciting moment to be zero. SOLUTION: In the balancer device for a four-cylinder engine where two balancing shafts 11 and 12 for constant velocity in isotropic direction and constant velocity in reverse direction, are provided in parallel with a crank shaft with respect to the crankshaft 6 whose arrangement of each crank pin is 0 deg. for a first cylinder, 90 deg. for a second cylinder, 270 deg. for a third cylinder and 180 deg. for a fourth cylinder respectively, mass for a crank rotating portion in the equivalent mass system of a piston-crank mechanism, shall be less than one half of mass for a reciprocating portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balancer device for a modified four-cylinder engine, which can completely eliminate the primary and secondary inertial forces and the inertia couple and the rolling vibration moment around the crankshaft due to the primary inertial force. The present invention relates to a balancer device for making the value 0.

[0002]

2. Description of the Related Art The crankpin arrangement of a four-cylinder, four-cycle engine that has been widely adopted in the past is the first cylinder and the fourth cylinder.
The cylinders are 0 °, the second and third cylinders are 180 °, and the four cylinders are all within one plane, which is called a one-plane crank arrangement. In such a 1-plane crank 4-cylinder engine, the primary inertial force and the inertial couple are zero, but the secondary rolling excitation moment around the crankshaft due to the secondary inertial force and the primary inertial force remains.

If we try to eliminate this secondary inertial force,
It is necessary to provide two balancer shafts in the double speed equal direction and the double speed reverse direction with respect to the crankshaft at symmetrical positions on both sides of the cylinder.

In order to eliminate the secondary rolling moment, it is necessary to offset the balancer shaft by a certain amount in the cylinder direction.

Such a balancer shaft is required to satisfy certain geometrical conditions, which greatly limits the degree of freedom in design.

In addition, since the balancer shaft rotates at twice the speed of the crankshaft, a high-speed engine has various problems in terms of durability of the balancer bearing and mechanical noise.

On the other hand, unlike the above-mentioned 1-plane crank pin arrangement, the crank pins are 0 ° for the first cylinder and 9 for the second cylinder.
A 2-plane crank arrangement structure is proposed in which the planes of the first and fourth cylinders and the planes of the second and third cylinders form two orthogonal planes, with 0 °, the third cylinder 270 °, and the fourth cylinder 180 °. Has been done. An engine with such a 2-plane crankpin structure is
Since the effect of canceling the reciprocating motion partial mass between the cylinders is small, it is difficult in terms of vibration prevention technology. On the contrary, in the case of motorcycles, the combustion of the engine in terms of vibration amplitude, S / N ratio and frequency The pressure is felt by the body, the acceleration feeling is improved, and the driving feeling becomes very good. Therefore, it is desired to put the vibration suppression technology into practical use in such a two-plane crank engine structure.

In order to solve the above-mentioned various problems of the one-plane crankpin structure, the engine has a two-plane crankpin structure, and one constant-speed reverse-rotating balancer shaft is provided in parallel with the crankshaft, and is mounted on the balancer shaft. It has been proposed to reduce engine vibration by providing two balancer weights for the first and second cylinders and for the third and fourth cylinders (JP-A-57-69173).

[0009]

However, in the four-cylinder engine described in this publication, the rotational partial mass of each cylinder is basically equivalent to the crank pin position conversion value and is oriented in the opposite direction of the pin. Should be one-half of the reciprocating mass of each cylinder. However, it is difficult to install the rotating part corresponding to such a mass in the same space with the same member as the four-cylinder engine of the 1-plane crankpin array which has been widely used in the past, and it is assumed that the rotating part is installed in the same space. If this is the case, it is necessary to use heavy metal counterweights and titanium connecting rods, which is disadvantageous in terms of technical structure, assembly, and price, and productivity is poor.

Further, in a high rotation speed engine, there is a problem in terms of durability due to a decrease in torsional natural frequency.

On the other hand, the inventors of the present invention used a two-plane crank (first crank) having a configuration in which the first moment is minimized and the second moment is maximized in an arrangement different from the above crank arrangement.
Cylinder 0 °, second cylinder 180 °, third cylinder 270 °, fourth
Acceleration and vibration feeling were improved by using a cylinder (90 °), but it was difficult to suppress vibration due to the first and second moments. Therefore, the inventors of the present invention changed the form of the crank to adopt a two-plane crank in which the second moment is 0 and the first moment is maximum, and the balancer completely eliminates the first moment.

The present invention has been made in view of the above points, and can be produced without significantly changing the conventional production equipment, and the primary and secondary inertial forces and inertia couples, and the primary inertial forces. It is an object of the present invention to provide a balancer device for a modified row 4-cylinder engine in which all the rolling vibration moments around the crankshaft are zero.

[0013]

In order to achieve the above object, according to the present invention, a crankshaft having a crankpin arrangement of a first cylinder 0 °, a second cylinder 90 °, a third cylinder 270 °, and a fourth cylinder 180 °. On the other hand, in a balancer device for a four-cylinder engine in which two balancer shafts for constant velocity equal direction and constant velocity opposite direction are provided in parallel with the crankshaft, the crank rotating partial mass of the piston / crank mechanism equivalent mass system is reciprocated. Partial mass 2
Provided is a balancer device for a four-cylinder engine, which is characterized by being less than one-third.

In such a balancer device, if the rotating partial mass of the crank is set to 0 or smaller than half of the reciprocating partial mass of each cylinder, the primary pitching vibration moment about the crankshaft is converted into the crankshaft. On the other hand, the primary pitching vibration moment and the primary yawing vibration moment generated by the two balancer shafts in the constant velocity equal direction and the constant velocity opposite direction can cancel and cancel each other.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The balancer device of the present invention will be further described below with reference to FIGS. 1, 2 and 3. In the following description, the coordinate system uses the right-handed coordinate system with the z-axis facing the front of the page. The rotation direction of the crank is counterclockwise when viewed from the front side of the drawing.

FIG. 1 is a structural explanatory view showing one cylinder of a four-cylinder engine to which the present invention is applied, and FIG. 2 is an explanatory view of a crank arrangement of four cylinders. The crank 20 coupled to the crankshaft 6 is connected to the connecting rod 21 via the crankpin 23.
Is further connected to the piston 22 via the piston pin 24. The mass point of the reciprocating partial mass of each cylinder is the position of the piston pin 24, and the mass point of the rotating partial mass is the position of the crank pin 23. As shown in FIG. 2, in this engine, the crank pin arrangement of each of the four cylinders is
The crank 20a of the cylinder is 0 °, and the crank 20 of the second cylinder is
b is 90 °, the crank 20c of the third cylinder is 270 °, and the crank 20d of the fourth cylinder is 180 °, which is a two-plane crank pin array structure.

The vibration moment generated by the reciprocating partial mass of the engine having such a crank structure is calculated as follows.

Cylinder pitch is l, reciprocating part mass is m,
When the angular velocity is ω and the crank radius is r, the primary pitching moment My1 is expressed by the following mathematical expression (1).

[0019]

[Equation 1]

The secondary pitching moment My2 has a quadratic term of 0 as shown in the following mathematical expression (2), so My
2 = 0.

[0021]

[Equation 2]

Mass of rotating portion of the crankshaft (converted to crank pin position, and is assumed to be facing in the opposite direction of the pin)
Is less than one half of the reciprocating mass of each cylinder, A <1,
When A + B = 1, the moment of the following formula (3) is generated. Here, A and B are ratios that represent the share ratios of the rotating part mass of the crankshaft and the constant velocity and equal direction balancer,
For example, when the rotating partial mass of the crankshaft is ½ of the reciprocating partial mass of each cylinder, A = 1 and B = 0 and the structure does not have a constant velocity equal direction balancer. This is JP-A-57-69
It corresponds to the structure of No. 173. In the case of claim 2 of the present application, A = 0 and B = 1. A may be a negative value.

[0023]

(Equation 3)

Here, the moment of the following equation (4) is generated by the balancer shaft in the constant velocity / equal direction with respect to the crankshaft, and the moment in the equation (5) is also generated by the balancer shaft in the constant velocity / reverse direction.
Generate the moment of.

[0025]

(Equation 4)

[0026]

(Equation 5)

As a result, My1 + Myc1 + My1b1 + My1b2 = 0, and the primary pitching moment is eliminated.

The vibration moment in the x direction caused by the crankshaft and the balancer shaft is expressed by the following equations (6-1) (6-2) (6-3).

[0029]

(Equation 6)

As a result, Mx1c1 + Mx1b1 + Mx1b2 = 0, which cancel each other out.

Next, the secondary rolling vibration moment about the crankshaft due to the primary inertial force will be described.

The first cylinder, the fourth cylinder 0 °, the second cylinder, and the third cylinder 180, which are the crankpin arrangements (one-plane crankpin arrangement) of a four-cylinder engine that has been widely adopted in the past, are used.
At °, vibration moment Mz1 due to the primary inertial force
Is expressed by the following mathematical expression (7), and remains as a secondary rolling excitation moment around the crankshaft.

[0033]

(Equation 7)

On the other hand, in the engine of the present invention, the crank pin arrangement is a 2-plane crank pin arrangement of the first cylinder 0 °, the second cylinder 90 °, the third cylinder 270 °, and the fourth cylinder 180 °. Excitation moment Mz1 due to secondary inertial force
Becomes Mz1 = 0 as shown in the following mathematical expression (8), and the respective cylinders cancel each other.

[0035]

(Equation 8)

In the above description, since the connecting rod mass is calculated by dividing the connecting rod mass into a general reciprocating partial mass and a rotating partial mass, in the calculation of the moment around the crankshaft, the value using the moment of inertia about the center of gravity of the connecting rod is There is an error called correction torque. However, this error was relatively small and was ignored.

FIG. 3 is a basic configuration diagram of the balancer device according to the embodiment of the present invention. A gear wheel 31 is fixed to the crankshaft 6, and the first balancer shaft 11 is rotated in a constant velocity and equal direction with respect to the crankshaft 6 via a chain 30 that engages with the gear wheel 31. Further, the second balancer shaft 12 is rotated in the reverse direction at a constant speed with respect to the first balancer shaft 11 via the pair of gears 14 and 15. As a result, one of the two balancer shafts rotates in the same direction at constant speed with respect to the crankshaft, and the other balancer shaft rotates in the opposite direction at constant speed. At this time, the rotating partial mass is configured to be smaller than half the reciprocating partial mass.

Next, another embodiment of the present invention will be described. In this embodiment, in a four-cylinder engine having a two-plane crankpin arrangement, the rotating partial mass of the crankshaft is zero. In this embodiment, with respect to the crankshaft,
Instead of the equations (4) and (5) in the above embodiment, the moments of the following equations (9) and (10) are generated in the constant velocity equal direction and the constant velocity opposite direction, respectively.

[0039]

[Equation 9]

[0040]

(Equation 10)

Accordingly, since Myc1 = 0, My1 + Myc1 + My1b is the same as in the above embodiment.
1 + My1b2 = My1 + My1b1 + My1b2 = 0
Therefore, the primary pitching moment is erased.

The vibration moment in the x direction by the balancer axis is given by the following mathematical formulas (11-1) and (11-2).

[0043]

[Equation 11]

Therefore, Mx1b1 + Mx1b2 = 0
And cancel each other out.

As for the secondary rolling vibration moment around the crankshaft due to the primary inertial force, Mz1 = 0 and the cylinders cancel each other out, as in the above-described embodiment.

FIG. 4 is a left side view of a motorcycle to which the present invention is applied. The front wheel 1 is supported by a front fork 3 connected to a head pipe 2, and a 4-cylinder engine 5 is mounted below a fuel tank 4 in the front part of the main frame connected to the head pipe 2. The crankshaft 6 of the engine 5 is arranged in the vehicle width direction, and the cylinders of the engine 5 are arranged along the crankshaft 6. The rotational movement of the crankshaft 6 is transmitted to the rear wheel 8 via the chain 7.

This four-cylinder engine 5 to which the present invention is applied
Is the above-mentioned two-plane crank pin arrangement, and is provided with a balancer device having two balancer shafts.

FIG. 5 is a basic configuration diagram of the balancer device (the device on the right side of FIG. 6) according to the embodiment of the present invention. FIG. 5 (A)
Is a view (cross section) from the side of the vehicle, and FIG. 5B is a view (cross section) from the front of the vehicle, that is, from the direction of FIG.
The balancer device 10 is composed of a first balancer shaft 11 that is in a constant velocity and equal direction to the crankshaft, and a second balancer shaft 12 that is in a constant velocity opposite direction to the crankshaft. Each balancer shaft 11, 1
A balance weight 13 is attached to 2. The first balancer shaft 11 may be directly connected to the crank shaft of the engine,
Alternatively, it may be connected to the crankshaft at a constant speed and in the same direction via an appropriate transmission mechanism such as a gear or a chain. The first gear 14 is fixed to the first balancer shaft 11, and the second gear having the same diameter and the same number of teeth as the first gear 14 is connected to the second balancer shaft 1.
It is fixed to 2, and these first and second gears 14 and 15 are meshed with each other. As a result, the second balancer shaft 12 rotates in the reverse direction at a constant speed with respect to the crankshaft.

The balancer device 10 as described above is mounted on both left and right sides of the vehicle body as shown in FIG. The axial arrangement of the device on the left side of FIG. 6 is symmetrical with respect to the vehicle center line of the device on the right side of FIG. Further, the phase of the balance weight 13 is at a position of 180 ° opposite phase with respect to each of the balancer shafts 11 and 12. That is, in the case of this embodiment, the balancer shafts are composed of a pair of left and right constant velocity equal directions and a pair of constant velocity opposite directions in total. The “two balancer shafts” of the present invention also includes such a configuration. In the above embodiment, the gears 14 and 15 are used to rotate the second balancer shaft 12 through the first balancer shaft 11 in the reverse direction at the constant velocity with respect to the crankshaft.
Instead of such a configuration, it may be configured to obtain rotation in the reverse direction at a constant speed from the crankshaft via an appropriate transmission mechanism. In the case of this embodiment, the layout around the engine of the conventional motorcycle (engine mounting position, arrangement of carburetor, etc.)
The balancer device is arranged such that the amount of protrusion of the crank shaft portion in the vehicle width direction can be suppressed to a small amount without changing the above, and the bank angle is not reduced.

[0050]

As described above, according to the present invention, in the in-line four-cylinder engine having the two-plane crankpin arrangement, the two crankshafts having the constant speed equal direction and the constant speed opposite direction with respect to the crankshaft are used. Since the rotational partial mass of the shaft is less than one half of the reciprocating partial mass so that the vibration moments in the x, y, and z directions become zero, the crank chamber space is not increased so much and the engine is Vibration is suppressed, and all of the primary and secondary inertial forces and inertia couples and the rolling vibration moment around the crankshaft due to the primary inertial force are reduced to 0, and an engine with a comfortable driving feeling is realized. In this case, when actually producing the engine, the existing production line can be used by making the necessary minimum changes such as the pin arrangement and the oil passage to the conventional production equipment. Further, since the two balancer shafts are couple balancers, there is no limitation on the installation position as long as they are parallel to the crank. Therefore, the balancer shaft can be provided at an appropriate position on the outer side of the crankshaft end portion or in the space portion on the side portion, and the balancer shaft in the constant velocity equal direction can also be used as a reversing device for the balancer shaft in the constant velocity reverse direction, An engine with a high degree of freedom in design can be obtained. Further, the reversing device for the balancer shaft in the constant velocity / equal direction and the balancer shaft in the constant velocity / reverse direction can also be used as the drive shaft of the rear generator. When the rotating partial mass of the crankshaft is set to 0 (in the case of claim 2), the crankshaft has the same size as the conventional 1-plane crank, and the conventional production equipment,
There are many things that can use the crankcase etc. in common.

Further, by setting the rotating partial mass of the crankshaft to more than 0 and less than half, a part of the couple (moment) required for vibration balance can be realized by the size and phase of the crank web, which is insufficient. Minutes can be covered by a balancer axis with uniform speed and direction. Therefore, it is possible to reduce the size of the constant velocity / equal direction balancer shaft as compared with the case where the rotating partial mass is set to a position lower than zero, and it is possible to reduce the occupied space and energy consumption. That is, when the crank chamber has a sufficient space, the balancer device is downsized by increasing the share of the crank itself and decreasing the share of the balancer shaft among the moments necessary to cancel the vibration. be able to.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for calculating a moment in each direction of a balancer device of the present invention.

FIG. 2 is an explanatory diagram of a crank pin array of the present invention.

FIG. 3 is a basic configuration diagram of a balancer device of the present invention.

FIG. 4 is a side view of a motorcycle to which the present invention is applied.

FIG. 5 is a basic configuration diagram of the balancer device of the present invention.

FIG. 6 is a front view of a motorcycle equipped with the balancer device of the present invention.

[Explanation of symbols]

 6: Crankshaft 10: Balancer device 11: First balancer shaft 12: Second balancer shaft 20: Crank 21: Connecting rod 22: Piston 23: Crank pin 24: Piston pin

Claims (2)

[Claims] 1. A crank pin arrangement having a first cylinder of 0 ° and a second cylinder
In a balancer device for a four-cylinder engine having crankshafts of 90 ° cylinder, 270 ° third cylinder, and 180 ° fourth cylinder, the crank rotation partial mass of the equivalent mass system of the piston / crank mechanism is halved of the reciprocating partial mass. A balancer device for a four-cylinder engine, characterized in that two balancer shafts, which are equal to or less than the constant speed and the reverse direction at the constant speed, are provided in parallel with the crankshaft. 2. The balancer device for a four-cylinder engine according to claim 1, wherein the crank rotating partial mass is set to zero.