JPH0384246A - Balancer device for engine - Google Patents

Abstract

PURPOSE:To improve an effect of reducing the generation of noise in a car room and to reduce the weight of an engine outer jacket part by a method wherein drive of a moving structure balancer mass is controlled according to an engine running condition, a phase angle between the two masses is set to an optimum position according to a running condition. CONSTITUTION:An oil passage 30 opened to the rear end part of a mass shaft 22 is communicated to an oil passage 27 of the mass shaft 22. A control valve 28 is located in a manner to open and close the oil passage 30. A control solenoid 29 moves forward an actuating shaft 29a during energization to operate the valve 28 into the closed state, and during non-energization, the actuating shaft 29a is moved backward to operate the valve 28 into an operating state. A belt for driving a balancer shaft is run around the mass shaft 22 and fixed and therefore, only the mass shaft 24 side is rotated. Rotation of the mass shaft 24 causes rotation of a small balancer mass 23, and a phase angle between the small balancer 23 and the large balancer 21 is varied.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an engine balancer device, and particularly to a technique for reducing secondary rolling moment.

(Prior art) Conventionally, as an engine balancer device, JP-A-62-1
Those shown in Japanese Utility Model Publication No. 84258 and Japanese Utility Model Application No. 62-143844 are known.

That is, the former is equipped with a variable balancer that rotates synchronously with the engine output shaft, generates an excitation force in the opposite direction when the torsion occurs in the torsional vibration mode, and has a variable function that cancels out the torsional vibration. The effect of canceling torsional vibration is increased as the engine load decreases.

The latter includes a synchronous generator connected to a crankshaft, a balancer shaft having a weight eccentric from the shaft center, and a synchronous generator connected to the balancer shaft and operated in synchronization with the synchronous generator. The apparatus includes an electric motor and means for adjusting the rotational phase of the balancer shaft and the crankshaft so that the excitation force by the balancer shaft cancels out the excitation force by the crankshaft.

(Problems to be Solved by the Invention) However, the conventional balancer device described above has a structure that eliminates the excitation force, that is, the secondary rolling moment, generated in the engine depending on the engine load and rotation speed. Therefore, under certain predetermined engine operating conditions, the secondary rolling moment is eliminated, but under other operating conditions, the above-mentioned reduction of the secondary rolling moment is not sufficient, etc. There was a problem in that it was not possible to reduce the secondary rolling moment by matching the operating conditions.

As a result, the effect of reducing noise inside the vehicle interior was not satisfactory, and the actual situation was that it was difficult to design lightweight engine exterior parts.

Therefore, in view of the above-mentioned conventional problems, the present invention adopts a configuration in which the offset amount of the large and small balancer masses in the balancer is made variable according to the engine operating conditions, thereby achieving an effective system under all engine operating conditions. It is an object of the present invention to provide a balancer device that can obtain a secondary rolling moment reduction effect.

Means for Solving the Problems> For this reason, the engine balancer device of the present invention includes a pair of balancers having a rotation center substantially parallel to the crank axis.
Each of the pair of balancers is provided with two large and small balancer masses, and each of the pair of balancers has a large balancer mass and a small balancer mass. At least one of the masses has a movable structure capable of varying the mutual phase angle of both masses, and a drive means for driving the movable structure balancer mass and a control means for controlling the drive means according to engine operating conditions are provided. composition.

<Function> In such a configuration, by changing the setting of the phase angle between the large balancer mass and the small balancer mass according to the engine operating conditions, such as engine speed and load, the secondary The rolling moment can be sufficiently reduced, and the secondary rolling moment can be reduced by matching all operating conditions.

Therefore, the noise reduction effect in the vehicle interior becomes satisfactory, and furthermore, the weight reduction of the engine exterior parts can be easily designed.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, the small end 3a of the connecting rod 3
is connected to a piston 2 that slides within the cylinder 1 of an in-line four-cylinder engine, and its large end 3b is connected to a crank pin 4 of a crankshaft (not shown). The crank journal 5 of the crankshaft is supported by a bearing (not shown) formed in the engine.

A first balancer 7a is arranged on the left side in the figure, and a second balancer 7b is arranged on the right side of the left and right sides with the engine crankshaft in between. Both balancers 7a,
, 7b, each of the balancer shafts 7A.

The cylinders 7B each have a rotation center substantially parallel to the axial direction of the crankshaft, and are disposed at a predetermined distance in the axial direction of the cylinder 1 to form a pair. Both balancer shafts 7A and 7B rotate in opposite directions at twice the rotational speed of the crankshaft via a chain, chain sprocket, etc. (not shown).

In Fig. 1, 9 is an oil pan, 10 is an oil filter, 11 is a combustion chamber, 12a is an intake valve, 12b is an exhaust valve, 13 is an intake pipe, 14 is an exhaust pipe, 15 is an intake throttle, and 16 is a cam. The shaft, 17 is a fuel injection valve, and 18 is a spark plug.

Here, each of the pair of balancers 7a and 7b is provided with two large and small balancer masses, which will be described later.

In each of the pair of balancers, at least one of the large balancer mass and the small balancer mass is made into a movable structure capable of varying the mutual phase angle of both masses, and a driving means 19 for driving the movable structure balancer mass; A control unit 20 is provided as a control means for controlling the drive means 19 according to engine operating conditions.

The movable structure of the balancer mass, the structure of the driving means, and the control means will be explained next.

That is, in FIGS. 2 and 3, there is provided a mass shaft 22 with a large balancer mass 21 integrally formed on its outer periphery, and a mass shaft 24 with a small balancer mass 23 fitted and fixed on its outer periphery. . The mass shaft 24 is composed of a cylindrical body with one end closed, and the end of the mass shaft 22 is inserted into the interior from the open end.

Between the inner circumferential surface of the mass shaft 24 and the outer circumferential surface of the mass shaft 22, helical gears 24a, 22a are formed on the inner circumferential surface and the outer circumferential surface.
The helical gear 25a is fitted with the helical gear 25a.

25b is formed on the inner peripheral surface and the outer peripheral surface of the plunger 25.
is interposed. The outer periphery of the mass shaft 22 between the end face of the plunger 25 and the end face of the parallel mass 21 is
A return spring 26 is interposed which always elastically urges 5 to the left in the figure.

An oil passage 27 is formed in the mass shaft 22 with one end open on its outer peripheral surface and the other end opened on its distal end surface, and oil is passed through the passage 27 to the plunger 25 inside the mass pongee 24.
It can be installed on the front side. The introduction of such oil is carried out by a control valve 2 that drives the drive means 19.
8 and a control solenoid 29.

That is, in the oil passage 27 of the mass shaft 22, the mass shaft 2
An oil passage 30 that opens at the rear end of the two is communicated with each other. The control pulp 28 is provided to open and close the oil passage 30. Further, the control solenoid 29 has its operating shaft 29 when energized.
a is moved forward to operate the valve 28 to the closing side, and when the power is not energized, the operating shaft 29a is retreated to operate the valve 28 to the open side.

Therefore, when the oil passage 30 is closed, the oil passage 2
7 does not drain, a predetermined hydraulic pressure is applied to the front side of the plunger 25 inside the mass shaft 24, and the oil passage 3
When 0 is opened, the oil in the oil passage 27 drains,
The hydraulic pressure applied to the front side of the plunger 25 inside the mass shaft 24 is released.

The hydraulic pressure applied to the front side of the plunger 25 inside the mass shaft 24 acts to press the plunger 25 rearward. Therefore, the plunger 25 receiving the hydraulic pressure moves axially to the stopper 31 while rotating since it is fitted into the helical gear.

At this time, the belt for driving the balancer shaft is wrapped around the mass shaft 22 and is fixed, so that only the mass shaft 24 side rotates.

The rotation of the mass shaft 24 causes the small balancer mass 23 to rotate, and the mutual phase angle between the small balancer mass 23 and the large balancer mass 21 is varied.

Here, sensors 32 and 33 are provided to detect engine speed and load as engine operating conditions, and the control unit 20 controls the control solenoid 29 based on detection signals from these sensors 32 and 33.
Switching system i.

Next, the functions and effects of this configuration will be explained.

In addition, FIG. 4 shall be referred to for the following description.

The balancers 7a and 7b are considered to be divided into two components.

The vertical excitation force is Fm = 2ms r= ω” cos2 θ
The Z moment is Ml=0 172 mmt The vertical vibration force generated by r□ is F
□2-0 The left and right excitation force is F'mlV = -mmtrm + 63" sin 2
The θY moment is M=m+ -ms+rm+J)"
n2θ On the other hand, the vertical secondary excitation force generated by the 4-cylinder engine is: F=4mrω” A, cos 2θZwhere, m: Mass of reciprocating part r: Crank radius ω: Angular velocity θ: Crank angle Az: l/ λ+1/4λ3+... λ: ffi/r (Il: connecting rod length) Also, the secondary rolling moment is the moment of inertia and explosive force M=,
Mc. Divided into □, each Ma-4mr”ω”Bzs
i n2θMc,,, w−πD”r (a, s i
n2θ+b2cos2θ〉, where D is the cylinder diameter, B2: 1/2+1/32λ4+...8g+1) ffi is the harmonic coefficient determined by the indicated mean effective pressure, and the combined excitation force is Fyoyat=Fm+Fm+y+F=(2mmrsω"
+4mrω”Az)cos2θZ ms+rm+ω”
5in2θY Now, if 2 m m r s = 4 m r A z, then Ftotac=-mml r+uωts in
2θY.

Furthermore, the resultant moment is Mvotat= (mmIr sr d=ω” + 4
m r "Bzω"-x D"ra,) s i
n 2θ-zD”rb.

cos2θ, (rrl+ r sr d, ω”+ 4 m r ”B
m□, rm++ that minimizes zω” zD”raz)
Determine dm. This decision depends on,ω,a,.

Therefore, in this embodiment, the first and second balancers 7
Large and small balance mass 21.23 in a and 7b respectively
The balancer 7a adjusts the phase angle of the balancer 7a.

The setting for low rotation of 7b is as shown in Fig. 5 (a), and the setting for high rotation is as shown in Fig. 5 (b).
Do as shown below.

Note that 34 in the figure is a composite vector.

When the vibration level with respect to engine speed is expressed separately for each engine load when setting for low speed and when setting for high speed, the graph shown in Figure 6 (a) at medium load is obtained, When the load is high, the graph becomes as shown in FIG. 4(b).

Therefore, by switching between the low-speed setting and the high-speed setting at the switching points shown in the graphs in FIGS. 6(a) and 6(b), it is possible to effectively reduce the vibration level.

FIG. 7 is a map showing the above switching state.

As described above, it is possible to sufficiently reduce the secondary rolling moment under any operating conditions, and it is possible to reduce the secondary rolling moment by matching all operating conditions.

As a result, it is possible to improve the noise reduction effect in the vehicle interior, and it is also possible to effectively design lightweight engine exterior parts.

Incidentally, the configuration of the above embodiment does not indicate any structural limitations of the present invention, and the point is that at least one of the large balancer mass and the small balancer mass in each of the pair of balancers is changed so that the mutual phase angle between the two masses is varied. In addition to making a movable structure to obtain
a drive means for driving the movable balancer mass; a control means for controlling the drive means according to engine operating conditions;
It is sufficient if the configuration includes the following.

Further, in the above embodiment, both balancers 7a.

Although the large balancer mass 21 and the small balancer mass 23 are provided on the same axis in each of 7b, they may be provided on different axes. In this case, there will be four balancer shafts.

<Effects of the Invention> As explained above, according to the balancer device according to the present invention, at least one of the large balancer mass and the small balancer mass in each of a pair of balancers has a movable structure that can vary the phase angle between both masses. As a result, the drive of the movable balancer mass is controlled according to the engine operating conditions, and the phase angle between both masses is set to the optimum position according to the operating conditions, so the secondary rolling moment can be reduced under a wide range of operating conditions. Can be reduced.

Therefore, the noise reduction effect in the vehicle interior can be improved, and it is also possible to easily design lightweight engine exterior parts, which is very useful.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross-sectional view of an engine showing an embodiment of the balancer device according to the present invention, and FIG. 2 is a cross-sectional view showing the movable structure and drive means of the balancer mass in the same embodiment. Fig. 3 is a diagram showing the configuration of the balancer mass as described above, (a) is a perspective view, (b) is a view as seen from arrow A in (a), and Fig. 4 is a diagram for explaining the calculation of the phase difference balancer. , Figures 5(a) and (b) are schematic diagrams showing the settings of the balancer mass, and Figure 6(
a) and (b) are graphs showing the vibration level against the engine speed when set for low speed and when set for high speed, divided by engine load, and Figure 7 shows the switching state of the same settings. This is a map that represents

Claims (1)

[Claims] A pair of balancers having rotation centers substantially parallel to the crank axis are arranged on both left and right sides with the crankshaft in between, and each of the pair of balancers is provided with two large and small balancer masses. In each of the balancers, at least one of the large balancer mass and the small balancer mass has a movable structure capable of varying the phase angle between the two masses, and a driving means for driving the movable structure balancer mass;
A balancer device for an engine, comprising: control means for controlling the drive means according to engine operating conditions.