JP2023109488A - balancer device - Google Patents

Abstract

To suppress generation of deviation in phase between a driven gear and a balance shaft.SOLUTION: A balancer device for an internal combustion engine includes: a driven gear 13 engaging a crank gear installed to a crankshaft; a friction ring 14 press-fitted and fixed into an inner periphery of the driven gear 13; and a balance shaft 11 inserted into an inner periphery of the friction ring 14. The friction ring 14 has a shape which is asymmetric with respect to a rotation direction and generates different frictional forces depending on a rotation direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a balancer device for an internal combustion engine.

Internal combustion engines are used as power sources for vehicles. Patent Document 1 describes an internal combustion engine, including a crankshaft, a crank gear drivingly connected to the crankshaft, a first balance shaft, and a damping mechanism that allows relative rotation of the first balance shaft. A balancer device is disclosed that includes a first driven gear that is driven by a driven gear.

Here, when the first driven gear and the counter gear fixed to the first balance shaft rotate relative to each other within a predetermined rotation phase range, the damping mechanism generates a frictional force that attenuates the relative rotation. The generated friction damper, the first driven gear, and the first balance shaft are elastically deformed only when the relative rotation exceeds a predetermined rotation phase range, and the elastic force acts against the relative rotation. It has stopper rubber.

By adopting such a configuration, even if a rotational force with a mixture of low frequency components and high frequency components is input as vibration components, the occurrence of resonance phenomena caused by these vibration components can be avoided by damaging or degrading the damping mechanism. can be suitably suppressed without causing

JP-A-2001-193794

The balancer device disclosed in Patent Document 1 has a problem that the rotational phases of the first driven gear and the first balance shaft are not fixed. This is because the rotational phase is determined by each of the rotational force from the crank gear, the frictional force of the friction damper, and the rotational sliding resistance of the balance shaft. This is because there is no configuration for positively controlling the rotation phase. Therefore, in an engine that is used as an internal combustion engine, the actual balance ratio of the balance shaft may decrease, resulting in deterioration of vibration.

SUMMARY OF THE INVENTION The present invention provides a balancer device that suppresses engine vibration.

A balancer device according to the present invention is a balancer device for an internal combustion engine, comprising: a driven gear meshing with a crank gear provided on a crankshaft; a friction ring press-fitted and fixed to an inner circumference of the driven gear; and a balance shaft inserted into the inner circumference of the friction ring, the friction ring having an asymmetrical shape with respect to the direction of rotation, and generating different frictional forces depending on the direction of rotation.
As a result, it is possible to suppress the occurrence of a phase shift between the driven gear and the balance shaft.

As a result, vibration of the engine can be suppressed.

It is a perspective view which shows the structural example of a balancer apparatus. It is a front view of a friction ring. FIG. 5 is a front view showing another example of the phase state of the friction ring; FIG. 4 is a front view of a state in which the stopper rubber and the pawl are in the first phase state; FIG. 10 is a front view of a state in which the stopper rubber and the pawl are in the second phase state; FIG. 4 is a diagram showing the change in phase when the number of revolutions of the engine is changed using the associated friction ring;

Embodiment 1
FIG. 1 is a diagram showing an example of the configuration of a balancer device 1 for an internal combustion engine. As shown in FIG. 1, the balancer device 1 includes a first balance shaft 11, an annular damper cover 12, a first driven gear 13, a friction ring 14, a stopper rubber 15, a pawl 16, and a second 1 drive gear 17 , a second balance shaft 18 , a second driven gear 19 and a balance mass 20 . Note that the internal combustion engine will be described as an engine.

The first balance shaft 11 is a shaft that extends in a predetermined direction, and the tip portion thereof is press-fitted and fixed to the damper cover 12 .

Hereinafter, the extending direction of the first balance shaft 11 will be described as the extending direction of the balancer device 1 . Furthermore, the direction perpendicular to the extending direction of the first balance shaft 11 is defined as the radial direction, and the direction around the axis with the extending direction of the first balance shaft 11 as the axial direction is defined as the circumferential direction. Alternatively, it will be explained as the direction of rotation. Also, the viewpoint from the front direction in FIGS. 2, 4, and 5, which will be described later, is the viewpoint from the extension direction side.

The cup-shaped damper cover 12 is provided with a hole through which the first balance shaft 11 can be press-fitted. Further, a plurality of stopper rubbers 15 are provided inside the cup-shaped interior of the damper cover 12 . A claw 16 provided on the first driven gear 13 described later is accommodated between the plurality of stopper rubbers 15 .

The ring-shaped first driven gear 13 is a gear having a plurality of teeth along the circumferential direction of the outer circumference, and meshes with a crank gear (not shown) of the crankshaft. An annular friction ring 14 is press-fitted and fixed to the inner circumference of the first driven gear 13 .

Furthermore, the first driven gear 13 is provided with a plurality of pawls 16 projecting in the extension direction. Specifically, each of the plurality of claws 16 protrudes toward a stopper rubber 15 provided on the damper cover 12 .

Here, the first balance shaft 11 is movable with respect to the first driven gear 13 , and its movable range is regulated by the damper cover 12 and the stopper rubber 15 . Here, the stopper rubbers 15 are provided in a state in which they are annularly continuous and spaced apart from each other by a predetermined distance when viewed from the front. As will be described later, a plurality of claws 16 are arranged between these stopper rubbers 15 .

FIG. 2 is a front view showing an example of the friction ring 14 from the front direction. As shown in FIG. 2, the friction ring 14 is formed of an annular portion 14a and a plurality of protrusions 14b projecting inwardly from the annular portion 14a. The plurality of protrusions 14b are formed continuously in the circumferential direction of the annular portion 14a and have an asymmetrical shape in the circumferential direction. Furthermore, as shown in FIG. 2, the direction of rotation of the first balance shaft 11 is here counterclockwise.

Further, of the protruding portion 14b of the friction ring 14, the inner vertex portion is the vertex 31, the tapered portion provided clockwise from the vertex 31 to the annular portion 14a is the first tapered portion 32, and the tapered portion is counterclockwise from the vertex 31. The tapered portion extending to the annular portion 14 a in the direction is referred to as a second tapered portion 33 .

As shown in FIG. 2, the first tapered portion 32 of the one protrusion 14b of the friction ring 14 is shorter than the second tapered portion 33 in the circumferential direction. Also, the first balance shaft 11 is inserted into the inner circumference of the friction ring 14 .

Here, FIG. 3 shows that the first balance shaft 11 is inserted through the friction ring 14 on the inner circumference of the first driven gear 13, and the first driven gear 13 is attached to the damper cover 12 through the pawl 16. FIG. 4 is a cross-sectional view showing a connected state;

Returning to FIG. 1 , the first drive gear 17 is fixed to the first balance shaft 11 . Here, as shown in FIG. 1, regarding the positional relationship in the extending direction of the damper cover 12, the first driven gear 13, and the first driving gear 17, the damper cover 12 is provided on the distal end side, and the first driving gear 17 is provided on the rear end side, and the first driven gear 13 is arranged between the damper cover 12 and the first drive gear 17 .

The second balance shaft 18 is a shaft arranged parallel to the first balance shaft 11 . That is, the extending direction of the second balance shaft 18 and the extending direction of the first balance shaft 11 are parallel. A second driven gear 19 is fixed to the second balance shaft 18 .

A second driven gear 19 fixed to the second balance shaft 18 meshes with a first drive gear 17 fixed to the first balance shaft 11 . Therefore, when the first balance shaft 11 rotates, force is transmitted to the second driven gear 19 via the first drive gear 17 , and rotational force is applied to the second balance shaft 18 .

A balance mass 20 is connected to each of the first balance shaft 11 and the second balance shaft 18 to balance the inertial forces of the engine.

Next, the operation of the balancer device 1 and the effect of each part will be described. Here, first, the occurrence of phase change between the first driven gear 13 and the first balance shaft 11 and the influence of the phase change will be described.

The first balance shaft 11 is rotationally movable with respect to the first driven gear 13 . At this time, the movable range of the first balance shaft 11 is restricted by the stopper rubber 15 provided on the damper cover 12 and the pawl 16 .

FIG. 4 shows a state in which the first driven gear 13 and the first balance shaft 11 are in a predetermined phase in the rotational direction. Here, the first driven gear 13 is driven by the crank gear to rotate in the arrow direction shown in FIG.

At this time, as shown in FIG. 4, the pawl 16 provided on the first driven gear 13 and the damper cover 12 fixed to the first balance shaft 11 are in a predetermined phase. A state in which the counterclockwise end of the pawl 16 is close to the clockwise end of the stopper rubber 15 is defined as a first phase state.

It should be noted that the balance mass 20 is connected to the first balance shaft 11 and the second balance shaft 18 so that the balance is optimized in the first phase state.

On the other hand, the driving force that the first driven gear 13 receives from the crankshaft changes in a complicated manner from moment to moment. Therefore, the first balance shaft 11 receives torque from the first driven gear 13 via the friction ring 14, but the torque is not necessarily equal for different rotation directions. Therefore, the first phase state shown in FIG. 4 is not stabilized, and depending on the operating conditions, the phase state shown in FIG. 5 or intermediate phase states shown in FIGS. state may occur.

Note that the phase state shown in FIG. 5 is referred to as a second phase state. Specifically, the second phase state is a state in which the clockwise ends of the claws 16 are close to the counterclockwise ends of the plurality of stopper rubbers 15 .

6(a) and 6(b) illustrate the phase of this first driven gear 13 and the first balance shaft 11, i.e. the pawl 16 provided on the first driven gear 13, using the associated friction ring. , and shows an example of actually measuring the state of the phase of the damper cover 12 fixed to the first balance shaft 11 . FIG. 6(a) shows a state in which the number of rotations of the engine is changed over time, and FIG. 6(b) shows a phase state at that time. Also, as used herein, a related friction ring is a friction ring similar to friction ring 14 in which first tapered section 32 and second tapered section 33 are symmetrically formed. .

More specifically, as shown in FIGS. 6A and 6B, when the engine speed is around 3000 rpm, the first phase state shown in FIG. 4 changes to the state shown in FIG. Transition to the second phase state. Then, the second phase state is maintained until the engine speed reaches around 1500 rpm.

At this time, since the balance mass 20 is based on the first phase state shown in FIG. By transitioning to the state, a phenomenon occurs in which the actual balance ratio is lowered and the vibration of the engine is increased.

On the other hand, as described above, in the balancer device 1, the first tapered portion 32 of the friction ring 14 is shorter in the circumferential direction than the second tapered portion 33 and formed asymmetrically. can be used.

That is, since the protrusion 14b of the friction ring 14 has an asymmetrical shape with respect to the rotational direction of the first balance shaft 11, the torque transmitted by friction from the first balance shaft 11 is also asymmetrical. . Therefore, the friction ring 14 can generate different frictional forces depending on the rotation direction of the shaft arranged inside.

As a result, the phase shift between the first driven gear 13 and the first balance shaft 11 is less likely to occur. That is, the phases of the first driven gear 13 and the first balance shaft 11 are likely to be maintained in the first phase state shown in FIG. It is possible to suppress the occurrence of state transitions. Therefore, since the number of phase changes is reduced, the occurrence of engine vibration can be suppressed.

It should be noted that the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the scope of the invention. That is, the above description is appropriately omitted and simplified for clarity of explanation, and those skilled in the art can easily change, add, and convert each element of the embodiment within the scope of the present invention. Is possible.

1 Balancer Device 11 First Balance Shaft 12 Damper Cover 13 First Driven Gear 14 Friction Ring 14a Annular Part 14b Projection 15 Stopper Rubber 16 Claw 17 First Drive Gear 18 Second Balance Shaft 19 Second Driven Gear 20 Balance Mass 31 vertex 32 first tapered portion 33 second tapered portion

Claims (1)

A balancer device for an internal combustion engine,
a driven gear that meshes with a crank gear provided on the crankshaft;
a friction ring press-fitted and fixed to the inner periphery of the driven gear;
a balance shaft inserted into the inner circumference of the friction ring,
The friction ring has an asymmetrical shape with respect to the direction of rotation, and generates different frictional forces depending on the direction of rotation.
balancer device.

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