JP2800516B2 - Engine vibration reduction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine vibration reducing device for reducing transmission of engine vibration generated from, for example, an automobile engine to a vehicle body.

[0002]

2. Description of the Related Art A general reciprocating internal combustion engine (engine) used for automobiles and the like is characterized by fluctuations in gas pressure, rotational mass,
Excitation force caused by imbalance of reciprocating mass and the like causes forced vibration having a frequency corresponding to the engine speed. This vibration is transmitted to the vehicle body via the suspension device, and gives an occupant discomfort, fatigue, and the like.

[0003] Various techniques for reducing the engine vibration as described above have been conventionally considered, and one of them is disclosed in Japanese Utility Model Laid-Open No. 59-191451. The purpose of this technique is to reduce the roll vibration among the vibrations generated from the engine, and to generate the vibration of the opposite phase to the roll vibration to reduce the roll vibration. The device includes a vibrator having an inertial mass, and a reverse vibration applying mechanism for applying a vibration having a phase opposite to that of the roll vibration to the vibrator. The reverse vibration applying mechanism includes a spring provided on both sides of the vibrator in the vibration direction to bias the vibrator, and a coil wound on the outer periphery of the vibrator. The vibration is provided by switching an excitation state of the coil. The child is vibrated in the opposite phase to the roll vibration. In this device, the vibrator acts to cancel the roll vibration of the engine.

[0004]

Incidentally, the engine vibrates with a large amplitude at the time of idling, and it is necessary to vibrate the vibrator with a large amplitude in order to cancel the vibration. However, in the above publication, no consideration is given to operating the vibrator and the spring with a small driving force, such as setting the weight of the vibrator and setting the spring. Therefore, in order to reliably reduce transmission of engine vibration during idling, a large power (electric power) is required to vibrate the vibrator with a large amplitude.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to generate large-amplitude vibration with small power and to effectively reduce engine vibration including idling vibration. It is an object of the present invention to provide an engine vibration reduction device capable of reducing the vibration.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a mass provided at an intermediate portion of a transmission path of engine vibration and capable of reciprocating in a transmission direction of the engine vibration; An elastic member provided on the way and capable of expanding and contracting in the transmission direction of the engine vibration; and driving the mass member to forcibly vibrate the mass member and the elastic member, and the vibration reduces transmission of the engine vibration. Driving means for causing the vibration system including the mass body and the elastic body to have a resonance frequency substantially equal to the frequency of engine vibration during idling.

[0007]

The engine vibration generated by the engine is transmitted to an engine vibration reduction device provided in the transmission path. In this device, a vibration system including a mass body and an elastic body is driven by a driving unit to vibrate. A load is generated by the vibration of the vibration system, and the load acts to cancel the transmission of the engine vibration.

In particular, in the present invention, the resonance frequency of the vibration system is set to be substantially the same as the frequency of the engine vibration during idling. For this reason, by utilizing the resonance of the vibration system, large-amplitude vibration is generated by the small power of the driving means. Therefore, when the engine is idling, the amplitude of the engine vibration is large, but the vibration of the large amplitude utilizing the resonance can reduce the engine vibration.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the engine vibration reducing device of the present invention is applied to an engine mount for a vehicle will be described below with reference to the drawings.

FIG. 2 is a schematic diagram showing a state where the vehicle engine 1 is mounted on the vehicle body 2. A bracket 3 extending toward the left and right sides in FIG. 2 is attached to the engine 1, and an engine mount 4 is interposed between the bracket 3 and the vehicle body 2. That is, when the engine 1 is used as a vibration source, a vibration transmission path is formed by the bracket 3, the vehicle body 2, and the like, and the engine mount 4 is disposed in the middle of the vibration transmission path. The engine mount 4 attenuates vibration generated from the engine 1 (referred to as engine vibration),
This is for suppressing the transmission of the engine vibration to the vehicle body 2.

The engine vibration includes a longitudinal component, a lateral component, and a vertical component of the engine 1. Among them, the vertical component is the largest, and the vibration of the same component is shown in FIG. This figure shows the relationship between the ignition signal when the air-fuel mixture is ignited by the ignition plug and the acceleration G of the vertical component of the engine vibration input to the engine mount 4. From FIG. 4, the cycle of the engine vibration is substantially the same as the cycle of the ignition signal, and when the phase difference Δθ has elapsed since the output of the ignition signal, the acceleration G has substantially the same value. That is, the engine vibration generated by the ignition and explosion of the air-fuel mixture and the engine mount 4
It can be seen that there is a phase difference between the vibration transmitted to and

As shown in FIG. 3, the amplitude h of the engine vibration differs for each frequency f. The amplitude h is large when the frequency f (engine speed) is low, and decreases as the frequency f increases. . For example, in the case of a four-cylinder engine mounted on an FF vehicle (a vehicle in which the engine 1 is mounted on the front part of the vehicle body 2 and drives the front wheels), the amplitude h of the engine vibration during idling is about ± 0.2 to 0 0.3 mm.

As shown in FIG. 1, the engine mount 4 has a substantially cylindrical body case 5 with a bottom. A lower bolt 6 is inserted through the bottom of the body case 5, and the body case 5 is fixed to the vehicle body 2 by the lower bolt 6. An upper rubber body 7 for buffering is adhered to the upper part of the main body case 5, and the upper opening end of the main body case 5 is closed by the upper rubber body 7. The upper rubber body 7 is for receiving a load due to the own weight of the engine 1 and a minute vibration of the engine 1. An upper bolt 8 is fixed to the upper rubber body 7 so as to face the lower bolt 6, and the engine mount 4 is fixed to the bracket 3 by the upper bolt 8.

A movable iron core 9 as a mass body and a compression coil spring 11 as an elastic body are arranged on the same line between the upper and lower bolts 8 and 6 in the main body case 5. The movable iron core 9 and the compression coil spring 11 constitute a vibration system. The movable iron core 9 has a substantially columnar shape and has an inertial mass for damping engine vibration. The compression coil spring 11 is interposed between the movable iron core 9 and the upper bolt 8 in a compressed state, and constantly urges the movable iron core 9 downward.

In the main body case 5, an electromagnetic coil 12 is disposed around the movable iron core 9. When an alternating current is applied to the electromagnetic coil 12, the electromagnetic coil 1 is turned off.
At both ends, there are magnetic poles that change with time. The change in the magnetic pole causes the movable iron core 9 to reciprocate vertically. A lower rubber body 13 is fixed to the head of the lower bolt 6 and abuts when the movable iron core 9 moves up and down as described above, thereby suppressing the impact on the lower bolt 6 and the like. .

An amplifier 14 is connected to the electromagnetic coil 12 to supply an alternating current to the electromagnetic coil 12 to operate the movable core 9. The amplifier 14 has a phase shifter 1
Oscillator 16 is connected via 5. This oscillator 1
Reference numeral 6 denotes a device for continuously generating vibrations having a constant waveform, frequency and amplitude. In this embodiment, the device outputs a sine waveform corresponding to the ignition signal of the engine 1 and synchronized with the ignition signal. The sine waveform from the oscillator 16 is input to the phase shifter 15, and the phase of the sine waveform is adjusted. The amplifier 14 amplifies the sine waveform whose phase has been adjusted as described above and outputs the amplified sine waveform to the electromagnetic coil 12.

The amplifier 14 and the phase shifter 15 are connected to a controller 17. The controller 17 takes in the engine rotation signal and the ignition signal, and controls the phase shifter 15 and the amplifier 14 based on these signals. That is, the controller 17 uses a map in which the relationship between the engine speed and the phase is defined in advance, and obtains a phase corresponding to the engine speed at that time. The controller 17 controls the amount of phase adjustment by the phase shifter 15 so that the movable iron core 9 and the compression coil spring 11 vibrate at the phase determined from the map. Further, the controller 17 uses a map in which the relationship between the engine speed and the amplitude is defined in advance, and obtains an amplitude corresponding to the engine speed at that time.
The controller 17 controls the amplitude amplification factor of the amplifier 14 so that the movable iron core 9 and the compression coil spring 11 vibrate at the amplitude obtained from the map.

In this embodiment, the electromagnetic coil 1
2. The driving means for operating the movable iron core 9 is constituted by the amplifier 14, the phase shifter 15, the oscillator 16 and the controller 17.

When the movable iron core 9 and the compression coil spring 11 are vibrated as described above, they resonate at a specific frequency. At the frequency (resonance frequency) ωn at this time, the amplitude h of the movable iron core 9 and the compression coil spring 11 increases. In the present embodiment, as shown in FIG.
Is the frequency f (6) of the engine vibration generated during idling.
00 to 700 rpm). The vertical axis in FIG. 5 represents the vibration magnification x / F,
Among them, x is the displacement of the movable core 9, and F is the force applied to the movable core 9.

Next, the operation and effect of the engine mount 4 configured as described above will be described. Engine 1
Is transmitted to the engine mount 4 provided in the middle of the transmission path. On the other hand, in the engine mount 4, an engine rotation signal and an ignition signal are captured by the controller 17, and the phase shifter 15 and the amplifier 14 are controlled based on these signals. Then, the phase of the sine waveform output from the oscillator 16 is adjusted by the phase shifter 15, and the sine waveform is amplified by the amplifier 14 and then output to the electromagnetic coil 12. When a sine waveform (alternating current) flows through the electromagnetic coil 12 in this manner, the magnetic poles generated at both ends of the electromagnetic coil 12 periodically change,
The movable iron core 9 moves up and down (vibrates). The vibration of the movable core 9 is transmitted to the upper bolt 8 and the upper rubber body 7 via the compression coil spring 11, and these vibrate vertically. And
A load is generated by the vibration of the movable iron core 9 and the compression coil spring 11, and acts to cancel the transmission of the engine vibration.

Therefore, there is a phase difference between the engine vibration generated from the engine 1 and the vibration transmitted to the engine mount 4 (see FIG. 4), and the amplitude h of the vibration generated by the engine mount 4 is large. Is different for each frequency f (see FIG. 5), but the movable iron core 9 and the compression coil spring 11 are driven with the optimum phase and amplitude by the controller 17 and the like, and the vibration transmitted from the engine 1 is reduced. Effectively damped.

In particular, in this embodiment, the resonance frequency ωn of the movable iron core 9 and the compression coil spring 11 is set to be substantially the same as the frequency f (= 600 to 700 rpm) of the engine vibration during idling. For this reason, by utilizing the resonance of the movable iron core 9 and the compression coil spring 11 at the time of idling, it is possible to generate large-amplitude vibration with small power (electric power or the like). Therefore, during idling, the amplitude h of the engine vibration increases as compared with other operations (see FIG. 3). However, due to the large-amplitude vibration utilizing the resonance, the current flowing through the electromagnetic coil 12 does not need to be increased. ,
Idle engine vibration transmitted to the engine mount 4 can be reliably attenuated. As a result, sufficiently reduced vibration is transmitted to the vehicle body 2 from the engine mount 4.

Further, as a technique for reducing engine vibration, in addition to the present embodiment, it is also possible to detect vibration input to the engine mount and perform feedback control so that the detected engine vibration becomes a target value. Conceivable. However, this may cause an unstable state due to disturbance (vibration transmitted to the engine mount from the vehicle body 2 side, vibration transmitted to the engine mount due to fluctuation in engine torque). If a filter or the like is added to the control system in order to avoid these problems, the filter causes a phase lag, and control becomes difficult.

On the other hand, in the present embodiment, the resonance frequency ω
By merely adjusting n to the frequency of the engine vibration during idling, the movable iron core 9 and the compression coil spring 11 can be automatically displaced by a large amount, and transmission of engine vibration during idling can be reduced.

The present invention is not limited to the configuration of the above-described embodiment. For example, rubber may be used in place of the compression coil spring 11 as an elastic body. You may.

[0026]

As described above in detail, according to the present invention, the resonance frequency of the vibration system including the mass body and the elastic body is set to be substantially the same as the frequency of the engine vibration at the time of idling. It is possible to generate an amplitude vibration, and to provide an excellent effect that the engine vibration can be effectively reduced over a wide operating range including an idling time.

[Brief description of the drawings]

FIG. 1 is a sectional view of a vehicle engine mount according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a state where an engine is mounted on a vehicle body using the engine mount of one embodiment.

FIG. 3 is a graph showing a relationship between frequency and amplitude of engine vibration in one embodiment.

FIG. 4 is a diagram showing a relationship between acceleration of engine vibration and an ignition signal in one embodiment.

FIG. 5 is a graph showing a relationship between a vibration frequency and a vibration frequency obtained by a movable iron core and a compression coil spring in one embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Car body which comprises a part of transmission path of engine vibration, 3 ... Bracket which comprises a part of transmission path of engine vibration, 9 ... Movable iron core as a mass body, 11 ...
A compression coil spring as an elastic body; 12, an electromagnetic coil constituting a part of the driving means; 14, an amplifier constituting a part of the driving means; 15 a phase shifter constituting a part of the driving means;
6 ... Oscillator forming part of driving means, 17 ... Controller forming part of driving means, ωn ... Resonance frequency

Claims (1)

(57) [Claims] 1. A mass body provided in a transmission path of engine vibration and capable of reciprocating in a transmission direction of the engine vibration, and a mass body provided in the transmission path and expandable and contractable in a transmission direction of the engine vibration. An elastic body; and a driving unit for driving the mass body to forcibly vibrate the mass body and the elastic body, and reducing transmission of the engine vibration by the vibration. An engine vibration reduction device characterized in that the resonance frequency of a vibration system comprising: is set to be substantially the same as the frequency of engine vibration during idling.