JP2021035813A - Hybrid system - Google Patents

Abstract

To provide a hybrid system in which a power control unit can be fastened even without using a dedicated vibration damping member.SOLUTION: A hybrid system 1 includes: an in-line n-cylinder engine 11 which includes a crankshaft, a casing for supporting the crankshaft, and a damper mounted on the crankshaft; and a motor 12 which includes a stator 12a and is directly or indirectly mounted on the casing of the engine 11. In the hybrid system 1, when the natural frequency of the stator 12a is defined as Fs, a smallest order N, among orders which each allow a natural frequency Fd of a unit to be reached at a revolution speed equal to or less than the upper limit revolution speed of the engine 11, and which are each an integral multiple of n/2, satisfies the relationship: Fd×(N±1)/N≠Fs.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hybrid system.

Patent Document 1 describes an electric vehicle in which a power control unit (PCU) is fixed above a housing accommodating a motor and a dynamic damper is attached to the lower surface of the PCU.

JP-A-2017-007553

However, in the technique described in Patent Document 1, a dedicated anti-vibration member is required to reduce the vibration applied to the PCU during normal driving, and the electrical connection member between the PCU and the motor is also soft enough to withstand the vibration. Since it is necessary to use a cable, the number of parts increases and the cost increases.

Therefore, an object of the present invention is to provide a hybrid system capable of fastening a power control unit without using a vibration isolator dedicated to the power control unit.

One aspect of the present invention for achieving the above object includes an in-line n-cylinder engine including a crankshaft, a casing supporting the crankshaft, a damper attached to the crankshaft, and a stator. A hybrid system comprising a motor that is attached directly or indirectly to the casing of the engine. Then, in the hybrid system, when the intrinsic frequency of the unit including the crankshaft and the damper is Fd and the intrinsic frequency of the stator is Fs, the intrinsic frequency of the unit is at a rotation speed equal to or less than the upper limit rotation speed of the engine. It is assumed that the smallest order N among the orders that can reach Fd and is an integral multiple of n / 2 satisfies the relationship of Fd × (N ± 1) / N ≠ Fs.

When the vibration of the crankshaft is reduced by the damper, the resonance of the stator is not excited when the vibration component that excites the strongest resonance at the natural frequency Fd of the unit including the crankshaft and the damper is transmitted to the casing of the engine. The hybrid system according to this aspect satisfies the above-mentioned relationship so as not to excite the resonance of the stator in this way, and thereby the vibration received by the power control unit directly or indirectly installed on the motor side. Is reduced, and it becomes possible to fasten the power control unit without using a vibration isolator. Therefore, according to this aspect, it is possible to fasten the power control unit to the hybrid system without using the vibration isolator dedicated to the power control unit.

According to the present invention, it is possible to provide a hybrid system capable of fastening a power control unit without using a vibration isolator dedicated to the power control unit.

It is an external view which shows one configuration example of the hybrid system which concerns on embodiment. It is an external view which shows an example of the crankshaft provided in the hybrid system of FIG. It is a figure which shows the stator part of the motor in the hybrid system of FIG. It is a figure which shows the example of the rotation order. It is a figure which shows the example of the rotation order and the magnitude of a forcing force. It is a figure which shows the example of the rotation order in the case of Nmax = 6000 rpm. It is a figure which shows an example of the explosion timing of each cylinder. It is a figure which shows the result of having performed the frequency analysis about one cylinder in FIG. 7. It is a figure which shows the phase relationship between an explosion and each degree component with respect to one cylinder in FIG. 7. It is a figure which shows the phase relationship between the explosion and the 0.5th order component of rotation with respect to the cylinders # 1 to # 4 in FIG. It is a figure which shows the phase relationship of the component of rotation 0.5th order, 1st order, 1.5th order, 2nd order, ... With respect to cylinders # 1 to # 4 in FIG. It is a perspective view which shows the example of the input direction of the explosive force to the crank in the crankshaft of FIG. FIG. 12 is a view seen from a direction perpendicular to the crankshaft. It is a figure which shows the phase relationship between the explosion and the 0.5th order component of rotation in consideration of the input of the explosive force with respect to the cylinders # 1 to # 4 in FIG. FIG. 7 is a diagram showing the phase relationship of the components of rotation 0.5th order, primary order, 1.5th order, secondary order, ... When the input of explosive force is taken into consideration for the cylinders # 1 to # 4 in FIG. Is. It is a figure for demonstrating the vibration of a round bar supported by a bearing. It is a figure for demonstrating the rotation and vibration of the round bar of FIG. It is a figure for demonstrating ± 1st order transformation. It is a figure which shows the example of the frequency when the crank resonance is input to a casing. It is a figure for demonstrating the twist mode of a crankshaft body and the mode after adding a pulley damper. It is a figure which shows the example of the resonance of a crankshaft body and the resonance after adding a dynamic damper.

Hereinafter, the present invention will be described through embodiments of the invention, but the invention according to the claims is not limited to the following embodiments. Moreover, not all of the configurations described in the embodiments are indispensable as means for solving the problem. Hereinafter, embodiments will be described with reference to the drawings.

(Embodiment)
This embodiment will be described with reference to FIGS. 1 to 21. FIG. 1 is an external view showing a configuration example of a hybrid system according to the present embodiment. FIG. 2 is an external view showing an example of a crankshaft provided in the hybrid system of FIG. 1, and FIG. 3 is a view showing a stator portion of a motor in the hybrid system of FIG.

As shown in FIG. 1, the hybrid system 1 according to the present embodiment can include a power control unit (PCU: Power Control Unit) 10, an engine (engine block) 11, and a motor (motor block) 12. The hybrid system 1 can be a system mounted on a vehicle such as a hybrid vehicle capable of hybrid driving by the engine 11 and the motor 12.

The PCU 10 is a unit that controls electric power to a motor, and can be composed of, for example, an inverter that drives the motor 12, a boost converter that controls a voltage, and a DC / DC converter that steps down a high voltage. A transaxle can be built in the block of the motor 12, and the PCU 10 can be fastened to the transaxle. The PCU 10 is generally arranged on the upper part of the motor 12, but is not limited to this as long as it is directly or indirectly installed (arranged) on the motor 12 side instead of the engine 11 side. .. The configuration and shape of the PCU 10 are not limited.

The engine 11 is an in-line n-cylinder engine including a crankshaft 11a as illustrated in FIG. 2, a casing that supports the crankshaft 11a, and a damper attached to the crankshaft 11a. As long as the engine 11 has such a configuration, its shape and the presence or absence of additional elements do not matter. FIG. 2 illustrates a 4-cylinder crankshaft 11a including a first (# 1) cylinder, a second (# 2) cylinder, a third (# 3) cylinder, and a fourth (# 4) cylinder. Then, according to this example, an example of n = 4 will be described, but the present invention is not limited to this, and the same applies to other cylinders such as 3 cylinders. In the following, for example, the # 1 cylinder may be simply referred to as "# 1" and the like.

Examples of the damper include dampers such as the pulley damper 11b illustrated in FIG. Hereinafter, the pulley damper 11b will be described as an example of the damper, but the damper is not limited to this. The pulley damper 11b is attached to one end of the crankshaft 11a and functions as a dynamic damper to reduce vibration. A flywheel 11c is attached to the other end of the crankshaft 11a.

The motor 12 includes the stator 12a and is directly or indirectly attached to the casing of the engine 11. As long as the motor 12 has such a configuration, the shape, the presence or absence of additional elements, the arrangement position with respect to the engine 11, and the like do not matter. In FIG. 1, the stator of the motor generator is mentioned as the stator 12a, but the present invention is not limited to this.

In the hybrid system 1 as described above, as shown by the white arrow in FIG. 2, the fourth (# 4) journal portion is swayed in the direction perpendicular to the plane (the direction indicated by the thick line single arrow in FIG. 1). This is caused by the torsional resonance in the crankshaft 11a, as shown by the double-headed arrow in FIG.

Further, in the hybrid system 1 as described above, the stator 12a is also shaken in the directions indicated by the thick double-headed arrow in FIG. 1 and the double-headed arrow in FIG. Then, the fourth journal portion and the stator 12a resonate to swing the PCU 10 in the direction of the thick double-headed arrow in FIG. 1, and if no measures are taken, the PCU 10 may be damaged.

That is, in the hybrid system 1 including the engine 11, the motor 12, and the PCU 10, the engine 11 (engine block) vibrates due to the torsional resonance of the crank, and is amplified by the resonance of the stator 12a of the motor 12, and the PCU 10 vibrates and is damaged. A phenomenon can occur. This phenomenon may be avoided by mounting the anti-vibration structure on the PCU 10.

However, the present embodiment attempts to avoid the above phenomenon by focusing on the engine rotation order and dispersing the resonance due to the PCU breakage due to the resonance on the crank side even if such a vibration isolation structure is not mounted. It is a thing.

In the present embodiment, how to disperse the resonance will be specifically described below. In the following, the natural frequency of the unit including the crankshaft 11a and the pulley damper 11b will be Fd, and the natural frequency of the stator 12a will be Fs.

The hybrid system 1 according to the present embodiment defines the vibration components of each order obtained by Fourier transforming the vibration waveform of the torque input from one cylinder of the engine 11 to the crankshaft 11a in order to disperse the resonance. To do.

Here, the order of the vibration component is defined as the number of times the component vibrates in one rotation of the crankshaft 11a. For example, the order of the component that vibrates four times per rotation is the fourth order. Further, since the engine 11 is an in-line n-cylinder engine such as an in-line 4-cylinder engine, the waveforms of the torque input from each cylinder to the crankshaft 11a are theoretically the same, and only the phases are out of phase. Then, when the torque waveform is Fourier transformed, waveforms of vibration components of different orders can be obtained.

Of the vibration components thus obtained, a component that is an integral multiple of n / 2 tends to excite the resonance of the crankshaft 11a. Further, the lower the order, the stronger the vibration energy, so that the component of the smallest order N whose order is an integral multiple of n / 2 excites the strongest resonance.

Further, since the order represents the number of vibrations in one rotation as described above, the frequency of the vibration component of each order increases as the number of rotations of the engine 11 increases (frequency F = (rotation speed Ne [rpm] / 60). [Seconds]) x order).

Therefore, the component that can actually excite the resonance is limited to the component that can reach the natural frequency Fd of the unit at a rotation speed equal to or less than the upper limit rotation speed of the engine 11. In other words, the order that can actually excite the resonance is limited to the order that can reach the natural frequency Fd of the unit at a rotation speed equal to or less than the upper limit rotation speed of the engine 11.

In the hybrid system 1 according to the present embodiment, the strongest resonance is excited at the natural frequency Fd of the unit by defining the relationship between the natural frequencies Fd and Fs so as to avoid such a vibration component that easily excites the resonance. When the vibrating component is transmitted to the casing of the engine 11, the resonance of the stator 12a is prevented from being excited.

Specifically, the hybrid system 1 according to the present embodiment has the smallest order among the orders that can reach the natural frequency Fd of the unit at a rotation speed equal to or less than the upper limit rotation speed of the engine 11 and is an integral multiple of n / 2. It is assumed that the order N satisfies the relationship of Fd × (N ± 1) / N ≠ Fs. For example, the hybrid system 1 can reach the natural frequency Fd of the unit at a rotation speed equal to or less than the upper limit rotation speed of the engine 11 among the orders indicating the vibration components obtained as described above, and is an integral multiple of n / 2. It is assumed that the smallest order N among the orders is satisfying the relationship of Fd × (N ± 1) / N ≠ Fs. By designing to satisfy such a relationship, the resonance of the stator 12a is not excited when the vibration component that excites the strongest resonance at the natural frequency Fd of the unit is transmitted to the casing of the engine 11. , Vibration to the PCU 10 can be suppressed.

First, this relationship will be briefly described with reference to FIGS. 4 to 6. FIG. 4 is a diagram showing an example of the rotation order, FIG. 5 is a diagram showing an example of the rotation order and the magnitude of the forced force, and FIG. 6 is a diagram showing an example of the rotation order when Nmax = 6000 rpm.

FIG. 4 illustrates the even-numbered orders (2, 4, 6, 8, 10, ...) In the relationship between the engine speed (Eng speed) and the frequency. Here, the frequency of the Na order in the Eng rotation speed Ne is (Ne / 60) × Na as described above. The downward arrow in FIG. 4 indicates the frequency at Nmax of each even order. As a result, in the used region (0 to Nmax) of the engine 11, the frequency range of the lowest even-numbered order can be known. For example, as shown in FIG. 6, at Nmax = 6000 rpm, the frequencies of each even order at Nmax are 200 Hz for the second order, 400 Hz for the fourth order, 600 Hz for the sixth order, and the like. Further, as shown in FIG. 5, the level of the forcing force (explosion forcing force) decreases as the rotation order becomes higher.

Therefore, in relation to FIG. 6, for example, when the resonance (also referred to as crank resonance) of the unit is 500 Hz, the lowest order (that is, the order with the largest forcing force) input to the crank is the sixth order.

Then, in the present embodiment, the natural frequency Fd of the unit is raised or lowered with respect to the even-numbered order for exciting the twist mode of the crankshaft 11a. The natural frequency Fd is the resonance frequency of the unit in which the pulley damper 11b is connected to the crankshaft 11a, and is the resonance frequency on the crank side. Therefore, it can also be referred to as the crank resonance frequency. For the same reason, the resonance of the unit is also referred to as crank resonance.

Specifically, in the present embodiment, the crank resonance frequency (N ± 1) / N is multiplied by the smallest order N (the order N having the largest forcing force) among the even orders that excite the resonance on the crank side. The natural frequency Fd) and the resonance frequency Fs of the stator 12a are dispersed. Due to such dispersion, when the vibration component that excites the strongest resonance at the natural frequency Fd of the unit is transmitted to the casing of the engine 11, the resonance of the stator 12a is not excited, so that the vibration to the PCU 10 is suppressed. be able to.

In order to more specifically explain the effect of the present embodiment, the reasons for the individual conditions will be described below.

First, in the present embodiment, the rotation order is limited to even-numbered orders (orders 2, 4, 6, 8, ... In the example of four cylinders) because it is the order that excites the torsional resonance of the crank. Because there is. The reason why the even order excites the torsional resonance of the crank will be described below.

For that purpose, first, the phase relationship between the explosion and each order component will be described with reference to FIGS. 7 to 11. FIG. 7 is a diagram showing an example of the explosion timing of each cylinder, and FIG. 8 is a diagram showing the result of frequency analysis for one cylinder in FIG. 7. FIG. 9 is a diagram showing the phase relationship between the explosion and each order component with respect to one cylinder in FIG. 7, and FIG. 10 shows the explosion and the 0.5th order component of rotation with respect to the cylinders # 1 to # 4 in FIG. It is a figure which shows the phase relation. FIG. 11 is a diagram showing the phase relationship of the components of the rotation 0.5th order, the primary order, the 1.5th order, the secondary order, ... With respect to the cylinders # 1 to # 4 in FIG.

FIG. 7 shows the time-axis waveforms related to the explosion of the # 1 to # 4 cylinders. Focusing on one cylinder, an explosion occurs once every two rotations of the crank, and as shown by the arrow in FIG. 7, the explosion is repeated in the order of # 1 → # 3 → # 4 → # 2.

When the frequency analysis is executed for this one cylinder, it becomes as shown in FIG. 8, and when the DC component (0 Hz component) is excluded, the 0.5th order component of rotation is the largest. This is because it explodes once every two rotations, and its higher-order components such as primary, 1.5-order, secondary, and so on appear, but gradually as the order becomes higher. The level drops. For example, at 6000 rpm, when divided by 60, the number of revolutions per second is 100 rps, and from one explosion in two revolutions, 100 rpm ÷ 2 = 50 times (explosion / s), which is the number of explosions per second. Further, the reciprocal of 50 times (explosion / s) is 0.02 (s / explosion), and the time required for one explosion can be obtained. When this time axis graph is frequency-analyzed (FFT), the 0.5th order is 50Hz, the 1st order is 100Hz, the 1.5th order is 150Hz, the 2nd order is 200Hz, and so on, and the level of this frequency becomes large. ..

Next, what kind of phase relationship each order component (0.5, 1, 1.5, 2, ...) Has with the time axis graph of the explosion will be described. First, the phase relationship of each order component in one cylinder will be described. As shown in FIG. 9, in one cylinder, the timing of the peak of the graph showing each order component coincides with the peak of the graph showing the explosion timing.

Focusing on one order component (here, the 0.5th order component), the phase relationship between the explosion and the 0.5th order component of rotation in the # 1 to # 4 cylinders is as shown in FIG.

Based on the same idea, the phase relationship of the time axis of 0.5th order, 1st order, 1.5th order, 2nd order, ... Is shown in FIG. Here, in the 0.5th order, the phases of # 1 to # 4 are shifted by 90 °, and the order of peaking is in the order of # 1 → # 3 → # 4 → # 2. Further, in the first order, the phases of # 1 and # 4, and # 2 and # 3 are the same, and the two phases are 180 ° out of phase. Further, in the 1.5th order, the phases of # 1 to # 4 are shifted by 90 °, and the order of peaking is in the order of # 1 → # 2 → # 4 → # 3. Moreover, in the secondary, all of # 1, # 2, # 3, and # 4 are in-phase.

The 2.5th order has the same phase as the 0.5th order, the 3rd order has the 1st order, the 3.5th order has the 1.5th order, and the 4th order has the 2nd order. Therefore, the phase relationship of each order component in the # 1 to # 4 cylinders is 4 patterns of 0.5 + 2m order, 1 + 2m order, 1.5 + 2m order, 2 + 2m order (m = 0, 1, 2, 3, ...). are categorized.

Next, with reference to FIGS. 12 to 15, what kind of pattern the phase relationship of each order component is classified into will be described in consideration of the input of the explosive force to the crankshaft 11a. FIG. 12 is a perspective view showing an example of the direction in which the explosive force of the crankshaft 11a of FIG. 2 is input to the crank, and FIG. 13 is a view of FIG. 12 viewed from a direction perpendicular to the crankshaft. FIG. 14 is a diagram showing the phase relationship between the explosion and the 0.5th-order component of rotation when the input of the explosive force is taken into consideration for the cylinders # 1 to # 4 in FIG. 7. FIG. 15 shows the phases of the components of the rotation 0.5th order, 1st order, 1.5th order, 2nd order, ... When the input of the explosive force is taken into consideration for the cylinders # 1 to # 4 in FIG. It is a figure which shows the relationship.

The crankshaft 11a is rotating, and as shown in FIGS. 12 and 13, the input of force is maximized in the direction of the crank angle θ and the connecting rod inclination φ where the in-cylinder pressure is maximized. Here, assuming that the crank is in a stationary state, the direction of the force due to the explosion of the # 1 to # 4 cylinders is the direction indicated by the arrow in FIGS. 12 and 13. If the direction of the force for the # 2 and # 3 cylinders is positive, the force for the # 1 and # 4 cylinders will be in the negative direction.

Therefore, when the input of the explosive force to the crankshaft 11a is taken into consideration, the in-cylinder pressure on the time axis has a phase relationship as shown in FIG. 14 in which the positive and negative are reversed for # 1 and # 4 in the phase relationship of FIG. .. Regarding the phase relationship of FIG. 10, if the same process as that of the previous page is performed in the same procedure as when the phase relationship of FIG. 11 is obtained, the rotation is 0.5th order, 1st order, 1st order when the input of explosive force is considered. The phase relationship of the components of the fifth order, the second order, ... Is shown in FIG.

That is, in the 0.5th order, the phases of # 1 to # 4 are shifted by 90 °, and the order of peaking is in the order of # 1 → # 2 → # 4 → # 3 (referred to as pattern A). .. Further, in the primary, all of # 1, # 2, # 3, and # 4 are in phase (referred to as pattern B). Further, in the 1.5th order, the phases of # 1 to # 4 are shifted by 90 °, and the order of peaking is in the order of # 1 → # 3 → # 4 → # 2 (referred to as pattern C). .. Further, in the second order, the phases of # 1 and # 4 are the same, the phases of # 2 and # 3 are the same, and the two phases are 180 ° out of phase (referred to as pattern D).

Up to this point, it has been explained that the input phase of the explosive force for the # 1 to # 4 cylinders changes depending on the rotation order.

Next, it will be described that the rotation order that most excites the torsional resonance of the crankshaft 11a described with reference to FIG. 2 is the pattern D.

In the torsional resonance described with reference to FIG. 2, since the rotational inertia of the flywheel 11c is large, the rotational inertia of # 1 to # 3 and the rotational inertia of the flywheel 11c distort the vicinity of the pins of the # 4 cylinder, and # 1 to # This is a deformation mode in which the pin 3 rotates. That is, the pins # 1 to # 3 are the antinodes of the mode, and are the places where this mode is easily excited. As shown by the length of the double-headed arrow in FIG. 2, the amount of movement is large in the order of # 1> # 2> # 3, and the order in which they are easily excited is also # 1> # 2> # 3. It will be in order.

Each of patterns A to D will be examined.
In pattern A and pattern C, # 2 and # 3 have an opposite phase relationship and cancel each other, so that this mode is excited only by the input by # 1. In pattern B, # 1 and # 2 cancel each other. The phases of the inputs are in phase, but # 1 and # 2 are because the input positions are symmetrical with respect to the center of rotation. It is excited by # 3, but since # 3 is close to the node # 4, it is difficult for the mode to be excited. On the other hand, the pattern D (even order) is an input pattern in which the twist is most excited because # 1 to # 3 are not canceled at all.
The above is the relationship between the forcing force and the crank resonance.

Hereinafter, the dispersion between the crank resonance and the resonance of the stator 12a (stator resonance) will be described with reference to FIGS. 16 to 19.

First, the degree conversion will be described with reference to FIGS. 2 and 16 to 18. FIG. 16 is a diagram for explaining the vibration of the round bar supported by the bearing, and FIG. 17 is a diagram for explaining the rotation and vibration of the round bar of FIG. Note that FIG. 17 shows a cross section in a direction perpendicular to the length direction of the round bar of FIG. FIG. 18 is a diagram for explaining ± primary transformation.

The crankshaft 11a vibrates while rotating in a mode as described with reference to FIG. 2 (shaking the # 4 journal portion while twisting), and transmits the vibration to the block of the engine 11. When a force is input from a rotating and vibrating object to a stationary object such as a case via a bearing or the like, a degree transformation called "± primary transformation" occurs. This degree conversion will be briefly described with reference to FIGS. 16 to 18.

For example, consider a case where a round bar 23 is supported by a bearing 22 and vibrates while rotating, as in the structure 20 shown in FIG. Here, an example of vibrating 5 times in 1 second and rotating 1 time in 1 second will be described. When the vibration pick is attached to the round bar 23 and the measurement is performed, the waveform is as shown in FIG. 18I. On the other hand, when the vibration pick is attached to the case 21 to which the bearing 22 is attached and the X direction is measured, the waveform is as shown in III of FIG. This is because, as in the round bars 23a, 23b, 23c, 23d in FIG. 17, when the round bar 23 rotates while vibrating, the component in the X direction is a cos waveform (due to rotation) as shown in II of FIG. This is because it is a component obtained by multiplying (1 Hz waveform). Next, when the waveform as shown in III of FIG. 18 is analyzed, it is formed by adding 4 Hz and 6 Hz (IV + V).

This means that when the vibration waveform shown in I of a rotating object is observed with a stationary object, it is divided into two frequency components, and mathematically speaking, it means the addition theorem of the following equation. Note that n in the following equation has nothing to do with n in the number of cylinders.
sin (nθ) × cosθ = 1/2 {sin (n + 1) θ + sin (n-1) θ}

Next, the dispersion between the crank resonance and the stator resonance will be described with reference to FIG. FIG. 19 is a diagram showing an example of the frequency when the crank resonance is input to the case (casing supporting the crankshaft 11a) and is input to the crankshaft 11a, and is a diagram corresponding to FIG. 4.

Such a variance can be realized by satisfying the above-mentioned relation Fd × (N ± 1) / N ≠ Fs for the smallest order N. For example, when the crank resonance frequency is 500 Hz, the lowest order among the even orders considering the upper limit rotation speed of the engine 11 is the sixth order, and the frequency after ± 1st order conversion is 500 Hz × 5. Next ÷ 6th order = 416Hz, 500Hz × 7th order ÷ 6th order = 583Hz. When any of these frequencies overlaps with the frequency of the torsional resonance of the stator 12a, the resonance is amplified, so that the stator resonance frequency is shifted from 416 Hz and 583 Hz (different from 416 Hz and 583 Hz). It is excited even at higher orders such as 8th order, 10th order, and so on, but as described above, since the coercion force of the lower order is a larger value, the input by the lower order is preferentially avoided. Therefore, the stator resonance frequency may be the same as, for example, the frequency after ± 1st order conversion for the 8th order (500 Hz × 8th order ÷ 9th order = 444 Hz, or 500 Hz × 8th order ÷ 7th order = 571 Hz).

Next, an example of a method of changing the crank resonance (a method of changing the crank resonance frequency) will be described with reference to FIGS. 20 and 21. FIG. 20 is a diagram for explaining a twist mode of the crankshaft 11a main body and a mode after adding the pulley damper 11b. Note that FIG. 20 shows the torsional resonance of the crank body (main body of the crankshaft 11a), the mode after adding the pulley damper 11b (mode Ma), and the mode after adding the pulley damper 11b (mode Mb). The case where the direction of shaking in the upper and lower stages is opposite is shown. Further, FIG. 21 is a diagram showing an example of resonance of the crankshaft main body and resonance after adding a dynamic damper.

Explaining the torsional resonance of the crankshaft 11a, in the cranks used in recent years, the torsional resonance is reduced by using the pulley damper as a dynamic damper to reduce the vibration. Specifically, the torsional resonance causes an abnormal noise of "crank striking sound", and as a countermeasure, the pulley damper is used as a dynamic damper to reduce the vibration. However, when a dynamic damper is used, a phenomenon occurs in which there are two new types of crank resonance as described below.

First, in FIG. 20, as shown by the crankshafts 11aa and 11ab, the torsional resonance of the main body of the crankshaft 11a is indicated by an arrow, and the distortion occurrence location is in the vicinity of pin # 4. In FIG. 20, as shown by the crankshafts 11ac and 11ad, in the mode Ma after the pulley damper 11b is added, the crankshaft 11a and the pulley damper 11b are in phase with each other. On the other hand, in FIG. 20, as shown by the crankshafts 11ae and 11af, in the mode Mb after the pulley damper 11b is added, the crankshaft 11a and the pulley damper 11b are in opposite phases.

In this way, in order to change the frequencies of the two resonances newly generated by the addition of the pulley damper 11b (mode Mb in which the pulley damper is in phase with respect to the crankshaft and mode Mb in which the pulley damper is in phase with respect to the crankshaft), the torsional resonance of the crankshaft 11a body is performed. It can be realized by changing (for example, changing the spring or mass centering). Alternatively, in order to change such a frequency, it can be realized by changing the torsional resonance of the pulley damper 11b.

Resonance will be described with reference to FIG. 21 by taking as an example the case where the vicinity of the first journal portion is vibrated in the twisting direction and the response is taken in the twisting direction. When the torsional resonance of the crankshaft 11a body is at a certain frequency (left figure in FIG. 21), adding a pulley damper 11b as a dynamic damper results in two peaks (right figure in FIG. 21). The two peaks in the right figure of FIG. 21 are determined by the torsional resonance of the main body of the crankshaft 11a in the left figure of FIG. 21 and the resonance of the pulley damper 11b in the right figure of FIG. 21. Taking these into consideration, the crank resonance can be changed.

In the above, the present embodiment has been described by taking as an example an engine that explodes in the order of # 1 → # 3 → # 4 → # 2 in the case of four cylinders, but n is not limited to 4 as described above. For example, an engine that explodes in the order of # 1 → # 2 → # 3 with 3 cylinders has 3 types of patterns, and it is the rotation 1.5th order, 3rd order, 4.5th order that excites the crank torsion resonance. 6th order, ..., 1.5m order (m = 1, 2, 3, ...). Therefore, in the case of 3 cylinders, the upper limit of the engine speed is considered in the same way as in the case of 4 cylinders, and it is the most among 1.5th, 3rd, 4.5th, 6th, and so on. It can be said that damage to the PCU 10 can be avoided by designing so as to satisfy the relationship of Fd × (N ± 1) / N ≠ Fs for a small order N.

In the present embodiment described above, the smallest order N is defined, but the relationship of Fd × (M ± 1) / N ≠ Fs also applies to the order larger than the smallest order N (referred to as M). It is desirable to meet. However, as described above, it is possible to avoid damage to the PCU 10 by designing so as to satisfy the relationship of Fd × (N ± 1) / N ≠ Fs for the smallest order N in which resonance is excited most. I can say.

As described above, according to the hybrid system 1 according to the present embodiment, it is possible to fasten the PCU 10 without using a vibration isolator dedicated to the PCU 10 such as rubber or a dynamic damper. Therefore, in the present embodiment, it is not necessary to provide a cable between the motor 12 and the PCU 10, and the cost of the dedicated anti-vibration member is not required, so that the cost can be reduced. Further, in the present embodiment, the support structure when the dedicated anti-vibration member is used can prevent a phenomenon in which excessive acceleration is input to the PCU 10 and the PCU 10 is damaged.

1 Hybrid system 11 engine (engine block)
12 motor (motor block)
12a Stator 10 Power control unit (PCU)
11a Crankshaft 11b Pulley damper 11c Flywheel 20 Structure 21 Case 22 Bearing 23 Round bar

Claims (1)

An in-line n-cylinder engine including a crankshaft, a casing that supports the crankshaft, and a damper attached to the crankshaft.
A motor that includes a stator and is attached directly or indirectly to the casing of the engine.
With
When the natural frequency of the unit including the crankshaft and the damper is Fd and the natural frequency of the stator is Fs,
The smallest order N among the orders that can reach the natural frequency Fd of the unit at a rotation speed equal to or less than the upper limit rotation speed of the engine and is an integral multiple of n / 2 is Fd × (N ± 1) / N ≠ Fs. Satisfy the relationship,
Hybrid system.

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