JPH02306825A - Power transmission device of automobile - Google Patents

Abstract

PURPOSE:To reduce a noise accompanied by rotation fluctuation by making a torsional quarternary mode resonance frequency determined by a specified scheme lower than a frequency corresponding to the idling engine speed of an internal combustion engine. CONSTITUTION:Between an internal combustion engine and a wheel, a power transmission device containing a clutch device 2, a change-gear device 3 having a change gear ratio xsi, a propeller shaft 4, a center brake device 5, a final reduction gear 6 having a final reduction gear ratio eta and an accelerator shaft connecting the device 6 to the wheel is symmetrically disposed. In this case, a torsional quarternary mode resonance frequency (f) determined by a scheme (I) is less than a frequency f0 corresponding to the idling engine speed of the internal combustion engine. In the scheme, I1 is the sum of inertia moments of rotating elements of the devices 2, 3, I2 is the sum of inertia moments of rotating elements of the propeller shaft 4 and the center brake device 5, I3 is the sum of inertia moments of rotating elements of the gear 6, each of K1, K2 is a torsional spring constant of each spring element of the accelerator shaft, and pi is the ratio of the circumference of a circle to its diameter. Then, the frequency (f) is never caused in practical driving area.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of M Tojo) This invention relates to a power transmission device for a motor vehicle such as a truck.

(Prior art and problems to be solved) As shown in Figure 1, the power transmission device installed between the internal combustion engine and the wheels of automobiles such as trucks is attached to the output shaft of the engine (ENG). A clutch device 2 that frictionally engages with the flywheel 1 and connects/disconnects power transmission, a transmission gear device (T/M) 3 having, for example, five forward speeds and two reverse speeds, and a propeller connected to this output shaft. A center brake device 5 that is attached to the shaft 4, the propeller shaft 4, or the output side of the speed change gear device 3 (in the illustrated example, it is attached to the output side of the speed change gear device 3), and has a center brake drum, and the propeller shaft 4. It is configured to include a final reduction gear 6 connected to the other end, an axle shaft (not shown) connecting the final reduction gear 6 and the wheels, and the like.

A conventional power transmission device configured in this manner is shown in FIG. 2 and can be represented simply as a vibration model. What is shown in FIG. 2 is a torsional fourth-order mode vibration system, and the reference numeral 1. are rotating elements of the clutch device 2 and transmission gear device 3, such as the clutch hub 2 and the transmission gear. Similarly, the symbol 2 represents the sum of the moments of inertia of the drive pinion, etc., the rotating elements of the propeller shaft 4 and the center brake device 5, such as the propeller shaft main body,
Represents the sum of the moment of inertia of the center brake drum, etc.
The symbol ■ represents the sum of the moments of inertia of the rotating elements of the final reduction gear 6, such as the differential gear, the ring gear, and the differential case.

kl represents the tear spring constant of the spring element in the clutch device 2, and k□ represents the torsional spring constant of the spring element of the axle shaft, for example, the axle shaft body. The broken line indicates the magnitude of rotational fluctuation due to the fourth-order mode.

In conventional automobile power transmission systems, the resonance point of this vibration mode is at the engine speed N, as shown by the broken line in Figure 4.
e exists in the practical range (rotation range above normal idle rotation), and as a result, rotational fluctuations of the differential gear, propeller shaft, etc. near the resonance point become large (dashed line in Figure 5).
The noise inside the car (muffled sound) was high when driving at low speeds.

In addition, FIG. 4 shows the rotational fluctuation (unit: rpm) of the differential gear of the final reduction gear 6, and from the torsional fourth-order vibration mode shown in FIG. It will be understood that the same trend is shown in the figure.

The present invention was made in order to solve these problems, and it suppresses rotational fluctuations due to the torsional fourth vibration mode in the practical range of rotational speed of an internal combustion engine, and reduces noise accompanying this rotational fluctuation. The purpose of the present invention is to provide a power transmission device for an automobile that achieves the following.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides at least a clutch device that connects and disconnects power transmission between an internal combustion engine and wheels, and a speed change gear having a speed ratio ξ. a propeller shaft, one end of which is connected to the output shaft of the transmission gear;
A center brake device attached to the propeller shaft or the output shaft of the speed change gear device, a final reduction device connected to the other end of the propeller shaft and having a final reduction ratio η, and a connection between the final reduction device and the wheels. In a power transmission device including an axle shaft, here,
r is the resonance frequency of the torsional fourth mode of the power transmission device, 1
1 is the sum of the moments of inertia of the rotating elements of the clutch device and the speed change gear device, I2 is the sum of the moments of inertia of the rotating elements of the propeller shaft and center brake drum, and ■ is the moment of inertia of the rotating elements of the final reduction gear. Sum, k, and □ are torsional spring constants of each spring element of the clutch device and axle shaft, respectively, π is pi, and the torsional fourth mode resonance frequency r determined by the above formula is the internal combustion There is provided a power transmission device for an automobile characterized in that the frequency is less than or equal to the frequency f0 corresponding to the idle rotation speed of the engine.

The sum of the moments of inertia of the rotating elements of the clutch device and transmission gear device included in the automobile power transmission device of the present invention!
, are set so that the following equation holds.

Further, the sum 12 of the moments of inertia of the rotating elements of the propeller shaft and the center brake device is set so that the following equation is established.

Torsional spring constant k of the spring element of the clamping device.

is the following formula is set so that it holds true.

The torsional spring constant of the spring element of the axle shaft is
The following equation is set so that it holds true.

And the sum of the moments of inertia of the rotating elements of the final reduction gear!
, are set so that the following formula % formula % holds true.

(Operation) When the moment of inertia of each rotating element and the spring constant of the spring element are set so that the above formulas hold, the resonant vibration frequency f of the fourth-order torsional mode of the power transmission device corresponds to the idle rotation speed. Since the rotational speed in the region below the idle rotational speed is outside the practical range of engine operation, resonant vibration in the fourth-order torsional mode does not occur in the practical range of engine operation.

(Example) An example of the present invention will be described in detail below based on the drawings. Note that the first component of an automobile power transmission system is
This is the same as shown in the figure, but in the present invention, the vibration model, the moment of inertia of the rotating element of each component, and the setting of the spring constant of the spring element are different. Therefore,
The configuration of the power transmission device shown in FIG. 1 is the configuration of the present invention, and description of its individual elements will be omitted.

As a result of various studies on torsional vibration models of automobile power transmission devices, the present invention has discovered that when the resonance frequency r of the fourth-order torsional mode is calculated using the model shown in FIG. 3, the calculated resonance frequency f is actually The moment of inertia of the rotating element of the automobile's power transmission device and the spring constant of the spring element should be This is based on the knowledge that if the value is set, the fourth-order mode resonance vibration will not occur in the practical operating range of the engine.

The torsional vibration model in Fig. 3 is a conversion of the vibration model in Fig. 2 into a model equivalent to the engine shaft based on the above-mentioned knowledge. In this model, ■ is the equivalent moment of inertia to the engine shaft, k is the equivalent torsional spring constant of the axle shaft to the engine axis. Here, the equivalent moment of inertia I and the equivalent torsional spring constant are expressed by the following formula (+1. (2
) is obtained by ■−L+I□/ξ”10+s/(ξ・η
)2...(1) k=! /(ξ・7 houses
...(2) Moment of inertia ■1 is the sum of the moments of inertia of the rotating elements of the clutch device 2 and the transmission gear device 3, and to simplify the calculation, the main rotating elements, such as the clutch hub, transmission gear, and drive pinion, are etc. may be taken into consideration and the others may be omitted.

The moment of inertia 1□ is the sum of the moments of inertia of the rotating elements of the propeller shaft 4 and the center brake device 50, and in this case, only the main rotating elements such as the propeller shaft body, center brake drum, etc. are taken into consideration, and the others are omitted. Moment of inertia! , is the sum of the moments of inertia of the rotating elements of the final reduction gear 6, and a differential gear, a ring gear, a differential case, etc. may be considered as the main rotating elements.

The spring constant 1 is the torsion spring constant of the spring element of the clutch device 2, for example, the crank disk, and the spring constant 8
is the torsional spring constant of the axle shaft itself. Further, ξ is the gear ratio of the selected gear position of the transmission gear bag T13, and η is the final reduction ratio of the final reduction gear device 6.

From this equivalent model, the frequency r of the fourth-order backward mode can be easily calculated using the following equation (3).

If the lower limit of the regular rotation speed of the engine (E/G) is, for example, the idle rotation speed N0, then a value smaller than the frequency f0 corresponding to this idle rotation speed N, that is, ``<fo...(4) holds true. If we set the moment of inertia of each rotating element of the power transmission device and the torsional spring constant of each spring element, we get
The resonance frequency f of the fourth-order torsional mode is outside the practical operating range (a rotational range above the practical rotational speed, in this example, above the idle rotational speed), and reduces interior noise within the vehicle (so-called muffled sound) within the practical operating range. be able to. Note that the present invention is applied to a 4-cylinder 4-cycle engine, and the idle rotation speed is N.

For example, if it is 600 rpm, two explosions occur per crankshaft rotation, so the frequency f corresponding to this idle rotation speed N corresponds to 2082.

The solid line in Figure 4 shows an example of the rotational fluctuation of the power transmission device set in this way (rotational fluctuation of the differential pinion), and the solid line in Figure 5 shows the noise level inside the vehicle.From these drawings, the practical operating range ( Engine speed N0 corresponding to frequency f0
It can be seen that the rotational fluctuations and in-vehicle noise in the above driving range are significantly smaller than in the conventional case (indicated by the broken line).

From the above formulas (3) and (4), the clutch device 2
and the sum of the moments of inertia of the rotating elements of the speed change gear device 3 1. may be set to a sufficiently large value so that the following equation (5) holds true.

(5) Similarly, the sum of the moments of inertia of the rotating elements of the propeller shaft 4 and the center brake device 5 (2) is expressed by the following formula (6)
What is necessary is to set it to a sufficiently large value so that the following holds true.

The torsional spring constant kl of the spring element of the Kura-7chi device 2 is:
It is sufficient to set the value to a sufficiently small value so that the following equation (7) holds true.

...(7) The torsional spring constant of the two spring elements of the axle shaft is:
The value may be set to a sufficiently small value so that the following equation (8) holds true.

...(8) The sum l of the moments of inertia of the rotating elements of the final reduction gear 6 is:
It is sufficient to set the value to a sufficiently large value so that the following equation (9) holds true.

(ξη)8 (2πt,)! ξ2 Here, the final reduction ratio η of the final reduction device 6 is a constant value, but the speed ratio ξ of the gear transmission 3 changes in value depending on the selected gear stage. Although it varies depending on the vehicle type, the moment of inertia of each rotating element and the torsional spring constant of the spring element may be set so that each of the above-mentioned equations usually holds true for the gear ratio of the higher gear.

(Effects of the Invention) As detailed above, the automobile power transmission device of the present invention is based on the new knowledge of the vibration model of the torsional fourth mode, (where ■ indicates the clutch device and The sum of the moments of inertia of the rotating elements of the transmission gear system, ■ is the sum of the moments of inertia of the rotating elements of the propeller shaft and the center brake device, ■ is the sum of the moments of inertia of the rotating elements of the final reduction gear, k, and are the torsional spring constants of each spring element of the clutch device and axle shaft, respectively, and π is pi), and the vibration frequency f of the fourth-order torsional mode obtained from the above equation corresponds to the idle speed of the engine. The moment of inertia of each rotating element and the spring constant of the spring element are set so that the frequency f0 is lower than Therefore, the rotational fluctuations of each element are small, and the noise inside the vehicle, especially the noise called muffled noise, can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an automobile power transmission device, FIG. 2 is a diagram showing a conventional torsional fourth-order vibration model of the power transmission device shown in FIG. 1, and FIG. A diagram showing the torsional fourth-order vibration model according to the present invention, FIG. 4 is a graph showing the relationship between the engine rotation speed Ne and the rotation fluctuation of the differential pinion,
FIG. 5 is a graph showing the relationship between the engine speed Ne and the actual insults inside the vehicle. l... flywheel, 2... clutch device, 3...
... Gear transmission (T/M), 4... Propeller shaft, 5... Center brake device, 6... Final reduction device. Applicant Mitsubishi Motors Corporation Agent Patent Attorney Kanji Nagato Figure 1 Figure 2 Figure 3

Claims (6)

[Claims] (1) At least a clutch device that connects and disconnects power transmission between the internal combustion engine and the wheels, a speed change gear device having a speed change ratio ξ, a propeller shaft whose one end is connected to the output shaft of the speed change gear device, and the propeller shaft. or a center brake device attached to the output shaft of the speed change gear device, a final reduction device connected to the other end of the propeller shaft and having a final reduction ratio η, and an axle shaft connecting the final reduction device and the wheels. In the power transmission device comprising: f=(1/2π)√{k_1+k_2/(ξη)^2}
/{I_1+(I_2/ξ^2)+I_3/(ξη)^
2} Here, f is the resonance frequency of the fourth-order torsional mode of the power transmission device, I_1 is the sum of the moments of inertia of the rotating elements of the clutch device and the transmission gear device, and I_2 is the rotation of the propeller shaft and the center brake device. The sum of the moments of inertia of the elements, I_3 is the sum of the moments of inertia of the rotating elements of the final reduction gear, k_1 and k_2 are the torsional spring constants of each spring element of the clutch device and the axle shaft, respectively, and π is the constant of pi. A power transmission system for an automobile, wherein the torsional fourth-order mode resonance frequency f determined by the above equation is less than or equal to the frequency f_0 corresponding to the idle rotation speed of the internal combustion engine. (2) The sum I_1 of the moments of inertia of the rotating elements of the clutch device and the transmission gear device is calculated by the following formula I_1>{k_1+k_2/(ξη)^2}/(2πf
＿0)^2}-(I_2/ξ^2)-I_3/(ξη)
2. The power transmission device for an automobile according to claim 1, wherein the power transmission device is set so that ^2 holds true. (3) The sum I_2 of the moments of inertia of the rotating elements of the propeller shaft and center brake device is calculated by the following formula I_2
/ξ^2>{k_1+k_2/(ξη)^2}/(2π
2. The power transmission device for an automobile according to claim 1, wherein the power transmission device is set so that f_0)^2}-I_1-{I_3/(ξη)^2} holds true. (4) Torsional spring constant k of the spring element of the clutch device
_1 is calculated by the following formula k_1<(2πf_0)^2[I_1+(I_2/ξ_
2) + {I_3/(ξη)^2]-{k_2/(ξη)
2. The power transmission device for an automobile according to claim 1, wherein the power transmission device is set so that ^2} is established. (5) The torsional spring constant k_2 of the spring element of the axle shaft is calculated by the following formula k_2/(ξη)^2<(2πf_0)^2[I_1+
(I_2/ξ_2)+{I_3/(ξη)^2}]-k
2. The power transmission device for an automobile according to claim 1, wherein the power transmission device is set so that _1 holds true. (6) The sum I_3 of the moments of inertia of the rotating elements of the final reduction gear is calculated by the following formula I_3/(ξη)^2>{k_1+k_2/(ξη)^
2}/(2πf_0)^2-I_1-(I_2/ξ_2
2. The power transmission device for a motor vehicle according to claim 1, wherein the power transmission device is set so that the following equation holds true.