JPH045127A - Power transmission device - Google Patents

Abstract

PURPOSE:To make a flywheel compact by disposing belt transmission mechanism between a crankshaft and clutch mechanism, and letting the belt transmission mechanism bear inertial moment required for absorbing rotational torque fluctuation together with the flywheel, that is, the clutch mechanism. CONSTITUTION:A chain case 35 is fitted at the front end part of an internal combustion engine 31, and a clutch housing 37 is fitted at the side part of a cylinder block 32. A transmission case 38 is fitted on the rear end side of the clutch housing 37. Belt transmission mechanism 42, to which the driving force of the engine 31 is directly transmitted, is accommodated in the chain case 35, and clutch mechanism 43 for transmitting torque from the belt transmission mechanism 42 to a transmission 33 is accommodated in the clutch housing 37. The clutch mechanism 43 is provided with a flywheel 51 rigidly secured at an input shaft 48, and a friction clutch 53; and the flywheel 51 is set smaller in diameter than an existing one taking account of inertial moment generated at the belt transmission mechanism 42.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a power transmission system for an internal combustion engine for a four-wheel drive vehicle, for example.

As is well known in the art, front-wheel drive vehicles (FF vehicles) and four-wheel drive vehicles (four-wheel drive vehicles)
As a power plant structure for a WD vehicle, etc., there is a so-called diacosa type power plant structure in which the engine is placed horizontally in the engine room and the transmission is arranged in series with the engine (see Japanese Patent Laid-Open No. 53100535, etc.).

However, in this Giacosa type, the overall length of the power plant is long and the lowest natural frequency is low (so the vibration of the power plant tends to generate muffled noise, especially when the engine rotates at high speeds).

Therefore, as shown in FIGS. 4A and 4B, a transmission 3 is installed on the side of the cylinder block 2 of the engine 1.
Efforts have also been made to attach a transfer 4 to shorten the overall length of the power plant and increase the rigidity of the connection. That is,
A clutch housing 5 is attached to the front of the engine 1,
A chain case 8 is attached to the front end of the clutch housing 5.
are attached to the clutch housing 5, and a transmission case 6 and a transfer case 7 are integrally attached to the side of the clutch housing 5 with the transmission case 6 on top.

The transmission 3 is housed in a transmission case 6, and is arranged side by side on the cylinder block 2 with the main gear train 9a on top and the sub gear train 9b on the bottom. Transfer 4 is front differential 10. It is housed in the transfer case 7 together with the center differential 11, and is disposed on the side of the oil pan 12 at the bottom of the cylinder block 2. The clutch housing 5 has a flange 1
The transmission case 6 and the transfer case 7 are fixed to the front surface of the engine 1 through a flange 14 formed on the side of the cylinder block 2 and the oil pan 12 through a flange 14 provided on the side of the engine 1. It is fixed to the mounting seat 15 with bolts.

A flywheel 17 connected to an end of the crankshaft 16 and a friction clutch 18 are housed within the clutch housing 5. Also, inside the chain case 8, there is an output side chain sprocket 20 provided at the end of the output shaft 19 of the friction clutch 18, and a main gear train 9a.
An input side chain sprocket 22 provided at the end of the main shaft 21 and a drive chain 23 wound between the sprockets 20 and 22 are housed, and the crankshaft 16 is driven via this drive chain 23. The force is transmitted to a transmission member 3 and a transfer 4.

Problems to be Solved by the Invention As described above, in the conventional power transmission device, by attaching the transmission 3 and the transfer 4 to the side of the engine 1, the joint rigidity of the power plant is increased, and the lowest order Although the natural frequency of the engine is lowered and the muffled noise at high speeds can be sufficiently suppressed, the flywheel 17 is directly connected to the crankshaft 16, and fluctuations in the rotational torque of the engine 1 are absorbed only by the inertia of the flywheel 17. Since the power is transmitted to the drive chain 23,
As the flywheel 17 is forced to increase in size,
It becomes difficult for the transmission to smoothly change gears.

That is, the moment of inertia IPI required to smooth the rotation by averaging the rotational torque of the engine 1 depends only on the moment of inertia I2 of the flywheel 17. Therefore, it must be set to a relatively large shape. On the other hand, a predetermined moment of inertia is also generated in the drive chain 23 during rotation, so the transmission 3 has an inertia moment I pr corresponding to the required moment of inertia by the flywheel 17 and a moment of inertia of the drive chain 23. An additional large moment of inertia acts. For this reason, a rotation difference occurs between the drive chain 23 and the crankshaft 16, and they cannot be synchronized with the main shaft 21. As a result, smooth switching of the transmission gears may be hindered.

Means for Solving the Problems The present invention has been devised in view of the above-mentioned conventional problems, and is particularly characterized in that a belt transmission mechanism is disposed between the crankshaft and the clutch mechanism.

Effects According to the present invention having the above configuration, the variation in rotational torque of the crankshaft can be first absorbed by the moment of inertia generated by the belt transmission mechanism, and then further absorbed by the clutch mechanism, so that the required moment of inertia can be shared. The moment of inertia of the flywheel can be made as small as possible. Therefore, the size of the flywheel can be made smaller than before, and the generation of a moment of inertia greater than the required moment of inertia can be prevented.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows a first embodiment in which the power transmission device according to the present invention is applied to a 4WD vehicle, in which 31 is a 4-cylinder internal combustion engine, 32
is the cylinder block, 33 is the transmission, 34
is a transfer, and at the front end of the engine 31,
A chain case 35 is attached with bolts 36. A clutch housing 37 is attached to the side of the cylinder block 32 and is connected to the chain case 35 on the front end side with bolts, and the clutch housing 37 is integrally attached to the side of the cylinder block 32 on the rear end side of the clutch housing 37. A transmission case 38 is attached via a flange 32a provided at the flange 32a. Further, below the transmission case 38, a transfer case 39 is attached by bolts to mounting seats formed on the side surface of the cylinder block 32 and the side surface of the oil pan.

The transmission 33 housed in the transmission case 38 includes a main gear train 33 a and a sub gear train 33 b disposed below the main gear train 33 a. 34 and front differential 40. Center differentials 41 are respectively housed. Furthermore, a belt transmission mechanism 42 to which the driving force of the engine 31 is directly transmitted is housed within the chain case 35, while a rotational force from the belt transmission mechanism 42 is transmitted to the transmission 33 within the clutch housing 37. Clutch mechanisms 43 are respectively housed therein.

Specifically, the belt transmission mechanism 42 includes an output shaft 45 whose one end is connected to the crankshaft 31a of the engine 31 and rotatably supported by bearings 44, 44;
A first chain sprocket 4 fixed to the output shaft 45
6, an input shaft 48 disposed at a constant interval from the first chain sprocket 46 and rotatably supported by a bearing 47, 47, and a second chain sprocket 49 fixed to the human power shaft 48. , and a drive chain 50 wound between both chain sprockets 46 and 49.

Furthermore, the clutch mechanism 43 includes a flywheel 51 fixed to the large diameter portion 48a on one end side of the input shaft 48, one end of which is connected to a substantially central shaft of the flywheel 51, and the other end of which is connected to the main gear. It includes a clutch shaft 52 connected to the main shaft 33c of the row 33a, and a friction clutch 53 provided on the clutch shaft 52. The outer diameter of the flywheel 51 is set smaller than that of the conventional flywheel 51 in consideration of the moment of inertia generated in the belt transmission mechanism 42.

Therefore, according to this embodiment, since the transmission case 38, transfer case 39, etc. are attached in parallel to the side of the engine 31, the coupling rigidity of the power plant is increased, and the muffled noise at high engine speeds is sufficiently suppressed. can.

Furthermore, fluctuations in the rotational torque of the crankshaft 31a are first absorbed by the moment of inertia IPc generated by the heald transmission mechanism 42 such as the drive chain 50, and then by the moment of inertia rP generated by the flywheel 51. In other words, the minimum moment of inertia I required to absorb torque fluctuations
P, in addition to the flywheel 51, the belt transmission mechanism 42
IPr and IPc can share the IPI.
The flywheel 5 can be satisfied by the sum of
The outer diameter and wall thickness of 1 can be reduced to the necessary minimum.As a result, the weight of the vehicle can be reduced and the manufacturing cost can be reduced.

Furthermore, as described above, the moment of inertia of the belt transmission mechanism 42 is 1. . is also added in advance as part of the required moment of inertia IP1, thereby preventing the generation of a moment of inertia more than necessary, and therefore the main shaft 33c rotates synchronously with the crankshaft 31a. Therefore, it becomes possible to smoothly change gears.

FIG. 2 shows a second embodiment of the present invention, in which the diameter of the second chain sprocket 49 is set smaller than the diameter of the first chain sprocket 46 to increase speed. This makes it possible to increase the rotational speed of the flywheel 51 and increase the moment of inertia. Therefore, the moment of inertia is suppressed to the same level as the above-mentioned moment of inertia rpt, and the outer diameter of the flywheel 51 is further reduced. It can be made smaller, further promoting weight reduction of the vehicle body.

FIG. 3 shows a third embodiment of the present invention, in which a torsional damper 54 is provided inside the first chain sprocket 46. Therefore, torsional vibration to the output shaft 45 can be sufficiently suppressed.

It should be noted that the present invention is not limited to the configuration of the embodiment described above, but it is also possible to arbitrarily change the arrangement positions of the transmission case 38, transfer case 39, etc.

Effects of the Invention As is clear from the above explanation, according to the power transmission device of the present invention, a belt transmission mechanism is arranged between the crankshaft and the clutch mechanism to absorb rotational torque fluctuations of the crankshaft. Since the moment of inertia required for this purpose is shared by the belt transmission mechanism in addition to the flywheel serving as the clutch mechanism, the size of the flywheel can be made as small as possible. As a result, the weight of the vehicle body and the manufacturing cost can be reduced.

Further, by considering the inertia moment of the belt transmission mechanism in advance, generation of an inertia moment more than necessary is prevented, and therefore the crankshaft and the main shaft of the transmission can be rotated synchronously. Therefore, it becomes possible to smoothly change the gears of the transmission.

[Brief explanation of drawings]

FIG. 1 is a plan sectional view showing a first embodiment of a power transmission device according to the present invention, FIG. 2 is a plan sectional view showing a second embodiment of the invention, and FIG. 3 is a plan sectional view showing a third embodiment. 4A is a plan sectional view showing a conventional device, and FIG. 4B is a vertical sectional view of the conventional device. 31... Internal combustion engine, 31a... Crankshaft, 42...
Heald transmission mechanism, 43...Clutch mechanism, 51...Flywheel. Figure 4 (A) Figure 4 (B)

Claims (1)

[Claims] (1) A power transmission device that transmits the driving force of the crankshaft of an internal combustion engine to a transmission via a clutch mechanism including a flywheel and a belt transmission mechanism, the power transmission device comprising: between the crankshaft and the clutch mechanism; A power transmission device comprising the belt transmission mechanism.