JPH03129142A - Vibration restraining device for engine - Google Patents

Abstract

PURPOSE:To improve the operability and durability of a starter motor and restrain the vibration of an engine by separating a housing for receiving a balance shaft and the starter motor from an engine block to unify them. CONSTITUTION:A cylindrical housing 3 is fixedly connected to the side wall of the cylinder block 2 of a 4-cylinder engine 1 mounted on an automobile or the like. In the housing 3 are housed a balance shaft 4, a starter motor 5 and a rotation transmitting mechanism 6. Those components are unified together through the housing 3 formed separately from the cylinder block 2. Thus, the rotary shaft of the starter motor 5 does not directly receive exciting force of the balance shaft 4 so that the operability and durability of the starter motor can be improved to restrain the vibration of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vibration suppressing device for an engine that includes a balance shaft having a rigid mass that rotates in synchronization with a crankshaft.

(Prior art) In reciprocating engines that are widely used as automobile engines, vibrations are unavoidably generated due to the reciprocating motion of pistons and connecting rods, and this engine vibration is transmitted into the passenger compartment, causing unpleasant noise. This may occur.

As a countermeasure to this problem, there have conventionally been devices that include a balance shaft having a rigid mass that rotates in synchronization with the crankshaft to suppress vibrations of pistons and the like.

As this type of device, conventionally, for example, as shown in Fig. 4,
By attaching a balance weight 65 as a rigid mass to the rotating shaft 64 of the alternator 63, which rotates in synchronization with the crankshaft 62, and using the rotating shaft 64 of the alternator 3 as a balance shaft, the side of the ennon main body 61 can be There is a method that aims at compactness by effectively utilizing space (see Japanese Utility Model Application Publication No. 58-42546).

(Problem to be Solved by the Invention) However, in such a conventional device, since the rotating shaft 64 of the alternator 63 directly receives the excitation force caused by the rotation of the balance weight 65, the alternator 63 is affected particularly during high-speed operation. Problems arose in that operability deteriorated and durability decreased.

The present invention aims to solve these conventional problems.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a balance shaft that rotates in synchronization with the crankshaft and has an unbalanced mass with respect to its center of rotation, and a balance shaft that starts the crankshaft. A starter motor that generates rotational force and a rotation transmission mechanism that transmits the rotational force of the starter motor to the crankshaft via a balance shaft are provided, and the balance shaft, starter motor, and rotation transmission structure are housed in the same housing. This housing was fixed to the engine block in a predetermined positional relationship with respect to the crankshaft.

(Function) Based on the above configuration, during normal operation of the engine, the balance shaft rotates synchronously with the crankshaft at a predetermined speed, and the housing that houses the balance shaft is in a predetermined positional relationship with respect to the crankshaft. By being fixed to the engine block, the excitation force generated by the rotation of the unbalanced mass cancels out the vibration generated by the reciprocating movement of the piston and connecting rod, suppressing engine vibration and smoothing the rotation of the crankshaft. Make it.

The rotation transmission mechanism provided between the starter motor and the balance shaft does not transmit rotational force from the balance shaft to the rotating shaft of the starter motor, so that the excitation force generated due to the rotation of the balance shaft is directly transmitted. This prevents the signal from being transmitted to the rotating shaft of the starter motor.
It is possible to prevent the durability of the starter motor from deteriorating.

When starting the engine, as the rotary shaft of the starter motor rotates, the rotational force of the starter motor is transmitted to the balance shaft via the one-way rotation transmission PIi structure, and the crankshaft is started via the balance shaft.

During this startup, the rotation speed of the balance shaft is relatively low, so even if the starter motor is directly subjected to the excitation force generated by the rotation of the balance shaft on its rotating shaft, there is no need to worry about deterioration of its durability. rare.

By providing the housing that houses the balance shaft, starter motor, and rotation transmission mechanism separately from the engine block, it is easier to assemble the balance shaft in response to design changes such as the amount of engine wander and compression ratio. The productivity of Ennon equipped with a balance shaft can be improved.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

In Figures 1 and 2, 1 is 4 mounted on an automatic* etc.
It is a cylinder engine, and its Schilling block 2 I! !
! A cylindrical housing 3 is fixedly connected to the housing 3, and a balance shaft 4, a starter motor 5 to be described later, and a rotation transmitter are connected to the housing 3. ft6 etc. are housed therein, and these are made into a unit via a housing 3 which is formed separately from the shilling block 2. In the figure, 11 is a transmission, 12 is a sill head, and 13 is an oil pan.

A pulley 7 is connected to the tip of the balance shaft 4, and a timing belt 10 is hooked and rotated between the pulley 9 connected to the crankshaft 8, so that the balance shaft 4 and the crankshaft 8 synchronize in opposite directions. and rotate. In the case of a 4-cylinder Ennon 1, the balance shaft 4 is connected to the crankshaft 8.
Set the pulley ratio so that the number of rotations is doubled.

The housing 3 is formed by being divided into five housing members 14 to 18, and both ends of the balance shaft 4 are supported in parallel to the crankshaft 8 by the housing members 14 and 16, respectively, via bearings 21 and 22.

A twin balance mass 23 having a predetermined mass is integrally formed in the middle of the balance shaft 4 with a predetermined eccentricity. The unbalanced mass 23 is located on the side of the #2 cylinder and #3 cylinder of the engine 1, and is shaped so as to face the center of the crankshaft 8. As the unbalanced mass 23 rotates, The vibration of the engine 1 as a whole is reduced by offsetting the vibration force generated due to the reciprocating motion of the piston, connecting rod, etc.

A disk portion 24 is integrally formed in the medium heat portion of the unbalanced mass 23, and a bearing portion 25 for bearing the disk portion 24 is integrally formed in the housing member 15 to prevent center runout of the balance shaft 4.

On the other hand, an armature 32 that generates a rotational force inside the magnet 31 is rotatably supported by an armature shaft 36. An excitation current is passed through the coil 33 of the armature 32 via a brush 35 that is in sliding contact with the funmitator 34.

One end of the armature shaft 36 is supported by the housing member 18 via a bearing 37, and the other end is supported by an intermediate plate 38 via three bearings.

The armature shaft 36 and the balance shaft 4 are arranged coaxially with each other, and a planetary tooth 11 device 41 and a one-way clutch 45 are provided between them as the rotation transmission mechanism 6.

As shown in FIG. 3, the planetary gear device 41 has a center gear 42 integrally formed with one end of the armature shaft 36, an internal gear 43 fixed to the housing member 16, and three gears 42 and 43 between the two gears 42 and 43. planet gear 4
4 is interposed to transmit the rotation of the armature shaft 36 at a predetermined ratio at double speed.

The one-way clutch 45 includes an inner ring 47 connected to the rotating shaft 46 of each planet gear 44, an outer ring 48 connected to one end of the balance shaft 4, and both rings 4.
A ball 49 is interposed between the rings 47 and 48, and when the armature shaft 36 is rotationally driven, each of the four balls bites between the rings 47 and 48 to transmit rotational force.
When the balance shaft 4 is rotationally driven by the ennon 1, this biting does not occur, so the rotation of the armature shaft 36 is stopped.

Incidentally, instead of the one-way clutch 45 that transmits rotation in one direction as described above, a ratchet mechanism consisting of a gear connected to the balance shaft 4 side and a pawl connected to the armature shaft 36 side is provided. Also good.

I will explain the effect in detail.

During normal operation after starting the engine, rotational force is transmitted to the balance shaft 4 from the crankshaft 8 via the belt 10.
It rotates synchronously with the crankshaft 8 at twice the speed.

The housing 3 that houses the balance shaft 4 is fixed to the cylinder block 2 of the engine 1, so that the excitation force generated due to the rotation of the unbalanced mass 23 is converted into a secondary vibration force generated due to the reciprocating motion of the piston and connecting rod. It is possible to cancel vibrations, suppress vibrations of the ennon 1 as a whole, and make rotation of the crankshaft 8 smooth.

During this normal operation, due to the operation of the one-way clutch 45, rotational force is not transmitted from the balance shaft 4 to the 7-gear gear 36 of the starter motor 5, and the 7-way clutch 45 is operated.
The machine gear 7to 36 is stationary. Therefore, the excitation force generated due to the rotation of the balance shaft 4 is prevented from being directly transmitted to the armature shaft 36,
Deterioration of the operability and durability of the starter motor 5 can be prevented.

When starting the engine, as the armature shaft 36 of the starter motor 5 rotates, the rotational force of the armature shaft 36 is transmitted to the balance shaft 4 via the one-way clutch 45, and the crankshaft 8 is started via the balance shaft 4. During this startup, the rotational speed of the balance shaft 4 is also relatively low, so even if the excitation force of the balance shaft 4 is directly applied to the 7-gusset gear 36 of the starter motor 5, the operability and durability will deteriorate. There is almost no need to worry about it.

By providing the housing 3 that houses the balance shaft 4, starter motor 5, and rotation transmission mechanism 6 separately from the shilling block 2, it is possible to change the design of pistons and connecting rods due to changes in engine displacement, compression ratio, etc. It becomes easy to assemble the corresponding balance shaft 4, and the productivity of the engine equipped with the balance shaft 4 can be improved.

(Effects of the Invention) As described above, according to the present invention, the housing houses the balance shaft that rotates in synchronization with the crankshaft and the starter motor that transmits the starting force of the engine to the crankshaft via the balance shaft. Since these are separated from the engine block and made into a unit, the rotating shaft of the starter motor is not directly subjected to the excitation force of the balance shaft, which prevents deterioration of the starter motor's operability and durability. In addition to suppressing vibrations, the lateral space of the engine is effectively used to make the ennon more compact, and it is also easier to install a balance shaft to accommodate changes in engine displacement and compression ratio. productivity can be improved.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an engine showing an embodiment of the present invention;
The figure is a longitudinal cross-sectional view of the balance shaft and the starter motor, and FIG. 3 is a cross-sectional view as well. Fig. fIS4 is a front view of an engine showing a conventional example. 1...Engine, 2...Cylinder block, 3...
- Housing, 4... Balance shaft, 5... Starter motor, 6... Rotation transmission mechanism, 8... Crankshaft, 41... Planetary gear device, 45... One-way clutch.

Claims (1)

[Claims] A balance shaft that rotates in synchronization with the crankshaft and has an unbalanced mass with respect to its center of rotation, a starter motor that generates the rotational force that starts the crankshaft, and the rotational force of this starter motor that is used to drive the crank via the balance shaft. A rotation transmission mechanism for transmitting data to the shaft is provided, the balance shaft, starter motor, and rotation transmission mechanism are housed in the same housing, and this housing is fixed to the engine block in a predetermined positional relationship with respect to the crankshaft. Engine vibration suppression device.