JP2000170842A - Engine with balance shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the engine with a balance shaft which can increase the installation rigidity of an auxiliary machine without the increase of the number of part items and assembly hour and reduce an indoor noise. SOLUTION: In an engine provided with balance shafts 16a, 16b on the side of a crankshaft 7, for example, the installation parts 29, 30 of an auxiliary machine such as an alternating current generator are formed integrally to a bearing wall 25 and the side wall of an oil pan 3 in which the bearings 27a, 27b of the balance shaft in the cylinder block consisting of an upper block 1 and lower block 2 are provided. Thereby, as originally the installation part is provided on the part with high rigidity, the installation rigidity of the auxiliary machine can be increased without increasing the number of part items and assembly man-hour.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine with a balance shaft provided with a balance shaft for canceling vibration on a side of a crankshaft.

[0002]

2. Description of the Related Art Conventionally, auxiliary equipment such as an alternator and an air conditioning compressor is generally mounted on a cylinder block. As a result, there is a problem that room noise increases. On the other hand, an improved accessory mounting bracket has been proposed in Japanese Utility Model Laid-Open No. 5-15545.

[0003]

However, according to the prior art, the number of parts and the number of assembling steps are increased due to the necessity of a high-rigidity accessory mounting bracket, so that the production cost must be increased. .

[0004] The present invention has been devised to solve such problems of the prior art, and its main objects are as follows.
It is an object of the present invention to provide an engine with a balance shaft configured to increase the mounting rigidity of an auxiliary device without increasing the number of parts and the number of assembling steps, thereby reducing indoor noise.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, in the engine E having the balance shafts 16a and 16b on the side of the crankshaft 7,
For example, an alternator disposed below the balance shaft on the bearing wall 25 of the cylinder block (upper block 1 and lower block 2) provided with the balance shaft bearings 27a and 27b and the side wall of the oil pan 3 9, the attachment parts 29 and 30 of the auxiliary machine are integrally formed. With this configuration, since the mounting portion can be provided in a portion having originally high rigidity, the mounting rigidity of the auxiliary machine can be increased without increasing the number of parts and the number of assembling steps. Also, by providing the accessory mounting portion, the rigidity of the balance shaft support portion can be increased. In addition, since the auxiliary equipment can be arranged by effectively utilizing the space (the depression 33) below the balance shaft, it is possible to suppress an increase in the size of the engine.

According to the second aspect of the present invention, in an engine with a balance shaft, an accessory mounting portion is integrally formed on a bearing wall of a cylinder block provided with a bearing for the balance shaft, and the balance is provided outside the crank chamber 32. The shaft housing chamber 31 is integrally formed, and is mounted on the vehicle body with the crankshaft oriented parallel to the axle and the side where the balance shaft housing chamber is provided facing the vehicle interior. According to this, since the side wall of the crankcase having a double structure formed by the balance shaft housing is opposed to the cabin, noise radiated to the cabin can be reduced. In addition, since the accessory mounting portion is formed on the highly rigid bearing wall, the mounting rigidity of the accessory is increased, and the rigidity of the balance shaft support portion is increased by integrally forming the accessory mounting portion.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment shown in the accompanying drawings.

FIG. 1 shows a four-cycle V to which the present invention is applied.
FIG. 3 is an elevation view of a type 8-cylinder engine on a crank pulley side.

The engine E has an upper block 1 having a pair of cylinder banks having a narrow angle of 90 degrees, a lower block 2 joined to a lower surface of the upper block 1, and a lower block 2 joined to a lower surface of the lower block 2. It comprises an oil pan 3 and a cylinder head 4 joined to each upper surface of both cylinder banks of the upper block 1. Above each cylinder head 4, two camshafts 5 are provided. These camshafts 5 are covered with a head cover 6 joined to the upper surface of the cylinder head 4.

A crankshaft 7 is supported by a main bearing on the joint surface between the upper block 1 and the lower block 2, as in a known engine.

An air conditioner compressor 8 is mounted on the right side of the crankshaft 7 in the upper block 1, and an AC generator 9 is mounted on the left side of the crankshaft 7 in the lower block 2. The compressor 8 and the alternator 9 are linked to the crankshaft 7 via a belt / pulley mechanism (not shown).

A crank sprocket 10 is fitted on the crankshaft 7 at an axially inner position of the crank pulley, and a drive gear 11 is further axially inward of the crank pulley.
Is fitted.

The driven gear 11 simultaneously meshes with two driven gears 12 provided at symmetrical positions with respect to a plane passing through the center of the crankshaft. And in these two driven gears 12,
The small sprockets 13 are provided integrally with each other.
A camshaft driving silent chain 15 is wound around a cam sprocket 14 provided on the camshaft 5. Thus, the rotational force of the crankshaft 7 is transmitted to each of the two camshafts 5 of both banks.

The upper block 1 and the lower block 2
The two balance shafts 16a and 16b are divided from a horizontal plane through which the center of the crankshaft passes, and their axes extend parallel to the crankshaft 7 at vertically symmetrical positions around the divided surface.
Is pivoted.

Of these two balance shafts, a balance shaft sprocket 17 is fitted to a shaft end of a shaft 16b supported on the lower block 2 side. By winding a silent chain 19 between the balance shaft sprocket 17, the crank sprocket 10, and a pump sprocket 18 fixed to an oil pump (not shown) attached to the lower surface of the lower block 2, a lower side is provided. The balance shaft 16 b and the oil pump rotate in conjunction with the crankshaft 7.

The two balance shafts 16a and 16b are
The synchronizing gears 20a and 20b having the same number of teeth fitted on the inner side in the axial direction of the balance shaft sprocket 17 rotate in opposite directions at the same rotational speed.

The balance shafts 16a and 16b are arranged on the tight side of the silent chain 19 with respect to the rotation direction of the crankshaft 7. Thereby, the relative phase angle error between the crankshaft 7 and the balance shafts 16a and 16b can be minimized.

The silent chain 15 wound around the cam sprocket 14 of each cam shaft 5 and the silent chain 1 wound around the balance shaft sprocket 17 and the pump sprocket 18 in both cylinder banks.
Each of 9 is provided with a chain tensioner 22 whose pressing force is automatically adjusted by a hydraulic plunger 21 and a chain guide 23 for steadying. The chain tensioner 22 and the chain guide 23 are fixed to appropriate positions on the end faces of the upper block 1, the lower block 2, the oil pan 3, and the cylinder head 4 on the side of the crank pulley using bolts or the like.

As shown in FIG. 2, each of the upper block 1 and the lower block 2 constituting the cylinder block
It has a bearing wall 25 which forms a continuous wall surface when the two are combined, and on which a main bearing 24 for supporting the crankshaft 7 is formed. A bearing cap 26 made of an iron-based material is cast into a bearing wall of the lower block 2 that is cast with an aluminum-based material. Then, by the bolt B1 inserted into the bearing cap 26,
The upper block 1 and the lower block 2 are fastened on both left and right sides of the main bearing 24.

On the bearing wall 25, the balance shafts 16a and 16
The bearings 27a and 27b for supporting b are provided. An upper stay 28a (see FIG. 3) of the AC generator 9 is fixed to the side of the bearing 27b in the bearing wall 25 of the lower block 2 provided with the bearing 27b of the lower balance shaft 16b. The mounting part 29 is formed integrally.

In order to make the height of the engine E as small as possible and to secure a required oil storage capacity, the oil pan 3 has a flat bottom and a shape with a large side projecting. A lower mounting portion 30 for fixing a lower stay 28b (see FIG. 3) of the AC generator 9 is formed integrally with a side wall end of the oil pan 3 that protrudes laterally. Further, as shown in FIG. 4, the balance shaft 16a is provided on one of the side walls of the upper block 1 and the lower block 2.
An accommodation chamber 31 for accommodating 16b is formed so as to bulge outward from the crank chamber 32. Due to this morphological characteristic, especially on one side of the lower block 2 and the oil pan 3,
A depression 33 is formed. The alternator 9 is arranged so that a part thereof is immersed in the depression 33. Thereby, the amount of protrusion of the AC generator 9 to the side is reduced.

The parts provided with the AC generator mounting parts 29 and 30 are particularly high in rigidity among the parts of the engine E, so that the number of parts and the number of assembling steps are not increased and the AC generator is not increased. 9 can be supported with high rigidity.

If the engine E is mounted on the vehicle body with the crankshaft 7 oriented parallel to the axle and the side where the balance shafts 16a and 16b are provided facing the cabin, the balance shaft accommodation chamber 31 Since the side wall of the cylinder block composed of the upper block 1 and the lower block 2 having the double structure faces the passenger compartment side, it is possible to expect a further reduction in radiation noise to the passenger compartment.

[0024]

As described above, according to the present invention, the mounting rigidity of the auxiliary equipment can be increased without increasing the number of parts and the number of assembling steps, and the vibration of the auxiliary equipment can be suppressed with this. A great effect can be obtained in reducing the radiation noise to the room. In particular, if the side on which the balance shaft is provided is directed toward the cabin when the engine is mounted on the vehicle body, the effect of reducing the radiation noise generated by the cylinder block can be further enhanced, and the cabin is quiet. A great effect can be obtained in addition to improving the performance.

[Brief description of the drawings]

FIG. 1 is an elevational view of a V-type engine to which the present invention is applied, on a crank pulley side.

FIG. 2 is a longitudinal sectional view of a main part of a crank pulley side bearing wall portion of the engine shown in FIG. 1;

FIG. 3 is an enlarged view of a main part of the present invention.

FIG. 4 is a longitudinal sectional view of a main part of a crankcase portion of the engine shown in FIG. 1;

[Explanation of symbols]

 E Engine 1 Upper block 2 Lower block 3 Oil pan 7 Crankshaft 9 AC generator (Auxiliary equipment) 16a / 16b Balance shaft 25 Bearing wall 29/30 Auxiliary equipment mounting part 31 Balance shaft storage chamber 32 Crank chamber 33 Depression

Claims (2)

[Claims] 1. An engine with a balance shaft having a balance shaft on a side of a crankshaft, wherein the balance shaft is provided on a bearing wall of a cylinder block provided with a bearing of the balance shaft and a side wall of an oil pan. An engine with a balance shaft, wherein an attachment portion of an auxiliary machine disposed below the vehicle is integrally formed. 2. An engine with a balance shaft having a balance shaft on a side of a crankshaft, wherein an accessory mounting portion is integrally formed on a bearing wall of a cylinder block provided with a bearing of the balance shaft, and the crank is provided. A balance shaft receiving chamber is integrally formed outside the chamber, and is mounted on the vehicle body with the crankshaft directed parallel to the axle and the side where the balance shaft receiving chamber is provided facing the passenger compartment. An engine with a balanced shaft.