JP4204571B2 - Engine balance device housing - Google Patents

Description

  The present invention relates to a housing for an engine balancing device, and more particularly to a housing for rotatably receiving a balancer shaft having a counterweight for canceling an excitation force generated by an engine piston.

  Two balancer shafts equipped with a counterweight for canceling the secondary vibration generated by the piston of the engine are placed under the crankshaft in the oil pan and cranked via a chain / sprocket mechanism or gear mechanism. A balancing device is known in which the rotation of the shaft is transmitted to the balancer shaft (see Patent Document 1).

According to the document 1, the housing that rotatably receives the balancer shaft is disposed below the cylinder block of the engine with the cylinder axis inclined with respect to the direction orthogonal to the axis of the crankshaft. An attachment portion for attaching the engine oil strainer is integrally formed at a portion of the wall between the two balancer shafts.
JP 2000-65148 A

  However, according to the conventional structure, the strainer mounting portion has to be extended downward from the bottom wall of the housing for the convenience of arranging the inlet of the strainer at the bottom of the oil pan, and the housing tends to be large. there were. In addition, what is disclosed in the above publication is a shape in which a part of the strainer mounting portion is bitten between two bearing holes in the bearing wall that supports the axial intermediate portion of the balancer shaft, and the bearing wall is divided. As a result, the rigidity of the bearing wall was reduced. In addition, because of these morphological circumstances, it is difficult to increase the support rigidity of the balancer shaft because the fastening bolt of the housing cannot be disposed between the two balancer shafts.

  Although it is conceivable to place the strainer mounting part in a position that does not penetrate into the bearing wall, this makes it necessary to provide a suction port at a position off the center of the engine crankshaft direction. However, there is a problem that the oil suction when the oil level is inclined during turning is deteriorated.

  The present invention has been devised to solve such problems of the prior art, and its main purpose is to increase the size of the housing, decrease the rigidity of the bearing wall, or to tilt the oil level. An object of the present invention is to provide an engine balancing device housing which is improved so as not to deteriorate the oil suction.

In order to achieve such an object, in order to rotatably receive two balancer shafts (13L and 13R) arranged in parallel with each other , a cylinder block in which a cylinder axis is inclined in a direction perpendicular to the axis of the crankshaft ( 2) In the housing (lower housing 14L) of the engine balancing device (4) disposed below 2), the invention according to claim 1 of the present application provides a tubular passage (26) communicating with the suction port of the oil pump. A fastening boss that is integrally formed along one side wall of the housing and that is inserted through a bolt for fastening the housing to the cylinder block is integrally formed at a side position of the tubular passage. It was supposed to be. According to the invention of claim 2, in addition to the above, a mounting portion (28) of the oil strainer (25) is integrally formed on the bottom wall of the housing, and the mounting portion of the oil strainer and the tubular passage are connected to one side. It was characterized by being integrally formed at a position below the balancer shaft (13L). Furthermore , in addition to the above, the invention of claim 3 comprises an upper housing (14U) and a lower housing (14L) that are vertically split, and a bearing hole that supports the two balancer shafts on the joint surface thereof. A bearing wall (23c) provided with (22c), and a bolt provided between the two balancer shafts and the outer side of one balancer shaft to fasten the upper housing and the lower housing to each other. The center of the mounting portion is arranged between the bolt provided on the side, and at least the outer peripheral portion of the mounting portion is connected to the bearing wall.

According to the first and second aspects of the present invention, since the tubular passage can be brought close to the fastening boss, the fastening rigidity of the balancing device with respect to the cylinder block can be increased without increasing the size of the housing of the balancing device for the engine. A great effect can be achieved in increasing the level.

In particular, with the configuration of claim 3 , it is not necessary to reduce the rigidity of the bearing wall, and the outer peripheral portion of the strainer mounting portion can be separated from the fastening bolt, so that the fastening operation can be facilitated. In addition, since the suction port can be arranged directly under the center of gravity of the engine, it is effective in making it less susceptible to the influence of liquid level fluctuations due to changes in the posture of the vehicle.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  1 and 2 show a mounting portion of a balance device in a reciprocating piston engine to which the present invention is applied. The engine E is an in-line four-cylinder engine in which the crankshaft 1 extends in the horizontal direction, and includes a cylinder block 2, a lower block 3, a balancing device 4, and an oil pan 5. The cylinder axis is inclined with respect to the orthogonal direction and mounted on the vehicle body.

  The balancing device 4 is for reducing the secondary vibration of the engine E caused by the reciprocating motion of the piston. The balancing device 4 is attached to the oil pan 5 by through bolts B1 inserted into the left and right side ends from below. The inner block is fastened to the lower surface of the lower block 3 (below the crankshaft 1). The balancing device 4 includes a large sprocket 7 fixed to the back side of the crank pulley 6 at the front end of the crankshaft 1 (hereinafter referred to as the crank pulley side), and the left side (hereinafter, the left and right direction toward the crank pulley). And a small sprocket 8 fixed to the front end of a balancer shaft (to be described in detail later) and a link chain 9 spanned between the large and small sprockets 6 and 7. The crankshaft 1 is driven to rotate by the rotational force of the crankshaft 1.

  The balancing device 4 includes a pair of left and right balancer shafts 13L and 13R having substantially the same shape, and the center of both balancer shafts 13L and 13R so as to support and accommodate these two balancer shafts 13L and 13R in parallel with each other. 14U, and an upper housing 14U and a lower housing 14L which are divided into two vertically along a plane passing therethrough.

  Both the balancer shafts 13L and 13R are linked to each other by a helical gear 15 (only one of which is shown) integrally coupled to the balancer shafts 13L and 13R. Here, as described above, the driving force of the crankshaft 1 is transmitted to the left balancer shaft 13L via the large sprocket 7, the small sprocket 8, and the link chain 9, and thus the rotational speed twice that of the crankshaft 1 is achieved. Thus, the left balancer shaft 13L is rotationally driven in the same direction as the crankshaft 1. The right balancer shaft 13R is rotationally driven in the opposite direction by the meshing of the helical gears 15.

  Further, since the balancing device 4 is fastened to the lower surface of the lower block 3 of the engine E with the cylinder axis inclined, the two balancer shafts 13L and 13R are positioned at the lower position of the left balancer shaft 13L. .

  On both balancer shafts 13L and 13R, first and second journal portions 16a and 16b having a relatively small diameter are disposed in front of the helical gear 15, and third and fourth journal portions 16c and 16d having relatively large diameters are disposed at the rear thereof. Each is integrally formed. In addition, a counterweight part 17 is integrally formed at the rear part of each balancer shaft 13L and 13R, the position of the center of gravity being biased radially outward from the center of rotation, and being divided into two front and rear parts with the third journal part 16c interposed therebetween. Has been.

  Flange portions 18 having an enlarged diameter are formed at opposing ends of the front / rear counterweight portion 17 across the third journal portion 16c. Thrust receiving surfaces 19 are formed on the opposing end surfaces of the flange portions 18.

  The shaft portion 20 of the counterweight portion 17 has a relatively small diameter in order to obtain the expected equivalent rotational mass while making the counterweight portion 17 as small as possible. Then, in order to compensate for the reduction in rigidity due to the reduced diameter, the attachment portion of the helical gear 15 and the third journal portion 16c and the third journal portion 13c and the fourth journal portion 14d are connected in the axial direction. The rib 21 is provided in the part over the full length of the both shaft parts 20 on the non-weight side. These ribs 21 are tapered so that the height dimension is reduced toward the center in the axial direction of each counterweight portion 17 in order to minimize the increase in weight due to the provision of the ribs 21 and to optimize the stress distribution. It is made into a shape.

  On the other hand, the journal portions 16a to 16d of both the balancer shafts 13L and 13R are supported by two divided first to fourth bearing holes 22a to 22d formed by joining the upper and lower housings 14U and 14L to each other. Is done.

  The journal portions 16a to 16d of the balancer shafts 13L and 13R are respectively placed on the half of the bearing holes 22a to 22d on the side of the lower housing 14L, and in this state, the upper housing 14U side of the bearing holes 22a to 22d is placed. The upper and lower housings 14U and 14L are joined to each other by aligning the halved portion of the upper and lower housings 14a to 16d with the journal portions 16a to 16d of the balancer shafts 13L and 13R. It will be rotatably accommodated in 14L. The thrust receiving surface 19 contacts the front and rear end surfaces of the bearing wall 23c in which the third bearing hole 22c is formed to receive the thrust force.

  As shown in FIG. 3, the upper and lower housings 14U and 14L are each provided with a plurality of bolts B2 inserted from above at appropriate positions, and third and fourth bearing holes 22c and 22d. It is fastened with three bolts B3 that pass through the walls 23c and 23d and are inserted from below. In particular, the parts of the bearing walls 23c and 23d on which radial acceleration due to the rotation of the counterweight portion 17 acts are loosened. It is considered that it becomes difficult to occur.

  A pump housing 24 provided with a trochoid lubricating oil pump (not shown) for pumping lubricating oil to various parts of the engine is bolted to the front end surface of the lower housing 14L. This lubricating oil pump (not shown) is provided at the shaft end of the right balancer shaft 13R, and when the right balancer shaft 13R rotates, an oil strainer 25 attached to the bottom wall of the lower housing 14L removes one of the lower housings 14L. The lubricating oil in the oil pan 5 is sucked through a tubular passage 26 provided in the side wall, and is pumped to various parts of the engine.

  The mounting portion 28 of the strainer cover 27 that holds the oil strainer 25 is integrally formed on the lower side of the two balancer shafts in the lower housing 14L, that is, on the lower position of the left balancer shaft 13L. The mounting portion 28 has a cylindrical boss shape, and the bolt provided between the two balancer shafts 13L and 13R of the bolt B3 for fastening the upper housing 14U and the lower housing 14L to each other and the lower side thereof. The center of the left balancer shaft 13L is arranged between the bolts provided on the outer side of the left balancer shaft 13L, and the bearing wall 23c provided with a half portion of the third bearing hole 22c in the middle portion in the front-rear direction of the lower housing 14L The outer periphery is connected. This enhances the rigidity of the bearing wall 23c that fastens the upper housing 14U and the lower housing 14L. Further, the tubular passage 26 integrally formed on one side wall of the lower housing 14 </ b> L is terminated at the joining surface of the pump housing 24.

  In this manner, the mounting portion 28 of the strainer cover 27 and the hollow tubular passage 26 are integrally formed at a position adjacent to the lower side of the left balancer shaft 13L on the bottom wall of the lower housing 14L, so that the lower housing 14L is particularly formed. Since the bearing walls 23a and 23b that support the front side of the third journal portion 16c of the balancer shaft 13L are connected by the strainer cover mounting portion 28 and the tubular passage 26, the rigidity of these bearing walls 23a and 23b is established. It greatly contributes to strengthening. In addition, since the space between the head of the bolt B3 that fastens the bearing wall 23c and the strainer mounting portion 28 can be sufficiently opened, the workability at the time of fastening the bolt does not have to be lowered.

  A fastening boss 30 for inserting a fastening bolt B1 with respect to the lower block 3 is provided at a position adjacent to the side of the end portion of the tubular passage 26, which contributes to increasing the fastening rigidity of the balancing device 4 with respect to the lower block 3. is doing.

  As described above, the oil strainer 25 is mounted directly below the left balancer shaft 13L on the lower side of the two balancer shafts on the bottom wall of the lower housing 14L, and is close to the vertical plane passing through the center of the crankshaft 1. The center of the engine E is located directly below the center of gravity of the engine E. In this way, the suction port 29 of the strainer cover 27 is positioned at a position where the fluctuation of the liquid level is least at the lowermost bottom portion of the oil pan 5 without greatly extending the strainer mounting portion 28 downward. Therefore, even if the liquid level of the lubricating oil fluctuates due to longitudinal acceleration or centrifugal force during traveling, the oil suction does not deteriorate. As a result, an increase in size of the lower housing 14L is avoided, which in turn contributes to a compact engine E.

Front sectional view showing a part of a main part of an engine to which the present invention is applied. A side sectional view showing a part of an essential part of an engine to which the present invention is applied. Bottom view of balancer lower housing

Explanation of symbols

1 Crankshaft 2 Cylinder block 4 Balance device 5 Oil pan 13L / 13R Balancer shaft 14U Upper housing 14L Lower housing 22c Bearing hole 23c Bearing wall 25 Oil strainer 26 Tubular passage 28 Mounting portion 29 Oil suction port 30 Fastening boss

Claims (3)

An engine balancer housing disposed below a cylinder block having a cylinder axis inclined with respect to a direction perpendicular to the axis of a crankshaft so as to rotatably receive two balancer shafts arranged in parallel with each other. ,
A tubular passage communicating with the suction port of the oil pump is integrally formed along one side wall of the housing, and
A housing for an engine balancing device, wherein a fastening boss for inserting a bolt for fastening the housing to the cylinder block is integrally formed at a side position of the tubular passage. An oil strainer mounting part is integrally formed on the bottom wall of the housing,
The housing of the balance device for an engine according to claim 1, wherein the mounting portion of the oil strainer and the tubular passage are integrally formed at a position below one balancer shaft. The housing is composed of an upper housing and a lower housing that are vertically split, and has a bearing wall provided with a bearing hole for supporting the two balancer shafts on a joint surface thereof.
It placed a center of the mounting portion between the upper housing and the the lower housing and to conclude mutually the two bolts provided on the outer side of the bolt and the balancer shaft provided between the balancer shaft together The housing for an engine balance device according to claim 2 , wherein at least an outer peripheral portion of the mounting portion is connected to the bearing wall.

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