JP2003113898A - Housing for engine balancing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a housing for an engine balancing device improved so as not to cause an increase in size of the housing, lowering of rigidity of bearing walls, and deterioration of sucking of oil when oil level is tilted. SOLUTION: In this housing (lower housing 14L) for the engine balancing device 4 disposed on the lower side of the cylinder block 2 of an engine E having a cylinder axis tilted relative to a direction orthogonal to the axis of a crankshaft 1 to rotatably receive two balancer shafts 13L and 13R disposed parallel with each other, the mounting part 28 of an oil strainer 25 is integrally formed at the lower position of the balancer shaft 13L installed on the lower side of two balancer shafts. Thus since an oil suction port 29 is opened in the lowermost part of an oil pan 5 without largely extending the mounting part downward, the size and weight of the housing is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a housing of a balancing device for an engine, and more particularly to a housing for rotatably receiving a balancer shaft having a counterweight for canceling a vibration force generated by an engine piston. It is a thing.

[0002]

2. Description of the Related Art Two balancer shafts having counterweights for canceling a secondary vibration force generated by an engine piston are arranged below a crankshaft in an oil pan to provide a chain / sprocket mechanism and a gear mechanism. A balancing device that transmits the rotation of the crankshaft to the balancer shaft via the like is known from, for example, Japanese Patent Laid-Open No. 2000-65148.

In the one disclosed in the above publication, a housing that rotatably receives a balancer shaft is arranged below a cylinder block of an engine whose cylinder axis is inclined with respect to a direction orthogonal to the axis of the crankshaft. A mounting portion for mounting the engine oil strainer is integrally formed on a portion of the bottom wall of the housing between the two balancer shafts.

[0004]

However, according to the above-mentioned conventional structure, the strainer mounting portion has to be largely extended downward from the bottom wall of the housing in order to arrange the suction port of the strainer at the lowermost bottom portion of the oil pan. However, the housing tends to be large. In addition, the configuration disclosed in the above publication is such that a part of the strainer mounting portion is cut into between the two bearing holes in the bearing wall supporting the axially intermediate portion of the balancer shaft, and the bearing wall is divided. Therefore, the rigidity of the bearing wall was reduced. Moreover, due to these morphological circumstances, the fastening bolts of the housing cannot be arranged between the two balancer shafts, so that it is also difficult to increase the support rigidity of the balancer shaft.

It is conceivable to dispose the strainer mounting portion at a position where it does not bite into the bearing wall, but if this is done, the intake port must be provided at a position off the center of the crankshaft direction of the engine, so it must be placed horizontally. In the case of an engine, there arises a problem that oil suction is deteriorated when the oil surface is inclined during turning.

The present invention has been devised in order to solve the above-mentioned problems of the prior art, and its main purpose is to increase the size of the housing, reduce the rigidity of the bearing wall, and tilt the oil level. An object of the present invention is to provide a housing for an engine balancing device which is improved so as not to cause deterioration of oil suction when the engine is hit.

[0007]

In order to achieve such an object, the invention of claim 1 of the present application is to rotatably receive two balancer shafts (13L and 13R) arranged in parallel with each other. A housing (lower housing 14L) of the engine balancing device (4) arranged below the cylinder block (2) of the engine (E) in which the cylinder axis is inclined with respect to the direction orthogonal to the axis of the crankshaft (1). At the lower part of the balancer shaft (13L) provided on the lower side of the two balancer shafts, the mounting portion (28) of the oil strainer (25) is provided.
Is integrally formed.

With this configuration, the oil suction port (29) can be opened at the bottom bottom of the oil pan (5) without extending the strainer mounting portion largely downward, so that the housing can be made compact and lightweight. Can be promoted.

According to the second aspect of the invention, the housing is composed of an upper housing (14U) and a lower housing (14L) which are vertically split, and a bearing hole (22) for supporting the two balancer shafts on its joint surface.
c) having a bearing wall (23c) provided,
The center of the strainer mounting portion is arranged between the bolt provided between the two balancer shafts and the bolt provided on the outer side of the balancer shaft on the lower side in order to mutually fasten the upper housing and the lower housing, Moreover, at least the outer peripheral portion of the mounting portion is connected to the bearing wall.

With this configuration, the rigidity of the bearing wall for fastening the upper housing and the lower housing can be suppressed, and the strainer mounting portion is separated from the fastening bolts, so that the fastening work can be facilitated. Moreover, since the intake port can be arranged directly below the center of gravity of the engine, it is possible to make it less susceptible to the fluctuation of the oil level due to the change in the posture of the vehicle.

Further, in addition to the above, in the invention of claim 3, a tubular passage (26) for communicating the strainer mounting portion with the suction port of the oil pump is formed along one side wall of the lower housing, and A fastening boss (30) for inserting a bolt (B1) for fastening the housing to the cylinder block is formed integrally at a lateral position.

With this structure, the tubular passage increases the rigidity of the fastening boss without increasing the size of the housing.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings.

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

The balancing device 4 is for reducing the secondary vibration of the engine E caused by the reciprocating movement of the piston, and the oil is provided by the through bolts B1 which are inserted into the left and right ends of the engine from below. The lower surface of the lower block 3 (below the crankshaft 1) while being enclosed in the pan 5.
To be concluded. The balancing device 4 includes a front end portion of the crankshaft 1 (hereinafter, the crank pulley side is referred to as a front side).
Large sprocket 7 fixed to the back side of the crank pulley 6 and a small sprocket fixed to the front end of the balancer shaft on the left side (hereinafter, left and right direction is toward the crank pulley) (described in detail later). 8 and a link chain 9 hung between both large and small sprockets 6 and 7.
The rotational force of the crankshaft 1 transmitted via the and is driven to rotate.

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

The balancer shafts 13L and 13R are interlockingly connected to each other by a helical gear 15 (only one of which is shown) integrally connected to the balancer shafts 13L and 13R. Here, the left balancer shaft 13L is connected to the crankshaft 1 via the large sprocket 7, the small sprocket 8, and the link chain 9 as described above.
The driving force of the crankshaft 1 is transmitted.
The left balancer shaft 13L is rotationally driven in the same direction as the crankshaft 1 at a rotation speed twice as fast as the above. The right balancer shaft 1 is formed by meshing the helical gears 15 with each other.
3R is rotationally driven in the opposite direction.

An engine E having a cylinder axis inclined
Since the balancing device 4 is fastened to the lower surface of the lower block 3 of FIG. 1, the left balancer shaft 13L of the two balancer shafts 13L and 13R is at a lower position.

On both balancer shafts 13L and 13R,
The first and second journal portions 16a and 16b having a relatively small diameter are integrally formed in front of the helical gear 15, and the third and fourth journal portions 16c and 16d having a relatively large diameter are integrally formed behind the helical gear 15. In addition, each balancer shaft 13L ・ 1
A counterweight part 17 is formed integrally with the rear part of the 3R so as to deviate the position of the center of gravity from the center of rotation to the outside in the radial direction and is divided into two parts in the front and rear with the third journal part 16c interposed therebetween.

An enlarged flange portion 18 is formed at each of opposite ends of the front-rear counterweight portion 17 which sandwich the third journal portion 16c. These flange parts 1
Thrust receiving surfaces 19 are formed on the mutually opposing end surfaces of 8.

In order to make the counterweight portion 17 as small as possible and to obtain a desired equivalent rotating mass, the shaft portion 20 of the counterweight portion 17 has a relatively small diameter.
And in order to compensate for the decrease in rigidity due to the smaller diameter,
A rib 21 that connects the mounting portion of the helical gear 15 and the third journal portion 16c and the third journal portion 13c and the fourth journal portion 14d in the axial direction.
Are provided in the portion of the shaft 20 over the entire length on the anti-weight side. These ribs 21 are tapered so that the height dimension becomes smaller toward the center of each counterweight portion 17 in the axial direction in order to minimize the weight increase due to the provision of the ribs 21 and optimize the stress distribution. It is shaped.

On the other hand, both balancer shafts 13L and 13R
Each of the journal portions 16a to 16d is formed by joining the upper and lower housings 14U and 14L to each other, and is divided into first to fourth bearing holes 22a to 22d.
Supported by.

Both balancer shafts 13L are provided at the halves of the respective bearing holes 22a to 22d on the lower housing 14L side.
・ Each journal portion 16a to 16d of 13R is placed, and in this state, the half portion of each bearing hole 22a to 22d on the upper housing 14U side is aligned with each journal portion 16a to 16d of both balancer shafts 13L and 13R. Upper and lower housings 14U ・ 14
By joining L to each other, both balancer shafts 13L and 13R are rotatably accommodated in both housings 14U and 14L. The thrust receiving surface 19 described above has a bearing wall 23c in which the third bearing hole 22c is formed.
It comes in contact with both front and rear end surfaces to receive the thrust force.

As shown in FIG. 3 as well, the upper and lower housings 14U and 14L have a plurality of bolts B2 inserted from above at appropriate positions, and third and fourth bearing holes 22c.
Bearings that are fastened with three bolts B3 that penetrate through the bearing walls 23c and 23d provided with 22d and are inserted from below, and in which radial acceleration due to rotation of the counterweight portion 17 acts in particular. It is designed so that the walls 23c and 23d are unlikely to come loose.

A pump housing 24 in which a trochoidal type lubricating oil pump (not shown) for pumping lubricating oil to various parts of the engine is provided on the front end surface of the lower housing 14L.
Is bolted. The 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, one of the oil strainer 25 attached to the bottom wall of the lower housing 14L and the lower housing 14L is removed. 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, below the left balancer shaft 13L. The mounting portion 28 has a cylindrical boss shape, and is located on the lower side of the bolts B3 for fastening the upper housing 14U and the lower housing 14L to each other among the two balancer shafts 13L and 13R. The center is arranged between the left balancer shaft 13L and a bolt provided on the outer side, and the lower housing 14L
The outer peripheral portion of the third bearing hole 22c is connected to a bearing wall 23c provided with a half-divided portion of the third bearing hole 22c. As a result, the rigidity of the bearing wall 23c that fastens the upper housing 14U and the lower housing 14L is enhanced. Further, the tubular passage 26 integrally formed on one side wall of the lower housing 14 </ b> L has its end reaching the joint surface of the pump housing 24.

In this way, the mounting portion 28 of the strainer cover 27 and the hollow tubular passage 26 are integrally formed in the bottom wall of the lower housing 14L at a position adjacent to and below the left balancer shaft 13L. 14L, particularly the bearing walls 23a.2 supporting the front side of the balancer shaft 13L from the third journal portion 16c.
3b between the strainer cover mounting portion 28 and the tubular passage 2
6 will be connected, so these bearing walls 23a
-It greatly contributes to increase the rigidity of 23b. Moreover, since the space between the head of the bolt B3 for fastening the bearing wall 23c and the strainer mounting portion 28 can be sufficiently opened, workability at the time of fastening the bolt can be prevented from being lowered.

A fastening boss 30 through which a fastening bolt B1 for the lower block 3 is inserted is provided at a position adjacent to the side of the terminal end of the tubular passage 26 to enhance the fastening rigidity of the balancing device 4 with respect to the lower block 3. Contribute to.

As described above, the oil strainer 25 is directly attached to the bottom wall of the lower housing 14L below the lower left balancer shaft 13L of the two balancer shafts, and passes vertically through the center of the crankshaft 1. The center of the engine E is arranged at a position close to the surface, that is, substantially directly below the center of gravity of the engine E. In this way, the strainer mounting portion 28 does not greatly extend downward,
The suction port 29 of the strainer cover 27 is located at the position where the liquid level fluctuation is smallest in the lowermost bottom portion of the oil pan 5. Therefore, even if the liquid level of the lubricating oil fluctuates due to longitudinal acceleration or centrifugal force during traveling, oil suction does not deteriorate. Further, this avoids an unnecessarily large size of the lower housing 14L, which in turn contributes to downsizing of the engine E.

[0030]

As described in detail above, according to the present invention, in the balancing device arranged below the lower block,
By offsetting the mounting portion of the oil strainer downward from the center of the lower housing (the structure of claim 1), the oil suction port is opened at the bottom of the oil pan without greatly extending the strainer mounting portion downward. Therefore, it is not necessary to increase the size of the lower housing, which contributes to the weight reduction of the engine.

Further, by providing the strainer mounting portion at a position where it does not overlap the bearing wall as much as possible (construction of claim 2), the rigidity of the bearing wall is not reduced and the outer peripheral portion of the strainer mounting portion is separated from the fastening bolt. Since they can be separated, the fastening work can be facilitated. Moreover, since the intake port can be arranged directly below the center of gravity of the engine, it is effective in making it difficult to be influenced by the liquid level fluctuation due to the change in the posture of the vehicle.

Further, by providing the tubular passage in the housing and providing the fastening boss on the side of the tubular passage (the constitution of claim 3), the tubular passage can be brought close to the fastening boss, and therefore the balancing device for the lower block. It is effective in increasing the rigidity of the fastening portion.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view showing a part of an essential part of an engine to which the present invention has been applied.

FIG. 2 is a side sectional view showing a part of an essential part of an engine to which the present invention is applied.

FIG. 3 is a bottom view of the lower housing of the balancer.

[Explanation of symbols]

1 crankshaft 2 cylinder block 4 balancing devices 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 part 29 Oil inlet 30 fastening boss

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yotsugu Kudo             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory F term (reference) 3G013 AA00 BB04 BB19 BD41 CA11                 3G015 AA00 BH00 CA11 DA02 DA06                       DA11 EA05

Claims (3)

[Claims] 1. A balancing device for an engine arranged below a cylinder block in which a cylinder axis is inclined in a direction orthogonal to an axis of a crankshaft so as to rotatably receive two balancer shafts arranged in parallel with each other. The housing of the engine balancing device, wherein the mounting portion of the oil strainer is integrally formed at a position below the lower balancer shaft of the two balancer shafts in the housing. 2. The housing is composed of an upper housing and a lower housing which are split into upper and lower parts, and a bearing wall provided with a bearing hole for supporting the two balancer shafts in a joint surface thereof, wherein the upper housing and the lower housing are provided. Centering the mounting portion between a bolt provided between the two balancer shafts and a bolt provided outside the lower balancer shaft for fastening the lower housing to each other, and The housing of the engine balancing device according to claim 1, wherein at least an outer peripheral portion of the mounting portion is connected to the bearing wall. 3. A tubular passage is formed along one side wall of the lower housing, the tubular passage communicating the inner circumference of the mounting portion with the suction port of the oil pump, and at a lateral position of the tubular passage with respect to the cylinder block. The housing of the engine balancing device according to claim 1 or 2, wherein a fastening boss through which a bolt for fastening the housing is inserted is integrally formed.