JPH02245412A - Cylinder block of engine - Google Patents

Abstract

PURPOSE:To enable the flow of lubrication oil or the like and the rotation of a balancer shaft to be smoothly carried out respectively by arranging the return passage or the like of lubrication oil in the position where the interference with the balancer shaft on the side of cylinder can be avoided. CONSTITUTION:A pair of right and left balancer shafts 17 are arranged in a row in the positions adjacent to the inner walls (3) of a cylinder block at both sides of respective first to third cylinder bores 6a to 6c. And the balancer shaft 17 is formed by a counterweight part 18 arranged in an eccentric position to the axis and by an extended shaft part 19 extended from the one end thereof. On the other hand, on both sides of a fourth cylinder bore 6d where there is no balancer shaft 17, two of passages 10 communication with the inside of a crankcase are arranged. Further, respective passages 10 are opened in the symmetrical positions with reference to the row-directional center line of cylinder, and the passages on one side and those on the other side are utilized as oil return passages and ventilation passages in the inside of the crankcase respectively.

Description

Detailed Description of the Invention [Objective of the Invention] Industrial Application Fields The present invention provides a balancer shaft for canceling secondary excitation force in a 4-stroke, 4-cylinder engine, which is attached to the side of a cylinder row. The present invention relates to an engine cylinder block having a passage communicating between the cylinder head mounting surface side and the crankcase side for ventilating the crankcase or returning lubricating oil.

<Prior art> In order to cancel the secondary excitation force generated in the 4-cycle in-line 4-cylinder engine, which is said to be the most popular type of reciprocating piston engine for vehicles, a balancer shaft having a counterweight part is cranked. A structure in which the shaft rotates together with the shaft is known (Japanese Patent Laid-Open No. 61-10
(See Publication No. 4114, etc.).

On the other hand, in order to return the lubricating oil that lubricates the valve gear installed in the cylinder head to the oil pan, or to alleviate pressure pulsations in the crankcase caused by the reciprocating movement of the piston, the cylinder head is For installation, a passage is provided in the cylinder block that communicates between the end face and the inside of the crankcase. This passage is generally provided between adjacent cylinder bores or in a portion corresponding to the journal wall at both ends in the cylinder row direction,
In particular, the above-mentioned publication proposes a structure in which this passage is formed at a position passing through the space of the accommodation portion of the balancer shaft.

<Problems to be Solved by the Invention> However, as disclosed in the above publication, if the passage is opened toward the housing portion of the balancer shaft, the eccentrically provided counterweight portion rotates at high speed. As a result, the smooth flow of blow-by gas may be obstructed, or lubricating oil may adhere to the balancer shaft, causing rotational resistance.

The present invention has been made to solve the problems of the prior art, and its main purpose is to prevent the crankcase ventilation passage or lubricating oil return passage from interfering with the balancer shaft. The purpose of the present invention is to provide an improved engine cylinder block.

[Structure of the Invention] Means for Solving the Problems According to the present invention, the present invention provides a balancer shaft disposed on the side of a cylinder row consisting of a plurality of cylinders arranged in series. , an engine cylinder block having a passage communicating between a cylinder head mounting surface side and a crankcase side for ventilating the crankcase or returning lubricating oil, the passageway being on the side of the cylinder. The cylinder block of the engine is characterized in that it is disposed at a position avoiding the balancer shaft, or the passage is disposed at a position avoiding the balancer shaft in the axial direction of the balancer shaft. This is achieved by providing an engine cylinder block with special features. In particular, the space above the crankshaft that accommodates the balancer shaft and the passage may be separated only by a journal wall, or the bearing portion of the balancer shaft may be inserted into a balancer shaft receiving hole formed in the journal wall. It is a good idea to isolate yourself by doing something.

In this way, the passage for ventilating the crankcase or returning the lubricating oil and the balancer shaft do not interfere with each other, allowing the blow-by gas and return lubricating oil to flow smoothly and preventing the balancer shaft from rotating. Avoid encountering resistance.

Further, if this passage is provided in the axial direction of the balancer shaft, the widthwise dimension of the cylinder block does not need to be increased. In particular, if the space that accommodates the balancer shaft and this passage are separated by a journal wall, it is possible to more reliably prevent the rotation of the balancer shaft and the flow of blow-by gas or return lubricating oil from influencing each other. . Furthermore, if the space for accommodating the balancer shaft and the passage are isolated by fitting the bearing portion of the balancer shaft into the balancer shaft receiving hole formed in the journal wall, the above effect can be obtained and the balancer shaft The support rigidity of the shaft can be increased.

<Embodiments> Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a plan view of a cylinder block 1 in an in-line four-cylinder engine constructed according to the present invention.

This cylinder block 1 is made of cast aluminum alloy, for example, and has a water jacket 4 formed between a cylinder block outer wall 2 and a cylinder block inner wall 3.
A liner 5 cast into the cylinder block inner wall 3 located inside the water jacket 4 forms cylinder bores 6a to 6d in which pistons (not shown) slide.

The upper surface of the cylinder block 1 is ground smooth to form a cylinder head joint surface 7. Around the water jacket 4 on the cylinder head joint surface 7, at intermediate positions between the adjacent cylinder bores 6a to 6d and at both ends in the cylinder row direction, there are a total of 10 holes, in pairs at approximately equal intervals. A bolt hole 8 is bored along the cylinder axis. These bolt holes 8 are formed with internal threads for screwing head bolts for fastening a cylinder head (not shown).

Fourth cylinder bore 6d at cylinder head joint surface 7
Two pairs of passages 10 that communicate with the inside of the crankcase 9 (FIG. 3) are opened on both sides of the crankcase.

These passages 10 are opened at approximately symmetrical positions across the center line in the cylinder row direction, and one side functions as an oil return passage for returning lubricating oil that has lubricated around the valve mechanism to the oil pan. , the other side functions as a ventilation passage within the crankcase for circulating blow-by gas between the cylinder head and the crankcase. In the case of this embodiment, the engine is mounted at an angle so that the passage located on the right side in Fig. 1 mainly serves as an oil return passage (see Fig. 7).

Furthermore, on the right side of the cylinder block outer wall 2 between the second and third cylinder bores 6b and 6c, there is a lubricating oil discharge port for supplying lubricating oil to a valve mechanism provided in the cylinder head (not shown). A channel 11 is drilled parallel to the bolt hole 8.

As shown in FIG. 2, both ends of the cylinder block 1 in the cylinder row direction and the adjacent cylinder bores 6a to 6
At the intermediate position of d, there is a journal part of the crankshaft (
Journal walls 13a to 13e having bearing portions 12 are formed to pivotally support the bearings (not shown). These journal walls 13a to 13e are formed along a plane that is parallel to the cylinder axis and perpendicular to the cylinder row direction, and each pair of journal walls 13a to 13e are provided on the lower surface thereof to fasten a bearing cap (not shown). Ten bolt holes 14 are drilled along the cylinder axis. Further, an oil pan flange 15 is formed facing outward on the lower surface of the cylinder block 1, which is ground to a flat surface for joining an oil pan (not shown), and a plurality of bolt holes 16 are drilled therein. .

On the other hand, at positions relatively close to the cylinder block inner wall 3 on both sides of the first to third cylinder bores 6a to 6c, as shown in FIGS. A pair of left and right balancer shafts 17 are provided extending in the cylinder row direction at approximately symmetrical positions. As clearly shown in FIG. 4, these balancer shafts 17 are comprised of a counterweight section 18 provided at an eccentric position with respect to the axis, and an extended shaft section 19 extending from one end side of the counterweight section 18. It has become. A first bearing portion 20a is provided on the free end side of the extension shaft portion 19, and a second bearing portion 20b is provided on the other end portion of the counterweight portion 18.
A third bearing portion 20c is formed in the intermediate portion of each of the bearings 8 and 8, respectively. Further, the counterweight portion 18 is disposed on the sides of the second and third cylinder bores 6b and 6c in the central portion in the cylinder row direction, and the first bearing portion 20a is arranged on the first journal wall 13a on the first cylinder bore 6a side. The second bearing portion 20. is inserted into the first bearing hole 21a provided in the second bearing portion 20. b is the second bearing hole 21b provided in the fourth journal wall 13d between the third and fourth cylinder bores 6c, and the third bearing part 20c is the second bearing hole 21b.
Third journal wall 13 between third cylinder bores 6b and 6c
They are rotatably fitted into third bearing holes 21c provided in c.

In this way, the balancer shaft 17 is supported by the cylinder block 1 with sufficiently high rigidity so as not to swing around. At the same time, the fourth and fifth journal walls 13 through which blow-by gas and return lubricating oil flow
The space between d and 13c and the space between the first to fourth journal walls 13a to 13d in which the balancer shaft 17 is accommodated are formed in the fourth journal wall 13d itself and in the second bearing hole 21b of the journal wall. The second bearing portion 20b is fitted into the second bearing portion 20b, thereby separating the two bearing portions from each other.

The shaft ends of both balancer shafts 17 are connected to the first journal wall 1
Timing pulleys 22 are fixed to the ends of the shafts protruding from the shafts 3a, respectively.

As shown in FIG. 7, by connecting the timing pulley 22 and the crank pulley 32 fixed to the crankshaft 31 via the timing belt 33, both balancer shafts 17 can be doubled in length. are rotated in opposite directions at rotational speeds of . In the case of this embodiment, the balancer shaft 17 located on the left side in FIG. 7 rotates clockwise when viewed from the timing pulley 22 side, and the balancer shaft 17 located on the right side rotates counterclockwise. is being used. Further, a predetermined tension is applied to the timing belt 33 by a tension pulley 34 provided on the end face of the cylinder block.

Additionally, second and third bearing portions 20b and 20c are provided on the second journal wall 13b between the first and second cylinder bores 6a and 6b.
A large-diameter hole 23 through which the
A tool insertion hole 24 for machining the bearing hole 21b is open. This tool insertion hole 24 is closed by attaching a transmission case (not shown).

As shown in FIG. 5, the second and third cylinder bores 6b and 6
A skirt 25 extends from a portion adjacent to the bottom of the water jacket 4 at C toward both sides.

This skirt 25 extends in a direction generally perpendicular to the cylinder axis to partially surround the outer periphery of each balancer shaft 17, and then extends downward along a plane generally parallel to the cylinder axis, and then The oil pan flange 15 described above is formed therein.

As shown in FIG. 6, both sides of the cylinder between the first journal wall 13a and the second journal wall 13b, and the fifth journal wall 13e and the fourth journal wall 1
3d, a space 26 of an appropriate volume is defined on both sides of the cylinder by extending the skirt portions 25 on both sides toward the cylinder head joint surface 7 side. The passage 10 described above communicates with the inside of the crankcase 9 via this cavity 26.

Now, in an engine equipped with the balancer shaft 17 as described above, if the position of the passage 10 that communicates between the inside of the crankcase 9 and the cylinder head interferes with the balancer shaft 17, the passage will be cut off by the counterweight part 18. The area tends to be narrowed, which impedes the smooth flow of blow-by gas, and if the lubricating oil flowing down from the cylinder head side into the crankcase 9 comes into direct contact with the counterweight part 18 that rotates at high speed, the balancer shaft 17 It is possible that this may cause rotational resistance.

Therefore, in the present invention, two pairs of passages 10 are provided on both sides of the fourth cylinder bore 6d where the balancer shaft 17 is not present.
shall be installed. That is, balancer shaft 1
A passage is provided at a position that avoids interference with the balancer shaft 7 in its axial direction and also avoids the bearing of the balancer shaft 17. By doing so, the fluid can flow in a portion that is not affected by the balancer shaft 17.

Therefore, smooth circulation of return lubricating oil or blow-by gas can be obtained, and sufficient passage capacity can be secured. Furthermore, an increase in the width dimension of the cylinder block 1 can be suppressed as much as possible.

8 to 12 show modified embodiments of the present invention, parts corresponding to the first embodiment are given the same reference numerals and detailed explanation thereof will be omitted.

In the embodiment shown in FIG. 8, the fourth journal wall 13d
The second bearing hole 21b is a blind hole without passing through it in the axial direction. As a result, the space through which the blow-by gas and return lubricating oil circulate and the space in which the balancer shaft 17 is accommodated are further isolated, and the supporting rigidity of the shaft end of the balancer shaft 17 is not reduced. .

In each of the embodiments shown in FIGS. 9 to 12, the bearing on the fourth journal wall 13d side is omitted, and the space where blow-by gas and return lubricating oil flow and the balancer shaft 1
It is completely separated from the space in which 7 is accommodated by the fourth journal wall 13d.

In the embodiment shown in FIG. 9, a second bearing part 20b' is provided between the counterweight part 18 and the extension shaft part 19 of the balancer shaft 17, and the second journal wall 1
A second bearing hole 21b' is formed in 3b. At the same time, separate passages 10' are formed in the second and third journal walls 13b, 13c at positions avoiding both the bearing holes 21b', 21C.

10 to 12 show a structure in which the bearings of the balancer shaft 17 are provided at one end of one extension shaft part and at the middle part of the counterweight part 18, respectively. In other words, the balancer shaft 17 is supported at two points. It shows. and the first
Fig. 0 shows that separate passages 10' are provided in the fourth and fifth journal walls 13d and 13e, and Fig. 12 shows that
Another passage 10' is provided only in the fourth journal wall 13d. In this way, the passage can be formed not only in the space between the fourth and fifth journal walls 13d and 13e, but also in an appropriate position that avoids the bearing hole of each journal wall.

Furthermore, as shown in FIG. 12, if the skirt portion between the fourth and fifth journal walls 13d and 13c is made to bulge outward, the volume of the chamber through which the blow-by gas flows is expanded and oil is separated. In addition to improving the effectiveness, it is also possible to increase the rigidity of the transmission coupling flange F.

In any embodiment, the balancer shaft 17 is located at one end of the cylinder block 1 in the cylinder row direction (
The diameter of the bearing hole is larger on the front side so that it can be inserted from one direction along the axial direction. Each bearing part 20a-20c is made to be able to pass through in order.

[Effects of the Invention] As described above, according to the present invention, by providing the lubricating oil return passage or the crankcase ventilation passage in a position that avoids interference with the balancer shaft, smooth flow of the lubricating oil or blow-by gas can be achieved. This is highly effective in ensuring the stability and eliminating factors that cause rotational resistance of the balancer shaft.

[Brief explanation of drawings]

FIG. 1 is a plan view of a cylinder block constructed according to the present invention, and FIG. 2 is a bottom view. FIG. 3 is a cut end view taken along the line ■-■ in FIG. 1. 4 is a cut end view taken along the line TV-IV in FIG. 3. FIG. FIG. 5 is a cut end view taken along the line ■--■ in FIG. 1, and FIG. 6 is a cut end view taken along the same line °<VI-VI. FIG. 7 is an end view of the cylinder block on the pulley side. 8 to 12 are partial horizontal cross-sectional views showing modified embodiments, respectively. 1... Cylinder block 2... Cylinder block outer wall 3... Cylinder block inner wall 4... Water jacket 5... Liner 6a to 6d... Cylinder bore 7... Cylinder head joint surface 8... Bolt hole 9...Crankcase 10
...Passage 11...Lubricating oil discharge path 12...
・Bearing parts 13a to 13e... Journal wall 14... Bolt hole 15... Oil pan flange 16... Bolt hole 17... Balancer shaft 18... Counterweight part 19... Extension shaft Parts 20a to 20c... Bearing parts 21a to 21c... Bearing hole 22... Timing pulley 23... Opening 24... Tool insertion hole 25.
...Skirt portion 26...Vacancy 31...Crankshaft 32...Crank pulley 33...Timing belt 34...Tension pulley Patent Applicant: Honda Motor Co., Ltd.
Patent Attorney Yo Oshima - Figure 2 Figure 3 Figure 5 Figure 6r! ! J Figure 8 Figure 10 Figure 10'

Claims (4)

[Claims] (1) A balancer shaft installed on the side of a cylinder row consisting of a plurality of cylinders arranged in series, and a cylinder head mounting surface side and a crankcase side for ventilating the crankcase or returning lubricating oil. A cylinder block for an engine, the cylinder block having a passageway communicating between the cylinder block and the cylinder block, wherein the passageway is disposed at a side of the cylinder and away from the balancer shaft. . (2) A balancer shaft installed on the side of a cylinder row consisting of a plurality of cylinders arranged in series, and a cylinder head mounting surface side and crankcase side for ventilating the crankcase or returning lubricating oil. What is claimed is: 1. A cylinder block for an engine, wherein the passage is arranged in a position avoiding the balancer shaft in the axial direction of the balancer shaft. (3) The engine cylinder block according to claim 2, wherein a space above the crankshaft that accommodates the balancer shaft and the passage are separated by a journal wall. (4) The space above the crankshaft that accommodates the balancer shaft and the passage are isolated by fitting the bearing portion of the balancer shaft into the balancer shaft receiving hole formed in the journal wall. A cylinder block for an engine according to claim 2.