JP3120317B2 - Cylinder block for multi-cylinder engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder block of a multi-cylinder engine, which increases the engine displacement without changing the height and size of the engine body or reduces the size of the engine without changing the engine displacement. Related to the technology to achieve.

[0002]

2. Description of the Related Art As a prior art of a cylinder block of a multi-cylinder engine of this kind, a prior art related to the proposal of the present applicant, for example, shown in FIG.
Publication). Here, FIG. 6 is a side view in which a main part of the vertical water-cooled diesel engine is cut away. FIG. 4 is a perspective view of the crankshaft of the engine.

In a multi-cylinder engine, as shown in FIG.
A plurality of cylinders 2, a crankcase 20, and a crankshaft 8
Are formed integrally with each other, a tunnel-type support hole 22 is formed in each of the bearing walls 21, and a split bearing box 11 is assembled in advance to each of the intermediate journals 8 a of the crankshaft 8. Connect the crankshaft 8 to the crankcase 2
0 is inserted in the rear in the support hole 22 of the tunnel drilled in the bearing wall 21 from (flywheel 7 side) embedded in the crankcase 20, fitted in the bearing housing 11 in the respective support holes 22 It is fixed, and the intermediate journal 8a of the crankshaft 8 is pivotally supported by a central bearing hole 12 of the bearing housing 11. 6 denotes the entire diesel engine, 1 denotes a cylinder block integrally formed with a crankcase, 3 denotes a cylinder head, 4 denotes a gear case, 5 denotes a fan drive pulley, 6 denotes a cooling fan, 9 Indicates an oil pan.

In the prior art, a two-part bearing box 11 is previously assembled to each intermediate journal 8a of the crankshaft 8, and the crankshaft 8 is bored in the bearing wall 21 from the rear of the crankcase 2 in a tunnel-type support hole. 22, the rotation radius R of the crank pin 8b and the swing radius of the crankshaft 8 (the maximum outer diameter R 'in FIG. 4) are the same as those of the tunnel type. It is limited by the inner diameter of the support hole 22.

On the other hand, it is required to increase the rotation radius R of the crank pin 8b to increase the displacement of the piston 15 by increasing the stroke. In such a case, in the above-described conventional engine, it is necessary to increase the inner diameter of the tunnel-type support hole 22 and, consequently, the outer diameter of the bearing housing 11, and the height of the cylinder block 1 increases accordingly. In other words, without changing the displacement of the engine,
It is impossible to reduce the height of the cylinder block 1 by reducing the inner diameter of the cylinder block and the outer diameter of the bearing housing 11.

In order to solve the above problem, the present applicant has developed a cylinder block shown in FIG. 5 (hereinafter referred to as a prior art example). Here, FIG. 5 is a vertical sectional front view of the cylinder block according to the prior invention example. This example of the prior art is based on one end 2A of the cylinder 2 which protrudes into the crank chamber side.
Left and right neighboring parts 2a
2a, a pair of left and right cut-out recesses 2c, 2c for avoiding interference with the connecting rod large end portion 17 is formed.
The cylinder length is further extended while avoiding interference between the A and the connecting rod large end portion 17, and the displacement is increased without changing the height of the cylinder block 1, thereby increasing the output of the engine.

The center bearing hole 12 of the bearing housing 11
In order to maintain its concentric bearing accuracy high,
Each split bearing box 11 is fitted and fixed in a tunnel-type support hole 22 formed in each bearing wall 21, and in this state, the cylinder block 1 is mounted on a drilling device, and a plurality of bearing boxes 11 are penetrated. Drill the bearing hole 12 at one time. In addition, the crankshaft 8 is assembled in advance by assembling a split bearing box 11 on the intermediate journal 8a of the crankshaft 8 in advance.
In this state, the crankshaft 8 is inserted into the crankcase 20 through the support hole 22 from one end of the crankcase 2 (on the side of the flywheel 7), and the bearing box 11 is inserted into each support hole 22. The concentric bearing accuracy when the bearing hole 12 is opened by fitting and fixing is reproduced.

[0008] As described above, the crankshaft 8 is in a state assembled with the bearing housing 11 to the respective intermediate journals 8a, incorporated in the crank case 20 are sequentially inserted into the support hole 22 drilled in a plurality of bearing wall 21 Therefore, the crankshaft 8
A fixed insertion gap is formed between the support hole 22 and the bearing box 11 so as not to prevent the bearing box 11 assembled into the support hole 22 from being inserted into the support hole 22, and one end (lower edge) 2 of the cylinder 2 is formed.
The amount of intrusion of A is restricted so as not to interfere with the support hole 22 formed in the bearing wall 21.

[0009]

In the above conventional example (FIG. 6) and the prior art example, when the rotation radius R of the crank pin 8b is increased to increase the piston stroke, the piston skirt 15b moves at the bottom dead center of the piston. Cylinder 2
Protrudes from the lower edge. Therefore, the slap sound of the piston 15 is easily generated. When the rotation radius R of the crankpin 8b is increased, the swing radius R 'of the crankshaft 8 is also increased, and the inner diameter of the support hole 22 and the outer diameter of the bearing box 11 must be increased. In other words, without changing the displacement of the engine, the inside diameter of the support hole 22 and the outside diameter of the bearing box 11 cannot be reduced, and the height of the cylinder block 1 cannot be reduced.

The present invention has been made in view of such circumstances, and it is intended to further increase the cylinder length to suppress the generation of the slap noise without changing the height of the cylinder block. The technical problem is to increase the engine displacement by increasing the stroke of the piston without changing it, in other words, to reduce the size of the engine without changing the engine displacement.

[0011]

In order to solve the above-mentioned problems, the present invention is configured as follows. As shown in FIGS. 1 to 3, a plurality of cylinders 2 are provided.
, A crankcase 20 and a plurality of bearing walls 21 for supporting the crankshaft 8 are integrally formed, and a tunnel-type support hole 22 is formed in each of the bearing walls 21, and a crankshaft is provided in each of the support holes 22. In a cylinder block of a multi-cylinder engine constituted by internally fitting and fixing a bearing box 11 for pivotally supporting each intermediate journal 8a, one end 2 of the cylinder 2 is provided.
To plunge the A to crank chamber side, inrush side of the cylinder 2
Near the left and right where the connecting rod large end 17 of one end 2A approaches
Interference between the parts 2a and 2a with the connecting rod large end 17
To form a pair of left and right cutout recesses 2c
The tunnel-type support hole 22 formed in the bearing wall 21 is
The rush side one end 2A of the cylinder 2 is overlapped,
The swing radius R 'of the crankshaft 8 is set to each of the bearing walls 2.
While being set larger than the inner diameter of the first support hole 22,
A pair of recessed recesses 23 are formed in each of the support holes 22.
Then, the crankshaft 8 is
Can pass through a pair of crank arm tips 8c, 8c
It is characterized in that it is configured to function .

[0012] The invention described in Claim 2, FIG. 1
(A) and FIG. 2 , in the cylinder block of the multi-cylinder engine according to claim 1, each of the bearing walls 2.
1 has a lower wall portion 23b which lacks the lower portion of the support hole 22.
And penetrate the lower half of the bearing housing 11 in the left-right direction.
The lower left and right halves of each bearing wall 21 are tightened with
By tying, the bearing housing 11 is placed in the support hole 22.
The inner fitting is fixed while tightening from the left and right
It is also characterized by the following.

[0013]

In the invention described in [Operation and Effect of the Invention (a) according to claim 1, of the inrush one end 2A of the cylinder 2 to the crank chamber side
Was, in the lateral vicinity of 2a · 2a which connecting rod big end 17 of the inrush-side end portion 2A of the cylinder 2 approaches, the co
A pair of left and right cutout recesses 2c, 2c is formed to avoid interference with the large rod end 17, and the tongue formed in the bearing wall 21 is formed.
Flannel-shaped support hole 22 and one end 2 of the cylinder 2 on the entry side.
A is overlapped with A, so that interference between the one end 2A of the cylinder 2 and the large connecting rod end 17 is avoided, and the cylinder length is set to the dimension D where the one end 2A of the cylinder 2 and the support hole 22 overlap. it is possible to extend the at bottom dead center of the piston, the contact area of the piston and the piston skirt increases, the bottom dead center of the piston
Slap sound can be suppressed.

(B) According to the first aspect of the present invention,
Stroke up without changing engine height
Thus, the displacement can be increased. Immediately
That is, one end 2A of the cylinder 2 protrudes into the crank chamber side.
And a tunnel-type support hole 22 formed in the bearing wall 21.
And the end 2A on the entry side of the cylinder 2
To extend the cylinder length, and
Since the pair of recessed recesses 23 are formed in the support hole 22 of the crankcase 8, the crankshaft 8 is sequentially inserted into the support hole 22 of the bearing wall 21 from one side in the front-rear direction of the crankcase 2. Even when the swing radius R 'of the crankshaft 8 is set to be larger than the inner diameter of the support hole 22 when the crank arm 8 is incorporated in the crankcase 2, the pair of tips 8c of the crank arm 8 23, 23 can be passed through. As a result, the cylinder block
Increase crank radius without changing lock height
Engine exhaust due to piston stroke up
The amount can be increased.

[0015] (c) In the invention of claim 2, each of
A missing wall that lacks the lower part of the support hole 22 below the bearing wall 21
The lower half of the bearing housing 11 is formed in the left-right direction.
The right and left lower sides of each bearing wall 21 are fastened by fastening bolts 18
By fastening the half, the bearing box 11 is supported
So that it fits inside the hole 22 while being tightened from the left and right
, The bearing housing 11 is fitted inside the support hole 22.
In fixing, the bearing housing 11 is deviatedly rotated in the support hole 22
And the support hole 22 receives the upper half-arc portion.
Since the bearings are stopped, the concentric bearing accuracy of the bearing hole 12 is maintained at a high level.
You can have. Further, through the missing wall portion 23b,
Between the cylinders in the crankcase 20.
The waviness of the oil level due to the pumping action of the piston 15
Can be prevented.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. FIG. 1 (A) is a longitudinal sectional front view of a cylinder block, and FIG. 1 (B) is a longitudinal sectional side view of a main part of the cylinder block. This cylinder block 1 has the same basic configuration as that of the prior invention shown in FIG.

That is, in the cylinder block 1, a plurality of cylinders 2, a plurality of bearing walls 21 for supporting the crankcase 20 and the crankshaft 8 are integrally formed, and a tunnel-type support hole is formed in each of the bearing walls 21. Then, a bearing box 11 for pivotally supporting each intermediate journal 8a of the crankshaft 8 is fitted and fixed in each of the support holes 22, and one end 2A of the cylinder 2 is pushed into the crank chamber side. A pair of left and right cutout recesses 2c, 2c for avoiding interference with the connecting rod large end 17 are formed in the left and right neighboring parts 2a, 2a of the one end 2A of which the connecting rod large end 17 approaches.

Hereinafter, the characteristic structure of the cylinder block will be described. In the first embodiment, one end 2A of the cylinder 2 projects into the crank chamber side in a state of overlapping with a tunnel-type support hole 22 formed in the bearing wall 21 by a predetermined dimension D. That is, by extending the cylinder length by the dimension D at which the one end 2A of the cylinder 2 and the support hole 22 overlap, the contact area between the cylinder 2 and the piston skirt 15b at the bottom dead center of the piston 15 is increased. The slap noise of the piston 15 is suppressed while avoiding interference between the one end 2A of the cylinder 2 and the connecting rod large end 17.

In the first embodiment, as shown in FIG. 1 (A), a lower wall portion 23b is formed at the lower portion of each bearing wall 21 to cut off the lower portion of the support hole 22. The parts are fastened by fastening bolts 18. As shown in FIGS. 1 (A) and 1 (B), the fastening bolt 18 is mounted so as to penetrate the lower half of the bearing box 11 from side to side. Then, the bearing housing 11 is internally fitted and fixed in the support hole 22 in a state of being tightened from the left and right.

With the above configuration, the support hole 22 of the bearing wall 21
Even if is increased to some extent, the lower left and right halves of the bearing wall 21 are fastened with the fastening bolts 18, so that the insertion gap when the crankshaft 8 is assembled between the support hole 22 of the bearing wall 21 and the bearing box 11 is formed. Can be prevented from remaining. Also, the lower left and right halves of the bearing wall 21 are fastened by the fastening bolts 18 penetrating the bearing box 11, so that the bearing box 1
1 is prevented from eccentric rotation in the support hole 22 and the support hole 2
2 is received by the upper half-arc portion, so that the bearing housing 1
In fixing 1, the concentric bearing accuracy of the bearing hole 12 is maintained high. In the first embodiment, the missing wall 2
The cylinders in the crankcase 20 communicate with each other via 3b, so that the oil level rises due to the pumping action of the piston 15 and the oil temperature rises due to hitting the oil level S where the large connecting rod end 17 hits. Prevents excessive generation of mist.

FIG. 2 is a vertical sectional front view of a cylinder block according to Embodiment 2 of the present invention. In the second embodiment, in order to increase the displacement of the engine by increasing the stroke of the piston 15, the turning radius of each crank pin 8b of the crank shaft 8 shown in FIG. The swing radius R ′ is also set to be larger than the inner diameter of the support hole 22), and the support hole 2 formed in each bearing wall 21 in the cylinder block 1 of FIG.
A pair of upper and lower recesses 23 are formed in the upper portion 2 so as to be able to pass through a pair of crank arm tips 8c of the crankshaft 8 through the recesses 23. In the second embodiment, the missing wall portion 23
b corresponds to the lower recess 23. Other points are the same as those in FIG. 1 (Example 1).

In the second embodiment, a split bearing box 11 is assembled in advance to each intermediate journal 8a of the crankshaft 8, and the crankshaft 8 is inserted from the rear of the crankcase 2 into the support hole 22 of each bearing wall 21. And incorporated in the crankcase 2. At this time, the distal ends 8c of the crank arm having the larger swing radius R 'can pass through the corresponding recessed recesses 23. That is, by employing the above-described configuration, the stroke of the piston 15 can be increased without increasing the height of the cylinder block 1, and the engine displacement can be increased. In other words, without changing the engine displacement,
By reducing the inner diameter of the support hole 22 and the outer diameter of the bearing box 11, the height of the cylinder block 1 can be reduced and the engine can be downsized.

FIG. 3 is a longitudinal sectional front view of a cylinder block according to a third embodiment of the present invention. In the second embodiment, a pair of left and right slim recesses 23 is formed in support holes 22 formed in each bearing wall 21.
23 is formed. As shown in FIG. 3, the split bearing housing 11 is fixed with fixing bolts 19 in the same manner as the prior art example of FIG. The other points are the same as those in FIGS. 1 (Example 1) and 2 (Example 2).

In the second and third embodiments, as shown in FIGS. 2 and 3, a pair of
3 is an example of a four-cylinder engine (FIG. 6) for a crankshaft having a crank angle of 180 ° / 360 ° (FIG. 4), but the present invention is not limited to this, and the present invention is not limited to this. Engine crank angle is 120 ° / 24
Includes those intended for 0 ° and 230 ° crankshafts.
In the above embodiment, the crankshaft 8 is connected to the crankcase 2.
Although it is described that the crankshaft 8 is inserted through the support hole 22 of the bearing wall 21 sequentially from the rear of the crankcase 20, it is sufficient if the crankshaft 8 is inserted from any one side in the front-rear direction of the crankcase 20. Further, in the above-described embodiment, the diesel engine has been described as an example. However, it does not matter whether the engine is a diesel engine or a spark ignition engine.

[Brief description of the drawings]

1A and 1B show a first embodiment of the present invention, in which FIG. 1A is a vertical front view of a cylinder block, and FIG. 1B is a vertical side view of a main part of the cylinder block.

FIG. 2 is a diagram corresponding to FIG. 1A according to a second embodiment of the present invention.

FIG. 3 is a diagram corresponding to FIG. 1A according to a third embodiment of the present invention.

FIG. 4 is a perspective view of a crankshaft.

FIG. 5 is a diagram corresponding to FIG.

FIG. 6 is a side view showing a main part of the vertical water-cooled diesel engine in a cutaway manner.

[Explanation of symbols]

E: Multi-cylinder engine, 1 ... Cylinder block, 2 ... Cylinder, 2A ... One end of cylinder, 2a ... Right and left vicinity where the large end of the connecting rod approaches, 2c ... Notch recess, 8 ... Crankshaft, 8a ... Crankshaft Intermediate journal, 8c ... Crank arm tip, R '... Crank shaft swing radius, 11 ... Bearing box, 12 ... Bearing hole, 17 ... Connecting rod large end, 20 ... Crank case, 21 ... Bearing wall, 22 ... Support hole Reference numeral 23 denotes a recessed recess, and reference numeral 23b denotes a recessed recess (missing wall portion).

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobuhiro Yamamoto 64, Ishizukitamachi, Sakai City, Osaka Prefecture Inside Kubota Sakai Plant, Inc. (72) Inventor Hideyuki Koyama 64, Ishizukitamachi, Sakai City, Osaka Prefecture Inside Kubota Sakai Plant, Ltd. (72) Inventor Toshiyuki Yotsutsuji 64 Ishizu-Kitamachi, Sakai-shi, Osaka, Japan Inside Kubota Sakai Factory (72) Inventor Akira Hayaya 64, Ishizu-Kitacho, Sakai-shi, Osaka Prefecture Inside Kubota Sakai Factory, Inc. (72) Inventor Masahiko Sugimoto Ishizu, Sakai-shi, Osaka Kitamachi 64 Kubota Corporation Sakai Works (56) References JP-A-54-35509 (JP, A) JP-A-4-321176 (JP, A) JP-A 8-326600 (JP, A) -115619 (JP, U) Japanese Utility Model 1984-28650 (JP, U) Japanese Utility Model 2-40120 (JP, U) Japanese Utility Model Utility Model 3-29725 (JP, U) (58) Fields surveyed (Int. . ^7, DB name) F02F 1/00-7/00 F16C 3/22 F16C 9/02

Claims (2)

(57) [Claims] A plurality of cylinders (2), a crankcase (20), and a plurality of bearing walls (21) for supporting a crankshaft (8) are integrally formed, and each of said bearing walls (21) is Tunnel-shaped support holes (22) are formed, and a bearing box (11) for pivotally supporting each intermediate journal (8a) of the crankshaft (8) is fitted and fixed in each of the support holes (22). in a cylinder block of a multi-cylinder engine, is rush one end of the cylinder (2) and (2A) to the crank chamber side, inrush side end portion of the cylinder (2) (2A)
Right and left parts where the large end (17) of the connecting rod approaches
(2a) At (2a), the connecting rod large end (17)
(2c) (2c)
And a tunnel-shaped support hole (2) formed in the bearing wall (21).
2) and one end (2A) of the cylinder (2) on the entry side.
The swing radius (R ') of the crankshaft (8) is overlapped and
It is set larger than the inner diameter of the support hole (22) of the bearing wall (21).
And a pair of slacks in each of the support holes (22).
The recesses (23) and (23) are formed, and
3) A pair of clamps on the crankshaft (8) via (23)
(8c) (8c)
It forms a cylinder block of a multi-cylinder engine, characterized in that. 2. The cylinder block of a multi-cylinder engine according to claim 1, wherein each of said bearing walls (21) is provided below said support hole (22).
A missing wall portion (23b) lacking a portion is formed, and the bearing housing (1) is formed.
1) Fastening bolt (18) penetrating the lower half in the left-right direction
To fasten the lower left and right halves of each bearing wall (21).
Thus, the bearing housing (11) is left in the support hole (22).
It is configured to be fixed inside by tightening from the right,
A cylinder block for a multi-cylinder engine.