JPH0333460A - Crank shaft supporting device for engine - Google Patents

Abstract

PURPOSE:To reduce bending vibration by furnishing a plurality of bosses, which fastens a beam stretching in the crank axial direction, in such a way as upright at the bottom wall of a reinforcing structure, tying a plurality of bearing caps through this beam, and coupling the wall with the boss situated near it through ribs. CONSTITUTION:A plurality of bearing caps 34 are tied through a beam 33 stretching in the axial direction of a crank shaft 6. A plurality of bosses 27a-27f for fastening this beam 33 are provided upright on the bottom wall of a reinforcing structure 11 one after another in such a way as corresponding to the beam 33. Also at this bottom wall, coupling ribs 38, 39 are provided projectingly to connect that wall part of reinforcing structure 11 situated on the transmission side with the boss 27f located near the wall. Accordingly the bending stiffness is increased by these ribs 38, 39 on the back side of a cylinder block 2, while the coupling rigidity between the bosses 27a-27f is low on the front side of the ribs 38, 39, so that the bend up and down of the beam 33 is admitted and bending vibration reduced.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an engine crankshaft support device.

(Prior Art) In an engine-transmission system, that is, a power plant system, in which an engine and a transmission are connected in series with each other in the direction of the output shaft of the engine, generally, as shown in Japanese Patent Application Laid-Open No. 62-247158, The oil pan has its upper end surface coupled to the lower surface of the cylinder block, and its rear end surface coupled to the transmission case.

By the way, the above-mentioned power plant system can be regarded as a single elastic body, and in the power plant system, vibrations are generated in the direction perpendicular to the output shaft direction of the engine due to the vibrational force of the engine generated as the engine operates. Bending vibrations such as shaking are expected to occur. For this reason, conventionally, a frame-shaped reinforcing structure having a bottom wall inside is interposed between the cylinder block and the oil pan, and the reinforcing structure has a mating surface with the transmission case. The reinforcing structure is connected to the lower surface of the cylinder block as well as to the transmission case to increase the rigidity of the connection between the engine and the transmission.

(Problems to be Solved by the Invention) However, in the above structure, since the reinforcing structure must have a mating surface with the transmission case,
The mating surface has a certain length in the vertical direction, and the rigidity of the connection portion between the mating surface portion of the reinforcing structure and the bottom of the reinforcing structure must be low. For this reason, in the current situation where engines are increasing in output and rotation speed, it is not always possible to obtain sufficiently satisfactory results in suppressing bending vibrations in power plant systems.

Further, in the above-mentioned reinforcing structure, bearing caps are provided so as to straddle both side wall portions of the reinforcing structure, and the both side wall portions function as bearing beams. For this reason, since both side walls of the reinforcing structure are attached to the lower end of the cylinder block, the reinforcing structure is extremely strongly restrained in bending, and the mV resistance of the crankshaft (journal part) to the bearing cap is considerably large. I have no choice but to do so.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an engine crankshaft support device capable of reducing bending vibration of the engine/transmission system and reducing mechanical resistance of the crankshaft relative to the bearing cap. Our goal is to provide the following.

(Means and operations for solving the problem) In order to achieve the above object, in the present invention, a cylinder block and a transmission are connected in series in the axial direction of the crankshaft, and the lower end of the cylinder block and the transmission are coupled in series in the axial direction of the crankshaft. A frame-shaped reinforcing structure having a bottom wall inside is coupled to the transmission, and a plurality of bearing caps are arranged in the axial direction of the crankshaft in a space above the reinforcing structure. In the crankshaft support device, the plurality of bearing caps are connected via a beam extending in the axial direction of the crankshaft, and a plurality of boss portions for fastening the beams are provided on a bottom wall portion of the reinforcing structure. The bottom wall of the reinforcing structure includes a wall on the transmission side of the reinforcing structure and a boss on the side closer to the wall. A connecting rib is provided in a protruding manner to connect the connecting ribs, and the bending rigidity between the connecting ribs in the crankshaft axial direction is set to be greater than that between the other boss portions.

With the above configuration, on the rear side of the cylinder block (transmission side), the bending rigidity is increased by the connecting rib, but on the front side of the cylinder block, the connecting rigidity between each boss part is lower than the connecting rib, so the beam Bending (bending) in the vertical direction is allowed to some extent. Therefore, it is possible to reduce the bending vibration of the engine transmission system, and also to reduce the mechanical resistance of the crankshaft relative to the bearing cap.

(Example) Embodiments of the present invention will be described below based on the drawings.

In FIGS. 1 to 5, l is a V-type engine, and its cylinder block 2 has a pair of left and right banks 3.4. This cylinder block 2 has a skirt portion 5 as a crankcase component and a bearing portion 7 for a crankshaft 6. The inner space of the skirt portion 5 is used as a crank chamber, and the bearing portion 7 is located on the front side of the cylinder block 2 (because this is a V type 6-cylinder engine).
Four bearing portions 7a to 7d are provided from the left side in FIG. 2 to the rear side (the right side in FIG. 2). As shown in FIG. 3, a mounting surface 8 is formed on the rear surface of the cylinder block 2 at its outer peripheral edge.
A plurality of fastening holes 9 for attaching the transmission case are formed in the. By using this fastening hole 9 and bolt,
A transmission case 10 (transmission) is coupled to the rear surface of the cylinder block 2.

At this time, the lower part of the mission case 10 is supposed to protrude below the lower end of the cylinder block 2, as shown in FIG.

As shown in FIGS. 1 to 3, a lower block 1 as a frame-shaped reinforcing structure is provided at the lower end of the skirt portion 5 of the cylinder block 2 and the lower portion of the mission case 10.
1 are combined. As shown in FIGS. 4 and 5, the lower block 11 has side wall portions 12a and 12 facing each other.
b, and a front wall portion (left wall portion in FIGS. 4 and 5) 1 that connects both side wall portions 12a and 12b at both ends in the longitudinal direction of the side wall portion.
3, a rear wall portion (the right wall portion in FIGS. 4 and 5) 14, and a bottom wall portion 15.

The upper end surfaces of the side wall portions 12a, 12b serve as mounting surfaces 16a, 16b for the lower end of the side wall of the cylinder block 2, and fastening holes 17a, 17b are provided at regular intervals on both mounting surfaces 16a, 16b. is opened. By using these fastening holes 17a, 17b and bolts 18, as shown in FIG.
The upper ends of 2a and 12b are connected to the lower end of the side wall of the cylinder block 2.

As shown in FIGS. 4 and 5, the front and rear wall portions 13 and 14 have their respective upper end surfaces forming mounting surfaces 19 and 20 for the lower ends of the front and rear walls of the cylinder block 2. Each mounting surface 19.20 is continuous with the mounting surfaces 16a, 16b, and each mounting surface 19.20 also has a fastening hole 21.
22 are formed at regular intervals. Each fastening hole 21
．． 22 and bolts 23, the upper end surfaces of the front and rear walls 13, 14 are connected to the lower ends of the front and rear walls of the cylinder block 2, as shown in FIG.

As shown in FIG. 3 to FIG.
Cylinder block 2 protrudes from both sides from 2a and 12b.
It is formed in a substantially semicircular shape when viewed from the rear side, and an internal space 24 is formed on the outer surface side. The outer surface of this rear wall portion 14 has a mission case 10 at its outer peripheral edge.
A mounting surface 25 for the lower portion is formed, and the mounting surface 25 is flush with the mounting surface 8 on the rear surface of the cylinder block 2. A plurality of fastening holes 26 for mounting the mission case are formed at regular intervals on the mounting surface 25, and the rear wall portion 14 is connected to the lower part of the mission case 10 by using each of the fastening holes 26 and bolts. ing.

As shown in FIGS. 4 and 5, the bottom wall portion 15 is disposed within the lower block 11 so as to partition the interior of the lower block 11 into upper and lower sections. This bottom wall portion 15 has a plurality of boss portions 27a to 2 that are close to the side wall portion 12a.
7f is erected, and a plurality of boss portions 28a to 28f are erected so as to approach the side wall portion 12b,
These boss portions 27a to 27f, 28a to 28f are arranged at predetermined intervals along each side wall portion 12a, 12b. Among these, between the boss portions 27a to 27e and the side wall portion 12a, a rib 29a is provided at the bottom so as to connect each boss portion 27a to 27e and the fastening hole 17a near each boss portion 27a to 27e. The ribs 30a protrude from the wall portion 15, and in particular, for the boss portion 27a, a rib 30a is provided on the bottom wall so as to connect the boss portion 27a and the fastening hole 21 of the front wall portion 13 in front of the boss portion 27a. It is provided protrudingly from the portion 15.

On the other hand, between the boss parts 28a to 28e (111 wall part 12b), each boss part 28a to 28e and each boss part 2
A rib 29b protrudes from the bottom wall portion 15 so as to connect the fastening holes 17b near the ribs 8a to 28e.
Regarding the boss portion 28a, the boss portion 28a and the boss portion 2
A rib 30b protrudes from the bottom wall 15 so as to connect the fastening hole 21 of the front wall 13 in front of the rib 30b. In addition, in FIG. 4, 31 is a mounting hole for an oil pan.

A bearing member 32 is provided on the boss portions 27a-27f, 28a-28f, as shown in FIGS. 1-3. This bearing member 32 consists of a paired beam 33 and a plurality of bearing caps 34, and in this embodiment, the bearing beam 33 and the plurality of bearing caps 34 are integrally formed. Of course, the bearing beam and the plurality of bearing caps may be formed separately and fixed using fasteners such as bolts.

The bearing beam 33 includes the boss portions 27a to 27.
A pair of connecting portions 35a, 35b provided at the upper end of the f group and the upper ends of the boss portions 28a to 28f groups, respectively, and a plurality of bridge portions 36 spanning the pair of connecting portions 35a, 35b (the bridge portions 36 are In the bearing beam 33
Since the bearing cap 34 and the bearing cap 34 are integrally formed, the bearing cap 34 and the bearing cap 34 are integrally formed. a pair of connecting parts 35a,
35b is connected to each boss part 27a to 27f by a bolt 37 screwed into each boss part 27a to 27f, 28a to 28f from below.
7r and 28a to 28f groups, respectively, and at this time, the pair of connecting portions 35a and 35b extend in the longitudinal direction of the cylinder block 2 (in the axial direction of the crankshaft 6). . Two of the plurality of bridge parts 36 are arranged below each of the bearing parts 7F3P to 7d of the cylinder block 2, respectively, and each of the bridge parts 36 is arranged as shown in FIG. As shown in FIG. 3, the shape is convex upward. This allows each bridge portion 36 to bend to some extent against vertical bending loads (C explosion loads).

The plurality of bearing caps 34 are provided on each of the two front notch portions 36, and each bearing cap 34 and each bearing portion 7a of the cylinder block 2
7d cooperate with each other to rotatably support the crankshaft 6.

The bottom wall portion 15 of the lower block 11 has markings shown in FIGS. 2 to 5.
As shown in the figure, connecting ribs 38 and 39 are provided in a protruding manner. As shown in FIGS. 4 and 5, the connecting ribs 38 are arranged on the upper surface of the bottom wall 15 so as to connect between the boss 28f and the rear wall 14, and are connected between the two. The ribs 38 extend in the axial direction of the crankshaft 6. The connecting ribs 39 are arranged in the inner space 24 of the rear wall 14 in correspondence with the connecting ribs 38, and each of the connecting ribs 39 is arranged in the inner space 24 of the rear wall 14.
4 and the outer circumferential edge below the upper end thereof, and extends from the rear wall 14 toward the respective bosses 27f and 28f on the lower surface side of the bottom wall 15.

An oil pan 40 is attached to the lower surface of the lower block 11. The oil pan 40 is disposed near the front side of the cylinder block 2, and its installation is carried out through the respective fastening holes 17a, 17b, 21 in the side walls 12a, 12b and front wall 13 of the lower block 11, and through the oil pan installation. Hole 31
, by using the bolts 23 and 41.

Therefore, in the above crankshaft support device, the connecting ribs 38 and 39 increase the bending rigidity of the transmission case 10 side, making it possible to reduce bending vibrations of the engine/transmission system.

On the other hand, in this embodiment, on the front side of the cylinder block 2 than the bosses 27f and 28f, the bosses 27a to 28f are
No ribs are provided between 27e and 28a to 28e, and the bending rigidity is not increased on the mission case 10 side at that portion. Therefore, bending (bending) of the bearing beam 33 in the vertical direction is allowed to some extent, and along with this, bending of the crankshaft 6 is also allowed, reducing the mechanical resistance of the crankshaft 6 against the bearing cap 34. This means that it can be reduced.

(Effect of the invention)

Claims (1)

[Claims] (1) A cylinder block and a transmission are coupled in series in the axial direction of the crankshaft, a frame-like reinforcing structure having an internal bottom wall portion is coupled to the lower end of the cylinder block and the transmission, and the In an engine crankshaft support device in which a plurality of bearing caps are sequentially arranged in the axial direction of the crankshaft in a space above the reinforcing structure, the plurality of bearing caps are connected to each other via a beam extending in the axial direction of the crankshaft. a plurality of bosses for fastening the beams are sequentially erected on the bottom wall of the reinforcing structure in a direction in which the beams extend in correspondence with the beams, and the bottom wall of the reinforcing structure A connecting rib is provided in the portion so as to protrude so as to connect the wall portion on the transmission side of the reinforcing structure and the boss portion on the side closer to the wall portion, and the connecting rib is provided to prevent bending in the crankshaft axial direction between the connecting ribs. A crankshaft support device for an engine, characterized in that the rigidity is set to be greater than that between the other boss portions.