JP3075198B2 - Ladder frame - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ladder frame, and more particularly, to a ladder frame that holds a journal portion of a crankshaft together with a cylinder block when assembled to a cylinder block of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Utility Model Laid-Open No. 5-58860.
Ladder frames are known, as disclosed in US Pat.
FIG. 5 shows a plan view of the conventional ladder frame 10. The ladder frame 10 includes a plurality of bearing cap portions 12 and side wall portions 14 and 16 connecting the bearing cap portions 12 at both ends thereof.

[0003] The bearing cap portion 12 has a bearing portion 18 formed in a semicircular shape at a central portion thereof, and has bolt holes 20 on both sides of the bearing portion 18. After the crankshaft is assembled to the cylinder block of the internal combustion engine, the ladder frame 10 is assembled to the cylinder block from below. The bolt holes 20 are through holes for inserting bolts for fixing the ladder frame 10 to the cylinder block.

[0004] The same semicircular bearing portion as the bearing portion 18 is formed in the cylinder block at a position facing the bearing portion 18 of the bearing cap portion 12.
The journal part of the crankshaft is rotatably held by the bearing part of the cylinder block and the bearing part 18 of the bearing cap part 12.

The conventional ladder frame 10 is provided with two knock pins 22 at a pair of diagonals. The knock pin 22 fits into a pin hole provided at a predetermined position of the cylinder block when the ladder frame 10 is assembled to the cylinder block. When the knock pin 22 is used in this manner, the positioning between the ladder frame 10 and the cylinder block can be accurately performed.

[0006]

A large stress is transmitted to the bearing cap portion 12 of the ladder frame 10 via the crankshaft during operation of the internal combustion engine. Therefore, the stress acting on the bearing portion 18 of the bearing cap portion 12 to deform the semicircular shape during the operation of the internal combustion engine, or the stress causing the relative position of the cylinder block to the bearing portion to be displaced. Works.

In the conventional ladder frame 10 described above,
Except for the two bearing cap portions 12 provided at both ends, the three bearing cap portions 12 are not provided with knock pins for restricting relative displacement with respect to the cylinder block. Therefore, these bearing cap portions 1
In the case of No. 2, when the above-mentioned stress is applied, deformation or relative displacement with respect to the cylinder block is likely to occur.

In the conventional ladder frame 10 described above,
The two bearing cap portions 12 provided at both ends are provided with knock pins 22 for restricting relative displacement with respect to the cylinder block. The knock pin 22 is effective in preventing the bearing portion 18 of the bearing cap portion 12 from being displaced relative to the cylinder block when the above-described stress acts on the bearing cap portion 12.

FIG. 6 is a cross-sectional view of the bearing block 12 and the cylinder block 24 whose relative displacement is restricted by the knock pin 22. A bearing portion 18 indicated by a solid line in FIG. 6 shows a shape when the above-mentioned stress is not applied to the bearing cap portion 12 located at the end of the ladder frame 10. Further, a bearing portion 18 'indicated by a broken line in FIG. 6 shows a shape when the above-mentioned stress acts on the bearing cap portion 12.

As shown in FIG. 6, when the knock pin 22 is provided, the relative displacement between the bearing cap portion 12 and the cylinder block 24 can be restricted in the vicinity of the provided portion. However, merely arranging the knock pin 22 on one side of the bearing portion 18 cannot control the deformation of the other side of the bearing portion 18. For this reason, it is difficult to restrict the deformation and relative displacement of the bearing portion 18 strictly with the above-described conventional ladder frame 10.

In the conventional ladder frame 10 described above,
In order to strictly restrict the deformation and the relative displacement in all the bearing parts 18, all the bearing cap parts 1
For 2, it is effective to arrange knock pins on both sides of the bearing portion 18. However, according to such a structure,
There are adverse effects such as an increase in the number of parts and a deterioration in assemblability between the ladder frame 10 and the cylinder block.

The present invention has been made in view of the above points, and strictly suppresses the deformation and relative displacement of all bearing portions while suppressing the occurrence of adverse effects such as deterioration of assemblability and increase in the number of parts. An object is to provide a ladder frame that can be regulated.

[0013]

The above object is achieved by the present invention.
As described in the above, in a ladder frame including a plurality of bearing cap portions having a bearing portion for holding a journal portion of a crankshaft, and both side wall portions connecting the plurality of bearing cap portions at both ends thereof, Ribs for connecting a plurality of bearing cap portions inside the side wall portions; and a rib on both sides of the bearing portion of the bearing cap portion disposed at a position sandwiching the two bearing cap portions among the plurality of bearing cap portions. And a knock pin to be provided.

In the present invention, knock pins are provided on both sides of the bearing portion in some bearing caps. The bearing cap portion in which the knock pins are arranged on both sides of the bearing portion shows high rigidity after the ladder frame is assembled to the cylinder block. On one side of the bearing cap portion on which the knock pin is not provided, a bearing cap portion on which the knock pin is provided is always disposed. The bearing cap portion where the knock pin is not provided and the bearing cap portion where the knock pin is provided are connected by a rib. For this reason, high rigidity is also provided to the bearing cap portion where the knock pin is not provided.

Further, the above object is achieved by providing a plurality of bearing caps having a bearing portion for holding a journal portion of a crankshaft and the plurality of bearing caps at both ends thereof. In a ladder frame including two side wall portions to be connected, a rib connecting the plurality of bearing cap portions inside the both side wall portions, and a center axis line of the bearing portion, the ribs being disposed on adjacent bearing cap portions. And a knock pin disposed on one side of the bearing portion of the plurality of bearing cap portions so as to be alternately positioned with the ladder frame interposed therebetween.

In the present invention, all the bearing caps are provided with knock pins on one side of the bearing portion. Further, these knock pins are alternately arranged with the center axis of the bearing portion interposed therebetween. After the ladder frame is fixed to the cylinder block, all the bearing cap parts show high rigidity on the side provided with the knock pin. On the other hand, the side of all the bearing caps on which the knock pin is not provided is connected to the side of the adjacent bearing cap on which the knock pin is provided via a rib. For this reason, all the bearing cap parts exhibit high rigidity on both sides of the bearing part.

[0017]

FIG. 1 is a plan view of a ladder frame 30 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view obtained when the ladder frame 30 of the present embodiment is cut along the line II-II shown in FIG.

The ladder frame 30 is a component of a four-cylinder internal combustion engine. The ladder frame 30 is used while being fixed to a cylinder block (not shown) of the internal combustion engine. The ladder frame 30 includes first to fifth bearing cap portions 32 _{-1 to} 32 _-5 . The first to fifth bearing cap portions 32 _{-1 to} 32 _-5 are connected by side walls 34 and 36 at both ends.

First to fifth bearing cap portions 32 _-1
The to 32 _-5 central portion of the bearing portion 38 of each semi-circular shape is formed. Bolt holes 40 are provided on both sides of the bearing portion 38. Ladder frame 3
0 is fixed to the cylinder block of the internal combustion engine by a bolt inserted into the bolt hole 40.

The cylinder block of the internal combustion engine has a first
To fifth bearing cap 32_-1~ 32_-FiveBearing part
The same semicircle as the bearing part 38 at the position facing the minute 38
A shaped bearing portion is formed. 1st to 5th barely
Cap 32_-1~ 32 _-FiveBearing part 38
Crank not shown together with the bearing part of the cylinder block
The journal of the shaft is rotatably held.

The first to fifth ladder frames 30 have
Bearing cap 32_-1~ 32 _-FiveOf the two
Bearing installed at the position sandwiching the ring cap
Specifically, the cap portion is numbered 2 from the left in FIG.
Second bearing cap portion 32 located at the eye_-2, And
And the fifth bearing key located on the rightmost side in FIG.
Cap part 32_-FiveIs provided with a knock pin 42.
You. The knock pin 42 is connected to the second and fifth bearing carriers.
Tap 32_-2, 32_-FiveOn both sides of the bearing portion 38
Have been.

The cylinder block of the internal combustion engine has a fitting hole at a position corresponding to the knock pin 42 provided on the ladder frame 30. The ladder frame 30 is assembled to the cylinder block so that the knock pins 42 fit into the fitting holes. The knock pin 42 is fitted without looseness into the fitting hole of the cylinder block. Therefore, if the knock pin 42 is interposed, the ladder frame 30 and the cylinder block can be accurately positioned.

The ladder frame 30 includes first to fourth ribs 44 _{-1 to} 44 _-4 for connecting mutually adjacent ones of the first to fifth bearing cap portions 32 _{-1 to} 32 _-5.
It has. The first to fourth ribs 44 _{-1 to} 44 _-4 are provided inside the side walls 34 and 36. A space between two adjacent bearing cap portions is used as a space for rotating a crankpin and a counterweight of a crankshaft. First to fourth ribs 44 _-1
~ 44 _-4 , so that they do not interfere with the crankpin and counter weight with the rotation of the crankshaft,
Further, the ladder frame 30 is provided in a curved shape having a surface substantially parallel to a mounting surface to the cylinder block so as to suppress lateral deformation of the ladder frame 30.

First to fifth bearers of ladder frame 30
Cap 32_-1~ 32_-FiveDuring the operation of the internal combustion engine
A large stress is transmitted through the crankshaft.
When such stress is input, the first to fifth bearings
Cap 32_-1~ 32 _-FiveDeformation or relative displacement
When this occurs, the crankshaft in the bearing portion 38
The sliding resistance increases. Therefore, the first to fifth bearings
G cap part 32_-1~ 32_-FiveMust have high rigidity
And is appropriate.

[0025] In the ladder frame 30, the second bearing cap section 32 _-2, bearing portion 38 as described above
The knock pins 42 are provided on both sides of the. For this reason,
When the ladder frame 30 is assembled to the cylinder block, the deformation of the second bearing cap section 32 _2, and a relative displacement with respect to the second bearing cap section 32 _-2 cylinder block is regulated by both sides of the bearing portion 38 . Thus both sides of the bearing portion 38, when the deformation and relative displacement is regulated, the second bearing cap section 32 _-2 exhibits high rigidity against stress transmitted from the crankshaft.

As described above, the fifth bearing cap 3
The 2 _-5, knock pin 42 is disposed on either side of the second bearing cap section 32 _-2 Like the bearing portion 38. Thus, the fifth bearing cap section 32 _-5, like the second bearing cap section 32 _-2, exhibits high rigidity against stress transmitted from the crankshaft.

In the ladder frame 30 of this embodiment,
First, third, and fourth bearing cap portions _32-1,3
The knock pins 42 are not provided at 2 _-3 and 32 _-4 .
Therefore, even the ladder frame 30 is assembled to the cylinder block, the first, third and fourth bearing cap section 32 _-1, 32 _-3, the rigidity of the 32 _-3, second or fifth bearing cap section described above There is no improvement based on the same principle as 32 _-2 and 32 _-5 .

However, the first bearing cap 3
2 _-1 and the third bearing cap portion 32 _-3 are respectively connected via the first rib _44-1 or the second rib _44-2 .
Is connected to the second bearing cap section 32 _-2 exhibits high rigidity. Further, the fourth bearing cap portion 32
_-4 through a fourth rib 44 _-4, it is connected to the fifth bearing cap section 32 _-5 showing a high rigidity. Therefore, when the ladder frame 30 is assembled to the cylinder block, the second and fifth bearing caps 3
As with 2 _-2 and 32 _-5 , high rigidity is ensured also for the first, third and fourth bearing cap portions _32-1 , 32 _-3 and 32 _-4 .

As described above, the ladder frame 3 of this embodiment is
0, the second and fifth bearing cap portions 32
_A high rigidity is provided to all of the first to fifth bearing cap portions 32 _{-1 to} 32 _-5 simply by arranging a total of four knock pins 42 on both sides of the bearing portions 38 of the _-2 and 32 _-5. Can be. Therefore, according to the ladder frame 30 of the present embodiment, it is possible to strictly restrict the deformation and the relative displacement of all the bearing portions 38 without causing inconveniences such as an increase in the number of parts and a deterioration in assemblability.

In the above embodiment, the first to fourth ribs 44 _{-1 to} 44 _-4 are "ribs" according to the first aspect.
In addition, the second and fifth bearing cap portions 32 _-2 , 32
_-5 corresponds to the "bearing cap portion disposed at a position sandwiching the two bearing cap portions" of the first aspect.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows a plan view of a ladder frame 50 according to a second embodiment of the present invention. The ladder frame 50 is a member used as a component of a five-cylinder internal combustion engine. 3 that are substantially the same as the components shown in FIG. 1 are denoted by the same reference numerals and description thereof will be omitted or simplified.

The ladder frame 50 is provided with a sixth bearing cap section 32 _-6 in addition to the first to fifth bearing cap section 32 _-1 to 32 _-5. The first to sixth bearing cap portions 32 _{-1 to} 32 _-6 are connected at their both ends by side wall portions 52 and 54.

[0033] The sixth bearing cap section 32 _-6, similarly to the first bearing cap section 32 _-1 to 32 _-5 bearing portion 38 and bolt hole 40 is formed. Also,
The sixth bearing cap section 32 _-6 is coupled to the fifth bearing cap section 32 _-5 through the fifth rib 44 _-5.

In the ladder frame 50, the knock pins 42 are provided on both sides of the bearing portion 38 of the second bearing cap portion 32 _-2 and the fifth bearing cap portion _32-5 as in the case of the first embodiment described above. It is arranged. Therefore, when the ladder frame 50 is assembled to the cylinder block, the first to fifth bearing cap portions 32 _{-1 to} 32 _-5 receive stress transmitted from the crankshaft in the same manner as in the first embodiment described above. High rigidity.

In the ladder frame 50, the sixth
Bearing cap section 32 _-6 through the fifth rib 44 _-5, is connected to the fifth bearing cap section 32 _-5 showing a high rigidity. Therefore, the ladder frame 50 is assembled to the cylinder block, like the first to fifth bearing cap section 32 _-1 to 32 _-5, high rigidity sixth bearing cap section 32 _-6 is ensured.

As described above, the ladder frame 5 of this embodiment is
0, the second and fifth bearing cap portions 32
_A high rigidity is imparted to all of the first to sixth bearing cap portions 32 _{-1 to} 32 _-6 by merely arranging a total of four knock pins 42 on both sides of the bearing portions 38 of _-2 and 32 _-5. Can be. Therefore, according to the ladder frame 50 of the present embodiment, it is possible to strictly restrict the deformation and the relative displacement of all the bearing portions 38 without causing inconveniences such as an increase in the number of parts and a deterioration in assemblability.

In the above embodiment, the first to fifth ribs 44 _{-1 to} 44 _-5 are the "ribs" according to the first aspect.
In addition, the second and fifth bearing cap portions 32 _-2 , 32
_-5 corresponds to the "bearing cap portion disposed at a position sandwiching the two bearing cap portions" of the first aspect.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a plan view of a ladder frame 60 according to a third embodiment of the present invention. The ladder frame 60 is a member used as a component of a four-cylinder internal combustion engine. 4 that are substantially the same as the components shown in FIG. 1 are denoted by the same reference numerals and description thereof will be omitted or simplified.

The ladder frame 60 has knock pins 62 _{-1 to} 62 _-5 on the first to fifth bearing cap portions 32 _{-1 to} 32 _-5 , respectively. Knock pin 6
2 _{-1 to} 62 _-5 are arranged in bearing cap portions 32 _{-1 to} 32 _-5 adjacent to each other, and the bearing portion 3
8 are arranged so as to be alternately arranged with respect to the center axis of the reference numeral 8.

[0040] In the ladder frame 60, the side knock pin 62 _-1 of the first bearing cap section 32 _-1 is not disposed (hereinafter, referred to as non-knock pin side), the first
Second side knock pin 62 _-2 bearing cap portion 32 _-2 are arranged (hereinafter, the knock pin side hereinafter) via the ribs 44 _-1 is connected to. Similarly, non-knock pin side of the second to fifth bearing cap section 32 _-2 to 32 _-5, first through via the fourth rib 44 _-1 to 44 _-4, knock pin of the bearing cap portion adjacent thereto It is connected to the side.

According to the above configuration, the ladder frame 60
If but assembled to the cylinder block, the knock pin side of the first to fifth bearing cap section 32 _-1 to 32 _-5, due to the knock pin 62 _-1 to 62 _-5 is arranged High rigidity is directly ensured. Also, the first to fifth bearing cap portions 32 _{-1 to} 32 _-5
The non-knock pin side is indirectly secured with high rigidity due to being connected to the knock pin side of the adjacent bearing cap portion.

As described above, the ladder frame 6 of this embodiment is
0, the first to fifth bearing cap portions 32 _-1
３２32 _-5 , one by one knock pin 32 _-1 ３２32 _-5
By simply disposing, it is possible to impart high rigidity to all of the first to fifth bearing cap portions 32 _{-1 to} 32 _-5 . Therefore, according to the ladder frame 60 of the present embodiment, it is possible to strictly restrict the deformation and the relative displacement of all the bearing portions 38 without causing inconveniences such as an increase in the number of parts and a deterioration in assemblability.

In the above embodiment, the first to fourth ribs 44 _{-1 to} 44 _-4 correspond to the "rib" according to the second aspect.

[0044]

As described above, according to the first and second aspects of the present invention, all of the bearing caps can be provided without disposing the knock pins on both sides of the bearing portions of all of the bearing cap portions. High rigidity can be imparted to the portion. Therefore, according to the ladder frame according to the first aspect and the ladder frame according to the second aspect, it is possible to suppress an adverse effect such as an increase in the number of parts and a deterioration in assemblability.
Deformation and relative displacement of all bearing parts can be strictly regulated.

[Brief description of the drawings]

FIG. 1 is a plan view of a ladder frame according to an embodiment of the present invention.

FIG. 2 shows a ladder frame of this embodiment as shown in FIG.
It is sectional drawing obtained by cutting | disconnecting along a straight line.

FIG. 3 is a plan view of a ladder frame according to a second embodiment of the present invention.

FIG. 4 is a plan view of a ladder frame according to a third embodiment of the present invention.

FIG. 5 is a plan view of a conventional ladder frame.

FIG. 6 is a diagram illustrating a state of deformation occurring when stress is applied to a conventional ladder frame via a crankshaft.

[Explanation of symbols]

30, 50, 60 ladder frame 32 _-1 first bearing cap 32 _-2 second bearing cap 32 _-3 third bearing cap _32-4 fourth bearing cap 32 _-5 fifth bearing cap 32 _-6 sixth bearing cap 34 , 36, 52, 54 Side wall part 38 Bearing part 42, 62 _{-1 to} 62 _-5 Dowel pin 44 _-1 First rib 44 _-2 Second rib 44 _-3 Third rib 44 _-4 Fourth rib 44 _-5 Fifth rib

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02F 7/00 301 F16C 9/02

Claims (2)

(57) [Claims] 1. A ladder frame comprising: a plurality of bearing caps having a bearing portion for holding a journal of a crankshaft; and both side walls connecting the plurality of bearing caps at both ends thereof. A rib connecting the plurality of bearing caps inside the side wall portions; and a rib on both sides of the bearing portion of the bearing cap portion disposed at a position sandwiching the two bearing cap portions among the plurality of bearing cap portions. A rudder frame, comprising: a knock pin to be provided; 2. A ladder frame comprising: a plurality of bearing caps having a bearing portion for holding a journal of a crankshaft; and both side walls connecting the plurality of bearing caps at both ends thereof. A plurality of ribs connecting the plurality of bearing cap portions inside the side wall portions; and a plurality of ribs arranged on adjacent bearing cap portions so as to alternately interpose the center axis of the bearing portion. A dowel pin disposed on one side of the bearing portion of the bearing cap portion.