JP5097071B2 - Bearing cap structure - Google Patents

Description

  The present invention relates to a structure of a bearing cap that supports a crankshaft in an automobile engine.

Conventionally, in the structure of a bearing cap in an automobile engine, in order to improve the rigidity of the entire engine, a plurality of bearing cap portions are provided by bearing beam portions (connection wall portions) extending in the axial direction (front-rear direction) of the crankshaft. , There is a structure connected to each other.
This structure remarkably improves the rigidity of the entire engine as compared with the structure in which the bearing cap portions are individually independent.

  However, in the conventional bearing cap structure, since the plurality of bearing cap portions are connected by the bearing beam portion, there is a problem that the weight of the entire engine increases. In order to solve this problem, it is conceivable to form a lightening portion in the bearing cap portion. As such a technique, conventionally, the width of the lower portion is made larger than the width of the upper portion of the bearing cap portion, and the lightening portion is removed. What forms a part is known (refer patent document 1).

Japanese Utility Model Publication No.59-114439 (FIG. 8)

  However, in the above-described technology, the width of the lower portion is made larger than the width of the upper portion of the bearing cap portion to form the lightening portion, so that the entire bearing cap is increased in size, resulting in an increase in weight. .

  Accordingly, an object of the present invention is to provide a bearing cap structure that can reduce the weight of the entire engine without reducing the rigidity of the entire engine and without increasing the size of the entire bearing cap.

The present invention includes a plurality of bearing cap portions fixed to a lower side of a cylinder block and having a support surface portion that rotatably supports a journal portion of a crankshaft, and these bearing cap portions are connected to each other in the axial direction of the crankshaft. A bearing cap structure comprising a bearing beam portion to be formed, and on both sides of the support surface portion of the bearing cap portion, bolt mounting holes for attaching the bearing cap portion to the cylinder block are penetrated and drilled. From the lower side of the bearing cap portion, a lightening portion is formed within the axial width of the crankshaft of the support surface portion, and the crankshaft is on both sides of the lightening portion and outside the bolt mounting hole. A pair of outer peripheral links that extend in the axial direction of the shaft and connect the bearing cap portions. There are formed, on the outer side of the bolt mounting holes an inner of the outer peripheral rib, said extending along the outer peripheral rib, straight rib connecting the respective bearing cap portion is formed, the outer peripheral ribs, said plurality Directly connected to the bolt mounting portion of the bolt mounting hole provided at the end of the bearing cap portion in the axial center of the crankshaft of the bearing cap portion , between the linear rib and the outer peripheral rib, A pair of ribs is provided at an end of the bearing cap portion adjacent to one side of the bearing cap portion at the side of the bolt mounting hole and in the axial center of the crankshaft among the plurality of bearing cap portions , and the plurality of bearing caps. The bearing is located at the center in the axial direction of the crankshaft rather than the bearing cap at the center in the axial direction of the crankshaft. Towards the bearing cap portion adjacent to one side of Gukyappu portion, characterized in that it is widely formed in the direction perpendicular to the axial direction of the crankshaft.

In the present invention, it is preferable that the pair of ribs are provided in a C shape so as to be separated from each other toward the outer peripheral rib side from the linear rib side.

  ADVANTAGE OF THE INVENTION According to this invention, the bearing cap structure which enables weight reduction of the whole engine, without reducing the rigidity of the whole engine and enlarging the whole bearing cap can be provided.

[Reference example]
Hereinafter, the details of the bearing cap structure according to the reference example will be described with reference to the drawings. In the drawings to be referred to, FIG. 1 is a perspective view of an engine to which a bearing cap according to a reference example is applied, and FIG. 2 is an exploded perspective view of the engine shown in FIG.

  As shown in FIG. 1, the engine 1 is an SOHC (single overhead camshaft) type in-line four-cylinder engine. A cylinder head 3 and a cylinder head cover 4 are sequentially joined to the upper end of the cylinder block 2. An oil pan 5 is joined to the lower end. A chain case 6 is attached to one end of the engine 1 so as to straddle the cylinder block 2 and the cylinder head 3.

  As shown in FIG. 2, the cylinder block 2 has four cylinder bores 2A arranged in a row, and a piston 9 connected to a crankshaft 7 via a connecting rod 8 slides in each cylinder bore 2A. It can be inserted freely. The crankshaft 7 is attached to the lower portion of the cylinder block 2 in a state where the journal portion 7A is rotatably supported by the bearing cap 10. An oil pump 11, a crank sprocket 12, and a crank pulley 13 are attached to one end portion of the crankshaft 7 protruding from the cylinder block 2.

  A camshaft 14 is rotatably supported and accommodated in an upper space of the cylinder head 3 covered with the cylinder head cover 4. One end of the camshaft 14 protrudes from one end of the cylinder head 3, and a cam sprocket 15 is fixed to the one end. A timing chain 16 is wound between the cam sprocket 15 at one end of the camshaft 14 and the crank sprocket 12 at one end of the crankshaft 7, as shown in FIG. A transmission mechanism from the shaft 7 to the camshaft 14 is configured. As shown in FIG. 1, the engine 1 is provided with a compressor 18 and an AC generator 19 for an air conditioner driven by a crank pulley 13 via a belt 17.

  As shown in FIG. 3, the bearing cap 10 includes five bearing cap portions 10A, 10A,... That rotatably support the five journal portions 7A, 7A,. Of the bearing caps 10A, 10A,... Are connected to each other in the front-rear direction. Here, the “front-rear direction” refers to a direction along the axial direction of the crankshaft 7, and the side on which the chain case 6 is attached to the cylinder block 2 is the front and the opposite side is the rear.

  The bearing cap portion 10A has a semicircular support surface portion 10C so that the upper center of the bearing cap portion 10A can rotatably support the journal portion 7A of the crankshaft 7. The support surface portion 10 </ b> C has substantially the same width as the width in the front-rear direction of the journal portion 7 </ b> A of the crankshaft 7. On both the left and right sides of the support surface portion 10C, contact surface portions 10D that contact the bearing cap portion 10A with a bulkhead (not shown) of the cylinder block 2 are provided. A bolt mounting hole 10E for mounting the bearing cap portion 10A to the bulkhead is drilled through the contact surface portion 10D in the vertical direction. Then, as shown in FIGS. 4 to 6, a lightening portion 10 </ b> F is formed within the width in the front-rear direction of the support surface portion 10 </ b> C from the lower side of the bearing cap portion 10 </ b> A. The thinned portion 10F is formed up to a substantially intermediate position between the support surface portion 10C and the lower end of the bearing cap portion 10A. Specifically, as shown in FIG. 7, the thinned portion 10 </ b> F has a crank weight W positioned below when the piston 9 connected to the crankshaft 7 via the connecting rod 8 is located at the top dead center. Since it is formed above the lower end, it can be significantly reduced in weight. Since the opening portion of the thinned portion 10F is chamfered and is smoothly formed on the lower surface of the bearing beam portion 10B, a decrease in rigidity can be suppressed. Here, the thinned portion 10F is integrally formed with the bearing cap 10 by casting. Therefore, it is not necessary to chamfer the opening of the thinned portion 10F, and the thinned portion 10F is placed toward the mold. It can be easily formed simply by providing a shape corresponding to.

  The bearing beam portion 10B is formed along the lower edge of the bearing cap portion 10A, and is a plate-like body whose sectional view is curved as shown in FIG. In this bearing beam portion 10B, as shown in FIG. 4, oil dropping holes 10G, 10G,... Are drilled in the vertical direction at appropriate positions between the bearing caps 10A, 10A,. And, as shown in FIG. 9, on the lower side of the bearing beam portion 10B, on the left and right sides sandwiching the respective thinned portions 10F, 10F,... Central ribs R1 and R1 extending to 10F are formed. Connecting ribs R2, R2, and R2 for connecting the central ribs R1, R1 to the rear of the third thinned portion 10F from the thinned portion 10F at the front and rear ends and the front end of the central ribs R1, R1 are the central rib R1. And orthogonal to the axial direction of the crankshaft. A screw hole 10H for attaching a strainer (not shown) as an auxiliary machine connected to the oil pump 11 is provided at the center of the coupling rib R2 in the middle of the coupling ribs R2, R2, R2. ing. Further, an outer peripheral rib R3 is formed along both left and right ends of the bearing beam portion 10B, and the outer peripheral rib R3 and the central rib R1 are connected via a bolt mounting portion Rb. A counterbore Z is formed in the bolt mounting portion Rb, and the bolt mounting hole 10E is opened from the center of the counterbore Z.

According to the above configuration, the following effects can be obtained in the reference example.
(1) Since the thinned portion 10F is formed in each bearing cap portion 10A connected by the bearing beam portion 10B, the rigidity of the entire engine can be maintained as in the conventional case and the weight can be reduced. Further, since the thinned portion 10F is formed within the width in the front-rear direction of the support surface portion 10C of the bearing cap portion 10A, there is no need to increase the width in the front-rear direction of the bearing cap portion 10A. It can be downsized.
(2) Since the bearing beam portion 10B is a plate-like body, the bearing beam portion 10B can also serve as a baffle plate that serves as a partition plate with the oil of the oil pan 5. Therefore, it is not necessary to provide a separate baffle plate, and the cost can be reduced.
(3) Central ribs R1, R1 formed extending in the front-rear direction on both left and right sides sandwiching the respective thinned portions 10F, 10F,. Since it reinforces, the rigidity in the front-rear direction of each of the thinned portions 10F, 10F,. Further, the connecting ribs R2, R2, R2 for connecting the central ribs R1, R1 reinforce the thinned portions 10F, 10F,... In the left-right direction, so that the thinned portions 10F, 10F,. The rigidity in the left-right direction of
(4) The rigidity of the bearing cap 10 in the front-rear direction is improved by the outer peripheral ribs R3, R3 along the left and right ends of the bearing beam portion 10B. And since this outer periphery rib R3, R3 and center rib R1, R1 are connected via the bolt attachment part Rb, the rigidity of the left-right direction of the bearing cap 10 improves.
(5) Since the bolt mounting portions Rb, Rb,... Interposed between the central rib R1 and the outer peripheral rib R3 are reinforced by the central rib R1 and the outer peripheral rib R3, the rigidity of the bolt mounting portion is improved. .
(6) Since the screw hole portion 10H provided in the center portion of the connecting rib R2 is reinforced by the connecting rib R2, the rigidity of the screw hole portion 10H is improved and the mounting rigidity of the strainer as an auxiliary machine is also improved. .

[First Embodiment]
Below, 1st Embodiment in the bearing structure which concerns on this invention is described. Since this embodiment is obtained by changing a part of the bearing structure in the reference example, the same components as those in the reference example are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 10, a central rib R1 is formed on the right side of the oil drop holes 10G, 10G,... In the bearing beam portion 10B, and reinforcing ribs R4, R4,. -Is formed. The reinforcing ribs R4, R4,... Are connected at their front and rear ends to bolt mounting portions Rb, Rb. The reinforcing rib R4 corresponds to a “rib” in the claims.

  Further, as shown in FIG. 11, in the bearing cap portions 10 </ b> A and 10 </ b> A located at the front and rear ends, the same lightening portions 10 </ b> F and 10 </ b> F as those in the reference example are formed. The remaining bearing cap portions 10A, 10A, 10A located between the bearing cap portions 10A, 10A at the front and rear ends are formed with lightening portions 10J, 10J, 10J larger than the lightening portion 10F. Each of these thinned portions 10J is formed up to the vicinity of the support surface portion 10C of each bearing cap portion 10A.

According to the above configuration, the following effects can be obtained in the first embodiment.
(7) Since the central rib R1 and the reinforcing rib R4 formed in the vicinity of the left and right sides of the oil drop hole 10G reinforce the portion where the oil drop hole 10G is formed, the front and rear direction of the portion where the oil drop hole 10G is formed Stiffness is improved. Further, since the bolt mounting portions Rb and Rb formed on both front and rear sides sandwiching the oil dropping hole 10G are connected to the central rib R1 and the reinforcing rib R4, the left and right direction of the portion where the oil dropping hole 10G is formed The rigidity is improved.
(8) Since the thinned portions 10F, 10F located at the front and rear ends are smaller than the thinned portions 10J, 10J, 10J located between them, the bearing cap 10 is greatly affected by the load from the crankshaft 7. Edge rigidity is improved.
(9) Since the lightening portions 10J, 10J, and 10J are formed up to the vicinity of the support surface portion 10C of each bearing cap portion 10A, it is possible to further reduce the weight as compared with the bearing cap 10 of the reference example. it can.

As mentioned above, this invention is implemented in various forms, without being limited to the said embodiment.
(I) In the present embodiment, the present invention is applied to a bearing cap of an in-line four-cylinder engine of an SOHC (single overhead camshaft) type, but the present invention is not limited to this. For example, the present invention may be applied to a bearing cap of a DOHC (double overhead camshaft) type V-type 6-cylinder engine.
(II) In the present embodiment, the structure is such that a plurality of bearing cap portions are connected by the bearing beam portion of the plate-like body, but the present invention is not limited to this, for example, disposed at the left and right ends below the bearing cap portion. A structure in which a plurality of bearing cap portions are coupled with each other by two bearing beam portions. Even in this case, the lightening portion according to the present invention can be formed in each bearing cap portion.
(III) In the present embodiment, the thinned portion is formed integrally with the bearing cap by casting. However, the present invention is not limited to this, for example, the bearing cap portion of the bearing cap manufactured by casting. The thinned portion may be formed by grinding the lower side. Moreover, it cannot be overemphasized that the shape and magnitude | size of a lightening part can be changed suitably.
(IV) In the present embodiment, the connecting rib is configured to be orthogonal to the central rib. However, the present invention is not limited to this, and for example, a structure in which the connecting rib intersects with the central rib obliquely may be used.
(V) In this embodiment, the central rib extends from the front end to the rear end of the bearing cap. However, the present invention is not limited to this, and the central rib extends from the front end thinning portion to the rear end thinning portion. Any structure may be used as long as it extends. For example, in a structure in which the thinned portion is not formed in the bearing cap portion located at the front and rear ends, the front end of the thinned portion formed in the bearing cap portion where the central rib is located between the front and rear end bearing cap portions. The structure may be formed so as to extend from the punched portion to the meat cutout portion at the rear end.

It is a perspective view showing an engine to which a bearing cap according to a reference example is applied. It is a disassembled perspective view of the engine shown in FIG. It is a perspective view which shows the upper side of the bearing cap which concerns on a reference example. FIG. 4 is a top view of the bearing cap shown in FIG. 3. It is sectional drawing along the arrow AA of FIG. FIG. 4 is a bottom view of the bearing cap shown in FIG. 3. FIG. 6 is a cross-sectional view of a main part showing a relationship between a lightening portion of the bearing cap shown in FIG. 5 and a crank weight of a crankshaft. It is sectional drawing along the arrow BB line of FIG. It is a perspective view which shows the lower side of the bearing cap shown in FIG. It is a bottom view which shows the bearing cap which concerns on 1st Embodiment. It is sectional drawing along the arrow CC line of FIG.

Explanation of symbols

2 Cylinder block 7 Crankshaft 7A Journal part 10 Bearing cap 10A Bearing cap part 10B Bearing beam part 10C Support surface part 10F, 10J Filling part 10G Oil drain hole R1 Central rib R2 Connection rib R3 Outer peripheral rib R4 Reinforcement rib (rib)

Claims (2)

A plurality of bearing cap portions fixed to the lower side of the cylinder block and having a support surface portion that rotatably supports the journal portion of the crankshaft;
A bearing cap structure comprising a bearing beam portion for connecting these bearing cap portions to each other in the axial direction of the crankshaft,
Bolt mounting holes for mounting the bearing cap portion to the cylinder block are drilled through both sides of the support surface portion of the bearing cap portion,
From the lower side of the bearing cap portion, a lightening portion is formed within the axial width of the crankshaft of the support surface portion,
A pair of outer peripheral ribs that extend in the axial direction of the crankshaft on both sides of the lightening portion and outside the bolt mounting hole and connect the bearing cap portions are formed.
Straight ribs extending along the outer peripheral ribs and connecting the bearing cap portions are formed inside the outer peripheral ribs and outside the bolt mounting holes .
The outer peripheral rib is directly connected to a bolt mounting portion of the bolt mounting hole provided at an end portion of the bearing cap portion in the axial center of the crankshaft among the plurality of bearing cap portions,
A bearing cap portion between the linear rib and the outer peripheral rib and adjacent to one side of the bearing cap portion at the side of the bolt mounting hole and at the center in the axial direction of the crankshaft among the plurality of bearing cap portions. A pair of ribs are provided at the end,
The plurality of bearing cap portions are arranged such that the bearing cap portion adjacent to one side of the bearing cap portion in the axial central portion of the crankshaft is closer to the crankshaft shaft than the bearing cap portion in the axial central portion of the crankshaft. A bearing cap structure characterized by being formed wide in a direction orthogonal to the direction . The bearing cap structure according to claim 1, wherein the pair of ribs are provided in a C shape so as to be separated from each other toward the outer peripheral rib side from the linear rib side.

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