JPH017847Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a main bearing structure for a crankshaft of an automobile engine.

Generally, the crankshaft of an automobile engine receives the pressure exerted by the piston through a connecting rod and converts the reciprocating motion of the piston into rotational motion, thereby converting the pressure acting on the piston into engine torque.

As a main bearing structure of such a crankshaft, there is a conventional structure shown in FIGS. 1 and 2, for example. In Figs. 1 and 2, 1 indicates a cylinder block, and this cylinder block 1 is connected to cylinder 2.
This type is integrally formed with the housing part 3. 4 is a bearing part of the cylinder block 1, and this bearing part 4 is connected to the housing part 3 by a bulkhead 5 which is a partition wall of the cylinder block 1.
is connected to. A bearing cap 6 cooperates with the bearing portion 4 to rotatably support the crankshaft 4, and the bearing cap 6 is fastened to the bearing portion 4 with a pair of bolts 8. Note that the lower end portion of the housing portion 3 of the cylinder block 1 is generally referred to as a skirt portion 9.

However, in such a conventional crankshaft main bearing structure, the bulkhead 5 that connects the bearing part 4 and the housing part 3 is
As shown in FIG. 1, since it was formed with a substantially uniform thickness, the following problems arose. That is, when a fluctuating load due to combustion impact force or the like acts on the crankshaft 7, the bearing portion 4 vibrates violently in the direction of the rotational axis of the crankshaft 7, as the deformed state is shown by the broken line in FIG. As a result, the skirt portion 9 vibrates in the opening/closing direction as shown by the broken line in FIG. 2, and as a result, large noise is generated from the cylinder block 1 and the covers attached thereto. There was a problem.

This idea was developed by focusing on these problems.In the main bearing structure of a crankshaft, which includes a bulkhead and a bearing cap, branch parts are provided at both ends of the bearing part in the longitudinal direction, and one end of the bulkhead is provided with branch parts. is connected to the branched portion, and the other end is bifurcated from the one end and integrally connected to the housing, and a bearing cap is arranged on the bulkhead substantially parallel to the rotational axis of the crankshaft. The object of the present invention is to solve the above-mentioned problems by fixing the bulk head to the bulk head using a plurality of fastening members.

This invention will be explained below based on the drawings.

3 to 5 are diagrams showing an embodiment of this invention. First, the configuration will be explained. Note that the same parts as in the prior art are given the same reference numerals. 3 to 5, reference numeral 1 indicates a cylinder block, and this cylinder block 1 is of a type in which a cylinder 2 is integrally formed with a housing portion 3. 4 is a bearing part of the cylinder block 1, and this bearing part 4
Branches are provided at both longitudinal ends of the
Bulkhead 5 which is the partition wall of cylinder block 1
It is connected to the housing part 3 by. One end 5a of the bulkhead 5 is integrally connected to the branch part of the bearing part 4, and the other end 5b is connected to the one end 5a.
It is branched into two forked shapes and is integrally connected to the housing part 3. That is, bulkhead 5
has a pair of leg parts 5c and 5d that diverge from the bearing part 4 toward the housing part 3 in a shape that widens toward the end, and a cross-section is formed between these leg parts 5c and 5d in order to reduce the overall weight of the bulkhead 5. A gap 10 having a substantially triangular shape is formed. Further, 6 cooperates with the bearing part 4 to form the crankshaft 7,
That is, it is a bearing cap that rotatably supports the crank journal, and as shown in detail in FIG. 4, the bearing cap 6 has both longitudinal ends 6a and 6b formed in a shape that widens toward the end. A pair of bolt holes 11 and 12 are formed in both ends 6a and 6b, respectively, and the bearing cap 6 is connected to the bulk head 5 by a plurality of bolts 8 through these bolt holes 11 and 12.
It has been concluded. That is, the bearing cap 6 is fastened by a plurality of fastening members, such as bolts 8, arranged substantially parallel to the rotational axis of the crankshaft 7 at both longitudinal ends 6a and 6b.
It is fixed to the bulkhead 5. Note that 9 is a skirt portion which is the lower end of the housing portion 3 of the cylinder block 1, and 13 is a water jacket.

As described above, in the crankshaft main bearing structure according to this invention, the crankshaft 7
Even if a fluctuating load due to combustion impact force etc. acts on the bulkhead 5, the cross section of the bulkhead 5 is formed into a substantially triangular shape, and the bearing cap 6 is firmly attached to the bulkhead 5 in a direction substantially parallel to the axis of rotation of the crankshaft 7. Therefore, vibration of the bearing portion 4 and the bearing cap 6 in the direction of the rotational axis of the crankshaft 7 is significantly reduced. That is, in this crankshaft main bearing structure, the supporting rigidity of the crankshaft 7 in the rotational axis direction is significantly increased. In addition, bulkhead 5
Since the void 10 is formed in the space 10, the weight does not increase.

Although a four-cylinder crankshaft has been described in this embodiment, the main bearing structure of the crankshaft according to this invention can be adopted for other types of crankshafts as well.

As explained above, according to this idea,
In the main bearing structure of a crankshaft equipped with a bulkhead and a bearing cap, a branch part is provided at both longitudinal ends of the bearing part, one end of the bulkhead is connected to the branch part, and the other end is connected to the branch part from the one end. The bearing cap is branched into a forked shape and integrally connected to the housing, and the bearing cap is fixed to the bulkhead by a plurality of fastening members arranged approximately parallel to the axis of rotation of the crankshaft. It is possible to significantly reduce the vibration in the direction of the rotational axis of the crankshaft, and therefore also suppress the opening/closing vibration of the skirt part, and as a result, the noise caused by these vibrations from the cylinder block etc. can be significantly reduced. can get. Further, bending and swinging of the crankshaft can also be suppressed.

[Brief explanation of drawings]

Fig. 1 is a schematic bottom view showing the main bearing structure of a conventional crankshaft, Fig. 2 is a schematic sectional view taken along the - arrow in Fig. 1, and Fig. 3 is an implementation of the main bearing structure of the crankshaft according to this invention. FIG. 4 is a perspective view of the bearing cap, and FIG. 5 is a schematic sectional view taken along the - arrow in FIG. 3. 1...Cylinder block, 3...Housing part, 4
... Bearing part, 5... Bulkhead, 5a... One end of bulkhead, 5b... Other end of bulkhead, 6... Bearing cap, 6a, 6b... Both longitudinal ends of bearing cap, 7... Crankshaft, 8... Bolt (fastening) Element).

Claims (1)

[Scope of utility model registration request] A main bearing structure for a crankshaft includes a bulkhead that connects a housing part and a bearing part of a cylinder block, and a bearing cap that is fixed to the bulkhead and cooperates with the bearing part to rotatably support the crankshaft. A branch part is provided at both longitudinal ends of the bearing part, one end of the bulkhead is connected to the branch part, and the other end is bifurcated from the one end and integrally connected to the housing, A main bearing structure for a crankshaft, characterized in that a bearing cap is fixed to the bulkhead by a plurality of fastening members arranged substantially parallel to the rotational axis of the crankshaft.