JPH0660749U - Internal combustion engine - Google Patents

Abstract

(57) [Summary] [Aim] By slightly increasing the weight, the rigidity of the entire cylinder block is improved without transmitting the vibration of the bearing cap part 1 in each direction to the side wall, and the radiated sound from this cylinder block is improved. A reduced internal combustion engine is provided. [Composition] An internal combustion engine in which a bed frame 9 is laminated on the lower surface of a ladder frame 3 provided on an opening surface of a cylinder block, and an oil pan 10 and a cylinder block are fastened together to be integrated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an internal combustion engine provided with a bed plate that reinforces a ladder frame provided in the lower part of the cylinder block in order to reduce radiation noise generated from the cylinder block of the internal combustion engine.

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, in a cylinder block 7 of an internal combustion engine as shown in FIG. 2, a vibration input from the crankshaft due to an impact force during combustion of the engine causes the bearing cap portion 1 to move in the axial direction of the crankshaft, that is, XY. There is a problem that the vibration in the front-back direction shown in Fig. 3 is likely to occur, which induces the vibration of the cylinder block skirt and is radiated as noise to the outside.The bearing is intended to reduce such noise. JP-A-58-77941 relating to beams has been proposed.

As shown in FIG. 3, this known technique is one in which each bearing cap portion 1 is integrally connected by a beam portion 2, which is generally called a bearing beam system. Vibration such as twisting is suppressed to improve the rigidity of the entire cylinder block 7. However, also in this case, the torsional vibration indicated by the arrow Z and the bending around the bore axis were not sufficiently suppressed.

Therefore, as shown in the schematic front view of FIG. 4 and the perspective view of FIG. 5 showing only the double-hatched portion of FIG. 4, both sides of each bearing cap portion 1 of FIG. Internal combustion engines provided with a ladder frame 3 have been put into practical use. The cylinder block 7 having the ladder frame 3 in the lower opening has a feature that the rigidity of the lower part of the block is high and vibration of the skirt portion does not easily occur. However, the vibrations of the left and right side walls of the cylinder block and the bearing in the front-rear direction are transmitted to the side wall 8 of the ladder frame 3, and the vibration of the side wall 8 becomes large. Moreover, the vibration in the bending direction cannot be suppressed and a wavy vibration is generated. There is a problem that it occurs.

As a countermeasure against the above-mentioned drawbacks of the cylinder block, a thick wall portion 5 as shown in FIG. 6 is provided on the lower edge of the side wall portion connected to the cylinder block skirt portion, and Japanese Utility Model Laid-Open No. 59-552 proposes a structure of a crank room of an automobile engine in which a triangular reinforcing portion 6 that obliquely connects the bearing cap portion 1 and the bearing cap portion 1 is integrally formed. There is. In this invention, the rigidity of the lower portion of the cylinder block is improved by the triangular reinforcing portion 6, but there is a problem that the structure of the block portion becomes complicated and the weight increases.

[0006]

[Problems to be solved by the device]

 The present invention has been made in order to solve the above-mentioned problems of the prior art. Due to a slight increase in weight, the vibration of the bearing cap in each direction is not transmitted to the side wall, and the rigidity of the entire block is improved. It is an object of the present invention to provide an internal combustion engine that can reduce the noise emitted from the cylinder block as a result.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, an internal combustion engine of the present invention is equipped with a bed plate locally provided with an opening through which a moving part of a crank can pass, on a lower surface of a ladder frame provided at a lower part of a cylinder block. The cylinder block is integrally fixed with at least a peripheral bolt such as an oil pan bolt.

The bed plate that is laminated on the lower surface of the ladder frame to reinforce it is a flat plate, and the opening through which the moving part of the crank passes is formed to a minimum in order to minimize the opening. ing. This opening has an elliptical shape with as few corners as possible, and is designed so as not to reduce the strength of the plate.

[0009]

[Work]

 Since the bed plates with few openings are stacked so as to cover the openings on the lower surface of the ladder frame, the vibration of the bearings supported by the ladder frame is not transmitted to the side wall of this ladder frame, and The lower opening is strengthened, and as a result, the cylinder block block vibration is not transmitted to the side wall.

[0010]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a state of a ladder frame before being attached to a cylinder block according to an embodiment of the present invention. The cylinder block of this embodiment is similar to the conventional example of FIG. 5, in which both sides of each bearing cap portion 1 are connected together by side walls 8 to be integrated, and a ladder frame 3 having an opening at the lower portion of the block is not shown in the drawings. It is designed to support the lower part of the.

Next, the bed plate 9 adopted in the present invention is mounted on the lower surface of the ladder frame 3, and the oil pan 10 is further mounted on the bottom surface thereof. The bed plate 9 together with the oil pan 10 is fixed to the peripheral frame holes such as the oil pan bolt hole 12 by screwing and tightening peripheral bolts such as bearing bolts and oil pan bolts which are not shown. It is fixed by co-tightening together. Therefore, the bottom plate is provided below the ladder frame 3.

The bed plate 9 is designed so as not to have a large opening so as to reduce the weight and increase the strength as much as possible, and the opening 9a is provided at a portion through which a moving portion of the crank passes. It is formed to a minimum considering the parts where oil passes. Further, the opening 9a has a circular shape or an elliptical shape with as few corners as possible as shown in the drawing, and in some cases, a rectangular shape in which corners are connected by a large arc can be adopted.

As described above, by fixing the bed plate 9 to the ladder frame 3 having the bearing cap portions 1 together, for example, the vibration of the bearing cap portion 1 in the front-back direction of the arrow XY can be suppressed, As a result, the vibration of the bearing is not transmitted to the side surface of the cylinder block. Also, by mounting and fixing the bed plate 9, the opening of the lower portion of the cylinder block is narrowed, and the rigidity of the entire block is improved.

Further, by mounting the bed plate 9 made of a low-density aluminum material or the like on the ladder frame 3, it is possible to provide a cylinder block that is lighter in weight than when the shape of the ladder frame 3 is changed.

[0015]

[Effect of device]

 As described above, the internal combustion engine of the present invention is equipped with a bed plate locally provided with an opening through which the moving part of the crank can pass, on the lower surface of the ladder frame provided at the lower part of the cylinder block. A peripheral bolt such as a pan bolt is integrally fixed to the cylinder block.

Therefore, the vibration of the bearing cap portion that supports the crankshaft in the front-rear direction is suppressed, and the vibration of the bearing is not transmitted to the side surface of the block, so that the vibration of the side wall is less likely to occur. Also, by installing the bed plate, the opening at the bottom of the cylinder block becomes narrower, which improves the rigidity of the entire block, making it difficult for torsional vibration, bulkhead vibration, and bearing vibration to occur.

As a result, the internal combustion engine of the present invention can reduce the radiation noise generated from the cylinder block. Further, in the present invention, if a lightweight ladder frame such as an aluminum material is adopted, the weight can be reduced and a sufficient rigidity can be obtained as compared with the case where the ladder frame shape is changed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state before assembly of a ladder frame, a bed plate and an oil pan, which form a lower structure of a cylinder block of an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a main part of a conventional internal combustion engine before a bearing cap is attached to a cylinder block.

FIG. 3 is a main part perspective view showing a bearing beam system of a conventional cylinder block.

FIG. 4 is a schematic front view showing a portion of a conventional cylinder block adopting a ladder frame method.

5 is a perspective view of the ladder frame of FIG. 4. FIG.

FIG. 6 is a plan view of a main part of a cylinder block skirt portion of another conventional example.

[Explanation of symbols]

1 Bearing cap 3 Ladder frame 9
Bed plate 9a Opening 10 Oil pan.

Claims (1)

[Scope of utility model registration request] 1. A bed plate, which is locally provided with an opening through which a moving portion of a crank can pass, is attached to a lower surface of a ladder frame provided at a lower portion of a cylinder block, and at least a peripheral bolt such as an oil pan bolt is used to mount the bed plate. Internal combustion engine fixed integrally with the cylinder block.