JP3222354B2 - Bearing device for camshaft in internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called DOHC type internal combustion engine having a camshaft for an intake valve and a camshaft for an exhaust valve on the upper surface of a cylinder head. The present invention relates to a bearing device for supporting a shaft and a cam shaft for an exhaust valve with respect to a cylinder head.

[0002]

2. Description of the Related Art In general, in a DOHC type internal combustion engine of this type, rotation of a crankshaft is applied to one of two camshafts disposed on the upper surface of a cylinder head via a timing chain or a belt. The rotation of one camshaft is transmitted to the other camshaft via a gear fitted on the two camshafts so as to mesh with each other.

In this case, both camshafts are supported by a bearing part integrally provided on the upper surface of the cylinder head and a bearing cap body fastened to the bearing part by a pair of left and right bolts. Be composed. JP-A-59-25006 and JP-A-3-3340 as prior art
Japanese Patent Application Publication No. 8-28139 discloses a bearing device in which a bearing cap for one camshaft and a bearing cap for the other camshaft are integrated into one common bearing cap, and the common bearing cap is mounted on a cylinder head. It is proposed to fasten to the bearing part with four bolts, two bolts arranged on both sides of one camshaft and two bolts arranged on both sides of the other camshaft. ing.

[0004]

However, in this prior art, a part for integrating a bearing cap for one camshaft and a bearing cap for the other camshaft into one common bearing cap is provided. On the other hand, when this common bearing cap is attached to a bearing portion on the cylinder head side, two bolts provided on both sides of one cam shaft and the other cam are used. By using two bolts arranged on both sides of the shaft for fastening with four bolts, the number of bolts is large, and therefore, the man-hour for drilling the bolt holes and the bolt fastening As the number of operations increases, not only does the cost considerably increase, but also the portion of the common bearing cap body between the two camshafts is fastened with two bolts. Conclusion of there has been a problem that tends to be excessive.

According to the present invention, in a DOHC type internal combustion engine, rotation of a crankshaft is transmitted to one of two camshafts, and rotation is transmitted from one camshaft to the other camshaft. It is an object of the present invention to pay attention to the configuration, and to solve the above-mentioned problem by using this fact.

[0006]

SUMMARY OF THE INVENTION In order to achieve this technical object, the present invention relates to a method of manufacturing a vehicle, comprising the steps of: providing a crankshaft on one of an intake valve camshaft and an exhaust valve camshaft disposed on an upper surface of a cylinder head; While transmitting the rotation of the shaft, and configured to transmit the rotation from one cam shaft to the other cam shaft, the two cam shafts, bearing portion provided on the cylinder head side,
This bearing portion is supported by a bearing cap body fastened by a plurality of bolts, and the bearing cap body for the one cam shaft and the bearing cap body for the other cam shaft are combined into one common bearing cap body. In a camshaft bearing device for an integrated internal combustion engine, the common bearing cap body is fastened to a bearing portion by three bolts, a first bolt, a second bolt, and a third bolt . The first bolt among the bolts is
Close to the outside of one camshaft to which the rotation of the shaft is transmitted.
Place the second bolt close to the outside of the other camshaft
While each arranged in the site, the rest of the third bolt, before
Position closer to one camshaft than the middle of both camshafts
And between the one camshaft and the third bolt.
Distance equal to the distance from one camshaft to the first bolt
It is arranged in the part which did . ".

[0007]

[Operation] In this configuration, the rotation of the crankshaft is
After being transmitted to one of the camshafts first, by being transmitted from the one camshaft to the other camshaft, the bearing load on one of the two camshafts is reduced by the bearing load on the other camshaft. Becomes larger than the load.

Therefore, in the case where the common bearing cap body for the two camshafts is fastened to the bearing portion with bolts, the present invention is configured as described in the claims, so that the bearing load of the common bearing cap body is obtained. Can be firmly fastened with two bolts adjacent to both sides of the one camshaft with the one camshaft interposed therebetween. It can be fastened to the side bearing portion with three bolts in a state where both of the camshafts can be reliably supported.

[0009]

Thus, according to the present invention, three bolts for fastening to the common bearing cap body are reduced by one less than the four prior arts in a state where both camshafts can be reliably supported. It is possible to reduce the number of man-hours for drilling a bolt hole and the number of bolt fastening steps,
Since an increase in cost can be prevented, and a portion between the two camshafts of the common bearing cap body is fastened by one third bolt, it is possible to reliably avoid excessive fastening of this portion. Having.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In this figure, reference numeral 1 denotes a cylinder block, and reference numeral 2 denotes a cylinder head fastened to the upper surface of the cylinder block 1 by a plurality of head bolts (not shown).

Reference numeral 5 denotes a cam shaft for the intake valve 6, and reference numeral 7 denotes a cam shaft for the exhaust valve 8. Both cam shafts 5 and 7 are provided in the valve mechanism chamber 2a on the upper surface of the cylinder head 2. And is supported in parallel by the intermediate bearing devices 4a and 4b at a portion between the cylinders and the bearing device 3 at one end. The two camshafts 5 and 7 are configured to rotate in conjunction with each other by gears 8 and 9 disposed inside the bearing device 3 so as to mesh with each other. A timing pulley 10 is fitted to a shaft end of one of the shafts 5 and 7 protruding outward from the bearing device 3, and a timing belt from a crankshaft (not shown) is attached to the timing pulley 10. 11 is wound so that the rotation of the crankshaft is transmitted to one camshaft 7, and the rotation is transmitted from the one camshaft 7 to the other camshaft 5.

The bearing device 3 includes a bearing portion 12 integrally formed with the cylinder head 2 and a common bearing cap 13 disposed on the upper surface thereof. A first bolt 14 and a second bolt 14 are attached to the bearing 12 on the cylinder head 2 side.
When fastening with three bolts consisting of 15 and third bolts 16 , the three bolts 14, 15, 16 are used.
The first bolt 14 is connected to the clamp of the camshafts 5 and 7.
Close to the outside of the exhaust valve camshaft 7 to which the rotation of the shaft is transmitted.
The second bolt 15 is connected to the cam shaft with respect to the intake valve.
While each disposed in a portion close to the outer 5, the remaining second
The 3 bolts 16 are exhausted more than the middle between the camshafts 5 and 7.
A position close to the valve cam shaft 7 and the exhaust valve
The distance L2 from the shaft 7 to the third bolt 16 is determined by an exhaust valve.
Equal to the distance L1 from the cam shaft 7 for use to the first bolt 14
It is arranged in the site where it was done .

In this configuration, the rotation of the crankshaft is
First, the power is transmitted to one camshaft 7 via the timing belt 11 and then transmitted from the one camshaft 7 to the other camshaft 5 via gears 8 and 9 meshing with each other. The bearing load on one cam shaft 7 of the bearing devices 3 of the two cam shafts 5 and 7 is larger than the bearing load on the other cam shaft 5.

Therefore, when the common bearing cap body 13 for the two camshafts 5 and 7 is fastened to the bearing part 12 by bolts, the above-described structure allows the common bearing cap body 13 The one camshaft 7 having a large bearing load is connected to two bolts 14 and 16 that are located on both sides of the one camshaft 7 with the one camshaft 7 interposed therebetween.
Therefore, both the camshafts 5 and 7 can be securely fixed to the bearing portion 12 on the cylinder head side by the three bolts 14, 15 and 16. It can be fastened under the condition that the bearing can be used.

The three bolts 14, 15, 16
Among the first and second bolts 14 and 15 at both ends, knock bushes 17 and 18 for positioning the common bearing cap body 13 with respect to the bearing part 12 on the cylinder head side are provided with the common bearing cap body 13 and the bearing. Part 1
2 is fitted so as to fit both. Also, for power transmission from the crankshaft to one exhaust valve camshaft 7,
Needless to say, a timing chain may be used in place of using the timing belt 11 of the above embodiment.

[Brief description of the drawings]

FIG. 1 is a plan view of a cylinder head showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an enlarged sectional view taken along line IV-IV of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 3 Bearing device 5 Camshaft for intake valve 7 Camshaft for exhaust valve 8, 9 Gear 10 Timing pulley 11 Timing belt 12 Bearing part 13 Common bearing cap body 14, 15, 16 Bolt 17, 18 Knock ring

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01L 1/04 F01L 1/02 F02F 1/24

Claims (1)

(57) [Claims] A camshaft rotation is transmitted to one of an intake valve camshaft and an exhaust valve camshaft disposed on an upper surface of a cylinder head, and the camshaft is rotated from one camshaft to the other camshaft. On the other hand, the two camshafts are supported by a bearing portion provided on the cylinder head side and a bearing cap body fastened to the bearing portion with a plurality of bolts. In a camshaft bearing device for an internal combustion engine in which the bearing cap body for one camshaft and the bearing cap body for the other camshaft are integrated into one common bearing cap body, the common bearing cap body is used as a bearing part. The first bolt, the second bolt, and the third bolt are fastened to the three bolts, and the first bolt among the three bolts is replaced with the aforementioned bolt.
Close to the outside of one cam shaft to which the rotation of the rank shaft is transmitted
A second bolt is attached to the outside of the other cam shaft
The remaining third bolts are arranged at the adjacent parts, respectively.
Is closer to one of the camshafts than the center between the two camshafts
Position and from the one camshaft to the third bolt.
Is the distance from one camshaft to the first bolt
A bearing device for a camshaft in an internal combustion engine, wherein the bearing device is disposed at a position equivalent to: