JPS5891310A - Camshaft bearing structure in parallel multi-cylinder engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camshaft bearing in an engine, and more particularly to a camshaft bearing in an engine having a plurality of pulps in at least one passage on the intake side or exhaust side of a cylinder. It is.

Figure 1 (The figure shows the upper part of the cylinder head of the engine in which acid has been precipitated, and Figure 1 (b) shows its vertical cross section.This engine has two or more cylinders in one cylinder, for example, two cylinder heads. This is a 1 cylinder 4 nozzle engine with an intake pulp 1.1 and two exhaust valves 2,2. It is actuated by cams 5, 5 of 4.4 (in which only one camshaft is shown).

In the engine shown in Fig. 1 (a) and (b),
Two valves 1, 1 and 2.2 are each set as one set, and these are simultaneously operated by one cam 5.5 through a bifurcated rocker arm 6. In this engine, the bearing 7 is disposed between the cams 5 to support the camshaft 4, and in order to make the cylinder head 3 compact,
No bearing is provided at the end IK of the camshaft 4.

Therefore, as shown in FIG. 2, in such a bearing structure, each of the five cams located at the end of the camshaft 4 is cantilevered.
Moreover, since the distance from the bearing 7 to the cam 5 becomes long, the camshaft 4 tends to bend.

Furthermore, the gap 8 between the bearing 7 and the shaft 4 increases in accordance with the distance 11L at the position of the ram 5, which has an inconvenience that affects the operation of the pulp.

In addition, the camshaft 1 of the engine shown in Fig. 3 (4, (b))
No. 4 has its base supported by a bearing 17, and therefore does not have the above drawback, but has another drawback in that the length t of the cylinder head 13 becomes large, as shown in FIG. There is. In addition, in FIGS. 3A and 3B and FIG. 4, 11 is an intake pulp, 12 is an exhaust valve, 15 is a cam, and 16 is a rocker arm.

The present invention provides a camshaft bearing structure that eliminates these drawbacks, and is characterized by the fact that at least one of the intake side and the exhaust side of one cylinder is provided with multiple I&- pulp. In the engine, each cam corresponds to the above plurality of pulps.

The present invention also provides a bearing for a camshaft in an engine in which the bearing is disposed on the camshaft between the cams.

An embodiment of the present invention will be described below in detail with reference to the attached drawings WJK.

Figure 5 (a) is a plan view showing the bearing 27 with the upper part of the cylinder head 23 of the engine cut out and the camshaft removed according to the present invention 11, and Figure 5 (b) is a plan view showing the bearing 27 according to the present invention. FIG. s2 in the engine of this embodiment excluding the bearing 27 and camshaft 24 is no different from the engine shown in i@1 (a), (b) and FIG. 3 (b).This embodiment In this case, a total of four pulps are arranged, two each for intake and exhaust pulps per cylinder.For example, two pulps 21 and 22 in the intake example are moved by the cams 25 and 25 of one camshaft 24. activated and the other two pulps on the exhaust side (not shown)
is actuated by the other cam (not shown). The two illustrated intake valves 21.22 each bear via a rocker arm 26.26 on a respective cam 25.25 arranged on the camshaft 24, and the camshaft between these cams 25.25 Part 248 K is auxiliary bearing 27'
is provided, and supports the end of the camshaft 24 by the bearing. This auxiliary bearing 27' is a half bearing like the other bearings 27, and its upper part 27'a is connected to the upper part 271 of the bearing 27 by a lip 28, and its lower part 27'b is shown in FIG. (As shown in Figures K and M6, there is a length of 14 turns of the camshaft 24! 4 degrees.
* is formed to provide a relief when drilling guide holes for the pulp 21. In addition, in Fig. 5 (11, 29
30 is a return spring for the pulp 21, 22, 31 is a piston, and 32, 33 is an intake passage. Note that the exhaust passage is not shown.

The lower bearing 2Th of the camshaft 27 and the lower bearing 27b' of the auxiliary bearing 27'
7b, 27b' are integrally formed with a stop bearing 27m
and 27a' are placed and fixed by tightening bolts 35 and 35, respectively. In this way, the camshaft 24 is supported by the bearing 2 and the auxiliary bearing 27'.

The auxiliary bearing 27' is the cam 25°1 at the end of the camshaft 24.As explained above, according to the present invention, the camshaft bearing structure is such that the end of the camshaft is supported by the auxiliary bearing, and the bearing The pulp located on the outermost side is also on the inside,
In addition, the distance between the cam and the auxiliary bearing that supports cough pulp is extremely short, so there is no risk of the camshaft bending, so the shaft diameter can be reduced, and the durability of the bearing is also improved. The influence of the pulp operation due to the gap between the cylinder and the shaft is also eliminated, and the length of the cylinder head can be shortened, thereby reducing the weight.

[Brief explanation of the drawing]

Fig. 1(a) is a 1m cross-sectional plan view showing a conventional camshaft bearing in a multi-valve engine;
Fig. 2 is a longitudinal cross-sectional view of Fig. 1 (a), Fig. 3 (a) is a diagram conceptually showing the bearing structure of Fig. 1 (a), Fig. 3 (a) is a longitudinal cross-sectional view of Fig. The partially sectional plan view shown (3rd issue) is a vertical cross-sectional view of Fig. 3 (a), and Fig. 4 is a diagram conceptually showing the bearing structure of Fig. 3 (→, 伽).
Figure (a) is a partially sectional plan view showing a camshaft bearing according to the present invention, Figure 5 is a vertical cross-sectional view of Figure 5 (a), and Figure 6 is an auxiliary bearing viewed from the axial direction. It is a sectional view of the main parts of the machine/gin. 21... Intake valve, 22... Exhaust pulp, 23.
... / cylinder head, 24 ... camshaft, 24a ...
Camshaft portion, 25...Cam, 26...Rocker arm% 27...Bearing, 27a...Upper part, 27b...
Lower part, 27'...Auxiliary bearing. 27'a...Top, 27'b-...Bottom, 2g...
・Rip, 29.30...Return spring, 31...Piston, 32...Intake passage, 33...-Exhaust passage. Applicant Honda Motor Co., Ltd. Agent Patent Attorney Toshihiko Watanabe No. 15! IJ (0) pPJ1 diagram (b) Brother 2 diagram 3 diagram (0) (b) Crow 5N! 1 ] [ (b) Pun 6 Figure 3

Claims (1)

[Claims] l. In a camshaft bearing in an engine in which a camshaft for opening and closing the pulp is disposed above the cylinder and a plurality of valves are provided on at least one of the intake or exhaust side of one cylinder, each of the plurality of valves is A camshaft bearing in an engine characterized by having separate cams associated with each cam and a bearing disposed on the camshaft between the cams.