JPH0625625Y2 - Engine breather device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an engine breather device provided for discharging blow-by gas.

(Prior Art) Since blow-by gas of a four-cycle engine raises the internal pressure of the crank chamber and causes various obstacles, it is common to provide a breather device and discharge it to the outside. In this case, a breather chamber for separating oil is provided so as not to discharge the oil fine particles filled in the crank chamber. One of the methods is to introduce blow-by gas into the space between the cylinder head and the head cover and discharge it through a breather chamber provided inside the head cover. The oil content mixed in the blow-by gas sinks in the process of rising from the crank chamber to the breather chamber, so that the structure of the breather chamber can be made relatively simple.

However, the double overhead cam type engine
A vertically elongated breather chamber is structurally arranged above the cam shaft in the axial direction, and the breather chamber inlet is opened at its end in order to effectively use the volume of the breather chamber. Therefore, the breather chamber inlet and the camshaft end face each other at a relatively short distance. At the end of the camshaft, there is a distributor drive unit that is connected in series, and the shaft is installed so that the upper part is exposed, and the oil for lubrication is supplied abundantly.Therefore, the oil spattered by the rotation directly jumps into the breather chamber inlet. There is. In addition, since the blow-by gas passage that penetrates the cylinder block and the cylinder head opens in this portion so as to face the breather chamber inlet, the oil that has entered this passage is ejected together with the blow-by gas and enters the breather chamber inlet. It happens.

Therefore, it is necessary to provide a device for separating oil in the breather chamber, or to take measures such as increasing the blow-by gas passage diameter of the cylinder block and the cylinder head to reduce the gas flow rate, resulting in an increase in cost and an increase in engine cost. There is a problem that it hinders weight reduction and size reduction.

(Problems to be solved by the invention) As described above, in the engine in which the breather chamber is arranged in the head cover above the cam shaft, the oil for the valve mechanism may enter the breather chamber due to the rotation of the cam shaft or the blow-by gas jet. In view of the problem that the structure is complicated by the improvement of the oil separation device and the blow-by gas passage, and the cost is increased, the engine is increased in size, and the weight is increased, in the present invention, oil is used to solve these problems. A breather device for an engine, which is intended to prevent entry into the breather chamber entrance.

[Constitution of device]

(Means for Solving the Problems) In view of the above object, the present invention is an engine in which a breather chamber is arranged above a valve operating camshaft on the inner surface of a head cover, in a space between the camshaft and the breather chamber inlet, A guide plate that is integrally or integrally extended from a housing cap for a camshaft bearing or a distributor fixing driven by the camshaft is interposed, and the guide plate is a blow-by gas passage opening opening at the top surface of the cylinder head and a breather chamber inlet. Take the configuration provided in the space between and.

(Operation) In this way, the guide plate serves as a wall that hides the breather chamber inlet from the camshaft, and effectively prevents the oil scattered by the rotation of the camshaft and the oil ejected together with the blow-by gas from splashing into the breather chamber inlet. Therefore, the breather chamber does not require a special device for oil separation, and has a chamber structure of a mere expansion chamber.
The structure is simplified. Further, the blow-by gas passage, which is arranged from the crank chamber to penetrate the cylinder block and the cylinder head, can be set to be sufficiently thin without taking into consideration the fact that the flow velocity increases and jets out.
Along with downsizing, cost reduction is possible.

Since the guide plate is configured so as to be integrally or integrally extended from the housing cap for the camshaft bearing or for fixing the distributor, it can be interposed at a predetermined position together with the housing cap assembly, and it is a dedicated support device. It is possible to minimize the disadvantages in terms of cost and productivity because there is no need to provide.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 2 and 3, the cylinder block 1 has a crank chamber 2 continuously provided below, and a cylinder head 3 superposed above it. 4 is a piston, 5 is a crankshaft, and 6 is a connecting rod.

An intake valve 8 and an exhaust valve 9 for opening and closing the combustion chamber 7 are arranged in the cylinder head 3 and controlled by an intake cam 10 and an exhaust cam 11.
The intake camshaft 12 and the exhaust camshaft 13 are pivotally supported by a lower half bearing hole 14 formed in the upper surface of the cylinder head 3 and a housing cap 15 having an upper half bearing hole. A driven pulley 16 is fixed to one end of each of the cam shafts 12 and 13, and
The rotation is transmitted by the timing belt from the drive pulley 17 fixed to.

A head cover 18 is attached to the upper surface of the cylinder head 3, and the valve mechanism including the camshafts 12 and 13 is placed in a hermetically sealed state. This valve mechanism chamber 19 is isolated from the timing belt chamber, and oil is enclosed therein.

An input shaft 22 of a distributor 21 is connected to an opposite end of the exhaust camshaft 13 via a joint 20. This distributor 21
Are fixed by the upper surface of the cylinder head 3 and the housing cap 23.

Further, a vertically long breather chamber 24 is formed inside the head cover 18 along the upper side of the exhaust camshaft 13. A breather chamber inlet 25 is opened on the lower surface of the distributor 21 side end of the breather chamber 24, and a breather hole 26 is opened to the outside at the chamber end on the opposite side. The breather hole 26 is connected to the clean side of the air cleaner or the like.

On the other hand, the blow-by gas passage 27, which is guided upward from the crank chamber 2 through the cylinder block 1 and the cylinder head 3, faces the breather chamber inlet 25 and faces the upper surface of the cylinder head 3, as shown in FIG. It opens and communicates with the valve mechanism chamber 19. An oil passage 28 for supplying oil to the valve operating mechanism also opens on the upper surface of the cylinder head 3 so as to intersect the blow-by gas passage 27.

Then, between the breather chamber inlet 25 and the opposing ends of the exhaust cam shaft 13 and the distributor input shaft 22 that face each other with the joint 20 in between, and between the breather chamber inlet 25 and the blow-by gas passage 27 opening. The guide plate 29 is placed so as to block the upper and lower sides. The guide plate 29 corresponds to the housing cap 2
3 extends in the axial direction from the inner side surface of the housing 3, and is set to be held at the above position when the housing cap 23 is assembled. The guide plate 29 and the housing cap 23 may be integrated or may be combined separately.

In this way, the oil scattered by the rotation of the exhaust cam shaft 13 and the distributor input shaft 22 hits the guide plate 29 and falls down to the breather chamber inlet 2
No invasion of 5. Further, when the blow-by gas is ejected from the blow-by gas passage 27 and introduced into the breather chamber inlet 25, even if the oil that enters the blow-by gas passage 27 or oil around the opening is ejected together with the blow-by gas, The guide plate 29 receives the oil and drops it, and introduces only the blow-by gas that bypasses the guide plate 29 into the breather chamber 24.

[Effect of device]

As described above, in the engine breather device according to the present invention, the guide plate extending from the housing cap is interposed in the space between the camshaft and the breather chamber inlet, while the guide plate is opened on the upper surface of the cylinder head. Since it is provided in the space between the opening of the blow-by gas passage and the inlet of the breather chamber, it effectively prevents the oil due to the rotation of the camshaft and the jet of blow-by gas from entering the inlet of the breather chamber, and the blow-by gas passage and the oil passage. ,
This has the effect of expanding the degree of freedom in designing the shape of the breather chamber and its inlet, simplifying the structure of the breather chamber, reducing the weight of the engine, making it compact, and reducing costs.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of an engine cylinder head showing an embodiment of the present invention, and FIG. 2 is an AA of FIG. 3 of the engine.
FIG. 3 is a vertical sectional side view of the engine as viewed in the direction of the arrow. 1 ... Cylinder block, 2 ... Crank chamber, 3 ... Cylinder head, 12 ... Intake camshaft, 13
...... Exhaust camshaft, 15 ...... (camshaft bearing) housing cap, 18 ...... head cover, 20 ...... joint, 21 ...... distributor, 22 …… input shaft, 23 …… (distributor fixing) housing cap, 24 …… Breather room, 25
…… Breazer room entrance, 27 …… Blow-by gas passage, 2
8 ... Oil passage, 29 ... Guide plate.

Claims (1)

[Scope of utility model registration request] 1. An engine having a breather chamber disposed above a valve operating camshaft on the inner surface of a head cover, for fixing a camshaft bearing or a distributor driven by the camshaft in a space between the camshaft and the breather chamber inlet. An engine characterized in that a guide plate integrally or integrally extending from a housing cap is interposed, and the guide plate is provided in a space between a blow-by gas passage opening opening on the upper surface of the cylinder head and a breather chamber inlet. Breather device.