JPH0130623Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a power distribution device used in an internal combustion engine.

(Prior art) As a conventional power distribution device for internal combustion engines, there is, for example, the one shown in Fig. 1 (Japanese Patent Laid-Open No. 115865
issue).

This power distributor is attached to a cylinder block 3 of an internal combustion engine by means of a flange 2 provided on a housing 1. Inside the housing 1 is a metal bearing 5.
A shaft 7 is pivotally supported by a thrust ball bearing 6, and a gap 9 is formed around the shaft 7, which is separated from a power distribution chamber 16 by the ball bearing 6. This cavity 9 is surrounded by the housing 1, the ball bearing 6, the shaft 7, and the metal bearing 5, and communicates with the inside of the crankcase 4 through the gap between the metal bearing 5 and the shaft 7. Further, the shaft 7 is connected to a crankshaft or a camshaft of the engine via a coupling 8 at the end on the cylinder block side, and rotation is transmitted thereto. At the other end of the shaft 7, a centrifugal advance device 10, a magnetic rotor 11, a rotor 14 consisting of a rotor electrode 12, an insulator 13, etc. are sequentially mounted. Further, a cap 15 is attached to the housing 1, and a power distribution chamber 16 for accommodating the rotor 14 and the like is formed within the cap 15 and the housing 1. Furthermore, a center electrode 17 and a plurality of outer electrodes 18 are mounted on the cap 15, and a ventilation hole 19 is provided in the housing 1 to allow ozone generated by discharge between the rotor electrode 12 and the outer electrode 18 to escape to the outside during driving. ing. In addition, 20 is a negative pressure advance control plate connected to the diaphragm device 21 by a rod 22, 23 is a control circuit, and 24 is an ignition position detector. By the way, in such a power distribution device, the metal bearing 5 is lubricated by the engine oil scattered inside the engine, while the ball bearing 6 is lubricated by lubricating oil (grease) sealed inside the bearing in advance. The structure is such that it is lubricated.

However, in the case of the above conventional power distributor,
Since the power distribution room is connected to the outside through the ventilation opening, the pressure is at atmospheric pressure.However, because the above-mentioned cavity is connected to the inside of the crankcase through the gap between the shaft and the metal bearing, when the negative pressure inside the crankcase increases, the pressure inside the crankcase increases. , the pressure difference between the power distribution chamber and the cavity increases, and the lubricating oil (grease) sealed in the ball bearing flows out into the cavity. As a result, the ball bearings seize up due to the heat generated by the rotation of the shaft, causing problems such as abnormal noises and the shaft becoming stuck.

(Purpose of the invention) Therefore, the present invention eliminates the leakage of lubricating oil from the ball bearing by communicating the gap and the power distribution chamber and reducing the pressure difference between the gap and the power distribution chamber, thereby preventing seizure of the bearing and shaft. The purpose is to prevent

(Structure of the invention) The power distribution device of the present invention is a power distribution device in which a housing is divided into a space around the shaft and a power distribution room by a bearing filled with lubricating oil and pivotally supporting a shaft. The structure includes a communication path that communicates between the power distribution room and the power distribution room.

(Example) An example of the present invention will be described below based on FIGS. 2 and 3. Note that the same parts as those in the prior art shown in FIG. 1 are given the same numbers, and redundant explanations will be omitted.

The power distributor of this embodiment includes a housing 1, a shaft 7, a ball bearing 6, and a metal bearing 5.
A communication passage 25 is provided in the housing 1 to communicate the gap 9 formed by the above-described structure with the power distribution chamber 16 that houses the rotor 14 and the like. In this embodiment, this communication passage 25 has a passage diameter of approximately 3 mmφ, and is formed in advance at the ball bearing fixed portion of the housing 1 by molding during die-casting of the housing 1 so as to communicate between the ball bearing bearing 6 and the housing 1. The ball bearing 6 is formed around the ball bearing 6 and is arranged around the ball bearing 6.

Next, the operation of the power distributor having the above structure will be explained.

When the engine is driven, the negative pressure inside the crankcase 4 increases as the rotational speed increases. Along with this, the gap 9 also tries to reach the same negative pressure as the inside of the crankcase 4 through the gap between the shaft 7 and the metal bearing 5, but since the gap 9 is communicated with the power distribution chamber 16 through the communication path 25, the power distribution Room 1
A state close to the atmospheric pressure within 6 is maintained. the result,
As shown in the graph of FIG. 3, the pressure difference between the gap 9 and the power distribution chamber 16 is extremely small compared to the conventional case, and the lubricating oil (grease) in the bearing 6 does not flow out into the gap 9. Furthermore, in this embodiment, the communication passage 25 can be formed during die-casting of the housing 1, so it can be manufactured easily and at low cost.

FIG. 3 is a graph showing the relationship between the engine speed and the internal pressure of each part, where a is the internal pressure in the power distribution chamber, b is the negative pressure in the crankcase, c is the internal pressure in the cavity in the conventional case, and d is the present example. It shows the internal pressure of the cavity at . As shown in Fig. 3, the differential pressure between the gap and the electrical distribution room was 450 mmAq (33 mmHg) at maximum in the conventional system, but in this example, it was 26 mmAq.
(1.9mmHg).

In the above embodiment, the diameter of the communication passage was set to 3 mmφ, but the diameter may be made smaller as long as the lubricating oil does not flow out. Also, although only one communication path is shown in Figure 2,
The present invention is not limited to this, and a plurality of them may be provided as necessary.
In this embodiment, the communication path is provided in the ball bearing fixed portion of the housing, but the communication path is not limited to this, and the communication path may be provided by connecting the gap and the power distribution chamber with a pipe or the like. Further, in this embodiment, a case has been described in which the application is applied to a power distribution device equipped with a ball bearing bearing and a metal bearing in the housing, but the present invention is not limited to this. Needless to say, the present invention can be applied to any power distribution device having a gap portion separated from the power distribution device by this bearing.

(Effects of the invention) As explained above, according to the invention, by providing a communication path that communicates the power distribution room and the cavity, the pressure difference between the power distribution room and the cavity can be made extremely small. It is possible to prevent the lubricating oil from leaking from the ball bearing that separates the power distribution room from the cavity, thereby avoiding seizure of the ball bearing, generation of abnormal noise, and sticking of the shaft, and greatly improving durability.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view showing a conventional power distributor, Figure 2 is a vertical cross-sectional view showing the power distributor of this embodiment, and Figure 3 is a diagram showing the relationship between the engine speed and the internal pressure of each part when the throttle valve is fully open. It is a graph showing a relationship. DESCRIPTION OF SYMBOLS 1...Housing, 6...Ball bearing bearing, 7...Shaft, 9...Gap, 16...Power distribution room, 25...Communication path.

Claims (1)

[Scope of utility model registration request] In a power distributor in which a housing is divided into a gap around the shaft and a power distribution chamber by a bearing filled with lubricating oil and pivotally supporting a shaft, a communication path is provided to communicate the gap and the power distribution chamber. A power distributor characterized by: