JPS6248977A - Fluid pump for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent a cavitation phenomenon from taking place in a fluid pump and enable high rotation of an engine by driving a fluid pump such as an oil pump, etc. loaded on a motorcycle, etc. via a centrifugal clutch and preventing the number of revolutions of said fluid pump from reaching above a defined value. CONSTITUTION:Hollow parts 3 which extend in a cross-from with a driving shaft 1 as the center, are formed in the internal gear 2 of a gear pump P as an oil pump. A clutch weight 4 and a balancing spring 5 which brings the clutch weight 4 into press contact with the outer peripheral surface of the driving shaft 1, are assembled in this hollow part 3. And, the internal gear 2 is connected to the driving shaft 1 by means of friction between the clutch weights 4 and the outer peripheral surface of the driving shaft 1, to drive the fluid pump P.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluid pump for an internal combustion engine, which is particularly suitable for being installed in a high-speed internal combustion engine mounted on a two-wheeled vehicle or the like.

``Prior Art'' Internal combustion engines are equipped with so-called oil pumps for supplying lubricating oil to various sliding parts such as pistons, flicks, and shafts.

For example, in internal combustion engines mounted on two-wheeled vehicles, gear pops are often used as oil pumps because they have a simple structure, are easy to downsize, and are inexpensive. The gear pump is normally driven in conjunction with the crank shaft of the engine.

``Problems to be solved by the invention'' By the way, high-speed internal combustion engines such as motorcycle engines have a very wide operating rotation range, so the applicable rotation range of hlin types such as the oil pump described above is very wide. G must be correspondingly wide.

However, this type of oil pump is known to suffer from gear locking when it exceeds a certain high-speed rotation range, causing noise and vibration. For example, in the case of an internal gear pump using a trochoidal tooth profile, as shown in FIG.
It is known that in a rotation range of 2 or more, the pump function deteriorates. Therefore, in the case of the gabbon shown in the figure, the range from the rotational speed Nl at which the required supply amount of pressure oil is generated to the rotational speed N2 at which cavitation occurs is the applicable rotational range in which the pop can be used effectively.

However, in the past, the oil pump itself was configured to simply rotate in conjunction with the rotation of the crankshaft, so the rotation speed of the oil pump increased in proportion to the engine rotation speed. When attempting to increase the engine speed and output, which is required further in the industry, the problem often occurred that the oil pump rotation speed exceeded the upper limit of its effective utilization range.

A possible solution to this problem would be to install a reduction gear, but in this case, a new problem would arise in which the oil pump would no longer produce the required amount of oil in the engine's low rotation range. I will know.

"Means for Solving the Problems" Therefore, in the present invention, in a fluid pump for an internal combustion engine that is driven in conjunction with the rotation of a crankshaft, a fluid pump is provided between a drive shaft of the fluid pump and a pump body. The configuration includes a centrifugal cranoid mechanism that cuts off the power input from the drive shaft only when the rotation speed reaches a predetermined number of revolutions or more.

"Function" When the rotational speed of the fluid pump reaches a predetermined rotational speed or higher, the centrifugal cranoid mechanism works and the rotational energy of the drive shaft is no longer transmitted to the pump body, and as a result, the pump body rotates at a higher speed. Never. Therefore, by setting the above predetermined rotational speed as the upper limit rotational speed at which the fluid pump can be used effectively, and by setting the centrifugal crudge mechanism to work at this point, the rotational speed of the fluid pump will always be within this effective rotational speed. This will keep it below the upper limit, so that even if the engine is rotated at higher speeds, a capacitance phenomenon will not occur in the fluid pot.

"Embodiment" Hereinafter, embodiments of the present invention will be explained with reference to the attached FIGS. 1 to 5. FIGS. 1 and 2 show the first embodiment of the present invention. In the figure, reference numeral 1 is a drive shaft linked to the crankshaft of the engine through gears, etc. This drive shaft I has a pump main body P that directly uses a part of the drive shaft I as its own pump shaft. When assembled, a fluid pump used as an oil pump is constructed.

In the embodiment, the pop body P is constituted by any type of internal gear pump including an internal gear 2 and an external gear 3 using a trochoidal tooth profile.

And between this pump body P and the drive shaft 1,
Only when the fluid pot reaches a predetermined rotational speed or higher, that is, when the rotational speed of the fluid pump reaches the upper limit of the rotational speed at which the fluid pump can be effectively used, is the power manually applied from the drive shaft 1 released. Equipped with a centrifugal clutch mechanism K for disconnection.

That is, in this embodiment, a cavity 3 is formed in the internal gear 2 and extends in a cross shape around the drive shaft 1, and a clutch weight 4 and a drive shaft for driving the clutch weight 4 are formed in the cavity 3. A counterbalance spring 5 is introduced to press against the outer circumferential surface of the shaft l, thereby forming a centrifugal clutch mechanism K. In the illustrated example, since the shape of the cavity 3 is cross-shaped to correspond to the contour of the internal gear 2, four sets of clutch weights 4 and counterweights 75 are installed. Here, since the type of each clutch weight 4 and the spring constant of the counterbalance spring 5 will affect the function of the centrifugal clutch mechanism, the settings for the weight and spring constant will naturally not be applied. It is determined according to the upper limit rotation speed of the fluid pump. In the figure, reference numeral 6 indicates a bearing.

In the fluid pump for an internal combustion engine equipped with the centrifugal clutch mechanism as described above, in the low rotation range of the engine, each clutch weight 4 is pressed against the outer peripheral surface of the drive shaft by the biasing force of the balance spring 5, and The driving force is transmitted to the pump body P by the γ retaining force. As the engine speed increases, the centrifugal force acting on the clutch weight increases, and the frictional force between the drive shaft and the clutch weight decreases, causing over-heeling. Then, when the rotational speed increases further and reaches the rotational speed of N2 in Fig. 5,
The clutch weight 4 separates from the outer peripheral surface of the drive shaft 1, and the driving force is no longer transmitted. In this state, internal gear 2
Since the rotational speed of the clutch weight 4 decreases, the clutch weight 4 comes into contact with the drive shaft I again, and the driving force is transmitted. In this way, when the rotational speed of the fluid pump exceeds a certain level, the centrifugal clutch mechanism K repeats activation and deactivation, resulting in a so-called hanging state (see FIG. 5). In this state, even if the engine speed increases further, the fluid pop rotation speed will not increase any further. Therefore, if the rotational speed at which the centrifugal cranochage mechanism K operates and the upper limit rotational speed at which the fluid pump can be effectively used are set to the rotational speed N2 in Fig. 5, high rotational speed and high output can be achieved. In such an engine, the fluid pump can be operated efficiently in an appropriate rotation range where cavitation does not occur.

Here, when considering the general operating conditions of the engine, the rotation speed of the fluid pump rarely reaches the rotation speed of N2,
Moreover, even if it is achieved, it is likely to be temporary, so it is extremely wise to equip a centrifugal clasp in this way.

3 and 4 show the first embodiment of the present invention. In this embodiment, the pump main body P itself has an independent structure with a pump shaft, and the pump shaft 7 and the drive shaft I are connected to each other. The configuration includes a centrifugal cranoid machine + and ¥tK in between. That is, centrifugal cranoid machine tM K
is equipped with a hollow disk-shaped rotating body 8 in which a clutch weight 4 and a balance spring 5 are incorporated, and a drive shaft 1 is rotatably inserted into the center of the rotating body 8, and the outer peripheral surface of the drive shaft 1 is inserted into the center of the rotating body 8. The clutch weight 4 (1iii) is in pressure contact with the rotating body 8, and a boss portion 9 coaxial with the drive shaft l is provided on the rotating body 8 and protrudes toward the pump main body P side, and the pump is inserted into the boss portion 9. A shaft 7 is inserted and fixed there, so that the drive shaft 1 and the bomb shaft 7 are coaxially connected.

The action and effect of the fluid pump according to this embodiment are almost the same as those of the previous embodiment, and since the pump main body P has an independent configuration with a pump shaft 7,
Maintenance and replacement of the pump body P is easy, which is convenient from a maintenance standpoint.

"Effects of the Invention" As explained above, in the present invention, in the fluid pump for an internal combustion engine that is driven in conjunction with the rotation of the crankshaft, there is a gap between the drive shaft of the fluid pump and the pump body. Since the configuration includes a centrifugal clutch mechanism that cuts off the power input from the drive shaft only when the fluid pump reaches a predetermined rotation speed or higher, the centrifugal clutch mechanism operates in the upper limit rotation range where the fluid pump can be effectively used. By simply setting these settings, the fluid pump can be operated efficiently in an appropriate rotation range where cavitation does not occur, even in engines designed for high rotation and high output. Since it operates in the same manner as before even in the low rotation range, it has the advantage of greatly expanding the applicable rotation range of the fluid pump.

[Brief explanation of drawings]

1 and 2 are sectional views showing a first embodiment of the present invention, FIGS. 3 and 4 are sectional views showing a second embodiment of the present invention, and FIG. 5 is a sectional view showing a fluid flow according to the embodiment. FIG. 6 is a characteristic diagram of a fluid pump in a conventional example. L: Drive shaft, P: Pump body, K: Centrifugal clutch mechanism. Figure 3 Figure 4

Claims (1)

[Claims] In a fluid pump for an internal combustion engine that is driven in conjunction with the rotation of a crankshaft, an input signal is input from the drive shaft between the drive shaft of the fluid pump and the pump body only when the fluid pump reaches a predetermined rotation speed or higher. A fluid pump for an internal combustion engine, characterized in that it is equipped with a centrifugal clutch mechanism that cuts off the power generated by the engine.