JPS58152940A - Variable speed fluid coupling - Google Patents

Abstract

PURPOSE:To reduce the resistance loss of a rake pipe, by forming a side face sectional shape in a point end part of the rake pipe in such a manner that an angle of a side face with the vertical direction increases toward the side of a discharge part from the side of the point end part. CONSTITUTION:A side face section of the point end part 17 of a rake pipe is formed to a shape such that an angle alpha of a side face 19 with the vertical direction 14 is increased toward the side of a discharge part 9 from the side of the part 17. In case of forming the side face of such section, a plane shape spread from an opening 18 along a tail 20 is formed such that the face 19 decreases side pressure in the outside for the flow direction of fluid. Accordingly, a scattered jet flow from the face 19 of the rake pipe is extremely reduced to remarkably decrease loss resistance of the rake pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable speed fluid coupling used for thermal power plants and the like.

Figure 1 shows an overview of this woodcutter's variable speed fluid coupling.
Rotation of the nine-point/bell impeller 2 connected to the input shaft 1 applies centrifugal force to the hydraulic oil, which flows into the launch impeller 3 and transmits the power from the input shaft 1 to the output shaft 4 . At this time, the scooping tube 8 inserted diagonally with respect to the rotating shaft into the scooping tube chamber 5 formed by the partition plate 6 and the casing 7 is moved in the radial direction to scoop up the rotating liquid in the scooping snow amount 5. Controls the rotation speed of the output shaft 4.

Recently, high transmission efficiency has been required for this type of variable speed fluid coupling, but the internal efficiency of the fluid coupling depends only on the speed ratio, and in order to improve the internal efficiency, it is necessary to Additional losses such as scoop pipe resistance loss and bearing loss must be minimized as much as possible.

The shape of a conventional scoop pipe that affects the scoop pipe loss will be explained with reference to FIGS. 2 and 3.

In FIGS. 2 and 3, the scoop tube 8 consists of a discharge part 9 and a tip part 10 having an opening 11 in the upper surface.

By the way, according to the inventor's model experiments, in the conventional scoop tube structure, as shown in FIG. The amount of splashback from the side surface 12 is large, and when the rake ratio is 50%, a considerable amount of hydraulic oil is discharged to the outside from the gap between the output shaft 4 and the casing 7 without passing through the rake pipe. There was found.

Further, the turbulence of the flow at the tip 10 of the scoop tube is caused by the large collision force of the fluid flow against the side surface 12 of the tip of the scoop tube, and the fluid becomes a jet fi 13 and enters the air as shown in FIG. 9. It was found that this occurs due to splashing. The side surface shape of the scoop tube tip 10 is formed so that the angle α between the side surface 12 and the vertical direction 14 is approximately equal on the tip 10 side and the discharge section 9 side, as shown in FIGS. 5 and 6. ing. When formed with such a side cross-sectional shape, the seventh
As shown in the figure, the planar shape developed from the opening 11 of the tip portion 10 to the rear tail 15 is formed such that the side pressure on the side surface 12 on the outside is large with respect to the fluid flow direction (in the direction of the arrow shown in the figure). . Side surface 12 and horizontal direction 16 at this time
Let the angle of the angle β be positive.

In this way, when the side pressure generated on the outside of the scoop pipe 8 is large, that is, when β is positive, the resistance loss of the scoop pipe 8 is also large, and the transmission efficiency of the entire joint eventually decreases.

The present invention was made in consideration of the inventor's experimental results that the resistance loss of the scoop tube is caused by the turbulence of the fluid at the tip of the scoop tube. The purpose is to provide a fluid coupling.

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

8 to 12, the same reference numerals as in FIGS. 2 to 7 indicate the same parts.

Reference numeral 17 denotes a tip end of a scoop tube which has an opening 18 on the upper surface and is fixed to the discharge portion 9. The side cross-sectional shape of the tip end portion 17 of the scoop tube has a side surface 19 as shown in FIGS. 10 and 11.
The angle α between the distal end portion 17 and the vertical direction 14 increases from the distal end portion 17 side toward the discharge portion 9 side.

When formed in such a side cross-sectional shape, the planar shape developed from the opening 18 along the rear tail 20 as shown in FIG. It is formed. Side 1 at this time
The angle β formed by 9 and the horizontal direction 16 is negative. This β is
According to the model experiment results, good data are obtained within the range of 0 to 301'. However, if β is too large, the scoop pipe becomes shallow and the rake rate decreases, so taking these into consideration, the optimum value is actually between Vio° and 10°. Therefore, β may be set to 00 to make the side surface 19 parallel to the flow, or β may be formed to be negative in the range of lOo.

Further, the tip portion 17 of the scoop tube is located at the center l1i of the scoop tube.
21.

As a result of conducting model experiments on the shape of the scoop tube as described above, the amount of jets bouncing off the side surface 19 of the scoop tube was extremely reduced, and the loss □ resistance of the scoop tube was significantly reduced. Sukon 411 bjl effect - I'm noticed. At this time, a flow having a free surface exists on the side surface 19 outside the tip 17 of the scoop tube, but the side surface 19 is formed in a shape that makes it difficult for the flow to collide with it, and the side pressure becomes small, so the fluid flow is less turbulent. Therefore, since the amount of p that is bounced back from the opening 18 of the scoop tube is reduced, the rake rate is significantly improved.

FIG. 13 shows another embodiment of the scoop pipe in the variable speed fluid coupling of the present invention. In FIG. 13, the same reference numerals as in FIG. 8 indicate the same parts.

The side shape of the most extreme surface 22 of the scoop tube tip 17 is as follows:
It is formed at an acute angle so as to cause the flow of the rotating fluid to occur at a point 23 on the most extreme surface 22.

In other words, the angle r formed between the most extreme surface 22 and the vertical direction 14 becomes smaller as the angle r between the most extreme surface 22 and the vertical direction 14 increases from the opening 18 toward the rear end 20.
It is formed so that it can go from extreme to extreme.

The angle r is determined by the flow rate of the hydraulic oil. For example, when the flow rate is large, if the angle r is made small, the most extreme surface 22 of the scoop tube tip 17 will be immersed in the fluid, so it is difficult to avoid peeling. Multiple phenomena will no longer occur. Taking these into consideration, the immersion depth is calculated in advance, and the angle [r] is determined as appropriate to enable the peeling phenomenon.

By forming the distal end surface 22 of the scoop tube in this way, it is possible to cause a gouge phenomenon in the fluid flow at the point 23 on the distal end surface 22 of the scoop tube, and as a result of the experiment,
The resistance force generated when the scoop pipe scoops up the working fluid is reduced by approximately 30
% can be reduced.

FIG. 14 shows still another embodiment of the rake member in the variable speed fluid coupling of the present invention.
! The same reference numerals as in FIG. 8 indicate the same parts.

In FIG. 14, the scoop tube tip 17 is inserted into the scoop tube and fixed to the discharge part 9 so as to be perpendicular to the direction of the rotation axis.

By arranging the scoop pipe tip 17 in this way,
Due to the reduced impingement of the fluid flow against the side surface 19 of the scoop tube tip 17, the loss resistance of the scoop tube is further reduced.

According to the variable speed fluid coupling of the present invention, the side cross-sectional shape of the tip of the scoop tube is formed such that the angle formed between the side surface of the scoop tube and the vertical direction increases from the tip side toward the discharge section side. Therefore, the resistance loss of the scoop pipe can be reduced, and the transmission efficiency of the entire joint can be greatly improved.

In the same embodiment of the present invention, the opening at the tip of the scoop tube is formed into a substantially triangular shape, but the same effect as described above can be obtained even if the opening is shaped into an elliptical shape or the like.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of a conventional variable speed fluid coupling, Figure 2 is a side view of a scoop pipe in a conventional variable speed fluid coupling, Figure 3 is a plan view of Figure 2, and Figure 4 is a conventional scoop pipe. 5 is a sectional view taken along the line 5-5 in FIG. 3, FIG. 6 is a sectional view taken along the line 6-6 in FIG. 3, and FIG. 8 is a side view of the scoop tube in the variable speed fluid coupling of the present invention. FIG. 9 is a plan view of FIG. 8.
Figure O is a sectional view taken along the line 10-10 in Figure 9, Figure 11 is a sectional view taken along the line 11-11 in Figure 9, and Figure 12 is a developed plan view taken from the opening at the tip of the scoop pipe to the rear. , FIG. 13 is a side view showing another embodiment of the scoop pipe in the variable speed fluid coupling of the present invention, and FIG. 14 is a plan view showing another embodiment of the scoop pipe in the variable speed fluid coupling of the present invention. . 9... Discharge part, 17... Scoop pipe tip, 18...
- Opening, 19... side, 20... rear. fJ/ Figure\iz Figure[4 Figure 5\:J6Figure\J 7 Figure'jfJ3 Figure viq Figure\Is 73 Figure g

Claims (1)

[Scope of Claims] 1. In a variable speed fluid coupling having a pump impeller and a turbine impeller and having a structure in which a scoop tube consisting of a tip end and a discharge section moves obliquely with respect to the rotational axis direction, the tip of the scoop tube A variable speed fluid coupling characterized in that the cross-sectional shape of the side surface of the part is formed such that the angle formed by the side surface and the direction perpendicular to the side surface becomes larger as K goes from the tip end side to the discharge part side. 2. The variable speed fluid coupling according to claim 1, wherein the side surface of the tip end of the scoop tube tip is formed at an acute angle. The variable speed fluid coupling according to claim 1 or 2, characterized in that: