JPH0488246A - Coreless torque converter - Google Patents

Abstract

PURPOSE:To improve torque converter characteristics such as torque ratio and efficiency by changing the shape which is advantageous in cost by setting the dimension in the axial direction of a turbine runner shorter then the dimension in the axial direction of a pump impeller. CONSTITUTION:The dimension L in the blade part axial direction of a turbine runner 4 is set shorter than the dimension L0 in the blade part axial direction of a pump impeller 2. Accordingly, the center of the swirl of the circulation flow necessarily shifts to the pump impeller 2 side by the reduction portion of the dimension in the axial direction of the turbine runner 4. Accordingly, when the dimension in the axial direction of the turbine runner and the dimension in the axial direction of the pump impeller are set equal, the center of the swirl of the circulation flow deflects to the turbine runner side, while in the case according to the present invention, the flow approaches the part where blades are collected, because of the shift of the center of the swirl of the circulation flow to the pump impeller 2 side. Accordingly, the oil which circulates inside easily flows out from the rear edge of the stator 6, and the flow which flows into the pump impeller 2 or the turbine runner 4, passing through the upper part of the stator 6 is suppressed, and the stator 6 acts effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a coreless torque converter that does not have a core in the portion where each blade is assembled.

(Prior art) Conventionally, as a coreless torque converter, for example, S
The one described in AE Paper No. 861213 is known.

As shown in Fig. 5, this conventional source has three elements: a pump impeller 01, a turbine runner 02, and a stator 03, and there is no core in the part where these blades are assembled. A coreless torque converter called a type is shown.

(Problem to be Solved by the Invention) However, in such a coreless torque converter, a member that restricts the flow and forms a flow path, which corresponds to the core of a torque converter that is used in general passenger cars, is required. Because it does not have a torque converter, the center of the vortex of the circulating flow is biased toward the turbine runner side, resulting in a lower stall torque ratio and efficiency than a torque converter with a core, making it difficult to apply to small displacement vehicles, and making it difficult to start and stop. There has been a problem in that fuel efficiency deteriorates under repetitive driving conditions.

The present invention was made with attention to the above-mentioned problems, and it is possible to improve the torque ratio and efficiency by changing the shape of a coreless torque converter, which is advantageous in terms of cost. The objective is to improve torque converter characteristics.

(Means for Solving the Problems) In order to solve the above problems, in the coreless torque converter of the present invention, the axial dimension of the turbine runner is set shorter than the axial dimension of the pump impeller.

In other words, in a coreless torque converter that has three elements, a pump impeller, a turbine runner, and a stator, and does not have a core where these eight blades are assembled, the axial dimension of the turbine runner is the axial dimension of the pump impeller. It is characterized by being set shorter.

The axial dimension of the aforementioned two turbine runners is preferably set within a range of 0.5 to 0.9 times the axial dimension of the pump impeller.

(Function) When operating a coreless torque converter installed in a passenger car, etc., the axial dimension of the turbine runner is set to be shorter than the axial dimension of the pump impeller. The center of the vortex of the circulating flow inevitably moves toward the pump impeller.

In other words, if the axial dimensions of the turbine runner and the pump impeller are set to be the same, the center of the vortex of the circulating flow will be biased toward the turbine launch side, whereas the center of the vortex of the circulating flow will be biased toward the turbine launch side. By moving toward the pump impeller, it will approach the part where eight blades are gathered.

As a result, the oil circulating inside is more likely to flow out from the trailing edge of the stator, and the flow passing through the upper end of the stator and flowing into the pump impeller or turbine runner is suppressed, so that the stator works effectively.

(Example) First, the configuration will be explained.

FIG. 7 is a sectional view showing the coreless torque converter of the embodiment.

The coreless torque converter of the embodiment has a pump impeller 2 coupled to a converter cover 1 into which engine driving force is input, and is arranged at a position opposite to the pump impeller 2, and a transmission input shaft (not shown) is connected through a turbine hub 3. It has three elements: a turbine runner 4 that is connected to the pump impeller 2, and a stator 6 that is disposed on the inner diameter portion between the pump impeller 2 and the turbine runner 4 and is provided in a case (not shown) via a one-way clutch 5. These 8 wings 2.
The part where 4.6 is gathered only has the wing tips close to each other and does not have a core.

The pump impeller 2 has exactly the same shape as that used in the conventional coreless torque converter shown in FIG.

The turbine runner 4 is designed based on the turbine runner used in the conventional coreless torque converter shown in FIG. 5, and is formed by crushing at a constant ratio in the axial direction.

The stator 6 is designed based on the stator used in the conventional coreless torque converter shown in FIG. It is formed by crushing at a certain ratio.

Note that the stator 6 has a larger number of stator blades than the case shown in FIG. 5 because the area of each blade is reduced.

Due to this change in the shape of the turbine runner, the turbine runner 4
The axial dimension of the blade portion excluding the shell portion of the pump impeller 2 is the axial dimension of the blade portion excluding the shell portion of the pump impeller 2. It is set shorter.

Next, the effect will be explained.

Considering its structure, a coreless torque converter can be said to be a modification of a fluid coupling in which only a pump impeller and a turbine runner are arranged facing each other, and the flow of internal fluid is also considered to be similar to that of a fluid coupling.

Previously published “Design of Fluid Transmission Devices!!” (co-authored by Tomoo Ishihara and others; published by Ohm Publishing Co., Ltd. in 1967), pages 23 and 1
According to Figure 1, fluid coupling has a medium speed ratio.

Even at low speed ratios, the center of the vortex of the circulating flow is biased towards the turbine runner side. Incidentally, in the case of normal torque converters (including coreless converters), the situation where the converter separates into a liquid phase and a gas phase at a high speed ratio does not occur because the inlet pressure is set to about 4 kg/am2.

Therefore, in the case of a coreless torque converter as shown in FIG. 5, the circulating flow is as shown in the flow pattern of FIG. 2, by analogy with the circulating flow in a fluid coupling. That is, a significant portion of the flow that enters the stator passes through the upper end of the stator and flows into the pump impeller or turbine runner. This is the cause of low torque ratio and low efficiency.

On the other hand, in the coreless torque converter of the example,
The axial dimension of the blade portion of the turbine runner 4 is the axial dimension of the blade portion of the pump impeller 2. Because it is set shorter,
Reduced axial dimension of turbine runner 4 (L-L,)
, the center of the vortex of the circulating flow inevitably moves toward the pump impeller 2 side.

In other words, if the axial dimensions of the turbine runner and the pump impeller are set to be the same, the center of the vortex of the circulating flow will be biased toward the turbine runner, as shown in Figure 2. , pump impeller 2 in the center of the circulating flow vortex
By moving to the side, it approaches the part where eight blades are gathered, and the flow pattern becomes as shown in Fig. 3.

As a result, the oil circulating inside becomes easier to flow out from the rear edge of the stator 6, and the flow passing through the upper end of the stator 6 and flowing into the pump impeller 2 or turbine runner 4 is suppressed, and the stator 6 is effectively work.

As explained above, in the coreless torque converter of the embodiment, the effects listed below can be obtained.

■ The axial dimensions of the turbine runner 4 are compared to the pump impeller 2.
Since it is set shorter than the axial dimension of , it is possible to improve the torque converter characteristics such as torque ratio and efficiency while making a cost-effective shape change without increasing the number of parts.

By the way, Figure 4 shows the turbine runner aspect ratio L/L.

(See Figure 1) Performance test results of coreless torque converters are shown, with L/L = 1. Compared to the conventional structure of O, L/Lo=0.9 and L/L,=0.
It can be seen that in the case of the example structure numbered 8, the torque ratio and efficiency are improved.

As a result, it can be applied to small displacement vehicles, and
The power performance and fuel efficiency of the vehicle to which it is applied are improved.

■ Axial dimension of turbine runner 4 and pump impeller 2
This was achieved by flattening the turbine runner 4 and changing the shape of the stator 6 accordingly to create a difference in the axial dimension of the pump impeller 2, which required a design change while keeping its conventional shape. It is also advantageous in terms of design and manufacturing costs.

Although the embodiment has been described above based on the drawings, the specific configuration is not limited to this embodiment.

For example, in the embodiment, the difference between the axial dimension of the turbine runner and the axial dimension of the pump impeller was shown as being achieved by flattening the turbine runner, but it could also be achieved by changing the shape of the pump impeller. Of course, it is also possible to change the shapes of both the turbine runner and the pump impeller to obtain a dimensional difference in the axial direction.

In the embodiment, an example was shown in which the axial dimension of the turbine runner was approximately 0.8 times the axial dimension of the pump impeller.
The magnification of this axial dimension is preferably set in the range of 0.5 to 0.9 times.

In other words, if it is 0.9 times or more, sufficient movement of the center of the vortex of the circulation flow will not be realized, and no improvement in torque ratio or efficiency can be expected, and if it is less than 0.5 times, the flow condition of the turbine runner will be poor. The capacity may drop too much, or the number of blades may increase, making manufacturing difficult.

Also in the case of the example, the turbine runner oblateness L/Lo
It is preferable to set it in the range of 0.5 to 0.9 times.

(Effects of the Invention) As explained above, in the present invention, in a coreless torque converter that does not have a core in the part where each member is assembled, the axial dimension of the turbine runner is Since the dimensions are set short, it is possible to improve the torque converter characteristics such as torque ratio and efficiency by changing the shape which is advantageous in terms of cost.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a coreless torque converter according to an embodiment of the present invention, FIG. 2 is a diagram showing a flow pattern in a conventional coreless torque converter, and FIG. 3 is a diagram showing a flow pattern in a coreless torque converter according to an embodiment. Figure shown, 4th
The figure is a characteristic diagram showing the performance test results of the coreless torque converter, and FIG. 5 is a sectional view showing the conventional coreless torque converter. 1--Converter cover 2--Pump impeller 3--Turbine hub 4--Turbine runner 5--One-way clutch 6--Stator

Claims (1)

[Claims] 1) Three components: a pump impeller, a turbine runner, and a stator.
A coreless torque converter that has elements and does not have a core in the part where these blades are assembled, characterized in that the axial dimension of the turbine runner is set shorter than the axial dimension of the pump impeller. . 2) The coreless torque converter according to claim 1, wherein the axial dimension of the turbine runner is set in a range of 0.5 to 0.9 times the axial dimension of the pump impeller.