KR20080091024A - Axial ventilator, especially for the cooling system of a rail vehicle - Google Patents

Abstract

An axial ventilator for a cooling system in a rail vehicle is provided to reduce a noise by making a sweep angle between a connection line and a tangential line meet a non-linear function. An axial ventilator for a cooling system in a rail vehicle comprises a blade wheel(1) having one hub and plural blades(3) such as sickle blades, and a connection line wherein the center of sections is three-dimensionally bended. The sweep angle between the connection line and a tangential line meets a non-linear function.

Description

Axial ventilator for cooling system of rolling stock {AXIAL VENTILATOR, ESPECIALLY FOR THE COOLING SYSTEM OF A RAIL VEHICLE}

The present invention relates to an axial ventilator, in particular an axial ventilator for railway vehicles.

Axial flow ventilators have long been known. There are many publications. See eg US 4 358 245, US 4 569 631, US 4 569 632, US 4 684 324.

The latest blade form is a sickle form. The individual blades bend forward when viewed in the direction of rotation of the blade wheel. By cutting the blades to form cylinder sections, and connecting the centers of the individual cylinder sections, all the centers form one connecting line.

Recently, the problem of ventilator noise is very important. Much effort has been made to lower the noise level. US 4 358 245 describes a ventilator blade wheel with a collar fixed to the outer end of the blade. The blades bend badly forward. The blade angle increases along the radius from inside to outside.

In addition to lowering the noise level, efforts are made to increase efficiency.

As the demand for environmental protection grows, the solutions known so far are no longer sufficient to reduce the noise load.

It is an object of the present invention to provide an axial ventilator which significantly lowers the noise level produced during operation and has as much improved efficiency as possible than known ventilators.

The problem is solved by the features of claim 1.

The inventor assumes a blade wheel with sickle blades. The blade is bent forward. The connecting line extends in three dimensions. The blades are formed such that the sweep angle, ie the angle formed by the connecting line and the tangents lying thereon, is a nonlinear function along the radius of the blade.

Second or third order or other functions are considered.

The ventilator with blades according to the invention has been shown to have a sound level of 4 to 8 dB lower than so far. The efficiency of the ventilator is also satisfactory. The efficiency is higher or at least equal to the efficiency of the ventilators known so far.

The present invention will be described in detail with reference to the accompanying drawings.

The blade wheel shown in FIGS. 1 and 2 has a hub 2 and a plurality of blades 3. Blades are sickle blades. The blades are bent forward (see direction of rotation 4 of the blade wheel).

A number of cross sections from one of the blades is given as a cylinder cross section (see virtual cutting lines 3.1 to 3.8). When the centers of the cutting lines are connected to each other, a connecting line 5 is given. The connecting line 5 is not only curved in the projection plane, but also perpendicular to the projection plane. Thus, they bend in three dimensions.

Forming a tangent to the connecting line 5 at several points in the radius gives the angle δ, the so-called sweep angle, respectively. The sweep angle δ varies with the radius.

3 shows a curve of the sweep angle δ relative to the radius. In this case the curve follows a quadratic function. The angle δ at the hub is -55 degrees and the angle at the outer circumference is 55 degrees.

Therefore, the curve of the sweep angle δ is nonlinear. The curve may extend in accordance with a function different from the quadratic function, such as a cubic function.

4 shows a blade wheel corresponding to a specific embodiment. See also hub (3) and blade (3). Blades are sickle blades. These bend forward and correspond to the blades according to FIGS. 1 and 2 in all important details. Here too the sweep angle with respect to the radius extends according to the quadratic function (not shown in detail).

The motor support 6 shown in FIG. 5 is designed for the blade wheel shown in FIG. 4. The motor support 6 may be arranged coaxially with respect to the blade wheel, respectively, on the suction side or the pressure side of the blade wheel. The motor support 6 is fixed in the assembled state.

The motor support 6 comprises a central disk 6. 1, a circumferential collar 6. 2 and strips 6. 3 concentric with it. The strips 6.3 are fixed to the central disk 6. 1 and the circumferential collar 6. They are arranged in the form of dashed lines with respect to the central disk 6.1. The central disk supports the drive motor, not shown, of the ventilator.

6 shows a blade wheel 2 associated with a motor support 6. Both are arranged coaxially with each other. In this case, the motor support 6 is arranged on the suction side of the blade wheel 1. A motor, not shown, is assembled on the motor disk 6.1.

The inventor has found that the arrangement of the motor support 6 in relation to the blade wheel 1 is important for the noise level and the efficiency. The arrangement should be chosen such that the angle α between the individual strips 6.3 and the associated blades 3 underlying them is as large as possible, in particular in the radially outer region. This not only advantageously affects the noise level occurring during operation of the ventilator but also its efficiency.

By combining the motor support 6 with the blade wheels in reverse, if the strip 6. 1 is directed in the reverse direction, the angle α can be very small or even zero. The angle α will be much smaller in the radially outer region.

It is preferable that the actuating blade does not have a circumferential collar, so that no connecting member connecting the blade peaks to each other is necessary. In this case, the ends of the blade 3 protrude freely.

1 shows a portion of a blade wheel seen in the direction of the axis of rotation;

2 is a side view of FIG. 1;

3 shows a curve of sweep angle versus radius.

4 is a perspective view and a plan view of the blade wheel;

5 is a motor support for assembling with a blade wheel.

6 is a motor support coupled with a blade wheel.

Claims (5)

As an axial flow ventilator for a cooling device of a railway vehicle 1.1 comprises a blade wheel 1 having a hub 2 and a plurality of blades 3, 1.2 the blades 3 are sickle blades, 1.3 the center of the cross-sections 3.1 to 3.8 form a three-dimensionally curved connecting line 5, 1.4 The swept angle (δ) between the connecting line (5) and the tangent to it, shown for the radius of the blade wheel (1), follows a nonlinear function, the axial ventilator for the cooling device of a railway vehicle. An axial flow ventilator for a cooling system of a railway vehicle according to claim 1, wherein said sweep angle (δ) follows a quadratic function. An axial flow ventilator for a cooling system of a railway vehicle according to claim 1, wherein said sweep angle (δ) follows a cubic function. The method according to any one of claims 1 to 3, 4.1 The blade wheel 1 is assigned a motor support 6 comprising a central disk 6. 1, a circumferential collar 6. 2 and a plurality of strips 6. 3 connected thereto, 4.2 The strips 6.3 are arranged in the form of a dashed line with respect to the central disk 6.2. 4.3. Said strips (6.3) are arranged in an axial direction such that they form an angle as large as possible with the front edge of the blade (3). 5. The axial ventilator of claim 1, wherein the radially outer ends of the blades of the blade wheels protrude freely. 6.

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