1. Field of the Invention
The invention relates to a fan, in particular, a fan for electrical and electronic devices. The fan comprises a hub and a fan housing connected to the hub, wherein the fan housing delimits an air passage provided in the fan in the outward direction. The fan further comprises a fan wheel which is arranged rotatably in the air passage and a motor arranged on the hub for driving the fan wheel. An electrical connection is provided which extends from the motor to the fan housing and comprises at least one flexible line.
2. Description of the Related Art
A so-called strain relief must be provided for such flexible lines. Usually, the flexible lines are connected by soldering to a printed circuit board of the motor. This solder connection cannot be stressed permanently; it can be damaged or destroyed by mechanical strain or tension. Therefore, such a tension or strain must be stopped before it reaches the printed circuit board.
There are different possibilities of realizing such a strain relief. For example, the flexible line can be deflected by a certain angle at least at two locations so that the strain is absorbed in the area of these deflections and the rearward portion of the flexible line extending beyond the deflection locations to the motor remains free of strain. In this way, it is prevented that during transport, during mounting, and during operation of such a fan, a tensile force or strain will be transmitted via the flexible line into the interior of the fan and onto the contact locations or soldering locations or plug contacts and onto the printed circuit board of the motor.
In order to permanently ensure such a strain relief, it must be ensured that the flexible line is secured or fixed at this deflection location.
In the case of fans with plastic housings, such a strain relief is achieved, for example, in that the flexible line is threaded into stationary or fixed deflection means. When threading it into locking cams or narrow portions, the flexible line is secured therein permanently.
In the case of metal housings, the flexible line is threaded through an opening in the flange and then fixed by insertion of a holder and is permanently secured in this way. When a plug is connected to the flexible line, the plug must not be greater than the opening within the flange because otherwise it cannot be threaded through the opening. In such a case, mounting is carried out such that either the plug is connected to the flexible line only after the flexible line has been mounted or the flexible line provided with the plug is soldered to the printed circuit board of the motor only after mounting of the flexible line; both methods prolong the time required for assembly and increase costs for assembly.
It is therefore an object of the present invention to provide a fan configuration which eliminates the aforementioned problems.
In accordance with the present invention, this is achieved in that a cutout is provided within the fan housing to which the at least one flexible line extends and in which a holding member can be locked in place, wherein the holding member in the mounted state deflects the at least one flexible line at least at one location about a predetermined minimum angle and, in this way, effects strain relief on the part of the flexible line extending to the motor.
By employing a holding member which can be locked in place on the fan housing, it is possible to place the flexible line, before mounting of this holding member, in a simple way into a recess or cutout provided for this purpose, so that it must not be threaded, and to deflect the flexible line only upon mounting of the holding member. After mounting of the holding member, the flexible line—without plug—which has been fixed in place in this way, can only be removed from the strain relief device in that the holding member is removed or in that the flexible line is removed (unthreading) over its entire length out of these deflections. A flexible line which has a plug attached thereto can be removed from the strain relief device only in that the holding member is removed again from its locking position. It is thus very advantageous that the flexible line must not be threaded into the at least one deflection device; instead, it is deflected upon insertion and locking of the holding member and, in this way, the deflection required for strain relief is automatically provided in the locked position of the holding member.
Preferably, this is realized in that the holding member in the locked state deflects the flexible line at two deflection locations about a predetermined minimum angle in order to effect the strain relief. This provides a very safe strain relief without this requiring extra expenditure for assembly. Moreover, the present invention enables that the time for assembly becomes independent of the length of the flexible line and that even flexible lines provided at their end with a plug can be mounted entirely without problems.
A very advantageous embodiment is provided in that a support member for at least one flexible line is provided on the hub and supports the flexible line in the area of the air passage at least partially. Such a support member provides the advantage that the flexible line must not be threaded at this location but can be simply placed onto the support member; this simplifies mounting significantly.
The fan 20 has a motor 36 whose stator in FIG. 1 through
The shape of the fan vanes 40 is matched to the conical shape of the inner side of the pipe 24. The fan wheel 38 has a center part 39 having a truncated cone shape at its exterior side, as illustrated in FIG. 2. It forms together with the truncated cone shaped pipe 24 an air passage 41. The air passage has a smaller diameter at the intake side 32 than at the exit side 34. Also, the fan wheel 38 has a smaller diameter at the intake side 32. The diameter increases in the direction toward the exit side 34.
For mounting the motor 36, a fastening flange 44, which is also referred to in the following as a hub, is provided and connected by thin securing stays 46 to the fan housing 22. This is realized preferably by screw connections 48 indicated in FIG. 1 through FIG. 3. The outer or free ends of the stays 46 have widened portions 21 which fit in corresponding recesses 23 of the fan housing 22 (see FIGS. 1 through 3). A positive locking guide is provided: Two diametrically opposed recesses 23 have a guide member in the form of a centering pin 25, respectively, which locks positively in a corresponding complementary guide member (cutout) 27 of the correlated widened portion 21 and, in this way, centers the hub 44 exactly within the conical pipe 24. The screws 48 serve thus only for fastening but not for centering. This is a very advantageous type of connection, also with respect to automated manufacture.
Moreover, a shortened stay 50 is provided on the hub 44 whose function it is to support the flexible electric connecting line 52 of the motor 36. The electric line 52 can be configured, for example, as a multi-strand plastic-sheathed cable. As illustrated clearly in
The motor 36 is fixedly connected by non-illustrated securing pawls to the hub 44. The stays 46, 50 are preferably formed as unitary parts of the hub 44. In
The connecting line or cable 52 of the fan 20 usually contains several flexible insulated lines, preferably, so-called litz wires, each comprised of a plurality of thin wires which are embedded in an insulating material. In the home, such flexible lines or litz wires are used, for example, in the form of multi-strand plastic-sheathed cables for electrical connections of electric irons or television sets. The fan 20 requires two lines for supplying its operational voltage. In many cases, extra lines are provided, for example, for a tachometer generator signal or for an alarm signal. All of these flexible lines or cables must be attached quickly and primarily securely when mounting the fan 20; this will be explained in the following.
As shown in
At the exit side 34 of the truncated cone-shaped pipe 24 a lateral recess 70 is provided which is positioned substantially on an imaginary extension of the shortened stay or support 50 so that the flexible line or cable 52, which is guided in the groove 53 of the stay 50, can be placed subsequently through the cutout 70 and through the cutouts 28A and 26A without having to be threaded anywhere. This type of guiding of the line 52 is clearly illustrated in
As illustrated, the flexible line 52 extends from the motor 36 via the groove 53 and through the cutout 70 of the truncated cone-shaped pipe 24 to the two cutouts 28A, 26A of the flanges 28 and 26. This is illustrated also in
The holding member 80 has a substantially flat base part 82 which is illustrated in
In
The roof part 90 is also connected at a location provided approximately at its center by means of a deflection member 96 to the base part 82. As illustrated in
To the right of the deflection member 96, the roof part 90 has a raised section 98 which, according to
As illustrated in
By means of the deflection member 96, the flexible line 52 is moved in
Because of the two deflection locations 106, 108 of
Advantages of the invention result primarily from the following features: Before mounting the holding member 80, at least one flexible line 52 can be inserted directly into the corresponding openings of the fan 20, i.e., it is no longer required to thread the line 52; the line 52 is deflected at the locations 106,108 once the holding member 80 is mounted.
After mounting, the flexible line 52, inasmuch as no plug is connected thereto, can be removed only by unthreading its entire free length or by demounting the holding member 80 from the strain relief.
A flexible line 52 to which a plug is attached can be removed only by releasing the holding member 80 from the strain relief.
The insertion and locking of the holding member 80 deflects the at least one flexible line 52 at the same time at two locations 106,108 (
Inasmuch as several flexible lines 52 are used, a significant labor simplification is realized by the two cutouts 26A, 28A into which these lines 52 are introduced before mounting as shown in FIG. 1. When the lines 52 have been inserted, subsequently the holding member 80 can be inserted and locked. However, the invention can be realized, for example, without the cutout 26A because strain relief can be obtained also by deflection in this case.
The time for assembly is independent of the length of the flexible line(s) 52.
Flexible lines having a plug at their free end can be mounted without problems in the described way.
By means of the stay 69 provided on the housing 22, unthreading of the flexible line 52 in the locked state of the holding member 80 is not possible or possible only with difficulties.
Threading of the flexible line 52 in stationary deflection means on the housing is eliminated by the invention so that the time for assembly is shortened correspondingly.
In place of the illustrated individual flexible lines 52, the invention can also be employed in the same way with several flexible lines or lines which are enclosed in an insulating hose and require a strain relief.
Instead of the holding member 80 it is also possible to provide a plug connector.
Inasmuch as a tensile force acts on the flexible line 52 in a direction perpendicularly to the insertion direction, it is not received by the holding member 80 but by part 69 of the housing 22; compare line 52C in FIG. 9.
The part 69 stabilizes in the area of the corner 64 the two flange parts 26 and 28 relative to one another. This is advantageous when attaching the fan 20 by means of its flanges 26, 28, for example, in the case of a screw connection with screws passing through. In the area of the other corners analog reinforcements can be provided, as illustrated clearly in FIG. 1.
The invention is particularly advantageous in combination with a diagonal fan but can also be used in axial fans. Naturally, within the context of the invention several variations are possible. For example, the shortened stay or support 50 can also be of such a length that it is connected to the corner 64 of the fan housing 22, for which purpose a somewhat different shape than that of the stays 46 must be provided. Also, the invention can be used in the same way where lines are used which are relatively rigid, i.e., no litz wires, for connecting a fan. These and other modifications are within the scope of the invention.
While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
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Number | Date | Country | |
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20040096325 A1 | May 2004 | US |