Fan noise-lowering structure

A fan noise-lowering structure includes a fan frame and a connection section. The fan frame has a bottom side and a circumferential wall. The circumferential wall defines an airflow passage. Two ends of the airflow passage respectively have an inlet and an outlet. The connection section is disposed on inner side or outer side of the circumferential wall. The connection section has an internal passage. Two ends of the internal passage respectively have an inlet end and an outlet end. The outlet end is disposed on the inner side of the circumferential wall in connection with the airflow passage near the inlet. The inlet end is disposed on the bottom side in flush with the outlet. The connection section serves to guide the high-pressure air at the outlet to jet to the inlet so as to achieve multiple noise-lowering effects.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a fan noise-lowering structure, and more particularly to a fan noise-lowering structure including a connection section. The connection section serves to guide the high-pressure airflow produced at the outlet of the fan to jet to the inlet so as to achieve multiple noise-lowering effects.

2. Description of the Related Art

The noise made by the fan is always one of the problems existing in the field of fans to be improved. The conventional technical means for solving the fan noise problem is to use a circuit to control the rotational speed or change the fan structure. A prior art discloses a technique in which an airflow jet is disposed on the dynamic blades or the frame wall of the static blades to restrain the vortex. However, it is necessary to add an external connected airflow jet source to the fan. This cannot be achieved in a limited space. In addition, the extra external connected airflow jet source will lead to increase of the cost.

It is therefore tried by the applicant to provide a fan noise-lowering structure, which can lower the noise of the fan without using additional equipment.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide a fan noise-lowering structure, in which a self-airflow jet noise-lowering structure is disposed on the fan frame to solve he fan noise problem.

To achieve the above and other objects, the fan noise-lowering structure of the present invention includes a fan frame and a connection section.

The fan frame has a bottom side and a circumferential wall. The circumferential wall is normal to the bottom side and annularly disposed on one face of the bottom side. The circumferential wall defines an airflow passage. Two ends of the airflow passage respectively have an inlet and an outlet. The connection section is disposed on inner side or outer side of the circumferential wall. The connection section has an internal passage. Two ends of the internal passage respectively have an inlet end and an outlet end. The outlet end is disposed on the inner side of the circumferential wall in connection with the airflow passage near the inlet. The inlet end is disposed on the bottom side in flush with the outlet. The connection section serves to guide the high-pressure air at the outlet to jet to the inlet so as to achieve multiple noise-lowering effects.

Still to achieve the above and other objects, the fan noise-lowering structure of the present invention includes a first fan, a second fan and a connection section.

The first fan has a first bottom side and a first circumferential wall. The first circumferential wall is normal to the first bottom side and annularly disposed on one face of the first bottom side. The first circumferential wall defines a first airflow passage. Two ends of the first airflow passage respectively have a first inlet and a first outlet.

The second fan has a second bottom side and a second circumferential wall. The second circumferential wall is normal to the second bottom side and annularly disposed on one face of the second bottom side. The second circumferential wall defines a second airflow passage. Two ends of the second airflow passage respectively have a second inlet and a second outlet. The first and second fans are vertically assembled with each other.

The connection section is disposed on inner sides or outer sides of the first and second circumferential walls. The connection section has an internal passage. The internal passage has a first inlet end, a first outlet end, a second inlet end and a second outlet end. The first inlet end is connected with the second outlet end. The first outlet end is disposed on the inner side of the first circumferential wall in connection with the first airflow passage near the first inlet. The second inlet end is disposed on the second bottom side of the second fan in flush with the second outlet.

By means of the self-airflow jet structure of the present invention, the airflow with higher pressure at the outlet of the fan is guided to jet to the inlet of the fan so as to lower the noise of the entire fan.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer toFIG. 1, which is a sectional view of a first embodiment of the fan noise-lowering structure of the present invention. As show in the drawing, the fan noise-lowering structure1of the present invention includes a fan frame11and a connection section12.

The fan frame11has a bottom side111and a circumferential wall112. The circumferential wall112is normal to the bottom side111and annularly disposed on one face of the bottom side111. The circumferential wall112defines an airflow passage113. Two ends of the airflow passage113respectively have an inlet1131and an outlet1132. The outlet1132is positioned at one end of the airflow passage113near the bottom side111. The inlet1131is positioned at the other end of the airflow passage113opposite to the outlet1132.

The connection section12is disposed on inner side or outer side of the circumferential wall112. In this embodiment, the connection section12is disposed on the inner side of the circumferential wall112for illustration purposes. The connection section12has an internal passage121. Two ends of the internal passage121respectively have an inlet end122and an outlet end123. The inlet end122is disposed on the bottom side111in flush with the outlet1132of the fan frame11. The outlet end123is disposed on the inner side of the circumferential wall112in connection with the airflow passage113near the inlet1131.

The bottom side111has a bearing cup113perpendicularly extending from the bottom side111.

Please now refer toFIG. 2, which is a sectional view of a second embodiment of the fan noise-lowering structure of the present invention. The second embodiment is partially identical to the first embodiment in structure and thus will not be redundantly described hereinafter. The second embodiment is different from the first embodiment in that the connection section12is disposed on the outer side of the circumferential wall112on four corners of the fan frame11.

Please now refer toFIG. 3, which is a sectional view of a third embodiment of the fan noise-lowering structure of the present invention. According to the third embodiment, the fan noise-lowering structure2of the present invention includes a first fan21, a second fan22and a connection section23.

The first fan frame21has a first bottom side211and a first circumferential wall212. The first circumferential wall212is normal to the first bottom side211and annularly disposed on one face of the first bottom side211. The first circumferential wall212defines a first airflow passage213. Two ends of the first airflow passage213respectively have a first inlet2131and a first outlet2132.

The second fan frame22has a second bottom side221and a second circumferential wall222. The second circumferential wall222is normal to the second bottom side221and annularly disposed on one face of the second bottom side221. The second circumferential wall222defines a second airflow passage223. Two ends of the second airflow passage223respectively have a second inlet2231and a second outlet2232. The first and second fans21,21are vertically serially connected and assembled with each other. The first outlet2132is mated with the second inlet2231.

The connection section23has an internal passage231. The internal passage231has a first inlet end2311, a first outlet end2312, a second inlet end2313and a second outlet end2314. The first inlet end2311is connected with the second outlet end2314. The first outlet end2312is disposed on the inner side of the first circumferential wall212in connection with the first airflow passage213near the first inlet2131. The second inlet end2313is disposed on the second bottom side221of the second fan22in flush with the second outlet2232.

The second inlet end2314of the internal passage231of the connection section23serves to guide the higher-pressure airflow to jet from the second outlet2232of the second fan22to the first inlet2131of the first fan21so as to lower the noise.

The first bottom side211has a first bearing cup2111perpendicularly extending from the first bottom side211. The second bottom side221has a second bearing cup2211perpendicularly extending from the second bottom side221.

The first outlet2132is positioned at one end of the first airflow passage213near the first bottom side211. The first inlet2131is positioned at the other end of the first airflow passage213opposite to the first outlet2132. The first inlet end2311is adjacent to the first outlet2132. The first outlet end2312is adjacent to the first inlet2131.

The second outlet2232is positioned at one end of the second airflow passage223near the second bottom side221. The second inlet2231is positioned at the other end of the second airflow passage223opposite to the second outlet2232.

Please now refer toFIG. 4, which is a sectional view of a fourth embodiment of the fan noise-lowering structure of the present invention. The fourth embodiment is partially identical to the third embodiment in structure and thus will not be redundantly described hereinafter. The fourth embodiment is different from the third embodiment in that the connection section23is disposed on the outer sides of the first and second circumferential walls212,222on four corners of the first and second fans21,22.

In the present invention, the airflow of the high-pressure section (the outlet) of the fan is jetted to the low-pressure section (the inlet) of the fan so as to lower the noise of the fan.

In the present invention, the inlet end of the connection section is disposed on the bottom side of the fan frame in flush with the outlet. Accordingly, when the outlet of the fan is full of the airflow, the excessive airflow can be poured from the inlet end of the connection section into the internal passage of the connection section. The airflow is then exhausted from the outlet end of the connection section to jet to the inlet of the fan frame so as to lower the noise of the fan.

The connection section can be disposed in the wall of the fan frame itself or externally added to the fan frame. This is not limited.

The present invention has been described with the above embodiments thereof and it is understood that many changes and modifications in such as the form or layout pattern or practicing step of the above embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.