GB2542842A

GB2542842A - Self-cooling loudspeaker

Info

Publication number: GB2542842A
Application number: GB1517369.3A
Authority: GB
Inventors: Alejandro Lopez Castillo Jorge
Original assignee: Tymphany Hong Kong Ltd
Current assignee: Tymphany Hong Kong Ltd
Priority date: 2015-10-01
Filing date: 2015-10-01
Publication date: 2017-04-05
Anticipated expiration: 2035-10-01
Also published as: GB201517369D0; GB2542842B

Abstract

A self-cooling loudspeaker comprises a frame 31, 32, a diaphragm portion 22 connected to the frame via a surround 40, an elastic suspension spider 50 member connected to the frame, a voice coil 60 connected to the diaphragm portion and a magnet assembly 70 connected to the frame. First and second airflow control members 80, 90 are disposed for regulating air flows generated by the loudspeaker during sound reproduction. The first and second airflow control members regulate the amount of cool air flowing into the loudspeaker and hot air flowing out by way of passages 33, 74 which lie between regions S1, S2, s3 and S4.

Description

SELF-COOLING LOUDSPEAKER FIELD OF THE INVENTION

[0001] The present invention relates to speaker structure and more particularly, to a self-cooling loudspeaker, which has airflow control members and air passages for airflows.

BACKGROUND OF THE INVENTION

[0002] When a loudspeaker works for reproducing a sound via a voice coil built therein, the voice coil becomes the source of the heat in the loudspeaker. The voice coil heats up as the electric current flows through. Part of the heat generated by the voice coil is transferred to the air and other members of the loudspeaker around the voice coil. Materials of which the members of the loudspeaker are made exhibit a poor thermal conductivity, e.g. the magnetic members of the loudspeaker. As the heat transferred to these members, the heat is not effectively liberated but it is rather stored in these members over time.

[0003] The heat stored in these members of the loudspeaker increases the temperature of the loudspeaker. The high temperature handled by the loudspeaker during the sound reproduction may cause critical issues, such as high power compression, demagnetization of the magnet members, and moreover it can damage some of the members of the loudspeaker leading to a severe loudspeaker failure.

[0004] A solution for this problem is equipping the loudspeaker with some extra pieces made of materials with good thermal conductivity, such as aluminium, in strategic places and with specific shapes so that the efficiency of the loudspeaker dissipating heat increases. These pieces are so called heat sinks.

[0005] Heat sinks help dissipate heat, however, in some circumstances this is not enough and the heat released by the heat sinks into the adjacent air needs also to be moved, so that the temperature in the loudspeaker can be dropped more.

[0006] Apart from choosing materials which can handle high temperature, another conventional solution that helps the loudspeaker to achieve a good power handing is to pierce the structure of the loudspeaker at specific areas so that the hot air can be released from cavities of the loudspeaker. However, the expelled hot air stays in the surroundings of the loudspeaker. The hot air that was removed may come back into the loudspeaker again without a proper control of the airflows.

SUMMARY OF THE INVENTION

[0007] It is therefore an object of the invention to provide a self-cooling loudspeaker which can control airflows and the paths the airflows flow in such that only air from cool regions flows into the loudspeaker while hot air remains outside of the loudspeaker.

[0008] In order to achieve the object, the invention provides a loudspeaker being capable of self-cooling as well as reproducing sound. The loudspeaker comprises a frame, a diaphragm portion connected to the frame via a surround, an elastic member connected to the frame, a voice coil connected to the diaphragm portion, a magnet assembly connected to the frame, and first and second airflow control members disposed in the loudspeaker for regulating air flows produced during the process of sound reproduction. In particular, there is provided a self-cooling loudspeaker comprising: a frame; an elastic member connected to the frame; a diaphragm portion connected to the frame, the diaphragm portion being capable of linear movement, wherein a space inside the loudspeaker substantially surrounded by the frame, the elastic member and the diaphragm portion defines a first region located towards the front of the loudspeaker; a voice coil connected to the diaphragm portion; a magnet assembly connected to the frame at the back of the loudspeaker, the magnet assembly having a central opening and a first air passage into which the voice coil is disposed, wherein a space inside the loudspeaker substantially surrounded by the voice coil, the elastic member and the frame defines a second region, wherein a space inside the loudspeaker substantially surrounded by the magnet assembly and the diaphragm portion defines a third region, and a fourth region is defined at the back of the loudspeaker on the opposite side of the magnet assembly to the third region; a first airflow control member connected to the frame and in fluid communication with the first region and the second region, wherein the linear movement of the diaphragm portion produces an airflow and the direction of the airflow is regulated by the first airflow control member from the first region to the second region; and a second airflow control member connected to the central opening of the magnet assembly, wherein the linear movement of the diaphragm portion produces an airflow and the direction of the airflow is regulated by the second airflow control member from the third region to the fourth region.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a section view of a self-cooling loudspeaker in accordance with an embodiment of the invention. FIG. 2 is a section view of the self-cooling loudspeaker showing air flows as a diaphragm portion of the loudspeaker makes an upward movement in accordance with an embodiment of the invention. FIG. 3 is a section view of the self-cooling loudspeaker showing air flows as a diaphragm portion of the loudspeaker makes a downward movement in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In order to fully comprehend the objectives, features and efficacy of the present invention, a detailed description of embodiments of the invention is given below, by way of example only, in conjunction with the accompanying drawings. The description is as below.

[0011] Referring to FIG. 1, this is a section view of a self-cooling loudspeaker 1 in accordance with the embodiment of the invention. The loudspeaker 1 comprises a frame 30, a diaphragm portion 20 connected to the frame 30 via (in this embodiment) both a surround 40 located at the front of the loudspeaker and an elastic member 50 located rearward of the surround 40 towards the back of the loudspeaker, a voice coil 60 connected to the diaphragm portion 20 via a coil former 61, a magnet assembly 70 connected to the frame 30 and located at the back of the loudspeaker, and first and second airflow control members 80, 90 disposed therein for regulating airflows. The surround 40 is optional.

[0012] The frame BO of the loudspeaker 1 as a cartridge may be constructed of a stiff anti-vibrational material, e.g. steel: baskets and frames are commonly made of steel or cast aluminum or plastic. The frame includes a first basket 31 and a second basket 32. The first basket 31 is disposed towards the front of the loudspeaker and the second basket 32 abuts the first basket and is disposed towards the back of the loudspeaker. The first basket and the second basket are connected to each other and provide the external surface of the frame. The first basket and the second basket are preferably substantially annular in shape. The second basket is provided with at least one internal second air passage 33 that follows the contour of the wall of the second basket 32 in cross-section. The second air passage 33 is disposed between the intersection of the first and second baskets 31, 32 and the magnet assembly 70. The first air flow control member 80 is disposed at the distal end of the second air passage 33, which end is adjacent the first basket 31 and is located towards the front of the loudspeaker. The proximal end of the second air passage 33 (the end located towards the back of the loudspeaker) is located adjacent the front face of the magnetic assembly (ie the face facing the front of the loudspeaker). In the present embodiment, two second air passages are present in the wall of the second basket and two first airflow control members are used, one for each air passage.

[0013] The diaphragm portion 20 includes a dome 21 which is adjacent to a cone 22. The dome, also called a dust-cup 21, and cone 22 together form the diaphragm portion 20. The dome is substantially spherical with its apex located towards the front of the loudspeaker. The cone is truncated and has its widest circular end located towards the front of the loudspeaker. The dome is located inside the cone towards or adjacent the narrowest circular end of the cone. The circular base of the dome preferably has a greater diameter than the diameter of the narrowest circular end of the cone. The dome 21 and cone 22 can be made by well damped materials such as silk or paper. At the edge of the cone 22, at its widest circular end, the diaphragm portion 20 is connected to the frame 30 by the surround 40, which may be made from a flexible and fatigue resistant material such as a rubber. The frame 30 of the loudspeaker 1 is also connected to the diaphragm portion 20 by the elastic member 50, one end of which is connected to the frame adjacent the first airflow control member 80. The other end of the elastic member 50 is connected to the diaphragm portion and/or the coil former 61 and may be connected to the frame 30 by the coil former 61. Conventionally, the elastic member 50 is called as spider. In such a manner, the surround 40 and the elastic member 50 can limit the diaphragm portion 20 to a linear movement relative to the frame 30 of the loudspeaker 1. The linear movement in FIG. 1 is an upward and backward motion for reproducing sound for a user of the loudspeaker 1. Furthermore, the internal space of the loudspeaker surrounded by the cone 22 of the diaphragm portion 20, the first basket 31, the surround 40 and the elastic member 50 is a first region SI of the loudspeaker 1.

[0014] A coil former 61 is connected to the diaphragm portion 20 adjacent the intersection of the cone 22 and dome 21. The elastic member 50 may be connected to the diaphragm portion and/or the coil former at this point adjacent to the intersection. The voice coil 60 is attached to the coil former 61. The space under the elastic member 50 and surrounded by the elastic member 50, the second basket 32, the coil former 61, and the voice coil 60 is a second region S2 of the loudspeaker 1. Also, the second air passage 33 is in the second region S2.

[0015] The magnet assembly 70 of the loudspeaker 1 comprises a substantially annular top plate 71, a magnet 72, and a substantially annular yoke portion 73 with an approximately U-shaped profile. The magnet 72 is a substantially annular member having a central opening. The magnet is disposed between a lower (back) face of the top plate 71 and an upper (front) face of the yoke portion 73. The top plate and the yoke portion also have central openings which are substantially aligned with the central opening of the magnet. The yoke portion 73 defines a space for the voice coil 60 to be disposed therein and forms a first air passage 34 which intercommunicates with the second region S2 and a third region S3 which is a space located between the underside of the dome 21 of the diaphragm portion 20 and the upper (front) face of the top plate 71 of the magnet assembly 70. In the present embodiment, a substantially central space defines the third region whilst substantially annular spaces define each of the first and second regions. The second region may substantially surround the third region.

[0016] The second airflow control member 90 is disposed in the central opening of the magnet assembly 70. At the back of the loudspeaker, under the second airflow control member 90 and the lower (back) face of the yoke portion 73 of the magnet assemble 70 is a space defined as a fourth region S4.

[0017] In the embodiment, the first and second airflow control members 80, 90 are one-way air valves for regulating the transference of air during sound reproduction from the first region SI to the fourth region S4. That is, the first airflow control member 80 only allows a flow of air from the first region SI to the second region S2 via the second air passage 33. The second airflow control member 90 only allows a flow of air from the third region S3 to the fourth region S4 via the central hole of the magnet assembly 70. The airflow control members are adapted to fit snugly at the entrance of or within the relevant aperture to ensure good control of airflow. The proximal end of the second air passage 33 (the end located towards the back of the loudspeaker) is located adjacent one end of the first air passage 34, this end of the first air passage being in the second region S2.

[0018] Referring to FIG. 2 and FIG. 3, during the sound reproduction, as the diaphragm portion 20 performs the linear movement (respectively shown by the arrow), the air molecules around the diaphragm portion 20 are pushed back and forth. Therefore, the loudspeaker 1 produces airflows in response to these movements. Besides, during the sound reproduction the voice coil 60 becomes the source of heat in the loudspeaker 1. The voice coil 60 heats up as an electric current flows through, and part of the heat is transferred to the air and the elements near the voice coil 60. Therefore, the temperatures of air in the second region S2, the third region S3 and the fourth region S4 are higher than the temperature of air in the first region SI. Also, the temperature in region S4 can be almost the same as that in region S3 since region S4 is in direct contact with the motor assembly as well.

[0019] During the upward movement of the loudspeaker 1 as shown in Fig. 2, the cooler air from the first region SI is pumped into the second air passage 33 to the second region S2 (illustrated by the arrows) where the voice coil 60 is disposed therein, and then air flows through the first air passage 34 to the third region S3. Therefore, the heat produced by the voice coil 60 can be liberated. The cooler air from the first region SI guided by the second air passage 33 which follows the contour of the second basket 32 of the frame 30, can avoid interfering with or modifying any other elements of the loudspeaker 1. During the upward movement of the loudspeaker 1, the first airflow control member 80 allows air molecules in the first region SI to flow into the second air passage 33 since the air molecules experience a suction effect and are sucked into the second region S2 and the third region S3. Air molecules in the fourth region S4 also experience a suction force into the third region S3, however, the second airflow control member 90 blocks the access since the second airflow control member 90 only allows the air to flow out of the loudspeaker 1.

[0020] In a similar method, during the downward movement of the loudspeaker 1 as shown in Fig. 3, hotter air from the second and third regions S2, S3 is pushed out of the loudspeaker 1 into the fourth region S4 (illustrated by the arrows) via the second airflow control member 90 through the central hole 74 of the magnet assembly 70 which is also a venting hole of the loudspeaker 1. Because the second airflow control member 90 only allows air out of the loudspeaker 1, hotter air stays out of the loudspeaker 1. Moreover, the airflow that is released through the second airflow control member 90 assists to carry away the hot air molecules at the fourth region S4. There is also some air pushed back into the second air passage 33. But the second air passage 33 is contained by the first airflow control member 80 which remains closed for airflows that head out of the loudspeaker 1. In this way, hot air from the second and third regions S2, S3 does not exit where the cooler air is taken from.

[0021] Although two first airflow control members and one second airflow control member are used in the embodiment, one skilled in the art can select the number and type of airflow control members depending, for example, on the size of the loudspeaker and how much and how efficiently the airflows are wanted to be controlled.

[0022] The present invention is disclosed by the preferred embodiment in the aforementioned description; however, it is contemplated for one skilled at the art that the embodiments are applied only for an illustration of the present invention rather than are interpreted as a limitation for the scope of the present invention. It should be noted that the various substantial alternate or replacement equivalents to these embodiments shall be considered as being covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the claims.

Claims

1. A self-cooling loudspeaker comprising: a frame; an elastic member connected to the frame; a diaphragm portion connected to the frame, the diaphragm portion being capable of linear movement, wherein a space inside the loudspeaker substantially surrounded by the frame, the elastic member and the diaphragm portion defines a first region located towards the front of the loudspeaker; a voice coil connected to the diaphragm portion; a magnet assembly connected to the frame at the back of the loudspeaker, the magnet assembly having a central opening and a first air passage into which the voice coil is disposed, wherein a space inside the loudspeaker substantially surrounded by the voice coil, the elastic member and the frame defines a second region, wherein a space inside the loudspeaker substantially surrounded by the magnet assembly and the diaphragm portion defines a third region, and a fourth region is defined at the back of the loudspeaker on the opposite side of the magnet assembly to the third region; a first airflow control member connected to the frame and in fluid communication with the first region and the second region, wherein the linear movement of the diaphragm portion produces an airflow and the direction of the airflow is regulated by the first airflow control member from the first region to the second region; and a second airflow control member connected to the central opening of the magnet assembly, wherein the linear movement of the diaphragm portion produces an airflow and the direction of the airflow is regulated by the second airflow control member from the third region to the fourth region.

2. The self-cooling loudspeaker as claimed in claim 1, wherein the first and second airflow control members are one-way air valves.

3. The self-cooling loudspeaker as claimed in claim 1 or claim 2, wherein the first air passage connects the second region and the third region.

4. The self-cooling loudspeaker as claimed in any preceding claim, wherein the central opening of the magnet assembly is the venting hole of the loudspeaker and the second airflow control member is connected thereto and is preferably disposed therein.

5. The self-cooling loudspeaker as claimed in any preceding claim, the frame further comprising a first basket and a second basket, the first region being surrounded by the first basket, the diaphragm portion, and the elastic member, and the second region being surrounded by the second basket, the elastic member, and the voice coil, wherein the second basket is provided with at least one internal second air passage that follows the contour of the second basket.

6. The self-cooling loudspeaker as claimed in claim 5, wherein the second air passage is in the second region.

7. The self-cooling loudspeaker as claimed in claim 5 or claim 6, wherein one end of the second air passage is connected to the first air control member, and the other end of the second air passage is adjacent to the first air passage.

8. The self-cooling loudspeaker as claimed in claim 7, the magnet assembly further comprising a top plate, and wherein the end of the second air passage which is adjacent to the first air passage is adjacent the top plate of the magnet assembly.

9. The self-cooling loudspeaker as claimed in any preceding claim, further comprising a surround which connects the diaphragm portion and the frame at or towards the front of the loudspeaker.

10. The self-cooling loudspeaker as claimed in any preceding claim, wherein a substantially central space defines the third region.

11. The self-cooling loudspeaker as claimed in any preceding claim, wherein a substantially annular space defines the first region.

12. The self-cooling loudspeaker as claimed in any preceding claim, wherein a substantially annular space defines the second region.

13. A self-cooling loudspeaker substantially as hereinbefore described with reference to the accompanying diagrammatic drawings.