Heat dissipation fan

[0002] 1. Field of the Invention

[0003] The present invention relates to a heat dissipation fan, and more particularly to a heat dissipation fan that has a lubricating bearing with an oil guide to prolong the life of the heat dissipation fan.

[0004] 2. Description of Related Art

[0005] With reference to FIG. 5, a conventional heat dissipation fan in accordance with the prior art comprises a casing (30) and a fan (32) rotatably mounted in the casing (30). A stator (34) with an electromagnet formed in the stator (34) is securely fixed in the casing (30). A permanent magnet (322) is mounted in the fan (32) to be a rotor, such that the fan (32) can rotate due to the interaction between the magnetic forces in stator (34) and the permanent magnet (322). A sleeve (38) is securely mounted on a base (302) formed in the casing (30) and pressed into the stator (34). A lubricating bearing (36) with lubrication oil contained therein is pressed into the sleeve (38). A shaft (324) extends from the fan (32) and through the bearing (36). A locking disk (50) is mounted on the free end of the shaft (324) to securely hold the bearing (36) on the shaft (324) so the fan (32) can rotate relative to the casing (30) with very little friction. Because the lubrication oil will flow out of the bearing (36) when the fan (32) is in operation, a seal (42) and a gasket (40) must be mounted on the shaft (324) at each end of said lubricating bearing (36) to keep the lubrication oil from leaking out of the sleeve (38) and drying out the bearing (36).

[0006] However, during the assemble of the conventional heat dissipation fan, the sleeve (38) must first be pressed into the casing (30) base (302). Then the casing (30) must be turned over to install the circuit board (35) and stator (34) in the casing (30) and the lubricating bearing (36) into the sleeve (38) with a specific hand tool. After mounting the seal (42) and the gasket (40) on the shaft (324), the shaft (324) extends through the central hole of the bearing (36). The casing (30) must be turned over again to install the second seal (46), gasket (44) and the locking disk (50) on the free end of the shaft (324) with a specific hand tool. Finally, a cover (39) is mounted on the base (302) of the casing (30) to close the base (302). Consequently, the assembly of the conventional heat dissipation fan is very difficult and tedious. In addition, because the heat dissipation fan usually works with a small object like the CPU of a computer, the volume of the heat dissipation fan must be small, and the components of the heat dissipation fan are very tiny. This will further increase the difficulty and tedium of assembling the conventional heat dissipation fan. Furthermore, the conventional heat dissipation fan does not have any oil guilds, so the lubrication oil easily flows out of the sleeve (38). Consequently, the bearing will easily dry out, and the useful life of the heat dissipation fan will be decreased.

[0007] To overcome the shortcomings, the present invention tends to provide an improved heat dissipation fan to mitigate or obviate the aforementioned problems.

[0008] The main objective of the invention is to provide an improved heat dissipation fan having a casing, a circuit board, a stator, a sleeve, a lubricating bearing, a fan, a shaft and a locking disk. The lubricating bearing contained lubrication oil. The fan is rotatably mounted in the casing. The shaft extends from the fan and through the lubricating bearing. A locking disk is securely mounted on the free end of the shaft. has a central hole is defined in the lubricating bearing. A chamber is defined in the bottom end of the bearing, and at least one oil groove is longitudinally defined in the outer periphery of the bearing. The oil groove provides a guide to the lubrication oil to keep the oil from flowing out of the sleeve.

[0009] Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

[0010] FIG. 1 is an exploded perspective view of a heat dissipation fan in accordance with the present invention;

[0011] FIG. 2 is a side plan view in partial section of the heat dissipation fan in FIG. 1;

[0012] FIG. 3 is an exploded side plan view of the heat dissipation fan in FIG. 1 showing the assembly operation;

[0013] FIG. 4 is a side plan view in partial section of the heat dissipation fan in FIG. 1 showing the direction of the lubrication oil flow; and

[0014] FIG. 5 is a side plan view in partial section of a conventional heat dissipation fan in accordance with the prior art.

[0015] With reference to FIGS. 1 and 2, a heat dissipation fan in accordance with the present invention comprises a casing (10) and a fan (12) with multiple blades (122) arranged on the outer periphery rotatably mounted in the casing (10). A chamber (102) is defined in the casing (10) to receive the fan (12). A stator (14) is securely mounted in the chamber (102) of the casing (10). A permanent magnet (13) mounted in the fan (12) to be the rotor. A sleeve (18) is pressed into the stator (14) and is securely mounted in the casing (10) by pressing the central hole (182) of the sleeve (18) onto a protrusion (104) integrally formed at the center of the inside face of the casing (10) chamber (102).

[0016] A lubricating bearing (16) with lubrication oil contained therein is securely mounted in the sleeve (18). A central hole (162) is defined in the lubricating bearing (16). A chamber (164) communicating with the central hole (162) is defined in the bottom end of the lubricating bearing (16). At least one oil groove (166) is longitudinally defined in the outer periphery of the lubricating bearing (16).

[0017] An inclined flange (184) extends toward the central hole (182) from the top end of the sleeve (18) and abuts the top end of the lubricating bearing (16), such that an annular space is defined between the top end of the bearing (16) and the sleeve (18) flange (184). At least one recess (186) is defined in the free end of the flange (184). In addition, a cone portion (124) is formed on the fan (12) and abuts the inclined flange (184) of the sleeve (18). An annular groove (125) is defined in the cone portion (124) and faces the central hole (182) of the sleeve (18).

[0018] A shaft (126) extends from the cone portion (124) of the fan (12), into the sleeve (18) and through the central hole (162) of the lubricating bearing (16). A neck (127) is defined near the free end of the shaft (126), such that a head (128) is formed on the free end of the shaft (126). A locking disk (19) with a central hole (192) securely engages with the neck (127) in the shaft (126) to securely hold the bearing (16) on the shaft (124). The diameter of the central hole (192) of the locking disk (19) is smaller than the diameter of the shaft (124), and multiple slits (194) extend radially from the central hole (192) of the disk (19). By such an arrangement, when the head (128) of the shaft (126) extends into the central hole (192) of the locking disk (19), the central hole (192) will deform and enlarge for the shaft (126) to pass through the hole (192). When the head (128) of the shaft (126) passes through the central hole (192) of the locking disk (19), the central hole (192) of the disk (19) will rebound to its original configuration and be held in the neck (127) of the shaft (126). In addition, a recess (106) is defined in the protrusion (104) of the casing (10) to accommodate the head (128) of the shaft (126).

[0019] With reference to FIGS. 1-3, to assemble the heat dissipation fan the sleeve (18) is positioned in an assembly jig with the flange (184) downward, and the stator (14) and the circuit board (I 5) are sequentially pressed onto the outer periphery of the sleeve (18). The lubricating bearing (16) is pressed into the sleeve (18), and the locking disk (19) is put into the sleeve (18) to abut the lubricating bearing (16). Then the protrusion (104) in the casing (10) is pressed into the central hole (182) of the sleeve (18) and abuts the locking disk (19), such that the sleeve (18) with the stator (14), the circuit board (15), the lubricating bearing (16) and the locking disk (19) are securely mounted in the casing (10). Then the casing (10) is turned over, and the fan (12) shaft (126) is pushed into the sleeve (18). When the head (128) of the shaft (126) extends through the central hole (162) of the lubricating bearing (16), the shaft (126) will penetrate the locking disk (19) central hole (192) and be automatically locked into position. Because only one step requires turning the assembly over during the assembly of the heat dissipation fan, the manufacturing process is significantly simplified, and the cost and time of manufacturing the heat dissipation fan is decreased.

[0020] With reference to FIG. 4, the fan (12) and the shaft (126) in operation will rotate relative to the sleeve (18) due to the interaction of the stator (14) and the permanent magnet (13) in the fan (12). Because the shaft (126) extends through the lubricating bearing (16), the shaft (126) will rotate freely with very little friction. In addition, any lubrication oil that flows from the lubricating bearing when the heat dissipation fan is in operation will flow into the chamber (164) and the space between the bearing (16) and the sleeve (18) flange (184) through the recess (186) in the flange (184). The oil flowing into the space will recycle through the oil grooves (166). This keeps the lubrication oil from leaking out of the sleeve (18) and drying out the bearing (16). The oil flowing into the chamber (164) will be stored in the chamber (164) and the recess (106) of the protrusion (104), such that the oil can provide a lubricating effect to the shaft (126). This can further reduce the friction between the shaft (126) and the lubricating bearing (16) to avoid noise and wear. Therefore, the oil guide in the heat dissipation fan extends the useful life of the heat dissipation fan.

[0021] Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.