JPS60156999A - Fan fitting structure of motor fan - Google Patents

Abstract

PURPOSE:To eliminate eccentricity between a motor and a fan at the time of their fitting and reduce a vibration and also improve assembling workability and further prevent the fan from cracking by making a boss hole diameter smaller than that of a shaft, and providing a slit groove and further connecting the fan with a plate on the outer periphery of the shaft. CONSTITUTION:At the time of assembling a fan 14, since comparison between a boss hole diameter D and a shaft diameter (d) is D<=d, diameter expanding force works on the boss hole 16. This force is absorbed by deformation of slit grooves 17 as shown by imaginative lines in an illustration, and the boss hole 16 and a motor shaft 12, maintaining eccentricity due to symmetrical arrangement of said grooves, easily adapt themselves to deformation for fitting by a slight force. Further, since the fan 14 is fixed to a plate 13 in an outer peripheral position of the motor shaft 12, it performs transmission of rotation and prevents change in shape of the boss hole 16 by means of centrifugal force of rotation at the same time so that eccentricity can be maintained. Thus, eccentricity at the time of fitting a motor 11 and the fan 14 is eliminated, and vibration due to rotation can be reduced, and further improvement of assembling workability and prevention of the fan 14 from cracking can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a fan mounting structure for a motor fan, and particularly to a fan mounting structure suitable for directly connecting a resin molded fan to a motor shaft.

(b) Background of the technology A motor fan is a fan that is directly driven to rotate by a motor, and is installed in the engine compartment of an automobile. In such a motor fan, since the fan is directly connected to the motor shaft, there is a demand for reliable centering and good assembly mountability from the viewpoint of vibration prevention and assembly work.

(c) Prior art and problems Conventionally, as a structure for attaching a resin molded fan to a motor, for example, Utility Model Application Publication No. 58-114899 or Fig. 1-
There is something like the one shown in Figure 2.

This is done by fixing a plate 3 to the shaft 2 of the motor 1 by press-fitting or the like, and then fixing the boss part 5 of the fan 4 to the plate 3, which is molded with resin.
They are assembled by fitting the boss holes 6 provided in the shafts 2 and overlapping them, and screwing the nuts 7 onto the tips of the shafts 2 and tightening them. The plate 3 is press-fitted perpendicularly to the central axis of the motor shaft 2 to restrict vibration of the rotating surface of the fan 4. Further, a plurality of small holes 8 are bored along the circumference on the surface of the plate 3, and a pin 9 that fits into the small holes 8 is protruded from the inner surface of the boss portion 5.
driving force is transmitted.

However, in such a conventional fan assembly configuration, there are tolerances in the inner diameter D of the boss hole 6 and the diameter d of the motor shaft 2 due to manufacturing reasons.
If an eccentricity of d)/2 occurs and D≦d, assembly must be performed by press-fitting. For this reason, when eccentricity occurs, vibrations occur due to the rotation, which may cause the mount portion of the motor 1 to vibrate or damage the bearing portion that supports the motor shaft 2. In addition, when it is in the normal state, it becomes difficult to assemble it, and there are problems such as cracks occurring in the warp boss hole 6 where the pressing force is large.

B) Purpose of the Invention The present invention has been made by focusing on the above-mentioned conventional problems.
To provide a fan mounting structure for a motor 1 in which centering of a motor shaft and a fan is easy and there is no fear of cracking a boss hole.

B) Structure of the Invention In order to achieve the above object, the present invention provides a fan mounting structure for a motor fan in which a boss part of a resin fan is fitted and fixed onto a motor shaft, in which the diameter of the boss hole is set relative to the diameter d of the motor shaft. D≦d, a plurality of slit grooves are provided at equal intervals on the inner periphery of the boss hole, and the boss is connected to a plate fixed to the motor shaft at the outer periphery of the motor shaft, thereby solving the above problems. It is something.

(F) Embodiments of the Invention Below, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 3 and 4 show an embodiment of the present invention, and show an enlarged sectional view of the mounting portion and a front view of the boss hole. As shown, motor 1
A plate 13 having a plane orthogonal to the axis of the shaft is fixed to the shaft 12 by press fitting. Facing this play 1-13, a boss portion 15 of a fan 14 is attached by fitting the boss hole 16 from the tip of the shaft 12.

Here, the inner diameter of the boss hole 16 is set to be equal to or smaller than the outer diameter d of the motor shaft 12.
That is, they are formed in a Dad relationship. Therefore, when the fan 14 is installed, it will be press-fitted into the shaft 12, but in order to escape the press-fitting force, a pair of 180-degree opposing positions are provided on the inner peripheral edge of the boss hole 16, as shown in FIG. A slit groove 17 is provided. Slit groove 1
7 opens into the boss hole 16, and a cornered curved portion 18 is provided in the inner portion of the boss hole 16 to prevent stress concentration due to the notch effect.

Further, the inner surface of the boss portion 16 of the fan 14 fitted onto the motor shaft 12 is in a state of being joined to the plate 13, but the two are connected in order to properly transmit rotational torque. For this connection, a screw insertion hole I9 is formed on the circumference of the outer circumferential position of the motor shaft 12, and a screw hole 20 is formed in the plate 13 corresponding to the insertion hole 19. This is done by tightening a screw 21 that is screwed into a screw hole 20.

According to such an embodiment, when assembling the fan 14,
Since the boss hole diameter and the shaft diameter d satisfy D≦d, a diameter expanding force acts on the boss hole 16. However, this force is absorbed by the deformation of the slit groove 17 as shown by the imaginary line in Figure 4, and since the boss hole 16 and motor shaft 12 are arranged symmetrically, the concentricity between the boss hole 16 and the motor shaft 12 is maintained. It easily conforms to the force, deforms, and fits into place. Also, fan 14
is fixed to the plate 13 at the outer circumferential position of the motor shaft 12, so that the rotation is transmitted and, at the same time, the centrifugal force of the rotation prevents the shape of the boss hole 16 from changing and maintains concentricity. Furthermore, even if the slit groove 17 is deformed, the corner-trimmed curved portion 1
8, there is no stress concentration and undesirable deformation stress can be dispersed.

Figures 5 and 6 show modified examples of the boss hole.
The one in the figure shows an example in which slit grooves 17 are provided at three locations, and the one in FIG. 6 shows an example in which slit grooves 17 are provided at four locations. Both are arranged and formed at equal intervals, and the boss holes 16 maintain concentricity with the motor shaft 12 and are deformable.

Therefore, these embodiments can also function in the same way as the above embodiments.

According to each of these embodiments, since the diameter dimension only needs to be D≦d, the tolerance of the boss hole 16 of the fan 14 may be large, and the tightening of the fan 14 on the motor shaft 12 side is fixed. Therefore, there is an effect that the perpendicularity of the fan 14 to the shaft 12 by the plate 13 can be made more perfect.

0) Effects of the Invention As described above, according to the present invention, the diameter of the boss hole is made smaller than the diameter of the shaft, the slit groove is provided, and the structure is connected to the plate on the outer circumference of the shaft. It has the excellent effect of eliminating eccentricity during installation, reducing rotational vibration, improving assembly workability, and preventing cracks and cracks in the fan.

[Brief explanation of drawings]

FIG. 1 is a sectional side view of a main part of a conventional motor fan structure, FIG. 2 is an enlarged sectional view of the same main part, and FIG. FIG. 4 is a front view of the boss hole, and FIGS. 5 and 6 are front views showing modified examples of the boss hole. 1.11...Motor, 2,12...Motor shaft, 3,13...Plate, 4,14...Fan, 5
．． 15...Boss part, 6.16...Boss hole, 17...
・Slit groove, 20...screw hole, 21...screw. Patent applicant: Japan Radiator Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] Fan mounting for motor 1, in which the resin fan boss part is inserted into the motor shaft and fixed (in the -J structure, the boss hole diameter is formed so that D≦d with respect to the motor shaft diameter d,
A fan mounting structure for a motor fan, characterized in that a plurality of slit grooves are provided at equal intervals on the inner periphery of the boss hole, and the boss portion is connected to a plate fixed to the motor shaft at the outer periphery of the motor shaft.