JP2011214470A - Fan motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fan motor solving a defect that when some sort of strong shock or vibration is added to the fan motor, force of a rotating shaft tending to slip out toward an opening exceeds force (locking strength) preventing the rotating shaft from slipping out of a locking member, an engagement part of the locking member elastically deforms and the rotating shaft slips out from the locking member.SOLUTION: The locking member 7 includes an extension 7b extending radially from a base 7a of the locking member 7. The extension 7b includes engagement portions 7c engaging with a small-diameter groove portion 4a and angular portions 7d projecting from the extension 7b toward the opening 2c and abutting on an abutment portion 6 provided radially outside.

Description

  The present invention relates to a cooling fan motor for CPUs and MPUs of small electric devices such as notebook computers.

  2. Description of the Related Art Conventionally, some fan motors include a rotary shaft retaining member. According to the fan motor of Document 1, the retaining member has a smaller inner diameter than the outer diameter of the rotating shaft and larger than the outer diameter of the small-diameter groove portion of the rotating shaft, and is provided on the inner diameter of the retaining member. In some cases, the joint portion is configured to engage with the small-diameter groove portion.

Japanese Patent Laid-Open No. 2002-242882

  However, the fan motor retaining member disclosed in Document 1 includes a hole into which the rotating shaft is inserted and an engaging portion that extends toward the center of the hole, and rotates the engaging portion to expand. In order to insert the shaft into the hole, it is formed by a flexible member. When a strong impact or vibration is applied to the fan motor, the force that the rotational shaft tries to come out toward the opening exceeds the force that prevents the rotational shaft from coming off from the retaining member (prevention strength). There is an inconvenience that the engaging portion of the stopper member is elastically deformed and the rotating shaft is detached from the stopper member.

  The present invention has been made in order to solve the above-described problem, and the engaging portion of the retaining member is elastically deformed toward the opening when the corner portion of the retaining member contacts the contact portion. It is intended to provide a fan motor that prevents the problem that the rotating shaft comes off from the casing.

  In order to solve the above-described problems, a fan motor of the present invention includes a rotating shaft having blades at one end and a small-diameter groove, a retaining member that engages with the small-diameter groove and prevents the rotating shaft from being removed, and a rotating shaft. In the fan motor, the retaining member is provided with a bearing that pivotally supports the shaft in the radial direction of the rotating shaft, and a housing in which an opening portion that extends the rotating shaft is formed at one end of the cylindrical portion that holds the retaining member and the bearing. And an extending portion extending in the radial direction from the base of the retaining member, the extending portion engaging with the small-diameter groove portion, and projecting from the extending portion toward the opening and in the radial direction It has a corner | angular part contact | abutted to the contact part provided in the outer side, It is characterized by the above-mentioned. In this way, when the corner portion of the retaining member abuts against the abutting portion, the engaging portion cannot be elastically deformed toward the opening portion, and the rotating shaft can be reliably prevented from coming out of the casing.

  Further, the retaining member and the bearing are arranged so as to overlap each other in the rotation axis direction, and the contact portion is provided on the inner peripheral surface of the bearing. If it carries out like this, since the corner | angular part of a retaining member and the contact part of a bearing contact | abut, it can prevent that a rotating shaft comes off from a housing | casing with few parts.

  Further, two bearings are provided in the rotation axis direction, and a retaining member is disposed between the bearings. In this way, by supporting the tip end side of the small-diameter groove portion of the rotating shaft with the bearing, a space for storing the tip of the rotating shaft can be omitted, and the fan motor can be made thin in the direction of the rotating shaft.

  According to the present invention, when the corner portion of the retaining member abuts on the abutting portion, the engaging portion cannot be elastically deformed toward the opening portion, and the rotation shaft can be reliably prevented from being detached from the housing.

Central sectional view of the fan motor 1 according to the first embodiment. Sectional drawing of the principal part of the fan motor 1 of Example 1. FIG. The principal part disassembled perspective view of the fan motor 1 of Example 1. FIG. Perspective view of retaining member 7 Plan view of retaining member 7 Sectional view taken along line XX in FIG. (A) (b) Sectional drawing which showed the assembly procedure of the retaining member 7 and the rotating shaft 4 (C) (d) Sectional drawing which showed the assembly procedure of the retaining member 7 and the rotating shaft 4 Cross section of spacer 14 Sectional drawing of the principal part of the fan motor 1 of Example 2. FIG. The principal part disassembled perspective view of the fan motor 1 of Example 2. FIG.

  Example 1 of the present invention will be described below with reference to the accompanying drawings with respect to a preferred embodiment of the present invention. 1 is a central sectional view of a fan motor 1 having a retaining member 7 for a rotating shaft 4 according to a first embodiment, FIG. 2 is a sectional view of a main part of the fan motor 1 according to the first embodiment, and FIG. 1 is an exploded perspective view of one fan motor 1. FIG.

In FIG. 1, a casing 2 made of a resin material is injection molded. The casing 2 is formed with a cylindrical tube portion 2a. The tube portion 2a has a bottom portion 2b at one end and an opening portion 2c at the other end.
A bearing 5 that supports the rotary shaft 4 in the radial direction is press-fitted and fixed to the cylindrical portion 2a.

  On the other hand, the stator 9 formed by winding the coil 11 on the circuit board 12 is fixed to the housing 2 by a method including adhesion around the cylindrical portion 2a, and is attached to the rotor 8 by a hall element (not shown). The magnetic change of the fixed multi-pole magnetized annular magnet 10 is detected, and the coil 11 is energized based on the detection result, thereby generating a rotating magnetic field and attracting the rotor 8 for rotational driving. A so-called brushless motor is constructed.

  The rotor 8 is integrally formed by insert-molding a rotating shaft 4 made of, for example, a stainless steel member rotatably supported by a bearing 5 and a plurality of blades 3.

  A plurality of air intake holes are formed in the fan motor 1, and air holes that communicate with each other are formed at the bottom of the housing 2 that holds the bearing 5 in a press-fitted state. And the rotating shaft 4 in which the blade | wing 3 was insert-molded rotates, and it is made to send air outside via an air hole.

  The bearing 5 is, for example, an oil-impregnated sintered metal bearing 5. The oil-impregnated sintered metal bearing 5 is obtained by impregnating a predetermined sintered oil in a porous sintered metal. Furthermore, the bearing 5 in the present embodiment is provided with two bearings 5 on the bottom 2b side and two bearings 5 on the opening 2c side along the rotation shaft 4. A notch (chamfering) is provided on the inner periphery of one end of each bearing 5 that abuts against the retaining member 7 disposed between the two bearings 5. The notch of the bearing 5 on the opening 2 c side is a contact portion 6 that contacts a corner portion 7 d (described later) of the retaining member 7.

  A retaining member 7 made of a resin material that is elastically deformable while maintaining the rotating shaft 4 in a retaining state is disposed between the two bearings 5. The resin material of the retaining member 7 is polyoxymethylene (polyacetal resin) or the like.

  On the other hand, the rotary shaft 4 has a convex tip surface having a predetermined curvature in which the tip of the rotary shaft 4 abuts against a thrust washer (not shown), and an outer diameter surface portion continuously formed from the tip surface and having a maximum diameter. The small diameter groove portion 4a having a small diameter from the outer diameter surface portion is formed by a processing method including lathe processing, and the retaining member 7 is configured to be positioned in the small diameter groove portion 4a and completed.

  In addition, a thrust washer (not shown) made of nylon or Teflon (registered trademark) with lubricity is disposed at the tip of the rotating shaft 4 that keeps the rotating shaft 4 in a retaining state. The thrust load of the shaft 4 is supported by a thrust washer, and the radial load of the rotating shaft 4 is supported by a bearing 5.

  In this embodiment, the order in which the casing 2 is housed in the cylindrical portion 2a is first a thrust washer (not shown), the bearing 5 on the bottom 2b side, the retaining member 7, the bearing 5 on the opening 2c side, and Finally, the rotating shaft 4 is inserted into the retaining member 7. The retaining member 7 is accommodated in the cylindrical portion 2a so that the corner portion 7d protrudes toward the opening portion 2c.

  4 is a perspective view of the retaining member 7, FIG. 5 is a plan view of a surface on which the corner portion 7d of the retaining member 7 is provided, and FIG. 6 is an XX arrow that is the center line of FIG. FIG. The retaining member 7 includes a ring-shaped base portion 7a having a hole in the center, and an extending portion 7b extending from the inner peripheral surface side of the base portion 7a toward the center of the base portion 7a. The extending portion 7 b includes an engaging portion 7 c that engages with the small-diameter groove portion 4 a of the rotating shaft 4, and a corner portion 7 d that is provided on the base portion 7 a side and contacts the abutting portion 6. The inner diameter dimension formed at the end surface of the extending portion 7b of the retaining member 7 is larger than the diameter dimension of the small-diameter groove portion 4a of the rotating shaft 4 and smaller than the outer diameter surface portion of the rotating shaft 4 in the free state. It is set. On the other hand, the outer diameter of the retaining member 7 is substantially the same as that of the cylindrical portion 2a. Further, the four extended portions 7b extend from the inner peripheral surface side of the base portion 7a toward the center, the engaging portions 7c are provided on the center sides of the respective extended portions 7b, and the base portions 7a of the respective extended portions 7b. A corner 7d is provided on the side.

  In FIG. 6, the corner portion 7 d protrudes from the extending portion 7 b in the direction of the rotation axis 4, and a cross section cut in the direction of the rotation axis 4 has a substantially right triangle shape. The inclined surface having a substantially right triangle shape faces the base portion 7a, and the inclined surface contacts a notch provided on the inner peripheral surface of the bearing 5 on the opening 2c side. The engaging portion 7c has a substantially trapezoidal cross section cut in the direction of the rotation axis 4, and has a slope inclined toward the center of the retaining member 7 on the side where the corner portion 7d is provided. The surface opposite to the slope of the engaging portion 7c is orthogonal to the direction of the rotation axis 4.

  FIGS. 7A, 7B, 8C, and 8D are cross-sectional views showing a procedure for assembling the retaining member 7 and the rotating shaft 4. FIG.

  First, in FIG. 7A, when the tip of the rotating shaft 4 is inserted into the bearing 5 from the opening 2c (A1), the tip of the rotating shaft 4 first hits the slope of the engaging portion 7c, but the base 7a. Since the extending portion 7b is formed toward the center of the retaining member 7 and the retaining member 7 is formed of an elastically deformable resin, an excessive amount of force is not required and insertion of the rotary shaft 4 is not necessary. The operator can do it with his fingertips. Further, the engaging portion 7 c has a slope, and when the slope is pressed by the rotating shaft 4, the engaging portion 7 c is easily elastically deformed, so that the rotating shaft 4 can be easily inserted into the retaining member 7.

  In FIG. 7B, by inserting the rotating shaft 4 toward the bottom 2b, the engaging portion 7c is elastically deformed with the base portion 7a as a fulcrum, and the tip of the rotating shaft 4 passes through the engaging portion 7c. Here, the reason why the engaging portion 7c can be elastically deformed is that the inner peripheral surface of the end portion that comes into contact with the retaining member 7 of the bearing 5 on the bottom portion 2b side is notched.

  FIG. 8C shows a state in which the assembly of the retaining member 7 and the rotating shaft 4 is finished. This state can be a non-contact and completely free state without mechanical interference of the retaining member 7 with respect to the rotating shaft 4.

  In FIG. 8D, when a force is applied to the rotating shaft 4 so as to be pulled out from the housing 2 toward the opening 2c (A2), the small-diameter groove portion 4a of the rotating shaft 4 first collides with the engaging portion 7c. The corner portion 7d hits the contact portion 6 by being pushed by the portion 7c. Since the corner portion 7d and the contact portion 6 are in contact with each other, the engaging portion 7c is not easily deformed, so that the rotating shaft 4 can be prevented from being detached from the housing 2. And the surface orthogonal to the rotating shaft 4 direction of the engaging part 7c exhibits the effect that the rotating shaft 4 is hard to come off with respect to the housing | casing 2 because of the shape. In this way, after the fan motor 1 is completed, the movement of the extending portion 7b is restricted, and the rotating shaft 4 is prevented from being detached from the housing 2. Therefore, the retaining of the rotating shaft 4 is ensured.

  A spacer 14 as shown in FIG. 9 may be provided between the bearing 5 on the opening 2 c side and the retaining member 7. The spacer 14 has a ring shape as a whole and has a hole in the center. When a cross section of the spacer 14 cut in the direction of the rotation axis 4 is viewed, a cutout (chamfer) that forms an inclined surface is formed on the inner peripheral surface of the spacer 14. The notch is an abutting portion 6, and the abutting portion 7 c makes it difficult for the engaging portion 7 c to be deformed, so that the rotating shaft 4 cannot be removed from the housing 2. In this way, after the fan motor 1 is completed, the movement of the extending portion 7b is restricted, and the rotating shaft 4 is prevented from being detached from the housing 2. Therefore, the retaining of the rotating shaft 4 is ensured. That is, it is possible to use the bearing 5 having no notch (chamfering) having the same shape as the corner portion 7d.

  A second embodiment which is another embodiment will be described. FIG. 10 is a cross-sectional view of a main part of the fan motor 1 according to the second embodiment, and FIG. 11 is an exploded perspective view of the fan motor 1 according to the second embodiment. In FIG.10 and FIG.11, about the same component as Example 1, the same code | symbol is attached | subjected and description is omitted.

  Although the number of the bearings 5 ′ in FIG. 10 is one, the length is approximately the same as the length of the two bearings 5 of the first embodiment stacked in the direction of the rotating shaft 4. The position of the retaining member 7 of the second embodiment having one bearing 5 'is different from that of the first embodiment. The retaining member 7 of the second embodiment is located at the bottom 2b of the cylindrical portion 2a, and the bottom 2b of the cylindrical portion 2a has a space 13 in which the tip of the rotating shaft 4 is accommodated. This space 13 is for the engaging portion 7c to be elastically deformed when the rotating shaft 4 passes through the retaining member 7. As in the first embodiment, the end of the bearing 5 ′ that contacts the retaining member 7 is in contact with the corner 7d on the inner periphery of one end of the bearing 5 ′ that contacts the retaining member 7. Provide a notch (chamfer). The configuration is the same as that of the first embodiment except for the points described above.

  In FIG. 11, in the present embodiment, the order of housing in the cylindrical portion 2 a of the housing 2 is such that the thrust washer (not shown), the retaining member 7, the bearing 5 ′, and finally the rotating shaft 4 are removed. Insert into the stop member 7. The retaining member 7 is accommodated in the cylindrical portion 2a so that the corner portion 7d protrudes toward the opening portion 2c. Needless to say, the spacer 14 may be used.

  The present invention is not limited to the above embodiment. The shape of the engaging portion 7c is not limited as long as it contacts the small diameter groove portion 4a of the rotating shaft 4.

  Further, although the extended portion 7b is formed at four positions toward the center of the retaining member 7, the rotating portion 4 is in contact with the abutting portion 6 to prevent the engaging portion 7c from elastically deforming. As long as it does not come out of the body 2, the number of the extending portions 7b is not limited.

  Further, the shape of the corner portion 7d is not limited as long as it is in contact with the contact portion 6 and prevents the engaging portion 7c from being elastically deformed and the rotating shaft 4 does not come out of the housing 2.

DESCRIPTION OF SYMBOLS 1 Fan motor 2 Case 2a Tube part 2b Bottom part 2c Opening part 3 Blade | wing 4 Rotating shaft 4a Small diameter groove part 5 Bearing 5 'Bearing 6 Contact part
7 Stopping member 7a Base portion 7b Extension portion 7c Engagement portion 7d Corner portion 8 Rotor 9 Stator 10 Magnet 11 Coil 12 Circuit board 13 Space 14 Spacer A1 Insertion direction A2 of rotation shaft 4 Extraction direction of rotation shaft 4

Claims (3)

A rotary shaft provided with a blade at one end and having a small-diameter groove portion, a retaining member that engages with the small-diameter groove portion to prevent the rotational shaft from being removed, and a bearing that supports the rotational shaft in the radial direction of the rotational shaft And a fan motor comprising a housing formed with an opening through which the rotating shaft extends at one end of a cylindrical portion that holds the retaining member and the bearing.
The retaining member has an extending portion extending in the radial direction from a base portion of the retaining member,
The extending portion includes an engaging portion that engages with the small-diameter groove portion, and a corner portion that protrudes from the extending portion toward the opening portion and contacts an abutting portion provided on the radially outer side. A fan motor comprising: The retaining member and the bearing are arranged so as to overlap in the rotation axis direction,
The fan motor according to claim 1, wherein the contact portion is provided on an inner peripheral surface of the bearing.   3. The fan motor according to claim 1, wherein two bearings are provided in the direction of the rotation axis, and the retaining member is disposed between the bearings.

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