JP6182292B2 - Blower - Google Patents

Description

The present invention relates to a blower having a hub which is rotated by a motor.

  A conventional blower is configured by housing a stator and a rotor constituting a motor in a case, and fixing an impeller to a shaft that has come out of the case (Patent Document 1). The impeller is composed of a hub and a blade member attached to the hub.

  As shown in FIG. 4 of Patent Document 1, the hub is configured in a cup shape from a cylindrical side portion that covers the side surface of the motor and a bottom portion that closes one opening of the side portion. The hub is fixed to the motor shaft at the center of the bottom.

  Further, as a configuration of the hub, there is conventionally known a configuration in which a hole is provided in the bottom portion of the hub in order to send heat of the motor to the outside (Patent Documents 2 and 3).

JP 2001-304189 A JP 2012-154270 A JP 2012-246806 A

  Conventionally, when a blower is used to cool, for example, a spindle motor of a machine tool, oil such as machine oil, cutting fluid, and oil mist may adhere to the blower depending on the environment in which it is used.

  In such a use environment, if oil remains in the hub and the oil adheres to the shaft exposed between the hub and the motor case, the operation of the motor may be affected.

  Patent Documents 2 and 3 disclose hubs having holes in the bottom plate, but these holes are provided to release heat to the outside. If a large hole is provided in the hub in order to effectively discharge the liquid such as oil or water from the hub in an environment where mist-like oil or water is used, the rigidity of the hub may be impaired.

Then, an object of this invention is to provide the air blower provided with the hub which has the function and rigidity which discharge | emit liquids, such as oil and water.

The present invention for solving the above problems, and an impeller motor and Ru fixed to the shaft of the motor, and a vane impeller rotates with the hub and the hub, the hub, the contour circle with plate A blower comprising: a formed circular portion; and a cylindrical portion in which an edge of one opening is formed integrally with a peripheral edge of the circular portion, wherein the circular portion has a central portion and a central portion via a stepped portion. , And an outer peripheral portion disposed so as to be shifted from the center portion to the outside of the hub. The central portion includes a through hole through which the shaft passes , and the outer peripheral portion includes a plurality of convex portions formed so as to bulge outward from the front surface of the circular portion around the through hole. A portion of the surface on the back side of the circular portion corresponding to the convex portion is formed as a recess recessed from the inside of the hub to the outside of the hub. The projecting part has a hole that leads from the inside of the hub to the outside of the hub , the motor case has a ring-like projecting part on the surface facing the circular part, and the projecting part is located at a position close to the step part, making it complicated Labyrinth that forms a simple passage is constructed.

  The convex portion of the hub is desirably formed so that the height from the front surface of the circular portion increases as it goes from the through hole of the circular portion toward the periphery.

  The convex part of the hub includes, for example, an arc-shaped first side part centering on the through hole, and a second side part and a third side formed from both ends of the first side part toward the peripheral side of the circular part. A fourth side portion that is formed in an arc shape centering on the through hole and connects the end of the second side portion and the end of the third side portion, the first side portion, the second side portion, and the third side portion And a ceiling portion that closes a region surrounded by the fourth side portion. It is desirable that the distance between the second side portion and the third side portion is formed so as to increase as it goes from the through hole of the circular portion toward the periphery. More preferably, the hole is formed in a part of a corner region formed by the ceiling portion and the fourth side portion.

The present invention for solving the above problems, and an impeller that is fixed to the motor Toko motor shaft, and a blade rotating with the hub Toko hub blade roots vehicle equipped with a plurality of convex portions, the hub A circular portion having a plate-like outline and a cylindrical portion in which the edge of one opening is formed integrally with the peripheral edge of the circular portion and the other opening faces upward, and the circular portion is liquid It is a blower provided with the reservoir part which accumulates. The circular portion includes a central portion, and an outer peripheral portion that is provided around the central portion via a stepped portion and that is displaced from the central portion to the outside of the hub. The central portion penetrates the shaft through the center. The outer peripheral portion includes a plurality of convex portions formed so as to bulge outward from the front surface of the circular portion around the through hole. The portion of the surface on the back side of the circular portion corresponding to the convex portion is formed as a recess recessed from the inside of the hub to the outside of the hub to form a reservoir, and the convex portion has a hole that leads from the inside of the hub to the outside. .

Further motor case, the surface facing the circular section, have a ring-like projection is disposed at a position where collision detection section is close to the step portion, the labyrinth forming the complex passageways have been configured The

  According to the present invention, the liquid in the hub can be discharged to the outside while ensuring the rigidity of the hub.

It is a perspective view of a hub concerning an embodiment of the present invention. It is a front view of the hub concerning the embodiment of the present invention. It is a rear view of the hub which concerns on embodiment of this invention. It is a side view of the hub concerning the embodiment of the present invention. (A) is an end view of the hub along the line aa in FIG. 2, (B) is an end view of the hub along the line bb in FIG. 2, and (C) is a line cc in FIG. FIG. 6 is an end view of the hub along. It is a fragmentary perspective view of the hub concerning the embodiment of the present invention. (A) is a perspective view of the propeller blower of 1st Example of this invention, (B) is a disassembled perspective view of a propeller blower. (A)-(C) are the front view, side view, and rear view of the propeller fan of 1st Example of this invention. It is sectional drawing of the propeller air blower along the dd line of FIG. 8 (A). It is a perspective view which shows the radial blower of 2nd Example of this invention. (A)-(C) are the front view of the radial blower of 2nd Example of this invention, a side view, and a rear view. It is sectional drawing of the radial blower along the ee line of FIG. 11 (A).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is a perspective view of a hub 1 according to an embodiment of the present invention, FIG. 2 is a front view of the hub 1, FIG. 3 is a rear view of the hub 1, FIG. 4 is a side view of the hub 1, and FIGS. C) is an end view of the hub 1 along the lines aa, bb and cc of FIG.

  The hub 1 is composed of a circular portion 10 formed in a plate shape having a circular outline, and a cylindrical portion 20 in which the edge of one opening is connected to the peripheral edge of the circular portion 10. The circular portion 10 and the cylindrical portion 20 are connected by a corner portion 30, and in the illustrated example, the surface of the corner portion 30 is formed as a curved surface. The circular portion 10, the cylindrical portion 20, and the corner portion 30 are integrally formed.

  As shown in FIG. 5C, the circular portion 10 includes a central portion 11 that occupies a circular region from the center to a predetermined distance, and a ring-shaped outer peripheral portion that occupies a region to the periphery of the circular portion 10 around it. 12. The outer peripheral portion 12 is connected to the central portion 11 through the step portion 13.

  The outer peripheral portion 12 is arranged on the outer side of the hub so as to be separated from the central portion 11 from the inner side of the hub toward the outer side of the hub when the axis of the cylindrical portion 20 is represented by a one-dot chain line X in FIG. As a result, the flat surface S1 of the central portion 11 and the flat surface S2 of the outer peripheral portion 12 are arranged with their positions shifted in the axis X direction.

  The central portion 11 includes a through hole 14 through which a tip portion of a shaft of a motor described later passes.

  The outer peripheral portion 12 includes a plurality of convex portions 15. FIG. 6 is a partial perspective view of the hub, and particularly shows the convex portion 15 in an enlarged manner. As shown in this figure, the convex portion 15 is formed so that the surface on the front side of the circular portion 10 swells to the outside of the hub.

  In the illustrated example, the convex portion 15 includes four side portions (hereinafter referred to as a first side portion 15A, a second side portion 15B, a third side portion 15C, and a fourth side portion 15D, respectively) connected to the frame mold, A ceiling portion 15E that covers an area surrounded by the four first side portions 15A to the fourth side portion 15D. The four first side portions 15A to the fourth side portion 15D protrude from the surface of the outer peripheral portion 12 to the outside of the hub.

  The first side portion 15A and the fourth side portion 15D are formed in an arc shape along a circle formed by the stepped portion 13 and the peripheral edge of the circular portion 10. The second side portion 15B and the third side portion 15C are linearly formed from the through hole side of the circular portion 10 toward the peripheral side.

  The second side portion 15B and the third side portion 15C are formed such that the height from the surface of the outer peripheral portion 12 gradually increases from the through hole side toward the peripheral edge side of the circular portion 10. The convex part 15 is formed higher on the peripheral side of the circular part 10 than on the through hole 14 side. Furthermore, the distance between the second side portion 15B and the third side portion 15C increases from the through hole side toward the peripheral edge side of the circular portion 10. The width of the convex portion 15 is formed wider on the peripheral side of the circular portion 10 than on the through hole 14 side.

  The peripheral edge of the ceiling part 15E is formed integrally with the four first side parts 15A to the fourth side part 15D, and in each edge part constituting the peripheral edge of the ceiling part 15E, the edge part arranged on the through hole side and a circular shape The edge portion disposed on the peripheral side of the portion 10 is formed in an arc shape following the shape of the first side portion 15A and the fourth side portion 15D, and the remaining edge portions are linear so as to connect both ends thereof. Is formed. The outline of the ceiling portion 15E is formed in a trapezoidal shape.

  The ceiling portion 15E is formed as a sloped surface S3 as shown in FIG. 5A when the flat surface S2 of the outer peripheral portion 12 shown in FIG. 5C is used as a reference. The surface S3 has a gradient that gradually increases from the surface S2 of the outer peripheral portion 12 from the through hole side toward the peripheral edge side of the circular portion 10, that is, increases. The corner C (see FIG. 5A) formed by the ceiling 15E and the fourth side 15D is formed to be the highest.

  Since the convex portion 15 is composed of the four first side portions 15A to 15D and the ceiling portion 15E, the portion corresponding to the convex portion 15 on the back surface of the circular portion 10 is shown in FIG. As shown to 5 (A), it forms as the hollow 16 dented outside the hub.

  The convex portion 15 has a hole 18 that leads from the inside of the hub to the outside of the hub at the position of the corner portion C, in other words, at the deepest position in the recess formed in the back surface of the circular portion 10. As shown in FIGS. 2 and 6, the hole 18 is formed as an arc-shaped slit along the fourth side portion 15 </ b> D. Further, the hole 18 is formed only in an intermediate region excluding both end portions in the length direction of the fourth side portion 15D.

  In the present embodiment, the angle of the arc formed by the fourth side portion 15D is set to 60 degrees, and the angle of the arc formed by the hole 18 is set to 25 degrees. Shorter than full length. Further, in the present embodiment, one convex portion 15 is provided in a region of 30 degrees with the through hole 14 as a center, and the six convex portions 15 are arranged in a region of 180 degrees that is half of the entire circumference of the circular portion. Yes.

  As shown in FIGS. 2 and 3, the convex portions 15 formed in this way are arranged at equiangular intervals on the outer peripheral portion 11 of the circular portion 10 with the through hole 14 as the center.

  From the position adjacent to the stepped portion 13 of the outer peripheral portion 12 to the position near the outer peripheral edge of the outer peripheral portion 12, for example, the radial direction of the circular portion 10 is used as the reference for each of the convex portions 15 in the present embodiment. The dimensions are set so as to occupy about 60% to 90% of the area.

  Although the details of the embodiment will be described later, the hub 1 configured as described above is used as a member that is attached to a shaft of a motor and rotates together with blades and the like.

At the time of use, for example, it is used in a posture in which Up in FIGS. 5A and 5B is vertically upward and the other opening of the cylindrical portion 20 of the hub 1 , that is, the opened mouth portion 21 is directed upward. In this usage example, each convex portion 15 protrudes from the inner side of the hub toward the outer side of the hub. Therefore, the region inside the convex portion 15 stores a liquid such as oil or water (hereinafter referred to as a reservoir portion). Available as

  In addition, since each convex portion 15 is formed so that the width gradually increases from the through hole side toward the peripheral side of the circular portion 10, a large amount of oil is accumulated, and these are stored in the hub 1 from the hole 18. It can be discharged outside.

  Since the depth of each convex portion 15 is formed so as to gradually increase from the through hole side toward the peripheral edge side of the circular portion 10, liquid such as oil or water can be separated from the shaft side. Furthermore, since each convex part 15 as the depression 16 is provided with the hole 18 at the deepest part, it is possible to prevent oil or liquid from staying in the reservoir part.

  As described above, according to the hub 1 according to the present embodiment, even when a liquid such as water or oil enters the hub, the liquid such as water or oil can be effectively discharged.

  Further, in the example shown in FIGS. 5A and 5B, the central portion 11 connected to the shaft is different in height from the outer peripheral portion 12 having a discharging function, and the central portion 11 is higher than the outing portion 12. Therefore, since the liquid such as oil or water is separated from the bottom in the hub, that is, the convex portion 15 as the depression 16, it can be expected to suppress the influence of the liquid adhering to the shaft and solidifying.

  Thus, according to hub 1 concerning this embodiment, even if liquids, such as water and oil, permeate in a hub, contact to the shaft of a motor can be controlled effectively.

  Moreover, since the hole 18 is provided in the most protruding part of each convex part 15, it can also suppress that liquids, such as oil and water, permeate into the hub from the hole 18.

  Furthermore, in each convex part, since the hole part 18 for extracting liquids, such as oil and water, was provided only in a part of each convex part, the discharge function is ensured effectively while ensuring the rigidity of the hub. be able to.

[First embodiment]
FIG. 7A is a perspective view of the propeller blower 100 according to the first embodiment of the present invention, and FIG. 7B is an exploded perspective view of the propeller blower 100. 8A is a front view of the propeller blower 100, FIG. 8B is a side view of the propeller blower 100, and FIG. 8C is a rear view of the propeller blower 100. FIG. 9 is a cross-sectional view of the propeller blower 100 taken along the line dd in FIG.

  The propeller blower 100 includes a motor 50 and a first impeller 110 fixed to the shaft 53 of the motor 50.

  As shown in FIG. 9, the motor 50 includes a stator 51, a rotor 52, a shaft 53 that rotates together with the rotor 52, and a first bearing 54 and a second bearing 55 that rotatably support both ends of the shaft 53. And a case 56 for housing them.

  The case 56 includes a base 561 and a cover 562 covering the base 561. In the region surrounded by the base 561 and the cover 562, that is, in the case, the stator 51, the first bearing 54, and the second bearing 55 are fixed. The stator 51 is provided with windings, which may be sealed with resin. In the region inside the stator 51, the rotor 52 is rotatably arranged. The rotor 52 is fixed to the shaft 53 with the shaft 53 passing through the center. A portion of the shaft 53 that appears outside the rotor 52 is supported by a first bearing 54 and a second bearing 55.

  As shown in FIG. 7B, the cover 562 is provided facing the base 561 and has a circular ceiling portion 562A that covers the top of the stator 51 and the rotor 52, and a cylindrical side portion 562B that covers the side surface of the stator 51. And is formed in a cup shape.

  The ceiling portion 562A has a through hole 562C in the center. With the cover 562 covering the stator 51 and the like, the tip of the shaft 53 protrudes outside the cover 562.

  In addition, on the surface of the ceiling portion 562A, a protruding portion 562D is formed in a circular shape centering on the through hole 562C of the cover 562.

  The first impeller 110 includes the hub 1 and a plurality of blades 120 attached to the cylindrical portion 20 of the hub 1.

  The hub 1 is fixed to the tip of the shaft 53 protruding from the through hole 562C of the motor 50. As shown in FIG. 9, a washer 57 and a bearing collar 58 are disposed between the hub 1 and the second bearing 55. The hub 1 is mounted on a bearing collar 58 (FIG. 7B) partially protruding out of the motor 50 case from the through hole 562 </ b> C of the motor 50 and the shaft 53 protruding from the through hole 14 of the hub 1. It is fastened to the motor 50 by fastening with a nut 61 via a collar 59 and a spring washer 60 at the tip. Reference numeral 70 in FIGS. 7 and 9 denotes a lead wire connected to the winding, and FIG. 8 represents the motor 50 with the lead wire 70 omitted.

  The propeller blower 100 configured as described above includes the hub 1 of the present embodiment, so that liquid such as oil and water in the hub can be discharged out of the blower while securing the rigidity of the hub 1. it can.

Further, with the hub 1 attached to the motor 50, the protruding portion 562 </ b> D of the ceiling portion 562 </ b> A of the motor 50 constitutes the labyrinth 80 together with the circular portion 10 of the hub 1. With the hub 1 attached to the motor 50, the stepped portion 13 that forms the boundary between the central portion 11 and the outer peripheral portion 12 is disposed at a position closer to the shaft 53 than the protruding portion 562D. A space V between the ceiling portion 562A and the ceiling portion 562A is configured as a labyrinth 80 that forms a complex passage as it approaches the shaft 53 as shown in FIG. The labyrinth 80 can also suppress the adhesion of liquid such as oil and water to the shaft 53.

[Second Embodiment]
FIG. 10 is a perspective view showing a radial blower 200 according to the second embodiment of the present invention. 11A is a front view of the radial blower 200, FIG. 11B is a side view of the radial blower 200, and FIG. 11C is a rear view of the radial blower 200. FIG. 12 is a cross-sectional view of the radial blower 200 taken along line ee in FIG.

  The radial blower 200 includes a motor 50 and a second impeller 210 fixed to the shaft 53 of the motor 50. Since the configuration of the motor 50 is the same as that of the first embodiment, the description thereof is omitted. 10 and 11, the lead wire 70 is omitted and the motor 50 is shown.

  The second impeller 210 includes the hub 1 and a blade member 220 attached to the hub 1.

  The blade member 220 includes a first annular member 230, a second annular member 240 that is provided apart from the first annular member 230, and a space between the first annular member 230 and the second annular member 240. And a plurality of blades 250 provided in.

  As shown in FIG. 12, the first annular member 230 has a cylindrical mounting portion 231 and the axial direction of the mounting portion 231 from one opening edge of the mounting portion 231 (the rotational axis direction of the shaft 53 in FIG. 12). And an annular blade support portion 232 extending in a direction orthogonal to the direction.

  The blade support portion 232 is provided with a plurality of openings used when fixing the blade 250. As shown in FIG. 11B, the second annular member 240 is formed to have the same outer dimensions as the first annular member 230, but the circle constituting the inner peripheral edge (FIG. 12) is a blade support portion. The radius is set larger than the radius of the inner periphery of H.232.

  As shown in FIG. 12, the second annular member 240 is formed as a curved surface having a roundness from the inner peripheral edge to the outer peripheral edge on the rotating shaft side. The second annular member 240 is provided with a plurality of openings used when the blades 250 are attached.

  The blades 250 are configured, for example, as rectangular plate pieces. The claws 251 are inserted into the opening of the first annular member 230 and bent at the upper edge, and the blades 250 are inserted into the opening of the second annular member 240 at the lower edge and bent. Claw 252. 10 and 11 show a state in which the claws 251 and 252 are bent.

  In the impeller 210, as shown in FIG. 12, the attachment portion 231 of the first annular member 230 is fixed to the cylindrical portion 20 of the hub 1. As a fixing method, for example, the cylindrical portion 20 of the hub 1 is press-fitted into a cylindrical shape constituting the mounting portion 231, and the cylindrical surface of the mounting portion 231 and the outer peripheral surface of the cylindrical portion 20 of the hub 1 are bonded with an adhesive. The blade member 220 is fixed to the hub 1 by joining.

  The hub 1, the first annular member 230, the second annular member 240, and the plurality of blades 250 constituting the impeller 210 are made of, for example, an aluminum alloy or a cold-rolled steel plate.

  Since the radial blower 200 configured as described above includes the hub 1 of the present embodiment, liquid such as oil and water in the hub can be discharged out of the blower while securing the rigidity of the hub 1. it can.

[how to use]
The usage method and effect | action of the propeller air blower 100 of this Example comprised as mentioned above and the radial air blower 200 are demonstrated.
The motor 50 is mounted with the base 561 on the upper side and the circular portion 10 of the hub 1 on the lower side, for example, for cooling the spindle of a machine tool . When attaching to the machine tool , the flange of the base 561 is fixed to the machine tool with a screw or the like.

When the blower is used, for example, when mist oil from a machine tool adheres to the impellers 110 and 210, the oil is scattered to the outside of the blower by the centrifugal force generated by the rotation of the impellers 110 and 210. Further, when oil from the machine tool traces the side of the case 561 of the base 561 or the motor 50 and enters the hub, the oil is accumulated in the reservoir, and is formed at the bottom of the reservoir by the centrifugal force generated by the rotation of the blower. Oil can be discharged from the hole 18. Note that oil can be discharged from the hole 18 even when the blower is stopped. By preventing oil from entering the motor 50 in this way, it can be expected that the motor 50 will be used for a long time.

As described above, the use of the blower of the present invention is not limited to cooling a motor of a machine tool . Further, the impeller and its component parts may be made of resin. The usage method is not limited to a posture in which the shaft of the motor extends vertically upward or a posture in which the mouth portion 21 of the hub 1 faces vertically upward.

  The configuration of the blower is not limited to the above description. For example, the blower may be configured as an axial blower provided with a frame or a guide plate around the propeller blower.

  The number, shape, size, and arrangement position of the convex portions provided in the circular portion are not limited to the illustrated example. For example, the outline of the ceiling part is formed into a quadrangle, a triangle, etc., the angle of inclination is an angle other than that shown in the figure, the plane is parallel to the surface S2, and the arrangement intervals of the plurality of convex parts are arranged at equal angles. Or other forms. The length and angle of the arc formed by the first side portion 15A, the fourth side portion 15D, and the hole 18 are not limited to the above description.

  The circular part provided with the convex part may be configured without the step part. The dimensions of the members such as the blade 120 and the blade member 220 are not limited to the illustrated example, and the size, shape, number, position, orientation, and the like of the blade are not limited.

  The fixing method of the hub is not limited to the above description, and instead of the nut for fixing the hub to the motor, for example, a cylindrical boss and a screw having a screw hole on the side surface may be used. The boss is fixed in the through hole of the hub. The screw is attached to the boss with the motor shaft passing through the boss, and the shaft is fixed at the tip of the screw protruding into the boss.

DESCRIPTION OF SYMBOLS 1 Hub 10 Circular part 11 Center part 12 Outer peripheral part 13 Step part 14 Through-hole 15 Convex part 15A 1st side part 15B 2nd side part 15C 3rd side part 15D 4th side part 15E Ceiling part 16 Depression 18 Hole 20 Cylinder part 21 mouth part 30 corner part 50 motor 51 stator 52 rotor 53 shaft 54 first bearing 55 second bearing 56 case 561 base 562 cover 562A ceiling part 562B side part 562C through hole 562D protrusion 57 washer 58 bearing collar 59 color 60 Spring washer 61 Nut 70 Lead wire 80 Labyrinth 100 Propeller fan 110 First impeller 120 Blade 200 Radial fan 210 Second impeller 220 Blade member 230 First annular member 231 Mounting portion 232 Blade support portion 240 Second annular Member 2 50 blades 251,252 nails

Claims (6)

A motor and an impeller fixed to the shaft of the motor;
The impeller includes a hub and a blade that rotates together with the hub,
The hub is a blower comprising a plate-like circular portion having a circular outline and a cylindrical portion in which the edge of one opening is formed integrally with the peripheral edge of the circular portion,
The circular portion includes a central portion, and an outer peripheral portion that is provided around the central portion via a stepped portion and is displaced from the central portion to the outside of the hub,
It said central portion is provided with a through hole through which the shaft in the center, the outer peripheral portion has a plurality of convex portions formed so as inflated to the hub outside the front surface of the circular portion around the through hole ,
The portion of the surface on the back side of the circular portion corresponding to the convex portion is formed as a recess recessed from the inside of the hub to the outside of the hub,
The convex portion has a hole that leads from the inside of the hub to the outside of the hub,
The motor case has a ring-shaped protrusion on the surface facing the circular portion,
The protrusion is disposed at a position close to the step portion, characterized in that the labyrinth which forms a complex path is configured, the blower. A motor and an impeller fixed to the shaft of the motor;
The impeller includes a hub and a blade that rotates together with the hub,
The hub includes a plate-like circular portion having a circular outline, and a cylindrical portion in which an edge of one opening is formed integrally with a peripheral edge of the circular portion, and the other opening faces upward.
Further, the circular portion is a blower provided with a reservoir for storing liquid ,
The circular portion includes a central portion, and an outer peripheral portion that is provided around the central portion via a stepped portion and is displaced from the central portion to the outside of the hub,
The central portion includes a through hole through which the shaft passes, and the outer peripheral portion includes a plurality of convex portions formed so as to bulge outward from the front surface of the circular portion around the through hole. ,
The part of the back side surface of the circular part corresponding to the convex part is formed as a recess recessed from the inside of the hub to the outside of the hub, and constitutes the reservoir part,
The convex portion has a hole that leads from the inside of the hub to the outside of the hub,
The motor case has a ring-shaped protrusion on the surface facing the circular portion,
The blower characterized in that a labyrinth that forms a complex passage is configured by arranging the protruding portion in a position close to the stepped portion. The convex portion is characterized by peripheral side of the through hole side of the circular portion is formed such that the height increases from the front surface of the circular portion of claim 1 or 2 Blower . The convex portion includes an arc-shaped first side portion centering on the through hole, and a second side portion and a third side formed from both ends of the first side portion toward the peripheral side of the circular portion. A first side part, a second side part, a fourth side part formed in an arc shape centered on the through hole and connecting the end of the second side part and the end of the third side part , a ceiling portion for closing the region surrounded by the third side and the fourth side is composed of,
Distance between the second side and the third side is characterized in that the formed such circular peripheral edge side of the through-hole side of widens, to any one of claims 1 to 3 The blower described . The blower according to claim 4, wherein the hole is formed in a part of a corner region formed by the ceiling portion and the fourth side portion. Wherein the other opening of the cylindrical portion is fitted et al is to the machine tool in a posture facing upward, blower according to any one of claims 1 to 5.

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