JP2010013937A - Blower device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blower device which prevents the occurrence of run-out through the improvement of a mounting structure of a fan. <P>SOLUTION: In a blower device which is driven by an engine and rotates a fan through a flywheel, the fly wheel 31 and fan 11 are fixed onto a drive shaft 43 of the engine by a mounting member 42, at a tip end of the mounting part 42 a screw part 42d which passes though a mounting hole 45 of the fan 11 is formed to fix the fan 11 with a bolt 41, a polygonal part 42b is formed in the vicinity of an axially intermediate part of the mounting member 42, and an inner wall 35a abuttable on the polygonal part 42b in a rotating direction is formed at the rear end of the fan 11. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an improvement in a fan mounting method of a blower device used for a work for blowing fallen leaves, cut grass, and the like by rotating a fan with an engine and blowing out sucked air from a discharge port.

  Conventionally, as this type of blower apparatus, for example, in Patent Document 1, a structure in which a fan in the apparatus is rotated by driving an engine and air sucked from an intake port of the housing is ejected from an exhaust port of the housing is known. ing. A conventional blower apparatus and its usage will be described with reference to FIGS. The blower device 101 driven by driving means such as a two-cycle or four-cycle engine has a pipe 119 and a nozzle 118 attached to the exhaust port of the fan, and the nozzle 118 is blown while holding the blower device 101 by holding the handle portion 107. They are blown by wind pressure toward the fallen leaves and cut grass that are the object 100.

  Further, as shown in FIG. 14, the blower device 101 has a vacuum pipe 155, an extension pipe 156, and a suction pipe 157 attached to the suction port side, and a dust collecting bag 159 attached to the discharge port side via a vent pipe 158, A method of sucking cut grass and collecting it in the dust collecting bag 159 is also possible.

JP 2001-140800 A

  Generally, in a blower device, a fan is fixed to an engine via a flywheel. However, if this fixing method is not sufficient, the fan may run out or vibrate during rotation. Therefore, various ideas have been made to fix the flywheel so that the runout does not occur.

  FIG. 11 is a perspective view showing the shape of a fan 111 according to the prior art, and FIG. 12 is a cross-sectional view showing a mounting structure of the fan 111. As shown in FIG. In FIG. 11, a fan 111 is a so-called centrifugal fan, which guides air sucked in the axial direction outward in the radial direction and discharges it in the circumferential direction. For this purpose, a plurality of fins 139 extending in the radial direction are formed. A flat circular region 175 is formed on the inner peripheral side of the fan 111, and screw holes 176 for fixing the fan 111 are formed at two locations near the outer periphery of this region.

  In FIG. 12, the flywheel 131 is fixed to the crankshaft 143 of the engine by bolting. Two screw hole inlets are formed in a protruding shape at the front end of the flywheel 131, and the fan 111 is fixed by two screws 177, so that the rear end face of the fan 111 and the flywheel 131 are in contact with each other in the axial direction. If the fan 111 is fixed in this way, the fan 111 is fixed at two places in the circumferential direction, so that the runout is unlikely to occur. However, in this fixing method, as can be understood from FIG. 11, a circular planar region 175 is required on the inner peripheral side of the fan 111, and the fin 139 is not provided in that region, so the efficiency of the fan 111 is not sufficient. There was no. With this structure, it is necessary to increase the size of the fan 111 in order to ensure a sufficient air volume without disturbing the flow of the wind.

  The present invention has been made in view of the above-described background, and a main object of the present invention is to provide a blower device that is easy to center by improving the fan mounting structure.

  Another object of the present invention is to provide a blower device capable of improving the fan mounting structure and preventing the occurrence of blurring in the rotational direction.

  Of the inventions disclosed in the present application, typical features will be described as follows.

  According to one aspect of the present invention, in a blower device that is driven by an engine and rotates a fan via a flywheel, the flywheel and the fan are fixed to a drive shaft of the engine by an attachment member. On the tip side of the mounting member, there is formed a thread portion for passing through the mounting hole of the fan and fixing the fan with a bolt or nut, and a polygonal portion is formed near the middle in the axial direction of the mounting member. At the rear end of the fan, an inner wall portion is formed that can come into contact with the polygonal portion in the rotational direction. On the rear end side of the attachment member, a second screw portion that is screwed into screw means formed on the drive shaft is formed, and the flywheel is fixed to the drive shaft of the engine by the second screw portion.

  According to another aspect of the present invention, the protrusion is formed on the front surface in the axial direction of the flywheel, the substantially cylindrical protrusion extending in the axial direction from the rear end surface of the fan is formed, and the rear end of the protrusion On the outer peripheral side, the protruding portion and the protruding portion are contacted in the circumferential direction. The protrusion part of the fan has a space inside, and the inner wall part is formed inside the protrusion part. The inner wall portion has an inner diameter larger than that of the polygonal portion, and the polygonal portion is preferably formed in a hexagonal shape. The protrusions are provided continuously or discontinuously in the circumferential direction of the flywheel.

  According to the first aspect of the present invention, the polygonal portion is formed in the vicinity of the middle in the axial direction of the mounting member for attaching the flywheel and the fan, and the inner wall portion capable of contacting the polygonal portion in the rotational direction at the rear end of the fan. Therefore, it is possible to prevent the fan from rotating relative to the mounting member, and it is possible to effectively prevent rattling in the rotation direction of the fan.

  According to the second aspect of the present invention, the rear end side of the mounting member is formed with the second threaded portion that is screwed into the screw means formed on the drive shaft, and the flywheel becomes the drive shaft by the second threaded portion. Since it is fixed, the attachment member can also serve as a nut for attaching the flywheel to the drive shaft.

  According to the invention of claim 3, the substantially cylindrical protruding portion extending in the axial direction from the rear surface of the fan is formed, and the protruding portion and the protruding portion contact in the circumferential direction on the outer peripheral side of the rear end portion of the protruding portion. As a result, the fan can be centered, and even if fan runout occurs, the projecting part comes into contact with the projection and restricts the fan from moving in the radial direction. Can be prevented.

  According to the invention of claim 4, since the protrusion has a space on the inner side and the inner wall part is formed on the inner side of the protrusion, the protrusion has a space for accommodating the polygonal portion of the mounting member. The mounting member can be efficiently arranged in a small space.

  According to the invention of claim 5, since the inner diameter of the inner wall portion is larger than the outer shape of the polygonal portion, the rotational deviation of the fan can be prevented while maintaining the effect of centering the fan.

  According to the invention of claim 6, since the polygonal portion is hexagonal, the production is easy, and when fixing the mounting member to the drive shaft, it can be tightened with a general tool such as a spanner. It becomes.

  According to the seventh aspect of the present invention, since the protrusions are provided discontinuously in the circumferential direction of the flywheel, the shape change on the front side of the flywheel can be minimized. Moreover, since there is little possibility that rattling will occur if there are few protrusions, the fan can be accurately centered.

  The above and other objects and novel features of the present invention will become apparent from the following description and drawings.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, parts having the same function are denoted by the same reference numerals, and repeated description is omitted.

  FIG. 1 is a perspective view showing an entire blower apparatus 1 according to an embodiment of the present invention. The blower device 1 mainly includes a main housing 2, a two-cycle or four-cycle engine (not shown) housed in the main housing 2, a fan housing 3 that houses a fan for blowing air to be described later, and a fan A dustproof cover 4 that covers the suction port formed in the housing 3, an engine cover 5 that covers the engine portion, and a discharge pipe for discharging the wind generated by the fan. In the present embodiment, the discharge pipe is shown as an example constituted by two detachable pipes 19 and a nozzle 18. However, the discharge pipe is not limited to this configuration, and may be a combination of an arbitrary number of pipes 19 and nozzles 18, an arbitrary number of pipes 19, or only nozzles 18. Two leg portions 6a and 6b are formed at the lower part of the main housing 2 and the fan housing 3, and a leg portion 6c also serving as a handle is attached to the side of these leg portions.

  A handle portion 7 for carrying the blower device 1 and holding it during work is formed on the upper portion of the housing. As shown in FIG. 13, the blower device 1 can be held and operated by the handle portion 7. Further, if the blower device 1 is tilted sideways and the handle portion 7 is grasped with the right hand and the leg portion 6c is grasped with the left hand, the angle of the nozzle 18 at the tip can be rotated by 90 degrees. You can hold it.

  FIG. 2 is a perspective view showing the blower device 1 according to the embodiment of the present invention, and shows a state in which the dustproof cover 4 is opened. A throttle trigger 8 is provided below the handle portion 7 of the blower device 1, and a throttle adjustment lever 9 that can hold the throttle at an arbitrary position is provided on the front left side surface of the handle portion 7. An engine (not shown) is housed on the right side of the main housing 2. A fan housing 3 is attached to the left side of the main housing 2. The fan housing 3 covers the fan 11 and forms a flow path that guides the air flow generated by the fan 11 in the circumferential direction. In this embodiment, the left, right, and front / rear directions of the entire blower device 1 are described as pointing from the operator (FIG. 13) holding the handle. A discharge port 17 is formed at the circumferential end of the fan housing 3, and air discharged by the fan 11 is discharged forward from the discharge port 17. The circular discharge port 17 has one side surface in the axial direction formed by the main housing 2 and the other surface formed by the fan housing 3, and a plurality of ribs are formed on each inner peripheral portion. On the outer peripheral surface of the discharge port 17, projections 14 for attaching the pipe 19 or the nozzle 18 are provided at two locations separated by 180 degrees. The dust cover 4 is fixed to the fan housing 3 so that the dust cover 4 can be opened and closed by the mounting shaft 10, and is fixed to the main housing 2 by screws (not shown) through the screw holes 4 c in the closed state.

  In the fan housing 3, a plurality of ribs 3 a and 3 b provided with notches are formed in the vicinity of an outer edge portion to which the dust cover 4 is attached. When the dust cover 4 is closed, the fan housing 3 and the dust cover 4 are closed. An air flow path is formed between them. Further, the dustproof cover 4 is formed with a large number of slits 4a and 4b that allow air to pass therethrough and prevent large dust from entering. The dustproof cover 4 serves not only for dustproofing but also as a protector for preventing foreign matter from entering the rotating fan 11.

  As shown in FIG. 2, the dust cover 4 can be opened about 120 degrees at a rotation angle around the mounting shaft 10. Further, as shown in FIG. 14, the vacuum pipe 155 can be set in the suction port 13 to suck the fallen leaves and cut grass and collect them in the dust collection bag 159. The suction port 13 is a cylindrical opening extending from the fan housing 3 in the axial direction of the fan 13, and three protruding portions 13 a extending in the axial direction are formed in three circumferential directions near the opening, and the dust cover 4 is closed. Even at times, the air can be sucked from the gap between the protruding portions 13a. Such a shape of the suction port 13 can be easily manufactured by molding integrally with the fan housing 3 with plastic, for example.

  FIG. 3 is a left side view showing a state in which the dust cover 4 and the fan housing 3 are removed from the blower device 1. For example, the fan 11, which is a centrifugal fan, is directly or indirectly fixed to a crankshaft of an engine (not shown) by bolts 41. In FIG. 3, the fan 11 rotates counterclockwise to generate an air flow in the circumferential direction, and generates a strong air flow in the direction indicated by the three arrows in the figure depending on the shape of the housing. A plurality of ribs 81 and 82 for improving the strength of the housing are formed on the inner wall side in the vicinity of the discharge port 17. The ribs 81 and 82 not only improve the strength in the vicinity of the discharge port 17 of the main housing 2 but can also have an air flow rectifying effect.

  FIG. 4 is a cross-sectional view in a vertical plane passing through the crankshaft 43 of the blower device 1. The engine 20 is disposed in a region defined by the main housing 2 and the engine cover 5, and the flywheel 31 is fixed to the tip of a crankshaft 43 as a drive shaft by an attachment member 42. The fan 11 is fixed to the mounting member by a nut 41.

  The engine 20 that rotates the fan 11 is a two-cycle engine in this embodiment, and sends a mixture of fuel and air into a cylinder 21 that reciprocates up and down to a piston 24 and ignites at a predetermined timing by a spark plug 22. Thus, a driving force is obtained.

  A starter device 25 such as a recoil starter is attached to the crankshaft 43 on the side opposite to the flywheel 31. Note that a known device can be used for the starter device 25, and the internal structure of the recoil starter 25 is not shown in FIG. In addition, a fuel tank 27, a fuel tank cap 28, a carburetor (not shown), an air cleaner (not shown), and the like are attached around the engine 20, but the structure of the main part of the engine 20 is known and detailed. Description is omitted. As the engine 20, not only a 2-cycle engine but also a 4-cycle engine can be used.

  FIG. 5 is a partial cross-sectional view of a mounting portion of the fan 11 of FIG. In this specification, the direction shown in FIG. 5 is defined as “front-rear direction of the fan mounting portion”. The fan 11 is fixed to the attachment member 42 by a bolt 41 via an annular washer 46 on the front side of the through hole 45. The attachment member 42 is attached to the crankshaft 43 of the engine. A plurality of fins 44 are formed on the rear end surface of the flywheel 31, a protrusion 34 is formed on the front end surface 31 a, and the cylindrical portion 35 extends to the inner peripheral side of the protrusion on the rear end side of the fan 11. The protrusion part 34 and the cylindrical part 35 contact in radial direction. An opening 15 for projecting the mounting member 42 and the fan 11 from the engine side is provided in a part of the main housing 2, and a recess 16 is formed around the opening 15 when viewed from the front side (from the fan 11 side). It is disposed adjacent to a cylindrical rib 33 that protrudes from the rear surface 11a of the fan 11 and extends rearward in the axial direction. The recess 16 and the cylindrical rib 33 form a so-called labyrinth structure and reduce the occurrence of air flow from the fan 11 side to the engine side through the opening 15 of the main housing 2 or in the opposite direction. I am letting.

  FIG. 6 is a perspective view showing a mounting structure of the fan 11 and the flywheel 31 according to the embodiment of the present invention. A through hole 45 is formed at the center of the fan 11, and a circular flat region for attaching the washer 46 is formed around the through hole 45. The size of the flat region may be considerably smaller than the circular region of the prior art shown in FIG. Since the flat region has such a small diameter, the fin 39 can be formed to extend from the outer periphery to the inner periphery, so that the air volume can be increased while the fan 11 has the same outer diameter. Can be raised. The fan 11 can be made of a polymer resin such as plastic or a metal.

  The attachment member 42 includes a female screw portion 42a that meshes with a male screw portion formed on the crankshaft 43, a polygonal portion 42b that is formed near the middle in the axial direction, a main shaft portion 42c that contacts the through hole 45 of the fan 11, It is formed from four parts of a male screw part 42d having a male screw formed on the outer peripheral part for meshing the bolt 41, and is manufactured from a metal such as iron. Here, in FIG. 6, the screw thread of the male screw portion 42d is not shown. The polygonal portion 42b is formed in contact with the inner wall of the cylindrical portion 35 so that the two do not move relative to each other in the rotational direction. The polygonal part 42b is good in the shape which has at least 2 or more plane part, and is hexagonal like a volt | bolt in this embodiment. If the polygonal part 42b is thus formed in a hexagonal shape, the flywheel 31 is inserted into the crankshaft 43, and the female threaded part 42a of the mounting member 42 (this female threaded part serves as a tightening bolt) is formed on the crankshaft 43. What is necessary is just to make it mesh with the made external thread part. At this time, the polygonal portion 42b can be rotated by a known tool such as a spanner.

  On the front side of the flywheel 31, two protrusions 34 are integrally formed at positions separated by 180 degrees. The flywheel 31 is made of, for example, aluminum or other light metal.

  FIG. 7 is a perspective view showing a mounting structure of the fan 11 and the flywheel 31, and is a view seen from a direction different from FIG. The fan 11 is formed with a cylindrical portion 35 extending from the rear surface 11 a and a plurality of ribs 36 that are molded integrally with the cylindrical portion 35 and extend radially outward from the cylindrical portion 35. A second inner wall 35 a extending in parallel is formed inside the cylindrical portion 35, and the inner wall 35 a faces two sides of the polygonal portion 42 b of the mounting member 42. A rib 36 is formed on the rear surface side of the fan 11 and in the vicinity of the attachment portion with the cylindrical portion 35. This is provided to ensure the strength of the cylindrical portion 35. The rear surface 11a of the fan 11 is formed with a recess 38 having a partially reduced axial thickness, and as a result, a plurality of radially extending ribs 37 are formed. Further, a cylindrical rib 33 for forming a labyrinth structure is formed on the rear surface of the fan 11.

  FIG. 8 is a side view of the mounting portion of the fan 11. In this figure, the description of the main housing 2 is omitted. A magnet 32 is attached to the outer peripheral side of the flywheel 31 to determine the timing for supplying a high-voltage current to a spark plug (not shown) by detecting its rotational position.

  FIG. 9 (1) is a diagram showing a cross section taken along the line AA in FIG. 8 and the flywheel 31 side as seen from the AA cross section. Here, the inner shape of the two projecting portions 34 is an arc shape along the outer diameter of the cylindrical portion 35, and both are in contact with each other when the runout of the fan 11 occurs. Serves to limit movement in the circumferential direction. Therefore, the projecting portion 34 and the cylindrical portion 35 may be in contact with each other from the normal time, or may be arranged so as to be in non-contact with each other at a slight distance and in contact with each other when the runout occurs. Thus, the cylindrical part 35 and the rib 36 which contact in the circumferential direction are provided, and these restrict the movement of the fan 11 in the circumferential direction when the fan 11 rotates relative to the flywheel 61. When a slip occurs, the movement can be effectively limited.

  FIG. 9B is a diagram showing a state where the fan 11 is viewed from the BB cross section of FIG. 8 and the BB cross section. Here, between the inner wall 35a and the protrusion part 34, the reinforcing rib 35b extended in the up-down direction of drawing is formed.

  FIG. 10 is a view showing the cross-sectional shapes of the cylindrical portion 35 and the polygonal portion 42b in the AA cross section of FIG. FIG. 10A is a cross section of the cylindrical portion 35, and two parallel inner walls 35a for accommodating the polygonal portion 42b are formed in the cylindrical portion 35. FIG. The distance between the parallel inner walls 35a is W1. Reinforcing ribs 35b extending in the radial direction are formed on the outer peripheral side of the inner wall 35a. Both sides of the reinforcing ribs 35b have a thinned portion 35c. Although the reinforcing rib 35b has the effect of increasing the rigidity of the inner wall 35a, the reinforcing rib 35b and the lightening portion 35c are provided mainly for ease of manufacturing, and all of these portions are provided without these. The cylindrical portion 35 may be configured to be filled with resin.

  FIG. 10B is a cross section of the polygonal part 42b, and the distance between the two sides corresponding to the inner wall 35a is W2. In the present embodiment, W1 may be slightly larger than W2 and may be configured to have a slight gap. Although it is conceivable that the polygonal part 42b is press-fitted into the cylindrical part 35 to be firmly fixed, in that case, it cannot be adjusted when the core is displaced at the time of press-fitting. It is preferable to allow the fan 11 to be centered so as to be separated from each other or lightly contacted.

  With this configuration, it is possible to prevent the fan 11 from rotating relative to the mounting member 42 by the polygonal portion 42b coming into contact with the inner wall 35a. Serves as a stop function. For this reason, the other four sides of the polygonal part 42b do not have to contact the inner wall 35a. In order to achieve the function of preventing rotation, the cross section of the polygonal portion 42b is not limited to a hexagonal shape, and may have other shapes as long as it has at least two linear contours.

  In order to achieve the above-described anti-rotation function, it is conceivable to form a rib or the like on the outer peripheral side of the cylindrical portion 35. However, if a rib is provided on the outer peripheral side of the cylindrical portion 35, a necessary space increases. Therefore, the shape of the present embodiment is such that the rib on the rear surface of the fan 11 does not spread in the radial direction by preventing the rotation on the inner side of the cylindrical portion 35 as compared to providing a rotation prevention mechanism on the outer peripheral side. This has the advantage that the opening 15 can be made small. And if the opening 15 of the main housing 2 becomes small, there exists an advantage that it is difficult for dust to enter into the engine 20 side from the fan 11 side.

  As described above, according to the mounting structure of the fan 11 according to the present embodiment, the projecting portion 34 and the cylindrical portion 35 that are members in contact with each other in the radial direction overlap each other in the radial direction in the cross section perpendicular to the axial direction. Thus, even if fan runout occurs, the fan contacts each other and restricts the movement of the fan in the radial direction. Therefore, vibration and shake of the fan can be effectively prevented. Moreover, since the protrusion part 34 is provided in the circumferential direction continuously or discontinuously, since the shape and arrangement | positioning of the protrusion part 34 can be determined according to the shape of the flywheel 31 and the fan 11, these are integrated. It can be easily manufactured by molding. Moreover, the number of parts can be reduced by manufacturing by integral molding.

  In addition, the attachment structure of the fan 11 by this invention is not limited to description of embodiment, A various deformation | transformation is possible. For example, although it provided in two places of the circumferential direction as the protrusion part 34, you may provide three or more places. Moreover, you may provide continuously as a cylindrical rib instead of providing intermittently in the circumferential direction. Further, although the protruding portion 34 is disposed on the outer peripheral side of the cylindrical portion 35, it may be provided on the inner peripheral side of the cylindrical portion 35. Furthermore, although the cylindrical portion 35 has a shape that is continuous in the circumferential direction, a notch or the like may be provided to make the shape non-continuous, and a contact member may be provided only at a location that contacts the cylindrical portion 35.

It is a perspective view showing the whole blower device concerning the embodiment of the present invention. It is a perspective view which shows the state which opened the dustproof cover 4 of the blower apparatus 1 of the blower apparatus which concerns on embodiment of this invention. It is a side view which shows the state which removed the dust-proof cover 4 and the fan housing 3 of the blower apparatus which concerns on embodiment of this invention. It is sectional drawing in the vertical plane which passes along the crankshaft 43 of the blower apparatus by embodiment of this invention. It is sectional drawing which shows the attachment structure of the fan 11 by embodiment of this invention. It is a perspective view which shows the attachment structure of the fan 11 and the flywheel 31 by embodiment of this invention. It is a perspective view which shows the attachment structure of the fan 11 and flywheel 31 by embodiment of this invention, and is the figure seen from the direction different from FIG. It is a side view of the attachment part of the fan 11 by embodiment of this invention. (1) is the figure which shows the state which looked at the flywheel 31 side from the AA cross section and AA cross section of FIG. 8, (2) from the BB cross section and BB cross section of FIG. It is a figure which shows the state which looked at the fan. It is a figure which shows the cross-sectional shape of the cylindrical part 35 and the polygonal part 42b in the AA cross section of FIG. 8, (1) is sectional drawing of the cylindrical part 35, (2) is sectional drawing of the polygonal part 42b. It is a perspective view which shows the shape of the fan 111 by a prior art. It is sectional drawing which shows the attachment structure of the fan 111 by a prior art. It is a figure for demonstrating the blower apparatus by the prior art, and its usage. It is a figure for demonstrating the usage which uses the blower apparatus by a prior art as a suction device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blower apparatus 2 Main housing 3 Fan housing 3a, 3b Rib 4 Dust-proof cover
4a, 4b (Dustproof cover) slit 4c Screw hole 5 Engine cover 6a, 6b, 6c Leg part 7 Handle part 8 Throttle trigger 9 Throttle adjusting lever 10 Mounting shaft 11 Fan 11a (Fan) rear face 13 Suction port 13a Protruding part 14 Protrusion 15 (main housing) opening
16 Recess (of main housing)
17 Discharge port 18 Nozzle 19 Pipe 20 Engine 21 Cylinder 22 Spark plug 24 Piston 25 Starter device 27 Fuel tank 28 Fuel tank cap 31 Flywheel 31a (Flywheel) rear end surface 32 Magnet 33 Cylindrical rib 34 (Flywheel) protrusion 35 (Fan) cylindrical part 35a (Cylindrical part) inner wall 35b Reinforcement rib 35c Thickening part 36, 37 (Fan) rib 38 Recess 39 Fin 41 Bolt 42 Mounting member 42a Female thread part 42b Polygonal part 42c Main shaft part 42d Male thread Part 43 Crankshaft 44 Fin 45 Through-hole 46 Washer 100 Blow object 101 Blower device 103 Fan housing 107 Handle part 110 Installation position 118 Nozzle 119 Pipe 144 Screw 150 Switch cover

Claims (7)

In a blower device driven by an engine and rotating a fan via a flywheel,
The flywheel and the fan are fixed to a drive shaft of the engine by an attachment member,
A threaded portion is formed on the front end side of the mounting member so as to pass through the mounting hole of the fan and fix the fan with a bolt or a nut, and a polygonal portion is formed near the axial middle of the mounting member. And
The blower device according to claim 1, wherein an inner wall portion capable of contacting the polygonal portion in a rotational direction is formed at a rear end of the fan.   A rear end side of the mounting member is formed with a second screw portion that is screwed into a screw means formed on the drive shaft, and the flywheel is fixed to the drive shaft by the second screw portion. The blower device according to claim 1. A protrusion is formed on the front surface in the axial direction of the flywheel,
A substantially cylindrical projecting portion extending in the axial direction from the rear end surface of the fan is formed, and the projecting portion and the projecting portion contact in the circumferential direction on the outer peripheral side of the rear end portion of the projecting portion. The blower device according to claim 1 or 2.   The blower device according to claim 3, wherein the projecting portion has a space inside, and the inner wall portion is formed inside the projecting portion.   The blower device according to any one of claims 1 to 4, wherein an inner diameter of the inner wall portion is larger than an outer shape of the polygonal portion.   The blower device according to claim 1, wherein the polygonal portion has a hexagonal shape.   The blower device according to any one of claims 3 to 6, wherein the protrusion is provided discontinuously in a circumferential direction of the flywheel.

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