Propeller fans and ventilation fans

Abstract

To provide a propeller fan that allows for easy removal during ventilation fan cleaning and suppresses increases in material costs and assembly costs for its components. [Solution] The propeller fan 10 includes a boss portion 21 that rotates around a rotation axis A by the drive of a motor 17, an insertion portion 23 provided on the boss portion 21 into which the shaft 18 of the motor 17 is detachably inserted, a plurality of blades 31, 32, 33 provided on the outer peripheral surface 22a of the cylindrical wall 22 of the boss portion 21 and arranged at intervals in the rotational direction of the rotation axis A, and a rib 24 provided between adjacent pairs of blades 31, 32 on the outer peripheral surface 22a and extending in the radial direction of the rotation axis.

Description

Technical Field

[0001] The present disclosure relates to propeller fans and ventilation fans.

Background Art

[0002] Among ventilation fans mounted on ceilings or walls, there is known a structure that allows a propeller fan to be detached from a motor shaft without using special tools, so that users can easily clean the ventilation fan. However, during normal use, the propeller fan must be securely fixed to the motor shaft to avoid problems such as idling of the motor or falling off of the blades. Patent Document 1 describes a ventilation fan in which a propeller fan having a threaded boss portion is coupled to a motor shaft via a spinner, so that the propeller fan can be securely fixed to the motor shaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the ventilation fan described in Patent Document 1, the coupling between the propeller fan and the motor shaft is achieved by screw fastening using a spinner. For this reason, when detaching the propeller fan from the motor shaft, it is necessary to hold the propeller fan with one hand and rotate the spinner with the other hand, which poses the problem that the detachment operation is not easy. Further, the addition of the spinner as a separate component in addition to the propeller fan poses the problem that the material cost and assembly cost of the constituent parts increase.

[0005] This disclosure was made to solve the above-mentioned problems, and aims to provide a propeller fan and ventilation fan that can be easily removed during cleaning and that can suppress increases in material costs and assembly costs of the components. [Means for solving the problem]

[0006] The propeller fan according to this disclosure comprises a boss portion that rotates around a rotation axis by the drive of a motor, an insertion portion provided on the boss portion into which the motor shaft is detachably inserted, a plurality of blades provided on the outer circumferential surface of the cylindrical wall of the boss portion and arranged at intervals in the rotational direction of the rotation axis, and ribs provided between adjacent pairs of blades on the outer circumferential surface and extending in the radial direction of the rotation axis. [Effects of the Invention]

[0007] The propeller fan and ventilation fan related to this disclosure have the effect of making it easy to remove the fan when cleaning the ventilation fan, and suppressing increases in the material cost and assembly cost of the components. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing a ventilation fan according to Embodiment 1. [Figure 2] This is a perspective view showing a propeller fan according to Embodiment 1. [Figure 3] This is a front view showing a propeller fan according to Embodiment 1. [Figure 4] This is a side view showing the side shape of a propeller fan according to Embodiment 1. [Figure 5] This is a partial cross-sectional view showing the cross-sectional shape of the cylindrical wall and ribs of the boss section. [Figure 6] (a) is a diagram showing the external appearance of a propeller fan. (b) is a close-up view showing the detailed shape of the ribs. [Figure 7] This is a cross-sectional view showing the schematic structure of a mold for injection molding. [Figure 8]This is a cross-sectional view showing the schematic structure of an injection molding die equipped with a sliding mechanism. [Figure 9] This is a cross-sectional view showing the schematic structure of a mold for injection molding. [Figure 10] This is a cross-sectional view showing the schematic structure of a mold for injection molding. [Modes for carrying out the invention]

[0009] The embodiments for implementing this disclosure will be described in detail below with reference to the attached drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations of such parts are simplified or omitted as appropriate. Also, the size relationships of the components in each drawing may differ from those of the actual components.

[0010] Embodiment 1. Figure 1 is a cross-sectional view showing a ventilation fan 10 according to Embodiment 1. The ventilation fan 10 is mounted on the wall of a building and discharges indoor air to the outside through a ventilation duct that connects the inside and outside of the building. As shown in Figure 1, the ventilation fan 10 comprises a main body 11, an intake port 12 provided on the front side of the main body 11 (the indoor side when mounted on the wall of a building), and a duct connection part 13 provided on the rear side of the main body 11 (the outdoor side when mounted on the wall of a building). The ventilation fan 10 also comprises a blower 14 mounted inside the main body 11 that forms an exhaust flow from the intake port 12 toward the duct connection part 13, and a decorative grille 15 that covers the front side of the main body 11 and prevents people from inadvertently putting their hands or objects inside from indoors.

[0011] The main body 11 has an outwardly protruding mounting flange 16, and the main body 11 is attached to the wall of the building via the mounting flange 16. The blower 14 comprises a motor 17 and a propeller fan 20 attached to the motor 17. The motor 17 is mounted on the rear side of the main body 11. The motor 17 is provided with a motor shaft 18 that extends in the direction of the intake port 12.

[0012] The propeller fan 20 includes a cylindrical boss portion 21 that rotates about the rotation axis A by the drive of the motor 17. The boss portion 21 includes a cylindrical wall 22, and an insertion portion 23 into which the motor shaft 18 is detachably press-fitted and fixed. Then, the motor shaft 18 press-fitted and fixed in the insertion portion 23 is rotated by the drive of the motor 17, whereby the boss portion 21 rotates about the rotation axis A. The inner diameter of the insertion portion 23 is smaller than the outer diameter of the motor shaft 18. Therefore, by press-fitting the motor shaft 18 into the insertion portion 23, the propeller fan 20 is reliably fixed to the motor shaft 18. In FIG. 1, the insertion portion 23 does not penetrate the boss portion 21, but the insertion portion 23 may penetrate the boss portion 21.

[0013] A hook portion 15a is formed on the decorative grill 15, and a grill fixing portion 16a is formed on the outer peripheral portion of the mounting flange 16. Then, the decorative grill 15 is fixed to the main body 11 by hooking the hook portion 15a to the grill fixing portion 16a.

[0014] FIG. 2 is a perspective view showing the propeller fan 20 according to the first embodiment. Further, FIG. 3 is a front view showing the propeller fan 20 according to the first embodiment. The propeller fan 20 is an axial fan. As shown in FIGS. 2 and 3, the propeller fan 20 includes three blades 31, 32, 33. The three blades 31, 32, 33 are provided on the outer peripheral surface 22a of the cylindrical wall 22 included in the boss portion 21, and are arranged at intervals in the rotation direction of the rotation axis A. Although the number of blades in the present embodiment is three, it may be four or more.

[0015] The blade 31 has a leading edge portion 31a, a trailing edge portion 31b, an outer peripheral edge portion 31c, and an inner peripheral edge portion 31d. Further, the blade 32 has a leading edge portion 32a, a trailing edge portion 32b, an outer peripheral edge portion 32c, and an inner peripheral edge portion 32d. Furthermore, the blade 33 has a leading edge portion 33a, a trailing edge portion 33b, an outer peripheral edge portion 33c, and an inner peripheral edge portion 33d. The leading edge portions 31a, 32a, and 33a are edges on the front side in the rotation direction of the propeller fan 20 on the blades 31, 32, and 33, and are located on the upstream side of the airflow B generated by the rotation of the propeller fan 20. The trailing edge portions 31b, 32b, and 33b are edges on the rear side in the rotation direction of the propeller fan 20 on the blades 31, 32, and 33, and are located on the downstream side of the airflow B generated by the rotation of the propeller fan 20.

[0016] The outer peripheral edge portions 31c, 32c, and 33c are edges that connect the radially outer ends of the leading edge portions 31a, 32a, and 33a and the radially outer ends of the trailing edge portions 31b, 32b, and 33b in an arc shape. The inner peripheral edge portions 31d, 32d, and 33d are edges that connect the radially inner ends of the leading edge portions 31a, 32a, and 33a and the radially inner ends of the trailing edge portions 31b, 32b, and 33b in an arc shape. The inner peripheral edge portions 31d, 32d, and 33d are in contact with the outer peripheral surface 22a of the boss portion 21, and the blades 31, 32, and 33 are connected to the outer peripheral surface 22a of the boss portion 21 via the inner peripheral edge portions 31d, 32d, and 33d.

[0017] As shown in FIG. 3, a rib 24 extending in the radial direction of the rotation axis A is provided between the pair of adjacent blades 31 and 32 on the outer peripheral surface 22a of the boss portion 21. The rib 24 is disposed in a region C between projection lines obtained by projecting the trailing edge portion 31b of the blade 31 and the leading edge portion 32a of the blade 32 onto a plane perpendicular to the rotation axis A, respectively. The ribs 24 are also provided between the blade 32 and the blade 33 and between the blade 33 and the blade 31, respectively.

[0018] When removing the propeller fan 20 from the ventilation fan 10 for cleaning, the user first removes the decorative grille 15 from the main body 11. Once the decorative grille 15 is removed, the propeller fan 20, located inside the main body 11, is exposed. The user can then remove the propeller fan 20 from the motor 17 by inserting their hand into the main body 11 through the intake port 12 and pulling it outwards while grasping the boss portion 21 of the propeller fan 20 with one hand. The propeller fan 20 has ribs 24 formed on it, and the ribs 24 can be used as a grip for the user's fingertips when grasping the boss portion 21, thereby reducing the gripping force required to pull it out. Therefore, the propeller fan 20 can be safely removed even on unstable scaffolding such as a stepladder or stool.

[0019] Furthermore, when pulling out the propeller fan 20, if the blades 31, 32, and 33 are used as a grip for the fingertips, an undue force may be applied to the blades 31, 32, and 33, potentially causing distortion or damage to them. However, since the propeller fan 20 according to this embodiment is provided with ribs 24, the propeller fan 20 can be easily pulled out from the motor shaft 18 without applying an undue force to the blades 31, 32, and 33 by using the ribs 24 as a grip for the fingertips.

[0020] Furthermore, the propeller fan 20 has its blades 31, 32, and 33 and ribs 24 molded integrally with the boss portion 21. This helps to suppress increases in material costs and assembly costs for the components.

[0021] Figure 4 is a side view showing the side shape of the propeller fan 20 according to Embodiment 1. In the following description, when referring to the blades 31, 32, and 33 collectively, they will be referred to as blade 30. Also, when referring to the inner peripheral edges 31d, 32d, and 33d collectively, they will be referred to as inner peripheral edge 30d. As shown in Figure 4, the inner peripheral edge 30d of the wing 30 extends in a direction intersecting the rotation direction of the rotation axis A. The rib 24 is located between a virtual plane D that passes through one end of the inner peripheral edge 30d (the upstream end of the airflow B generated by the rotation of the propeller fan 20) and is perpendicular to the rotation axis A, and a virtual plane E that passes through the other end of the inner peripheral edge 30d (the downstream end of the airflow B generated by the rotation of the propeller fan 20) and is perpendicular to the rotation axis A.

[0022] As described above, since the inner peripheral edge 30d of the wing 30 is positioned at an angle to the rotation direction of the rotation axis A, the width of the inner peripheral edge 30d in the axial direction of the rotation axis A can be narrowed compared to the case where the inner peripheral edge 30d extends in the axial direction of the rotation axis A, thereby enabling a miniaturization of the propeller fan 20. Furthermore, on the outer peripheral surface 22a of the boss portion 21, the inner peripheral edges 30d of multiple blades 30 are positioned between virtual surfaces D and E in the rotational direction of the rotation axis A. Since the boss portion 21 and the blades 30 are integrally molded, the region between virtual surfaces D and E has higher strength and is less prone to deformation than the region outside of this area. Therefore, by placing the ribs 24 in the region between virtual surfaces D and E, deformation of the boss portion 21 caused by the user grasping the ribs 24 and pulling out the propeller fan 20 can be suppressed.

[0023] Furthermore, as shown in Figure 4, when the propeller fan 20 is viewed from the side, the ribs 24 are formed with the longitudinal direction being the direction in which the inner peripheral edge 30d of the blade 30 extends. The airflow B generated by the rotation of the propeller fan 20 travels between adjacent blades 30 in the direction in which the inner peripheral edge 30d extends. Therefore, by aligning the longitudinal direction of the ribs 24 with the direction in which the inner peripheral edge 30d extends, turbulence of the airflow caused by the ribs 24 can be minimized, preventing deterioration of noise and fan efficiency due to airflow turbulence.

[0024] Figure 5 is a partial cross-sectional view showing the cross-sectional shape of the cylindrical wall 22 and rib 24 of the boss portion 21. Note that the cross-sectional view in Figure 5 is a view in which the plane passing through the rotation axis A and perpendicular to the plane of the paper in Figure 4 is used as the cutting plane. As shown in Figure 5, the width LA and height LB of the rib 24 are greater than or equal to the plate thickness LC of the cylindrical wall 22. This configuration ensures that the rib 24 has sufficient strength to prevent deformation when gripped by hand. As a result, even after the propeller fan 20 has been removed many times, the rib 24 maintains its original shape, and the user can securely grip the rib 24.

[0025] Figure 6(a) shows the external appearance of the propeller fan 20. Figure 6(b) is a partially enlarged view showing the detailed shape of the rib 24. As shown in Figures 6(a) and 6(b), the height of the rib side surface 24a on the front side in the rotational direction of the rotation axis A is lower than the height of the rib side surface 24b on the rear side in the rotational direction of the rotation axis.

[0026] If the rib side 24b is made to the same height as the rib side 24a, the overall height of the rib 24 will be reduced, making it difficult for the user to grasp the rib 24. On the other hand, if the rib side 24a is made to the same height as the rib side 24b, the overall height of the rib 24 will be increased, making it easier for the user to grasp the rib 24, but the turbulence of the airflow caused by the rib 24 will increase. Therefore, by making the rib side 24a lower than the height of the rib side 24b, it is possible to ensure that the user can firmly grasp the rib 24 while minimizing the turbulence of the airflow caused by the rib 24. As a result, the deterioration of noise generated by the rotation of the propeller fan 20 can be suppressed.

[0027] Next, it will be explained that the propeller fan 20 according to this embodiment has a shape suitable for molding by injection molding. First, the injection molding of the propeller fan 40 according to the comparative example will be described. As shown in Figure 7, the propeller fan 40 according to the comparative example has a shape in which the blades 41 and ribs 42 are aligned in the axial direction of the rotation axis A. The mold 50 has a fixed cavity 51 and a movable core 52, and molten resin is filled into the molding space with the core 52 in contact with the cavity 51. After the molten resin hardens due to cooling, the core 52 is moved to separate the cavity 51 and the core 52, thereby molding the propeller fan 40.

[0028] Here, the propeller fan 40 on the cavity 51 side has no part to fit into, so the propeller fan 40 can be easily removed from the cavity 51. However, the propeller fan 40 on the core 52 side has a rib 42 that protrudes radially in the direction of the rotation axis A, so the rib 42 fits into the core 52, making it impossible to remove the propeller fan 40 from the core 52.

[0029] Therefore, as shown in Figure 8, to mold the propeller fan 40 according to the comparative example, it is necessary to use a mold 60 with an added slide core 61. In this case, since the slide core 61 is positioned in the area between the blade 41 and the rib 42, when removing the propeller fan 40 from the mold 60, the core 52 moves away from the cavity 51, and the slide core 61 moves away from the cavity 51 in a direction perpendicular to the direction in which the core 52 moves. As a result, the propeller fan 40 can be removed from the mold 60.

[0030] Next, the injection molding of the propeller fan 20 according to this embodiment will be described. Figures 9 and 10 are cross-sectional views showing the schematic structure of the mold 70 for injection molding. Figure 9 is a cross-sectional view taken at a position that passes through the rotation axis A and includes a pair of blades 31 and 32. Since the rib 24 of the propeller fan 20 is provided between the pair of blades 31 and 32, the rib 24 is not shown in this cross-sectional view. Figure 10 is a cross-sectional view taken at a position that passes through the rotation axis A and includes the blades 31 and rib 24. Since the rib 24 of the propeller fan 20 is provided between the pair of blades 31 and 32, the blade 32 is not shown in this cross-sectional view.

[0031] As shown in Figures 9 and 10, the mold 70 comprises a fixed cavity 71 and a movable core 72. Molten resin is filled into the molding space with the core 72 in contact with the cavity 71. After the molten resin hardens due to cooling, the core 72 is moved so that the cavity 71 and the core 72 separate, thereby molding the propeller fan 20.

[0032] In Figure 9, the mold 70 is constructed so that the cavity 71 and the core 72 can be separated at the positions of the blade 31 and blade 32. Therefore, neither the blade 31 nor the blade 32 can become trapped in the cavity 71 or the core 72. As a result, the propeller fan 20 can be easily removed from the mold 70. In Figure 10, the mold 70 is constructed so that the cavity 71 and the core 72 can be separated at the positions of the blade 31 and the rib 24. Therefore, neither the blade 31 nor the rib 24 can become trapped in the cavity 71 or the core 72. As a result, the propeller fan 20 can be easily removed from the mold 70.

[0033] As described above, the propeller fan 20 according to this embodiment can be easily injection-molded using a mold 70 without a sliding mechanism, thus reducing the molding time that would otherwise be required to operate the sliding mechanism, and thus reducing the cost of creating a mold for injection molding the propeller fan 20.

[0034] In this embodiment, an example of application to a propeller fan for pipes was described, but it can also be applied to other blowers, ventilation fans, and air conditioning equipment. Furthermore, the configuration shown in this embodiment is merely an example and can be combined with other known technologies. In addition, it is possible to omit or modify parts of the configuration without departing from the spirit of the invention.

[0035] The various aspects of this disclosure are summarized below as an appendix.

[0036] (Note 1) A boss that rotates around a rotation axis driven by a motor, An insertion portion is provided on the boss portion for detachably inserting the motor shaft, A plurality of wings are provided on the outer circumferential surface of the cylindrical wall of the boss portion and are arranged at intervals in the rotational direction of the rotation axis, A propeller fan comprising a rib provided between an adjacent pair of blades on the outer circumferential surface and extending radially along the axis of rotation. (Note 2) The propeller fan as described in Appendix 1, wherein the wings and ribs are molded integrally with the boss portion. (Note 3) The inner peripheral edge of the wing, which is the side connected to the boss portion, extends in a direction intersecting the rotational direction of the rotation axis, The rib is located between a plane passing through one end of the inner peripheral edge of the wing and perpendicular to the axis of rotation and a plane passing through the other end of the inner peripheral edge of the wing and perpendicular to the axis of rotation, as described in Appendix 1 or Appendix 2 of the propeller fan. (Note 4) A propeller fan as described in any one of the appendices 1 to 3, wherein the height and width of the ribs are greater than or equal to the thickness of the cylindrical wall. (Note 5) A propeller fan according to any one of the appendices 1 to 4, wherein the height of the side surface of the rib located on the front side in the direction of rotation of the rotating shaft is lower than the height of the side surface of the rib located on the rear side in the direction of rotation of the rotating shaft. (Note 6) The propeller fan according to any one of the appendices 1 to 5, wherein the rib is formed with the direction in which the inner peripheral edge of the wing, which is the connection side with the boss, extends as the longitudinal direction. (Note 7) A blower having a propeller fan as described in any one of the appendices 1 to 6 and the motor to which the propeller fan is attached, A ventilation fan comprising a main body with the aforementioned blower installed inside. [Explanation of symbols]

[0037] 10 Ventilation fan, 11 Main body, 12 Intake port, 13 Duct connection part, 14 Blower, 15 Decorative grille, 16 Mounting flange, 17 Motor, 18 Motor shaft (shaft), 20 Propeller fan, 21 Boss part, 22 Cylinder wall, 22a Outer surface, 23 Insertion part, 24 Rib, 30, 31, 32, 33 Blades, 30d, 31d, 32d, 33d Inner peripheral edge, A Rotation axis, B Airflow, C Region, D, E Virtual surface (plane).

Claims

1. A boss that rotates around a rotation axis driven by a motor, An insertion portion is provided on the boss portion for detachably inserting the motor shaft, A plurality of wings are provided on the outer circumferential surface of the cylindrical wall of the boss portion and are arranged at intervals in the rotational direction of the rotation axis, A propeller fan comprising a rib provided between an adjacent pair of blades on the outer circumferential surface and extending radially along the axis of rotation.

2. The propeller fan according to claim 1, wherein the wings and ribs are molded integrally with the boss portion.

3. The inner peripheral edge of the wing, which is the side connected to the boss portion, extends in a direction intersecting the rotational direction of the rotation axis, The propeller fan according to claim 1 or claim 2, wherein the rib is located between a plane passing through one end of the inner peripheral edge of the wing and perpendicular to the axis of rotation and a plane passing through the other end of the inner peripheral edge of the wing and perpendicular to the axis of rotation.

4. The propeller fan according to claim 1 or claim 2, wherein the height and width of the ribs are greater than or equal to the thickness of the cylindrical wall.

5. The propeller fan according to claim 1 or claim 2, wherein the height of the side surface of the rib located on the front side in the rotational direction of the rotating shaft is lower than the height of the side surface of the rib located on the rear side in the rotational direction of the rotating shaft.

6. The propeller fan according to claim 1 or claim 2, wherein the rib is formed with the direction in which the inner peripheral edge of the wing, which is the connection side with the boss, extends as the longitudinal direction.

7. A blower having a propeller fan according to claim 1 or claim 2 and the motor to which the propeller fan is attached, A ventilation fan comprising a main body with the aforementioned blower installed inside.

Images