JP2007225008A - Fixing structure of rotor and rotating shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable rotor and rotating shaft fixing structure having simple construction eliminating the need for special assembling devices and fixing means without depending on the diameter of a rotating shaft. <P>SOLUTION: The rotating shaft 6 has a tap screw portion 61 and a stepped portion 62 at predetermined sites and a rotor 4 has a boss portion 41 with a preparing hole 41a whose inner diameter is fitted to the tap screw portion. The tap screw portion of the rotating shaft is screwed into the preparing hole of the rotor, and the boss portion of the rotor is seated and fastened onto the stepped portion. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is, for example, mounted on a household appliance such as a dishwasher, an electromagnetic cooker, an outdoor unit of an air conditioner, and the like, and can be preferably used for, for example, a blower or a cooling fan of an electric motor. Concerning structure.

  Hereinafter, a dishwasher will be described as an example. In the dishwasher, a rotating body made of a resin impeller is fixed to a rotating shaft consisting of a drive shaft (output shaft) of an electric motor as a blower for drying the hot air heated by a heater against the washed dishes. Things are used. Further, a rotating body composed of a resin cooling fan for washing or cooling the drive motor of the drainage pump is similarly fixed to the drive shaft of the motor and accommodated inside the housing of the product. The fixed structure of the rotating body and the rotating shaft of the electric motor is provided with a stopper and a rotation stopper, and the rotating body is synchronized with the rotating shaft of the electric motor and is not separated from the shaft. The function is realized.

Furthermore, since these rotating bodies are mounted inside the housing of household electrical appliances, a large amount is required for repair. For this reason, the same high reliability as an electric motor is calculated | required. In addition, the rotating body is not frequently attached and detached every time it is cleaned, such as a general household ventilation fan, but is removed from the home appliance after being removed from the home appliance together with the motor when the motor fails. As a result, since there are very few opportunities to remove the shaft, it is possible to provide a shaft mounting structure that can be easily removed to some extent.
The conventional fixing structure will be described separately for a case where the rotation shaft is thick and a case where the rotation shaft is thin. The thick rotating shaft and the rotating body are fixed by forming a through hole in the rotating shaft and the rotating body, inserting a pin, or fixing the rotating shaft and the rotating body engaged with a D-shaped cross section with a set screw. Or was realized. On the other hand, as a fastening method applicable to a thin rotating shaft, press-fitting of the rotating shaft into a shaft hole provided in the rotating body, installation of a retaining ring having elasticity to the rotating shaft, and a screw portion formed at the tip of the rotating shaft For example, fixing nuts to

However, these fixing structures have the following problems, and a fixing structure with fewer components and high reliability is required.
-Components other than the rotating body and rotating shaft are indispensable.
・ Applicable even when the rotating shaft is thin and the press-fitting method with few components is a fastening method that uses resin elasticity. Stress is always generated, dimensional accuracy is controlled, and creep resistance characteristics considering the surrounding environment It is necessary to ensure.

In order to solve the above-mentioned problem, for example, there is a rotating shaft having a snap fit structure provided on a rotating body and a groove or notch that engages with the rotating body, or a planar cut portion (for example, (See Patent Documents 1 and 2).
In addition, a protrusion is installed on the inner diameter of the boss portion of the rotating body into which the rotating shaft is inserted, and a rotating shaft having a recess to be engaged with the protrusion is used to rotate the resin rotating body in a high temperature environment to rotate the inner diameter of the boss. Some have been made larger than the shaft diameter and assembled to be firmly fastened after cooling (for example, see Patent Document 3).

Japanese Patent Laid-Open No. 06-66296 (paragraph number 0005, second page, FIG. 1) Japanese Patent Laying-Open No. 2003-106294 (3rd page, paragraph numbers 0010 to 0011, FIG. 1) JP 2000-14085 A (paragraph numbers 0007 to 0009, second page, FIG. 1)

  Unlike the press-fit fastening method, stress is not always generated in the shaft-attached structure using the former snap-fit structure. However, while the rotating shaft is rotated by the motor operation, the rotating body receives a force in the direction to be removed from the rotating shaft due to uneven pressure distribution in the casing, impact force due to vibration, etc. Repeated stress is generated at the fitting root. Therefore, in order to ensure high reliability, it is necessary to pay sufficient attention to the characteristics of the resin used and the molding accuracy. Furthermore, when the rotation shaft is thin, the non-circular anti-rotation effect such as a D-shaped cross-sectional shape is reduced, so that sufficient shaft attachment cannot be achieved.

  When the latter resin rotating body is fixed by thermally expanding in a high temperature environment, it is applicable even if the rotating shaft is thin, but a high temperature device that sufficiently expands the cooling fan is required. Since it is in a press-fit state after being cooled, it is necessary to secure creep resistance characteristics in consideration of the surrounding environment as well as management of dimensional accuracy.

  The present invention has been made to solve the above-described problems of the prior art, has a simple structure, does not depend on the diameter of the rotating shaft, and does not require a special assembly device, and has high reliability. It aims at providing the fixed structure of a rotary body and a rotating shaft.

  In the fixing structure of the rotating body and the rotating shaft according to the present invention, a tap screw and a stepped portion made of a step having a diameter larger than the tap screw are provided in a predetermined portion of the rotating shaft, and the rotating body has an inner diameter suitable for the tap screw. A boss portion having a pilot hole is provided, and a tap screw of the rotating shaft is screwed into the pilot hole and fixed to the stepped portion.

  According to the present invention, it is possible to reduce the cost because it can be mounted and fixed with only the rotating body and the rotating shaft, which are the minimum components. In addition, since fastening by plastic deformation rather than elastic deformation is used, it is difficult to be affected by stress relaxation, a highly reliable fixing structure can be realized, and dimensional management of the pilot hole diameter provided in the boss portion of the rotating body is easy. Thus, mold costs and maintenance costs can be reduced. Furthermore, a remarkable effect that is not possible in the past can be obtained such that the tap screw fastening strength data can be used and the reliability evaluation test can be shortened.

Embodiment 1 FIG.
1 to 5 illustrate a case where the structure for fixing a rotating body and a rotating shaft according to Embodiment 1 of the present invention is applied to a drying fan of a dishwasher, and FIG. 1 is a resin as a rotating body. FIG. 2 is a partially sectional assembly view showing an electric motor having a manufactured axial flow fan and a drive shaft as a rotating shaft. FIG. 2 is a tightening amount of a tap screw and a required tightening torque with respect to a boss portion of the axial flow fan shown in FIG. 3 is a characteristic diagram measured for the relationship, FIG. 3 is a diagram for explaining the operation when a rotating body and a rotating shaft shown in FIG. 1 are fixed, and FIG. 4 shows the rotating body and the rotating shaft shown in FIG. FIG. 5 is an explanatory view showing an example of an assembling jig used for fixing and its assembling operation, and FIG. 5 is a main part showing an entire configuration when the rotating body and rotating shaft shown in FIG. 1 are fixed to a dishwasher. It is sectional drawing. Throughout the drawings, the same reference numerals indicate the same or corresponding parts, and overlapping description is avoided.

  As illustrated in FIG. 5, the dishwasher 1 is equipped with a blower 3 in the washing tub 2 to dry the dishes (not shown) after washing. In this example, an axial fan is used as the rotating body 4 and the blower 3 is installed on the back surface of the cleaning tank 2. However, the fan type, installation location, etc. are particularly limited as long as it has the function of the blower. Is not to be done. As shown in FIG. 1, the blower 3 includes an axial fan as a rotating body 4 and an electric motor 5. The rotating body 4 is formed of a resin molded product integrally formed by a boss portion 41 and a blade portion 42 at the center, and a pilot hole 41 a is provided at the center of the boss portion 41. On the outside of the electric motor 5, a rotating shaft 6 that is a drive shaft protrudes outward from one side of the electric motor 5.

  In the case where the rotating body 4 is installed as an air cooling fan for the electric motor 5, there is a rotating shaft 6 protruding from both sides of the electric motor 5 (not shown). A rotating body consisting of an air cooling fan is attached to and fixed to the other rotating shaft. A tap screw portion 61 and a step portion 62 formed with a shaft diameter larger than that of the tap screw portion 61 are provided at the distal end portion of the rotating shaft 6. On the other hand, the diameter of the pilot hole 41 a of the boss portion 41 is formed to a size adapted to the diameter of the tap screw portion 61. At the time of assembly, as will be described in detail later, the tap screw portion 61 of the rotating shaft 6 is screwed into the pilot hole 41a of the rotating body 4 disposed coaxially with the axis θ, and the end surface 41b of the boss portion 41 of the rotating body 4 is inserted. Is seated on the stepped portion 62 of the rotating shaft 6 and fastened with a predetermined torque.

  Next, the structure for fixing the rotating body 4 and the rotating shaft 6 configured as described above will be described based on the fastening principle between the rotating body 4 and the rotating shaft 6 during the operation of the blower 3. Since the fastening strength between the rotating body 4 and the rotating shaft 6 is reduced to the fastening strength of the tap screw portion 61 with respect to the resin boss portion 41, these will be described first. The relationship between the tightening amount of the tap screw 61 and the required tightening torque with respect to the resin boss 41 is a curve shown in FIG. When the tap screw portion 61 starts to be fastened to the resin boss portion 41, the torque gradually increases and then gradually increases. Thereafter, the stepped portion 62 corresponding to the end face 41b of the resin boss portion 41 and the screw head of the tap screw portion 61 comes into contact (sitting), and the torque suddenly increases at the portion indicated by point A in FIG. 2 breaks (breaks) the boss 41 at the position indicated by point B in FIG.

  Here, the tightening torque at point A in the figure is called seating torque, and the tightening torque at point B in the figure is called breaking torque. From this torque characteristic, an appropriate tightening torque when the tap screw 61 is tightened to the resin boss 41 is calculated. Further, the tap screw portion 61 starts to loosen at a torque value (referred to as a loosening torque) that is not less than the seating torque and not more than the proper tightening torque in the vicinity of the seating torque. In other words, a resin boss is used when tightening or rotating in the loosening direction with a rotational torque less than the breaking torque in the tightening rotation direction and with a rotational torque less than the seating torque in the loosening rotation direction. It can be understood that the fastening state is maintained without causing breakage and loosening of the portion 41.

  Based on the above, the fixed state of the rotating body 4 and the rotating shaft 6 will be described. The preceding seating torque corresponds to the tightening torque when the stepped portion 62 of the rotating shaft 6 is seated (contacted) on the end surface 41b of the rotating body 4, and the breaking torque is when the boss portion 41 of the rotating body 4 breaks. It corresponds to the tightening torque. Moreover, the design of the rated torque of the electric motor 5 needs to be a sufficiently large value with respect to the reaction moment that the rotating body 4 receives during the operation of the blower 3. Accordingly, in the case of the electric motor 5 for the blower 3 that can realize the function only by rotation in one direction, the proper tightening torque of the boss portion 41 is set in the vicinity of the rated torque of the electric motor 5, and the breaking torque of the boss portion 41 is set. What is necessary is just to design so as to be equal to or higher than the instantaneous maximum generated torque of the electric motor 5. On the other hand, in the case of the motor 5 or the like that rotates in both directions, the loosening torque is larger than the seating torque by designing the seating torque of the boss portion 41 to be equal to or greater than the continuous maximum generated torque of the motor 5. Therefore, no looseness occurs even in rotation in both directions.

  Here, the instantaneous maximum generated torque is torque generated at the time of the instantaneous maximum armature current, and the continuous maximum generated torque is the maximum value of the output torque in the continuous region. The instantaneous maximum armature current is the maximum current that can flow through the armature when the motor is cold or hot, and is limited by the demagnetization characteristics of the magnet, the armature reaction, and the temperature rise limit of each part. is there. The continuous region is a range of torque and rotational speed at which the temperature rise value of each part of the electric motor does not exceed the temperature rise limit when continuous operation is performed below the limit rotational speed.

FIG. 3 shows only the rotating body 4 and the rotating shaft 6 extracted during the operation of the blower 3. In the figure, the mark surrounded by ○ is the direction from the back to the front of the paper, and the × mark is ○ Each of the marks enclosed in (1) represents the direction from the front to the back of the page, and the rotation direction of the rotating object is represented by these two marks. The tap screw portion 61 is a right-hand screw.
When the blower 3 is in a stopped state, since both the rotating body 4 and the rotating shaft 6 are stopped, the torque generated between them is zero and neither tightens nor loosens. On the other hand, immediately after the blower 3 is started, the rotating shaft 6 starts to rotate clockwise as viewed from the direction of the arrow C in the figure. However, since the rotating body 4 increases the reaction moment received by the blade portion 42 with the rotation, the rotating shaft 6 rotates. Attempts to rotate at a rotational speed slower than 6 (upper side in FIG. 3). That is, when viewed from the rotating body 4, the rotational torque generated by the electric motor 5 acts on the boss portion 41 of the rotating body 4 that is stopped in the direction in which the tap screw portion 61 is tightened (lower side in FIG. 3).

However, as described above, since the breaking torque of the boss portion 41 is set to be equal to or higher than the instantaneous maximum generated torque of the electric motor 5, the boss portion 41 is not broken. As a result, the rotating body 4 rotates in synchronism with the rotation of the rotating shaft 6 without breaking, and when viewed from the rotating body 4, the rotating body 4 and the rotating shaft 6 are neither tightened nor loosened.
Further, when the blower 3 is just before stopping, the reaction moment acting on the blade portion 42 of the rotating body 4 decreases as the rotating speed of the rotating shaft 6 decreases, so that the rotating body 4 and the rotating shaft 6 are loosely tightened. If not.
From the above, the blower 3 is tightened only at the start, but since the instantaneous maximum generated torque value of the electric motor 5 is set to be equal to or less than the rupture torque of the boss portion 41, the fastening method prevents the rotation and the retaining. The fixed structure is applied.

On the other hand, the reverse rotation of the electric motor 5 can also be applied to fastening that rotates in both directions by setting the seating torque of the boss portion 41 to be equal to or greater than the continuous maximum generated torque of the electric motor 5 or the like. Further, during the operation of the blower 3, since a thrust force due to a pressure gradient or an impact force due to vibration is applied to the fastening portion, it has been conventionally necessary to perform a test using an actual device. However, according to the fixing structure of the first embodiment, the pullout strength and vibration resistance between a simple resin boss and a tap screw may be evaluated without using the actual blower 3.
Needless to say, if the direction of rotation of the electric motor 5 in only one direction is opposite to that described above, the tap screw 61 is left-handed.

  Next, an assembly method in which the rotating body 4 is screwed into the tap screw portion 61 of the rotating shaft 6 and fixed using the assembly jig illustrated in FIG. 4 will be described. The assembly is basically the same as when the screw is tightened with an electric screwdriver. As shown in FIG. 4A, the assembly jig includes an outer box 7 having at least one surface opened to accommodate the rotating body 4, and a rotating body standing from the center bottom of the outer box 7 toward the opening. 4 bosses 41 are held so as to be movable in the vertical direction in the figure along the axis, and the guides 8 that prevent the blades 42 from rotating, and the bosses 41 accommodated in the center of the guides 8 are shown in the figure. The elastic body 9 that holds the lower end portion and the lid 5 that closes the opening of the outer box 7 are fixed and held at a predetermined portion, and the tap screw portion 61 of the rotary shaft 6 is held at the bottom of the figure when held. 4, when the shaft is attached to the opening of the outer box 7, the axis of the tap screw 61 and the boss 41 are coaxial, and the tip of the tap screw 61 is connected to the boss 41 as shown in FIG. The pressing member 10 is pressed down against the elastic body 9. At the time of assembly, the electric motor 5 is driven by a drive circuit 11 with a torque limiter.

  First, as shown in FIG. 4A, the rotating body 4 is inserted into the outer box 7 while being held by the guide 8 and the elastic body 9 so that the open surface of the outer box 7 is normal outward, and is not shown. The pressing member 10 fixed by the fixing means is pressed downward in the figure. In this state, the electric motor 5 is installed at a predetermined position of the pressing member 10 from the outside of the open surface of the outer box 7. Accordingly, as shown in FIG. 4B, the rotating body 4 is pushed down by the rotating shaft 6 of the electric motor 5 and moved toward the bottom of the outer box 7. The electric motor 5 is fixed to the outer box 7 via the pressing member 10 by a fixing method (not shown). Next, the drive circuit 11 with a torque limiter is connected to the electric motor 5, and the rotating shaft 6 of the electric motor 5 is rotated so that the rotating body 4 pressed against the rotating shaft 6 is tapped on the boss portion 41 by the tap screw portion 61. As shown in FIG. 4C, the electric motor 5 is approached. By continuing the rotation, the end surface 41b of the boss 41 is brought into contact with and seated on the stepped portion 62 of the rotating shaft 6 as shown in FIG. 4D, and the fastening is completed with an appropriate tightening torque.

As described above, according to the first embodiment, the minimum configuration of the rotating body 4 having the boss portion 41 with the prepared hole 41a and the rotating shaft 6 provided with the stepped portion 62 and the tap screw portion 61 at the tip portion is provided. Since fastening can be realized with elements, the number of parts can be reduced and the structure can be simplified and inexpensive. In addition, since the fixing structure uses plastic deformation instead of elastic deformation, it is difficult to be affected by stress relaxation, and high-reliability fixing can be realized, and dimensional control of the diameter of the pilot hole 41a is relaxed, and molding is performed. Mold costs and maintenance costs can be reduced. Furthermore, tap screw fastening strength data can be used, and the reliability evaluation test can be shortened.
Further, the function is realized by the rotation of the rotating shaft 6 in only one direction, the proper tightening torque of the boss portion 41 is set near the rated torque of the electric motor 5, and the breaking torque of the boss portion 41 is the instantaneous maximum generated torque of the electric motor 5. By designing the boss portion to the same degree or more, it is possible to provide a fixing structure having sufficient strength even with a thin rotating shaft for a one-way rotating motor or the like.

Further, the rotating shaft 6 of the electric motor 5 realizes the function by rotating in both directions, the seating torque of the boss part 41 is equal to or higher than the continuous maximum generated torque of the electric motor 5, and the proper tightening torque of the boss part 41 is set to the electric motor. By designing the boss part with the instantaneous maximum generated torque of 5, it becomes possible to always use the torque screw below the instantaneous maximum generated torque in the tightening rotation direction of the tap screw part 61, ie, the tap screw part. A highly reliable fastening structure that can be used in a torque range equal to or less than the continuous maximum generated torque in the loose rotation direction of 61 can be provided.
Furthermore, the rotating body 4 and the rotating shaft 6 can be assembled by the fastening operation of the tap screw portion 61 that fixes the rotating body 4 to a simple assembly jig and operates the electric motor 5 to rotate the rotating shaft 6. Assembling can be performed in the same manner as described above, and the assemblability can be improved, and at the same time, the operation of the motor can be confirmed.

Embodiment 2. FIG.
6 and 7 are diagrams for explaining a structure for fixing a rotating body and a rotating shaft according to Embodiment 2 of the present invention. FIG. 6 is a partially sectional assembly view, and FIG. In the figure, the rotary shaft 6 is formed with a stepped portion 62, a tap screw portion 61, a stepped portion 63, and a screw portion 64 made of a tap screw or a normal screw in the axial end direction. In addition, the direction of the screw of the tap screw part 61 and the screw part 64 is reversed. On the other hand, the central portion of the boss portion 41 of the rotating body 4 has an inner diameter suitable for the tap screw portion 61 and is approximately half the length of the boss portion 41 and a diameter adjacent to the lower hole 41a. An enlarged step portion 41c and a fixed body accommodating portion 41d that receives the nut-like fixed body 12 that is screwed or screwed into the screw portion 64 are formed. The screw part 64, the step part 41c, and the fixed body 12 constitute the fastening means 13. Other reference numerals are the same as those in the first embodiment.

  In the second embodiment configured as described above, the pilot hole 41a portion of the rotating body 4 is screwed into the tap screw portion 61 along the axis θ as in the first embodiment, and the end surface 41b is seated on the stepped portion 62. Let them conclude. The fixed body 12 is screwed into the screw portion 64, the fixed body 12 is brought into contact with the stepped portion 41 c of the rotating body 4 and tightened, and the rotating body 4 is fastened to the rotating shaft 6. Here, the fixing body 12 can be fastened using a resin material having a boss if the screw portion 64 is a tap screw, and using a normal nut or the like if the screw portion 64 is a general screw.

  Next, the fastening principle of this fixing structure will be described with reference to FIG. Here, the tap screw portion 61 is a right-hand screw, and the screw portion 64 is a left-hand screw. When the rotating shaft 6 rotates clockwise as viewed from the direction of arrow D in the figure, as described in the first embodiment, the rotating body 4 does not rotate in the loosening direction and is not shown. Here, although the rotation is in a loosening direction with respect to the fixed body 12, the counter-moment acting on the fixed body 12 due to the rotation is almost zero. 4 and rotate in synchronization with the rotating shaft 6.

  On the other hand, consider the case of rotating counterclockwise as viewed from the arrow D in the figure. When there is only one tap screw portion 61 described in the first embodiment, it is necessary that the proper tightening torque of the boss portion 41 of the rotating body 4 be close to the instantaneous maximum generated torque of the electric motor 5. Here, since the appropriate tightening torque is sufficiently smaller than the breaking torque for the same boss, the screw length of the tap screw portion 61 is increased in the first embodiment. However, as shown in FIGS. 6 and 7, the size can be reduced by adding a fixed body 12 sandwiched between the rotating body 4 and fastened to the rotating shaft 6. The rotating body 4 tries to rotate at a slow speed with respect to the counterclockwise rotation of the rotating shaft 6. At this time, the frictional force acts not only between the rotating body 4 and the rotating shaft 6 but also between the rotating body 4 and the fixed body 12 (E portion indicated by a thick line in the figure) counterclockwise.

  Due to the counterclockwise frictional force, the fixed body 12 is not loosened and is further tightened to the rotating shaft 6. For this reason, the rotating body 4 is in a state of being tightened and tightened more firmly by the stepped portion 62 of the rotating shaft 6 and the fixed body 12. As a result, it is not necessary that the proper tightening torque of the boss portion 41 be close to the instantaneous maximum generated torque of the electric motor 5, and the breaking torque that is sufficiently larger than the seating torque for the same boss is about the same as the instantaneous maximum generated torque. The proper tightening torque may be in the vicinity of the rated torque of the rotating shaft 6. Here, since the seating torque and the breaking torque are substantially proportional to the screw length of the tap screw portion 61, the screw length can be shortened, and the rotating body 4 is synchronized with the rotating shaft 6 and the fixed body 12. Thus, it will rotate counterclockwise.

  As described above, according to the second embodiment, the two stepped portions 62 and 63, the tap screw portion 61, and the screw portion 64 are formed at the tip portion of the rotating shaft 6, and are fastened by the added fixing body 12, and the boss The proper tightening torque of the portion 41 is set to the vicinity of the rated torque of the electric motor 5, the breaking torque of the boss portion 41 is set to be equal to or higher than the instantaneous maximum generated torque of the electric motor 5, and the breaking torque of the fixed body 12 is the same as the rated torque of the electric motor 5. By setting it to about or more, the screw length is greatly shortened, and the size in the direction of the rotation axis can be reduced. The present invention can also be applied to a rotating shaft 6 such as an electric motor 5 that rotates in both directions.

Embodiment 3 FIG.
FIG. 8 is a partially sectional assembly view showing a structure for fixing a rotating body and a rotating shaft according to Embodiment 3 of the present invention. The third embodiment corresponds to a modification of the second embodiment. From the shaft end portion 65 side of the rotary shaft 6, the screw screw 61 is coaxial with the tap screw portion 61 and has a smaller diameter than the tap screw portion 61, and the screwing direction of the screw is a tap screw. A female screw 66 opposite to the portion 61 is screwed, and a fixing screw 14 having a screw portion 14 a that is screwed into the female screw 66 is used as the fixing means 13. Others are the same as those in the second embodiment, and the description thereof is omitted.

  Needless to say, the third embodiment configured as described above operates in the same manner as in the second embodiment, and the same effect can be obtained. In the third embodiment, since both the length of the tap screw portion 61 and the length of the fixing screw 14 can be increased, the allowable torque is increased for the same boss portion 41 length. Alternatively, the length of the boss portion 41 can be reduced for the same allowable torque.

  By the way, in the said Embodiment 1-3, although the case where the rotary body 4 was an axial flow fan was demonstrated, it is not limited to this from the first, For example, other fans, such as a sirocco fan and a turbo fan, Alternatively, for example, a rotating body other than a fan used by being fixed to a rotating shaft, such as a gear, a pulley, a cam, a lever, or a disk, may be used, and the material is not limited to resin. Although the description has been given of the case where the rotary shaft 6 is the drive shaft of the electric motor 5 used as a drive source, it is needless to say that the same effect can be obtained by using the rotary shaft of another rotary drive source or the driven rotary shaft. Furthermore, the target fluid of the impeller is assumed to be air, and the blower and the air cooling fan have been described. However, the same effect can be obtained even when applied to a fixed structure of an impeller such as a liquid pump having a large rated torque of the rotating shaft. It goes without saying that it is obtained.

FIG. 3 is a partial cross-sectional assembly view showing a resin axial fan as a rotating body and a drive shaft of an electric motor as a rotating shaft in a structure for fixing the rotating body and the rotating shaft according to Embodiment 1 of the present invention. The characteristic view measured about the relationship between the tightening amount of the tap screw with respect to the boss | hub of the axial fan shown in FIG. 1, and required tightening torque. Operation | movement explanatory drawing when rotating what fixed the rotary body and rotating shaft shown in FIG. FIG. 2 is an explanatory view showing an example of an assembling jig used when fixing the rotating body and the rotating shaft shown in FIG. The principal part sectional drawing which shows the whole structure at the time of using what fixed the rotary body and rotating shaft shown in FIG. 1 for a dishwasher. The partial cross-section assembly figure explaining the fixation structure of the rotary body and rotating shaft by Embodiment 2 of this invention. Operation | movement explanatory drawing of the fixing structure of the rotary body shown in FIG. 6, and a rotating shaft. The partial cross section assembly figure which shows the fixed structure of the rotary body and rotating shaft by Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dishwasher, 2 Washing tank, 3 Blower, 4 Rotor (Axial fan), 41 Boss part, 41a Pilot hole, 41b Bottom part, 41c Step part, 41d Fixed body accommodating part, 42 Blade part, 5 Electric motor, 6 Rotating shaft (drive shaft), 61 Tap screw portion, 62 Step portion, 63 Step portion, 64 Screw portion, 65 Shaft end portion, 66 Female screw, 7 Outer box, 8 Guide, 9 Elastic body, 10 Holding member, 11 Torque limiter Drive circuit, 12 fixed body, 13 fastening means, 14 fixing screw, 14a screw part.

Claims (9)

  A tap screw portion and a stepped portion are provided in a predetermined portion of the rotating shaft, a boss portion having a pilot hole with an inner diameter matching the tap screw portion is provided in the rotating body, and the tap screw portion of the rotating shaft is screwed into the pilot hole of the rotating body. A structure for fixing a rotating body and a rotating shaft, wherein a boss portion of the rotating body is rarely seated on the stepped portion.   The rotating shaft is composed of a drive shaft that rotates in one direction, and the appropriate tightening torque of the boss portion when screwed is in the vicinity of the rated torque of the rotating shaft, and the breaking torque of the boss portion is the instantaneous maximum of the rotating shaft. The structure for fixing a rotating body and a rotating shaft according to claim 1, wherein the fixing structure is equal to or greater than the generated torque.   The rotating shaft is composed of a drive shaft that is rotated in both directions, and the rotating body has a tightening torque when the boss portion is seated on the stepped portion is equal to or more than the continuous maximum generated torque of the rotating shaft. In addition, the proper tightening torque is fastened in the vicinity of the instantaneous maximum generated torque of the rotary shaft, and the rotary shaft is driven within the torque range below the continuous maximum generated torque in the loosening rotation direction of the tap screw portion. The structure for fixing a rotating body and a rotating shaft according to claim 1.   The rotating shaft is composed of a drive shaft that is rotated in both directions, and is provided with fastening means for fixing the boss portion of the rotating body in the direction of the stepped portion on the opposite side of the stepped portion with respect to the tap screw portion. The structure for fixing a rotating body and a rotating shaft according to claim 1.   The fastening means includes a screw portion that is provided adjacent to the tap screw portion at the shaft end portion of the rotating shaft and has a smaller diameter than the tap screw portion, and a screw direction opposite to the tap screw portion. 5. The structure for fixing a rotating body and a rotating shaft according to claim 4, comprising a fixing body for fixing a boss portion of the rotating body screwed or screwed to the step to the stepped portion.   The fastening means includes a female screw provided at an axial center of the tap screw portion of the rotating shaft and having a diameter smaller than that of the tap screw portion, and a screwing direction opposite to the tap screw portion, and a screw threaded on the female screw. The fixing structure for a rotating body and a rotating shaft according to claim 4, comprising a fixing screw for fixing the boss portion of the rotating body to the stepped portion.   The rotation shaft has an appropriate tightening torque between the boss portion and the fastening means in the vicinity of a rated torque of the rotation shaft, and a breaking torque is an instantaneous maximum generation torque of the rotation shaft. The structure for fixing a rotating body and a rotating shaft according to any one of claims 4 to 6.   8. The structure for fixing a rotating body and a rotating shaft according to claim 1, wherein the rotating shaft comprises a drive shaft of an electric motor. The structure for fixing a rotating body and a rotating shaft according to any one of claims 1 to 8, wherein the rotating body is made of a resin molded body.

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