JP6518817B2 - Motor and motor structure - Google Patents

Description

The present invention relates to motors and motor structures.

  As a method of fixing a press-fit object such as a gear to the motor shaft, a hole for inserting the motor shaft is provided in the press-fit object, and processing is performed so that the inner diameter of the hole of the press-fit object is slightly smaller than the outer diameter of the motor shaft. There is a method of press-fitting and fixing the motor shaft in the hole of the object to be press-fit.

  The force required to press the motor shaft into the press-fit object is approximately the value obtained by multiplying the press-fit interference ((the outer diameter of the motor shaft)-(the inner diameter of the press-fit object)) by the press-fit length. Proportional to If the force required for press-fitting is larger than the allowable compression stress of the motor shaft, the motor shaft may be buckled when the motor shaft is press-fit into the press-fit object. By shortening the press-fit length, the force required for press-fit can be reduced so as not to cause the motor shaft to buckle. However, if the press-fit length is shortened, when the motor shaft is press-fit into the press-fit object, the shaft of the motor shaft and the shaft of the press-fit object easily tilt, and the press-fit object is fixed to the motor shaft with high accuracy. Is not easy.

  On the other hand, when the press-fit length is increased, the press-fit object can be fixed to the motor shaft with high accuracy. When the press-in length is increased, it is necessary to reduce the upper limit of the press-in interference so that the force required for the press-in becomes smaller than the allowable compression stress of the motor shaft. The tolerance of the outer diameter of the motor shaft and the inner diameter of the hole of the object to be pressed can be designed in design so that the upper limit of the press fit interference becomes smaller. However, it is difficult to machine the outer diameter of the motor shaft and the inner diameter of the object to be press-fit as designed in an actual manufacturing process. For this reason, it is necessary to make adjustments in the manufacturing process such as layering the machined motor shaft and the press-in object so that the force required for press-fitting becomes smaller than the allowable compression stress of the motor shaft. Therefore, in order to prevent the motor shaft from buckling, there is a need for a motor shaft that can be pressed into a press-fit object with a small force.

  Patent Document 1 discloses a serrated motor shaft that can be pressed into a female part with a small force.

JP 2012-257389 A

  However, even with the motor shaft of Patent Document 1, the force required for press-fitting increases in proportion to the press-fitting length. For this reason, if the press-in length is increased, adjustments in the manufacturing process such as stratification of the machined motor shaft and female parts are required so that the force required for press-in becomes smaller than the allowable compression stress of the motor shaft. Become.

The present invention has been made in view of the circumstances as described above, and an object thereof is to provide a motor and a motor structure having a motor shaft that can be input pressure with a small force.

To achieve the above object, the motor according to the first aspect of the present invention,
Equipped with a shaft with a press-fit surface,
A first annular projection group and a second annular projection group are formed on the press-fit surface of the shaft,
In the axial direction, the first annular projection group is spaced apart from the second annular projection group,
In the axial direction, the first spacing ring-shaped projection adjacent the annular projection group, and spacing of be that ring-like projections adjacent in the second annular projection group, the said the first annular protrusion first Less than the distance between the two annular projections.

It said first annular projection group, may that have a two first annular protrusion.

The second annular projection group, may that have a two second annular protrusion.

An outer diameter of said first annular projection group outer diameter as the second annular projection group of the size contemplated than the outer diameter of the shaft between the said first annular projection group and the second annular projection group Good.

The outer diameter of the second annular projection group may be larger than the outer diameter of the first annular projection group .

In the axial direction, the second annular projection group, may that be formed on the rear end side of the first annular projection group.

And a magnet provided on the front carboxymethyl Yafuto,
And coils,
It is good to have

  In the axial direction, the first annular projection group is formed on the tip side of the press-fit surface of the shaft,
  In the axial direction, the second annular projection group may be formed on the rear end side of the press-fit surface of the shaft.

Furthermore, to achieve the above object, a motor structure according to a second aspect of the present invention is:
Equipped with a shaft with a press-fit surface,
A first annular projection group and a second annular projection group are formed on the press-fit surface of the shaft,
In the axial direction, the first annular projection group is spaced apart from the second annular projection group,
In the axial direction, the distance between the adjacent annular projections in the first annular projection group and the distance between the adjacent annular projections in the second annular projection group are the first annular projection group and the second annular projection. Less than the interval with the group.

According to the present invention, it is possible to provide a motor and a motor structure having a motor shaft that can be input pressure with a small force.

1 is a cross-sectional view showing a motor structure according to a first embodiment of the present invention. (A) is a side view of a motor shaft according to a first embodiment of the present invention, and (B) is a front view of a motor shaft according to the first embodiment of the present invention. (A) is a front view showing a press-fit object into which a motor shaft according to a first embodiment of the present invention is press-fit, and (B) is a motor shaft according to the first embodiment of the present invention It is an AA 'cross section showing a press-fit object into which the It is a figure which shows the relationship of the load at the time of press-fitting the motor shaft which concerns on the 1st Embodiment of this invention to a press-fit object, and a pressing amount. It is a figure which shows the relationship of the load at the time of press-fitting the conventional motor shaft to a to-be-injected object, and the amount of pressing-in. (A) is a side view of a motor shaft according to a second embodiment of the present invention, and (B) is a front view of a motor shaft according to a second embodiment of the present invention. It is sectional drawing which shows the state which pressingly injected the motor shaft which concerns on the 2nd Embodiment of this invention in a to-be-press-fit object. It is a figure which shows the relationship of the load at the time of press-fitting the motor shaft which concerns on the 2nd Embodiment of this invention to a press-fit object, and a pressing amount. It is sectional drawing which shows the state which press-fitd the motor shaft which concerns on the 1st modification of this invention to a magnet. It is a side view of a motor shaft concerning the 2nd modification of the present invention. It is sectional drawing which shows the state which press-fits the conventional motor shaft in the to-be-pressed object.

  Hereinafter, a motor shaft, a motor and a motor structure according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

First Embodiment
FIG. 1 is a cross-sectional view of a motor structure according to a first embodiment of the present invention. As shown in FIG. 1, a motor structure 100 includes a motor 101 including a motor shaft 1 and a press-fit object 4. The motor 101 includes, in addition to the motor shaft 1, a magnet 12 provided on the motor shaft 1, a pair of bearings 13a and 13b for rotatably supporting the motor shaft 1, a coil 14, and a case for accommodating the above respective portions. And 11.

  The case 11 is a rectangular solid hollow member. On the left and right sides of the case 11 in FIG. 1, circular openings penetrating in the axial direction are respectively formed. The motor shaft 1 is rotatably supported by a pair of bearings 13a and 13b in a state where the tip end portion protrudes outward from the right opening.

  The magnet 12 is a cylindrical member having a through hole through which the motor shaft 1 passes. The magnet 12 is fixed to the motor shaft 1 inserted into the through hole.

  The coil 14 is arranged to surround the magnet 12. The coil 14 rotates the motor shaft 1 together with the magnet 12 by electromagnetic interaction with the magnet 12.

  A press-fit object 4 is fixed to the end of the motor shaft 1. The motor shaft 1 has an annular protrusion 2 at a portion for fixing the object 4 to be press-fitted, and is rotatably supported by bearings 13 a and 13 b and provided in the case 11. A coil 14 for generating a magnetic field is fixed to the case 11.

  When a current is supplied to the motor 101, the coil 14 generates a rotating magnetic field. The magnet 12 receives a force by the rotating magnetic field, and the motor shaft 1 rotates. Next, the motor shaft 1 of the first embodiment will be described.

  As shown in FIG. 2, the motor shaft 1 of the first embodiment is formed at a cylindrical shaft main body 10 of diameter a and at four places in the axial direction, and when the motor shaft 1 is press-fit into the press-fit object 4 And an annular protrusion 2 in contact with the inner circumferential surface of the press-in hole 5.

  The annular projection 2 is a projection that protrudes outward in the radial direction of the shaft main body 10 and goes around the outer peripheral surface. Two first annular projections 2a are formed in the vicinity of the axial direction leading end of the press-fit surface of the press-fit shaft body 10 and the press-fit hole 5. The two first annular projections 2a constitute a first annular projection group 3a. The distance between adjacent first annular projections 2a is X. Two second annular projections 2 b are formed adjacent to the rear end in the axial direction of the press-fitting surface of the press-fit shaft body 10 and the press-fitting hole 5. The two second annular projections 2b constitute a second annular projection group 3b. The distance between the adjacent second annular projections 2 b is a distance X. The first annular projection group 3a and the second annular projection group 3b are formed to be separated in the axial direction. The distance between the first annular projection group 3 a and the second annular projection 3 b is an interval Y larger than the interval X. The outer diameter of the first annular projection 2a is an outer diameter b, and the outer diameter of the second annular projection 2b is an outer diameter c larger than the outer diameter b. The axial length of the first annular protrusion 2a and the second annular protrusion 2b is a length d.

  As shown in FIG. 3, the press-fit object 4 has a press-in length of length L and is formed in the vicinity of the inlet side where the motor shaft 1 is press-in, and the second annular projection 2b bites into the inner circumferential surface While the first annular projection 2a bites into the inner circumferential surface at a deeper side than the first press-in hole 5a of diameter C and the first press-in hole 5a, And a press-fit hole 5 composed of two press-fit holes 5b. The press-fit object 4 is a component that is fixed to the motor shaft 1 and rotates with the motor shaft 1, and is specifically a gear or the like. The axial length of the first press-in hole 5a is E. The length L is longer than the interval Y. The diameter B is slightly smaller than the outer diameter b of the annular projection 2. The press-fit interference is represented by an outer diameter b-diameter B. Assuming that the diameter B is 1 so that the press-fit interference is an appropriate value, the outer diameter b is preferably 1.001 to 1.020. The diameter C is slightly smaller than the outer diameter c of the annular projection 2. The press-fit interference is represented by an outer diameter c-diameter C, and assuming that the diameter C is 1 so that the press-fit interference becomes an appropriate value, the outer diameter c is preferably 1.001 to 1.020 . Also, the diameter B is greater than or approximately the same as the diameter a. The diameter B is a diameter a so that the motor shaft 1 and the press-fit object 4 can be prevented from idling when the portion other than the annular protrusion 2 of the motor shaft 1 contacts the inner peripheral surface of the press-fit hole 5. It is preferable that it is substantially the same as Further, in order to reduce the force required for press-fitting, the diameter C is preferably larger than the outer diameter b.

  Next, a method of press-fitting the motor shaft 1 into the press-fit object 4 will be described.

  The workpiece 4 is fixed using a jig or the like. Alignment is performed so that the axis of the press-in hole 5 of the fixed press-fit object 4 and the axis of the motor shaft 1 are coaxial. The motor shaft 1 is moved in the axial direction, and the motor shaft 1 is pushed into the press-in hole 5 from the side of the first press-in hole 5 a. When the motor shaft 1 is pushed to a predetermined position, fixing of the motor shaft 1 and the press-fit object 4 is completed.

  Next, the relationship between the pressing amount when the motor shaft 1 is press-fitted into the press-fit object 4 and the force (load for pressing) necessary for the press-fitting will be described. The distance Y is shorter than the axial length E of the first press-in hole 5a. FIG. 4 is a graph showing the relationship between the pressing amount and the load by which the motor shaft 1 is pressed into the press-in hole 5 in an arbitrary unit. When the motor shaft 1 is pushed into the press-in hole 5, the second annular projection 2b on the tip side of the second annular projection group 3b contacts the end of the first press-in hole 5a, and the load for pushing in increases. The load peaks while the end of the first press-in hole 5a passes through the second annular projection 2b on the tip side. When the load is further reduced, the load decreases, but when the end of the first press-in hole 5a starts to contact the second annular projection 2b on the rear end side of the second annular projection group 3b, the load increases again, and the first press-in The load peaks when the end of the hole 5a passes through the second annular projection 2b on the rear end side. After that, the load to push in becomes smaller. Next, when the motor shaft 1 is further pushed into the press-in hole 5, the first annular projection 2a on the tip side of the first annular projection group 3a comes in contact with the end of the second press-in hole 5b, and the load for pushing in Becomes larger. The load peaks while the end of the second press-in hole 5b passes through the first annular projection 2a on the tip side. When the load is further reduced, the load decreases but the load increases again when the end of the second press-in hole 5b starts to contact the first annular projection 2a on the rear end side of the first annular projection group 3a. The load peaks when the end of the hole 5b passes through the first annular projection 2a on the rear end side. Then, if it pushes in further, the load for pushing in will become small. The width of the second two peaks and the width of the second two peaks are the same as the interval X. Also, the widths of the first two peaks and the second two peaks are smaller than the interval Y.

  On the other hand, the relationship between the pressing amount and the load when press-fitting the conventional motor shaft S without the annular projection 2 shown in FIG. 11 into the press-fit object 4 will be described. The graph which represented the relationship between the amount of indentations which pushes motor shaft S into the to-be-pressed object 4, and load in arbitrary units is shown in FIG. When the front end of the motor shaft S and the end of the press-in hole 5 begin to come in contact, the load increases and forms a peak. Although the load once decreases, it increases linearly thereafter, and when the motor shaft S is completely pushed into the press-in hole 5, the load is maximized. When the motor shaft S is further pressed into the press-fit object 4 for press-fitting, the maximum load is required. Further, when the conventional motor shaft S is pushed into the press-fit object 4, the pushing distance where the load is required is the length L.

  Next, the force P necessary for press-fitting the motor shaft 1 into the press-fit object 4 will be described in comparison with the force p required for press-fitting the motor shaft S into the press-fit object 4. The force required for press-fitting is approximately proportional to (press-in interference) × (axial length at which the motor shaft and the press-fit object contact). From this, the force P necessary for press-fitting the motor shaft 1 into the press-fit object 4 is (press-fit interference) × (axial length d × 4 at which the press-fit object 4 contacts the motor shaft 1) (Proportional to the number of annular projections 2)). On the other hand, the force p required to press the motor shaft S into the press-fit object 4 is approximately proportional to (press-fit interference) × (axial length L of the press-fit hole 5 of the press-fit object 4). Do. The outer diameter of the motor shaft S is e, the outer diameter e is slightly larger than the diameter B, and the press-fit interference is represented by an outer diameter e-diameter B.

  As described above, according to the first embodiment, by forming the annular projection 2 in contact with the inner peripheral surface of the press-fit hole 5 of the press-fit object 4 in the shaft main body 10, force required for press-fit Is larger for each annular projection 2 but smaller for portions other than the annular projection 2. Further, by setting the dimensions (Y and E) of the motor shaft 1 and the press-fit object 4 so that the timing of load generation at the time of press-fitting may be shifted, the pressing distance necessary for press-fitting can be shortened. Further, assuming that the force P necessary for press-fitting is the same as the press-fit interference outer diameter b-diameter B, the outer diameter c-diameter C and the outer diameter e-diameter B, the force necessary for press-fitting It is (length d × 4) / length L times p. Specifically, assuming that length d = length L / 40, the force P required for press-fitting is one tenth of the force p required for press-fitting. For this reason, the motor shaft 1 can be pressed into the press-fit object with a smaller load than the motor shaft S. That is, the maximum value of the load for pressing the motor shaft 1 shown in FIG. 4 into the press-fit object 4 is smaller than the maximum value of the load for pressing the motor shaft S shown in FIG. Also, the force P necessary for press-fitting can be adjusted by changing the length d, even if the press-in interference is the same. Further, assuming that the allowable compressive stress of the motor shaft 1 and the allowable compressive stress of the motor shaft S are the same, the upper limit of the press-in interference where the motor shaft 1 does not buckle is the press-in interference where the motor shaft S does not buckle The upper limit length L / (length d × 4) times. Specifically, assuming that the length d = the length L / 40, the upper limit of the press-in interference where the motor shaft 1 does not buckle is ten times the upper limit of the press-in interference where the motor shaft S does not buckle . As described above, by forming the annular projection 2 in the motor shaft 1, the upper limit of the press-in interference can be increased, and the burden of fitting such as layering in the manufacturing process can be reduced.

  The outer diameter of the first annular projection 2 a is the outer diameter b, and the outer diameter of the second annular projection 2 b is the outer diameter c larger than the outer diameter b. When press-fitting, the motor shaft 1 can be press-fit into the press-fit object 4 with a small force until the first press-in hole 5a and the second annular projection 2b contact with each other.

  Further, the annular projections 2 are formed adjacent to each other, and by forming the annular projection group 3, those having the tip of the projections scraped out have an effect of remaining in between the projections and increasing the number of annular projections 2. As a result, the protrusion of the annular protrusion 2 may be crushed or bite with the inner peripheral surface of the press-in hole 5 of the object 4 to be pressed-in, thereby increasing the fastening force. Further, since a plurality of annular projections 2 are provided in the axial direction of the shaft main body 10, it is possible to prevent the inclination of the axis of the motor shaft 1 and the axis of the object 4 to be press-fitted. Since the inclination of the axial direction of the press-fit object 4 can be prevented more if the space | interval Y is large, it is preferable to make the space | interval Y large. If the motor shaft 1 is made of a material having a Vickers hardness lower than the Vickers hardness of the object 4 to be pressed, the annular projection 2 is crushed and the inner circumferential surface of the press-in hole 5 of the object 4 to be pressed is scratched. It is fixed. For example, when the object 4 to be pressed is a sintered metal or the like, the material of the shaft is preferably stainless steel SUS303 or the like.

  On the other hand, in the motor shaft S not having the annular projection 2, the force required for press-fitting is linearly increased and does not decrease halfway, and the pressing distance required for press-fitting is the length L, It can not be shortened.

Second Embodiment
The motor shaft 1 according to the second embodiment, as shown in FIG. 6, is formed at a cylindrical shaft body 10 with a diameter a and at two places in the axial direction, and pressing the motor shaft 1 into the press-fit object 4 And an annular protrusion 2 in contact with the inner peripheral surface of the press-in hole 5.

  The annular projection 2 is a projection that protrudes outward in the radial direction of the shaft main body 10 and goes around the outer peripheral surface. The first annular projection 2 a is formed in the vicinity of the axial direction leading end of the press-fit surface with the press-fit hole 5 of the shaft body 10 which is press-fitted. The second annular projection 2 b is formed in the vicinity of the rear end in the axial direction of the press-fit surface with the press-fit hole 5 of the shaft body 10 which is press-fitted. The outer diameter of the first annular projection 2a is an outer diameter b, and the axial length is a length d. The outer diameter of the second annular projection 2b is an outer diameter c, and the axial length is a length d. The axial distance between the first annular protrusion 2 a and the second annular protrusion 2 b is a distance Y.

  The press-in object 4 is the same as that of the first embodiment. The method of press-fitting the motor shaft 1 into the press-fit object 4 is the same as that of the first embodiment. The motor shaft 1 press-fit into the press-fit object 4 is shown in FIG.

  Next, the relationship between the pressing amount when the motor shaft 1 is press-fitted into the press-fit object 4 and the force (load for pressing) necessary for the press-fitting will be described. The distance Y is shorter than the axial length E of the first press-in hole 5a. The graph which represented the relationship between the amount of indentations which pushes motor shaft 1 into press fit hole 5, and load in arbitrary units is shown in FIG. When the motor shaft 1 is pushed into the press-in hole 5, the second annular projection 2b and the end of the first press-in hole 5a start to come into contact, the load for pushing in increases, and the end of the first press-in hole 5a The load peaks when passing through the two annular projections 2b. Thereafter, the load decreases, and the load increases when the end of the first annular projection 2a and the end of the second press-in hole 5b begin to contact, and the end of the second press-in hole 5b passes through the first annular projection 2a. The load peaks at the moment. After that, the load decreases. The width of the indentations of these two peaks is shorter than the interval Y.

  As described above, according to the second embodiment, by forming the annular projection 2 in contact with the inner peripheral surface of the press-fit hole 5 of the press-fit object 4 in the shaft main body 10, force required for press-fit Is larger for each annular projection 2 but smaller for portions other than the annular projection 2. On the other hand, in the motor shaft S which does not have the annular projection 2, the force required for press-fitting is linearly increased and does not decrease halfway. Further, assuming that the force P necessary for press-fitting the motor shaft 1 into the press-fit object 4 is the same as the motor shaft 1 of the first embodiment, assuming that the press-in interference is the same, the annular protrusion 2 is included. It can be smaller than the motor shaft S which is not provided. For this reason, the motor shaft 1 of the second embodiment is, similarly to the motor shaft 1 of the first embodiment, press-fit into the press-fit object 4 with a smaller load than the motor shaft S without the annular projection 2. can do. Further, the upper limit of the press-fit interference without the motor shaft 1 being buckled is the same as that of the motor shaft 1 of the first embodiment, the motor shaft 1 forms an annular projection 2 to increase the upper limit of the press-fit interference. It is possible to reduce the burden of grinding such as layering in the manufacturing process.

  Further, since a plurality of annular projections 2 are provided in the axial direction of the shaft main body 10, it is possible to prevent the inclination of the axis of the motor shaft 1 and the axis of the object 4 to be press-fitted. For this reason, the motor shaft 1 and the press-fit object 4 can be fixed with high accuracy. If the distance Y is large, the inclination in the axial direction can be further prevented, so the distance Y is preferably large. The outer diameter of the first annular projection 2 a is the outer diameter b, and the outer diameter of the second annular projection 2 b is the outer diameter c larger than the outer diameter b. When press-fitting, the motor shaft 1 can be press-fit into the press-fit object 4 with a small force until the first press-in hole 5a and the second annular projection 2b contact with each other. Further, the motor shaft 1 of the second embodiment is suitable in the case where a buckling deformation such as a thin shaft is concerned.

  If the motor shaft 1 is made of a material having a Vickers hardness lower than the Vickers hardness of the object 4 to be pressed, the annular projection 2 is crushed and the inner circumferential surface of the press-in hole 5 of the object 4 to be pressed is scratched. It is fixed. For example, when the object to be pressed is a sintered metal or the like, the material of the shaft is preferably stainless steel SUS303 or the like.

(Modification)
In the first and second embodiments, the case where the portion of the motor shaft 1 protruding from the case 11 is press-fit into the press-fit object 4 has been described, but the press-fit object 4 supports two shafts supporting the shaft. It may be located between the Further, as shown in FIG. 9, an annular projection 2 may be formed on the motor shaft 1 in the portion where the magnet 12 is inserted. When press-fitting the motor shaft 1 into the magnet 12, the outer diameter of the annular projection 2 on the tip end side of the motor shaft 1 is made smaller than the outer diameter of the annular projection 2 on the rear end side. After fitting, the inner diameter of the inlet of the metal sleeve 15 is made larger than the inner diameter of the rear side. In this case, when the motor shaft 1 is press-fitted to the metal sleeve 15, the same effect as that obtained when the motor shaft 1 is press-fitted to the press-fit object 4 can be obtained. Since a plurality of annular projections 2 are provided in the axial direction of the motor shaft 1, inclination of the axes of the motor shaft 1 and the magnet 12 can be prevented. Further, the press-fit object 4 may be a component which becomes a weight such as a tungsten flywheel or a component such as a metal hub which holds an impeller for a fan motor.

  In the first embodiment, the two annular projections 2 constitute the annular projection group 3, but three or more annular projections 2 may constitute the annular projection group 3. In the first embodiment, the two annular projection groups 3 are formed on the motor shaft 1, but three or more annular projection groups 3 may be formed on the motor shaft 1. In the second embodiment, the two annular projections 2 are formed on the motor shaft 1, but three or more annular projections 2 may be formed on the motor shaft 1.

  When the diameter e of the motor shaft S is small (6 mm or less), the motor shaft S tends to buckle particularly when the force required for press-fitting is large. In the motor shaft 1 according to the first and second embodiments, the force required for press-fitting can be reduced. Therefore, even when the diameter a of the motor shaft 1 is small (6 mm or less), the motor shaft 1 is It can prevent buckling.

  In the first and second embodiments, the annular projection 2 has been described to have a rectangular cross section of the projection, but as shown in FIG. 10, the annular projection 2 has an arched cross section of the projection. May be In this case, the motor shaft 1 and the press-fit object 4 are fixed by elastically deforming the top of the arch. In the first and second embodiments, the diameter b of the first annular projection 2a is smaller than the diameter c of the second annular projection 2b, but the diameter b may be the same as the diameter c. In this case, since the press-in holes 5 of the press-in object 4 can be made straight, the production of the press-in object 4 becomes easy.

  The present invention is capable of various embodiments and modifications without departing from the broad spirit and scope of the present invention. The embodiments described above are for explaining the present invention, and do not limit the scope of the present invention.

Reference Signs List 1 motor shaft 2 annular projection 2a first annular projection 2b second annular projection 3 annular projection group 3a first annular projection group 3b second annular projection group 4 press-fit object 5 press-in hole 5a first press-in hole 5b Second press-in hole 10 Shaft body 11 Case 12 Magnet 13a, 13b Bearing 14 Coil 15 Metal sleeve 100 Motor structure 101 Motor

Claims (9)

Equipped with a shaft with a press-fit surface,
A first annular projection group and a second annular projection group are formed on the press-fit surface of the shaft,
In the axial direction, the first annular projection group is spaced apart from the second annular projection group,
In the axial direction, the first spacing ring-shaped projection adjacent the annular projection group, and spacing of be that ring-like projections adjacent in the second annular projection group, the said the first annular protrusion group the interval smaller, motor and second annular projection group. Said first annular projection group is that having a two first annular projection, motor according to claim 1. The second annular projection group is that having a two second annular projection, motor according to claim 1 or 2. An outer diameter of said first annular projection group outside diameter and said second annular protrusion group is not larger than the outer diameter of the shaft between the said first annular projection group and the second annular projection group , motor according to any one of claims 1 to 3. The outer diameter of the second annular projection group, the first is greater than the outer diameter of the annular projection group, motor according to any one of claims 1 to 4. In the axial direction, the second annular projection group, the first annular protrusion group is formed on the rear end side than the motor according to any one of claims 1 to 5. And a magnet provided on the front carboxymethyl Yafuto,
And coils,
The motor according to any one of claims 1 to 6, comprising: In the axial direction, the first annular projection group is formed on the tip side of the press-fit surface of the shaft,
In the axial direction, the second annular projection group is the formed on the rear end side of the press-fitting surface of the shaft, motor according to any one of claims 1 to 7. Equipped with a shaft with a press-fit surface,
A first annular projection group and a second annular projection group are formed on the press-fit surface of the shaft,
In the axial direction, the first annular projection group is spaced apart from the second annular projection group,
In the axial direction, the distance between the adjacent annular projections in the first annular projection group and the distance between the adjacent annular projections in the second annular projection group are the first annular projection group and the second annular projection. Motor structure smaller than the group distance .

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