JP7319087B2 - Rotating electric machine and in-wheel motor using this rotating electric machine - Google Patents

Description

The present invention relates to a rotating electrical machine having a variable magnetic flux mechanism and an in-wheel motor using this rotating electrical machine.

2. Description of the Related Art Conventionally, a rotary electric machine is known that can obtain output characteristics according to the rotation speed by adjusting the output of the rotary electric machine at low speed and high speed. Various structures are known for such a rotating electrical machine. A rotary electric machine is known in which an armature coil and a core are provided on a stator, and a magnet is provided so as to face the core.

According to such a rotating electric machine, when rotating at a low speed, the stator is axially moved by the moving means so that the facing area between the stator and the rotor increases, thereby increasing the effective magnetic flux passing through the stator. During high-speed rotation, the stator is moved so as to reduce the facing area between the stator and the rotor so that the effective magnetic flux passing through the stator becomes smaller, realizing high-speed rotation. there is

JP 2008-148516 A

However, according to the conventional rotating electrical machine, the moving means is capable of moving the stator by an actuator such as a driving motor. and the rotating shafts are arranged substantially parallel to each other, so mounting space is required for two axes, making it difficult to reduce the size of the actuator. There is a problem that the bearing or the like that supports the rotation shaft is damaged early due to the

Also, in order to prevent early damage to the bearings that rotatively support such a rotating shaft, it is conceivable to arrange the drive shaft of the actuator and the rotating shaft of the rotating electric machine coaxially, but if such an arrangement is adopted, Also, since the moment of inertia increases as the weight of the parts increases, there is also the problem that it takes a long time to reach the required rotational speed.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-described problems. intended to provide

A rotating electric machine according to the present invention for solving the above problems has a stator having an armature coil, and magnets arranged rotatably with respect to the stator with a predetermined gap therebetween and facing the stator. In a rotary electric machine including a rotor, the stator is attached to a movement mechanism that is movable in a direction of the rotation axis, and the movement mechanism includes a shaft member penetrating the stator and an outer peripheral surface of the shaft member. a ball spline nut member and a ball screw nut member assembled together; and a drive source for applying a rotational force to the ball screw nut member. and a rolling groove in which the rolling element can roll is formed, the rolling groove being a ball spline groove in which the ball spline nut member is assembled so as to be movable along the axial direction; The ball screw nut member has a spiral ball screw groove to which the ball screw nut member is axially movably assembled, and the ball spline groove and the ball screw groove are arranged adjacent to each other. .

According to the rotary electric machine of the present invention, the movement mechanism includes a shaft member passing through the stator, a ball spline nut member and a ball screw nut member assembled to the outer peripheral surface of the shaft member, and a rotational force applied to the ball screw nut member. A plurality of rolling elements for rotatably holding the rotor are assembled to the outer peripheral surface of the shaft member, and rolling grooves are formed in which the rolling elements can roll. In addition, it is possible to reduce the size of the rotary electric machine, reduce the weight of the component parts of the movement mechanism, and shorten the time required to reach the required rotation speed.

1 is an axial sectional view of a rotary electric machine according to an embodiment of the present invention; FIG. 1 is a configuration diagram of a moving mechanism for a rotating electric machine according to an embodiment of the present invention; FIG. 1 is an axial cross-sectional view of a rotary electric machine according to an embodiment of the present invention, showing a state in which a stator is extracted from a mover; FIG.

EMBODIMENT OF THE INVENTION Hereinafter, it demonstrates, referring drawings for embodiment of the rotary electric machine which concerns on this invention. In addition, the following embodiments do not limit the invention according to each claim, and not all combinations of features described in the embodiments are essential for the solution of the invention. .

FIG. 1 is an axial cross-sectional view of a rotating electric machine according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a moving mechanism for the rotating electric machine according to an embodiment of the present invention, and FIG. FIG. 2 is an axial cross-sectional view of the rotating electric machine according to the embodiment, showing a state in which the stator is pulled out from the mover;

As shown in FIG. 1, a rotating electrical machine 10 according to the present embodiment is preferably used as a so-called in-wheel motor incorporated in a wheel 1 of an automobile or the like. A wheel 1 is attached to the vehicle body of an automobile and includes an axle 4 that rotatably supports the wheel 1, a wheel 3, and a tire 2 made of an elastic material such as rubber attached to the outer peripheral surface of the wheel 3. .

The rotating electric machine 10 according to the present embodiment is arranged inside the wheel 3, and by transmitting the rotational force of the rotating electric machine 10 to the wheel 3, it generates the driving force of the automobile to which the rotating electric machine 10 is attached. there is

A rotating electric machine 10 according to the present embodiment includes a stator 11 in which armature coils each having a wire wound around a core (not shown) are arranged in the circumferential direction, and rotates with respect to the stator 11 with a predetermined gap therebetween. A freely arranged rotor 12 is provided. It should be noted that various conventionally well-known winding methods can be adopted for the winding method of the armature coil.

The rotor 12 has a back yoke 13 made of conductive metal or the like, and magnets 14 arranged to face the stator 11. The back yoke 13 is attached to the wheel 3 in a wheel housing 15. , and the wheel 3 rotates as the rotor 12 rotates. The facing surfaces of the stator 11 and the rotor 12 are formed to be inclined so as to have slopes extending in a direction intersecting the rotation axis direction of the axle 4 .

The wheel housing 15 is a hollow disk-shaped member and is assembled so as to sandwich the radially extending flange portion of the back yoke 13 . Further, inside the wheel housing 15, a moving mechanism 20, which will be described later, is accommodated. Further, the wheel housing 15 is rotatably attached to the axle 4 by hub members 16 attached to both ends in the axial direction.

The stator 11 is also attached to a moving mechanism 20 that can move in the axial direction of the axle 4 . The moving mechanism 20 includes a ball spline nut member 24 which is arranged so that the axle 4 is coaxial with the rotation center axis of the stator 11 and is non-rotatably attached to the outer peripheral surface of the axle 4, and a ball spline nut member 24 which is rotatably attached to the outer peripheral surface of the axle 4. A ball screw nut member 25 is provided.

Further, the ball screw nut member 25 is configured such that a rotational force is imparted by a drive motor 27 as a drive source having a gear 28 attached to the output shaft. With this configuration, the rotation of the drive motor 27 causes the gear 28 to rotate, and the gear 28 meshes with the outer peripheral surface of the ball screw nut member 25 to move the drive motor 27 to the ball screw nut member 25 . It transmits rotational force.

As shown in FIG. 2, the axle 4 is a hollow shaft in which a through hole 21 is formed in the axial direction. A spiral ball screw groove 23 is formed on the other end side. Ball spline groove 22 and ball screw groove 23 are formed adjacent to each other near the center of axle 4 . By arranging the ball spline grooves 22 and the ball screw grooves 23 adjacent to each other in this way, the required stroke amount of the moving mechanism 20 is ensured.

A pair of rolling grooves 29, 29 are formed on the outer surface of the axle 4 so that rolling elements, which will be described later, can roll. The rolling groove 29 is formed along the circumferential direction of the axle 4 and is formed on the end side of the axle 4 in the axial direction. That is, the rolling groove 29 is arranged closer to the shaft end than the ball spline groove 22 and the ball screw groove 23 respectively, and the ball spline groove 22 and the ball screw groove 23 are arranged between the pair of rolling grooves 29. It is

The ball spline nut member 24 is a cylindrical member, and the axle 4 is inserted through its inner circumference. Further, a second ball spline groove 24a corresponding to the ball spline groove 22 of the axle 4 is formed on the inner peripheral surface of the ball spline nut member 24, and between the ball spline groove 22 and the second ball spline groove 24a. A ball spline nut member 24 is assembled so as to be movable in the axial direction of the axle 4 by interposing rolling elements (not shown). One end of the ball spline nut member 24 is inserted into the inner ring of the bearing 26 and attached to the moving base 30 of the stator 11 as shown in FIG.

The ball screw nut member 25 is an annular member having a spiral second ball screw groove 25a corresponding to the ball screw groove 23 formed on the inner circumference, and a third screw groove 25b with which the gear 28 meshes on the outer peripheral surface. formed. The ball screw nut member 25 is rotatably assembled to the axle 4 by interposing a rolling element (not shown) between the second ball screw groove 25 a and the ball screw groove 23 .

A diameter-reduced portion 25c to be inserted into the inner ring of the bearing 26 is formed on one end side of the ball screw nut member 25. With the diameter-reduced portion 25c inserted into the bearing 26, the ball screw nut member 25 is is attached to the inner ring of the bearing 26.

Further, as shown in FIG. 1, second rolling grooves 33 corresponding to the rolling grooves 29 formed on the outer surface of the axle 4 are formed on the inner peripheral surface of the insertion hole into which the axle 4 of the hub member 16 is inserted. are formed, and a plurality of rolling elements 32 are arranged between the rolling groove 29 and the second rolling groove 33 .

In the rotary electric machine 10 according to the present embodiment configured as described above, when the drive motor 27 of the moving mechanism 20 is rotated to rotate the ball screw nut member 25 via the gear 28 , the ball screw nut member 25 is rotated by the axle 4 . It moves axially along the ball screw groove 23 formed in the . Since the ball screw nut member 25 is attached to the ball spline nut member 24 via the bearing 26 , the moving base 30 is axially moved together with the stator 11 .

As described above, the rotary electric machine 10 according to the present embodiment rotates the ball screw nut member 25 by the driving motor 27 of the moving mechanism 20 , thereby moving the stator 11 in the axial direction so as to insert and remove the stator 11 with respect to the rotor 12 . , the output characteristics can be varied according to the relative position of the stator 11 with respect to the rotor 12 .

More specifically, when the stator 11 is fully inserted into the rotor 12, the facing area between the stator 11 and the rotor 12 is the largest, and the gap between the stator 11 and the rotor 12 is also the largest. Since it is in a small state, the output characteristics of the rotary electric machine 10 are high torque and low rotation. In such a state, the output characteristics are most suitable when the speed is slow but high torque is required, such as when starting an automobile.

In this state, since the back electromotive force rises, power supply to the armature coil 11a is stopped, and during deceleration for braking the wheels 1, the back electromotive force rises, enabling efficient power generation. It is possible to act as a highly efficient regenerative brake.

On the other hand, when the drive motor 27 is rotated to apply a rotational force to the ball screw nut member 25, as shown in FIG. It moves axially while rotating along the ball screw groove 23 .

When the moving mechanism 20 is further driven, the stator 11 is pulled out from the rotor 12 to the maximum, the facing area between the stator 11 and the rotor 12 is the smallest, and the gap between the stator 11 and the rotor 12 is the smallest. is the largest state. In this state, the counter electromotive force drops, and the output characteristics of the rotating electric machine 10 are low torque and high rotation. When the stator 11 is pulled out from the rotor 12 to the maximum in this manner, the output characteristics are most suitable for high-speed running, which does not require torque.

Since the opposing surfaces of the stator 11 and the rotor 12 are both formed as slopes, the gap between the stator 11 and the rotor 12 is adjusted along the inclination of the slope by extracting the stator 11 in the axial direction. is designed to be large. Furthermore, since the amount of movement of the stator 11 can be adjusted steplessly by the amount of rotation of the ball screw nut member 25 by the drive motor 27, the facing area and the gap between the stator 11 and the rotor 12 are It can be adjusted steplessly according to the amount of movement.

In the rotary electric machine 10 according to the present embodiment configured as described above, the axle 4 is formed with the ball spline groove 22, the ball screw groove 23 and the rolling groove 29, so that the axle 4, the ball spline nut member 24, the ball The diameter of the screw nut member 25 can be reduced, and the size of the rotary electric machine 10 can be reduced. In addition, along with this miniaturization, the drive motor 27 and the like can be housed in the wheel housing 15 at the same time, so that the sealing performance of the moving mechanism 20 is improved and the rotary electric machine 10 can be driven without being affected by the weather. In addition, injury due to direct contact with the moving mechanism 20 in operation can be prevented.

Further, since the rotating electric machine 10 according to the present embodiment is rotatably held with respect to the axle 4 by the hub members 16 disposed at both ends in the axial direction of the wheel housing 15, the rotating electric machine 10 can be 10 weight reduction can be achieved, and along with the weight reduction, it is possible to shorten the time required to reach the required number of rotations and improve the response performance.

Furthermore, since the rotary shaft and the drive shaft are arranged coaxially, it is possible to reduce the size of the rotary electric machine 10 . Furthermore, since the rotary electric machine 10 according to the present embodiment has a deceleration effect due to the ball screw nut member 25 and the ball screw groove 23 formed on the outer surface of the axle 4, the output of the drive motor 27 can be reduced. By reducing the size of the drive motor 27, the rotary electric machine 10 can be further reduced in size.

Furthermore, since the moving mechanism 20 moves the stator 11 by the ball screw nut member 25 and the ball spline nut member 24, it is possible to control the movement of the stator 11 with good responsiveness and high energy efficiency. Become. Further, since the amount of movement by the moving mechanism 20 is controlled by the amount of rotation of the ball screw nut member 25, the position of the stator 11 can be arbitrarily set according to the required output characteristics, thereby obtaining the most suitable output characteristics. It becomes possible to drive the rotary electric machine 10 with.

In the above-described embodiment, the axle 4, the ball spline nut member 24, and the ball screw nut member 25 are assembled via rolling elements. may be assembled so that they slide against each other. Further, in the rotating electric machine 10 according to the present embodiment described above, a case where the rotating electric machine 10 according to the present embodiment is applied to the wheel 1 of an automobile has been described, but the application is not limited to automobiles. It may be applied to generators, press machines, and the like. It is clear from the description of the scope of claims that forms with such modifications or improvements can also be included in the technical scope of the present invention.

4 axle, 10 rotary electric machine, 11 stator, 12 rotor, 20 movement mechanism, 24 ball spline nut member, 25 ball screw nut member, 27 drive source, 29 rolling groove.

Claims (4)

A rotating electrical machine comprising a stator having an armature coil and a rotor rotatably arranged with respect to the stator with a predetermined gap and having a magnet facing the stator,
The stator is attached to a moving mechanism that can move in the direction of the rotation axis,
The moving mechanism includes a shaft member passing through the stator, a ball spline nut member and a ball screw nut member assembled to the outer peripheral surface of the shaft member, and a drive source that imparts rotational force to the ball screw nut member. with
A plurality of rolling elements for rotatably holding the rotor are assembled to the outer peripheral surface of the shaft member, and rolling grooves are formed in which the rolling elements can roll ,
The rolling groove includes a ball spline groove to which the ball spline nut member is axially movably assembled, and a spiral ball screw groove to which the ball screw nut member is axially movably assembled. , wherein the ball spline groove and the ball screw groove are arranged adjacent to each other . In the rotary electric machine according to claim 1 ,
A pair of the rolling grooves are formed along the rotation axis direction,
A rotary electric machine, comprising a hub member having opposing rolling grooves corresponding to the rolling grooves. In the rotary electric machine according to claim 2 ,
A rotary electric machine, wherein the hub member is attached to a case member that houses the stator, the rotor, and the moving mechanism. An in-wheel motor using the rotary electric machine according to any one of claims 1 to 3 .

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