JPH09132040A - Wheel motor with reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain vibration generated by an output shaft from being transmitted to a wheel in the wheel motor with a reduction gear, which is so constituted that its wheel portion and its electric motor portion with a reduction gear are formed into each independent unit respectively. SOLUTION: The wheel motor 1 with a reduction gear is equipped with a housing 60 disposed in the inside of a wheel 3, and with a damper 70 arranged between the housing 60 and the wheel 3, and an electric motor 4 and a gear reducer 5 are built in the inside of the housing 60. The damper 70 is to restrain vibration generated by an output shaft 9 from being propagated outside, it is held between a flange 71 and a hub 72, and the output of the electric motor is transmitted to the wheel 3 through the damper 70.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel motor with a reducer used as a drive source for industrial vehicles such as cargo handling vehicles.

[0002]

2. Description of the Related Art Conventionally, when a wheel motor with a speed reducer is attached to a drive wheel, a special arrangement is made to prevent the vehicle body from interfering with the motor or the speed reducer when the wheel moves up and down or turns. On the other hand, by disposing an electric motor and a planetary gear reducer in the inner space portion of the wheel, and transmitting the rotational output of the electric motor to the wheel via the planetary gear reducer,
A wheel motor configured to rotationally drive this wheel has already been proposed (for example, Japanese Patent Laid-Open No. 2-1).
1419 and JP-A-4-185207).

[0003]

However, in the above-mentioned conventional wheel motor with a speed reducer, a planetary gear speed reducer is adopted as a speed reducer, and an output for transmitting the rotation output of the electric motor to the wheel via the planetary gear speed reducer. The shaft has a structure in which the output is obtained by dividing the shaft in the axial direction of the wheel motor and then aligning the shaft center, so the structure is complicated and difficult to assemble, and the wheel and motor are integrated together. However, the present applicant has a problem that it is difficult to change only the wheel. On the other hand, the applicant of the present invention, for example, as shown in Japanese Patent Application Laid-Open No. 7-96753, has a speed reducer for the wheel portion. We proposed a wheel motor with a reducer, which allows the motor part to be an independent unit and has versatility for changing the wheel part. There.

Thus, the wheel portion and the electric motor portion with a speed reducer are constituted by independent units, respectively, and further, as disclosed in Japanese Patent Laid-Open No. 7-96752, the output shaft penetrates the inside of the electric motor. In addition, when the rotor is configured to be supported by the output shaft via the bearing, the rotor may not be fixed to the application shaft,
Vibrations due to rotor torque fluctuations, gear backlash, etc., are likely to be applied to the output shaft.When attempting to store such an electric motor in the cylindrical space with a bottom formed inside the wheel, the output shaft It was found that the vibration may be transmitted to the rim portion of the wheel and amplified like a drum.

The present invention has been made in view of the above problems, and in a wheel motor with a speed reducer in which a wheel portion and an electric motor portion with a speed reducer are each formed as an independent unit, vibration generated at the output shaft is applied to the wheel. It is an object of the present invention to provide a wheel motor with a reducer capable of suppressing the transmission and thereby reducing the generation of resonance noise amplified in the rim portion of the wheel.

[0006]

In order to achieve the above object, the present invention is to install an electric motor with a gear reducer in a bottomed cylindrical space portion formed inside a wheel and reduce the rotational output by this reducer. Thus, in the wheel motor with a reduction gear that rotationally drives the wheel, the output shaft of the electric motor is fixed to the rim of the wheel via a cushioning member.

Further, preferably, the electric motor includes a stator fixed to a case side, a rotor rotatably provided inside the stator, and a rotational output of the rotor via a gear reducer. It has an output shaft to output, and this output shaft
The rotor is rotatably supported by both side portions of the case while penetrating a rotation center hole of the rotor, and the rotor is rotatably supported by the rotation shaft via a bearing. And

Further, preferably, a cylindrical joint member that rotates integrally with the output shaft is fixed to the output shaft, and a hub into which the joint member is rotatably fitted is fixed to the rim. The joint member and the hub are joined and connected in the rotational direction via the cushioning member.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the structure of a wheel motor with a reducer according to an embodiment of the present invention.

As shown in FIG. 1, a wheel motor 1 with a speed reducer has a housing 60 and a housing 60 arranged inside a wheel 3 having tires (wheels) 2 mounted thereon.
And a damper 70 arranged between 0 and the wheel 3,
The housing 60 contains the electric motor 4 and the gear reducer 5 that decelerates and outputs the rotational output of the electric motor 4. The rotation output of the electric motor 4 is transmitted to the wheel 3 via the gear reducer 5 and the damper 70, and the wheel 3 is rotationally driven by the transmitted rotational force, and the wheel 3 is also rotated.
Resonant sound generated in the is reduced.

The housing 60 is a substantially bowl-shaped outer case 6
A partition case 63 is interposed between the first case (second case) and the inner case 62 (first case). The inner case 62, the partition case 63, and the outer case 61 are integrally fastened and fixed by unillustrated bolts. Also,
Outer case 61, inner case 62 and partition case 63
Is cast by aluminum die casting.

A shaft insertion hole 61a is formed in the center of the outer case 61.
And a partition wall 61b for forming a space S having a horseshoe-shaped cross section perpendicular to the axial direction, which is isolated from the gear reducer 5 inside the outer case 61 (inside the housing 60). Are formed.

On the other hand, on the side of the inner case 62, there are three holes 62 extending from the partition case 63 side toward the outer end surface.
a is formed.

Further, a stator mounting portion 63a bulging toward the inner case 62 is formed on a side portion of the partition case 63, and the stator mounting portion 63a has a hole 62a in the thickness direction of the partition case 63. Three holes 63b extending so as to be continuous are formed. A through hole 63c for inserting (penetrating) the axially long portion of the rotor body 8b in a non-contact state is formed in the center of the partition case 63.

The electric motor 4 is housed in the inner case 62 and is composed of a closed slot iron core.
7, a rotor (rotor) 8 that is rotatably provided inside the stator 7, and an output shaft 9 that outputs the rotational output of the rotor 8 via the gear reducer 5.

The stator 7 has a magnetic pole part core and a yoke part core arranged so as to surround the magnetic pole part core. The magnetic pole portion iron core is formed by laminating a large number of magnetic thin plates (electromagnetic steel plates) on which a plurality of magnetic pole tooth forming projections radially extending outward from a ring-shaped connecting portion through which the rotor 8 is inserted are formed. It is composed by. The magnetic pole teeth are arranged at equal intervals in the circumferential direction of the connecting portion, and a closed slot is formed between the magnetic pole teeth by the connecting portion.

A three-phase field coil 7d is wound around each magnetic pole tooth via a coil bobbin 7c.
Form a stator winding.

The yoke core is formed by laminating a large number of ring-shaped magnetic thin plates each having a plurality of cutouts formed in the inner peripheral portion thereof. Each notch in the inner peripheral portion forms a fitting groove, and the tips of the magnetic pole teeth of the corresponding magnetic pole portion iron core are fitted in each fitting groove.

The outer peripheral portion of the yoke core is provided with a partition case 63.
Is sandwiched between the stator mounting portion 63a and the pressing plate 30,
It is fixed to the stator mounting portion 63a by the bolt 13.

The rotor 8 is provided with a shaft insertion hole 8a, which is a rotation center hole, over the entire axial length of the rotor body 8.
b. A plurality of magnetizing magnets 8c arranged at equal intervals in the circumferential direction are mounted on the outer peripheral portion of the rotor body 8b, and the rotor position is detected on the side surface of the rotor 8 on the side of the partition case 63. Magnets 8d are provided at equal intervals in the circumferential direction.

The axial length of the inner peripheral portion of the rotor main body 8b is longer than the axial length of the outer peripheral portion, and a helical gear constituting the first gear 5a of the gear reducer 5 is formed at the tip of one end thereof. At the other end, a hook 8e is formed which is engageable with the axial withdrawal direction of the output shaft 9.

Further, the outer peripheral portion of the rotor main body 8b having a short axial length is rotatably opposed to the inner peripheral portion of the stator 7, and ball bearings and the like are press-fitted into both ends of the inner peripheral portion of the rotor main body 8b. Is supported by the output shaft 9 through the bearings 14a and 14b of and is configured to rotate about this.

A key 9a and a screw hole 9b for attaching an output transmitted member are formed at one end of the output shaft 9. The intermediate portion of the output shaft 9 is provided with a bearing 18 such as a ball bearing in the shaft insertion hole 61a of the outer case 61, and the other end portion of the output shaft 9 is provided with a bearing 19 such as a ball bearing in a central recess of the inner case 62. Each of them is rotatably supported via. The middle part of the output shaft 9 and the outer case 61
The gap between the shaft insertion hole 61 a and the shaft insertion hole 61 a is sealed by the seal member 27. The output shaft 9 is the shaft insertion hole 8 of the rotor 8.
It rotates while being supported by the bearings 14a and 14b in a.

The electric motor 4 whose main constituent elements are the stator 7 and the rotor 8 is a flat brushless electric motor having a short axial length, and the wheel motor 1 with a reduction gear has the output shaft 9 as a whole. It is configured so that its axial dimension is short.

The gear reducer 5 is a two-stage reducer having a plurality of (four in the present embodiment) gears 5a, 5b, 5c, 5d. That is, the first gear 5a is integrally formed coaxially with the other end side (the left end side in FIG. 1) of the rotor 8 as described above. Second and third gears 5b, 5c
Are fixed to the same rotary shaft (support shaft) 20 so as to rotate integrally with each other, and the second gear 5b is meshed with the first gear 5a.

The rotary shaft 20 is arranged eccentrically with the output shaft 9 and below the output shaft 9. One end of the rotary shaft 20 rotates in a recess of the partition case 63 via a bearing 21 such as a ball bearing, and the other end of the rotary shaft 20 rotates in a recess of the outer case 61 via a bearing 22 such as a ball bearing. It is supported freely.

The fourth (final stage) gear 5d is fixed to the output shaft 9 so as to rotate integrally with the output shaft 9. The third gear 5c is meshed with the fourth gear 5d.
Therefore, when the rotor 8 rotates due to the action of the rotating magnetic field of the stator 7, the first gear 5a integrally formed with the rotor 8 rotates at the same rotation speed as the rotor 8. The rotation output of the first gear 5a is transmitted to the fourth gear 5d after being decelerated by the second and third gears 5b and 5c, and the output shaft 9 is the same as the fourth gear 5d with the decelerated rotation of the fourth gear 5d. Rotor 8 at
And rotate in the same direction.

For example, when the rotor 8 rotates forward at 750 rpm, the output shaft 9 is decelerated by the gear reducer 5 to 1
It rotates forward at 50 rpm and its reduction ratio is 1/5.

A space S having a horseshoe-shaped cross section perpendicular to the axial direction, which is isolated from the gear reducer 5 formed by the partition case 63 and the horseshoe-shaped partition wall portion 61b of the outer case 61, has the horseshoe shape. A control circuit forming first substrate 23 for driving the electric motor 4 formed together is arranged and attached to the partition case 63 with screws (not shown).
On the horseshoe-shaped first substrate 23, various circuit elements (for example, a semiconductor for control) forming a control circuit for driving the electric motor 4 are attached. Thus, by forming the control circuit installation space in the housing 60, it is not necessary to provide a control circuit installation space outside the housing, and by making this space horseshoe-shaped,
In the limited space inside the housing 60, it is possible to take a large space for accommodating the control circuit.

The space between the partition case 63 and the electric motor 4 is driven by a signal from a control circuit formed on the first substrate 23 and supplies a drive current to the electric motor 4. The second substrate 25 for forming a drive circuit. Are arranged. The second substrate 25 is formed of a donut-shaped bus plate whose outer dimensions are smaller than the inner diameter of the stator mounting portion 63a of the inner case 62, and the bus plate is attached to the partition case 63 with screws 25b. The fixed position of the second substrate 25 by the screw 25b is set so as to be included in the projection range of the rotor 8 in the direction of the output shaft 9. The first board 23 and the second board 25 are wired and connected by a cable connector (not shown).

On each surface of the second substrate 25, a plurality of wiring paths (not shown) and through holes connected to the wiring paths are formed. The through holes are arranged at equal intervals along the circumferential direction of the outer peripheral portion of the second substrate 25, and the corresponding end portions 7e of the field coil 7d are penetrated and connected to the through holes. The field coils 7d are connected to each other by connecting and fixing each through hole and the corresponding end 7e of the field coil 7d.

On the surface of the second substrate 25 facing the partition case 63, a plurality of power transistors (power MOSF) for supplying a current to the field coil 7d through its end 7e.
ET) 25a and other circuit elements are attached, and each power transistor 25a and the circuit element are connected to the corresponding printed wiring path by soldering. Each power transistor 25a is connected to the center of the second substrate 25 (output shaft 9
Of the power transistors 25a and the heat radiation surface (the surface facing the partition case 63) of each power transistor 25a is closely contacted with the facing surface of the partition case 63 on the inner case 62 side through an insulating material such as a silicon sheet. In addition, at least a part of the close contact portion with the partition case 63 is included in the projection range of the rotor 8 in the direction of the output shaft 9, and is attached to the second substrate 25. Further, each power transistor 25a is fixed in a state where its heat radiation surface portion is sandwiched between the second substrate 25 and the partition case 63.

A control line 32 for supplying a control signal from the outside is connected to the first substrate 23, and the control line 32 is one of the holes 63b of the stator mounting portion 63a of the partition case 63 and the inner case connected to it. It is guided to the outside of the housing 60 through a hole 62 a of 62. Hole 62 of control line 32
A retaining member 33 is attached to the portion located at a, and when the pull-out force acts from the outside, this force is
It is configured so as not to reach the substrate 23 side.

Similarly, on the second substrate 25, a pair of power lines 31 for supplying a DC drive current of the electric motor 4 from the outside.
Are connected, and each power line 31 has a corresponding stator mounting portion 63.
hole 63b of a and hole 6 of the inner case 62 continuing to it
It is guided to the outside of the housing 60 via 2a. A control line 32 is provided at a portion of each power line 31 located in the hole 63b.
Similarly, a retaining member (not shown) is attached,
When a pulling force is applied from the outside, this force does not reach the second substrate 25 side.

Further, a total of six magnetic detection elements, three for forward rotation and three for reverse rotation, are attached to the second substrate 25 to detect the position of the rotor 8 of the electric motor 4. In this embodiment, the Hall element 26 is used as the magnetic detection element.

The hall elements 26 are arranged at predetermined angular intervals on the second substrate 25 so as to face the magnets 8d mounted on the side surfaces of the rotor 8 in the radial direction.
The rotational position of the rotor 8 is detected based on the detection signal from each Hall element 26. The hall element 26 has three pins, and the three pins are inserted into the holes of the second substrate 25 and soldered.

The damper 70 is for suppressing the vibration generated on the output shaft 9 from spreading to the outside (that is, the wheel 3), and the key 9a so as to rotate integrally with the output shaft 9.
And a flange 71 connected via
A hub 72 that rotatably inserts the element 7 and a highly elastic element 7 that is narrowly attached between the flange 71 and the hub 72.
3 and 3. The flange 71 is formed in a substantially cylindrical shape having an outer peripheral portion 71a having a short axial length and an outer peripheral portion 71b having a long axial length. Similarly, the hub 72 is also formed in a substantially pot-like shape having an outer peripheral portion 72a having a short axial length and an outer peripheral portion 72b having a long axial length, and the outer peripheral portion 72b having a long axial length has a short axial length of the flange 71. It is formed to have the same length as the diameter of the outer peripheral portion 71a. Then, the outer peripheral portion 72 having a short axial length
a, bolt 80 and nut 8 on the rim of wheel 3
A plurality of parts for fixing via 1 (4 in this embodiment)
Individual holes 72c are provided.

FIG. 2 is an enlarged perspective view for explaining the detailed structure of the damper 70, and as described above, the hub 7 is used.
A plurality of holes 72c are provided in the outer peripheral portion 72a having a short axial length. A plurality of elements (two in the present embodiment) for narrowly attaching the element 73 to the outer peripheral portion 72b having a long axial length.
The aluminum insert 72d is fixed by a bolt (not shown). Similarly, a plurality of (two in the present embodiment) aluminum inserts 71d are fixed to the outer peripheral portion 71a having a short axial length of the flange 71 by bolts 71e.

The element 73 has a plurality of (four in the present embodiment) protrusions 73a and an annular portion 73b,
The protruding portion 73a has aluminum inserts 71d and 72d.
The annular portion 73b is narrowed by the outer peripheral portion 71a of the flange 71 having a short axial length and the outer peripheral portion 72b of the hub 72 having a long axial length. That is, the hub 72 is rotatably fitted into the long outer peripheral portion 71b of the flange 71, is supported by the flange 71 in a direction perpendicular to the axial direction, and through the aluminum inserts 71d and 72d and the element 73, It is joined and connected to the flange 71 in the rotational direction.

Then, as shown in FIG. 1, the hub 72 is
It is fastened to the rim of the wheel 3 by the bolt 80 and the nut 81, and the flange 71 is connected to the output shaft 9 by the key 9a.

In this way, the rotation output of the output shaft 9 is
It is transmitted to the flange 71, transmitted to the hub 72 via the element 73, and transmitted to the wheel 3. At this time,
The vibration generated on the output shaft 9 is transmitted to the flange 71, but is dampened by being dampened by the element 73, and the weakened vibration is transmitted to the hub 72. Therefore, a bottomed cylindrical space formed inside the wheel is formed. It is possible to suppress the generation of a resonance sound that is amplified like a drum at the rim portion of the wheel.

Axial load is applied to the hub 72. Since the axial load is supported by the entire inner peripheral portion 72e (that is, the outer peripheral portion 71b having a long axial length of the flange 71),
The load can be distributed appropriately.

Further, since the damper 70 is fixed to the output shaft 9 and the rim of the wheel 3, it is not necessary to form the rim portion of the wheel 3 to have a particularly thick wall, which results in weight and manufacturing cost. Can be reduced, the weight of the vehicle as a whole can be suppressed, and fuel consumption can be reduced.

Further, since the structure of the damper 70 is configured so that the wheel portion and the electric motor portion are independent units, the wheel 3 and the electric motor 4 can be provided with versatility. .

In this embodiment, the four protrusions 7
Although the element 73 having 3a has been described as an example,
It is needless to say that the number of projections is not limited to this, and the number may be increased or decreased according to the power of the electric motor 4 or the like.

[0047]

As described above, according to the present invention,
Since the output shaft of the electric motor is configured to be fixed to the rim of the wheel via the cushioning member, the vibration generated on the output shaft is suppressed from being transmitted to the wheel, and the bottomed cylinder formed inside the wheel is thereby suppressed. The effect that it is possible to suppress the generation of the resonance sound amplified at the rim portion of the wheel in the space is formed. Further, since the output shaft is configured to be fixed to the rim of the wheel through the cushioning member, it is not necessary to form the rim portion of the wheel to be particularly thick, thereby reducing the weight and the manufacturing cost. In addition, the weight of the vehicle as a whole can be suppressed, and the fuel consumption can be reduced.

A cylindrical joint member that rotates integrally with the output shaft is fixed to the output shaft, and a hub into which the joint member is rotatably fitted is fixed to the rim. Since the member and the hub are joined and connected in the rotational direction via the cushioning member, the axial load applied to the hub is supported by the entire cylindrical joint member, and the load can be appropriately distributed. Further, since the wheel portion and the electric motor portion are each configured as an independent unit, it is possible to give versatility to both the wheel and the electric motor.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing the structure of a wheel motor with a reducer according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view for explaining a detailed configuration of the damper shown in FIG.

[Explanation of symbols]

 1 Wheel Motor with Reducer 3 Wheel 4 Electric Motor 5 Gear Reducer 7 Stator 8 Rotor 8a Shaft Insertion Hole (Rotation Center Hole) 9 Output Shafts 14a, 14b Bearing 61 Outer Case (Case) 62 Inner Case (Case) 71 Flange (Joint member) 72 hub 73 element (buffer member)

Claims (3)

[Claims] 1. A wheel motor with a speed reducer, wherein an electric motor having a gear speed reducer is attached to a bottomed tubular space formed inside a wheel, and the wheel is rotationally driven by a rotational output reduced by the speed reducer, A wheel motor with a speed reducer, wherein an output shaft of the electric motor is fixed to a rim of the wheel via a cushioning member. 2. The electric motor includes a stator fixed to a case side, a rotor rotatably provided inside the stator, and an output for outputting a rotational output of the rotor via a gear reducer. An output shaft, the output shaft being rotatably supported by both side portions of the case in a state of penetrating a rotation center hole of the rotor, and the rotor being rotatable by the rotation shaft via a bearing. The wheel motor with a speed reducer according to claim 1, wherein the wheel motor has a speed reducer. 3. A cylindrical joint member that rotates integrally with the output shaft is fixed to the output shaft, and a hub into which the joint member is rotatably fitted is fixed to the rim, and the joint member is fixed. The wheel motor with a speed reducer according to claim 1, wherein the hub and the hub are joined and connected in the rotational direction via the cushioning member.