JP2004129389A - In-wheel motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-wheel motor, capable of always obtaining positive braking force by restraining dimensions in the cross direction from increasing, by the installation of a brake device and eliminating an influence of oil on the brake device. <P>SOLUTION: A brake storage section 8 is opened to the left side face of a rotor hub 6, a drum brake 20 is stored in it, and the brake storage section 8 is closed by a rotor cover 9 to maintain oil-tightness by an O-ring 18. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an in-wheel motor that is arranged in a wheel of a vehicle and rotationally drives a driving wheel, and particularly to a brake structure.
[0002]
[Related background art]
The in-wheel motor, which is arranged in the wheel of the vehicle and drives the drive wheels directly, has various advantages such as space saving on the vehicle body side, elimination of transmissions and differential gears, and elimination of the drive shaft when independent suspension is used. Therefore, it is widely implemented mainly for relatively small vehicles such as forklifts and golf carts.
[0003]
Even in a vehicle equipped with this kind of in-wheel motor, a brake device may be provided similarly to a general vehicle, and in this case, the brake device is integrated with the in-wheel motor (for example, see Patent Reference 1). That is, in the in-wheel motor, a wheel hub is connected to the tip of the rotor shaft to fix the drive wheels, and a hydraulic drum brake is provided at the wheel hub.
[0004]
However, in the above-described brake structure, the dimension of the in-wheel motor in the vehicle width direction (left-right direction) increases by a considerable amount corresponding to the drum brake, so that the suspension arm length is limited and the suspension mechanism is restricted. There was a problem that the vehicle interior space was reduced.
Therefore, an in-wheel motor in which a drum brake is arranged by using a dead space in the motor has been proposed (for example, see Patent Document 2). That is, in the in-wheel motor, a drum brake is provided in a dead space formed on the inner peripheral side of the rotor, and a braking force is obtained by sliding a brake shoe on the inner peripheral surface of the rotor.
[0005]
[Patent Document 1]
Patent No. 2711726 (FIG. 1)
[Patent Document 2]
JP-A-5-278476 (paragraphs 0012 and 0013, FIGS. 1 (a) and 1 (b))
[0006]
[Problems to be solved by the invention]
By the way, in this type of in-wheel motor, oil may be stored in a housing for the purpose of cooling the stator or lubricating a speed reduction mechanism for reducing the rotation of the rotor. However, in the in-wheel motor described in Patent Literature 2, since oil is not assumed to be stored, it is inevitable that oil scattered due to rotation of the rotor or the gears of the reduction mechanism adheres to the drum brake, and friction occurs. There was a problem that the original braking force could not be obtained due to a decrease in the coefficient.
[0007]
Therefore, an object of the present invention is to provide an in-wheel motor that can always obtain a reliable braking force by eliminating the influence of oil on the brake device while suppressing an increase in the size in the vehicle width direction due to the installation of the brake device. To provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 includes disposing an annular stator in a housing in which oil is stored, disposing an annular rotor core on the inner peripheral side of the stator, and connecting the rotor core via a rotor hub. In the in-wheel motor in which the rotor shaft is rotatably supported by the rotor shaft and the rotor shaft is connected to the driving wheel of the vehicle, a brake housing portion formed on one side of the rotor hub and a brake housing portion housed in the brake housing portion are provided. A brake device capable of applying a braking force to the shaft, a rotor cover detachably fixed to the rotor hub so as to close the brake accommodating portion, and a seal member for maintaining oil tightness between the rotor hub and the rotor cover. It is provided with.
[0009]
Therefore, the brake accommodating portion is formed in one side surface of the rotor hub and is located in the dead space on the inner peripheral side of the rotor, and the brake device is accommodated in the rotor accommodating portion. The increase is suppressed.
In addition, the brake housing is closed by the rotor cover, and oil tightness is maintained by the seal member, so that the oil in the housing is prevented from entering the brake housing, and the braking force of the brake device is reduced due to the adhesion of the oil. Is prevented from occurring.
[0010]
According to a second aspect of the present invention, an annular stator is disposed in a housing in which oil is stored, an annular rotor core is disposed on an inner peripheral side of the stator, and the rotor core is rotatable by a rotor shaft via a rotor hub. In an in-wheel motor in which a rotor shaft is supported and connected to a driving wheel of a vehicle, a recess formed in one side of the rotor hub and a brake housing recessed in the housing according to the shape of the recess of the rotor hub. And a brake device housed in the brake housing portion and capable of applying a braking force to the rotor shaft.
[0011]
Therefore, since the brake accommodating portion is formed by recessing the housing in accordance with the concave shape of the rotor hub, the brake accommodating portion is located in a dead space on the inner peripheral side of the rotor, and the brake device is provided in the brake accommodating portion. Since it is accommodated, an increase in the dimension of the in-wheel motor in the vehicle width direction is suppressed.
In addition, since the brake accommodating portion is formed outside the housing, there is naturally no possibility that the oil in the housing adheres to the brake device in the brake accommodating portion. It is prevented beforehand.
[0012]
In addition, since the brake housing is open to the atmosphere, the heat generated by the brake device during braking is directly radiated to the atmosphere without being radiated to the oil in the housing. As a result, it is possible to avoid deterioration of the oil due to heat of the brake device and insufficient cooling of the stator due to an increase in the oil temperature.
According to a third aspect of the present invention, in the second aspect, the recess is formed in the side surface of the rotor hub on the vehicle body side, and the brake device is housed in the brake housing portion recessed on the vehicle body side of the housing according to the shape of the recess. It was done.
[0013]
Therefore, since the brake housing is recessed on the vehicle body side of the housing and the brake device is housed, the reduction mechanism can be freely installed on the output side of the rotor shaft, that is, on the tire side for the purpose of increasing torque, and the in-wheel motor The degree of freedom in design is expanded.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
Hereinafter, a first embodiment in which the present invention is embodied in an in-wheel motor having a drum brake will be described.
The in-wheel motor of this embodiment is provided on each of the left and right rear wheels of the electric vehicle, and is driven and controlled by a controller in accordance with a driver's accelerator operation to individually rotate and drive each rear wheel.
[0015]
FIG. 1 is a cross-sectional view of the in-wheel motor provided on the left rear wheel of the first embodiment as viewed from the rear. In FIG. 1, the right side corresponds to the vehicle body side, and the left side corresponds to the tire side. The housing of the in-wheel motor 1 is composed of a vehicle body-side housing 2a and a tire-side housing 2b. The two housings 2a and 2b are joined from the left and right and fixed by bolts (not shown). Although not shown, the lower end of the strut and the outer end of the lower arm from the vehicle body side are connected to the right side surface of the vehicle body side housing 2a, and the entire in-wheel motor 1 is supported on the vehicle body via these struts and the lower arm. ing.
[0016]
A bearing projection 3 projects leftward from the vehicle body side housing 2a, and a bearing hole 4 penetrates coaxially with the bearing projection 3 from the tire side housing. In the housings 2a and 2b, a rotor hub 6 is supported on the bearing projection 3 via a bearing 5, and a large number of rotor cores 7 made of permanent magnets are fixed to the outer periphery of the rotor hub 6. The rotor hub 6 has a cylindrical shape with a bottom opening to the left and has a brake housing 8 inside. A disk-shaped rotor cover 9 is not shown in the opening of the rotor hub 6 so as to close the brake housing 8. It is detachably fixed by bolts.
[0017]
An annular stator 10 is fixed to the inner periphery of the housings 2a and 2b so as to be located on the outer periphery of the rotor core 7. Although detailed description is omitted, the stator 10 is formed by laminating a large number of electromagnetic steel plates to form an annular stator core, and arranging a number of bobbins around which a stator coil is wound on the stator core. . Although not shown, the stator coils are electrically integrated for each of the U, V, and W phases and then connected to a controller on the vehicle body side.
[0018]
A press-fit hole 9a is formed through the center of the rotor cover 9, and the base end of the rotor shaft 11 is press-fitted and fixed in the press-fit hole 9a. The intermediate portion of the rotor shaft 11 is inserted into the bearing hole 4 of the tire side housing 2b and supported via the bearing 12, while the oil tightness in the housings 2a and 2b is maintained by the oil seal 13 attached to the bearing 12. Have been.
[0019]
The rotor 14 includes the rotor hub 6, the rotor core 7, the rotor cover 9, and the rotor shaft 11, and the entire rotor 14 is rotatably supported by the bearings 5 and 12 in the housings 2 a and 2 b around the rotor shaft 11. I have. The tip of the rotor shaft 11 projects leftward from inside the housings 2a and 2b, and a wheel hub 16 is fixed by a nut 15, and a wheel 17 of a driving wheel is fixed to the wheel hub 16 by a nut (not shown).
[0020]
On the other hand, the oil is stored in the housings 2a and 2b to a height of about 1/3, and the oil is scattered by the rotation of the rotor 14 to exert a cooling effect on the stator 10. An O-ring 18 (seal member) is buried all around the opening of the rotor hub 6, and the periphery of the rotor cover 9 abuts on the O-ring 18, and the space between the rotor hub 6 and the rotor cover 9 is formed. Oil tightness is maintained. An oil seal 19 is provided alongside the bearing 5 of the bearing projection 3 to maintain oil tightness of the bearing portion. As a result, the inside of the brake accommodating portion 8 is kept oil-tight with respect to the outside, that is, the inside of the housings 2a and 2b, and the ingress of the oil stored in the housings 2a and 2b into the brake accommodating portion 8 is prevented. ing.
[0021]
A hydraulic drum brake 20 (brake device) is accommodated in the brake accommodating portion 8 of the rotor hub 6, and the back plate 21 of the drum brake 20 has a tip end of the bearing projection 3 protruding into the brake accommodating portion 8. Fixed to. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1 showing the configuration of the drum brake 20, and a pair of brake shoes 22 of the drum brake 20 are pivotally mounted on the back plate 21 (left side surface). The shoes 22 correspond to the inner peripheral surface of the rotor hub 6.
[0022]
A wheel cylinder 23 is disposed between the upper ends of both brake shoes 22. The wheel cylinder 23 includes a first oil passage 24 formed in the back plate 21, a second oil passage 25 formed in the bearing protrusion 3, And a vehicle-side master cylinder via a brake hose (not shown). Therefore, when the driver performs the brake operation, the hydraulic oil from the master cylinder is supplied to the wheel cylinder 23 through the brake hose, the second oil passage 25, and the first oil passage 24, and the oil pressure causes the wheel cylinder 23 to move to both sides. The brake shoe 22 is urged in the expanding direction, and is brought into sliding contact with the inner peripheral surface of the rotor hub 6 rotating on the outer peripheral side to generate a braking force.
[0023]
The adjustment and repair of the drum brake 20 are performed with the rotor cover 9 removed. First, the wheel hub 16 is removed from the rotor shaft 11, and then the vehicle body side housing 2a and the tire side housing 2b are separated. After removing 9 and opening the inside of the brake accommodating portion 8, a desired operation is performed.
The in-wheel motor 1 of the present embodiment is configured as described above. When the controller sequentially energizes the stator coils of the stator 10 in accordance with the rotation angle of the rotor 14, the magnetic field generated in the stator core causes the rotor 14 to rotate. A rotational force is applied, and the drive wheels are driven to rotate together with the rotor 14, so that the vehicle travels. The controller adjusts the electric power to be supplied to the stator coil based on the accelerator operation amount of the driver, and thereby realizes traveling according to the accelerator operation. Further, when the vehicle is decelerated, the rotor 14 is rotationally driven from the drive wheels along the reverse transmission path, and regenerative electric power generated in the stator coil is charged in a battery (not shown).
[0024]
In the in-wheel motor 1 of the present embodiment, the drum brake 20 is accommodated in the brake accommodating portion 8 formed by using the dead space on the inner peripheral side of the rotor 14, so that the vehicle of the in-wheel motor 1 It is possible to suppress an increase in the dimension in the width direction, thereby preventing a situation in which the suspension mechanism is restricted or the interior space of the vehicle is reduced by the in-wheel motor 1, thereby increasing the degree of freedom in designing the vehicle body.
[0025]
Further, after the brake housing portion 8 housing the drum brake 20 is closed by the rotor cover 9, the oil tightness of the brake housing portion 8 is maintained by the O-ring 18 and the oil seal 19. The oil scattered due to the rotation of the rotor 14 adheres not only to the stator 10 but also to the whole of the housings 2a and 2b including the rotor hub 6; Intrusion is prevented. Therefore, it is possible to prevent a situation in which the friction coefficient between the brake shoe 22 and the inner peripheral surface of the rotor hub 6 is reduced due to the adhesion of oil, and to always obtain a reliable braking force.
[0026]
Although the in-wheel motor 1 of the first embodiment includes the drum brake 20, the type of the brake device is not limited to this, and may be changed to, for example, a disk brake (brake device). Hereinafter, another example of such a configuration will be briefly described. FIG. 3 is a cross-sectional view illustrating an in-wheel motor having a disk brake according to another example of the first embodiment, and FIG. 4 is a diagram illustrating the configuration of the disk brake. FIG. 4 is a cross-sectional view taken along line IV-IV. A bracket 31 is fixed to the bearing protrusion 3 instead of the back plate 21, and a caliper 33 of a disc brake 32 is supported at the tip of the bracket 31. A base end side of the rotor shaft 11 projects into the brake accommodating portion 8 to fix a brake rotor 34 of the disc brake 32, and one side of the brake rotor 34 is located between pads (not shown) of the caliper 33.
[0027]
The supply of the hydraulic oil to the caliper 33 is the same as in the first embodiment, and includes a first oil passage 35 formed in the bracket 31, a second oil passage 36 formed in the bearing projection 3, and a brake hose (not shown). Hydraulic oil is supplied from the master cylinder on the vehicle body side via the, and the hydraulic pressure causes the caliper 33 to pinch the brake rotor 34 with the pad to generate a braking force.
[0028]
Although the overlapping description is omitted, also in this alternative example, the disc brake 32 is arranged on the inner peripheral side of the rotor 14 so that the increase in the size of the in-wheel motor 1 in the vehicle width direction can be suppressed, and the oil tightness can be reduced. By accommodating the disc brake 32 in the held brake accommodating portion 8, the effect of oil on the disc brake 32 can be eliminated and a reliable braking force can always be obtained.
[0029]
[Second embodiment]
Hereinafter, a second embodiment in which the present invention is embodied in another in-wheel motor having a drum brake will be described. The difference between the present embodiment and the first embodiment lies in the shapes of the rotor hub 41 and the vehicle body-side housing 2a and the arrangement of the drum brake 43. Therefore, common parts are denoted by the same reference numerals and description thereof is omitted. Then, the differences will be mainly described.
[0030]
FIG. 5 is a sectional view showing an in-wheel motor having a drum brake according to the second embodiment. The rotor hub 41 has a cylindrical shape with a bottom opening rightward, and the right side surface of the vehicle body side housing 2a is recessed about the rotor shaft 11 according to the shape of the recess 41a formed thereby. In the present embodiment, the recessed portion is a brake accommodating portion 42, and a drum brake 43 (brake device) is accommodated in the brake accommodating portion 42.
[0031]
The rotor shaft 11 is inserted into a bearing hole 44 formed in the vehicle body side housing 2a and supported via a bearing 45, while oil tightness in the housings 2a and 2b is maintained by an oil seal 46 provided alongside the bearing 45. ing. A base end of the rotor shaft 11 projects from the bearing hole 44 into the brake accommodating portion 42, and a brake drum 47 is fixed. The brake drum 47 has a bottomed cylindrical shape that opens leftward.
[0032]
A wheel cylinder 48 is provided in the brake accommodating portion 42 of the vehicle body side housing 2a so as to be located in the brake drum 47. The wheel cylinder 48 is provided with an oil passage 49 formed in the vehicle body side housing 2a and a brake (not shown). Hydraulic oil is supplied from a master cylinder on the vehicle body side via a hose, and the hydraulic pressure urges a brake shoe (not shown) in the expanding direction so as to make sliding contact with the inner peripheral surface of a brake drum 47 rotating on the outer peripheral side. Generates braking force. The structure of the drum brake 43 such as a brake shoe is the same as that of the first embodiment described with reference to FIG.
[0033]
The drum brake 43 is accommodated in the brake accommodating portion 42 formed by recessing the vehicle body side housing 2a according to the concave shape of the rotor hub 6, and as a result, the drum brake 43 is Will be arranged by using the dead space. Therefore, similarly to the first embodiment, the increase in the dimension of the in-wheel motor 1 in the vehicle width direction is suppressed, and the restriction of the suspension mechanism and the decrease of the interior space of the vehicle are prevented. Can be expanded.
[0034]
Further, unlike the first embodiment in which the brake accommodating portions 8 are provided in the housings 2a and 2b, in the present embodiment, the brake accommodating portions 42 are formed outside the housings 2a and 2b. There is no possibility that the oil in the inside will adhere to the drum brake 43 in the brake accommodating portion 42, and it is possible to prevent a situation in which the friction coefficient between the brake shoe and the inner peripheral surface of the brake drum 47 decreases due to the adhesion of the oil. As a result, a reliable braking force can always be obtained.
[0035]
In addition, since the brake housing 42 is open to the atmosphere, the heat generated by the drum brake 43 during braking is dissipated directly into the atmosphere. That is, in the first embodiment in which the brake accommodating portions 8 are provided in the housings 2a and 2b, the heat of the drum brake 20 is radiated to the oil in the housings 2a and 2b. Deterioration may be accelerated or cooling of the stator 10 may become insufficient due to an increase in oil temperature. On the other hand, in the present embodiment, since the heat release of the drum brake 43 is performed by the atmosphere without relying on the oil, there is no possibility that these problems occur, and the reliability of the in-wheel motor 1 can be improved. There is also.
[0036]
By the way, in the present embodiment, the brake housing 42 is provided on the vehicle body side of the housings 2a and 2b to house the drum brake 43, but the brake housing 43 may be provided on the tire side of the housings 2a and 2b. However, when a speed reduction mechanism is added to the in-wheel motor 1 for the purpose of increasing the torque, the speed reduction mechanism is necessarily disposed on the output side of the rotor shaft 11, that is, on the tire side of the housings 2a and 2b. Is restricted to the vehicle body side. In addition, when the brake accommodating portion 42 is provided on the tire side of the housings 2a and 2b, the brake oil passage from the master cylinder on the vehicle body side to the drum brake 43 becomes long, and the configuration becomes complicated. Therefore, when the brake accommodating portion 43 is arranged on the vehicle body side of the housings 2a and 2b as in the present embodiment, the degree of freedom in designing the in-wheel motor 1 with respect to the speed reduction mechanism and the brake oil passage can be increased. The advantage is also obtained.
[0037]
The in-wheel motor 1 of the second embodiment has the drum brake 43, but may be changed to, for example, a disk brake (brake device) as described in the first embodiment. FIG. 6 is a cross-sectional view showing an in-wheel motor having a disc brake according to another example of the second embodiment. A bracket 51 is provided upright in the brake accommodating portion 42, and a disc brake is provided at the tip of the bracket 51. 52 calipers 53 are supported. Hydraulic oil is supplied to the caliper 53 from the master cylinder on the vehicle body via a brake hose 54, and the caliper 53 generates a braking force by clamping the brake rotor 55 with the pad by the hydraulic pressure.
[0038]
Although a duplicate description is omitted, also in this alternative example, by arranging the disc brake 52 on the inner peripheral side of the rotor 14, it is possible to suppress an increase in the dimension of the in-wheel motor 1 in the vehicle width direction and to increase the housing 2 a. , 2b, the disc brake 52 is accommodated in the brake accommodating portion 42, so that the effect of oil on the disc brake 52 is eliminated to always obtain a reliable braking force. Since the generated heat is dissipated into the atmosphere, the deterioration of the oil due to the heat of the disc brake 52 and the insufficient cooling of the stator 10 due to an increase in the oil temperature can be avoided, and the reliability of the in-wheel motor 1 can be improved. .
[0039]
The embodiment has been described above, but aspects of the present invention are not limited to this embodiment. For example, in each of the above embodiments, the in-wheel motor 1 provided on the rear wheel of the electric vehicle is embodied. However, the present invention is not limited to this. For example, instead of the rear wheel, the in-wheel motor 1 may be mounted on the front wheel or all wheels. The wheel motor 1 may be provided, or the present invention may be embodied as an in-wheel motor 1 for a hybrid vehicle including an engine as well as a motor as a driving source for driving.
[0040]
【The invention's effect】
As described above, according to the in-wheel motor of the first aspect of the present invention, since the brake housing is formed in one side of the rotor hub and the brake device is housed inside, the dead space on the inner peripheral side of the rotor is used. As a result, the brake device is housed in the housing, the increase in the dimension in the vehicle width direction due to the installation of the brake device can be suppressed, and the brake housing is closed by the rotor cover to maintain oil tightness by the seal member. A situation in which the braking force of the brake device is reduced due to the adhesion of the oil can be prevented, and a reliable braking force can always be obtained.
[0041]
According to the in-wheel motor according to the second aspect of the present invention, the housing is recessed according to the concave shape of the rotor hub to form a brake accommodating portion, and the brake device is accommodated therein, so that the dead space on the inner peripheral side of the rotor is reduced. The brake device is housed by utilizing the brake device, so that the dimension increase in the vehicle width direction due to the installation of the brake device can be suppressed, and the brake housing portion is formed outside the housing, so that the oil in the housing adheres to the brake and the brake Preventing the situation where the braking force of the device is reduced, a reliable braking force is always obtained, and the heat generated by the brake device during braking is dissipated into the atmosphere. The reliability of the stator can be improved by avoiding insufficient cooling of the stator due to an increase in the oil temperature.
[0042]
According to the in-wheel motor according to the third aspect of the present invention, in addition to the third aspect, the brake device is housed by recessing the brake housing portion on the side of the housing on the vehicle body side, so that the deceleration mechanism can be freely provided on the tire side of the housing. And the degree of freedom in designing the in-wheel motor can be expanded.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an in-wheel motor including a drum brake according to a first embodiment.
FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, showing a configuration of a drum brake.
FIG. 3 is a cross-sectional view illustrating an in-wheel motor including a disc brake according to another example of the first embodiment.
FIG. 4 is a sectional view taken along the line IV-IV of FIG. 3, showing a configuration of the disc brake.
FIG. 5 is a sectional view showing an in-wheel motor including a drum brake according to a second embodiment.
FIG. 6 is a cross-sectional view illustrating an in-wheel motor including a disc brake according to another example of the second embodiment.
[Explanation of symbols]
2a Body side housing 2b Tire side housing 6, 41 Rotor hub 7 Rotor core 8, 42 Brake accommodating part 9 Rotor cover 10 Stator 11 Rotor shaft 18 O-ring (seal member)
20,43 Drum brake (braking device)
32,52 Disc brake (brake device)
41a recess

Claims (3)

An annular stator is disposed in a housing in which oil is stored, an annular rotor core is disposed on the inner peripheral side of the stator, and the rotor core is rotatably supported by a rotor shaft via a rotor hub. In an in-wheel motor having a shaft connected to driving wheels of a vehicle,
A brake housing portion formed on one side of the rotor hub,
A brake device housed in the brake housing portion and capable of applying a braking force to the rotor shaft;
A rotor cover detachably fixed to the rotor hub to close the brake housing,
An in-wheel motor comprising: a seal member that keeps oil tight between the rotor hub and the rotor cover. An annular stator is disposed in a housing in which oil is stored, an annular rotor core is disposed on the inner peripheral side of the stator, and the rotor core is rotatably supported by a rotor shaft via a rotor hub. In an in-wheel motor having a shaft connected to driving wheels of a vehicle,
A recess formed on one side of the rotor hub,
A brake housing recessed in the housing according to the shape of the recess of the rotor hub;
An in-wheel motor comprising: a brake device housed in the brake housing portion and capable of applying a braking force to the rotor shaft. The recess is formed in the side surface of the rotor hub on the vehicle body side, and the brake device is housed in a brake housing recessed on the vehicle body side of the housing according to the shape of the recess. 2. The in-wheel motor according to 2.

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