JP2020085013A - In-wheel structure for vehicle - Google Patents

Abstract

To obtain an in-wheel structure for a vehicle of a new configuration with less inconvenience such as enabling further downsizing.SOLUTION: An in-wheel structure for a vehicle comprises a drive unit that has: a drum brake having, for example, a cylindrical drum; a motor which has a rotor, at least a part of which is housed in a cylinder of a cylindrical wheel, and which is located radially so as to be displaced from the center of rotation of the wheel; a speed reduction mechanism that reduces the rotation of the rotor and transmits it to the wheel. A part of at least one of the motor and the speed reduction mechanism is located inside the cylinder of the drum.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a vehicle in-wheel structure.

BACKGROUND ART Conventionally, there is known a vehicle in-wheel structure in which a drum brake, a vehicle driving motor, and a speed reduction mechanism are arranged side by side in an axial direction of a wheel rotation center (for example, Patent Document 1).

Japanese Patent No. 5690153

In the above-described conventional vehicle in-wheel structure, the drum brake, the speed reduction mechanism, and the motor are arranged in the axial direction of the rotation center of the wheel. Therefore, there is a case in which the size is easily increased in the axial direction and it may be difficult to mount the vehicle in the vehicle. ..

Therefore, one of the objects of the present invention is to obtain a vehicle in-wheel structure having a novel configuration with less inconvenience, for example, enabling further downsizing.

The vehicle in-wheel structure of the present disclosure includes, for example, a drum brake having a cylindrical drum, and a rotor having at least a part housed in a cylinder of a cylindrical wheel in a radial direction from a rotation center of the wheel. A drive unit having a motor positioned deviating from the motor and a reduction mechanism that reduces the rotation of the rotor and transmits the rotation to the wheel, wherein at least one of the motor and the reduction mechanism has a part, It is located in the cylinder of the drum.

In the vehicle in-wheel structure described above, the motor is positioned to be displaced from the center of rotation of the wheel in the radial direction, and at least one of the motor and the speed reduction mechanism is positioned to the inner side of the inner peripheral surface of the drum in the radial direction. Therefore, the vehicle in-wheel structure can be downsized in the axial direction.

FIG. 1 is an exemplary and schematic cross-sectional view of a vehicle in-wheel structure of an embodiment. FIG. 2 is an exemplary and schematic perspective view of a part of the vehicle in-wheel structure of the embodiment as viewed from the vehicle width direction outer side. FIG. 3 is an exemplary and schematic perspective view of a part of the vehicle in-wheel structure of the embodiment as viewed from the inside in the vehicle width direction.

Hereinafter, exemplary embodiments of the present invention will be disclosed. The configurations of the embodiments shown below, and the actions and results (effects) provided by the configurations are examples. The present invention can be realized by a configuration other than the configurations disclosed in the following embodiments. Further, according to the present invention, at least one of various effects (including derivative effects) obtained by the disclosed configuration and a similar configuration can be obtained.

Further, in the present specification, the ordinal numbers are given for convenience of distinguishing parts, parts, and the like, and do not indicate the priority order or the order. Further, in each figure, for convenience, the vehicle front is indicated by an arrow X, the vehicle upper side is indicated by an arrow Z, the vehicle width direction outer side is indicated by an arrow Y1, and the vehicle width direction inner side is indicated by an arrow Y2. ing. Further, hereinafter, the axial direction of the rotation center Ax1 is simply referred to as the axial direction, the radial direction of the rotation center Ax1 is simply referred to as the radial direction, and the circumferential direction of the rotation center Ax1 is simply referred to as the circumferential direction.

[overall structure]
FIG. 1 is a cross-sectional view of the wheel 1 and the in-wheel structure 2, and FIG. 2 is a perspective view of the in-wheel structure 2 seen from the vehicle width direction outer side. The drum 31 of the drum brake 30 is not shown in FIG.

As shown in FIG. 1, the in-wheel structure 2 is housed in the cylinder of a bottomed cylindrical wheel 1. The wheel 1 has a side wall 1a and a peripheral wall 1b. The side wall 1a has a disk shape that intersects a direction parallel to the axial direction and is provided with an opening (not shown), and the peripheral wall 1b has a cylindrical shape that extends inward in the vehicle width direction from the peripheral edge of the side wall 1a.

The in-wheel structure 2 has a drum brake 30 and a drive unit 40.

[Drum brake]
The drum brake 30 includes a drum 31, a backing plate 32, a brake shoe 33, and a pressing mechanism 34.

The drum 31 has a side wall 31a and a peripheral wall 31b. The side wall 31a has a disc shape intersecting with a direction parallel to the axial direction, and the peripheral wall 31b has a cylindrical shape extending inward in the vehicle width direction from the peripheral edge of the side wall 31a. The side wall 31a is connected to the side wall 1a of the wheel 1 via a bolt 1c. Therefore, the drum 31 rotates around the rotation center Ax1 together with the wheel 1. The peripheral wall 31b has a cylindrical shape centered on the rotation center Ax1. The inner peripheral surface 31c of the peripheral wall 31b is also referred to as a cylindrical inner surface, and is a braking surface on which the brake shoe 33 is pressed and braked. The drum 31 and the wheel 1 may be joined together by a stud bolt and a nut.

The backing plate 32 has a disk shape that intersects a direction parallel to the axial direction, and covers the space inside the cylinder of the drum 31 from the vehicle width direction inner side. The backing plate 32 has an outer surface 32a on the outer side in the vehicle width direction and an inner surface 32b on the inner side in the vehicle width direction. Further, the backing plate 32 is provided with an opening 32c, and the drive unit 40 penetrates the opening 32c. That is, the drive unit 40 has a portion located inside the cylinder of the drum 31 and a portion outside the cylinder of the drum 31, that is, a portion located inside the drum 31 in the vehicle width direction. Further, as shown in FIG. 2, a protruding portion 32d that protrudes outward in the vehicle width direction is provided on the peripheral portion of the rear portion of the backing plate 32.

Two arcuate brake shoes 33 centering on the rotation center Ax1 are located outside the backing plate 32 in the vehicle width direction. The brake shoe 33 is movably supported by the backing plate 32 along the outer surface 32 a of the backing plate 32. The outer peripheral surface 33a of the lining of the brake shoe 33 is pressed against the inner peripheral surface 31c (FIG. 1) of the drum 31, whereby the drum 31 and thus the wheel 1 are braked. The brake shoe 33 includes a sliding position (braking position, not shown) in which the outer peripheral surface 33a slides with the inner peripheral surface 31c, and a separated position Pn (non-contact position) in which the outer peripheral surface 33a is separated from the inner peripheral surface 31c more than the sliding position. (Braking position). The outer peripheral surface 33a may be referred to as a braking surface or a sliding surface, and the inner peripheral surface 31c may be referred to as a braking surface or a sliding surface. The brake shoe 33 is an example of a braking member.

The two brake shoes 33 are arranged vertically separated from each other. The front end 33b of the brake shoe 33 is connected to the pressing mechanism 34, and the rear end 33c of the brake shoe 33 is supported by the protrusion 32d. The protrusion 32d is an example of an anchor that supports the brake shoe 33 so as to be movable or rotatable. The protruding portion 32d is located between the rear end 33a2 of the outer peripheral surface 33a (lining) of the upper brake shoe 33 and the rear end 33a2 of the outer peripheral surface 33a of the lower brake shoe 33.

A pressing mechanism 34 is provided on the front peripheral edge of the backing plate 32 in a state of protruding outward in the vehicle width direction. The pressing mechanism 34 is located between the front end 33a1 of the outer peripheral surface 33a (lining) of the upper brake shoe 33 and the front end 33a1 of the outer peripheral surface 33a of the lower brake shoe 33. The pressing mechanism 34 is, for example, a hydraulic cylinder that accommodates a piston so that the piston can reciprocate. The pressing mechanism 34 presses the front end portions 33b of the two brake shoes 33 so as to be vertically separated from each other in response to the increase in the hydraulic pressure in the hydraulic cylinder. As a result, the outer peripheral surface 33a of the brake shoe 33 is pressed against the inner peripheral surface 31c of the drum 31, and the rotation speed of the drum 31 and thus the wheel 1 is reduced. That is, the brake mechanism 33 is moved from the separated position Pn to the sliding position along the outer surface 32a of the backing plate 32 by the operation of the pressing mechanism 34, and the drum 31 is slid by the outer peripheral surface 33a and the inner peripheral surface 31c. As a result, the wheel 1 is braked. The pressing mechanism 34 is not limited to the hydraulic type and may be another type such as an electric type. In the case of the electric type, the pressing mechanism 34 has a motor and a rotation/linear motion conversion mechanism that converts the rotation of the rotor of the motor into a linear motion, and, for example, between the front end portions 33b of the two brake shoes 33. Change the distance.

[Drive unit]
As shown in FIG. 1, the drive unit 40 includes a motor 41, a speed reduction mechanism 42, and a case 43.

As shown in FIG. 1, the motor 41 is positioned radially outward with respect to the rotation center Ax1. In the present embodiment, as an example, the motor 41 is positioned rearward with respect to the rotation center Ax1. Further, the motor 41 may be located radially outside the flange 12 a of the axle 12 and the knuckle 14.

The motor 41 has a stator 41a and a rotor 41b. The energization causes the rotor 41b to rotate around a rotation center Ax2 that is parallel to the rotation center Ax1. As shown in FIG. 2, the rotation center Ax2 is located rearward of the rotation center Ax1. The rotation center Ax2 does not have to be parallel to the rotation center Ax1. As the motor 41, various types and structures can be adopted.

Further, as shown in FIG. 1, the motor 41 is partially located inside the cylinder of the drum 31. In the present embodiment, a part of the output shaft 41b1, which is a part of the rotor 41b, is located inside the cylinder of the drum 31. Further, the motor 41 is located at least partially inside the cylinder of the wheel 1. In other words, at least a part of the motor 41 is located inside the inner peripheral surface 31c in the radial direction. The motor 41 may also be referred to as an in-wheel motor. The motor 41 is a motor for driving the vehicle.

The reduction mechanism 42 is at least partially housed in the cylinder of the drum 31. In other words, at least a part of the speed reduction mechanism 42 is located inside the inner peripheral surface 31c in the radial direction. In the present embodiment, as an example, the reduction mechanism 42 is entirely housed in the cylinder of the drum 31. The rotation of the rotor 41b is transmitted to the wheel 1 via the reduction mechanism 42. The reduction mechanism 42 has a plurality of gears 42a and 42b meshed with each other, and reduces the rotation of the rotor 41b. The gear 42a is fixed to the output shaft 41b1 and rotates around the rotation center Ax2. The gear 42b rotates with the rotation of the gear 42a. The gear 42b is fixed to the hub 11, and the hub 11 is coupled to the drum 31 and the wheel 1 via the bolt 1c. Therefore, the rotation of the rotor 41b is decelerated via the gears 42a and 42b and transmitted to the wheel 1.

The case 43 houses the motor 41 and the speed reduction mechanism 42. The case 43 has a motor cover 43a that covers the motor 41, a gear cover 43b that covers the reduction mechanism 42, and a partition wall 43c that separates the motor chamber that houses the motor 41 and the gear chamber that houses the reduction mechanism 42. ing. The partition wall 43c is provided with a through hole 43c1, and the output shaft 41b1 penetrates the through hole 43c1. The case 43 is made of, for example, a metal material such as an iron-based material or an aluminum alloy. The case 43 is composed of a plurality of integrated parts (divided bodies).

The gear cover 43b has a side wall 43b1 on the inner side in the vehicle width direction of the gear chamber. The side wall 43b1 and the partition wall 43c are continuous in a direction intersecting the axial direction, and constitute one wall 43d. The side wall 43b1 (wall 43d) is provided with a through hole 43b2, and the axle 12 penetrates the through hole 43b2. The portion of the side wall 43b1 where the through hole 43b2 is provided has a larger thickness than the other portions, and has higher rigidity and strength than the other portions. The wall 43d is fixed to the backing plate 32 in a state where the wall 43d is continuous with the backing plate 32 in a direction intersecting the axial direction or is overlapped with the backing plate 32 in the axial direction. That is, the wall 43 d that is a part of the case 43 forms a part of the backing plate 32.

Further, as shown in FIG. 2, the gear cover 43b has a cylindrical first portion 43b3 that covers the gear 42b and a semi-cylindrical second portion 43b4 that covers the gear 42a. The outer diameter of the semi-cylindrical portion of the second portion 43b4 is smaller than the outer diameter of the cylindrical portion of the first portion 43b3, and projects radially outward (rearward in this embodiment) from the first portion 43b3. The first portion 43b3 is located between the central portions of the two brake shoes 33, and the second portion 43b4 is located between the rear end portions 33c of the two brake shoes 33. Further, the protrusion 32d of the backing plate 32 is provided with a recess 32d1 that accommodates the second portion 43b4. The recess 32d1 is opened outward in the vehicle width direction and is opened inward in the radial direction.

[Wheel support structure]
As shown in FIG. 1, the hub 11 located substantially in the center of the wheel 1 has a cylindrical portion 11a and a flange 11b. The cylindrical portion 11a extends along the axial direction, and the flange 11b projects radially outward from the end portion of the cylindrical portion 11a on the outer side in the vehicle width direction. The hub 11 is provided with a through hole 11c that extends in the axial direction along the rotation center Ax1, and the axle 12 penetrates the through hole 11c. The axle 12 supports a cylindrical portion 11a of the hub 11 via a bearing 13 so as to be rotatable about a rotation center Ax1. A side wall 31a of the drum 31 and a side wall 1a of the wheel 1 are superposed on the side surface 11b1 on the outer side in the vehicle width direction of the flange 11b toward the outer side in the vehicle width direction, and these are integrally connected by a bolt 1c. The side surface 11b1 is referred to as a drum mounting surface, and the side surface 31a1 on the vehicle width direction outer side of the side wall 31a of the drum 31 is referred to as a wheel mounting surface. The side surface 11b1 and the side surface 31a1 intersect (or are orthogonal to) the direction parallel to the axial direction. The axle 12 is an example of a support member for the wheel 1.

[Connection structure with suspension]
FIG. 3 is a perspective view of the in-wheel structure 2 seen from the inside in the vehicle width direction with the wheel 1 and the drum 31 removed. As shown in FIG. 3, the knuckle 14 has a flange 14a, a first arm 14b, a second arm 14c, and a third arm 14d.

The flange 14a extends in a direction intersecting the axial direction and has a plate shape. Further, as shown in FIG. 1, the flange 14a is provided with a through hole 14a1, and the axle 12 penetrates the through hole 14a1. The flange 14a is fixed to the axle 12 and the wall 43d of the case 43. The knuckle 14 is an example of a support member for the wheel 1.

As shown in FIG. 3, the first arm 14b extends obliquely upward and inward in the vehicle width direction from the upper end of the flange 14a. The tip of the first arm 14b extends outside the cylinder of the wheel 1 and is located inside the vehicle width direction with respect to the end portion of the wheel 1 in the vehicle width direction. The strut 51 of the suspension 50 is connected to the tip of the first arm 14b. The suspension 50 is, for example, a MacPherson strut type suspension.

The second arm 14c extends inward in the vehicle width direction from the lower end of the flange 14a. The tip of the second arm 14c is located inside the cylinder of the wheel 1. The second arm 14c is rotatably connected to the lower arm 52 of the suspension 50 via a connecting member 71 such as a ball joint. The connection member 71 is an example of a first connection member.

The third arm 14d extends obliquely forward and inward in the vehicle width direction from the front end of the flange 14a. The tip of the third arm 14d is located inside the cylinder of the wheel 1. The third arm 14d is rotatably connected to the tie rod 61 of the steering mechanism 60 via a connecting member 72 such as a ball joint. The tie rod 61 is an example of a steering component, and the connecting member 72 is an example of a second connecting member.

[Part layout]
As shown in FIG. 3, the second arm 14c, the connecting member 71, and the motor 41 are arranged so as to be displaced from each other in the circumferential direction. The connecting member 71 that connects the second arm 14c of the knuckle 14 and the lower arm 52 of the suspension 50 is located inside the cylinder of the wheel 1. Therefore, by the configuration in which the second arm 14c and the connecting member 71 and the motor 41 are displaced from each other in the circumferential direction, the second arm 14c and the connecting member 71 are connected while ensuring the required functions of the second arm 14c and the connecting member 71. The motor 41 can be arranged at a position where it does not interfere with the member 71. The second arm 14c and the connecting member 71 are located below the rotation center Ax1 when viewed in the axial direction. Therefore, the motor 41 can be located at a position other than the position below the rotation center Ax when viewed in the axial direction.

Further, the motor 41, the first arm 14b, the third arm 14d, and the connecting member 72 are positioned so as to be displaced from each other in the circumferential direction. With such a configuration, while ensuring the required functions of the first arm 14b, the third arm 14d, and the connecting member 72, a position that does not interfere with the first arm 14b, the third arm 14d, and the connecting member 72, A motor 41 can be arranged.

Further, the motor 41 is positioned rearward with respect to the rotation center Ax1. The first arm 14b connected to the upper portion (upper portion or part) of the suspension 50 such as the strut 51 is located above the rotation center Ax1 when viewed in the axial direction. Further, as described above, the second arm 14c and the connecting member 71 connected to the lower portion (lower part or component) of the suspension 50 such as the lower arm 52 are closer to the rotation center Ax1 when viewed in the axial direction. Is also located below. Therefore, with the configuration in which the motor 41 is displaced to the rear side different from the upper side and the lower side with respect to the rotation center Ax1, a portion of the knuckle 14 that is connected to the suspension 50 (hereinafter, simply referred to as a connecting portion) and The motor 41 can be arranged at a position where it does not interfere with the connection site and the connection member 71 while ensuring the required function of the connection member 71 that connects the knuckle 14 and the suspension 50. In this case, the motor 41 is located rearward of the flange 12 a of the axle 12 and the knuckle 14. It should be noted that the same effect can be obtained by a configuration in which the motor 41 is positioned forward with respect to the rotation center Ax1. In this case, the motor 41 is positioned in front of the axle 12 and the flange 14a of the knuckle 14.

The motor 41 is located on the opposite side of the rotation center Ax1 from the third arm 14d and the connecting member 72. The connecting member 72 that connects the third arm 14d of the knuckle 14 and a component (steering component) of the steering mechanism 60, such as the tie rod 61, to the front or rear of the rotation center Ax1 when viewed in the axial direction. Is located. Therefore, the third arm 14d and the connecting member 72 are configured such that the motor 41 is located on the opposite side of the rotation center Ax1 from the third arm 14d and the connecting member 72, that is, behind or in front of the rotation center Ax1. It is possible to arrange the motor 41 at a position where it does not interfere with the third arm 14d and the connecting member 72 while ensuring the required performance by In the present embodiment, as an example, the tie rod 61 is located in front of the rotation center Ax1 when viewed in the axial direction, so that the motor 41 is located behind the rotation center Ax1. On the contrary, in the configuration in which the tie rod 61 is positioned rearward of the rotation center Ax1 when viewed in the axial direction, the motor 41 is positioned forward of the rotation center Ax1.

Further, as can be seen from FIGS. 1 to 3, the pressing mechanism 34 is located on the opposite side of the motor 41 with respect to the rotation center Ax1 when viewed in the axial direction. As shown in FIG. 1, the pressing mechanism 34 is located outside the outer surface 32 a of the backing plate 32 in the vehicle width direction. Further, in the present embodiment, the drive unit 40 is located partially outside the outer surface 32a of the backing plate 32 in the vehicle width direction. Therefore, if the motor 41 and the pressing mechanism 34 are arranged close to each other, it may be difficult to ensure the required function. In this respect, in the present embodiment, when viewed in the axial direction, the pressing mechanism 34 is located on the opposite side of the motor 41 with respect to the rotation center Ax1, so that while maintaining the required function of the pressing mechanism 34, The motor 41 can be arranged at a position where it does not interfere with the pressing mechanism 34.

As described above, in the present embodiment, the motor 41 is located radially outward from the rotation center Ax1 of the wheel 1. Further, at least a part of the motor 41 and the speed reduction mechanism 42 is located inside the cylinder of the drum 31. In other words, at least a part of the motor 41 and the speed reduction mechanism 42 is located inside the inner peripheral surface 31c of the drum 31 in the radial direction. With such a configuration, for example, the in-wheel structure 2 can be made smaller in the axial direction than a configuration in which the drum 31 and the drive unit 40 are arranged in series without partially overlapping in the axial direction.

Further, in the present embodiment, as described above, the motor 41 and the connecting member 71 (first connecting member) or the connecting member 72 (second connecting member) are positioned so as to be displaced from each other in the circumferential direction, or the motor 41 rotates. When the motor 41 and the pressing mechanism 34 are displaced rearward (or frontward) with respect to the center Ax1, or when viewed in the axial direction, the motor 41 and the pressing mechanism 34 are disposed on the opposite sides with respect to the rotation center Ax1. The interference between 41 and other parts is suppressed. As a result, for example, the motor 41 does not need to be downsized more than necessary, so that the required torque of the motor 41 is easily secured. Further, for example, since it is not necessary to consider the interference with the motor 41, it is easy to ensure the required function or performance of each component, and it is easy to increase the flexibility of the specifications and layout of each component.

Although the embodiments of the present invention have been illustrated above, the above embodiments are merely examples, and are not intended to limit the scope of the invention. The above-described embodiment can be implemented in various other forms, and various omissions, replacements, combinations, and changes can be made without departing from the spirit of the invention. In addition, specifications such as each configuration and shape (structure, type, direction, form, size, length, width, thickness, height, number, arrangement, position, material, etc.) may be changed as appropriate. Can be implemented.

For example, in the above-described embodiment, the vehicle driving motor is located behind the rotation center of the wheel, but the vehicle driving motor may be located radially displaced from the rotation center. That is, as long as the motor can avoid interference with other parts, when viewed in the axial direction, the motor is forward, forward and upward, upward, backward, with respect to the rotation center of the wheel, the axle, and the knuckle. The positions may be shifted upward, backward and downward, downward, downward and forward, and the like. Further, the suspension may be a suspension of a type different from the MacPherson strut type such as a multi-link type. Further, the reduction mechanism is not limited to the above embodiment, and the number, size, arrangement, etc. of gears can be appropriately changed and implemented, and may include a gear set such as a planetary gear, for example. A speed reducing mechanism different from a gear type such as a belt type may be used. Further, the present invention can be applied to wheels other than the steered wheels.

DESCRIPTION OF SYMBOLS 1... Wheel, 2... (For vehicle) in-wheel structure, 14... Knuckle (supporting member), 31... Drum, 31c... Inner peripheral surface, 33... Brake shoe (braking member), 34... Pressing mechanism, 40... Drive unit , 41... Motor, 41b... Rotor, 42... Reduction mechanism, 50... Suspension, 61... Tie rod (steering part), 71... Connection member (first connection member), 72... Connection member (second connection member), Ax1... Rotation center.

Claims (5)

A drum brake having a cylindrical drum,
A motor having a rotor, at least a part of which is housed in a cylinder of a cylindrical wheel and located radially away from the center of rotation of the wheel, and a reduction mechanism for reducing the rotation of the rotor and transmitting the rotation to the wheel. And a drive unit having
Equipped with
An in-wheel structure for a vehicle, wherein at least a part of at least one of the motor and the speed reduction mechanism is located inside a cylinder of the drum. The motor is configured to rotatably connect a support member that rotatably supports the wheel and a suspension, and to a first connecting member that is located in a cylinder of the wheel in a circumferential direction of a rotation center of the wheel. The vehicle in-wheel structure according to claim 1, wherein the in-wheel structure is offset from each other. The in-wheel structure for a vehicle according to claim 1 or 2, wherein the motor is displaced from the center of rotation of the wheel toward the front side or the rear side of the vehicle. The motor is located on the opposite side of a rotation center of the wheel from a second connecting member that rotatably connects a supporting member that rotatably supports the wheel and a steering component. The vehicle in-wheel structure described in. The drum brake further includes a pressing mechanism that is located on the opposite side of the motor with respect to the rotation center when viewed in the axial direction of the rotation center of the wheel and that presses the braking member against the inner peripheral surface of the drum. The in-wheel structure for a vehicle according to any one of claims 1 to 4.

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