JP2007307996A - Wheel motor suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel motor suspension device capable of compatibly realizing the dynamic damper function and the supporting function of the wheel motor rotating direction, and adequately realizing the vertical rigidity and the torsional rigidity. <P>SOLUTION: Connection parts 51a, 51b of a first leaf spring 5a and a second leaf spring 5b are located on the position different from the position on a line to connect two supporting parts 45 of an axle 4 to each other while an in-wheel motor 6 is assembled to the axle 4 via the leaf springs 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a suspension device for a wheel motor driven by a motor attached to the wheel.

As this type of technology, the technology described in Patent Document 1 is disclosed. In this publication, a rubber mount is provided between the wheel support device and the in-wheel motor with the direction of vibration input from the tire as an axis. A dynamic damper is formed with an in-wheel motor as a mass and a rubber mount as a spring to suppress vibration under the spring. Further, the rubber mount supports a rotational reaction force applied to the in-wheel motor by the rotation of the wheel.
JP 2005-126073 A

  Set the stiffness (vertical stiffness) in the vibration direction input from the tire to an appropriate value so that the dynamic natural frequency matches the unsprung vibration frequency with respect to the stiffness of the rubber mount, and add to the wheel motor In order to support the rotational reaction force, setting the rigidity (torsional rigidity) in the rotation direction of the wheel motor to an appropriate value, the above two characteristics are required. Generally, the torsional rigidity tends to be set higher to improve the transmission efficiency of the driving force of the wheel motor, but the vertical rigidity is small compared to the torsional rigidity because the unsprung vibration frequency is often low. Often value. However, with a rubber bush, it has been difficult to set both vertical rigidity and torsional rigidity to optimum values.

  The present invention has been made paying attention to the above problems, and the object is to optimize the vertical and torsional rigidity that achieves both the dynamic damper function and the support function in the rotational direction of the wheel motor. An object of the present invention is to provide a wheel motor suspension device that can perform the above-described operation.

  In order to achieve the above object, in the wheel motor suspension of the present invention, an axle that rotatably supports the tire wheel, a wheel motor that generates a driving force of the tire wheel, an elastic body that couples the axle and the wheel motor, The elastic body includes an extending portion extending from the axle toward the wheel motor, and a straight line connecting the axle-side end portion of the extending portion and the wheel motor-side end portion is provided on the wheel. An interval is provided between the motor and the center of rotation, and the straight line is inclined with respect to the vehicle vertical direction.

  Therefore, in the wheel motor suspension device of the present invention, even if the vertical rigidity is set as the elastic body of the dynamic damper, the torsional rigidity can be set sufficiently larger than the vertical rigidity. Therefore, it is possible to optimize the vertical rigidity and the torsional rigidity that achieve both the dynamic damper function and the support function in the rotation direction of the wheel motor.

  Hereinafter, the best mode for realizing the wheel motor suspension of the present invention will be described based on the first embodiment.

  First, the configuration will be described.

  FIG. 1 is a view of the drive wheel 1 as seen from the inside of the vehicle, and FIG. 2 is a view of the drive wheel 1 as seen from above. FIG. 3 is a perspective view of the in-wheel motor (wheel motor) 6 attached to the axle 4.

  The drive wheel 1 is suspended by a tire 2, a tire wheel 3 to which the tire 2 is attached, an axle 4 that instructs the tire wheel 3 to rotate freely, and a axle 4 via a leaf spring (elastic body) 5. And an in-wheel motor 6 that generates one driving force.

  The tire wheel 3 includes a disk surface 3a supported by the axle 4 and a rim surface 3b extending from the disk surface 3a toward the vehicle inner side (vehicle width direction inner side).

  The in-wheel motor 6 is formed with a smaller diameter than the tire wheel 3 and is disposed inside the outer shape of the tire wheel 3 in a vehicle side view. A part of the in-wheel motor 6 is disposed on the vehicle outer side with respect to the vehicle inner end portion of the rim surface 3b. That is, a part of the in-wheel motor 6 is inserted and supported in a space surrounded by the disk surface 3 a and the rim surface 3 b of the tire wheel 3.

  The outer shape of the in-wheel motor 6 is a shape in which two cylinders having different diameters with respect to the rotation axis are connected to each other at the bottom surface, and the smaller diameter is the smaller diameter portion 60 and the larger diameter portion is larger than the smaller diameter portion 60. 61.

  The axle 4 is formed from an inner diameter surface 40 formed so that the small diameter portion 60 of the in-wheel motor 6 can be inserted, and an outer diameter surface 41 formed so as to substantially match the diameter of the large diameter portion 61 of the in-wheel motor 6. It has the cylindrical part 43 which is a donut-shaped cylindrical member. The arm portion 44 is provided so as to be point-symmetric with respect to the axis toward the radially outer side of the cylindrical portion 43. A support portion (elastic body support portion) 45 for supporting the leaf spring 5 is provided in the vicinity of the opposite end portion of the cylindrical portion 43 of the arm portion 44, and this support portion 45 is formed in a cylindrical shape protruding in the axial direction. The

  The leaf spring 5 includes a first leaf spring (first elastic body) 5 a disposed on the vehicle vertical direction upper side with respect to the rotation center of the in-wheel motor 6 and a vehicle vertical direction lower side with respect to the rotation center of the in-wheel motor 6. And a second leaf spring (second elastic body) 5b. The first leaf spring 5a and the second leaf spring 5b have insertion portions 50a and 50b inserted into the support portion 45 of the axle 4 at one end and a connection portion (in-wheel motor connection) connected to the in-wheel motor 6 at the other end. Part) 51a, 51b and extending parts 52a, 52b extending between the inserting parts 50a, 50b and the connecting parts 51a, 51b.

  The insertion portions 50 a and 50 b are formed with insertion holes that are inserted into the support portions 45 of the axle 4. The insertion portions 50 a and 50 b are inserted into the support portion 45 of the axle 4 and are fastened to the axle 4 by bolts 70.

  The connecting portions 51a and 51b are formed in an arc shape so as to be in contact with the shape of the small diameter portion 60 of the in-wheel motor 6. Bolts 71 are inserted into through holes formed in the connecting portions 51a and 51b, and the first plate spring 5a and the second plate spring 5b and the in-wheel motor 6 are fastened.

  In a state where the in-wheel motor 6 is assembled to the axle 4 via the leaf springs 5 (first leaf spring 5a, second leaf spring 5b), a line segment connecting the two support portions 45 of the axle 4 (dotted line in FIG. 1). A) The connecting portions 51a and 51b of the first leaf spring 5a and the second leaf spring 5b are located at positions different from the above.

  That is, the line segment (dotted line B in FIG. 1) connecting the insertion portions 50a and 50b of the first leaf spring 5a and the second leaf spring 5b and the connection portions 51a and 51b is separated from the rotation center O of the in-wheel motor 6. It is formed so that there is a (distance). The straight line connecting the end portions on the insertion portions 50a, 50b side of the extending portions 52a, 52b of the first leaf spring 5a and the second leaf spring 5b and the end portions on the connection portions 51a, 51b side is the rotation of the in-wheel motor 6. There is an interval from the center O, and this straight line is inclined with respect to the vehicle vertical direction.

  Further, the connecting portions 51a and 51b of the first leaf spring 5a and the second leaf spring 5b are arranged so as to be positioned on the direction in which the driving wheel 1 vibrates during traveling (dotted line C in FIG. 1). A link mechanism is constituted by 5a, the second leaf spring 5b, and the in-wheel motor 6.

  Next, the operation will be described.

  In the in-wheel motor suspension device of the first embodiment, a dynamic damper is formed by using the in-wheel motor 6 as a mass and the leaf spring 5 as a spring against vibrations (vertical vibrations) while the drive wheels 1 are traveling. On the other hand, the in-wheel motor 6 is supported against the rotational reaction force of the in-wheel motor 6 against vibration (torsional vibration) caused by the rotational reaction force of the in-wheel motor 6.

  Therefore, it is necessary to adjust the rigidity (vertical rigidity) of the leaf spring 5 with respect to the vertical vibration according to the vibration frequency of the driving wheel 1 during traveling. Further, in order to prevent the in-wheel motor 6 itself from rotating, the rigidity (torsional rigidity) of the leaf spring 5 against torsional vibration needs to be set large. That is, although the vertical stiffness of the leaf spring 5 needs to be set to be moderately small, the torsional stiffness needs to be set sufficiently larger than the vertical stiffness.

  FIG. 4 shows a state of the leaf spring 5 due to vertical vibration, and FIG. 5 is a view showing a state of the leaf spring 5 due to torsional vibration.

  With respect to the vertical vibration, as shown in FIG. 4, the extending portions 52a and 52b of the first leaf spring 5a and the second leaf spring 5b are deformed in the bending direction. On the other hand, with respect to torsional vibration, the extending portions 52a and 52b of the first leaf spring 5a and the second leaf spring 5b are deformed in the axial direction as shown in FIG.

  In the first embodiment, the extension portions 52a and 52b of the first leaf spring 5a and the second leaf spring 5b are deformed in the bending direction with respect to the vertical vibration, and the first leaf spring 5a and the second leaf spring with respect to the torsional vibration. Since the extending portions 52a and 52b of the leaf spring 5b are deformed in the axial direction, the torsional rigidity can be set sufficiently larger than the vertical rigidity of the leaf spring 5.

[Comparison with conventional products]
Next, the operation will be described by comparing the conventional and the in-wheel motor suspension of the first embodiment.

  FIG. 6 is a schematic diagram of a conventional in-wheel motor suspension device, and FIG. 7 is a schematic diagram of the in-wheel motor suspension device of the first embodiment.

  As shown in FIG. 6, in the conventional in-wheel motor suspension apparatus, the in-wheel motor 6 is supported by four elastic bodies 8 provided on the upper and lower sides. Each of the four elastic bodies 8 has a spring constant kz in the axial direction (coincident with the vertical vibration direction). Further, it is assumed that the four elastic bodies 8 are arranged at a distance L in the left-right direction with respect to the rotation center O of the in-wheel motor 6.

The sum Kz of the vertical rigidity of the four elastic bodies 8 is expressed by the following equation (1).
Kz = 4 · kz (1)
The sum Kφ of the torsional rigidity of the four elastic bodies 8 is expressed by the following equation (2).
Kφ = 4 · kz · L ² (2)
From the equations (1) and (2), the rigidity ratio (Kφ / Kz) is expressed by the following equation (3).
Kφ / Kz = L ² (3)

  As shown in FIG. 7, in the in-wheel motor suspension apparatus according to the first embodiment, the insertion portions 50 a and 50 b of the first leaf spring 5 a and the second leaf spring 5 b are lateral to the rotation center O of the in-wheel motor 6. And a distance L in the vertical direction. The plate thicknesses of the extending portions 52a and 52b are h, the plate width is b, and the Young's modulus is E.

The sum Kz of vertical rigidity of the leaf spring 5 is expressed by the following equation (4).
Kz = (E ・ b ・ h ³ ) / (2 ・ L ³ ) (4)
Further, the sum Kφ of the torsional rigidity of the leaf spring 5 is expressed by the following equation (5).
Kφ = (2 ・ E ・ b ・ h ・ r ² ) / L (5)
From the equations (4) and (5), the rigidity ratio (Kφ / Kz) is expressed by the following equation (6).
Kφ / Kz = 4 (L ・ r / h) ² (6)

The rigidity ratio (Kφ / Kz) indicates the torsional rigidity relative to the vertical rigidity. That is, as the stiffness ratio (Kφ / Kz) is larger, the torsional stiffness kφ can be set larger than the vertical stiffness Kz. In the equations (1) and (4), if the vertical stiffness of the elastic body 8 and the leaf spring 5 is set to be equal to constitute a dynamic damper, the torsional stiffness of the leaf spring 5 is obtained from the equations (3) and (6). It can be seen that the rigidity of the elastic body 8 is 4 (r / h) ² times the torsional rigidity. Usually, since the relationship [h << r] is established, the torsional rigidity of the leaf spring 5 is sufficiently larger than the torsional rigidity of the elastic body 8.

  As described above, in a state where the in-wheel motor 6 is assembled to the axle 4 via the leaf spring 5, the first leaf spring 5a and the first leaf spring 5a are located at positions different from the line segment connecting the two support portions 45 of the axle 4. The connection portions 51a and 51b of the two leaf springs 5b are positioned. That is, the line segment connecting the insertion portions 50a and 50b of the first leaf spring 5a and the second leaf spring 5b and the connection portions 51a and 51b is separated from the rotation center O of the in-wheel motor 6 (there is a distance). Formed. The straight line connecting the end portions on the insertion portions 50a, 50b side of the extending portions 52a, 52b of the first leaf spring 5a and the second leaf spring 5b and the end portions on the connection portions 51a, 51b side is the rotation of the in-wheel motor 6. There is an interval from the center O, and this straight line is inclined with respect to the vehicle vertical direction.

  Therefore, even if the vertical rigidity is set as the elastic body of the dynamic damper, the torsional rigidity can be set sufficiently large. Therefore, it is possible to optimize the vertical rigidity and the torsional rigidity that achieve both the dynamic damper function and the support function in the rotational direction of the in-wheel motor 6.

  Further, the connection portions 51a and 51b of the first leaf spring 5a and the second leaf spring 5b are formed in an arc shape so as to be in contact with the shape of the small-diameter portion 60 of the in-wheel motor 6, and the leaf spring 5 and the in-wheel motor 6 is directly connected by a bolt 71.

  Therefore, it is not necessary to use a bracket or the like for attaching the in-wheel motor 6 to the leaf spring 5. Therefore, since it is possible to avoid a decrease in mounting rigidity due to the presence of a bracket or the like, torsional rigidity can be ensured.

  In addition, the leaf spring 5 is disposed on the vehicle vertical direction upper side with respect to the rotation center of the in-wheel motor 6, and the plate spring 5 is disposed on the vehicle vertical direction lower side with respect to the rotation center of the in-wheel motor 6. It comprised from the 2 leaf | plate spring 5b.

  Therefore, the first plate spring 5a and the second plate spring 5b can support the in-wheel motor 6 at a point away from the center of rotation, and the support rigidity is high against the rotational reaction force of the in-wheel motor 6. can do.

  Moreover, the in-wheel motor 6 was arrange | positioned inside the external shape of the tire wheel 3 in the vehicle side view.

  Therefore, the in-wheel motor 6 can be inserted into the tire wheel 3, and the vehicle mountability of the in-wheel motor 6 can be improved.

  Further, a part of the in-wheel motor 6 is disposed on the vehicle outer side with respect to the vehicle inner end portion of the rim surface 3b.

  Therefore, a part of the in-wheel motor 6 is inserted and supported in a space surrounded by the disk surface 3a and the rim surface 3b of the tire wheel 3, and the in-wheel motor 6 can be mounted on the vehicle.

  Further, the leaf spring 5 is supported by inserting the insertion portions 50 a and 50 b into the support portion 45 of the axle 4.

  Therefore, it is not necessary to use a bracket or the like that attaches the leaf spring 5 to the axle 4, so that the number of parts can be reduced.

  Next, the effect of the present embodiment will be described.

  (1) In a state where the in-wheel motor 6 (wheel motor) is assembled to the axle 4 via the leaf spring 5 (elastic body), the first position is different from the position on the line connecting the two support portions 45 of the axle 4. The connection portions 51a and 51b of the first leaf spring 5a and the second leaf spring 5b are positioned. That is, the line segment connecting the insertion portions 50a and 50b of the first leaf spring 5a and the second leaf spring 5b and the connection portions 51a and 51b is separated from the rotation center O of the in-wheel motor 6 (there is a distance). Formed. The straight line connecting the end portions on the insertion portions 50a, 50b side of the extending portions 52a, 52b of the first leaf spring 5a and the second leaf spring 5b and the end portions on the connection portions 51a, 51b side is the rotation of the in-wheel motor 6. There is an interval from the center O, and this straight line is inclined with respect to the vehicle vertical direction.

  Therefore, even if the vertical rigidity is set as the elastic body of the dynamic damper, the torsional rigidity can be set sufficiently large. Therefore, it is possible to optimize the vertical rigidity and the torsional rigidity that achieve both the dynamic damper function and the support function in the rotational direction of the in-wheel motor.

  (2) The connecting portions 51a and 51b of the first leaf spring 5a and the second leaf spring 5b are formed in an arc shape so as to be in contact with the shape of the small diameter portion 60 of the in-wheel motor 6, and the leaf spring 5 and the in-wheel. The motor 6 is directly connected with the bolt 71.

  Therefore, it is not necessary to use a bracket or the like for attaching the in-wheel motor 6 to the leaf spring 5. Therefore, since it is possible to avoid a decrease in mounting rigidity due to the presence of a bracket or the like, torsional rigidity can be ensured.

  (3) A first leaf spring 5a (first elastic body) in which the spring 5 is arranged on the upper side in the vehicle vertical direction with respect to the rotation center of the in-wheel motor 6, and the vehicle vertical direction with respect to the rotation center of the in-wheel motor 6. It comprised from the 2nd leaf | plate spring 5b (2nd elastic body) arrange | positioned on the lower side.

  Therefore, the first plate spring 5a and the second plate spring 5b can support the in-wheel motor 6 at a point away from the center of rotation, and the support rigidity is high against the rotational reaction force of the in-wheel motor 6. can do.

  (4) The in-wheel motor 6 is disposed inside the outer shape of the tire wheel 3 in a vehicle side view.

  Therefore, the in-wheel motor 6 can be inserted into the tire wheel 3, and the vehicle mountability of the in-wheel motor 6 can be improved.

  (5) A part of the in-wheel motor 6 is disposed on the vehicle outer side with respect to the vehicle inner end portion of the rim surface 3b.

  Therefore, a part of the in-wheel motor 6 is inserted and supported in a space surrounded by the disk surface 3a and the rim surface 3b of the tire wheel 3, and the in-wheel motor 6 can be mounted on the vehicle.

  (6) The leaf spring 5 is supported by inserting the insertion portions 50 a and 50 b into the support portion 45 of the axle 4.

  Therefore, it is not necessary to use a bracket or the like that attaches the leaf spring 5 to the axle 4, so that the number of parts can be reduced.

(Other examples)
The best mode for carrying out the present invention has been described based on the first embodiment. However, the specific configuration of the present invention is not limited to the first embodiment and does not depart from the gist of the present invention. Any change in the design of the range is included in the present invention.

  In the first embodiment, the leaf spring 5 is constituted by the separate first leaf spring 5a and second leaf spring 5b. However, as shown in FIG. 8, the first leaf spring 5a and the second leaf spring 5b are connected to each other. It may be formed integrally by connecting at 51.

  By forming in this way, the leaf spring 5 is integrally formed, and the connection portion 51 extends along the side surface of the in-wheel motor 6 from the upper side to the lower side in the vehicle vertical direction with respect to the rotation center of the in-wheel motor. Can be formed in contact with each other. Therefore, the support rigidity of the in-wheel motor 6 by the leaf spring 5 can be increased.

  Further, the shape of the leaf spring 5 is a line segment connecting the two support portions 45 of the axle 4 with the in-wheel motor 6 assembled to the axle 4 via the first leaf spring 5a and the second leaf spring 5b. As long as the connecting portions 51a and 51b of the first leaf spring 5a and the second leaf spring 5b are located at different positions. Alternatively, the shape of the leaf spring 5 is a straight line connecting the end portions on the insertion portions 50a, 50b side of the extending portions 52a, 52b of the first leaf spring 5a and the second leaf spring 5b and the end portions on the connection portions 51a, 51b side. Any shape may be used as long as it has an interval from the rotation center O of the in-wheel motor 6 and has an inclination with respect to the vehicle vertical direction.

  If it is the shape of the leaf | plate spring 5 as mentioned above, it will not specifically limit. Therefore, you may make it use the leaf | plate spring 5 supported at both ends, as shown in FIG. Even if it is the shape of the leaf | plate spring 5 as shown in FIG. 9, the effect similar to Example 1 can be acquired.

  Further, as shown in FIG. 10, a torsion bush 9 may be provided between the support portion 45 of the axle 4 and the insertion portions 50 a and 50 b of the leaf spring 5.

  By adding the torsion bush 9, it is possible to increase the degree of freedom in setting the vertical and torsional rigidity. Further, vibration and noise transmission from the in-wheel motor 6 to the axle 4 can be suppressed.

  In the first embodiment, the in-wheel motor 6 in which a part of the motor is inserted into the wheel 3 is used. However, the motor has an outer shape larger than that of the wheel 3 and is inserted into the wheel 3. No motor may be used.

It is the figure which looked at the drive wheel of Example 1 from the vehicle inside. It is the figure which looked at the driving wheel of Example 1 from the upper part. It is an attachment perspective view to the axle of the in-wheel motor of Example 1. It is a figure which shows the mode of the leaf | plate spring by the vertical vibration of Example 1. FIG. It is a figure which shows the mode of the leaf | plate spring by the torsional vibration of Example 1. FIG. It is a schematic diagram of the conventional in-wheel motor suspension apparatus. It is a schematic diagram of the in-wheel motor suspension apparatus of Example 1. It is a figure which shows the shape of the leaf | plate spring of another Example. It is a figure which shows the shape of the leaf | plate spring of another Example. It is an attachment perspective view to the axle of the in-wheel motor of other examples.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive wheel 3 Tire wheel 4 Axle 5 Leaf spring 5a 1st leaf spring 5b 2nd leaf spring 6 In-wheel motor 45 Support part 50a, 50b Insertion part 51a, 51b Connection part 52a, 52b Extension part

Claims (6)

An axle that rotatably supports the tire wheel;
A wheel motor for generating a driving force of the tire wheel;
An elastic body for coupling the axle and the wheel motor;
In the wheel motor suspension with
The elastic body includes an extending portion extending from the axle toward the wheel motor, and a straight line connecting the axle-side end portion and the wheel motor-side end portion of the extending portion is a rotation center of the wheel motor. A wheel motor suspension device, characterized in that the straight line has an inclination with respect to a vehicle vertical direction. The wheel motor suspension device according to claim 1,
The wheel motor suspension device according to claim 1, wherein the elastic body is formed with a wheel motor connecting portion connected to the wheel motor along an outer shape of the wheel motor. In the wheel motor suspension device according to claim 1 or 2,
The elastic body includes a first elastic body arranged on the vehicle vertical direction upper side with respect to the rotation center of the wheel motor, and a second elastic body arranged on the vehicle vertical direction lower side with respect to the rotation center of the wheel motor. A wheel motor suspension system. In the wheel motor suspension device according to claim 3,
The wheel motor suspension device, wherein the elastic body is integrally formed by connecting the first elastic body and the second elastic body at the wheel motor connecting portion. In the wheel motor suspension device according to any one of claims 1 to 4,
The wheel motor suspension device, wherein the wheel motor is disposed inside an outer shape of the tire wheel in a side view of the vehicle. In the wheel motor suspension device according to claim 5,
The tire wheel includes a disk surface supported by the axle, and a rim surface extending from the disk surface toward the inside in the vehicle width direction,
At least a part of the wheel motor is disposed on the outer side in the vehicle width direction with respect to the end portion on the inner side in the vehicle width direction of the rim surface in a vehicle front view and a vehicle top view. .

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