JP2019010970A - De dion type suspension device of vehicle - Google Patents

Abstract

To provide a de Dion type suspension device of a vehicle such as an electric commercial car capable of further improving reliability.SOLUTION: A de Dion type suspension device 1 of a vehicle is composed of: first hollow members 12a, 12b which store drive shafts 6a, 6b in vehicle wheels 8a, 8b; a pair of second hollow members 14a, 14b which are joined with the first hollow members 12a, 12b, store the drive shafts 6a, 6b, and are connected to elastic bodies 16a, 16b for suspending bodies 10a, 10b of the vehicle; and a third hollow member. The de Dion type suspension device 1 includes an axle pipe 18 which couples the pair of the second hollow members 14a, 14b to support the pair of the vehicle wheels 8a, 8b. Outer surfaces of the second hollow members 14a, 14b continuing to joint surfaces 46a between the first hollow members 12a, 12b and the second hollow members 14a, 14b are made to be continuous surfaces 48 without corner portions.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a dodion-type suspension device for a vehicle, and more particularly to a dodion-type suspension device suitable for an electric commercial vehicle.

  Conventionally, in the field of passenger cars, it is known to use, for example, a dodion type suspension device as a suspension device for an electric vehicle (see, for example, Patent Document 1). By applying such a suspension device, the unsprung weight can be made lighter than the axle type, so that the steering stability of the vehicle can be improved.

JP 2000-25440 A

  In recent years, electric commercial vehicles such as electric trucks without an internal combustion engine have been developed in the field of commercial vehicles such as trucks from the viewpoint of reducing environmental impact. However, such an electric commercial vehicle has a larger vehicle weight than a passenger vehicle, and the vehicle weight increases more particularly when cargo is loaded. Therefore, since a very large input is generated in the suspension device, higher reliability is required as compared with the suspension device for passenger cars.

  The present invention has been made to solve at least a part of such problems, and an object of the present invention is to provide a dodion-type suspension device for a vehicle such as an electric commercial vehicle that can further improve reliability. It is to provide.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

  The vehicle dodion type suspension device according to this application example includes a power transmission mechanism that transmits a driving force of a motor mounted on the vehicle, and a pair of wheels that transmit the driving force transmitted to the power transmission mechanism to a pair of wheels, respectively. A dodion type suspension device for a vehicle comprising a drive shaft, a first hollow member for housing the drive shaft in a wheel, and being joined to the first hollow member, housing the drive shaft, and suspending the vehicle body A pair of second hollow members connected to the elastic body and a third hollow member, and an axle pipe supporting the pair of wheels by connecting the pair of second hollow members, the first hollow The outer surface of the second hollow member continuous to the joint surface between the member and the second hollow member is formed as a continuous surface having no corners.

  By forming such a continuous surface, the first hollow member and the second hollow member are connected in a continuous and smooth outer surface shape without a step. For example, when the outer surface of the second hollow member is conventionally formed with a stepped tapered surface, excessive stress concentration occurs on the stepped portion and the joint surface. However, by the formation of the continuous surface of the present embodiment, the stress concentration is relaxed, and the stress of the second hollow member and the joint surface can be reduced.

  According to the vehicle dodion type suspension apparatus of the present invention using the application example, it is possible to provide a vehicle dodion type suspension apparatus capable of further improving the reliability.

It is a top view which shows the outline of the dodion-type suspension apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the principal part of the hollow structure of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a top view schematically showing a dodion suspension according to an embodiment of the present invention. The dodion type suspension device 1 (hereinafter also simply referred to as a suspension device) is a rear suspension provided at the rear of an electric commercial vehicle (hereinafter also referred to as a vehicle) such as an electric truck, for example.

  The vehicle is equipped with a motor 2 as a traveling drive source. The driving force of the motor 2 is a power transmission mechanism 4 including a reduction gear composed of a plurality of reduction gears and a differential gear connected to the reduction gear, and a pair of drive shafts. The signals are transmitted to the left and right wheels 8a and 8b through 6a and 6b, respectively. The wheels 8a and 8b are supported by side rails (vehicle bodies) 10a and 10b extending across the vehicle longitudinal direction Y via the suspension device 1. The motor 2 and the power transmission mechanism 4 are supported on the vehicle body side via a frame (not shown) and side rails 10a and 10b.

  The suspension device 1 includes a pair of spindles (first hollow members) 12a and 12b, a pair of saddles (second hollow members) 14a and 14b, a pair of leaf springs (elastic bodies) 16a and 16b, and an axle pipe (third hollow). Member) and the like. The spindles 12a and 12b are a pair of hollow members provided at both ends in the vehicle width direction X, and are connected to the hubs 20a and 20b, respectively. The hubs 20a and 20b are attached to wheels (not shown) provided in the wheels 8a and 8b.

  The outer ends of the drive shafts 6a and 6b in the vehicle width direction X are formed of flexible joints and are respectively accommodated in the saddles 14a and 14b described later. In each saddle 14a, 14b, the outer ends of the drive shafts 6a, 6b are connected to the drive shafts 6a, 6b accommodated in the spindles 12a, 12b, and the hubs 20a, 20b are connected via the drive shafts 6a, 6b. Connected to The drive shafts 6a and 6b accommodated in the spindles 12a and 12b are supported by the saddles 14a and 14b via bearings (not shown).

  On the other hand, the inner ends of the drive shafts 6a and 6b in the vehicle width direction X are also composed of flexible joints 22a and 22b, and are connected to the gear of the power transmission mechanism 4. Moreover, a part of flexible joints 22a and 22b is covered with boots 24a and 24b.

  The saddles 14a and 14b are a pair of hollow members that are joined to the inner ends of the spindles 12a and 12b in the vehicle width direction X. Each of the saddles 14a and 14b forms a pair of hollow structures 26a and 26b communicated with the spindles 12a and 12b. The drive shafts 6a and 6b are accommodated in the hollow structures 26a and 26b.

  The leaf springs 16a and 16b extend in the vehicle longitudinal direction Y, and elastically support the vehicle body by suspending the side rails 10a and 10b. The lower surfaces of the leaf springs 16a and 16b are placed on the upper surfaces of the saddles 14a and 14b, and are fixed to the saddles 14a and 14b with U-bolts or the like.

  The axle pipe 18 is a cylindrical hollow member whose both ends are connected to the rear portions of the saddles 14a and 14b in the vehicle front-rear direction Y. The axle pipe 18 communicates with the hollow structures 26a and 26b so that the axle structure 28 is connected. Forming. The axle pipe 18 is elastically supported by the side rails 10a and 10b via a shock absorber (not shown), and supports the wheels 8a and 8b while ensuring the rigidity of the axle structure 28.

  The axle pipe 18 includes end portions 18a and 18b and a straight portion 18c disposed between the end portions 18a and 18b. The end portions 18a and 18b are connected to the rear portions of the saddles 14a and 14b in the vehicle longitudinal direction Y, respectively. The straight portion 18c extends in the vehicle width direction X, is disposed between the end portions 18a and 18b, and is joined to the end portions 18a and 18b by welding or the like.

  The end portions 18a and 18b have a shape curved from the vehicle longitudinal direction Y toward the vehicle width direction X. Thereby, it is avoided that the axle pipe 18 and the axle structure 28 interfere with the power transmission mechanism 4 at the rear part of the vehicle.

  As described above, in the suspension device 1 described above, the leaf springs 16a and 16b suspend and elastically support the drive shafts 6a and 6b, the axle structure 28, and the wheels 8a and 8b at their lower portions. Yes.

  FIG. 2 is a cross-sectional view showing a main part of the hollow structure 26a. Since the hollow structure 26b has the same structure, the illustration and description of the hollow structure 26b are omitted, and the hollow structure 26a will be described below as a representative. The spindle 12a has a cylindrical shape having a hollow portion 30, and gradually increases in diameter from the first opening end 32 and the first opening end 32 in order from the outer side (wheel 8a side) to the inner side in the vehicle width direction X. The taper part 34, the flange part 36 which continues to the taper part 34, and the 2nd opening end 38 formed in the saddle 14a side of the flange part 36 are provided.

  On the other hand, the saddle 14 a includes a main body portion 40 to which the leaf spring 16 a is fixed, and a connecting portion 42 that extends from the main body portion 40 in the vehicle width direction X and is connected to the second opening end 38. . The connecting portion 42 of the saddle 14a has a cylindrical shape having a hollow portion 44, and the spindle 12a and the saddle 14a are connected to each other by welding the opening end 42a of the connecting portion 42 of the saddle 14a to the second opening end 38 of the spindle 12a. Joined at the weld 46.

  Here, in the present embodiment, the outer surface of the connecting portion 42 of the saddle 14 a is formed as a continuous surface 48 having no corners until reaching the welding surface (joining surface) 46 a of the welding portion 46. As shown in FIG. 2, the continuous surface 48 has one smooth curved portion 48 a that is convex toward the hollow portion 44 with a predetermined radius of curvature R. The curved portion 48a is gradually reduced in diameter from the main body portion 40 of the saddle 14a and smoothly connected to the flat portion 48b of the continuous surface 48 without corners.

  By forming such a continuous surface 48, the spindle 12a and the saddle 14a are connected in a continuous and smooth outer shape with no step. Further, in the case of the present embodiment, as a result of considering the optimum radius of curvature R of the curved portion 48a, the outer diameter of the second opening end 38 of the spindle 12a and the outer diameter of the opening end 42a of the saddle 14a are compared with the conventional one. About 10% larger. As a result, the outer diameter of the hollow structure 26a in the vicinity of the weld 46 is increased, and the section modulus of the hollow structure 26a is increased.

  For example, the case where the outer surface of the connection part 42 of the saddle 14a is conventionally formed with a plurality of tapered surfaces connected with a step is assumed. In this case, a very large input is generated in the saddle 14a because the load caused by the load amount via the leaf spring 16a and the road surface load from the wheels 8a and 8b are concentrated. As a result, excessive stress concentration occurs on the stepped portion of the connecting portion 42 and the welded surface 46a of the welded portion 46.

  However, in the present embodiment, the stress concentration at the connecting portion 42 and the welded portion 46 of the saddle 14a is suppressed by the formation of the continuous surface 48 and the increase in the section modulus of the hollow structure 26a. Specifically, as a result of the stress analysis such as CAE of the connecting portion 42 and the welded portion 46, it has been found that the present embodiment can reduce the stress by about 40% compared to the conventional hollow structure 26a. Yes.

  Therefore, the reliability of the suspension device 1 is increased even when a large input is generated in the saddle 14a of the suspension device 1, particularly in an electric commercial vehicle or the like that has a larger vehicle weight than a passenger car and particularly increases in the vehicle weight when cargo is loaded. Can be improved. Of course, the same effect can be obtained for the hollow structure 26b, and the same applies to the following description.

  Although the description of the embodiment of the suspension device 1 according to the present invention is finished above, the embodiment is not limited to the above embodiment.

  For example, the axle pipe 18 is not limited to a cylindrical shape, and may be a rectangular tube shape as long as the rigidity of the axle structure 28 can be secured. A solid member such as an axle beam may be used instead of the hollow axle pipe 18. Further, the shape of the connecting portion 42 of the spindle 12a and the saddle 14a is not limited to the shape described in the above embodiment.

  Further, the continuous surface 48 formed on the outer surface of the connecting portion 42 of the saddle 14a does not have a corner portion, and is not limited to the above-described embodiment as long as the stress concentration on the connecting portion 42 can be suppressed and the stress can be reduced. . For example, the continuous surface 48 is not limited to one curved portion 48a, and may be formed by smoothly connecting a plurality of curved portions having different radii of curvature, and the flat surface 48b is not necessarily provided.

  Moreover, you may form the inner surface of the connection part 42 of the saddle 14a as a continuous surface which does not have a corner | angular part until it reaches the welding part 46 similarly to an outer surface. In this case, it is possible to further reduce the stress of the hollow structure 26a.

  Further, if the inner surface of the connecting portion 42 of the saddle 14a is a continuous surface similar to the outer surface and the inner diameter of the connecting portion 42 is increased as compared with the conventional one, while further reducing the stress of the hollow structure 26a, It is also possible to realize further thinning of the hollow structure 26a and thus lightening.

  In addition, the suspension device 1 of the present embodiment is not limited to an electric commercial vehicle such as an electric truck, and it is needless to say that the above-described operation and effect can be obtained even when applied to a vehicle including a passenger car having a large vehicle weight. .

DESCRIPTION OF SYMBOLS 1 Dodion-type suspension apparatus 2 Motor 4 Power transmission mechanism 6a, 6b Drive shaft 8a, 8b Wheel 10a, 10b Side rail (vehicle body)
12a, 12b Spindle (first hollow member)
14a, 14b saddle (second hollow member)
16a, 16b Leaf spring (elastic body)
18 Axle pipe (third hollow member)
46a Welding surface (joint surface)
48 continuous surfaces

Claims (1)

A dodion-type suspension system for a vehicle, comprising: a power transmission mechanism that transmits a driving force of a motor mounted on the vehicle; and a pair of drive shafts that respectively transmit the driving force transmitted to the power transmission mechanism to a pair of wheels. Because
A first hollow member that houses the drive shaft in the wheel;
A pair of second hollow members that are joined to the first hollow member, accommodate the drive shaft, and are connected to an elastic body that suspends the vehicle body of the vehicle;
An axle pipe that comprises a third hollow member and supports the pair of wheels by connecting the pair of second hollow members;
The dodion suspension for a vehicle, wherein an outer surface of the second hollow member continuous to a joint surface between the first hollow member and the second hollow member is formed as a continuous surface having no corners. apparatus.

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