Battery mounting structure for vehicle drive motor

Abstract

To provide a vehicle drive motor battery mounting structure that can prevent a vehicle body frame from being deformed by the self-weight of a heavy battery for a vehicle drive motor with a simple structure and at low cost in a structure where the heavy battery is mounted on the vehicle body frame.SOLUTION: In a structure where a battery 5 for a vehicle drive motor 4 is mounted on a vehicle body frame 2, the vehicle body frame 2 includes a pair of side members 3 extending in a vehicle longitudinal direction at an interval in a vehicle width direction. Battery mounting brackets 7 for mounting a battery by which the battery 5 for the vehicle drive motor 4 are mounted on the side members 3, are attached respectively to the side members 3 to protrude downward therefrom. A reinforcement cross member 14 extending along the vehicle width direction is bridged between portions 7c protruded downward from the side members 3 of the brackets 7 for mounting the battery.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a structure in which a battery for a vehicle drive motor is mounted on a vehicle body frame of an electrically driven truck, bus, etc. In particular, the present invention relates to a battery mounting structure for a vehicle drive motor that suppresses deformation of the vehicle body frame due to the weight of the battery for the vehicle drive motor (which is as heavy as several hundred kilograms).

Background Art

[0002] In recent years, the power sources of automobiles have been trending towards zero emissions, and electrification is also being promoted in trucks, buses, etc. Here, since trucks, buses, etc. have a heavy total vehicle weight (vehicle weight + payload weight), in order to ensure the driving distance required for business, it is necessary to mount a plurality of large-capacity and heavy batteries. These batteries for vehicle drive motors (several hundred kilograms) are, for example, assembled to the left and right of the vehicle body frame via brackets. However, since they are much heavier than ordinary batteries (several tens of kilograms) used as power sources for conventional diesel engine vehicles, etc., if they are assembled to the vehicle body frame in the same way as conventional ordinary batteries, the vehicle body frame will have insufficient strength and may deform due to long-term use. This point will be explained below.

[0003] Fig. 1 shows the outline of an electric drive truck (EV truck) 1j previously conceived by the inventor of the present invention. Fig. 1(a) is a side view of the EV truck 1j, Fig. 1(b) is a plan view of the vehicle body frame 2 of the EV truck 1j, and Fig. 1(c) is a cross-sectional view of the side member 3 of the vehicle body frame 2 of the EV truck 1j. As shown in Fig. 1(b), the vehicle body frame 2 is equipped with a vehicle drive motor 4 for driving the EV truck 1j and batteries 5 and 5a for supplying power to the vehicle drive motor 4. The vehicle body frame 2 includes a pair of side members 3 extending in the vehicle length direction at intervals in the vehicle width direction and a plurality of cross members 6 spanned between these side members 3 at intervals in the vehicle length direction, forming a so-called ladder frame. As shown in Fig. 1(c), the side member 3 includes a web 3a composed of a vertical wall along the vehicle length direction, an upper flange 3b extending inward in the vehicle width direction from the upper end of the web 3a, and a lower flange 3c extending inward in the vehicle width direction from the lower end of the web 3a, and is formed in a U-shaped cross section.

[0004] The cross-sectional view taken along line IIa-IIa in Fig. 1(b) is shown in Fig. 2(a), the cross-sectional view taken along line IIb-IIb in Fig. 1(b) is shown in Fig. 2(b), and the cross-sectional view taken along line IIc-IIc in Fig. 1(c) is shown in Fig. 2(c). As shown in Fig. 2(a), a battery mounting bracket 7 for mounting the battery 5 for the vehicle drive motor 4 is attached to the outer side portion in the vehicle width direction of the web 3a of the pair of side members 3 constituting the vehicle body frame 2 by bolts, nuts 8, etc. The battery mounting bracket 7 is formed in an L-shaped cross section from a vertical portion 7a attached to the outer side portion in the vehicle width direction of the web 3a so as to protrude below the lower flange 3c and a horizontal portion 7b extending outward in the vehicle width direction from the lower end of the vertical portion 7a, and the battery 5 for the vehicle drive motor 4 is mounted on the horizontal portion 7b. Thereby, the heavy battery 5 for the vehicle drive motor 4 can be arranged as low as possible with respect to the side member 3, improving the stability during vehicle running.

[0005] As shown in FIG. 1(b), the vehicle drive motor 4 is arranged between the batteries 5 on the left and right in the vehicle width direction, and as shown in FIG. 2(b), it is supported by a pair of side members 3 via a motor support bracket 9 having a U-shaped cross section. A U-shaped cross-section member 10 that is slightly smaller in size is welded in the middle so as to face the side member 3 at the portion that supports the vehicle drive motor 4, and the motor support bracket 9 is attached to the U-shaped cross-section member 10. Further, as shown in FIG. 1(b), another battery 5a (center battery) for the vehicle drive motor 4 is arranged in front of the vehicle drive motor 4. As shown in FIG. 2(c), the center battery 5a is supported by a pair of side members 3 via a battery support bracket 11 having a U-shaped cross section. A U-shaped cross-section member 12 that is slightly smaller in size is welded in the middle so as to face the side member 3 at the portion where the battery support bracket 11 is attached, and the battery support bracket 11 is attached to the U-shaped cross-section member 12.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Incidentally, as shown in Fig. 2(a), the weight (several hundred kilograms) of the battery 5 for the vehicle drive motor supported via the battery mounting bracket 7 having an L-shaped cross section on the web 3a of the side member 3 is much heavier than the weight (several tens of kilograms) of a normal battery used as a power source for a diesel engine vehicle or the like, as described above. For this reason, due to the moment M (M = W × L) obtained by multiplying the battery weight W acting vertically downward on the center-of-gravity position of the battery 5 by the horizontal distance L from the center-of-gravity position to the attachment portion of the battery mounting bracket 7 to the web 3a of the side member 3, as shown in Fig. 3, the web 3a of the side member 3 collapses inward in the vehicle width direction, and the side member 3 is deformed. If driving is continued for a long period in this state, it is conceivable that the side member 3 may undergo fatigue failure.

[0008] As a countermeasure for suppressing the deformation of the side member 3, as shown in Fig. 4(a), it is conceivable to add a reinforcing member 13 (for example, a U-shaped cross-section member) to a part (cross-hatch display portion 3x) of the side member 3 where the weight of the battery 5 for the vehicle drive motor 4 acts, as shown in Fig. 4(b). Also conceivable are increasing the plate thickness of the side member 3 or changing the material of the side member 3 to a high-strength material (such as high-tensile steel). However, in any of these countermeasures, an increase in weight and cost cannot be avoided.

[0009] Patent Document 1 discloses a normal battery used as a power source for a diesel engine vehicle or the like mounted via a bracket having an L-shaped cross section on the outer portion in the vehicle width direction of a side member constituting a vehicle body frame. However, since this battery is not for the vehicle drive motor of a so-called EV truck and is light in weight (several tens of kilograms), as shown in Fig. 3, there is no problem of the side member 3 being deformed due to the moment M generated by the self-weight W of the heavy (several hundred kilograms) battery 5 for the vehicle drive motor 4.

[0010] The object of the present invention, which has been devised in consideration of the above circumstances, is to provide a battery mounting structure for a vehicle drive motor, in a structure where a heavy battery for a vehicle drive motor is mounted on a vehicle body frame, to suppress deformation of the vehicle body frame due to the dead weight of the heavy battery with a simple structure and at low cost.

Means for Solving the Problems

[0011] According to the present invention devised to achieve the above object, there is provided a structure for mounting a battery for a vehicle drive motor on a vehicle body frame, wherein the vehicle body frame has a pair of side members extending in the vehicle length direction with a space therebetween in the vehicle width direction, and battery mounting brackets for mounting the battery are respectively attached to these side members so as to protrude downward from the side members, and a reinforcing cross member along the vehicle width direction is bridged over the portions of these battery mounting brackets protruding downward from the side members. A battery support cross member for mounting another battery for a vehicle drive motor is spanned below a pair of side members in front of the reinforcing cross member. A battery mounting structure for a vehicle drive motor is provided, which is characterized by the above.

[0012] In the battery mounting structure for a vehicle drive motor according to the present invention, the side member has a web formed of a vertical wall along the vehicle length direction, an upper flange extending inward in the vehicle width direction from the upper end of the web, and a lower flange extending inward in the vehicle width direction from the lower end of the web. The battery mounting bracket has a vertical portion attached to the web so as to protrude downward more than the lower flange, and a horizontal portion extending outward in the vehicle width direction from the lower end of the vertical portion on which the battery is placed. Both ends of the reinforcing cross member are fixed to the portions protruding downward from the lower flange of the vertical portion and are also fixed to the lower flange. Both ends of the battery support cross member are fixed to lower flanges of the pair of side members. It may be.

[0013] In the battery mounting structure for a vehicle drive motor according to the present invention, The battery support cross member has the same shape as the reinforcing cross member. It may also be.

Effects of the Invention

[0014] According to the battery mounting structure for a vehicle drive motor according to the present invention, the following effects can be exhibited. (1) A reinforcing cross member extending along the vehicle width direction is bridged over a portion protruding downward from a side member of a battery mounting bracket attached to the left and right side members in the vehicle width direction. Therefore, when the left and right battery mounting brackets in the vehicle width direction tend to rotate inwardly and the side member tends to deform due to a moment generated by the self-weight of the battery (for vehicle drive motor and extremely heavy) mounted on the battery mounting bracket, the reinforcing cross member receives a compressive force and functions as a so-called tension member, suppressing the inward rotation of the battery mounting bracket and the deformation of the side member. (2) Since the reinforcing cross member functions as a tension member in this way and can suppress the inward rotation of the battery mounting bracket and the deformation of the side member, it is not necessary to increase the strength of the side member itself. Therefore, measures such as increasing the plate thickness of the side member, changing the material of the side member to a high-strength material (such as high-tensile steel), and adding a reinforcing member to the side member are not necessary, and the cost of the side member does not increase. That is, it is possible to suppress, at low cost with a simple configuration, the deformation of the vehicle body frame caused by a heavy battery for a vehicle drive motor.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0016] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values shown in such embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to omit redundant description, and elements not directly related to the present invention are not shown.

[0017] (Outline of Battery Mounting Structure for Vehicle Drive Motor) Fig. 5(a) shows a side view of an electric drive truck 1 (EV truck) according to an embodiment of the present invention, Fig. 5(b) shows a plan view of the vehicle body frame 2 of the EV truck 1, and Fig. 5(c) shows a cross-sectional view of the side member 3 of the vehicle body frame 2 of the EV truck 1. As shown in Fig. 5(b), the vehicle body frame 2 is equipped with a vehicle drive motor 4 for driving the EV truck 1 and batteries 5 and 5a for supplying power to the vehicle drive motor 4.

[0018] As shown in Fig. 5(b), the vehicle body frame 2 includes a pair of side members 3 extending in the vehicle length direction with a space therebetween in the vehicle width direction, and a plurality of cross members 6 spanned between these side members 3 with a space therebetween in the vehicle length direction, forming a so-called ladder frame. As shown in Fig. 5(c), the side member 3 includes a web 3a formed of a vertical wall along the vehicle length direction, an upper flange 3b extending inward in the vehicle width direction from the upper end of the web 3a, and a lower flange 3c extending inward in the vehicle width direction from the lower end of the web 3a, and is formed in a U-shaped cross section.

[0019] As shown in Fig. 6(a) which is a sectional view taken along line VIa-VIa of Fig. 5(b), battery mounting brackets 7 for mounting the batteries 5 for the vehicle drive motor 4 are respectively attached to the left and right side members 3 in the vehicle width direction by bolts and nuts 8, rivets, welding, etc. so as to protrude downward from the side members 3. A reinforcing cross member 14 along the vehicle width direction is attached to the portion 7c protruding downward from the side members 3 of these battery mounting brackets 7 so as to be spanned by bolts and nuts 8, rivets, welding, etc.

[0020] The weights (several hundred kilograms) of the batteries 5, 5a for the vehicle drive motor 4 of the EV truck 1 shown in Fig. 5(a) are much heavier than the weights (several tens of kilograms) of the batteries used for the power supply of ordinary diesel engine vehicles. For example, one battery 5, 5a is about 200 kg. As shown in Fig. 5(b), since such heavy batteries 5 are arranged symmetrically in a pair on the left and right in the vehicle width direction and the battery 5a is arranged at the center in the vehicle width direction, the balance during vehicle running is good.

[0021] (Battery mounting bracket 7) As shown in Fig. 6(a), the battery mounting bracket 7 is formed in an L-shaped cross-section from a vertical portion 7a attached to the outer side portion in the vehicle width direction of the web 6a of the side member 3 so as to protrude downward from the lower flange 3c, and a horizontal portion 7b extending outward in the vehicle width direction from the lower end of the vertical portion 7a. A battery 5 (several hundred kilograms) for the vehicle drive motor 4 is mounted on the horizontal portion 7b. Thereby, the heavy battery 5 for the vehicle drive motor 4 can be arranged as low as possible with respect to the side member 3, and the stability during vehicle travel is improved. For example, by extending the vertical portion 7a downward and lowering the height of the horizontal portion 7b to near the legal minimum ground clearance, it is also possible to position the center of gravity of the battery 5 below the lower flange 3c of the side member 3.

[0022] (Reinforcing cross member 14) As shown in Fig. 6(a), a reinforcing cross member 14 extending in the vehicle width direction is spanned across a portion 7c protruding downward from the lower flange 3c of the vertical portion 7a of the battery mounting brackets 7 on the left and right in the vehicle width direction. The reinforcing cross member 14 includes a horizontal beam 14a extending in the vehicle width direction, vertical plates 14b extending upward from both ends of the horizontal beam 14a, and a horizontal plate 14c extending inward in the vehicle width direction from the upper ends of the vertical plates 14b. The vertical plates 14b are attached to the portion 7c below the lower flange 3c of the side member 3 of the vertical portion 7a of the battery mounting bracket 7 by bolts, nuts 8, rivets, welding, etc., and the horizontal plate 14c is similarly attached to the lower flange 3c of the side member 3 by bolts, nuts 8, etc. That is, both ends of the reinforcing cross member 14 are fixed to the portion 7c protruding downward from the lower flange 3c of the vertical portion 7a of the battery mounting bracket 7 and are also fixed to the lower flange 3c of the side member 3 of the vehicle body frame 2. The vehicle drive motor 4 is placed on the horizontal beam 14a of this reinforcing cross member 14.

[0023] (Center battery 5a) As shown in Fig. 5(b), another battery 5a (center battery) for the vehicle drive motor 4 is arranged in front of the vehicle drive motor 4. As shown in Fig. 6(b), the center battery 5a is supported by a pair of side members 3 via a battery support cross member 15 having the same shape as the reinforcing cross member 14. Similar to the reinforcing cross member 14, the battery support cross member 15 has a horizontal beam 15a, a vertical plate 15b, and a horizontal plate 15c, and the horizontal plate 15c is attached to the lower flange 3c of the side member 3 by bolts and nuts 8, rivets, welding, etc.

[0024] (Function and Effect) As shown in Fig. 6(a), according to the battery mounting structure for the vehicle drive motor 4 according to this embodiment, a reinforcing cross member 14 along the vehicle width direction is spanned over a portion 7c protruding downward from the side member 3 of the battery mounting brackets 7 respectively attached to the left and right side members 3 in the vehicle width direction. As a result, when the left and right battery mounting brackets 7 in the vehicle width direction tend to rotate inward and the side member 3 tends to deform due to the moment M generated by the dead weight (several hundred kilograms) of the battery 5 (for the vehicle drive motor 4 and extremely heavy) mounted on the battery mounting bracket 7 (see Fig. 3), the reinforcing cross member 14 shown in Fig. 6(a) receives a compressive force and functions as a so-called bracing member, suppressing the inward rotation of the battery mounting bracket 7 and the deformation of the side member 3.

[0025] In this way, the reinforcing cross member 14 shown in Fig. 6(a) functions as a strut member, which can suppress the inward rotation of the battery mounting bracket 7 and the deformation of the side member 3. Therefore, it is not necessary to increase the strength of the side member 3 itself. Thus, measures such as increasing the plate thickness of the side member 3, changing the material of the side member 3 to a high-strength material (such as high-tensile steel), and adding a reinforcing member 13 to the side member 3 (see Figs. 4(a) and 4(b)) are not required, and the cost of the side member 3 does not increase. That is, the deformation of the vehicle body frame 3 caused by the heavy battery 5 (several hundred kilograms) for the vehicle drive motor 4 can be accurately suppressed at low cost with a simple configuration of adding a minimum strut member (reinforcing cross member 14) to the necessary parts.

[0026] As shown in Fig. 6(a), the battery mounting bracket 7 is formed in an L-shaped cross section from a vertical portion 7a protruding downward from the lower flange 3c of the side member 3 and a horizontal portion 7b extending outward in the vehicle width direction from the lower end of the vertical portion 7a. Since the battery 5 is mounted on the horizontal portion 7b, the heavy battery 5 can be arranged as low as possible, improving the stability during vehicle running. As a result of arranging the battery 5 as low as possible by using such an L-shaped cross-section battery mounting bracket 7, when the battery mounting bracket 7 rotates inward and the side member 3 tends to deform due to the moment M generated by the self-weight W of the battery 5 as shown in Figs. 2(a) and 3, in this embodiment, the reinforcing cross member 14 shown in Fig. 6(a) functions as a strut member, suppressing the inward rotation of the battery mounting bracket 7 and the deformation of the side member 3.

[0027] As shown in Fig. 6(a), the vertical plates 14b at both ends of the reinforcing cross member 14 are fixed to the portion 7c protruding downward from the lower flange 3c of the vertical portion 7a of the battery mounting bracket 7 with bolts, nuts 8, etc. The horizontal plates 14c at both ends of the reinforcing cross member 14 are similarly fixed to the lower flange of the side member 3. With this configuration, the reinforcing cross member 14 functions as a reinforcing member that, in conjunction with the battery mounting bracket 7, enhances the rigidity of the portion of the side member 3 where the weight W of the battery 5 is applied, and can suppress the deformation of the side member 3 due to the weight W of the battery 5.

[0028] As shown in Fig. 6(a), the vehicle drive motor 4 is mounted on the horizontal beam 14a of the reinforcing cross member 14. Therefore, in addition to functioning as a tension member and a reinforcing member as described above, the reinforcing cross member 14 also functions as a mounting member for mounting the vehicle drive motor 4. Since this reinforcing cross member 14 is fixed to the portion 7c protruding downward from the lower flange 3c of the vertical portion 7a of the battery mounting bracket 7, the vehicle drive motor 4 mounted on the reinforcing cross member 14 will be arranged at the same height as the battery 5. Thus, the heavy vehicle drive motor 4 can be arranged at a position as low as possible and equivalent to that of the battery 5, improving the stability during vehicle running. In this embodiment, the horizontal beam 14a of the reinforcing cross member 14 and the horizontal portion 7b of the battery mounting bracket 7 are at the same height.

[0029] As shown in Fig. 6(b), since the battery support cross member 15 that supports the center battery 5a has the same shape as the reinforcing cross member 14 shown in Fig. 6(a), component commonality is possible, reducing costs. Also, the center battery 5a can be arranged at a position as low as possible and equivalent to that of the vehicle drive motor 4 and the battery 5, improving the stability during vehicle running.

[0030] While the preferred embodiments of the present invention have been described with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications or variations within the scope described in the claims also belong to the technical scope of the present invention.

[0031] In this specification, the concept of electric drive means at least driving a vehicle electrically, and includes not only pure electric drive but also hybrids of electric drive + engine drive.

Industrial Applicability

[0032] The present invention can be used for a battery mounting structure for a vehicle drive motor in a vehicle body frame such as an electrically driven truck or bus, which suppresses deformation of the vehicle body frame due to the weight (several hundred kilograms) of the battery for the vehicle drive motor.

Explanation of Reference Numerals

[0033] 1 Electric drive truck (EV truck) 2 Vehicle body frame 3 Side member 3a Web 3b Upper flange 3c Lower flange 4 Vehicle drive motor 5 Battery for vehicle drive motor 5a Another battery (center battery) 7 Battery mounting bracket 7a Vertical part 7b Horizontal part 7c Portion protruding downward from the lower flange of the vertical part 14 Reinforcing cross member 14a Horizontal beam 14b Vertical plate 14c Horizontal plate 15 Battery support cross member

Claims

1. A structure in which a battery for a vehicle drive motor is mounted on a vehicle body frame, wherein the vehicle body frame has a pair of side members extending in the vehicle length direction with a space therebetween in the vehicle width direction, and battery mounting brackets for mounting the battery are respectively attached to these side members so as to project downward from the side members, and a reinforcing cross member extending along the vehicle width direction is bridged over a portion of these battery mounting brackets projecting downward from the side members, and a battery support cross member for mounting another battery for the vehicle drive motor is bridged over lower portions of the pair of side members in front of the reinforcing cross member. A battery mounting structure for a vehicle drive motor, characterized by this.

2. The side member has a web formed of a vertical wall extending along the vehicle length direction, an upper flange extending inward in the vehicle width direction from an upper end of the web, and a lower flange extending inward in the vehicle width direction from a lower end of the web, the battery mounting bracket has a vertical portion attached to the web so as to project downward from the lower flange, and a horizontal portion extending outward in the vehicle width direction from a lower end of the vertical portion on which the battery is placed, both ends of the reinforcing cross member are fixed to a portion of the vertical portion projecting downward from the lower flange and are also fixed to the lower flange, and both ends of the battery support cross member are fixed to the lower flanges of the pair of side members. A battery mounting structure for a vehicle drive motor according to claim 1, characterized by this.

3. The battery support cross member has the same shape as the reinforcing cross member. A battery mounting structure for a vehicle drive motor according to claim 1 or 2, characterized by this.

Images