Electric trucks

Abstract

An electric truck capable of reducing manufacturing costs. The electric truck (1) includes a drive unit (10) that is respectively arranged on the drive wheel (2A) of the electric truck (1) and transmits the driving force of the motor to the drive wheel (2A), a body frame (5), and a body connection part (32, 33). The body frame (5) includes a pair of assembly frame bodies (5A) extending in the vehicle width direction of the electric truck (1) and separated in the vehicle front and rear directions, and a pair of cross beams (5B, 5C) connecting the pair of assembly frame bodies (5A) to each other. The body connection part (32, 33) connects the vehicle front side and vehicle rear side of the drive unit (10) arranged in the frame of the body frame (5) to each assembly frame body (5A). In the frame of the body frame (5), the pair of drive units (10) are arranged adjacent to each other in the vehicle width direction.

Description

Technical Field

[0001] This case involves an electric truck that travels solely using the driving force of an electric motor. Background Art

[0002] In recent years, in order to reduce environmental impact, electric trucks, which are driven solely by electric motors without internal combustion engines, have been developed in the field of commercial vehicles such as trucks (see Patent Document 1). For example, a drive device used in such electric trucks, as shown in Patent Document 1, has been studied in which a drive motor and a speed reducer are integrally provided in a differential gear.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-026050 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Commercial vehicles, such as trucks, come in a variety of sizes, with varying gross vehicle weights and cargo types. Consequently, the optimal wheelbase between the front and rear wheels varies depending on the vehicle. Consequently, manufacturing an electric truck equipped with a drive system like the one described above increases the number of variations in the overall vehicle layout, complicating the overall vehicle packaging process during design, leading to concerns about increased manufacturing costs.

[0008] The present invention has been made in view of the above-mentioned problems, and one of its purposes is to provide an electric truck that can achieve a reduction in manufacturing cost.

[0009] Technical solutions to problems

[0010] The present invention is made to solve at least a part of the above-mentioned problems and can be implemented as the following technical solutions or application examples.

[0011] (1) The electric truck of this application example includes: a drive unit, which is respectively provided on the left and right drive wheels of the electric truck and transmits the driving force of the motor to the drive wheels; a vehicle frame frame, which includes a pair of assembly frame bodies extending in the vehicle width direction of the electric truck and separated in the vehicle front and rear directions, and a pair of cross beams connecting the pair of assembly frame bodies to each other; and a vehicle body connecting portion, which connects the vehicle front side and the vehicle rear side of the drive unit arranged in the frame of the vehicle frame frame to each of the assembly frame bodies, respectively, and in the frame of the vehicle frame frame, the pair of the drive units are arranged in a manner adjacent to each other in the vehicle width direction.

[0012] Thus, the vehicle's front and / or rear axle drive axles are formed by a vehicle frame body connecting a pair of drive units via a vehicle body connection. This allows electric trucks with varying gross vehicle weights, cargo types, and wheelbases to utilize a common drive system. In other words, there's no need to manufacture drive systems for each electric truck with varying specifications, reducing manufacturing costs. Furthermore, the ability to adjust the wheelbase improves product value for customers.

[0013] (2) In the electric truck of this application example, the drive unit may include: the motor; a reducer that reduces the rotation of the motor; a final gear that is connected to the reducer and transmits the driving force of the motor to the drive wheel; and a drive unit housing that integrally houses the motor, the reducer, and the final gear.

[0014] As described above, the drive unit includes the speed reducer, so a large driving force can be obtained. Furthermore, the motor and the like are integrally housed in the drive unit case, resulting in a compact structure.

[0015] (3) The electric truck of this application example may further include an air suspension portion provided above the final gear in the drive unit housing.

[0016] By providing the air suspension portion that absorbs vehicle body vibration on each drive wheel in this manner, it is possible to absorb vehicle body vibration while achieving a compact structure.

[0017] (4) The electric truck of this application example may also include a steering gear unit, which is provided on the driving wheel and is configured to be able to steer the driving wheel, and the steering wheel having the steering center of the driving wheel is arranged at an equal distance from each assembly frame of the pair of assembly frames.

[0018] With this configuration, the drive wheels are steered at the center in the front-rear direction within the vehicle body frame, thereby improving the layout balance.

[0019] (5) In the electric truck of this application example, the steering gear unit may be configured to steer the drive wheels to 90° in either direction when the steering angle of the drive wheels is set to 0° when the electric truck is moving straight ahead.

[0020] With this configuration, the steering performance is improved, and for example, parking in the left or right direction can also be performed.

[0021] (6) The electric truck of this application example may also include a pair of hinge parts, which are respectively arranged on the front side and rear side of the vehicle of the steering gear part, and a pair of vehicle body connecting parts respectively connect the steering gear part and the assembly frame body via the pair of hinge parts.

[0022] As described above, the steering gear portion is connected to the assembly frame body of the vehicle body frame body via the pair of hinge portions and the pair of vehicle body connection portions, so the driving feeling is improved.

[0023] (7) The electric truck of this application example may include dual tires formed by the two driving wheels, and the driving unit may transmit the driving force to the dual tires.

[0024] By adopting dual tires like this, it can also be applied to larger electric trucks.

[0025] Effects of the Invention

[0026] According to this embodiment, a common drive device can be applied to electric trucks of different specifications, thereby achieving a reduction in manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is an overall perspective view of an electric truck as one embodiment.

[0028] Figure 2 Is configured in Figure 1 A three-dimensional view of the front drive unit and its surroundings of an electric truck.

[0029] Figure 3 It is a side view of a drive device applied to an electric truck as one embodiment, and one wheel is omitted and shown.

[0030] Figure 4 yes Figure 3 Cross-sectional view as viewed from the AA arrow.

[0031] Figure 5 This is a perspective view of a drive device applied to an electric truck as one embodiment, in which dual tires are omitted.

[0032] Figure 6 It is a schematic cross-sectional view for explaining the main structure of the driving device.

[0033] Figure 7 This is a cross-sectional view of a drive device applied to an electric truck as one embodiment, taken along the vehicle front-rear direction through the steering center.

[0034] Figure 8 This is an example of applying a common drive system to electric trucks of different specifications. DETAILED DESCRIPTION

[0035] An electric truck as an embodiment will be described with reference to the accompanying drawings. The following embodiments are merely illustrative and are not intended to exclude variations or technical applications not explicitly described in the embodiments. The various components of the following embodiments can be implemented with various modifications without departing from their intended purpose. Furthermore, they can be selected or discarded as needed, or appropriately combined.

[0036] [1. Overall composition]

[0037] like Figure 1 As shown, the electric truck 1 of this embodiment does not have an internal combustion engine and uses only a motor 11 (see Figure 3 ) is used to drive a vehicle, and is provided with a driving device. Figure 1 , an electric truck 1 (hereinafter referred to as "truck 1") is shown as an example, including a pair of left and right side frames 1A (also referred to as chassis frames) extending in the vehicle's longitudinal direction, and a cab 1B disposed at the front of the vehicle. The vehicle body is omitted from the illustration. Furthermore, a frame extending in the vehicle width direction may be provided in addition to the side frames 1A, or the side frames 1A may be omitted.

[0038] In the following description, the forward direction of the truck 1 is referred to as the front, and the opposite direction is referred to as the rear. Left and right are defined with the truck 1 facing forward as the reference. The left and right directions are perpendicular to the vehicle's longitudinal direction. Hereinafter, the left and right directions are referred to as the "vehicle width direction," and the vehicle's longitudinal direction is simply referred to as the "front and rear direction."

[0039] like Figure 1 and Figure 2 As shown, the truck 1 of this embodiment is equipped with dual tires 2 consisting of two drive wheels 2A. In the truck 1 of this embodiment, a pair of left and right dual tires 2 are provided on the front side of the vehicle (front wheel side), and a pair of left and right dual tires 2 are provided side by side on the rear side of the vehicle (rear wheel side). However, the number of dual tires 2 in the front-to-back direction is not limited to this. Each dual tire 2 is provided with a drive unit 10 including a motor 11, which transmits the driving force of the motor 11 to the dual tires 2 (drive wheels 2A). The structure of the drive unit 10 will be described later.

[0040] The truck 1 includes: a vehicle body frame 5, including a pair of assembly frame bodies 5A extending in the vehicle width direction and a pair of cross beams 5B and a pair of cross beams 5C connecting them; and vehicle body connecting parts 32, 33, which connect the drive unit 10 arranged in the frame of the vehicle body frame 5 to each assembly frame body 5A.

[0041] A pair of assembly frame bodies 5A are arranged separately in the front-to-back direction. The cross beams 5B and 5C connect the front and rear assembly frame bodies 5A to each other. Within the frame of the vehicle body frame body 5, a pair of left and right drive units 10 are arranged adjacent to each other in the vehicle width direction. In the truck 1 of this embodiment, one vehicle body frame body 5 is provided on the front side of the vehicle (front wheel side), and two vehicle body frame bodies 5 are provided on the rear side of the vehicle (rear wheel side), but the number of front and rear vehicle body frame bodies 5 is not limited to this. In this way, in the truck 1 of this embodiment, the vehicle body frame body 5 to which the pair of left and right drive units 10 are connected by the vehicle body connecting parts 32 and 33 constitutes the front axle drive axle and rear axle drive axle of the vehicle.

[0042] In the vehicle frame 5 of this embodiment, the front and rear assembly frames 5A are composed of rectangular flat plate members extending in the vehicle width direction and in the vertical direction. In addition, the cross beam 5B located above the vehicle frame 5 is composed of a member with a U-shaped or hat-shaped cross-section extending in the front-to-back direction, connecting the flange portions of the upper ends of the front and rear assembly frames 5A to each other. On the other hand, the cross beam 5C located to the side of the vehicle frame 5 is composed of a flat plate member extending in the front-to-back direction and in the vertical direction, forming a recessed portion so as to surround the drive wheel 2A. In addition, either cross beam 5B or 5C can be omitted.

[0043] like Figure 2 As shown, the front vehicle body connection portion 32 connects the vehicle front side of the drive unit 10 in the frame to the front assembly frame body 5A, and the rear vehicle body connection portion 33 connects the vehicle rear side of the drive unit 10 in the frame to the rear assembly frame body 5A. Figure 3 and Figure 5 As shown, the front and rear vehicle body connecting parts 32 and 33 are formed similarly (symmetrically in the front and rear directions). Each vehicle body connecting part 32 and 33 extends in the front and rear directions and is connected to the assembly frame body 5A, forming a part of the frame of the truck 1.

[0044] A planar mounting surface 32a extending in a direction perpendicular to the front-to-back direction is provided at the front end portion of the front body connecting portion 32. Furthermore, a pair of connecting-side protrusions 32b protruding rearward are provided at the rear end portion of the front body connecting portion 32. The mounting surface 32a is a portion that is mounted on the assembly frame 5A and has a hole portion (not shown) for fastening the connection. Furthermore, the pair of connecting-side protrusions 32b are separated from each other in the vehicle width direction and have a hole portion 32c that passes through in the vehicle width direction. The connecting-side protrusions 32b constitute a portion of the hinge portion 40 described later and are connected to the steering gear portion 30 described later.

[0045] A planar mounting surface 33a extending perpendicularly to the front-to-rear direction is provided at the rear end of the rear vehicle body connection portion 33. Furthermore, a pair of connection-side protrusions 33b are provided at the front end of the rear vehicle body connection portion 33. These protrusions 33b protrude forward and have holes 33c. The configurations of the mounting surface 33a and the connection-side protrusions 33b are identical to those of the mounting surface 32a and the connection-side protrusions 32b described above.

[0046] like Figure 3 and Figure 4 As shown, the drive unit 10 includes a motor 11 that generates driving force; a speed reducer 12 that reduces the rotation of the motor 11; a final gear 14 that is connected to the speed reducer 12 and transmits the driving force of the motor 11 to a drive shaft 13 of the dual tire 2; and a drive unit case 15 that integrally houses these components. Specifically, the drive unit case 15 integrally houses the motor 11, speed reducer 12, and final gear 14.

[0047] The motor 11 is an electric generator that functions as an electric motor when the vehicle is driven and as a generator when the vehicle is decelerated. The reducer 12 reduces the rotation of the motor 11 and increases the motor torque (driving force). The drive shaft 13 is extended in the vehicle width direction when the truck 1 is moving straight ahead, and a pair of them are arranged on the left and right with the final gear 14 between them. The final gear 14 is located approximately in the center of the two drive wheels 2A in the vehicle width direction, and distributes the driving force of the motor 11 amplified by the reducer 12 to the two drive wheels 2A. In addition, the final gear 14 can also be included in the differential gear. However, in the case of dual tires 2, the distance between the two drive wheels 2A is closer than that of the usual left and right wheels, so the differential gear can be omitted.

[0048] The drive system of the truck 1 includes, in addition to the left and right drive units 10, a suspension portion 20 disposed above the final gear 14 within the drive unit housing 15, and a steering gear portion 30 disposed above the suspension portion 20. The drive system of this embodiment also includes a pair of hinge portions 40, one disposed on the vehicle front side and the other on the vehicle rear side of the steering gear portion 30, and the aforementioned vehicle body connecting portions 32 and 33.

[0049] The suspension part 20 is a part that functions as a suspension that absorbs the up and down vibrations of the dual tires 2. The steering gear part 30 is configured to be able to steer the dual tires 2, and has the function of steering the dual tires 2 around the steering shaft 30a (changing the steering angle). In addition, the steering of the dual tires 2 can be either manual or automatic. In addition, each dual tire 2 is driven and steered individually. The hinge part 40 has the function of suppressing the up and down vibrations of the dual tires 2 from being transmitted to the vehicle body. The vehicle body connecting parts 32 and 33 respectively connect the steering gear part 30 to the vehicle body of the truck 1 via a pair of hinge parts 40, and a pair is provided in the front and rear with the steering shaft 30a therebetween.

[0050] In this embodiment, if Figure 2 As shown, the suspension unit 20 and the steering gear unit 30 are both located above the two driving wheels 2A constituting the dual tire 2. Figure 3 In the illustrated drive device, the motor 11 is positioned forward of the vehicle relative to the final gear 14 and above the speed reducer 12. However, the position of the motor 11 can be determined based on the specifications and dimensions of the motor 11, the available space for the motor 11, and other factors. For example, the motor 11 can be positioned behind the final gear 14 or diagonally above it. Alternatively, the motor 11 output shaft (not shown) can be positioned so that it extends downward.

[0051] [2. Main components]

[0052] First, the suspension portion 20 will be described in detail. Figure 5 and Figure 6 As shown, the suspension unit 20 of this embodiment is an air suspension comprising an outer cylinder portion 21 centered around the steering shaft 30a of the dual tire 2, and an inner cylinder portion 22 arranged concentrically with the outer cylinder portion 21. The inner cylinder portion 22 is configured to slide axially along the inner circumference of the outer cylinder portion 21 and to be non-rotatable relative to the outer cylinder portion 21. The steering shaft 30a is an axial portion extending in the vertical direction, having a steering center Cs when the dual tire 2 is steered. The steering center Cs coincides with the centers of the outer cylinder portion 21 and the inner cylinder portion 22.

[0053] In addition, you can also Figure 7 As shown, the suspension part 20 also includes the coil spring 28 surrounding the outer tube part 21 and the inner tube part 22. The suspension part 20 including the coil spring 28 is suitable for a relatively light truck 1. On the other hand, Figure 5 and Figure 6 The suspension portion 20 shown without the coil spring 28 has a larger air capacity than the suspension portion 20 including the coil spring 28 and is suitable for a truck 1 having a larger weight. Figure 7 The suspension unit 20 shown is similar to the suspension unit 20 except that a coil spring 28 is provided. Figure 5 and Figure 6The suspension portion 20 shown is essentially the same. Therefore, in the following, Figure 7 It is also described as one of the embodiments.

[0054] like Figures 5 to 7 As shown, both the outer cylinder 21 and the inner cylinder 22 have a vertically elongated cylindrical shape, with the inner diameter of the outer cylinder 21 slightly larger than the outer diameter of the inner cylinder 22. The upper opening of the outer cylinder 21 is sealed by a cover 30b to which a steering shaft 30a is fixed. The lower opening of the outer cylinder 21 enters through the upper portion of the inner cylinder 22 and communicates with the inner cylinder 22. Furthermore, the upper opening of the inner cylinder 22 enters through the lower portion of the outer cylinder 21 and communicates with the outer cylinder 21. The lower opening of the inner cylinder 22 is sealed by a flat-plate-shaped drive head 25. Air is sealed inside the outer cylinder 21 and the inner cylinder 22.

[0055] The drive head 25 may also be Figure 6 As shown in the figure, the inner tube portion 22 is also fixed to the inner circumferential surface of the lower end portion of the inner tube portion 22 with a stepped shape. In this case, the fixation between the inner tube portion 22 and the drive head 25 becomes firm and can resist the lateral load. In addition, a stopper 24 is fixed to the lower end portion of the outer tube portion 21 to prevent the inner tube portion 22 from falling off and to seal it. In addition, when the suspension portion 20 is provided with a coil spring 28, as shown in the figure, the inner tube portion 22 is fixed to the drive head 25. Figure 7 As shown, coil springs 28 are arranged around the outer cylinder portion 21 and the inner cylinder portion 22 .

[0056] The outer cylinder portion 21 and the inner cylinder portion 22 are relatively displaced (slide) in the axial direction (vertical direction) in response to the vertical vibration of the truck 1 (vertical movement of the dual tires 2). Figure 6 As shown, the hanger portion 20 of this embodiment includes a low-friction member 23 disposed at the sliding contact position between the outer tube portion 21 and the inner tube portion 22. The low-friction member 23 is a member that reduces the sliding friction between the outer tube portion 21 and the inner tube portion 22, and is attached, for example, to the inner circumferential surface of the outer tube portion 21 and the outer circumferential surface of the inner tube portion 22. The low-friction member 23 prevents direct contact between the outer tube portion 21 and the inner tube portion 22, thereby reducing friction when the outer tube portion 21 and the inner tube portion 22 slide relative to each other in the vertical direction.

[0057] like Figure 5 and Figure 7 As shown, in this embodiment, an annular mounting portion 26 is fixed to the outer circumference of the upper portion of the outer tube portion 21. This mounting portion 26 is connected to the drive head 25 via a stabilizer 27 (also called a steering arm). This restricts relative rotation between the outer tube portion 21 and the inner tube portion 22. Furthermore, by connecting the upper portion of the outer tube portion 21 and the lower portion of the inner tube portion 22, relative vertical movement of the outer tube portion 21 and the inner tube portion 22 is permitted, thereby smoothing these movements.

[0058] In the suspension unit 20 of this embodiment, shock absorbers 29 are provided on both left and right sides of the stabilizer 27. The shock absorbers 29 have their upper ends connected to the mounting portion 26 and their lower ends connected to the drive head 25 via mounting members.

[0059] Next, the steering gear unit 30 will be described in detail. The steering gear unit 30 of this embodiment is configured to steer the dual tires 2 up to 90° in either the left or right direction, when the steering angle of the dual tires 2 is set to 0° (reference angle) when the truck 1 is traveling straight ahead (i.e., when the drive shaft 13 extends in the vehicle width direction). Specifically, the dual tires 2 can be steered 180° by the steering gear unit 30. When steered 90° to the left or right from the forward direction, the drive shaft 13 extends in the fore-aft direction, enabling the truck 1 to move in both the left and right directions.

[0060] like Figure 5 and Figure 7 As shown, the steering gear unit 30 includes a steering shaft 30a fixed to a cover 30b; a spur gear 30c fixed to the steering shaft 30a; an internal gear 30d meshing with the spur gear 30c; a cylindrical portion 30e concentrically disposed with the steering shaft 30a; and a drive unit 31 coupled to the internal gear 30d to rotate the internal gear 30d. The drive unit 31 is, for example, an actuator such as a hydraulic cylinder or a stepping motor.

[0061] exist Figure 5 In the example shown, when the driving unit 31 rotates the internal gear 30d clockwise, the spur gear 30c also rotates clockwise, and the steering shaft 30a also rotates clockwise, so the twin wheel 2 is steered to the right. Conversely, when the driving unit 31 rotates the internal gear 30d counterclockwise, the spur gear 30c also rotates counterclockwise, and the steering shaft 30a also rotates counterclockwise, so the twin wheel 2 is steered to the left. Figure 3 As shown, the steering shaft 30a is arranged at an equal distance from each of the pair of assembly frame bodies 5A.

[0062] like Figures 5 to 7 As shown, the cylindrical portion 30e is formed with a pair of front and rear protrusions 30f, which are connected to the connecting protrusions 32b and 33b of the vehicle body connecting portions 32 and 33, respectively. The protrusions 30f protrude forward and backward from the front and rear outer peripheral surfaces of the cylindrical portion 30e, respectively, and together with the connecting protrusions 32b and 33b, constitute the hinge portion 40. Specifically, the front protrusion 30f is interposed between the pair of connecting protrusions 32b, and a portion serving as the rotation center Ch of the hinge portion 40 is inserted into the hole 32c of each connecting protrusion 32b. In this embodiment, the cylindrical portion (not shown) of the protrusion 30f, which has a through-hole 30g extending therethrough in the vehicle width direction, is inserted into the hole 32c.

[0063] The rear protrusion 30f is similarly interposed between a pair of connecting protrusions 33b. A cylindrical portion, functioning as the rotation center Ch of the hinge 40, is inserted through the hole 33c of each connecting protrusion 33b. Furthermore, in this embodiment, a bushing (not shown) is interposed in the hinge 40 to absorb loads transmitted to the vehicle body. The interposition of the bushing absorbs loads transmitted to the vehicle body, further improving driving feel.

[0064] like Figure 6 and Figure 7 As shown, inside the cylindrical portion 30e, the cover 30b and the upper portion of the outer cylindrical portion 21 are concentrically arranged relative to the cylindrical portion 30e and supported for rotation. Specifically, the outer cylindrical portion 21, inner cylindrical portion 22, cover 30b, and drive head 25 rotate integrally with the cylindrical portion 30e, centered around the steering shaft 30a. A thrust plate 34 is interposed between the inner circumference of the cylindrical portion 30e and the outer circumference of the outer cylindrical portion 21 to withstand vertical loads. Furthermore, a stopper 36 is secured to the upper end of the thrust plate 34 to prevent the outer cylindrical portion 21 from falling off.

[0065] The thrust plate 34 of this embodiment includes a cylindrical portion 34a positioned between the cylindrical portion 30e and the outer cylindrical portion 21, and a flange portion 34b projecting radially outward from the lower end of the cylindrical portion 34a. The flange portion 34b is sandwiched between the upper surface of the mounting portion 26 and the lower surface of the cylindrical portion 30e. The thrust plate 34 is not fixed to any component and is a metal component that functions as a spacer, preventing direct contact between the fixed cylindrical portion 30e and the rotating outer cylindrical portion 21 and mounting portion 26. Furthermore, the thrust plate 34 is designed to be replaceable due to wear.

[0066] The steering gear unit 30 of this embodiment includes a low-friction member 35 disposed at the sliding contact position between the outer cylinder 21 and the thrust plate 34. The low-friction member 35 is a member that reduces friction between the outer cylinder 21 and the thrust plate 34 and is attached, for example, to the outer circumferential surface of the outer cylinder 21 or the inner circumferential surface of the thrust plate 34. The low-friction member 35 reduces friction during relative displacement between the outer cylinder 21 and the thrust plate 34.

[0067] [3. Function and Effect]

[0068] According to the above-described truck 1, the following operations and effects can be obtained.

[0069] (1) The drive unit is packaged by arranging a pair of drive units 10 adjacent to each other in the frame of the vehicle body frame 5 and connecting them by the vehicle body connecting parts 32 and 33. Therefore, for example, Figure 8As shown, even electric trucks 1' and 1" with different gross vehicle weights, types of cargo, wheelbases, etc. can use a common drive device. In other words, there is no need to manufacture a drive device for each electric truck with different specifications, so the manufacturing cost can be reduced. In addition, the wheelbase can be adjusted for the customer, which can improve the product value. In addition, Figure 8 The electric truck 1′ is a truck with one axle on the front wheel side and one axle on the rear wheel side. Figure 8 The electric truck 1 ″ is a truck having one axle on the front wheel side and two axles on the rear wheel side. By using the above-mentioned drive device, an appropriate number of axles can be configured on the front wheel side and the rear wheel side.

[0070] (2) In the above-described truck 1, the drive unit 10, which includes the drive unit housing 15 that integrally houses the motor 11, the speed reducer 12, and the final gear 14, is provided for each of the left and right drive wheels 2A of the truck 1. Thus, the drive unit 10 includes the speed reducer 12, so that a large driving force can be obtained. Furthermore, the motor 11 and other components are integrally housed in the drive unit housing 15, so that a compact structure can be achieved.

[0071] (3) According to the above-described truck 1 , the air suspension portion 20 is provided above the final gear 14 in the drive unit case 15 , so that vehicle body vibration can be absorbed with a compact structure.

[0072] (4) In the above-described truck 1, the steering shaft 30a is arranged at an equal distance from each of the pair of assembly frames 5A. In other words, the dual tires 2 are steered at the front-rear center of the vehicle frame 5, thereby improving the arrangement balance.

[0073] (5) According to the above-mentioned truck 1, the steering gear unit 30 is configured to be able to steer the drive wheel 2A to 90° (i.e., 180°) in either direction from the reference, thereby improving the steering performance and enabling, for example, parking in the left and right directions.

[0074] (6) In the above-described truck 1, the steering gear unit 30 is connected to the assembly frame 5A via a pair of hinges 40 via a pair of vehicle body connecting portions 32 and 33. The hinges 40 have the function of suppressing the vertical vibration of the drive wheels 2A from being transmitted to the vehicle body. Therefore, in addition to the suspension unit 20, the hinges 40 can also suppress vehicle body vibration, thereby improving the driving feel.

[0075] (7) Furthermore, as described above, if the truck 1 includes the dual tires 2 and the drive unit 10 transmits the driving force to the dual tires 2 , the drive device can also be applied to larger electric trucks.

[0076] (8) In addition, in the drive device of this embodiment, the drive unit 10, which includes a drive unit housing 15 that integrally houses the motor 11, the speed reducer 12, and the final gear 14, is provided for each of the dual tires 2 on the left and right sides of the truck 1, and the suspension unit 20 and the steering gear unit 30 are provided above the final gear 14. According to such a drive device, the dual tires 2 are driven and steered independently, so that a steering angle of, for example, 0° to 180° can be achieved, which can reduce the turning radius. Therefore, it is possible to provide a drive device for the truck 1 that has steering performance of a steering angle of 0° to 180° while adopting a dual tire structure.

[0077] (9) In particular, in the drive device of this embodiment, the suspension unit 20 and the steering gear unit 20 are both located above the two drive wheels 2A constituting the dual tire 2, so the weight balance is good, which can improve the steering performance of the dual tire 2.

[0078] (10) In the drive device of this embodiment, the suspension unit 20 is an air suspension, which includes an outer cylinder 21 centered on the steering shaft 30a of the dual tire 2, and an inner cylinder 22 that is axially slidable along the inner circumference of the outer cylinder 21 and is non-rotatable relative to the outer cylinder 21. Therefore, the structure can be simplified compared to hydraulic suspensions and electromagnetic suspensions.

[0079] (11) Figure 7 As shown, by configuring the suspension portion 20 to also include the coil spring 28 , it is possible to configure the suspension portion 20 that is appropriate for the total weight of the vehicle.

[0080] (12) In addition, the suspension portion 20 of this embodiment includes a low-friction member 23 arranged at the sliding contact position between the outer tube portion 21 and the inner tube portion 22, so that the friction when the outer tube portion 21 and the inner tube portion 22 slide relative to each other can be reduced, and the performance of the air suspension can be improved.

[0081] (13) According to the above-mentioned driving device, the upper part of the outer cylinder part 21 and the lower part of the inner cylinder part 22 are connected to each other by a connecting rod, so the relative rotation of the outer cylinder part 21 and the inner cylinder part 22 is restricted. On this basis, relative up and down movement can be allowed, and the axial movement of the outer cylinder part 21 and the inner cylinder part 22 can be smooth.

[0082] (14) In the drive device of this embodiment, the thrust plate 34 interposed between the cylindrical portion 30e and the outer cylindrical portion 21 functions as a spacer, thereby preventing direct contact between the cylindrical portion 30e on the fixed side and the outer cylindrical portion 21 and the mounting portion 26 on the rotating side. Furthermore, the thrust plate 34 bears loads in the vertical direction, thereby further improving the driving feel.

[0083] (15) In particular, the steering gear unit 30 of this embodiment includes the low-friction member 35 disposed at the sliding contact position between the outer cylinder portion 21 and the thrust plate 34. This reduces friction during relative displacement between the outer cylinder portion 21 and the thrust plate 34. Consequently, steering performance can be further improved.

[0084] [4. Modifications]

[0085] The aforementioned drive device and truck 1 are examples. For example, the aforementioned suspension unit 20 may be an air suspension comprising an outer cylinder 21 and an inner cylinder 22, or a combination of an air suspension and coil springs 28. However, the suspension unit can be selected based on the load and application, and a hydraulic suspension or an electromagnetic suspension may also be employed.

[0086] The low-friction members 23, 35 and thrust plate 34 described above are not essential and can be omitted. Furthermore, the structure for limiting relative rotation between the outer cylinder 21 and the inner cylinder 22 is not limited to the link connection using the stabilizer 27. Furthermore, the steering gear unit 30 can also be implemented using gears other than the spur gear 30c and the internal gear 30d. The steering angle range of the dual tire 2 can be set according to the required turning radius.

[0087] In the above-mentioned truck 1, the drive device is packaged by arranging a pair of drive units 10 adjacent to each other in the vehicle width direction within the frame of the vehicle body frame 5, but a drive unit other than the above-mentioned drive unit 10 may be arranged within the vehicle body frame 5. For example, the reducer 12 may not be included in the drive unit housing 15, and the configuration of the suspension part 20 and the steering gear part 30 may also be different from the above-mentioned. In addition, the hinge part 40 is not required and may be omitted. In addition, the above-mentioned truck 1 is equipped with dual tires 2, but may also be a single tire. In this case, the drive unit can be arranged on each drive wheel in consideration of weight balance.

[0088] Description of Reference Numerals

[0089] 1, 1′, 1″ trucks (electric trucks)

[0090] 2 dual tires

[0091] 2A drive wheel

[0092] 5 Body frame

[0093] 5A assembly frame

[0094] 5B, 5C cross beams

[0095] 10 drive units

[0096] 11 Motor

[0097] 12 Reducer

[0098] 14 Final Gear

[0099] 15 Drive unit housing

[0100] 20 Suspension

[0101] 21 Outer cylinder

[0102] 22 Inner cylinder

[0103] 30 Steering gear unit

[0104] 30a Steering shaft

[0105] 32 Front body connection

[0106] 33 Rear body connection

[0107] Cs Steering Center

Claims

1. An electric truck comprising: A drive unit is provided on the left and right drive wheels of the electric truck, and transmits the driving force of the motor to the drive wheels; a vehicle body frame including a pair of assembly frame bodies extending in the vehicle width direction of the electric truck and spaced apart in the vehicle front-rear direction, and a pair of cross beams connecting the pair of assembly frame bodies; and The vehicle body connecting portion connects the vehicle front side and the vehicle rear side of the drive unit disposed in the frame of the vehicle body frame to the respective assembly frame bodies. A pair of the drive units are arranged adjacent to each other in the vehicle width direction within the vehicle frame. The drive unit includes: the motor; a speed reducer that reduces the speed of the motor; a final gear that is connected to the speed reducer and transmits the driving force of the motor to the drive wheel; and a drive unit housing that integrally houses the motor, the speed reducer, and the final gear. The electric truck further includes an air suspension portion provided above the final gear within the drive unit housing.

2. The electric truck according to claim 1, It also includes a steering gear unit, which is provided on the driving wheel and configured to steer the driving wheel. A steering shaft having a steering center of the drive wheel is arranged at an equal distance from each of the pair of assembly frame bodies.

3. The electric truck according to claim 2, The steering gear unit is configured to steer the drive wheels to 90 degrees in either direction, when the steering angle of the drive wheels is set to 0 degrees in a state where the electric truck is moving straight ahead.

4. The electric truck according to claim 2, The steering gear unit further includes a pair of hinge portions, the pair of hinge portions being respectively provided on the vehicle front side and the vehicle rear side of the steering gear unit. The pair of vehicle body connection portions connects the steering gear portion and the assembly frame body via the pair of hinge portions, respectively.

5. The electric truck according to any one of claims 1 to 4, The electric truck is provided with dual tires consisting of two driving wheels. The drive unit transmits the driving force to the dual tires.

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