Postural change suppressing mechanism

Abstract

To provide a postural change suppressing mechanism that prevents oscillation of a rear gate, even when rattling occurs in a shaft part of the rear gate.SOLUTION: A coupling member 33 is fixed to a vehicle rear side end of a push rod 31. The coupling member 33 is swingably connected about a shaft along a vehicle width direction using a coupling shaft 5, to a coupling part 2a of a rear gate 2. In a screw hole 36 formed in the coupling member 33, an oscillation regulating member 37 with a male screw formed on its outer periphery is screwed. In the oscillation regulating member 37, a portion thereof projects from an upper part of the coupling member 33. The projection amount can be adjusted by rotating the oscillation regulating member about its axis. When a load carrying platform 102 is in the storage posture, and the rear gate 2 is in a closed posture, a tip of the oscillation regulating member 37 is in a state of abutting on an opening / closing shaft bracket 2c of the coupling part 2a.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a rear tailgate position change suppression mechanism provided on a freight vehicle that can change the position of the cargo bed between a stored position in which the bed is placed on a chassis frame and a ground contact position in which the bed is placed on the ground. [Background technology]

[0002] The position of the cargo bed can be changed between a stored position in which the bed is placed on the chassis frame and a grounded position in which the bed is placed on the ground, and a freight vehicle equipped with a rear gate at the rear of the cargo bed has a configuration such as that disclosed in Patent Document 1.

[0003] Such a freight truck comprises a guide frame that is fixed to the chassis frame of the vehicle body and is positioned between the chassis frame and the loading platform, and is displaceable relative to the loading platform; and a tilting frame that is positioned between the guide frame and the loading platform and is displaceable relative to the guide frame and the loading platform, and the position of the loading platform is changed by extending and retracting hydraulic cylinders provided on the guide frame and the tilting frame. The rear gate is supported at the rear of the loading platform so that it can rotate around an axis that runs along the vehicle width direction. Therefore, a mechanism for suppressing the rear gate's position change is provided so that it can maintain a closed position while the loading platform is in a stored position. The position of the rear gate is often changed manually, and this can be achieved by releasing a hook provided on the mechanism when the loading platform is in a grounded position.

[0004] The freight vehicle disclosed in Patent Document 1 is equipped with a pressure force transmission member and a push rod under the bed as a posture change suppression mechanism, and a rod spring is arranged around the push rod, with one end abutting against the pressure force transmission member and the other end abutting against the rear gate. With this structure, when the bed is in the stowed position, the push rod is pushed by the rear gate, generating a biasing force in the rod spring, and this biasing force causes the push rod to press against the rear gate, generating a thrust in the direction of maintaining the closed position. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2024-008669 Summary of the Invention [Problem to be solved by the invention]

[0006] The attitude change suppression mechanism disclosed in Patent Document 1 is not a structure that directly fixes the rear gate, but a structure that applies thrust to the rear gate to suppress attitude change, so if backlash occurs in the support part of the rear gate due to wear of the support shaft, etc., the rear gate can swing by the amount of that backlash. As a result, the rear gate may swing when vibrations occur while the freight vehicle is traveling or when the vehicle accelerates or decelerates.

[0007] In view of the above circumstances, an object of the present invention is to provide a posture change suppression mechanism that can suppress the swinging of the rear gate even when play occurs in the support shaft portion of the rear gate. [Means for solving the problem]

[0008] The first invention is a posture change suppression mechanism that is mounted on a freight vehicle equipped with a loading platform that can change the posture of the vehicle body relative to a chassis frame between a stored posture in which the platform is placed on the chassis frame and a ground-contact posture in which the platform is placed on the ground, and a rear gate that is rotatably supported at the rear of the loading platform around an opening / closing axis along the vehicle width direction and can change the posture relative to the platform between a closed posture in which the platform is upright and an open posture in which the upper end faces rearward of the vehicle body, and that suppresses posture change of the rear gate when the platform is in the stored posture and the closed posture, and a connecting portion that protrudes toward the rear of the vehicle and downward from a surface of the rear panel, a thrust generating portion that applies a thrust force toward the rear of the vehicle to the connecting portion when the vehicle is in the stored position and stops applying the thrust when the vehicle is changed in position or when the vehicle is in the ground contact position; and a sway restricting member that is arranged on the thrust generating portion so as to overlap the opening / closing axis in the vertical direction when the vehicle is in the stored position and protrudes upward, wherein when the vehicle is in the stored position, the sway restricting member comes into contact with the lower part of the rear panel and presses it upward, and the thrust generated by the thrust generating portion and the upward pressing force that the sway restricting member applies to the rear panel suppress changes in position of the rear panel.

[0009] In a second aspect of the present invention, the vehicle body according to the first aspect of the present invention further includes an inclined frame that is displaceable relative to a guide frame fixed to the chassis frame and the loading platform, and is located between the guide frame and the loading platform in the stored posture, and that protrudes in an inclined state toward the rear of the vehicle body in the ground contact posture, with a longitudinal center portion of the inclined frame located at the rear end portion of the guide frame and a front portion of the loading platform located at its rear end portion, and the thrust generating portion includes a push rod that is located in a lower portion of the loading platform, and that is located between the vehicle rear end of the inclined frame and the protruding portion of the connecting portion in the stored posture, with its longitudinal direction oriented parallel to the front-to-rear direction of the vehicle body, and that has its vehicle rear end connected to the protruding portion of the connecting portion so as to be swingable around the axis of a connecting shaft that extends along the vehicle width direction, and that has a large diameter portion formed in one portion with a diameter greater than that of the other portion; the swing restricting member provided on the push rod; and a lower portion of the loading platform that is positioned closer to the push rod than the push rod. a rod spring surrounding the push rod and positioned such that, in the stored posture, one end of the rod main body abuts against the rear plate portion and the other end abuts against the large diameter portion of the push rod; and a rod spring surrounding the push rod and positioned such that, in the stored posture, one end of the rod main body abuts against the rear plate portion and the other end abuts against the large diameter portion of the push rod. When the cargo bed is in the stored posture, the vehicle front end of the rod main body abuts against the oblique frame, the front plate abuts against the vehicle front end of the push rod, and the rod spring contracts more than when the cargo bed is in the ground contact posture, thereby applying the thrust to the connecting portion.

[0010] In a third aspect of the present invention, the vehicle body according to the first aspect of the present invention further includes an inclined frame that is displaceable relative to a guide frame fixed to the chassis frame and the loading platform, and is located between the guide frame and the loading platform in the stored posture, and that protrudes at an angle to the rear of the vehicle body in the ground contact posture, with a longitudinal center portion located at the rear end portion of the guide frame and a front portion of the loading platform located at its rear end portion; and the thrust generating portion includes a push rod that is located below the loading platform, and that is located between the vehicle rear end of the inclined frame and the protruding portion of the connecting portion in the stored posture, with its longitudinal direction parallel to the front-to-rear direction of the vehicle body, and that has its vehicle rear end connected to the protruding portion of the connecting portion so as to be swingable around the axis of a connecting shaft that extends along the vehicle width direction, and that has a vehicle front portion supported by a bracket fixed to the lower portion of the loading platform, and a rear spring receiving plate that is fixed to the vehicle rearward of the portion supported by the bracket; and a rod main body portion located in a lower portion of the cargo bed and disposed forward of the push rod, the front end of which abuts against the vehicle rear end of the tilt frame when the cargo bed is in the stored posture; a spacer having a front end fixed to the vehicle rear end of the rod main body portion and a rear end located rearward of the support portion of the bracket for the push rod; and a pressing force transmission member having a front spring receiving plate fixed to the vehicle rear end of the spacer and through which the push rod passes; and a rod spring surrounding the push rod and having one end abutting against the rear spring receiving plate and the other end abutting against the front spring receiving plate when the cargo bed is in the stored posture, wherein when the cargo bed is in the stored posture, the vehicle front end of the rod main body portion abuts against the tilt frame and the rod spring is compressed more than when the cargo bed is in the ground contact posture, thereby applying the thrust to the connecting portion.

[0011] A fourth invention is an attitude change suppression mechanism described in the third invention, characterized in that at least two of the push rods are fixed in a line in the vehicle width direction, and one rod spring is provided on each of the push rods.

[0012] The fifth invention is a posture change suppression mechanism characterized in that the push rod described in any of the second to fourth inventions has a straight shape when the loading platform is in the ground contact posture, and the central portion in the axial direction deforms into a downwardly convex shape when the loading platform is in the stored posture.

[0013] A sixth invention is an attitude change suppression mechanism characterized in that one of the thrust generating portion and the swing limiting member described in the first invention has a male thread and the other has a female thread, and the amount of upward protrusion can be adjusted by screwing them together. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a posture change suppression mechanism that can suppress the swinging of the rear swing arm even when backlash occurs in the support shaft portion of the rear swing arm. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a side view of a truck according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a structural diagram of the loading platform of the freight vehicle shown in FIG. [Figure 3] 3A to 3C are diagrams illustrating a process of changing the position of the loading platform shown in FIG. 2. [Figure 4] 2A and 2B are a side view and a rear view, respectively, showing the structure of the rear tailgate of the freight vehicle shown in FIG. [Figure 5] 2 is a cross-sectional view of only the loading platform portion of the AA line shown in FIG. 1. FIG. [Figure 6] 2 is a cross-sectional view of only the loading platform portion taken along line BB in FIG. 1. FIG. [Figure 7] 1A and 1B are diagrams showing the structure of a rod unit according to a first embodiment of the present invention. [Figure 8] 3A and 3B are diagrams illustrating a structure of a push unit according to the first embodiment of the present invention. [Figure 9] 3A and 3B are diagrams illustrating a structure of a push unit according to the first embodiment of the present invention. [Figure 10] 6 is an enlarged view showing the structure of a connecting portion between the rod unit and the rear gate shown in FIG. 5. FIG. [Figure 11] 9A to 9C are diagrams illustrating a process in which the rear flap shown in FIG. 8 changes its position to the open position. [Figure 12] 9 is a schematic diagram showing a state in which a swing restricting member acts on the rear tilt portion shown in FIG. 8.

[0023] FIG. [Figure 13] 10A to 10C are diagrams illustrating a process of changing the position of a loading platform according to a second embodiment of the present invention. [Figure 14] 10A and 10B are diagrams showing the structure of a rod unit according to a second embodiment of the present invention. [Figure 15] 10A and 10B are diagrams illustrating a structure of a push unit according to a second embodiment of the present invention. [Figure 16] 10A and 10B are diagrams illustrating a structure of a push unit according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] First Embodiment The rear fan device according to the present invention will be described below with reference to the drawings. It should be noted that the drawings are schematic. Therefore, it should be noted that the relationship between thickness and planar dimensions, ratios, etc. may differ from the actual relationship. The drawings may also include portions where the relationship between dimensions and ratios differ. Furthermore, the embodiments shown below are merely examples of devices and methods for embodying the technical concept of the present invention. The technical concept of the present invention is not limited to the following embodiments in terms of the materials, shapes, structures, arrangements, etc. of the components. In the following explanation, only the part relating to rear tilt will be explained in detail, and other parts will be explained briefly or omitted altogether.

[0017] In the following explanations and drawings, the direction in which the freight vehicle 100 moves forward (the direction in which it travels with the shift selected in D range, etc.) may be referred to as "forward." Similarly, in the following explanations and drawings, the direction in which the freight vehicle 100 moves backward (the direction in which it travels with the shift selected in R range) may be referred to as "rearward," and the left-hand side of the freight vehicle 100 when the driver is sitting in the driver's seat will be referred to as the "left side," and the right-hand side of the freight vehicle 100 when the driver is sitting in the driver's seat will be referred to as the "right side." Therefore, in the following description and drawings, expressions such as "front side of the vehicle," "rear side of the vehicle," "right side of the vehicle," and "left side of the vehicle" may be used in accordance with these definitions.

[0018] <Composition of freight vehicles> The configuration of the freight vehicle 100 will be outlined with reference to FIGS. The freight vehicle 100 is a truck equipped with vehicle loading equipment, and includes a loading platform 102, a chassis frame 200, an inclined frame 300, and a guide frame 400. The rear of the loading platform 102 is provided with a rear gate 2, which will be described in detail later. Although not shown, the chassis frame 200 and the inclined frame 300 are provided with a platform lifting device as an actuator for changing the position of the platform 102. The chassis frame 200 forms the framework of the truck 100, and has a guide frame 400 fixed thereto.

[0019] In the stored posture, which is the posture when the truck 100 is traveling, the positional relationship of the components is such that the inclined frame 300 is located above the guide frame 400, and the loading platform 102 is located further above that. Hereinafter, unless otherwise specified, the truck 100 will be described as being in the stored position.

[0020] <Cargo bed> The structure of the loading platform 102 will be described with reference to FIGS. 2 and 3(a). The loading platform 102 includes front rollers 102a, rear rollers 102b, and a floor plate 106. The floor plate 106 is a plate on which a vehicle is loaded. Further, as will be described in detail later, a rod unit 30 and a push unit 500 are provided on the underside of the floor plate 106 at the rear of the cargo bed 102, aligned in the longitudinal direction of the vehicle.

[0021] The front rollers 102a are cylindrically shaped and are attached to the underside of the floor board 106 (the lower surface in Figure 2), one on the front right side of the vehicle and one on the front left side of the vehicle, so that they can rotate around an axis along the vehicle width direction using front brackets 102c, and a part of each roller protrudes downward beyond the front brackets 102c. The rear rollers 102b are cylindrically shaped and are attached to the underside of the floor plate 106, one on the right rear side of the vehicle and one on the left rear side of the vehicle, so that they can rotate around an axis along the vehicle width direction, and a portion of each roller protrudes downward and rearward from the floor plate 106.

[0022] <Post-incitement> The structure of the rear gate 2 will be described with reference to FIGS. The rear gate 2 is a plate that also serves as a ramp when loading cargo onto the loading platform 102, and is attached to the rear end of the loading platform 102 in a state in which it can swing around an opening / closing axis 3 that runs along the width direction of the vehicle relative to the loading platform 102. By swinging the rear gate 2 relative to the loading platform 102, it is possible to change the position of the rear gate 2 relative to the loading platform 102 between a closed position and an open position.

[0023] The closed position is a position in which the rear gate 2 stands vertically relative to the floor board 106, as shown in Figures 3(a) and 4(a). When the truck 100 is traveling, the rear gate 2 is maintained in the closed position by a position change suppression mechanism, which will be described later. In the open position, the upper end of the rear gate 2 faces rearward of the vehicle and lies horizontally, as shown in Fig. 3(e). Specifically, it is a position that is approximately parallel to the floor board 106, and the position can be changed manually when loading and unloading cargo.

[0024] As shown in Fig. 4(b), opening / closing shaft support portions 6a are provided at multiple locations on the lower part of the rear door frame 2, and the opening / closing shaft 3 is fitted into each of them. Specifically, two opening / closing shaft support portions 6a are provided on each of the right and left sides of the vehicle, with the center of the vehicle width as the boundary, and are arranged line-symmetrically when viewed from the front-to-rear direction of the vehicle. The two opening / closing shaft support portions 6a provided on the left side of the vehicle and the one opening / closing shaft support portion 6a provided on the outer side of the right side of the vehicle width direction are inverted U-shaped members fixed to the lower part of the rear door frame 2. On the right side of the vehicle, at the center in the vehicle width direction, an opening / closing shaft support part 6b is formed on the connecting part 2a, which will be described next. All of the opening / closing shaft support parts 6a, 6b are formed so that when the opening / closing shafts 3 are fitted into each, all of the opening / closing shafts 3 are arranged coaxially.

[0025] The connecting portion 2a is a U-shaped plate extending toward the rear of the vehicle from the surface of the rear gate 2 that faces the rear of the vehicle when in the closed position (hereinafter referred to as the rear surface 2b), and is fixed so that its upper portion is located below the rear surface 2b and its protruding portion in the lateral direction is located on the underside of the rear gate 2. Therefore, the lower portion of the connecting portion 2a protrudes toward the rear and downward of the vehicle relative to the rear gate 2. The connecting portions 2a are fixed in two with their surfaces facing each other, and the opening / closing shaft support portion 6a is formed on the protruding portion in the lateral direction so as to be coaxial with the other opening / closing shaft 3. Furthermore, a cylindrical opening / closing shaft bracket 2c is fixed between the opposing surfaces of the connecting portions 2a so as to be coaxial with the opening / closing shaft 3.

[0026] The position where the connecting portion 2a is fixed is also a position where it overlaps with the axes of a rod unit 30 and a push unit 500 (described later) when viewed from the vertical direction, and when viewed from the vehicle width direction, the portion that protrudes downward overlaps with part of the rod unit 30. A circular through-hole is formed in the protruding portion in the direction along the vehicle width direction, and the protruding portion is connected to the end of a push rod 31 (described later) by a connecting shaft 5. The connecting shaft 5 is fitted so that its axial direction is parallel to the axial direction of the opening / closing shaft 3.

[0027] <Inclined frame> The structure of the inclined frame 300 will be described with reference to FIGS. The main body of the inclined frame 300 is a frame-like structure in which two members, each with a roughly C-shaped cross section and elongated along the fore-and-aft direction of the vehicle, are arranged on the right and left sides of the vehicle with their openings facing outward in the vehicle width direction, and are fixed together by frame connection parts 307 and connecting members (not shown) that connect the rear portions of the vehicles together. The inclined frame 300 includes a first lower surface roller 304, a second lower surface roller 305, and a frame connecting portion 307 in addition to the main body portion.

[0028] The interior of the main body of the inclined frame 300 is a running surface on which the front rollers 102a of the loading platform 102 run. Furthermore, the C-shaped member has an inclined portion 302 that increases in height toward the rear of the vehicle, from about one-tenth of its total length at the front of the vehicle to about three-tenths of its total length. Therefore, the vehicle front portion 301 and the vehicle rear portion 303, which are sandwiched by the inclined portion, are substantially parallel to each other in the longitudinal direction, but the vehicle rear portion 303 is located at a higher position.

[0029] The first lower surface roller 304 is formed in a cylindrical shape and is attached to the lower surface of the central portion of the guide lane in the longitudinal direction so as to be rotatable around an axis of rotation along the vehicle width direction using a first lower surface bracket 308, with a portion of it protruding downward beyond the first lower surface bracket 308. The second lower surface roller 305 is formed in a cylindrical shape and is attached to the rear of the vehicle from the first lower surface roller 304 using a second lower surface bracket 309 so as to be rotatable around an axis along the vehicle width direction, with a portion of it protruding downward beyond the second lower surface bracket 309.

[0030] <Guide frame> The structure of the guide frame will be described with reference to FIGS. The guide frame 400 is fixed to the chassis frame 200, and includes a horizontal guide portion 401 and an inclined guide portion 402 as a main body portion.

[0031] The horizontal guide portions 401 are members having a generally C-shaped cross section that are elongated along the vehicle longitudinal direction, and are disposed one on each of the right and left sides of the vehicle with their openings facing the center in the vehicle width direction. The interior is a running surface on which the first lower surface roller 304 and the second lower surface roller 305 of the inclined frame 300 run. The inclined guide portion 402 is continuous with the rear end of the horizontal guide portion 401 (the right end portion in FIG. 2), and is inclined downward as it approaches the rear of the vehicle in a side view. The inside of the inclined guide portion is a running surface like the inside of the horizontal guide portion 401, but in reality, only the second lower surface roller 305 runs on it.

[0032] The guide roller 403 is formed in a cylindrical shape, is arranged at the rear end of the horizontal guide portion 401, and is attached so as to be rotatable around an axis along the vehicle width direction, with a portion of it protruding upward beyond the horizontal guide portion 401.

[0033] The holding hook 404 is disposed at the front end of the horizontal guide portion 401 (the left end portion in FIG. 2), and protrudes upward from the horizontal guide portion 401. Furthermore, the retaining hook 404 is formed in a shape that allows it to catch a lock pin (not shown) attached to the loading platform 102.

[0034] <Posture change suppression mechanism> The attitude change suppression mechanism will be described with reference to FIG. 3 and FIG. 7 to FIG. The truck 100 is equipped with a rod unit 30 and a push unit 500 as thrust generating units. When the bed 102 is in the stored position, the rod unit 30 and the push unit 500 apply a thrust force toward the rear of the vehicle to the connecting portion 2a of the rear gate 2. The push unit 500 is a pressing force transmitting member.

[0035] (rod unit) As shown in FIG. 7, the rod unit 30 includes a push rod 31, a rod spring 32, and a connecting member 33. The push rod 31 is a cylindrical member extending in the front-to-rear direction of the vehicle. A spring receiving plate 34, which is a large-diameter portion formed with a larger diameter than the rest of the push rod, is formed in a position approximately one-third of the vehicle's rear. The rod spring 32 is disposed on the front side of the vehicle across the spring receiving plate 34 so as to surround the push rod 31, with the rear end of the rod spring 32 abutting against the spring receiving plate 34. The front end of the rod spring 32 abuts against a rear plate portion 543, which will be described later.

[0036] A connecting member 33 is fixed to the rear end of the push rod 31, and the connecting member 33 is connected to the connecting portion 2a of the rear door 2 by a connecting shaft 5 so as to be swingable around an axis along the vehicle width direction. 8 and 9, a rod bracket 35 is provided at the front end of the push rod 31, through which the push rod 31 passes and supports it. The rod bracket 35 is a square tube-shaped member that is open at the top and bottom, and is fixed to the bottom of the cargo bed 102 via a plate portion 35a.

[0037] Through holes for supporting the push rod 31 are formed on the vehicle front and rear sides of the rod bracket 35. The through hole 35b on the vehicle rear side is circular in shape to match the cross-sectional shape of the push rod 31, but the through hole 35c on the vehicle front side is oval in shape and wider in the vertical direction than the cross-sectional shape of the push rod 31 for reasons that will be described later.

[0038] As shown in Figure 7, the connecting member 33 has a screw hole 36 with a female screw thread formed along the vertical direction at a position that overlaps with the opening / closing shaft 3 in the vertical direction when the rear gate 2 is in the closed position.

[0039] Although details are omitted, the rod unit 30 is provided with a hook unit 38 that keeps the rear gate 2 in a closed position by restricting the movement of the push rod 31 toward the front of the vehicle. Although not shown, the worker can unlock the hook unit 38 by operating a lever provided on the side of the loading platform 102, allowing the push rod 31 to operate and the position of the rear gate 2 to be changed.

[0040] The rod unit 30 is provided with a length adjustment mechanism 39 at the front end of the push rod 31, allowing for length adjustment. The length adjustment mechanism 38 is used to adjust the thrust applied to the rear gate 2.

[0041] (Push unit) 8 and 9, the push unit 500 includes a rod main body 510 and a pipe end 540. Note that Fig. 8 shows a state in which no thrust is generated, and Fig. 9 shows a state in which thrust is generated.

[0042] The rod main body 510 is a member that is long along the vehicle longitudinal direction, and is formed in a cylindrical shape with a square cross section. 8 and 9, the rod main body 510 is disposed below the bed 102 via a retaining bracket 520 so that, when viewed from the front-to-rear direction of the truck 100, two of the four sides forming the outer periphery face downward and the remaining two sides face upward. Note that in addition to the retaining bracket shown in the drawings, another retaining bracket is also provided on the front side of the vehicle, and holds the rod main body 510 movably along the front-to-rear direction of the vehicle.

[0043] A pipe end 540 is fixed to the end of the rod main body 510 on the vehicle rear side. The pipe end 540 includes a front plate 542, a rear plate 543, a first side plate 544, and a second side plate 545, each of which is a plate-shaped member, and these members are assembled into a box shape with open top and bottom. The rod main body 510 is fixed to the front plate 542.

[0044] The thickness direction of the front plate portion 542 is parallel to the front-rear direction of the truck 100. The thickness direction of the rear plate portion 543 is also parallel to the longitudinal direction of the truck 100, and is fixed to the first side plate portion 544 and the second side plate portion 545 at a distance from the front plate portion 542. In other words, the front plate portion 542 is disposed at a distance from the rear plate portion 543 along the longitudinal direction of the truck 100. In addition, a circular rear plate-side through-hole is formed in the rear plate portion 543, and the push rod 31 passes through it.

[0045] The distance between the rear plate portion 543 and the front plate portion 542 is set to a value that compresses the rod spring 32 compared to the no-load state when the rear gate 2 is in the closed position and the loading platform 102 is in the stored position. In other words, when the loading platform 102 is in the stored position, the rod spring 32 contracts more than when the loading platform 102 is in the ground-contact position. Here, the length by which the rod spring 32 is contracted is the length by which the pipe end 540 and the rod main body 510 are pressed against the inclined frame 300 by the restoring force generated by the contracted rod spring 32 .

[0046] (Swing restriction member) 10, a swing restricting member 37 having a male screw formed on the outer periphery is screwed into a screw hole 36 formed in the connecting member 33. In this embodiment, a so-called set screw is used for the swing restricting member 37. A part of the swing restricting member 37 protrudes from the upper part of the connecting member 33. The amount of protrusion can be adjusted by rotating the swing restricting member around its own axis.

[0047] <Operation / effect> (Behavior when changing posture) The operation of the platform 102 when its posture changes will be described with reference to FIG. When the freight truck 100 is traveling, the bed 102 is in the stored position shown in Fig. 3(a), and the rear gate 2 is also in the closed position shown in the same figure. When loading or unloading vehicles, the bed 102 is changed to the grounded position shown in Fig. 3(e), and the rear gate 2 is also changed to the open position shown in the same figure. Next, the operation when changing the posture will be described in detail.

[0048] 3(a), when the loading platform 102 is in the stowed position, the front end of the push rod 31 abuts against the rear end of the rod main body 510 via the front plate 542, and the front end of the rod main body 510 abuts against the rear end of the tilting frame 300. At this time, a propulsive force is applied to the loading platform 102 by the loading platform lifting device in a direction that changes the position to the stowed position, i.e., toward the front of the vehicle. 10, the rear gate 2 has the connecting shaft 5 connected to the connecting member 33 positioned below the opening / closing shaft 3, which serves as the swing axis when opening and closing. Therefore, the reaction force of the thrust toward the front of the vehicle that the bed lifting device applies to the bed is transmitted to the connecting shaft 5 via the tilting frame 300, the rod main body 510, and the push rod 31, and a thrust toward the rear of the vehicle, i.e., a thrust in a direction that causes the rear gate 2 to maintain the closed position, is applied.

[0049] Furthermore, while the bed 102 is in the stowed position, the rod spring 32 is in a contracted state, as shown in FIG. 9 . Therefore, a thrust toward the rear of the vehicle acts on the push rod 31 due to the restoring force of the rod spring 32. This thrust due to the restoring force acts even if the bed rattles in the fore-and-aft direction of the vehicle while the truck 100 is traveling. That is, if the bed 102 moves toward the rear of the vehicle due to rattle, a small gap is created between the push rod 31, the rod main body 510, and the tilt frame 300, allowing the rear gate 2 to swing by the amount of this gap. However, the repulsive force of the rod spring 32 acts on the push rod 31 and the rod main body 510, causing them to move away from each other in the fore-and-aft direction of the vehicle, so that the thrust toward the rear of the vehicle can be maintained even in such a case.

[0050] 3(b), when the posture change of the bed 102 starts, the bed 102 moves toward the rear of the vehicle while the tilting frame 300 is stopped. As a result, the front end of the rod main body 510 moves away from the rear end of the tilting frame 300, and the front end of the push rod 31 also moves away from the rear end of the rod main body 510. After that, when the rod spring 32 is fully extended, the thrust applied to the rear gate 2 is also released. Even after the application of the thrust is released, the position of the push rod 31 is maintained by the hook unit 38, so the closed position of the rear gate 2 is maintained.

[0051] Next, as shown in FIG. 3(c), with the inclined frame 300 stopped, the loading platform 102 projects to the rear side of the vehicle body, and the rear rollers 102b shown in FIG. 2 come into contact with the ground. Thereafter, the tilting frame 300 operates. The tilting frame moves while tilting so that its rear end approaches the ground until its central portion is positioned at the rear end of the chassis frame 200.

[0052] 3(d), the tilting frame 300 is operated until the entire loading platform 102 is positioned at the rear of the chassis frame 200, thereby placing the platform 102 in a ground contact position. At this time, the tilting frame 300 is operated and tilted, thereby lowering the front of the platform 102. Although not shown, a rear bumper equipped with a deformation mechanism capable of deforming until its underside touches the ground is located at the lower front portion of the platform 102, and when the platform has completed its positional change to the ground contact position, the front of the platform 102 is supported by the rear bumper.

[0053] 3(d), after the loading platform 102 is in the ground contact position, the position of the rear gate 2 can be changed by unlocking the hook unit 38 shown in Fig. 7. In this state, the worker can swing the rear gate 2 backward so that its end touches the ground, causing the rear gate 2 to assume the open position.

[0054] Thereafter, the automobiles serving as cargo are loaded or unloaded from the rear of the vehicle by self-propelling or using a winch, etc. To load cargo, the automobiles serving as cargo are secured to the loading platform using a fixture. The above procedure is then reversed to place the rear gate 2 in the closed position, and the loading platform 102 in the stowed position. The hook unit 38 acts like a ratchet mechanism, and is automatically locked when the rear gate 2 is changed from the open position to the closed position.

[0055] (Operation of swing restricting member) The operation of the thrust generating unit and the swing restricting member 37 when changing the attitude will be described with reference to Figures 10 to 12. Among the arrows shown in Figure 12, the large arrows with white interiors indicate the thrust generated by the thrust generating unit and the force acting on the rear gate 2 by the thrust, and the small arrows indicate that the opening / closing shaft 3 and the connecting shaft 5 are pressed against their respective support portions.

[0056] As shown in FIG. 10, when the loading platform 102 is in the stored position and the rear gate 2 is in the closed position, the tip of the rocking restriction member 37 abuts against the opening / closing shaft bracket 2c of the connecting portion 2a.

[0057] 11, while the rear door swing arm 2 is not in the closed position, the push rod 31 is in a position in which the end on the vehicle rear side is slightly lowered. This is because, when the rear door swing arm 2 swings, the connecting shaft 5 moves along a circular trajectory centered on the opening / closing shaft 3. The aforementioned through-hole 35c formed on the vehicle front side of the rod bracket 35 is formed in an elliptical shape to accommodate the inclination of the push rod 31.

[0058] With this structure, when the rear gate 2 is in the open position or while it is changing its position, the rocking restriction member 37 is separated from the rear gate 2, and only when it is in the closed position does its upper end abut on the bracket portion of the rear gate 2 and press upward. Note that this pressing force is the thrust generated by the push rod but with a changed direction.

[0059] The opening / closing shaft bracket 2c is pushed up by the pressing force generated by the swing restricting member 37. Since the opening / closing shaft bracket 2c is fixed to the connecting portion 2a, the entire rear gate 2 is pushed up. Therefore, as shown in FIG. 12, the opening / closing shaft 3 is pressed against the lower part of its supporting portion, and the connecting shaft 5 is pressed against the lower part of its supporting portion.

[0060] Minute gaps occur between the opening / closing shaft 3 and the connecting shaft 5 and their respective support parts due to dimensional tolerances between the shafts and the support holes provided for fitting the respective shafts, and due to wear of the members caused by the swinging of the rear gate 2. Note that the gaps between the opening / closing shaft 3 and the connecting shaft 5 and their respective support parts shown in Figure 12 are exaggerated for ease of visual understanding. Such a small gap can cause the rear tailgate 2 to rattle when the freight truck 100 is traveling.

[0061] Therefore, the positional relationship between the opening / closing shaft 3, the connecting shaft 5, and the rear gate 2 is fixed by pressing them against the support parts using the swing restricting member 37. Therefore, regardless of the size or presence of a minute gap, the rear gate 2, the opening / closing shaft 3, and the connecting shaft 5 cannot be displaced relative to each other.

[0062] The amount of protrusion of the rocking restricting member 37 is set to such an extent that the push rod 31 is deflected by the reaction force of the rocking restricting member 37 pressing against the rear gate 2 when the loading platform 102 is in the stored position and the rear gate 2 is in the closed position. When the protrusion amount is set in this manner, the push rod 31 is supported at both ends, and the rocking restriction member 37 is located closer to the axial center than the connecting shaft 5, which is the support part. Therefore, the push rod 31 shown in Figure 7 is in a state where the straight shape is distorted, with the center part deformed into a downwardly convex, arched shape.

[0063] <Effects of the First Embodiment> By providing the swing-restricting member 37 at the end of the thrust generating unit, it is possible to suppress rattle of the rear gate 2 even if the opening / closing shaft 3 and the connecting shaft 5 wear and a gap occurs between them and the support parts. Furthermore, even if vibrations are applied to the loading platform 102 when it is in the stowed position, the rear gate is pressed from two directions by the thrust generating unit and the swing-restricting member 37, so it has a high ability to suppress rattle.

[0064] When the rear gate 2 is changed from the closed position to the open position, the thrust generating portion moves the connecting shaft 5 toward the front of the vehicle while moving slightly downward, and the push rod 31 connected to the connecting shaft 5 also moves in the same manner. Therefore, in the stored position where thrust is generated in the push rod 31, the swing restricting member 37 presses the opening / closing shaft bracket 2c, but the swing restricting member 37 does not press the opening / closing shaft 3 at any position other than the stored position. With this structure, the rocking restriction member 37 generates a pressing force in conjunction with the operation of the thrust generating portion, so there is no need to provide a separate structure for generating a pressing force, and the structure can be made less complicated.

[0065] By bending the push rod 31 in advance, the restoring force of the bending is used as a pressing force for the swing-restricting member 37, making it possible to increase the force that prevents the rear swing lever 2 from swinging. Furthermore, even if the rear swing lever 2 swings, the pressing force is maintained by the elasticity of the push rod 31, improving the ability to damp repeated swings.

[0066] Since the amount of protrusion of the swing restricting member 37 is adjustable, it is easy to adjust the pressing force according to the individual differences of the freight vehicle 100 and the degree of wear of the opening / closing shaft 3.

[0067] Second Embodiment The second embodiment will be described with reference to FIGS. 13 to 16, but only the structural parts that differ from the first embodiment will be described, and a description of the parts that have the same structure as the first embodiment will be omitted. Specifically, the second embodiment differs from the first embodiment in the structures of the rod unit 30 and the push unit 500.

[0068] <Rod unit> As shown in Figures 14 to 16, the rod unit 40 of the second embodiment includes two push rods 41, two rod springs 42, a connecting member 43, a rear spring support plate 44, a bracket 45, a rod fixing member 48, a hook unit 49, and a locking plate 50. As in the first embodiment, a screw hole 46 is formed inside the connecting member 43, and a swing restricting member 47 is screwed into the screw hole 46.

[0069] The push rods 41 are arranged side by side with their axial directions extending in the vehicle longitudinal direction and parallel to the vehicle width direction, and their rear ends are fixed by rod fixing members 48. The rod fixing members 48 fix the rear ends of the push rods 41 at a distance in the center that allows a hook member 49 and a locking plate 50 to be accommodated, and the locking plate 50 is accommodated in this space. The front side of the locking plate 50 engages with a hook unit 49 that secures the rear door flap 2 in the closed position. The upper surface of the locking plate 50 abuts against the tip of the hook unit 49 when the rear door flap 2 changes position and when it is in the open position. Therefore, when the rear door flap 2 changes position, part of the hook unit 49 slides on the upper surface of the locking plate 50.

[0070] A rear spring receiving plate 44 is fixed to the vehicle forward of the hook unit 49. The rear spring receiving plate 44 is a plate-like member that is fixed to span the left and right push rods 41 and is elongated in the vehicle width direction with its thickness aligned in the front-to-rear direction of the vehicle, and is against which the rear ends of the rod springs 42 abut.

[0071] One rod spring 42 is provided for each push rod 41 so as to surround the periphery of the push rod, and is disposed in front of the rear spring receiving plate 44. The rod spring 42 is formed to a length such that a portion of the push rod 41 protrudes from the end of the rod spring 42 on the front side of the vehicle.

[0072] The bracket 45 has a vertical portion on the front side of the vehicle, and a support plate 45a for supporting the push rod 41 passing through the vertical portion is fixed to the vertical portion. Although not shown, the support plate 45a has through holes formed in a line in the vehicle width direction. Specifically, a through hole for passing a spacer 622 (described later) is formed in a central portion in the vehicle width direction, and through holes for mounting bushes arranged in the vehicle width direction on either side of the central portion for supporting the rod 41 so that the rod 41 can slide along the vehicle front-rear direction are formed. Therefore, the bushes are mounted at intervals equal to the intervals between the push rods 41 connected by the rod fixing member 48.

[0073] <Push unit> A push unit 600 according to the second embodiment includes a rod main body 610 in the shape of a square tube, and an end portion 620 fixed to the vehicle rear end of the rod main body. The rod main body 610 is supported by a bracket 611 so as to be movable in the front-rear direction of the vehicle, with the upper and lower surfaces oriented parallel to the vehicle width direction.

[0074] The end portion 620 includes a fixing plate portion 621 , a spacer 622 , and a front spring receiving plate 623 . The fixed plate portion 621 is a plate-shaped member fixed to the rear end portion of the rod main body portion 610. The spacer 622 is an E-shaped bar material that is open on the outer side in the vehicle width direction, with its length oriented in the vehicle front-rear direction and its front end fixed to the fixing plate portion 621. The front spring receiving plate 623 is a plate-shaped member whose thickness is oriented in the vehicle longitudinal direction and is elongated in the vehicle width direction, and has through holes formed in the front-rear direction of the vehicle that are aligned in the vehicle width direction. The through holes have a diameter larger than the outer diameter of the push rod 41 and are formed at equal intervals as the intervals at which the left and right push rods 41 are fixed, allowing the push rod 41 to pass through.

[0075] <Operation / effect> The operation and function of the rod unit 40 and the push unit 600 according to the second embodiment will be described with reference to FIGS.

[0076] As shown in FIG. 13(a), when the loading platform 102 is in the stowed position, the vehicle front end of the rod main body 610 abuts against the inclined frame 300, and a thrust is applied toward the rear of the vehicle. This thrust causes the front spring receiving plate 623 to press against the rod spring 42, shortening it. A restoring force is generated in the shortened rod spring 42, but because the rod main body 610 abuts against the inclined frame 300, it is unable to move further toward the front of the vehicle. Therefore, the restoring force of the rod spring 42 becomes a thrust that swings the rear gate 2 to the closed position.

[0077] The rod unit 40 and push unit 600 according to the second embodiment differ from those of the first embodiment in that the push rod 41 does not abut against the push unit 600, and the thrust that swings the rear gate 2 to the closed position is generated solely by the restoring force of the rod spring 42.

[0078] 13(b), when the posture of the bed 102 starts to change, the bed 102 moves toward the rear of the vehicle while the tilting frame 300 is stopped. As a result, the front end of the rod main body 610 moves away from the rear end of the tilting frame 300, and the front spring receiving plate 623 moves toward the front of the vehicle. This causes the rod spring 42 to stretch, weakening the restoring force. Even after the application of the thrust is released, the position of the push rod 41 is maintained by the hook unit 49, so the closed position of the rear gate 2 is maintained. The subsequent operations from FIG. 13(c) to FIG. 13(d) are the same as those in the first embodiment, and therefore will not be described.

[0079] <Effects of the second embodiment> The thrust generating unit according to the second embodiment generates a thrust that causes the rear gate 2 to assume the closed position using only the restoring force of the rod spring 42. Therefore, a length adjustment mechanism for the push rod 31, which is essential for a structure that causes the push rod 31 to abut against the push unit 500, is not required. The restoring force of the thrust generating portion according to the second embodiment can be adjusted by selecting the length and spring constant of the rod spring 42, which reduces the effort required for adjustment during manufacturing and maintenance.

[0080] Furthermore, the thrust generating unit according to the second embodiment includes two rod springs 42. Therefore, it is possible to use a spring with a smaller spring constant than in a structure including only one rod spring 32. Therefore, it is possible to reduce the load applied to each rod spring 42, and therefore it is possible to suppress wear of the rod spring 42.

[0081] Furthermore, by providing a plurality of rod springs 42, it becomes possible to easily set the spring constant of the rod unit 40. That is, if there is only one rod spring 42, it is necessary to select one that satisfies the desired spring constant and also satisfies the limitations of the placement space and length, but by providing a plurality of rod springs 42, rod springs 42 with different spring constants can be used in combination, making it easy to design a rod unit 40 that satisfies the limitations and is set to the desired spring constant. In addition, this structure makes it easy to design a system that can accommodate changes in the thrust required to maintain the closed position due to variations in the shape of the rear gate 2 or in accessories such as a backup camera. Furthermore, even if thrust adjustment becomes necessary later, thrust adjustment can be easily performed by combining rod springs 42 with different spring constants.

[0082] The two push rods 41 according to this embodiment are provided to share the push unit 600. This makes it easier to use rod springs 42 with different spring constants than when the push rods 41 are provided independently on the left and right sides of the vehicle. This is because, if rod springs 42 with different spring constants were provided on the left and right sides of the vehicle, different thrust forces would be applied to the left and right rear end tailgate 2, which could cause uneven wear on the rotating shaft 3 and the connecting shaft 5. Furthermore, the different thrust forces on the left and right sides of the rear end tailgate 2 would make it easier for loads to be applied to the push rods 41 and rod springs 42 in directions other than the axial direction. Therefore, in the case of a thrust generating unit in which the push rods 42 are provided independently on the left and right sides of the vehicle, a structure to address this problem would be necessary, which would increase manufacturing and maintenance costs. However, the structure shown in this embodiment makes it possible to select the rod spring 42 without causing such problems.

[0083] <Modification> In the embodiment, the swing restricting member 37 is a set screw that is screwed into the screw hole 36 of the connecting member 33, but in the practice of the present invention, the structure of the swing restricting member 37 is not limited to this form. For example, the swing restricting member 37 may be fixed to the connecting member 33 . Furthermore, the push rod 31 does not necessarily have to deform into a downwardly convex shape when the loading platform 102 is in the stored position, as long as the swing restricting member 37 presses the loading platform 102 upward.

[0084] In the embodiment, the thrust generating unit has a structure including a push rod 31 and a push unit 500, but in implementing the present invention, the thrust generating unit does not necessarily have to have such a structure, and it is sufficient if the thrust generating unit has a structure that can generate thrust toward the rear of the vehicle at the bottom of the rear gate 2 sandwiching the opening / closing shaft 3. [Explanation of symbols]

[0085] 2...rear gate, 2a...connecting portion, 2b...rear surface, 2c...opening / closing shaft bracket, 3...opening / closing shaft, 5...connecting shaft, 30, 40...rod unit, 31, 41...push rod, 33, 43...connecting member, 37, 47...swing restricting member, 100...freight vehicle, 102...loading platform, 200...chassis frame, 300...inclined frame, 400...guide frame, 500, 600...push unit

Claims

1. a cargo bed capable of changing the posture of the vehicle body relative to a chassis frame between a stored posture in which the cargo bed is disposed on the chassis frame and a ground-contact posture in which the cargo bed is disposed on the ground; and a rear tailgate supported at the rear of the cargo bed so as to be rotatable about an opening / closing axis along the vehicle width direction, the rear tailgate being capable of changing the posture of the rear tailgate relative to the cargo bed between a closed posture in which the cargo bed is upright and an open posture in which the upper end of the rear tailgate faces rearward of the vehicle body, the posture change suppression mechanism being mounted on a freight vehicle and configured to suppress posture changes of the rear tailgate when the cargo bed is in the stored posture and the closed posture, a connecting portion, a portion of which protrudes rearward and downward from the rearward-facing surface of the rear gate, on a surface of the rear gate that faces the rear side of the vehicle body when in the closed position; a thrust generating unit that applies a thrust force toward the rear of the vehicle to the connecting unit when the vehicle is in the stored posture and stops applying the thrust when the vehicle is in a posture change or in the ground contact posture; a swing restricting member that is disposed on the thrust generating section so as to overlap with the opening / closing shaft in the vertical direction when in the stored posture, and that protrudes upward, In the stored position, the rocking restricting member contacts the lower portion of the rear gate and presses it upward, an attitude change suppression mechanism that suppresses attitude change of the rear swing arm by the thrust generated by the thrust generating unit and an upward pressing force applied to the rear swing arm by the swing restricting member;

2. The vehicle body further includes an inclined frame that is displaceable relative to a guide frame fixed to the chassis frame and the loading platform, that is located between the guide frame and the loading platform in the stored posture, that protrudes in an inclined state toward the rear of the vehicle body in the ground contact posture, that has a longitudinal center portion located at the rear end of the guide frame and that has a front portion of the loading platform located at its rear end, The thrust generating unit includes: a push rod located under the loading platform, the push rod being disposed between the vehicle rear end of the tilting frame and the protruding portion of the connecting portion when in the stowed posture, with the length direction being parallel to the front-to-rear direction of the vehicle body, the vehicle rear end being connected to the protruding portion of the connecting portion so as to be swingable about the axis of a connecting shaft that is aligned in the vehicle width direction, and the push rod having a large diameter portion formed in a part thereof that is larger in diameter than other portions; the swing restricting member provided on the push rod; a pressing force transmission member including: a rod main body portion located in a lower portion of the cargo bed, the rod main body portion being arranged further forward than the push rod and having a front end portion abutting against a rear end portion of the oblique frame when in the stored posture; a front plate portion fixed to the rear end portion of the rod main body portion and against which a front end portion of the push rod abuts; and a rear plate portion fixed to the front plate portion at a position spaced from the front plate portion toward the rear of the vehicle and through which the push rod passes; a rod spring that surrounds the push rod and is positioned such that one end of the rod spring abuts against the rear plate portion and the other end of the rod spring abuts against the large diameter portion of the push rod when the push rod is in the stored position; 2. The posture change suppression mechanism according to claim 1, wherein, when the loading platform is in the stored posture, the vehicle front end of the rod main body abuts against the inclined frame, the front plate abuts against the vehicle front end of the push rod, and the rod spring contracts more than when the loading platform is in the ground contact posture, thereby applying the thrust to the connecting portion.

3. The vehicle body further includes an inclined frame that is displaceable relative to a guide frame fixed to the chassis frame and the loading platform, that is located between the guide frame and the loading platform in the stored posture, that protrudes in an inclined state toward the rear of the vehicle body in the ground contact posture, that has a longitudinal center portion located at the rear end of the guide frame and that has a front portion of the loading platform located at its rear end, the thrust generating unit being a push rod located in a lower portion of the loading platform, the push rod being disposed in a position between a vehicle rear end of the oblique frame and the protruding portion of the connecting portion when the loading platform is in the stored posture, with the length direction being parallel to the front-to-rear direction of the vehicle body, the end on the vehicle rear side being connected to the protruding portion of the connecting portion so as to be swingable about the axis of a connecting shaft that is aligned in the vehicle width direction, the front portion of the push rod being supported by a bracket that is fixed to the lower portion of the loading platform, and a rear spring receiving plate being fixed to the vehicle rearward of the portion supported by the bracket; the swing restricting member provided on the push rod; a pressing force transmission member including: a rod main body portion located in a lower portion of the cargo bed and disposed further forward of the push rod than the push rod, the front end of which abuts against the vehicle rear end of the oblique frame when in the stored posture; a spacer having a front end fixed to the vehicle rear end of the rod main body portion and a rear end located further rearward of the vehicle than the support portion of the bracket for the push rod; and a front spring receiving plate fixed to the vehicle rear end of the spacer and through which the push rod passes; a rod spring that surrounds the push rod and has one end abutting against the rear spring receiving plate and the other end abutting against the front spring receiving plate when the push rod is in the stored position; 2. The posture change suppression mechanism according to claim 1, wherein when the loading platform is in the stored posture, the vehicle front end of the rod main body abuts against the inclined frame, causing the rod spring to contract more than when the loading platform is in the ground contact posture, thereby applying the thrust to the connecting portion.

4. At least two of the push rods are fixed side by side in the vehicle width direction, 4. The attitude change suppression mechanism according to claim 3, wherein the rod spring is provided for each of the push rods.

5. The posture change suppression mechanism according to any one of claims 2 to 4, characterized in that the push rod has a straight shape when the loading platform is in the ground contact posture, and the central portion in the axial direction is deformed into a downwardly convex shape when the loading platform is in the storage posture.

6. 2. The attitude change suppression mechanism according to claim 1, wherein a male thread is provided on one of the thrust generating portion and the swing restricting member, and a female thread is provided on the other, and the amount of upward protrusion can be adjusted by screwing them together.

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