trailer

Abstract

To facilitate an operation when a trailer is connected to a dolly.SOLUTION: A trailer, which is used by being connected to a dolly serving as one of connection objects, comprises first and second axles. The trailer has an actuator which is provided for the first axle positioned ahead of the second axle and which moves the first axle to an ascent position and a descent position. The trailer has a control device which is provided with a detection part for detecting that the connection object is the dolly and which makes the first axle arranged in the decent position by controlling the actuator when the connection object is the dolly.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a trailer having a first axle and a second axle.

Background Art

[0002] As a trailer towed by a semi-tractor or a full-tractor, there is a semi-trailer having a kingpin connected to a coupler. When towing a semi-trailer by a semi-tractor, the kingpin is connected to the coupler of the semi-tractor. Further, when towing a semi-trailer by a full-tractor, the kingpin is connected to the coupler of a dolly connected to the full-tractor (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, when towing a semi-trailer by a full-tractor, since a dolly is interposed between the full-tractor and the semi-trailer, the overall length from the full-tractor to the semi-trailer becomes long. Thus, since the increase in the overall vehicle length is a factor in expanding the inside turning radius, the driving operation when the semi-trailer is connected to the dolly has been difficult.

[0005] An object of the present invention is to facilitate the driving operation when a trailer is connected to a dolly.

Means for Solving the Problems

[0006] A trailer according to one embodiment is used in conjunction with a dolly, which is one of the objects to be connected, and comprises a first axle and a second axle, wherein the first axle is located in front of the second axle and has an actuator that moves the first axle between a raised position and a lowered position, and a detection unit that detects that the object to be connected is the dolly, and a control device that controls the actuator to position the first axle in the lowered position when the object to be connected is the dolly. [Effects of the Invention]

[0007] According to one aspect of the present invention, the operation of connecting a trailer to a dolly can be made easier. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows a semi-trailer according to Embodiment 1. [Figure 2] This diagram shows the process of connecting a full tractor to a semi-trailer. [Figure 3] This diagram shows the connection between a full tractor and a semi-trailer. [Figure 4] This diagram shows the process of connecting a semi-tractor and a semi-trailer. [Figure 5] This diagram shows the connection between a semi-tractor and a semi-trailer. [Figure 6] This figure shows the axle and its vicinity within range X6 of Figure 1. [Figure 7] This figure shows an example of a control system for an axle lifting device. [Figure 8] (A) and (B) are diagrams showing the wedge apparatus in range X8 as shown in Figure 1. [Figure 9] Figure 3 shows the dolly and semi-trailer from the direction of arrow X9. [Figure 10] This figure shows an example of a control circuit for a wedge device. [Figure 11] (A) and (B) are diagrams showing the connection status of the power cables when the dolly is attached. [Figure 12] (A) and (B) are diagrams showing the connection status of the power cable when connecting a semi-trailer. [Figure 13] It is a flowchart showing an example of the execution procedure of forced descent control. [Figure 14] (A) and (B) are diagrams showing the execution status of forced descent control. [Figure 15] (A) to (D) are diagrams showing the execution status of forced descent control in Embodiment 2. [Figure 16] (A) and (B) are diagrams showing the execution status of forced descent control in Embodiment 3. [Figure 17] (A) and (B) are diagrams showing the execution status of forced descent control in Embodiment 4. [Figure 18] (A) and (B) are diagrams showing another example of the connection status of the power cable when connecting a dolly. [Figure 19] (A) and (B) are diagrams showing an example of the connection status of the air hose when connecting a dolly.

Mode for Carrying Out the Invention

[0009] <Embodiment 1> Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In the following description, the same or substantially the same configurations and elements are denoted by the same reference numerals, and repeated descriptions are omitted.

[0010] <Outline of Semi-Trailer> FIG. 1 is a view showing a semi-trailer 10 according to Embodiment 1. As shown in FIG. 1, the semi-trailer (trailer) 10 has a frame 11 and a box-shaped loading platform 12 mounted thereon. The frame 11 is provided with an axle (first axle) 13 having wheels 13a and an axle (second axle) 14 having wheels 14a. As will be described later, an axle lifting device 20 for raising and lowering the axle 13 is attached to the axle 13 located forward of the axle 14. Further, a kingpin 15, a wedge 16, and an auxiliary leg 17 are provided on the frame 11. The wedge 16 is disposed rearward of the kingpin 15, and the auxiliary leg 17 is disposed rearward of the wedge 16. Further, side guards 18 are provided at both ends in the vehicle width direction at the lower part of the box-shaped loading platform 12. Note that the front of the semi-trailer 10 shown in each drawing is the side to which a dolly 200 or a semi-tractor 300 described later is connected.

[0011] FIG. 2 is a view showing a connection process between a full tractor 150 and the semi-trailer 10, and FIG. 3 is a view showing a connection state between the full tractor 150 and the semi-trailer 10. Further, FIG. 4 is a view showing a connection process between a semi-tractor 300 and the semi-trailer 10, and FIG. 5 is a view showing a connection state between the semi-tractor 300 and the semi-trailer 10. As will be described later, the semi-trailer 10 can be connected not only to the full tractor 150 via a dolly 200 but also directly to the semi-tractor 300. That is, the semi-trailer 10 can be compatible with both the full tractor 150 and the semi-tractor 300. Note that the full tractor 150 is a tractor having a loading platform, and the semi-tractor 300 is a tractor not having a loading platform.

[0012] As shown in Figures 2 and 3, when the full tractor 150 tows the semi-trailer 10, the dolly 200 is connected to the full tractor 150, and the semi-trailer 10 is connected to the dolly 200, which is one of the connected components. In other words, the semi-trailer 10 is connected to the full tractor 150 via the dolly 200. A pintle hook 151 is provided at the rear end of the full tractor 150, and a lunette eye 201, which can be connected to the pintle hook 151, is provided at the front end of the dolly 200. The dolly 200 is also equipped with a coupler 202, also called a fifth-wheel coupler, via a turntable 208 with brakes. By engaging the kingpin 15 of the semi-trailer 10 with this coupler 202, the semi-trailer 10 can be connected to the dolly 200.

[0013] As shown in Figures 4 and 5, when the semi-tractor 300 tows the semi-trailer 10, the semi-trailer 10 is directly connected to the semi-tractor 300, which is one of the items to be connected. The semi-tractor 300 is equipped with a coupler 301, also called a fifth-wheel coupler. By engaging the kingpin 15 of the semi-trailer 10 with this coupler 301, it is possible to connect the semi-trailer 10 to the semi-tractor 300.

[0014] <Axle lifting device> The axle lifting device 20 mounted on the semi-trailer 10 will now be described. Figure 6 shows axles 13, 14 and their vicinity in range X6 of Figure 1. Although Figure 6 shows suspensions 30 and 40 located on the left side of the vehicle, the suspension located on the right side of the vehicle has a similar structure.

[0015] As shown in Figure 6, the suspension 30 supporting the rear axle 14 has a swing arm 32 attached to a bearing box 31 that supports the axle 14. An air bellows 33, which is an air spring, is provided between the end 32a of the swing arm 32 and the frame 11. A bracket 34 is fixed to the frame 11, and the end 32b of the swing arm 32 is rotatably connected to the bracket 34. Furthermore, the bracket 34 and the bearing box 31 are connected to each other via a shock absorber 35.

[0016] The suspension 40 supporting the front axle 13 has a swing arm 42 attached to a bearing box 41 that supports the axle 13. An air bellows 43, which is an air spring, is provided between the end 42a of the swing arm 42 and the frame 11. A bracket 44 is fixed to the frame 11, and the end 42b of the swing arm 42 is connected to the bracket 44 so as to be vertically movable. Furthermore, the bracket 44 and the bearing box 41 are connected to each other via a shock absorber 45.

[0017] As mentioned above, the axle 13, which is located in front of the axle 14, is provided with an axle lifting device 20 that moves the axle 13 up and down. The axle lifting device 20 has an actuator 21 attached to a bracket 44. Inside the housing 22 of the actuator 21 is a diaphragm (not shown) that is elastically deformed by air pressure. A push rod 23 is attached to the diaphragm, and the push rod 23 can be pushed out by supplying compressed air to the actuator 21.

[0018] A lever 24 is connected to the push rod 23, and the lever 24 is in contact with the end 42b of the swing arm 42. In other words, by supplying compressed air to the actuator 21, the push rod 23 can be pushed out and the lever 24 can be moved in the direction of arrow A1. This allows the lever 24 to raise the end 42b of the swing arm 42, and as shown in the enlarged section, the axle 13 can be moved from the lowered position B1 shown by the dashed line to the raised position B2 shown by the solid line. By moving the axle 13 to the raised position B2 in this way, the wheel 13a can be moved to a floating position away from the road surface S, as shown in Figure 6. On the other hand, by discharging compressed air from the actuator 21, the push rod 23 can be returned to the housing 22, and the axle 13 can be moved from the raised position B2 to the lowered position B1. By moving the axle 13 to the lowered position B1 in this way, the wheel 13a can be moved to a ground contact position where it is in contact with the road surface S.

[0019] Figure 7 shows an example of the control system 50 of the axle lifting device 20. As shown in Figure 7, the semi-trailer 10 is provided with an air tank 51 for storing compressed air, and compressed air is supplied to the air tank 51 from a compressor (not shown). The air tank 51 and a pair of left and right actuators 21 are connected to each other via a lifting valve 52, which is an electromagnetic switching valve. In other words, the lifting valve 52 has an input port 52a to which a pipe 53 extending from the air tank 51 is connected, and a pair of output ports 52b, 52c to which pipes 54, 55 extending from the pair of left and right actuators 21 are connected. The lifting valve 52 also has a pair of exhaust ports 52d, 52e for discharging compressed air to the outside.

[0020] The lift valve 52 can be operated in two states: an air supply state that supplies compressed air to the actuator 21, and an air discharge state that discharges compressed air from the actuator 21. By operating the lift valve 52 in the air supply state, the input port 52a and the output ports 52b and 52c can be connected to each other, and the exhaust ports 52d and 52e can be blocked. This allows the push rod 23 of the actuator 21 to be extended, moving the axle 13 to the raised position B2, and the wheel 13a to a floating position away from the road surface S. On the other hand, by operating the lift valve 52 in the air discharge state, the input port 52a can be blocked, the output port 52b and the exhaust port 52d can be connected to each other, and the output port 52c and the exhaust port 52e can be connected to each other. This allows the push rod 23 of the actuator 21 to be retracted, moving the axle 13 to the lowered position B1, and the wheel 13a to a ground-contact position in contact with the road surface S.

[0021] The control system 50 of the axle lifting device 20 has a control unit 56 consisting of a microcontroller, memory, and drive circuit. The control unit 56, which is an electronic control unit, determines the operating state of the lifting valve 52 based on signals from various sensors and outputs a control signal to the lifting valve 52. Sensors connected to the control unit 56 include an axle load sensor 57 that detects the load acting on the axle 13 and an axle load sensor 58 that detects the load acting on the axle 14. In addition, sensors connected to the control unit 56 include a proximity sensor 81 provided near the power socket 80 (described later) and a pressure sensor 77 provided in the wedge device 60 (described later).

[0022] For example, the control unit 56 activates the lift valve 52 to supply air when the load on the axles 13 and 14 detected by the axle load sensors 57 and 58 falls below a predetermined threshold. This allows the axle 13 to be moved to the raised position B2 when the load on the box-shaped cargo bed 12 (hereinafter referred to as cargo bed load) is small, and the wheels 13a can be lifted off the road surface S. On the other hand, with the wheels 13a in the lifted position, the control unit 56 activates the lift valve 52 to discharge air when the load acting on the axle 14 exceeds a predetermined threshold. This allows the axle 13 to be moved to the lowered position B1 when the load on the cargo bed is large, and the wheels 13a can be brought into contact with the road surface S.

[0023] <Wedge device> The wedge device 60 that drives the wedge 16 of the semi-trailer 10 will now be described. Figures 8(A) and 8(B) show the wedge device 60 within the range X8 shown in Figure 1. Figure 8(A) shows the wedge 16 moving to the protruding position, and Figure 8(B) shows the wedge 16 moving to the retracted position. Figure 9 shows the dolly 200 and semi-trailer 10 from the direction of arrow X9 in Figure 3, and Figure 10 shows an example of the control circuit 70 of the wedge device 60.

[0024] As shown in Figure 8(A), the wedge device 60 has a wedge 16 that is rotatably mounted on the frame 11 via a support pin 61. The wedge device 60 also has an air cylinder 63 positioned behind the wedge 16 and rotatably mounted on the frame 11 via a support pin 62. The piston rod 64 of the air cylinder 63 is connected to the end of the wedge 16. As shown in Figure 8(A), when the piston rod 64 of the air cylinder 63 is extended, the wedge 16 rotates in the direction of arrow C1 and moves to a protruding position where it protrudes from the lower surface of the frame. On the other hand, as shown in Figure 8(B), when the piston rod 64 of the air cylinder 63 is retracted, the wedge 16 rotates in the direction of arrow C2 and moves to a retracted position where it is stored within the frame.

[0025] As shown in the enlarged section of Figure 9, the turntable 208 of the dolly 200 is provided with a pair of guides 203 extending to the rear. With the kingpin 15 connected to the coupler 202 of the dolly 200, when the wedge 16 of the semi-trailer 10 is moved to the protruding position, the wedge 16 is inserted between the pair of guides 203, as shown in Figures 8(A) and 9. By inserting the wedge 16 of the semi-trailer 10 between the guides 203 provided on the dolly 200 in this way, relative rotation between the dolly 200 and the semi-trailer 10 can be suppressed. This prevents the so-called jackknife phenomenon of the semi-trailer 10. In the illustrated example, the guides 203 are provided on the turntable 208, but this is not the only option, and the guides 203 may be provided on the coupler 202. As shown in Figure 8(B), when the wedge 16 is moved to the retracted position, the wedge 16 is removed from between the guides 203.

[0026] As shown in Figure 10, the control circuit 70 of the wedge device 60 has a hand valve 71, which is a manually operated switching valve operated by an operator. The hand valve 71 has an input port 71a, an input / output port 71b, an input / output port 71c, and an exhaust port 71d. The hand valve 71 also has an operating lever 72 that controls the communication state of each port. A pipe 73 that communicates with the air tank 51 is connected to the input port 71a of the hand valve 71, and a pipe 74 that is vented to the atmosphere is connected to the exhaust port 71d of the hand valve 71. A pipe 75 that communicates with the retraction pressure chamber 65 of the air cylinder 63 is connected to the input / output port 71b of the hand valve 71, and a pipe 76 that communicates with the forward pressure chamber 66 of the air cylinder 63 is connected to the input / output port 71c of the hand valve 71. A normally closed type pressure sensor (detection unit) 77 is connected to the pipe (air pipe) 75 that communicates with the retraction pressure chamber 65 of the air cylinder 63.

[0027] When the operating lever 72 of the hand valve 71 is operated to the protruding position shown by the solid line, the input / output port 71b communicates with the exhaust port 71d, and the input / output port 71c connects to the input port 71a. In other words, compressed air is supplied to the forward pressure chamber 66 of the air cylinder 63, while air is discharged from the retraction pressure chamber 65 of the air cylinder 63. As a result, the piston rod 64 of the air cylinder 63 is extended in the direction of arrow D1, so that the wedge 16 can be moved to the protruding position. When the wedge 16 is moved to the protruding position in this way, the pressure in the retraction pressure chamber 65 of the air cylinder 63, i.e., the piping 75, decreases, so the pressure sensor 77 connected to the piping 75 turns ON and outputs an ON signal to the control unit 56.

[0028] On the other hand, when the operating lever 72 of the hand valve 71 is operated to the retracted position shown by the dashed line, the input / output port 71b communicates with the input port 71a, and the input / output port 71c connects to the exhaust port 71d. In other words, compressed air is supplied to the retracted pressure chamber 65 of the air cylinder 63, while air is discharged from the forward pressure chamber 66 of the air cylinder 63. As a result, the piston rod 64 of the air cylinder 63 is retracted in the direction of arrow D2, so that the wedge 16 can be moved to the retracted position. When the wedge 16 is moved to the retracted position in this way, the pressure in the retracted pressure chamber 65 of the air cylinder 63, i.e., the piping 75, increases, so the pressure sensor 77 connected to the piping 75 turns OFF and blocks the ON signal.

[0029] As mentioned above, when connecting the semi-trailer 10 to the dolly 200, the wedge 16 is moved to a protruding position, so that the wedge 16 is inserted between the guides 203 provided on the dolly 200. On the other hand, the semi-tractor 300 does not have a part equivalent to the guides 203. Therefore, as shown in Figure 5, when using the semi-trailer 10 connected to the semi-tractor 300, the wedge 16 of the semi-trailer 10 is stored in a retracted position. By storing the wedge 16 of the semi-trailer 10 in this way, the wedge 16 does not interfere with the frame or mudguards of the semi-tractor 300, so that the semi-trailer 10 can be connected to and used with semi-tractor 300 of various structures. In other words, by making the wedge 16 of the semi-trailer 10 retractable, the versatility of the semi-trailer 10 can be increased.

[0030] <Power cable connection> Next, the connection of the power cable 204 to the semi-trailer 10 will be explained. Figures 11(A) and (B) show the connection status of the power cable 204 when the dolly is attached. Figure 11(A) shows the connection process of the power cable 204, and Figure 11(B) shows the completed connection state of the power cable 204. Figures 12(A) and (B) show the connection status of the power cable 302 when the semi-tractor is attached. Figure 12(A) shows the connection process of the power cable 302, and Figure 12(B) shows the completed connection state of the power cable 302. Note that power cables 204 and 302 are power cables that supply power to safety lights such as stop lamps and turn signals, and are also called 7-pin cables.

[0031] As shown in Figures 2 and 3, when connecting a semi-trailer 10 to a full tractor 150 via a dolly 200, a power cable (supply path) 204 extending from the dolly 200 is connected to the power socket (connection part) 80 of the semi-trailer 10. In other words, the power plug 205 of the power cable 204 is connected to the power socket 80. The full tractor 150 and the dolly 200 are connected to each other via a power cable (not shown). In this way, by connecting the power plug 205 of the dolly 200 to the power socket 80 of the semi-trailer 10, the full tractor 150 and the semi-trailer 10 can be electrically connected. Here, as shown in the enlarged portion of Figure 2, the power plug 205 has a plug body 206 that is inserted into the power socket 80, and a metal detection plate 207 that extends radially from the cylindrical plug body 206.

[0032] As shown in Figure 11(A), the semi-trailer 10 has a power socket 80 and a normally open type proximity sensor (detection unit) 81 near the power socket 80. The proximity sensor 81 provided on the semi-trailer 10 turns ON when a metal object is present in the detection area X and outputs an ON signal to the control unit 56. On the other hand, the proximity sensor 81 turns OFF when no metal object is present in the detection area X and blocks the ON signal. The proximity sensor 81 is also called a proximity switch.

[0033] As shown by arrow E1 in Figure 11(A), the power plug 205 of the power cable 204 is moved toward the power socket 80 of the semi-trailer 10. Next, as shown in Figure 11(B), when the power plug 205 is connected to the power socket 80, the detection plate 207 is positioned in the detection area X of the proximity sensor 81. That is, when the semi-trailer 10 is connected to the dolly 200 and the power plug 205 of the dolly 200 is connected to the power socket 80 of the semi-trailer 10, an ON signal is output from the proximity sensor 81 to the control unit 56.

[0034] As shown in Figures 4 and 5, when connecting the semi-trailer 10 to the semi-tractor 300, the power plug 303 of the power cable 302 extending from the semi-tractor 300 is connected to the power socket 80 of the semi-trailer 10. In this way, the semi-tractor 300 and the semi-trailer 10 can be electrically connected by connecting the power plug 303 of the semi-tractor 300 to the power socket 80 of the semi-trailer 10. Here, as shown in the enlarged portion of Figure 4, the power plug 205 has a plug body 304 that is inserted into the power socket 80. In other words, the power plug 303 of the semi-tractor 300 does not have the aforementioned detection plate 207.

[0035] As shown by arrow E2 in Figure 12(A), when the power plug 303 of the power cable 302 is moved toward the power socket 80 of the semi-trailer 10, and as shown in Figure 12(B), when the power plug 303 is connected to the power socket 80, there is no metal object in the detection area X of the proximity sensor 81. In other words, when the semi-trailer 10 is connected to the semi-tractor 300, and the power plug 303 of the semi-tractor 300 is connected to the power socket 80 of the semi-trailer 10, the proximity sensor 81 is in the OFF state and blocks the ON signal.

[0036] <Forced descent control> Next, we will explain the forced lowering control of the axle 13 by the control unit 56 provided in the control system (control device) 50 of the axle lifting device 20. Figure 13 is a flowchart showing an example of the execution procedure for forced lowering control. Note that the forced lowering control shown in Figure 13 is a control performed by the control unit 56 at predetermined intervals. Figures 14(A) and (B) show the execution status of the forced lowering control.

[0037] As shown in Figure 13, in step S10, it is determined whether or not an ON signal is output from the proximity sensor 81 located near the power socket 80. As mentioned above, since the power plug 205 of the dolly 200 is provided with a detection plate 207, an ON signal is output from the proximity sensor 81 when the power plug 205 of the dolly 200 is connected to the power socket 80 of the semi-trailer 10. On the other hand, since the power plug 303 of the semi-tractor 300 is not provided with a detection plate 207, an ON signal is not output from the proximity sensor 81 when the power plug 303 of the semi-tractor 300 is connected to the power socket 80 of the semi-trailer 10.

[0038] In step S10, if it is determined that no ON signal is output from the proximity sensor 81, the process proceeds to step S20, where it is determined whether or not an ON signal is output from the pressure sensor 77 of the wedge device 60. As mentioned above, when connecting the semi-trailer 10 to the dolly 200, the wedge 16 is inserted between the guides 203 provided on the dolly 200. In other words, because the wedge 16 is moved to the protruding position, the pressure in the retraction pressure chamber 65 of the air cylinder 63, i.e., the piping 75, decreases, and an ON signal is output from the pressure sensor 77. On the other hand, when connecting the semi-trailer 10 to the semi-tractor 300, the wedge 16 is moved to the retracted position. In other words, because the pressure in the retraction pressure chamber 65 of the air cylinder 63, i.e., the piping 75, increases, an ON signal is not output from the pressure sensor 77.

[0039] In step S10 described above, if it is determined that an ON signal is output from the proximity sensor 81, it is determined that the dolly 200 is connected to the semi-trailer 10, and the process proceeds to step S30. Also, in step S20 described above, if it is determined that an ON signal is output from the pressure sensor 77, it is determined that the dolly 200 is connected to the semi-trailer 10, and the process proceeds to step S30. In other words, if an ON signal is output from at least one of the proximity sensor 81 and the pressure sensor 77, the control unit 56 determines that the object to be connected to the semi-trailer 10 is the dolly 200, and the process proceeds to step S30.

[0040] In step S30, the lifting valve 52 of the axle lifting device 20 is controlled to an air discharge state. As mentioned above, when the lifting valve 52 is controlled to an air discharge state, the push rod 23 of the actuator 21 retracts, moving the axle 13 to the lowered position B1, and the wheel 13a moves to the ground contact position where it contacts the road surface S. In other words, as shown in Figure 14(A), because the load acting on the axles 13 and 14 is small and the load on the cargo bed is small, even if the wheel 13a had moved to the floating position, if it is determined that the object to be connected is the dolly 200, the axle 13 is lowered to the lowered position B1 and the wheel 13a moves to the ground contact position, as shown in Figure 14(B).

[0041] In other words, when the semi-trailer 10 is connected to the full tractor 150 via a dolly 200, regardless of the axle load of the axles 13 and 14, i.e., the load on the cargo bed, the axle 13 is lowered to the lowered position and the wheel 13a is moved to the ground contact position. This allows the axle center of the semi-trailer 10 to be moved from "Ca1" to the forward "Ca2", and the distance between the kingpin center Ck and the axle centers Ca1 and Ca2 can be reduced from "La1" to "La2". By reducing the axle distance La2 of the semi-trailer 10 in this way, the difference in inner wheel clearance of the semi-trailer 10 can be reduced, making it easier to operate when connected to the dolly. Note that when wheel 13a is lifted and only wheel 14a is in contact with the ground, the axle center Ca1 is the center of the axle 14 in the vehicle width direction. Also, when both wheels 13a and 14a are in contact with the ground, the axle center Ca2 is the center of the axles 13 and 14 in the longitudinal direction and the center in the vehicle width direction.

[0042] In the above explanation, the control unit 56 determines that the semi-trailer 10 is coupled to a dolly 200 when an ON signal is output from at least one of the proximity sensor 81 and the pressure sensor 77, but this is not the only way. For example, when determining whether the coupled object is a dolly 200, only the proximity sensor 81 may be used without the pressure sensor 77, or only the pressure sensor 77 may be used without the proximity sensor 81. Also, in the above explanation, when it is determined that the coupled object is a dolly 200, the axle 13 is lowered from the raised position B2 to the lowered position B1, but it goes without saying that if the axle 13 has already been lowered to the lowered position B1, the axle 13 will be held in the lowered position B1. In other words, when the control unit 56 determines that the coupled object is a dolly 200, it controls the actuator 21 to place the axle 13 in the lowered position B1.

[0043] <Embodiment 2> Although the above description illustrates a semi-trailer 10 having two axles 13 and 14, the present invention is not limited to this and may be applied to a semi-trailer 100 having three or more axles. Figures 15(A) to (D) show the execution status of forced lowering control in Embodiment 2.

[0044] As shown in Figure 15(A), the semi-trailer (trailer) 100 according to Embodiment 2 has three axles 101, 102, and 103. Axle 101 is located in front of axle 102, and axle 102 is located in front of axle 103. Axle 101 is provided with a wheel 101a, axle 102 is provided with a wheel 102a, and axle 103 is provided with a wheel 103a. Furthermore, axle 101 and 102 are provided with axle lifting devices 20, but axle 103 is not provided with an axle lifting device 20.

[0045] When the semi-trailer 100 determines that the object to be connected is a dolly 200, it lowers the axle 102 to the lowered position and moves the wheel 102a to the ground position, as shown in Figure 15(B). This moves the axle center of the semi-trailer 100 from "Cb1" to the forward "Cb2," and reduces the distance between the kingpin center Ck and the axle centers Ca1 and Ca2 from "Lb1" to "Lb2." By reducing the axle distance Lb2 of the semi-trailer 100 in this way, the inner wheel difference of the semi-trailer 100 can be reduced, making it easier to operate when connected to a dolly. In this case, axle 102 functions as the first axle and axle 103 functions as the second axle.

[0046] The example shown in Figure 15(B) is not the only one; if it is determined that the object to be connected is a dolly 200, the axle 101 may be lowered to the lowered position. In other words, as shown in Figure 15(C), if it is determined that the object to be connected to the semi-trailer 100 is a dolly 200, the axle 101 may be lowered to the lowered position and the wheel 101a may be moved to the ground position. This allows the axle center of the semi-trailer 100 to be moved from "Cb1" to the forward "Cb3", and the distance between the kingpin center Ck and the axle centers Ca1, Ca3 can be reduced from "Lb1" to "Lb3". By reducing the axle distance Lb3 of the semi-trailer 100 in this way, the inner wheel difference of the semi-trailer 100 can be reduced, making it easier to operate when connected to a dolly. In this case, axle 101 functions as the first axle and axle 103 functions as the second axle.

[0047] The examples shown in Figures 15(B) and (C) are not the only ones; if it is determined that the object to be connected is a dolly 200, both axles 101 and 102 may be lowered to the lowered position. In other words, as shown in Figure 15(D), if it is determined that the object to be connected to the semi-trailer 100 is a dolly 200, the axles 101 and 102 may be lowered to the lowered position and the wheels 101a and 102a may be moved to the ground contact position. This allows the axle center of the semi-trailer 100 to be moved from "Cb1" to the forward "Cb4", and the distance between the kingpin center Ck and the axle centers Ca1 and Ca4 can be reduced from "Lb1" to "Lb4". By reducing the axle distance Lb4 of the semi-trailer 100 in this way, the inner wheel difference of the semi-trailer 100 can be reduced, making it easier to operate when connected to a dolly. In this case, at least one of axle 101 and axle 102 functions as the first axle, and axle 103 functions as the second axle.

[0048] <Embodiments 3, 4> Next, embodiments 3 and 4 will be described. Figures 16(A) and (B) show the execution status of forced descent control in embodiment 3. Figures 17(A) and (B) show the execution status of forced descent control in embodiment 4.

[0049] As shown in Figure 16(A), the semi-trailer (trailer) 110 according to Embodiment 3 has three axles 111, 112, and 113. Axle 111 is located in front of axle 112, and axle 112 is located in front of axle 113. Axle 111 is provided with a wheel 111a, axle 112 is provided with a wheel 112a, and axle 113 is provided with a wheel 113a. Furthermore, axle 111 and 113 are provided with axle lifting devices 20, while axle 112 is not provided with an axle lifting device 20.

[0050] When the semi-trailer 110 determines that the object to be connected is a dolly 200, it lowers the axle 111 to the lowered position and moves the wheel 111a to the ground position, as shown in Figure 16(B). This moves the axle center of the semi-trailer 110 from "Cc1" to the forward "Cc2," and reduces the distance between the kingpin center Ck and the axle centers Cc1 and Cc2 from "Lc1" to "Lc2." By reducing the axle distance Lc2 of the semi-trailer 110 in this way, the inner wheel difference of the semi-trailer 110 can be reduced, making it easier to operate when connected to a dolly. In this case, axle 111 functions as the first axle and axle 112 functions as the second axle.

[0051] As shown in Figure 17(A), the semi-trailer (trailer) 120 according to Embodiment 4 has three axles 121, 122, and 123. Axle 121 is located in front of axle 122, and axle 122 is located in front of axle 123. Axle 121 is provided with a wheel 121a, axle 122 is provided with a wheel 122a, and axle 123 is provided with a wheel 123a. Furthermore, axle 121 is provided with an axle lifting device 20, while axles 122 and 123 are not provided with an axle lifting device 20.

[0052] When the semi-trailer 120 determines that the object to be connected is a dolly 200, it lowers the axle 121 to the lowered position and moves the wheel 121a to the ground position, as shown in Figure 17(B). This moves the axle center of the semi-trailer 120 from "Cd1" to the forward "Cd2," and reduces the distance between the kingpin center Ck and the axle centers Cd1 and Cd2 from "Ld1" to "Ld2." By reducing the axle distance Ld2 of the semi-trailer 120 in this way, the inner wheel difference of the semi-trailer 120 can be reduced, making it easier to operate when connected to a dolly. In this case, axle 121 functions as the first axle, and at least one of axle 122 and axle 123 functions as the second axle.

[0053] <Embodiment 5> In the above description, a proximity sensor 81 is provided near the power socket 80 as a detection unit to detect that the object to be connected is the dolly 200. However, it is not limited to non-contact sensors such as the proximity sensor 81, and a limit switch may also be provided near the power socket 80. Here, Figures 18(A) and (B) show other examples of the connection status of the power cable 204 when the dolly is connected. Figure 18(A) shows the connection process of the power cable 204, and Figure 18(B) shows the completed connection state of the power cable 204.

[0054] As shown in Figure 18(A), the semi-trailer 10 has a power socket 80 and a normally open type limit switch (detection unit, contact switch) 82 near the power socket 80. The limit switch 82 has a microswitch 83 and a plunger 84 opposite it. When the microswitch 83 is pressed in via the plunger 84, the limit switch 82 turns ON and outputs an ON signal to the control unit 56. On the other hand, when the plunger 84 is released and the microswitch 83 is released, the limit switch 82 turns OFF and blocks the ON signal.

[0055] As shown by arrow E1 in Figure 18(A), the power plug 205 of the power cable 204 is moved toward the power socket 80 of the semi-trailer 10. Next, as shown in Figure 18(B), when the power plug 205 is connected to the power socket 80, the plunger 84 of the limit switch 82 is pushed in by the detection plate 207. That is, when the semi-trailer 10 is connected to the dolly 200 and the power plug 205 of the dolly 200 is connected to the power socket 80 of the semi-trailer 10, an ON signal is output from the limit switch 82 to the control unit 56. In this way, even when the limit switch 82 is used instead of the proximity sensor 81, the control unit 56 can determine that the object to be connected is the dolly 200.

[0056] <Embodiment 6> In the above description, a detection plate 207 is provided on the power plug 205 of the power cable 204 extending from the dolly 200, but this is not the only option, and a detection plate may also be provided on the air coupler of the air hose extending from the dolly 200. As shown in Figures 2 and 3, when connecting the semi-trailer 10 to the full tractor 150 via the dolly 200, the air hose (supply path) 210 extending from the dolly 200 is connected to the air coupler (connection part) 90 of the semi-trailer 10. In other words, the air coupler 211 of the air hose 210 is connected to the air coupler 90. The full tractor 150 and the dolly 200 are connected to each other via an air hose (not shown). By connecting the air coupler 211 of the dolly 200 to the air coupler 90 of the semi-trailer 10 in this way, compressed air can be supplied from the full tractor 150 to the semi-trailer 10.

[0057] Figures 19(A) and (B) show examples of the connection status of the air hose 210 when the dolly is attached. Figure 19(A) shows the process of connecting the air hose 210, and Figure 19(B) shows the completed state of the connection of the air hose 210. As shown in Figure 19(A), the semi-trailer 10 has an air coupler 90 and a proximity sensor 81 near the air coupler 90. The air coupler 211 of the dolly 200 has a coupler body 212 that is connected to the air coupler 90 of the semi-trailer 10, and a metal detection plate 213 that extends from the coupler body 212.

[0058] As shown by arrow E3 in Figure 19(A), the air coupler 211 of the dolly 200 is moved toward the air coupler 90 of the semi-trailer 10. Next, as shown by arrow E4 in Figure 19(B), when the air coupler 211 is rotated and connected to the air coupler 90, the detection plate 213 is positioned in the detection area X of the proximity sensor 81. That is, when the semi-trailer 10 is connected to the dolly 200 and the air coupler 211 of the dolly 200 is connected to the air coupler 90 of the semi-trailer 10, an ON signal is output from the proximity sensor 81 to the control unit 56. In this way, even when the proximity sensor 81 is located near the air coupler 90, the control unit 56 can determine that the object to be connected is the dolly 200.

[0059] In the examples shown in Figures 19(A) and (B), a proximity sensor 81 is provided near the air coupler 90 as a detection unit to detect that the object to be connected is the dolly 200. However, the system is not limited to this, and the aforementioned limit switch 82 may also be provided near the air coupler 90. In other words, even if a limit switch 82 is used instead of the proximity sensor 81, the control unit 56 can still determine that the object to be connected is the dolly 200.

[0060] The present invention is not limited to the embodiments described above, and it goes without saying that various modifications are possible without departing from the spirit of the invention. For example, as sensors for detecting the detection plates 207 and 213 of the power plug 205 and air coupler 211, magnetic or high-frequency oscillation type proximity sensors that utilize a magnetic field may be used, or capacitive type proximity sensors that utilize an electric field may be used. Also, although normally open type proximity sensors 81 and limit switches 82 are used in the above description, the invention is not limited to these, and normally closed type proximity sensors and limit switches may be used. Also, although limit switches equipped with plungers 84 are used as limit switches for detecting the detection plates 207 and 213 of the power plug 205 and air coupler 211 in the above description, the invention is not limited to these, and limit switches equipped with levers, rollers, etc., may be used. Also, although the detection plates 207 and 213 shown are metal plates, the invention is not limited to these, and materials other than metal may be used for the detection plates 207 and 213. Furthermore, although the above description mentions that detection plates 207 and 213 are provided on the power plug 205 and air coupler 211, the explanation is not limited to this, and other protrusions or the like may be provided on the power plug 205 and air coupler 211.

[0061] In the examples shown in Figures 11, 12, 18, and 19, the proximity sensor 81 and limit switch 82 are provided on the mounting bracket of the power socket 90, but the system is not limited to this, and the proximity sensor 81 and limit switch 82 may be provided on other parts. Also, in the example shown in Figure 19, the proximity sensor 81 is provided on the mounting bracket of the air coupler 90, but the system is not limited to this, and the proximity sensor 81 may be provided on other parts. Furthermore, in the above description, the power cable 204 that supplies power to the lights and the air hose 210 that supplies compressed air to the brake chamber, etc., are given as supply routes extending from the dolly 200, but the system is not limited to these. For example, the power cable for the ABS (Anti-lock Brake System) or the power cable for the auxiliary leg 17 may be used as the supply route extending from the dolly 200.

[0062] In the above description, a normally closed type pressure sensor 77 is connected to the piping 75 to detect the protruding position of the wedge 16, but this is not the only option. For example, a normally open type pressure sensor may be connected to the piping 76. Also, the sensor used to detect whether the wedge 16 is in the protruding position is not limited to the pressure sensor 77 provided in the control circuit 70. For example, the position of the wedge 16 may be detected using a non-contact sensor such as a proximity sensor, or a contact switch such as a limit switch. Furthermore, in the example shown in Figure 8, the wedge 16 is moved to the protruding position by extending the piston rod 64, and to the retracted position by retracting the piston rod 64, but this structure is not the only option. For example, the structure may be such that the wedge 16 is moved to the retracted position by extending the piston rod 64, and to the protruding position by retracting the piston rod 64. In addition, the wedge 16 shown is a rotating wedge, but this is not the only option; it may also be a linear wedge that protrudes downward.

[0063] In the above description, an actuator equipped with a diaphragm is used as the actuator 21 for raising and lowering the axles 13, 14, etc., but it is not limited to this, and an actuator consisting of an air cylinder or a hydraulic cylinder may be used, or an actuator consisting of an electric motor may be used. Also, in the above description, a semi-tractor 300 is given as an example of a vehicle to be coupled to the semi-trailer 10 in addition to the dolly 200, but it is not limited to this, and other vehicles equipped with a coupler may be used as a coupling target. The semi-trailers 10, 100, 110, and 120 shown are van trailers, but it is not limited to these. Trailers to which the present invention is applied may be, for example, flatbed trailers, container trailers, bulk trailers, tank trailers, vehicle transport trailers, low-bed trailers, or dump trailers. [Explanation of symbols]

[0064] 10 Semi-trailer (trailer) 13 axles (first axle) 14 axles (2nd axle) 16 Wedge 21 Actuators 50 Control Systems (Control Devices) 63 Air Cylinder 75 Piping (Air Piping) 77 Pressure sensor (detection unit) 80 Power socket (connection part) 81 Proximity sensor (detection unit) 82. Limit switch (detection unit, contact switch) 90 Air coupler (connection part) 100 Semi-trailer (trailer) 101 Axle (First Axle) 102 Axle (First Axle) 103 Axle (2nd axle) 110 Semi-trailer (trailer) 111 Axle (First Axle) 112 Axle (2nd axle) 120 Semi-trailer (trailer) 121 Axle (First Axle) 122 Axle (2nd axle) 123 Axle (2nd axle) 200 Dolly (for linking) 203 Guide 204 Power cable (supply path) 210 Air hose (supply route) 300 Semi-tractor (for coupling)

Claims

1. A trailer that is used in conjunction with a dolly, which is one of the components to be connected, and is equipped with a first axle and a second axle, An actuator is provided on the first axle, which is located in front of the second axle, and moves the first axle between an elevated position and a lowered position. A control device comprising a detection unit for detecting that the object to be connected is the dolly, and which controls the actuator to position the first axle in the lowered position when the object to be connected is the dolly, A trailer equipped with [a certain feature].

2. In the trailer according to claim 1, The control device, when the object to be connected is the dolly, positions the first axle in the lowered position regardless of the load capacity of the cargo bed. Trailer.

3. In the trailer according to claim 1, It has a connection part to which a supply path extending from the dolly is connected, The detection unit is a proximity sensor or contact switch provided near the connection unit. Trailer.

4. In the trailer according to claim 1, A wedge that moves between a protruding position inserted between a pair of guides provided by the dolly and a retracted position withdrawn from between the pair of guides, An air cylinder attached to the wedge moves the wedge between the protruding position and the retracted position, It has, The detection unit is a pressure sensor connected to the air piping of the air cylinder. Trailer.

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