Towed vehicle and towing system

Abstract

To provide a towed vehicle which enables reduction of a possibility of slipping through an inclined plane, and to provide a towing system.SOLUTION: A towed vehicle 1 includes: front wheels 31 (wheels); a front axle 32 (an axle) extending in a vehicle width direction D2 (one direction); and a brake mechanism 4 for applying a brake force to the front axle 32. The brake mechanism 4 has: a support shaft 41 provided at a position spaced apart from the front axle 32; and a brake part 5 supported by the support shaft 41 rotatably around the vehicle width direction D2. The brake part 5 rotates around the vehicle width direction D2 relative to the support shaft 41 so as to transition between a brake state and a release state. The brake part 5 includes: a first arm part 52 extending from the support shaft 41 toward an upper part of the front axle 32; a brake member 53 provided at the first arm part 52 to apply a brake force to the front axle 32; and an inclined part 54 inclined toward the front axle 32 when an angle of a vehicle body of the towed vehicle 1 relative to a horizontal surface becomes a predetermined angle or larger.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a towed vehicle and a towing system.

Background Art

[0002] As a technique related to a towing system for towing a towed vehicle using a towing vehicle, a coupling device described in Patent Document 1 is known. This coupling device includes an inner cylinder provided on the hook side as a coupler coupled to the towing vehicle, and an outer cylinder connected to the towed vehicle side. When braking is applied while the towing vehicle is towing the towed vehicle, the towed vehicle moves forward relative to the towing vehicle due to inertial force, and relative movement occurs between the inner cylinder and the outer cylinder. At this time, one end of the lever is pushed by the inner cylinder, so that the lever rotates clockwise, and the cable connected to the other end of the lever is pulled. As a result, the braking device of the towed vehicle connected to the cable operates.

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 towed vehicle with a towing vehicle, it has been conventionally required to operate the brakes of not only the towing vehicle but also the towed vehicle to ensure sufficient braking force. Particularly on a slope, if only the brakes of the towing vehicle are operated, the weight of the towed vehicle will be supported only by the braking force of the towing vehicle, and the braking force may be insufficient. As a result, there is a possibility that the towing vehicle and the towed vehicle may slide down the slope.

[0005] An object of the present disclosure is to provide a towed vehicle and a towing system capable of reducing the possibility of sliding down on a slope.

Means for Solving the Problems

[0006] A towed vehicle according to one aspect of the present disclosure is a towed vehicle towed by a towing vehicle, and includes a pair of wheels, an axle extending in one direction and having the pair of wheels attached thereto, and a braking mechanism that applies a braking force to the axle, the braking mechanism being provided at a position spaced apart from the axle in a direction intersecting the one direction, the braking mechanism having a support shaft extending in one direction, and a braking unit supported by the support shaft so as to be rotatable around the one direction, and the braking unit rotating around the support shaft in one direction provides a braking state in which a braking force is applied to the axle and a braking state in which application of the braking force to the axle is released. The braking unit is capable of transitioning between a released state in which the brake is engaged and a released state in which the brake is engaged, and the braking unit comprises a first arm portion extending from the support axle upward toward the axle, a braking member provided on the first arm portion opposite the support axle for applying a braking force to the axle, and an inclined portion extending from the support axle upward beyond the support axle and inclining toward the axle when the angle of the body of the towed vehicle relative to the horizontal plane becomes equal to or greater than a predetermined angle, and in the released state the braking member is separated from the axle, and in the braking state the braking member comes into contact with the axle to apply a braking force to the axle.

[0007] In this towed vehicle, in the released state, the braking member provided on the side of the first arm portion opposite the support shaft is separated from the axle, so that no braking force is applied to the axle by the braking member. For example, when the towed vehicle travels on a slope and the angle of the body of the towed vehicle with respect to the horizontal plane becomes equal to or greater than a predetermined angle, the braking portion rotates in one direction about the support shaft so that the inclined portion tilts toward the axle. As a result, the towed vehicle transitions from the released state to the braked state, and the braking member comes into contact with the axle, applying a braking force to the axle. Therefore, since a braking force can be applied to the axle of the towed vehicle on a slope, the possibility of the vehicle sliding down the slope can be reduced.

[0008] The inclined portion may extend from the support shaft upward beyond the support shaft, and may have a second arm portion different from the first arm portion, and a mass body provided on the second arm portion opposite the support shaft, and in the released state, the second arm portion may form a predetermined angle with respect to the vertical direction. In this case, in the braking state, the braking member comes into contact with the axle, and the braking member is pressed against the axle by the weight of the mass body provided on the second arm portion opposite the support shaft. This makes it easier to ensure the braking force applied to the axle.

[0009] The angle that the second arm unit makes with respect to the vertical direction in the released state may be changeable. In this case, by adjusting the angle that the second arm unit makes with respect to the vertical direction in the released state, the angle of the vehicle body at which the towed vehicle transitions from the released state to the braking state can be adjusted. Therefore, a braking force can be applied to the towed vehicle on a slope with a desired gradient.

[0010] The mass body may have a housing section and a swinging body housed in the housing section and swingable within the housing section. In this case, when the towed vehicle transitions from the released state to the braking state and the braking section rotates so that the mass body approaches the axle, the swinging body swings within the housing section so as to approach the axle. This allows the center of gravity of the mass body in the braking state to be closer to the axle than, for example, when the mass body does not have a swinging body. As a result, the weight of the mass body can press the braking member against the axle more strongly, thereby applying a greater braking force to the axle.

[0011] The braking member has a contact surface that contacts the axle, and the contact surface may have a shape corresponding to the shape of the outer surface of the axle. In this case, a large contact area between the contact surface of the braking member and the outer surface of the axle in the braking state can be ensured. This makes it easier to ensure the braking force applied to the axle.

[0012] A towing system according to an aspect of the present disclosure includes the towed vehicle described above and a towing vehicle that tows the towed vehicle. The towing system provides the same effects as those provided by the towed vehicle described above. Effect of the Invention

[0013] According to the present disclosure, the possibility of slipping down a slope can be reduced. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram illustrating a traction system according to an embodiment. [Diagram 2] FIG. 2 is a schematic perspective view showing the underbody structure of the towed vehicle shown in FIG. [Diagram 3] FIG. 4 is a schematic cross-sectional view showing a towed vehicle in a released state. [Figure 4] FIG. 2 is a schematic cross-sectional view showing a towed vehicle in a braking state. [Diagram 5] 1A is a schematic diagram showing a towing system according to a comparative example, and FIG. 1B is a schematic diagram showing a towing system according to the present embodiment. [Figure 6] 1A is a cross-sectional view showing the inclined portion according to the modified example in a released state, and FIG. 1B is a cross-sectional view showing the inclined portion according to the modified example in a braking state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In this specification, a clockwise direction based on the viewpoint of a reference drawing may be referred to as a "rotation direction" and a counterclockwise direction may be referred to as a "counter-rotation direction."

[0016] FIG. 1 is a schematic diagram showing a towing system 10 according to an embodiment. The towing system 10 is used, for example, in a factory. The towing system 10 transports, for example, luggage. The towing system 10 travels not only on a horizontal plane but also on a slope inclined with respect to the horizontal plane. The towing system 10 travels on a slope, for example, when traveling through an underpass or when moving to a different floor. The towing system 10 includes a towed vehicle 1, a towing vehicle 20, and a coupler 30.

[0017] The towed vehicle 1 is a vehicle towed by a towing vehicle 20. The towed vehicle 1 is, for example, a dolly. The towed vehicle 1 is loaded with cargo to be transported by the towing system 10, for example.

[0018] The towing system 10 may include multiple towed vehicles 1. In this embodiment, the towing system 10 includes two towed vehicles 1. However, the number of towed vehicles 1 is not particularly limited. The two towed vehicles 1 are arranged in the fore-and-aft direction D1 of the towed vehicle 1. The fore-and-aft direction D1 is a direction along a relative coordinate set for the towed vehicle 1. The two towed vehicles 1 are connected to each other. Of the two towed vehicles 1, the front one is connected to the towing vehicle 20. Details of the towed vehicle 1 will be described later.

[0019] The towing vehicle 20 is a vehicle that tows the towed vehicle 1. The towing vehicle 20 may be, for example, a towing tractor. The type of the towing vehicle 20 is not particularly limited. In the following description, the towing vehicle 20 and each of the multiple towed vehicles 1 may be simply referred to as a "vehicle."

[0020] The couplers 30 couple the vehicles together. In this embodiment, the towing system 10 includes the same number of couplers 30 as the towed vehicles 1. One coupler 30 couples the towing vehicle 20 and the above-mentioned front towed vehicle 1. Another coupler 30 couples two towed vehicles 1 arranged side by side in the fore-and-aft direction D1. In this embodiment, the couplers 30 cannot be extended or retracted in the fore-and-aft direction D1. When the towing vehicle 20 and the towed vehicle 1 are traveling or stopped, the distance between the vehicles is kept approximately constant.

[0021] Fig. 2 is a schematic perspective view showing the vehicle body underbody structure of the towed vehicle 1 shown in Fig. 1. The towed vehicle 1 includes a frame 2. As an example, a loading platform on which luggage is placed is supported on the frame 2. The frame 2 has side frames 21 and cross members 22. In this embodiment, the frame 2 has a pair of side frames 21 and three cross members 22. However, the configuration of the frame 2 is not particularly limited.

[0022] The pair of side frames 21 extend in the front-rear direction D1 of the towed vehicle 1. The pair of side frames 21 are spaced apart from each other in a vehicle width direction D2 (one direction) of the towed vehicle 1 that intersects (e.g., perpendicular to) the front-rear direction D1. The vehicle width direction D2 is a direction along relative coordinates set for the towed vehicle 1. The cross member 22 extends in the vehicle width direction D2 of the towed vehicle 1 between the pair of side frames 21. The cross member 22 connects the pair of side frames 21 together.

[0023] The three cross members 22 include a front cross member 23, an end cross member 24, and a central cross member 25. The front cross member 23 connects the front ends of the pair of side frames 21 to each other. A coupler 30 is fixed to the front cross member 23. The end cross member 24 connects the rear ends of the pair of side frames 21 to each other. The central cross member 25 is located between the front cross member 23 and the end cross member 24 in the front-rear direction D1 of the towed vehicle 1.

[0024] The towed vehicle 1 further includes a pair of front wheels 31 (wheels), a front wheel axle 32 (axle), and a front wheel axle support 33. The pair of front wheels 31 are disposed on the left and right sides of the frame 2 in the front portion of the frame 2. The front wheel axle 32 extends in the vehicle width direction D2 of the towed vehicle 1. In this embodiment, the length of the front wheel axle 32 in the vehicle width direction D2 is longer than the distance between the pair of side frames 21. The pair of front wheels 31 are attached to the front wheel axle 32. The front wheel axle 32 is cylindrical. The front wheel axle 32 has an outer surface 32a that is circular when viewed from the vehicle width direction D2.

[0025] The front wheel axle support parts 33 support the front wheel axle 32 rotatably around the vehicle width direction D2. In this embodiment, the towed vehicle 1 is equipped with a pair of front wheel axle support parts 33. The pair of front wheel axle support parts 33 respectively protrude downward from the pair of side frames 21. The front wheel axle support parts 33 support both ends of the front wheel axle 32 in the vehicle width direction D2.

[0026] The towed vehicle 1 further includes a pair of rear wheels 34, a rear wheel axle 35, and a rear wheel axle support portion 36. The pair of rear wheels 34 are respectively arranged on the left and right sides of the frame 2 at the rear portion of the frame 2. The rear wheel axle 35 extends in the vehicle width direction D2 of the towed vehicle 1. A pair of rear wheels 34 are attached to the rear wheel axle 35. In the present embodiment, the rear wheel axle 35 is longer than the separation width of the pair of side frames 21. The rear wheel axle 35 is spaced apart from the front wheel axle 32 in the front-rear direction D1. The rear wheel axle 35 has a cylindrical shape. The rear wheel axle 35 has an outer surface 35a that is circular when viewed from the vehicle width direction D2.

[0027] The rear wheel axle support portion 36 rotatably supports the rear wheel axle 35 around the vehicle width direction D2. The rear wheel axle support portion 36 is spaced apart from the front wheel axle support portion 33 in the front-rear direction D1. In the present embodiment, the towed vehicle 1 includes a pair of rear wheel axle support portions 36. The pair of rear wheel axle support portions 36 respectively project downward from the pair of side frames 21. The rear wheel axle support portion 36 supports both end portions of the rear wheel axle 35 in the vehicle width direction D2.

[0028] The towed vehicle 1 further includes a braking mechanism 4. The braking mechanism 4 applies a braking force to the front wheel axle 32. When the braking mechanism 4 applies a braking force to the front wheel axle 32, the towed vehicle 1 decelerates or stops. The towed vehicle 1 can mutually transition between a braking state in which a braking force is applied to the front wheel axle 32 and a released state in which the application of the braking force to the front wheel axle 32 is released.

[0029] In the present embodiment, when the towed vehicle 1 travels on an inclined plane having a gradient of a predetermined value or more and the angle of the vehicle body of the towed vehicle 1 with respect to the horizontal plane becomes a predetermined angle or more, the towed vehicle 1 enters a braking state. The angle of the vehicle body of the towed vehicle 1 with respect to the horizontal plane means, for example, the angle of the straight line connecting the front wheel axle 32 and the rear wheel axle 35 with respect to the horizontal plane. When the towed vehicle 1 travels on an inclined plane having a gradient less than a predetermined value or on a horizontal plane and the angle of the vehicle body of the towed vehicle 1 with respect to the horizontal plane becomes less than a predetermined angle, the towed vehicle 1 enters a released state.

[0030] The braking mechanism 4 is provided under the body of the towed vehicle 1. The braking mechanism 4 is provided between the front wheel axle 32 and the rear wheel axle 35 in the front-rear direction D1. The braking mechanism 4 has a support shaft 41, a support shaft support portion 42, and a braking portion 5.

[0031] The support shaft 41 extends in the vehicle width direction D2. The length of the support shaft 41 in the vehicle width direction D2 is longer than the separation width of the pair of side frames 21. The support shaft 41 is provided at a position separated from the front wheel axle 32 in a direction intersecting the vehicle width direction D2. In this embodiment, the support shaft 41 is provided above and rearward of the front wheel axle 32. For example, the distance from the support shaft 41 to the front wheel axle 32 in the front-rear direction D1 is shorter than the distance from the front wheel axle 32 to the central cross member 25 in the front-rear direction D1. The distance from the support shaft 41 to the front wheel axle 32 is, for example, 50 mm or more and 500 mm or less (200 mm as an example). The support shaft 41 is provided between the front wheel axle 32 and the rear wheel axle 35 in the front-rear direction D1.

[0032] The support shaft support portion 42 supports the support shaft 41. In this embodiment, the support shaft support portion 42 fixes the support shaft 41 so that it cannot rotate. In this embodiment, the towed vehicle 1 is equipped with a pair of support shaft support portions 42. The pair of support shaft support portions 42 each protrude downward from the pair of side frames 21. The pair of support shaft support portions 42 support both ends of the support shaft 41 in the vehicle width direction D2. The support shaft support portion 42 is provided between the front wheel axle support portion 33 and the rear wheel axle support portion 36 in the front-rear direction D1.

[0033] The braking unit 5 is supported by the support shaft 41 so as to be rotatable around the vehicle width direction D2. In this embodiment, the braking unit 5 is disposed between the pair of side frames 21 in the vehicle width direction D2. The braking unit 5 is disposed between the front cross member 23 and the central cross member 25 in the front-rear direction D1. The braking unit 5 rotates around the support shaft 41 around the vehicle width direction D2, thereby enabling the towed vehicle 1 to transition between a braked state and a released state.

[0034] FIG. 3 is a schematic cross-sectional view showing the towed vehicle 1 in the released state. FIG. 3 is a cross-sectional view of the towed vehicle 1 cut at a section perpendicular to the vehicle width direction D2. In FIG. 3, the support shaft support portion 42 is omitted. In the example of FIG. 3, the towed vehicle 1 is located on a horizontal plane H, and the angle of the body of the towed vehicle 1 with respect to the horizontal plane H is less than a predetermined angle (0°). As shown in FIG. 3, the braking portion 5 is L-shaped overall. The braking portion 5 has a base portion 51, a first arm portion 52, a braking member 53, and an inclined portion 54.

[0035] The base portion 51 forms a base of the braking portion 5. In this embodiment, the base portion 51 has a cylindrical shape. The support shaft 41 is inserted into the cylindrical base portion 51. The base portion 51 is supported by the support shaft 41 so as to be rotatable around the vehicle width direction D2.

[0036] The first arm portion 52 extends from the support shaft 41 toward above the front wheel axle 32. In this embodiment, the first arm portion 52 extends from the outer circumferential surface of the base portion 51 toward above the front wheel axle 32. The first arm portion 52 has a rectangular parallelepiped shape (see FIG. 2).

[0037] The braking member 53 is a member for applying a braking force to the front wheel set 32. In this embodiment, the braking member 53 is provided at the end of the first arm portion 52 opposite the support shaft 41. In the released state, the braking member 53 is separated from the front wheel set 32. In the released state, the braking member 53 faces the front wheel set 32 ​​in the vertical direction D3. The vertical direction D3 is a direction along a relative coordinate set for the towed vehicle 1.

[0038] The braking member 53 has a fan shape. As described later, in a braking state, the braking member 53 comes into contact with the front wheel axle 32. The braking member 53 has a contact surface 53a that comes into contact with the front wheel axle 32. The contact surface 53a has a shape corresponding to the shape of the outer surface 32a of the front wheel axle 32. As described above, the front wheel axle 32 has a cylindrical shape, so in this embodiment, the shape of the contact surface 53a is an arc shape when viewed from the vehicle width direction D2. When viewed from the vehicle width direction D2, the curvature of the arc-shaped contact surface 53a is equal to the curvature of the outer surface 32a.

[0039] The coefficient of kinetic friction of the braking member 53 is, for example, larger than that of the first arm portion 52. The material of the braking member 53 is, for example, rubber or resin.

[0040] The inclined portion 54 extends upward from the support shaft 41 toward a position above the support shaft 41. When the angle of the vehicle body of the towed vehicle 1 with respect to the horizontal plane H becomes a predetermined angle or more, the inclined portion 54 inclines toward the front wheel axle 32. The inclined portion 54 rotates in the rotational direction or the reverse rotational direction around the support shaft 41. "The inclined portion 54 inclines toward the front wheel axle 32" includes that the inclined portion 54 rotates around the support shaft 41 so that the end portion of the inclined portion 54 on the side opposite to the front wheel axle 32 approaches the front wheel axle 32. The inclined portion 54 has a second arm portion 55 and a mass body 56.

[0041] The second arm portion 55 extends upward from the support shaft 41 toward a position above the support shaft 41. The second arm portion 55 is a portion different from the first arm portion 52. In the present embodiment, the second arm portion 55 extends upward from the outer peripheral surface of the base portion 51 toward a position above the support shaft 41. The second arm portion 55 has a rectangular parallelepiped shape (see FIG. 2). In the released state, the second arm portion 55 forms an angle θ (predetermined angle) with respect to the vertical direction D3. The angle θ is, for example, 1.1° or more and 11.3° or less (2.9° as an example). In the released state, the second arm portion 55 extends rearward of the towed vehicle 1 from the support shaft 41.

[0042] The second arm portion 55 forms a predetermined angle with the first arm portion 52. The predetermined angle is, for example, 60° or more and 120° or less. In the present embodiment, the second arm portion 55 forms a right angle (90°) with the first arm portion 52. The angle formed by the second arm portion 55 and the first arm portion 52 is fixed.

[0043] In this embodiment, the mass body 56 is provided at the end of the second arm portion 55 opposite to the support shaft 41. The mass body 56 has a rectangular parallelepiped shape (see FIG. 2). For example, the mass of the mass body 56 is greater than the total mass of the base portion 51, the first arm portion 52, the braking member 53, and the second arm portion 55.

[0044] Fig. 4 is a schematic cross-sectional view showing the towed vehicle 1 in a braking state. Fig. 4 is a cross-sectional view of the towed vehicle 1 cut at a cross section perpendicular to the vehicle width direction D2. In the example of Fig. 4, the towed vehicle 1 is located on a slope S having a gradient φ, and the angle of the body of the towed vehicle 1 with respect to a horizontal plane H is equal to or larger than a predetermined angle.

[0045] When the towed vehicle 1 travels on a slope S having a gradient equal to or greater than a predetermined value, the angle of the body of the towed vehicle 1 with respect to the horizontal plane H becomes equal to or greater than a predetermined angle. When the center of gravity of the braking unit 5 approaches the front wheel set 32 ​​more closely than the support shaft 41, the braking unit 5 rotates in the counter-rotation direction about the vehicle width direction D2, and the towed vehicle 1 transitions from the released state to the braking state. At this time, the inclined unit 54 (the second arm unit 55 and the mass body 56) inclines toward the front wheel set 32, and the first arm unit 52 approaches the front wheel set 32. In the braking state, the braking member 53 comes into contact with the front wheel set 32, applying a braking force to the front wheel set 32.

[0046] When the towed vehicle 1 travels on a horizontal plane H (or a slope having a gradient less than a predetermined value), the angle of the body of the towed vehicle 1 with respect to the horizontal plane H becomes less than a predetermined angle. When the center of gravity of the braking unit 5 moves farther from the front wheel set 32 ​​than the support shaft 41, the braking unit 5 rotates in a rotational direction about the vehicle width direction D2, and the towed vehicle 1 transitions from a braked state to a released state. At this time, the inclined portion 54 tilts in a direction away from the front wheel set 32, and the first arm portion 52 moves away from the front wheel set 32. In the released state, the braking member 53 moves away from the front wheel set 32, and the application of braking force to the front wheel set 32 ​​is released.

[0047] Next, the effects of the towed vehicle 1 and the towing system 10 will be described. Fig. 5(a) is a schematic diagram showing a towing system 100 according to a comparative example. The arrows shown in Figs. 5(a) and 5(b) indicate the frictional force acting between the wheels of each vehicle and the slope S, with the thicker the arrow, the greater the frictional force. The towing system 100 differs from the towing system 10 in that it is provided with a towed vehicle 1A instead of the towed vehicle 1. The towed vehicle 1A differs from the towed vehicle 1 in that it is not provided with a braking mechanism 4.

[0048] Since the towed vehicle 1A is not equipped with a braking mechanism 4, in the towing system 100, when the towing vehicle 20 and the towed vehicle 1A stop on the slope S, the weight of the towing vehicle 20 and the towed vehicle 1A is supported by the braking force of the towing vehicle 20 alone.

[0049] The braking force of the towing vehicle 20 depends on the frictional force between the wheels of the towing vehicle 20 and the slope S. Since the frictional force is determined by, for example, the mass of the towing vehicle 20, the contact area, and the material of the wheels, there is a limit to how much the frictional force can be improved. Therefore, in the towing system 100, the frictional force between the wheels of the towing vehicle 20 and the slope S is insufficient for the force required to support the weight of the towing vehicle 20 and the towed vehicle 1A, and there is a possibility that the towing vehicle 20 and the towed vehicle 1A will slide down the slope S.

[0050] To cope with such a problem, it is conceivable to secure a braking force by applying the brakes of not only the towing vehicle but also the towed vehicle. As a method of applying the brakes of the towed vehicle, for example, it is conceivable to couple the towing vehicle and the towed vehicle to each other via a coupling device disclosed in Japanese Patent Laid-Open Publication No. 9-109872. However, this coupling device expands and contracts in the front-rear direction when the brake device of the towed vehicle is activated. Therefore, when a towed vehicle is towing a plurality of towed vehicles, the speeds of the towed vehicles may vary when the brakes of the towing vehicle are activated, and each towed vehicle may vibrate in the front-rear direction. Therefore, even when the towing vehicle and the towed vehicle are coupled to each other via a coupler that cannot expand and contract in the front-rear direction, it is necessary to apply a braking force to the towed vehicle.

[0051] In the towed vehicle 1 and towing system 10, when the towed vehicle 1 travels on the slope S and the angle of the body of the towed vehicle 1 with respect to the horizontal plane H becomes equal to or greater than a predetermined angle, the inclined portion 54 inclines toward the front wheel set 32. As the inclined portion 54 inclines toward the front wheel set 32, the braking portion 5 rotates about the vehicle width direction D2 in the counter-rotational direction relative to the support shaft 41. As a result, the towed vehicle 1 transitions from the released state to the braked state, and the braking member 53 comes into contact with the front wheel set 32. As a result of the braking member 53 coming into contact with the front wheel set 32, a braking force is applied to the front wheel set 32.

[0052] 5(b) is a schematic diagram showing the towing system 10 according to this embodiment. In the towing system 10, a braking force can be applied to the front axle 32 of the towed vehicle 1 on the slope S. As a result, when the towing vehicle 20 and the towed vehicle 1 stop on the slope S, the weight of the towing vehicle 20 and the towed vehicle 1 can be supported not only by the towing vehicle 20 but also by the braking force of the towed vehicle 1. Therefore, the possibility of slipping down the slope S can be reduced.

[0053] Furthermore, when the towed vehicle 1 in the braked state travels on the horizontal plane H and the angle of the body of the towed vehicle 1 with respect to the horizontal plane H becomes less than a predetermined angle, the braking unit 5 rotates in the vehicle width direction D2 in the rotational direction relative to the support shaft 41. As a result, the towed vehicle 1 transitions from the braked state to the released state. In the released state, the braking member 53 provided on the opposite side of the first arm portion 52 to the support shaft 41 moves away from the front wheel set 32, so that no braking force is applied to the front wheel set 32 ​​by the braking member 53. Therefore, since no braking force is applied to the front wheel set 32 ​​while traveling on the horizontal plane H, the towed vehicle 1 can be efficiently towed on the horizontal plane H.

[0054] The inclined portion 54 extends from the support shaft 41 upward beyond the support shaft 41, and has a second arm portion 55 different from the first arm portion 52, and a mass body 56 provided on the second arm portion 55 opposite the support shaft 41, and in the released state, the second arm portion 55 forms a predetermined angle with respect to the vertical direction D3. In the braking state, the braking member 53 comes into contact with the front wheel axle 32, and is pressed against the front wheel axle 32 by the weight of the mass body 56 provided on the second arm portion 55 opposite the support shaft 41. This makes it easier to ensure the braking force applied to the front wheel axle 32.

[0055] The braking member 53 has a contact surface 53a that comes into contact with the front wheel axle 32, and the contact surface 53a has a shape that corresponds to the shape of the outer surface 32a of the front wheel axle 32. This ensures a wide contact area between the contact surface 53a of the braking member 53 and the outer surface 32a of the front wheel axle 32 in the braking state. This makes it easier to ensure the braking force applied to the front wheel axle 32.

[0056] If the braking mechanism were provided rearward of the rear axle in the longitudinal direction and the braking member were to come into contact with the rear axle to apply a braking force to the rear axle, the braking mechanism could interfere with another towed vehicle connected to the towed vehicle. In this regard, in the towed vehicle 1, the braking mechanism 4 is provided between the front axle 32 and the rear axle 35 in the longitudinal direction D1. This reduces the possibility of the braking mechanism 4 interfering with another towed vehicle 1.

[0057] The present disclosure is not limited to the above embodiment. The inclined portion 54A according to the modified example will be described with reference to FIG. 6. FIG. 6(a) is a cross-sectional view showing the inclined portion 54A according to the modified example in the released state. FIG. 6(b) is a cross-sectional view showing the inclined portion 54A according to the modified example in the braking state. Below, differences from the above embodiment will be mainly described, and overlapping descriptions will be omitted as appropriate.

[0058] Inclined portion 54A differs from inclined portion 54 in that it has mass body 56A instead of mass body 56. Mass body 56A has a storage portion 71 and a swinging body 72. In this modification, storage portion 71 has a rectangular box shape. Storage portion 71 has a bottom portion 73 attached to second arm portion 55, a top portion 74 facing bottom portion 73 in the direction in which second arm portion 55 extends, and a side portion 75 connecting bottom portion 73 and top portion 74 to each other. Box-shaped storage portion 71 has an internal space 70.

[0059] The internal space 70 has a height in the direction in which the second arm portion 55 extends (hereinafter referred to as the "height direction"). The internal space 70 has a length in the vehicle width direction D2 (hereinafter referred to as the "length direction"). The internal space 70 has a width in a direction perpendicular to both the direction in which the second arm portion 55 extends and the vehicle width direction D2 (hereinafter referred to as the "width direction").

[0060] The oscillating body 72 is accommodated in the accommodation portion 71. The oscillating body 72 is capable of oscillating in the width direction of the internal space 70 inside the accommodation portion 71. In this modified example, the oscillating body 72 is spherical. However, the shape of the oscillating body 72 is not particularly limited, and may be, for example, a cylindrical shape extending in the length direction of the internal space 70. The diameter of the oscillating body 72 is smaller than the height and width of the internal space 70.

[0061] The mass body 56A in the released state will be described. As shown in Fig. 6(a), in the released state, the bottom 73 of the storage section 71 is inclined toward the rear of the towed vehicle 1. In this modification, the rocking body 72 is in contact with the side surface portion 75 farther from the front wheel set 32 ​​out of a pair of side surface portions 75 opposing each other in the width direction of the internal space 70. The rocking body 72 is located at a position farther from the front wheel set 32 ​​than the support shaft 41 (see Fig. 3). The rocking body 72 is located at a position farther from the front wheel set 32 ​​than the second arm portion 55.

[0062] The mass body 56A in the braking state will be described. As shown in FIG. 6(b), in the braking state, the bottom 73 of the storage section 71 is inclined toward the front of the towed vehicle 1. When the towed vehicle 1 transitions from the released state to the braking state, the rocking body 72 rocks toward the front of the towed vehicle 1 along the bottom 73 of the storage section 71. In this modification, in the braking state, the rocking body 72 is in contact with the side surface portion 75, which is closer to the front wheel axle 32, of a pair of side surface portions 75 opposed to each other in the width direction of the internal space 70. The rocking body 72 is located closer to the front wheel axle 32 than the support shaft 41. The rocking body 72 is located closer to the front wheel axle 32 than the second arm portion 55.

[0063] In this modification, the mass body 56A has a storage section 71 and a swinging body 72 that is stored in the storage section 71 and can swing inside the storage section 71. In this case, when the towed vehicle 1 transitions from the released state to the braking state and the brake section 5 rotates so that the mass body 56A approaches the front wheel set 32, the swinging body 72 swings inside the storage section 71 so as to approach the front wheel set 32. This allows the center of gravity of the mass body 56A in the braking state to be brought closer to the front wheel set 32 ​​compared to, for example, a case in which the mass body 56A does not have the swinging body 72. As a result, the brake member 53 can be pressed more strongly against the front wheel set 32 ​​by the weight of the mass body 56A, and therefore a greater braking force can be applied to the front wheel set 32.

[0064] In the above embodiment, an example has been described in which the second arm portion 55 forms an angle θ with respect to the vertical direction D3 in the released state. However, the angle that the second arm portion 55 forms with respect to the vertical direction D3 in the released state may be changeable. For example, the angle that the second arm portion 55 forms with the first arm portion 52 may be changeable. As a configuration that enables the angle that the second arm portion 55 forms with respect to the vertical direction D3 in the released state to be changed, for example, a known configuration may be adopted.

[0065] In this modified example, the angle formed by the second arm portion 55 with respect to the vertical direction D3 in the released state is changeable. In this case, by adjusting the angle formed by the second arm portion 55 with respect to the vertical direction D3 in the released state, the angle of the vehicle body of the towed vehicle 1 when the towed vehicle 1 transitions from the released state to the braking state can be adjusted. Therefore, braking force can be applied to the towed vehicle 1 on an inclined surface having a desired gradient.

[0066] In the above-described embodiment, an example in which the inclined portion 54 has the second arm portion 55 has been described. However, the inclined portion 54 may not have the second arm portion 55. In this case, the mass body 56 may be directly attached to the support shaft 41.

[0067] In the above-described embodiment, an example in which the support shaft 41 is provided above and behind the front wheel shaft 32 has been described. However, the support shaft 41 may be provided below and behind the front wheel shaft 32.

[0068] In the above-described embodiment, an example in which the braking member 53 has a fan shape and the contact surface 53a of the braking member 53 has an arc shape when viewed in the vehicle width direction D2 has been described. However, the shape of the braking member 53 is not particularly limited, and for example, it may have a flat plate shape. In this case, the contact surface 53a of the braking member 53 has a linear shape when viewed in the vehicle width direction D2.

[0069] [Embodiment 1] A towed vehicle towed by a towing vehicle, A pair of wheels, An axle extending in one direction and to which the pair of wheels are attached, A braking mechanism for applying a braking force to the axle, and The braking mechanism is Provided at a position spaced apart from the axle in a direction intersecting the one direction, a support shaft extending in the one direction, and A braking portion rotatably supported by the support shaft around the one direction. The braking unit is capable of transitioning between a braking state in which the braking force is applied to the axle and a release state in which the application of the braking force to the axle is released by rotating about the support shaft in the one direction, The braking portion includes: a first arm portion extending from the support shaft toward above the axle; a braking member provided on the first arm portion on an opposite side to the support shaft, the braking member applying the braking force to the axle; an inclined portion extending from the support shaft upward beyond the support shaft and inclining toward the axle when an angle of the body of the towed vehicle relative to a horizontal plane becomes equal to or greater than a predetermined angle; In the released state, the braking member is spaced from the axle; In the braking state, the braking member contacts the axle and the braking force is applied to the axle. [Form 2] The inclined portion is A second arm portion that extends upward from the support shaft and is different from the first arm portion; a mass body provided on the second arm portion on the opposite side to the support shaft, 2. The towed vehicle according to claim 1, wherein in the released state, the second arm portion forms a predetermined angle with respect to the up-down direction. [Form 3] 3. The towed vehicle according to claim 2, wherein an angle that the second arm portion makes with respect to the up-down direction in the released state is changeable. [Form 4] The mass is A storage section; The towed vehicle according to claim 2 or 3, further comprising: a rocking body that is accommodated in the accommodation section and is capable of rocking inside the accommodation section. [Form 5] The braking member has a contact surface that contacts the axle, 5. The towed vehicle according to any one of the first to fourth embodiments, wherein the contact surface has a shape corresponding to a shape of an outer surface of the axle. [Form 6] The towed vehicle according to any one of aspects 1 to 5, A towing system comprising: a towing vehicle that tows the towed vehicle. [Explanation of symbols]

[0070] 1...towed vehicle, 4...braking mechanism, 5...braking section, 10...traction system, 20...towing vehicle, 31...front wheel (wheel), 32...front wheel axle, 32a...outer surface, 41...support shaft, 52...first arm section, 53...braking member, 53a...contact surface, 54, 54A...inclined section, 55...second arm section, 56, 56A...mass body, 71...accommodation section, 72...oscillating body, D2...vehicle width direction (one direction), D3...vertical direction, θ...angle (predetermined angle).

Claims

1. A towed vehicle towed by a towing vehicle, A pair of wheels, an axle extending in one direction and having the pair of wheels attached thereto; a braking mechanism for applying a braking force to the axle; The braking mechanism includes: a support shaft provided at a position spaced apart from the axle in a direction intersecting the one direction and extending in the one direction; a braking portion supported by the support shaft so as to be rotatable around the one direction, The braking unit is capable of transitioning between a braking state in which the braking force is applied to the axle and a release state in which the application of the braking force to the axle is released by rotating about the support shaft in the one direction, The braking portion includes: a first arm portion extending from the support shaft toward above the axle; a braking member provided on the first arm portion on an opposite side to the support shaft, the braking member applying the braking force to the axle; an inclined portion extending from the support shaft upward beyond the support shaft and inclining toward the axle when an angle of the body of the towed vehicle relative to a horizontal plane becomes equal to or greater than a predetermined angle; In the released state, the braking member is spaced from the axle; In the braking state, the braking member contacts the axle and the braking force is applied to the axle.

2. The inclined portion is a second arm portion extending upward from the support shaft and different from the first arm portion; a mass body provided on the second arm portion on an opposite side to the support shaft, 2. The towed vehicle according to claim 1, wherein in the released state, the second arm portion forms a predetermined angle with respect to the vertical direction.

3. The towed vehicle according to claim 2 , wherein an angle that the second arm portion forms with respect to the vertical direction in the released state is changeable.

4. The mass is A storage section; 4. The towed vehicle according to claim 2 or 3, further comprising: a swinging body that is accommodated in the accommodation portion and is swingable within the accommodation portion.

5. The braking member has a contact surface that contacts the axle, The towed vehicle according to any one of claims 1 to 3, wherein the contact surface has a shape corresponding to a shape of an outer surface of the axle.

6. The towed vehicle according to any one of claims 1 to 3, A towing system comprising: a towing vehicle that tows the towed vehicle.

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