Multi-wheeled conveyance vehicle

Abstract

To provide a multi-wheeled conveyance vehicle exhibiting excellent step ride-over performance without raising the gravity center of a vehicle body.SOLUTION: The multi-wheeled conveyance vehicle 1 includes a vehicle body, drive wheels, front wheels, and rear wheels. A drive-wheel spring rate k20 is set to be smaller than a front-wheel spring rate k30 and smaller than a rear-wheel spring rate k40. The amount of drive-wheel travel T20, the amount of front-wheel travel T30, and the amount of rear-wheel travel T40 are set so as to at least partially overlap one another in an assumed load range NML. The amount of drive-wheel travel T20 is set to produce a preload range PLL. The amount of front-wheel travel T30 is set so as to allow movement of each front wheel in a high load range HL. The amount of rear-wheel travel T40 is set so as to allow movement of each rear wheel in the assumed load range NML including the high load range HL.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The disclosure in this specification relates to a multi-wheel guided vehicle. [Background technology]

[0002] Patent Document 1 discloses a multi-wheeled vehicle with four or more wheels that has excellent running performance. Patent Document 1 also discloses a six-wheeled vehicle that has a pair of front wheels, a pair of middle wheels, and a pair of rear wheels. The contents of the prior art documents are incorporated by reference as explanations of the technical elements in this specification. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-61342 Summary of the Invention [Problem to be solved by the invention]

[0004] In the structure disclosed in Patent Document 1, when the passenger or load is heavy and the load on the front wheels is large, the ability to overcome steps is impaired. Conversely, when the passenger or load is light, the center of gravity of the entire vehicle body is high. A high center of gravity impairs the stability of the vehicle body. In the above-mentioned respects and in other respects not mentioned, further improvements are required for multi-wheeled guided vehicles.

[0005] One disclosed object is to provide a multi-wheeled transport vehicle that exhibits excellent step-climbing performance without raising the center of gravity of the vehicle body. [Means for solving the problem]

[0006] The multi-wheel transporter disclosed herein includes a vehicle body (10), at least one drive wheel (20), and a drive wheel suspension device (21) that supports the drive wheel so as to be movable at least vertically with respect to the vehicle body. The drive wheel suspension device (21) includes a drive wheel suspension (24) that applies a drive wheel spring rate (k20) over a drive wheel travel amount (T20) of the drive wheel. It also includes at least one front wheel (30) disposed in front of the drive wheel in the traveling direction and driven to rotate in accordance with the rotation of the drive wheel, and a front wheel suspension device (31) that supports the front wheel so as to be movable at least vertically with respect to the vehicle body. The front wheel suspension device (31) includes a front wheel suspension (34) that applies a front wheel spring rate (k30) over a front wheel travel amount (T30) of the front wheel. It further includes at least one rear wheel (40) disposed behind the drive wheel in the reverse direction and driven to rotate in accordance with the rotation of the drive wheel, and a rear wheel suspension device (41) that supports the rear wheel so as to be movable at least vertically with respect to the vehicle body. The rear wheel suspension device (41) includes a rear wheel suspension (44) that applies a rear wheel spring rate (k40) over a rear wheel travel amount (T40) of the rear wheel. Further, the drive wheel spring rate (k20) is set to be smaller than the front wheel spring rate (k30) and smaller than the rear wheel spring rate (k40) (k20 < k30, k20 < k40). Further, the drive wheel travel amount, the front wheel travel amount, and the rear wheel travel amount are set such that at least a part thereof overlaps in an assumed load range (NML) that extends from an unloaded state (DW) that supports only the self-weight to a maximum load state (DW + Lmax) that supports the assumed maximum load and the self-weight. Further, the drive wheel travel amount is set to generate a preliminary load range (PLL) in which only the drive wheel is in contact with the ground in a low load state that is smaller than the unloaded state. Further, the front wheel travel amount is set to allow the movement of the front wheel in a high load range (HL) that includes the maximum load state of the assumed load range. Further, the rear wheel travel amount is set to allow the movement of the rear wheel in the assumed load range that includes the high load range.

[0007] The disclosed multi-wheel guided vehicle can create a preload range in which only the drive wheels contact the ground under low load conditions. Furthermore, the drive wheel spring rate acting on the drive wheels is set smaller than the front wheel spring rate and smaller than the rear wheel spring rate. As a result, the drive wheel suspension system achieves long drive wheel travel with a soft spring rate. This allows the ground load of the drive wheels to be relatively high and the ground loads of the front and rear wheels to be low. Furthermore, the front wheel travel is set to allow front wheel movement in a high load range, including the maximum load state within the expected load range. Meanwhile, the rear wheel travel is set to allow rear wheel movement within an expected load range, including the high load range. As a result, the front and rear wheels impart a rearward-leaning posture to the vehicle body within the expected load range. In other words, the front and rear wheels create a tilted front posture within the expected load range. As a result, the load on the front wheels is suppressed.

[0008] The various embodiments disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and in this section are intended to exemplify the correspondence with the following embodiments and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view of a multi-wheel guided vehicle according to a first embodiment. [Figure 2] FIG. 2 is a left side view of the multi-wheel guided vehicle with the drive wheels removed. [Figure 3] FIG. 2 is a right side view of the multi-wheel guided vehicle with the drive wheels removed. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 2 is a side view showing the multi-wheel guided vehicle in a lifted state. [Figure 9] FIG. 10 is a side view showing a state in which only the drive wheels of the multi-wheel guided vehicle are in contact with the ground. [Figure 10] FIG. 10 is a side view showing a state in which all wheels of the multi-wheeled guided vehicle are in contact with the ground. [Figure 11] 10 is a graph showing the relationship between the travel amount and the load of a plurality of wheels. [Figure 12] FIG. 10 is a side view showing the multi-wheel guided vehicle in a rearward tilted state. DETAILED DESCRIPTION OF THE INVENTION

[0010] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals or reference numerals that differ in the hundredth or more digits. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0011] In the following description, when at least one component includes a pair of components, the components may be identified by adding suffix symbols R and L. For example, the right drive wheel 20R and the left drive wheel 20L described below are identified by suffix symbols R and L. When at least one component is described collectively, it may be identified by a number without a suffix symbol. For example, at least one drive wheel 20 is identified by a numerical symbol only. For example, a description of the drive wheel 20 is applicable to both the right drive wheel 20R and the left drive wheel 20L.

[0012] First embodiment In FIG. 1, the multi-wheel carrier 1 has a vehicle body 10. The vehicle body 10 functions as a frame that defines the structure of the multi-wheel carrier 1. Further, the vehicle body 10 functions as a base for positioning the load or the passenger at a specified position. In this embodiment, the multi-wheel carrier 1 provides a moving cart for carrying a load. The moving cart is equipped with a power source and can move by self-propulsion. Further, the moving cart can be moved manually by an operator pushing or pulling it. Instead of this embodiment, the multi-wheel carrier 1 may carry a human seat. In this case, the multi-wheel carrier 1 provides a moving cart for a wheelchair.

[0013] The multi-wheel carrier 1 has at least one drive wheel 20. The multi-wheel carrier 1 has at least one front wheel 30. The multi-wheel carrier 1 has at least one rear wheel 40. The multi-wheel carrier 1 of this embodiment is a six-wheel carrier. Note that instead of this embodiment, the multi-wheel carrier 1 can take various forms such as five wheels, seven wheels, eight wheels, etc.

[0014] The drive wheel 20 has a diameter D20. The diameter D20 of the drive wheel 20 is the largest among the wheels of the multi-wheel carrier 1. The front wheel 30 has a diameter D30. The diameter D30 of the front wheel 30 is smaller than the diameter D20 of the drive wheel 20 (D30 < D20). The diameter D30 of the front wheel 30 is smaller than half of the diameter D20 of the drive wheel 20 (D30 < 1 / 2 × D20). The rear wheel 40 has a diameter D40. The diameter D40 of the rear wheel 40 is smaller than the diameter D20 of the drive wheel 20 (D40 < D20). The diameter D40 of the rear wheel 40 is smaller than half of the diameter D20 of the drive wheel 20 (D40 < 1 / 2 × D20). The diameter D40 of the rear wheel 40 is the same as the diameter D30 of the front wheel 30.

[0015] 1 to 7 show a multi-wheel guided vehicle 1 positioned in a stationary state on a travel surface GND. The multi-wheel guided vehicle 1 has a center of gravity GC. The center of gravity GC is located on a center of gravity axis GCX. The figures show the center of gravity GC in an unloaded state in which the multi-wheel guided vehicle 1 is supporting only its own weight. When the multi-wheel guided vehicle 1 is loaded with an object to be transported, such as a cargo or a person, the center of gravity of the cargo is located on the center of gravity axis GCX.

[0016] In Fig. 1, the multi-wheel guided vehicle 1 has at least one drive wheel 20. The drive wheel 20 has a tire portion made of rubber and filled with air. The drive wheel 20 is rotated by a drive unit 50 mounted on the vehicle body 10. The drive wheel 20 can rotate forward and backward.

[0017] The multi-wheel guided vehicle 1 has a drive wheel suspension device 21. The drive wheel suspension device 21 supports the drive wheels 20 with respect to the vehicle body 10. The drive wheel suspension device 21 supports the drive wheels 20 so that they can move at least in the vertical direction. Movement in the vertical direction includes movement in the upward direction UD and movement in the downward direction DD.

[0018] 2, the drive wheels 20 are supported by wheel hubs 22. The drive wheel suspension 21 supports the wheel hubs 22, thereby supporting the drive wheels 20.

[0019] 1, the drive wheel suspension system 21 includes a drive wheel suspension 24. The drive wheel suspension 24 controls the behavior of the drive wheels 20 via the drive wheel suspension system 21.

[0020] 11, the drive wheel suspension 24 applies a drive wheel spring rate k20 to the drive wheel 20 over a drive wheel travel amount T20 of the drive wheel 20. The drive wheel spring rate k20 is expressed as the slope of a characteristic line WT20.

[0021] FIG. 11 is a graph showing the relationship between the travel and load of multiple wheels. The horizontal axis shows the load WGT (kg) applied to the wheels. The vertical axis shows the wheel travel TVL (mm). The graph is drawn assuming that the preload PL20 in the drive wheel suspension 21 is 0 (zero). Preload is the load pre-applied to the suspension. Preload may also be understood as the load pre-applied to the suspension springs. The preload difference DPL indicates the difference between the preload PL30 in the front wheel suspension 31 and the preload PL40 in the rear wheel suspension 41.

[0022] The behavior of the drive wheels 20 is shown by the characteristic line WT20. The behavior of the front wheels 30 is shown by the characteristic line WT30. The behavior of the rear wheels 40 is shown by the characteristic line WT40. On the horizontal axis, the multi-wheel guided vehicle 1 has a dead weight DW. The multi-wheel guided vehicle 1 is designed to withstand the expected maximum load Lmax. Therefore, the multi-wheel guided vehicle 1 exhibits the target performance within the expected load range NML.

[0023] In FIG. 1, the multi-wheel guided vehicle 1 has at least one front wheel 30. The front wheel 30 is disposed forward of the drive wheels 20 in the forward direction FWD. The multi-wheel guided vehicle 1 is capable of moving in all directions, but the forward direction FWD is the main direction of travel in terms of design. The forward direction is also called the main forward direction. The front wheel 30 is a driven wheel that follows the rotation of the drive wheels 20. The front wheel 30 is also called a driven front wheel.

[0024] The multi-wheel guided vehicle 1 has a front wheel suspension device 31. The front wheel suspension device 31 supports the front wheels 30 relative to the vehicle body 10. The front wheel suspension device 31 supports the front wheels 30 so that they can move at least in the vertical direction. The front wheel suspension device 31 is provided with a swivel base 32. The front wheels 30 are connected to the swivel base 32. The swivel base 32 allows the front wheels 30 to be steered freely. The front wheels 30 and the swivel base 32 are supported by swivel casters.

[0025] The front wheel suspension 31 includes a front wheel suspension 34. The front wheel suspension 34 controls the behavior of the front wheels 30 via the front wheel suspension 31.

[0026] As shown in Figure 11, the front wheel suspension 31 applies a front wheel spring rate k30 to the front wheel 30 over a front wheel travel amount T30 of the front wheel 30. In Figure 11, the front wheel spring rate k30 is shown as the slope of a suspension characteristic line WT30.

[0027] In FIG. 1, the multi-wheel guided vehicle 1 has at least one rear wheel 40. The rear wheel 40 is disposed rearward of the drive wheels 20 in the reverse direction RVD. The reverse direction RVD is the opposite direction to the forward direction FWD. The rear wheel 40 is a driven wheel that follows the rotation of the drive wheels 20. The rear wheel 40 is also called a driven rear wheel.

[0028] The multi-wheel guided vehicle 1 has a rear wheel suspension device 41. The rear wheel suspension device 41 supports the rear wheels 40 relative to the vehicle body 10. The rear wheel suspension device 41 supports the rear wheels 40 so that they can move at least in the vertical direction. The rear wheel suspension device 41 is provided with a swivel base 42. The rear wheels 40 are connected to the swivel base 42. The swivel base 42 allows the rear wheels 40 to be steered freely. The rear wheels 40 and the swivel base 42 are provided by swivel casters.

[0029] The rear wheel suspension 41 includes a rear wheel suspension 44. The rear wheel suspension 44 controls the behavior of the rear wheel 40 via the rear wheel suspension 41.

[0030] As shown in Fig. 11, the rear wheel suspension 41 applies a rear wheel spring rate k40 to the rear wheel 40 over a rear wheel travel amount T40 of the rear wheel 40. In Fig. 11, the rear wheel spring rate k40 is shown as the slope of a suspension characteristic line WT40.

[0031] In FIG. 1, the drive wheel suspension device 21, the front wheel suspension device 31, and / or the rear wheel suspension device 41 may additionally move the wheel in the vehicle width direction, the longitudinal direction, etc. as the wheel moves vertically. Further, these suspension devices may change the alignment such as the camber angle.

[0032] The drive wheel suspension 24, the front wheel suspension 34, and / or the rear wheel suspension 44 have a spring and a damper. The spring in this embodiment is a coil spring. Instead of this, the spring may be provided by an air spring, an electromagnetic spring, etc. The damper in this embodiment is an oil damper. Instead of this, the damper may be provided by a gas damper, a friction damper, etc.

[0033] In FIG. 11, the drive wheel spring rate k20 provided by the drive wheel suspension device 21 to the drive wheel 20 is set smaller than the front wheel spring rate k30 provided by the front wheel suspension device 31 to the front wheel 30 (k20 < k30). The drive wheel spring rate k20 is set smaller than the rear wheel spring rate (k40) provided by the rear wheel suspension device 41 to the rear wheel 40 (k20 < k40). Therefore, the drive wheel 20 is supported more softly than the front wheel 30 and the rear wheel 40. As a result, a stable grounding state of the drive wheel 20 can be obtained.

[0034] The drive wheel travel amount T20, the front wheel travel amount T30, and the rear wheel travel amount T40 are set such that at least a part overlaps in the assumed load range NML. The assumed load range NML corresponds to the design load range assumed for the multi-wheel carrier 1. The multi-wheel carrier 1 is designed to exhibit the target running performance in the no-load state DW that supports only its own weight DW. The multi-wheel carrier 1 is designed to exhibit the target running performance in the maximum load state DW + Lmax that supports the assumed maximum load Lmax and its own weight DW. The multi-wheel carrier 1 is designed to exhibit the target running performance in the assumed load range NML that extends from the no-load state DW to the maximum load state DW + Lmax.

[0035] The drive wheel travel T20 is spread over a load range wider than the expected load range NML. The drive wheel travel T20 is spread over a wide range both below the expected load range NML and above the expected load range NML. The rear wheel travel T40 is spread slightly narrower over a load range lower than the expected load range NML. This load range is clearly narrower than the pre-load range PLL, which will be described later. The rear wheel travel T40 is spread over a wide range higher than the expected load range NML. Throughout the expected load range NML, the drive wheel travel T20 and the rear wheel travel T40 overlap. Therefore, throughout the entire expected load range NML, when the drive wheel 20 moves vertically, the rear wheel 40 also moves vertically.

[0036] The front wheel travel T30 occurs only in a part of the assumed load range NML. The front wheel travel T30 occurs only in the high load range HL of the assumed load range NML. Therefore, the drive wheels 20, rear wheels 40, and front wheels 30 simultaneously move up and down only in the high load range HL of the assumed load range NML. That is, the front wheel travel T30 is set to allow movement of the front wheels 30 in the high load range HL, which includes the maximum load state DW+Lmax of the assumed load range NML. Moreover, the rear wheel travel T40 is set to allow movement of the rear wheels 40 in the assumed load range NML, which includes the high load range HL. As a result, the front wheels 30 and rear wheels 40 assume a rearward-leaning posture in the assumed load range NML. In other words, the front wheels 30 and rear wheels 40 create a tilted-forward posture in the assumed load range NML. As a result, the load on the front wheels 30 is suppressed.

[0037] The drive wheel travel T20 is set to generate a preload range PLL in which only the drive wheels 20 contact the ground when the load is lower than the no-load state DW. The drive wheel travel T20 includes an expected travel TNM in the expected load range NML and a preload travel TPL in the preload range PLL. The preload range PLL and / or the preload travel TPL enable the drive wheels 20 to contact the ground stably.

[0038] As shown in the pair of Figures 2 and 3, the pair of Figures 4 and 5, and the pair of Figures 6 and 7, the multi-wheel guided vehicle 1 has a right wheel system and a left wheel system symmetrically arranged on the right side (RGT) and left side (LFT) of the vehicle body 10. Each wheel system includes drive wheels 20, front wheels 30, and rear wheels 40. The multi-wheel guided vehicle 1 is a six-wheel guided vehicle having a total of six wheels.

[0039] The drive wheels 20 include a right drive wheel 20R disposed on the right side of the vehicle body 10. The drive wheels 20 include a left drive wheel 20L disposed on the left side of the vehicle body 10.

[0040] In FIG. 2, the driving wheel suspension 21 has a left driving wheel suspension 21L. The left driving wheel suspension 21L has a left wheel hub 22L. The left driving wheel suspension 21L supports the left driving wheel 20L via the left wheel hub 22L. The left driving wheel 20L is supported so that it can rotate but cannot turn for steering. The left driving wheel suspension 21L has a left driving wheel suspension 24L. The left driving wheel suspension 24L elastically supports the left driving wheel 20L with respect to vertical movement of the left driving wheel 20L.

[0041] 4 and 5, the left driving wheel suspension 21L is an arm-type suspension. The left driving wheel suspension 21L includes at least one swing arm. The swing arm is journaled on at least one swing shaft extending in the front-to-rear direction of the vehicle body 10. The swing arm extends toward the left side LFT in the width direction of the vehicle body 10, and supports the left driving wheel 20L in an unsteerable manner.

[0042] The right driving wheel suspension 21R has a double wishbone structure. The left driving wheel suspension 21L includes an upper left swing arm 23La and a lower left swing arm 23Lb. The upper left swing arm 23La and the lower left swing arm 23Lb connect the left wheel hub 22L and the vehicle body 10.

[0043] The upper left swing arm 23La is pivotally supported by at least one swing shaft 25La extending in the front-rear direction of the vehicle body 10. The upper left swing arm 23La extends toward the left side LFT in the width direction of the vehicle body 10. The upper left swing arm 23La supports the left driving wheel 20L in an unsteerable manner.

[0044] The lower left swing arm 23Lb is pivotally supported by at least one swing shaft 25Lb extending in the front-to-rear direction of the vehicle body 10. The lower left swing arm 23Lb extends toward the left side LFT in the width direction of the vehicle body 10. The lower left swing arm 23Lb supports the left driving wheel 20L in an unsteerable manner.

[0045] In FIG. 3, the drive wheel suspension 21 has a right drive wheel suspension 21R. The right drive wheel suspension 21R has a right wheel hub 22R. The right drive wheel suspension 21R supports the right drive wheel 20R via the right wheel hub 22R. The right drive wheel 20R is supported so that it can rotate but cannot turn for steering. The right drive wheel suspension 21R has a right drive wheel suspension 24R. The right drive wheel suspension 24R elastically supports the right drive wheel 20R with respect to vertical movement of the right drive wheel 20R.

[0046] 4 and 5, the right driving wheel suspension 21R is a swing arm type suspension. The right driving wheel suspension 21R includes at least one swing arm. The swing arm is journaled on at least one swing shaft extending in the front-to-rear direction of the vehicle body 10. The swing arm extends toward the right side RGT in the width direction of the vehicle body 10, and supports the right driving wheel 20R in an unsteerable manner.

[0047] The right driving wheel suspension 21R has a double wishbone structure and includes an upper right swing arm 23Ra and a lower right swing arm 23Rb, which connect the right wheel hub 22R to the vehicle body 10.

[0048] The right upper swing arm 23Ra is pivotally supported by at least one swing shaft 25Ra extending in the front-rear direction of the vehicle body 10. The right upper swing arm 23Ra extends toward the right side RGT in the width direction of the vehicle body 10. The right upper swing arm 23Ra supports the right drive wheel 20R in an unsteerable manner.

[0049] The lower right swing arm 23Rb is pivotally supported by at least one swing shaft 25Rb extending in the front-to-rear direction of the vehicle body 10. The lower right swing arm 23Rb extends toward the right side RGT in the width direction of the vehicle body 10. The lower right swing arm 23Rb supports the right driving wheel 20R in an unsteerable manner.

[0050] In FIG. 2, the front wheels 30 include a left front wheel 30L disposed on the left side LFT of the vehicle body. The front wheel suspension 31 includes a left front wheel suspension 31L. The left front wheel suspension 31L is a swing arm type suspension. The left front wheel suspension 31L includes a left front swing arm 33L. The left front swing arm 33L is journaled on a swing shaft 35L extending in the width direction of the vehicle body 10. The left front swing arm 33L extends toward the front of the vehicle body 10. The left front swing arm 33L supports the left front wheel 30L via a left front pivot base 32L. The left front pivot base 32L allows the left front wheel 30L to be steered freely.

[0051] In FIG. 3, the front wheels 30 include a right front wheel 30R disposed on the right side RGT of the vehicle body. The front wheel suspension 31 includes a right front wheel suspension 31R. The right front wheel suspension 31R is a swing arm type suspension. The right front wheel suspension 31R includes a right front swing arm 33R. The right front swing arm 33R is journaled on a swing shaft 35R extending in the width direction of the vehicle body 10. The right front swing arm 33R extends toward the front of the vehicle body 10. The right front swing arm 33R supports the right front wheel 30R via a right front turning base 32R. The right front turning base 32R allows the right front wheel 30R to be steered freely.

[0052] In FIG. 2, the rear wheel 40 has a left rear wheel 40L arranged on the left side LFT with respect to the vehicle body 10. The rear wheel suspension has a left rear wheel suspension 41L. The left rear wheel suspension 41L includes a left rear swing arm 43L. The left rear swing arm 43L is journaled on a swing shaft 45L extending in the width direction of the vehicle body 10. The left rear swing arm 43L extends toward the rear of the vehicle body 10. The left rear swing arm 43L supports the left rear wheel 40L via a left rear pivot base 42L. The left rear pivot base 42L allows the left rear wheel 40L to be steered freely.

[0053] In FIG. 3, the rear wheels 40 include a right rear wheel 40R disposed on the right side RGT of the vehicle body 10. The rear wheel suspension includes a right rear wheel suspension 41R. The right rear wheel suspension 41R includes a right rear swing arm 43R. The right rear swing arm 43R is journaled on a swing shaft 45R extending in the width direction of the vehicle body 10. The right rear swing arm 43R extends toward the rear of the vehicle body 10. The right rear swing arm 43R supports the right rear wheel 40R via a right rear pivot base 42R. The right rear pivot base 42R allows the right rear wheel 40R to be steered freely.

[0054] Returning to FIG. 1, the multi-wheel guided vehicle 1 is equipped with a drive unit 50 that rotates the right drive wheel 20R and the left drive wheel 20L. The drive unit 50 moves the multi-wheel guided vehicle 1 by rotating the right drive wheel 20R and the left drive wheel 20L. The drive unit 50 independently controls the rotation speed of the right drive wheel 20R and the rotation speed of the left drive wheel 20L. The drive unit 50 independently controls the rotation direction of the right drive wheel 20R and the rotation direction of the left drive wheel 20L. The drive unit 50 steers the multi-wheel guided vehicle 1 by the difference in rotation between the right drive wheel 20R and the left drive wheel 20L.

[0055] Alternatively or additionally, the multi-wheeled guided vehicle 1 may have a central wheel system between the right wheel system and the left wheel system. For example, the multi-wheeled guided vehicle 1 may have a single drive wheel 20 in the center. In this case, the multi-wheeled guided vehicle 1 has at least a front wheel 30 or a rear wheel 40 provided by a left wheel and a right wheel. The multi-wheeled guided vehicle 1 may also have a single front wheel 30 in the center. In this case, the multi-wheeled guided vehicle 1 has at least a drive wheel 20 or a rear wheel 40 provided by a left wheel and a right wheel. Similarly, the multi-wheeled guided vehicle 1 may have a single rear wheel 40 in the center. In this case, the multi-wheeled guided vehicle 1 has at least a front wheel 30 or a drive wheel 20 provided by a left wheel and a right wheel.

[0056] Figures 8, 9, and 10 show the process of successively bringing the wheels of the multi-wheel guided vehicle 1 into contact with the ground. Figures 8 and 9 show the state in which the vehicle body 10 is lifted while the center of gravity axis GCX is maintained parallel to the direction of gravity. Figure 8 shows the lifted state in which the drive wheels 20, front wheels 30, and rear wheels 40 are all separated from the running surface GND. Figure 9 shows the lifted state in which only the drive wheels 20 are in contact with the running surface GND. Figure 10 shows the state in which the multi-wheel guided vehicle 1 is supporting only its own weight (unloaded state).

[0057] The hatched region VIII in FIG. 11 represents the fully lifted state shown in FIG. 8. The zero (0) position in FIG. 11 indicates the point at which any wheel begins to travel. The zero position is the zero position of the drive wheel travel amount allowed by the drive wheel suspension 21, the drive wheel travel amount allowed by the front wheel suspension 31, and the drive wheel travel amount allowed by the rear wheel suspension 41. In this embodiment, the zero position represents the state shown in FIG. 9 in which only the drive wheels 20 are in contact with the ground. The zero position is also the preload PL20 of the drive wheel suspension 21. Consider a case in which the lifting amount of the vehicle body 10 is reduced from the state shown in FIG. 9. That is, consider a case in which the vehicle body 10 is gradually lowered. From the state shown in FIG. 9, the weight of the multi-wheeled guided vehicle 1 gradually acts on the drive wheel suspension 21. Therefore, in the preload range PLL, the drive wheel suspension 21 gradually operates. As a result of this operation, the drive wheel travel amount T20 gradually increases. The drive wheel suspension 21 applies a drive wheel spring rate k20 to the drive wheels 20 in proportion to the drive wheel travel amount T20.

[0058] The drive wheel travel T20 includes a spare travel TPL and an expected travel TNM. The spare travel TPL is the travel of the drive wheel 20 in the spare load range PLL. The expected travel TNM is the travel of the drive wheel 20 in the expected load range NML. The spare travel TPL is wider than the expected travel TNM. This allows the drive wheel 20 to obtain the necessary ground contact pressure.

[0059] After the state shown in Figure 9, the front wheel 30 and / or the rear wheel 40 eventually touch the ground. In this embodiment, both the front wheel 30 and the rear wheel 40 touch the ground at approximately the same time. However, due to the difference DPL between the preload PL40 and the preload PL30, the rear wheel suspension 41 operates before the front wheel suspension 31. The preload PL30 is the preload of the front wheel suspension 31. The preload PL40 is the preload of the rear wheel suspension 41. The rear wheel preload PL40 that preloads the rear wheel suspension 43 is set to be smaller than the front wheel preload PL30 that preloads the front wheel suspension 33.

[0060] From the preload PL40 in FIG. 11, the rear-wheel suspension device 41 gradually operates. Along with this operation, both the drive-wheel travel amount T20 and the rear-wheel travel amount T40 gradually increase. The rear-wheel suspension device 41 applies a rear-wheel spring rate k40 to the rear wheel 40 in proportion to the rear-wheel travel amount T40.

[0061] When the load WGT further increases, eventually, the front-wheel suspension device 31 operates. From the preload PL30 in FIG. 11, the front-wheel suspension device 31 gradually operates. Along with this operation, all of the drive-wheel travel amount T20, the rear-wheel travel amount T40, and the front-wheel travel amount T30 gradually increase. The front-wheel suspension device 31 applies a front-wheel spring rate k30 to the front wheel 30 in proportion to the front-wheel travel amount T30. The rear-wheel spring rate k40 is set to be smaller than the front-wheel spring rate k30 (k40 < k30).

[0062] In the assumed load range NML exceeding the preliminary load range PLL, the drive-wheel travel amount T20 and the rear-wheel travel amount T40 overlap. The rear-wheel travel amount T40 extends over the entire assumed load range NML. Furthermore, the rear-wheel travel amount T40 extends into a part of the preliminary load range PLL. The assumed load range NML extends from the no-load state DW that supports only the self-weight to the maximum load state DW+Lmax that supports the assumed maximum load and the self-weight. The preliminary load range PLL extends over a range wider than the assumed load range NML. The drive-wheel travel amount T20 extends over the entire assumed load range NML after operating in the preliminary load range PLL. Therefore, the drive wheel 20 can obtain sufficient ground contact load in the assumed load range NML.

[0063] The range in which all of the drive wheel travel amount T20, the rear wheel travel amount T40, and the front wheel travel amount T30 change is limited to a high load range HL that includes the maximum load state within the assumed load range NML. The front wheel travel amount T30 extends only over the high load range HL. The high load range HL is a part included in the assumed load range NML. In the assumed load range NML, the rear wheel suspension device 41 provides a longer travel amount (T40 > T30) than the front wheel suspension device 31. The rear wheel suspension device 41 provides a softer spring rate (k40 < k30) than the front wheel suspension device 31. As a result, the rear wheel suspension device 41 gives the vehicle body 10 a rearward tilt posture SQT.

[0064] FIG. 12 shows an example of the rearward tilt posture SQT. In FIG. 12, a load LD is mounted on the multi-wheel carrier 1. The load of the load LD activates at least both the drive wheel suspension device 21 and the rear wheel suspension device 41. As a result, the center of gravity axis GCX tilts so as to produce the rearward tilt posture SQT.

[0065] According to the multi-wheel carrier 1 described above, in the low load state, a preliminary load range PLL in which only the drive wheels 20 are in contact with the ground can be produced. Moreover, the drive wheel spring rate k20 acting on the drive wheels 20 is set to be smaller than the front wheel spring rate k30 and smaller than the rear wheel spring rate k40. As a result, the drive wheel suspension device 21 realizes the long travel (T20) of the drive wheels 20 with a soft spring rate (k20). Thereby, the ground contact load of the drive wheels 20 can be relatively increased, and the ground contact loads of the front wheels 30 and the rear wheels 40 can be decreased.

[0066] Furthermore, the front wheel travel T30 is set to allow movement of the front wheels 30 in the high load range HL, which includes the maximum load state of the expected load range NML. On the other hand, the rear wheel travel T40 allows movement of the rear wheels 40 in the expected load range NML, which includes the high load range HL. As a result, the front wheels 30 and rear wheels 40 impart a rearward-leaning attitude SQT to the vehicle body 10 in the expected load range NML. In other words, the front wheels 30 and rear wheels 40 create a front-up attitude in the expected load range NML. As a result, the load on the front wheels 30 is suppressed. In this way, the multi-wheel guided vehicle 1 disclosed herein can exhibit excellent step-overcoming performance without raising the center of gravity of the vehicle body.

[0067] Other embodiments The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and variations thereon by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including the meaning equivalent to the claims and all modifications within the scope.

[0068] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be written in a multiple dependent form, with the subsequent clause referring to the preceding clause as an alternative. Furthermore, some clauses may be written in a multiple dependent form, referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0069] (Technical thought 1) A car body (10), At least one drive wheel (20); a drive wheel suspension (21) that supports the drive wheel relative to the vehicle body so that the drive wheel is movable at least in the vertical direction, the drive wheel suspension (21) including a drive wheel suspension (24) that applies a drive wheel spring rate (k20) over a drive wheel travel amount (T20) of the drive wheel; At least one front wheel (30) disposed forward of the drive wheels in the traveling direction and driven by the rotation of the drive wheels; a front wheel suspension (31) that supports the front wheels relative to the vehicle body so that the front wheels are movable at least in the vertical direction, the front wheel suspension (31) including a front wheel suspension (34) that applies a front wheel spring rate (k30) over a front wheel travel amount (T30) of the front wheels; At least one rear wheel (40) disposed rearward of the drive wheels in the reverse direction and driven by the rotation of the drive wheels; a rear wheel suspension (41) that supports the rear wheels relative to the vehicle body so that the rear wheels are movable at least in the vertical direction, the rear wheel suspension (41) including a rear wheel suspension (44) that applies a rear wheel spring rate (k40) over a rear wheel travel amount (T40) of the rear wheels; The drive wheel spring rate (k20) is set to be smaller than the front wheel spring rate (k30) and smaller than the rear wheel spring rate (k40) (k20 < k30, k20 < k40). The drive wheel travel amount, the front wheel travel amount, and the rear wheel travel amount are set such that at least a part thereof overlaps in an assumed load range (NML) that extends from a no-load state (DW) that supports only the self-weight to a maximum load state (DW + Lmax) that supports the assumed maximum load and the self-weight. The drive wheel travel amount is set to generate a preliminary load range (PLL) in which only the drive wheels are in contact with the ground in a low load state that is smaller than the no-load state. The front wheel travel amount is set to allow movement of the front wheels in a high load range (HL) that includes the maximum load state of the assumed load range. The rear wheel travel amount is set to allow movement of the rear wheels in the assumed load range that includes the high load range, for a multi-wheel carrier.

[0070] (Technical idea 2) <关于技术思想2>[ The multi-wheel carrier according to Technical Idea 1, in which the rear wheel preload (PL40) preloaded on the rear wheel suspension is set to be smaller than the front wheel preload (PL30) preloaded on the front wheel suspension.

[0071] (Technical idea 3) <关于技术思想3>[ The multi-wheel carrier according to Technical Idea 1 or Technical Idea 2, in which the rear wheel spring rate (k40) is set to be smaller than the front wheel spring rate (k30) (k40 < k30).

[0072] (Technical idea 4) <关于技术思想4>[ The rear wheel travel amount (T40) extends over the entire assumed load range (NML). The front wheel travel amount (T30) extends over the high load range (HL). The multi-wheel carrier according to any one of Technical Ideas 1 to 3, in which the high load range (HL) is a part included in the assumed load range (NML).

[0073] (Technical Thought 5) A multi-wheeled transport vehicle described in any one of Technical Ideas 1 to 4, wherein, within the expected load range (NML), the rear wheel suspension device provides a longer travel distance and a softer spring rate than the front wheel suspension device, thereby giving the vehicle body a backward-leaning posture (SQT).

[0074] (Technical Thought 6) The multi-wheeled guided vehicle according to any one of Technical Ideas 1 to 5, wherein the preload range (PLL) is wider than the anticipated load range (NML).

[0075] (Technical Thought 7) A multi-wheeled transport vehicle described in any one of technical ideas 1 to 6, wherein the rear wheel travel (T40) extends across the entire expected load range (NML) and further extends across a portion of the preliminary load range (PLL).

[0076] (Technical Thought 8) A multi-wheeled transport vehicle described in any one of technical ideas 1 to 7, wherein the preliminary travel (TPL) of the drive wheel in the preliminary load range (PLL) is greater than the expected travel (TNM) of the drive wheel in the expected load range (NML).

[0077] (Technical Thought 9) The multi-wheeled guided vehicle according to any one of Technical Ideas 1 to 8, wherein the drive wheels have a diameter larger than the diameter of the front wheels and the diameter of the rear wheels.

[0078] (Technical Thought 10) The drive wheels are a right drive wheel (20R) disposed on the right side of the vehicle body; a left driving wheel (20L) disposed on the left side of the vehicle body; The drive wheel suspension device is a right driving wheel suspension (21R) that is journaled on at least one swing shaft (25Ra, 25Rb) extending in the front-rear direction of the vehicle body, extends toward the right in the width direction of the vehicle body, and includes at least one swing arm (23Ra, 23Rb) that supports the right driving wheel in an unsteerable manner; a left driving wheel suspension (21L) that is journaled on at least one swing shaft (25La, 25Lb) extending in the front-rear direction of the vehicle body, extends toward the left side in the width direction of the vehicle body, and includes at least one swing arm (23La, 23Lb) that supports the left driving wheel in an unsteerable manner; The front wheels are a right front wheel (30R) disposed on the right side of the vehicle body; a left front wheel (30L) disposed on the left side of the vehicle body; The front wheel suspension device is a right front wheel suspension (31R) including a right front swing arm (33R) that is journaled on a swing shaft (35R) extending in the width direction of the vehicle body, extends toward the front of the vehicle body, and supports the right front wheel via a right front turning base (32R) that enables free steering of the right front wheel; a left front wheel suspension (31L) including a left front swing arm (33L) that is journaled on a swing shaft (35L) extending in the width direction of the vehicle body, extends toward the front of the vehicle body, and supports the left front wheel via a left front turning base (32L) that enables free steering of the left front wheel; The rear wheel is a right rear wheel (40R) disposed on the right side of the vehicle body; a left rear wheel (40L) disposed on the left side of the vehicle body; The rear wheel suspension device is a right rear wheel suspension (41R) including a right rear swing arm (43R) journaled on a swing shaft (45R) extending in the width direction of the vehicle body, extending toward the rear of the vehicle body, and supporting the right rear wheel via a right rear turning base (42R) that enables free steering of the right rear wheel; a left rear wheel suspension (41L) including a left rear swing arm (43L) journaled on a swing shaft (45L) extending in the width direction of the vehicle body, extending toward the rear of the vehicle body, and supporting the left rear wheel via a left rear turning base (42L) that enables free steering of the left rear wheel; The multi-wheeled guided vehicle according to any one of Technical Ideas 1 to 9 further comprises a drive device (50) that steers using the rotational difference between the right drive wheel and the left drive wheel. [Explanation of symbols]

[0079] 1 multi-wheeled transport vehicle, 10 vehicle bodies, 20 driving wheel, 21 driving wheel suspension device, 22 Wheel hub, 23 Swing arm, 24 Drive wheel suspension, 25 Swing axis 30 front wheel, 31 front wheel suspension, 32 swivel base, 33 swing arm, 34 Drive wheel suspension, 35 Swing axis 40 Rear wheel 41 Rear wheel suspension; 42 swivel base, 43 swing arm, 44 Drive wheel suspension, 45 Swing axis 50 Drive unit, GND Running surface, GCX Center of gravity.

Claims

1. A vehicle body (10); At least one drive wheel (20); a drive wheel suspension (21) that supports the drive wheel relative to the vehicle body so that the drive wheel is movable at least in the vertical direction, the drive wheel suspension (24) including a drive wheel suspension that applies a drive wheel spring rate (k20) over a drive wheel travel amount (T20) of the drive wheel; At least one front wheel (30) disposed forward of the drive wheels in the direction of travel and driven by the rotation of the drive wheels; a front wheel suspension (31) that supports the front wheels relative to the vehicle body so that the front wheels are movable at least in the vertical direction, the front wheel suspension (31) including a front wheel suspension (34) that applies a front wheel spring rate (k30) over a front wheel travel amount (T30) of the front wheels; At least one rear wheel (40) disposed rearward of the drive wheels in the reverse direction and driven by the rotation of the drive wheels; a rear wheel suspension (41) that supports the rear wheel relative to the vehicle body so that the rear wheel is movable at least in the vertical direction, the rear wheel suspension (44) including a rear wheel suspension that applies a rear wheel spring rate (k40) over a rear wheel travel amount (T40) of the rear wheel; the drive wheel spring rate (k20) is set to be smaller than the front wheel spring rate (k30) and smaller than the rear wheel spring rate (k40) (k20<k30, k20<k40); the drive wheel travel amount, the front wheel travel amount, and the rear wheel travel amount are set to at least partially overlap within an assumed load range (NML) that extends from a no-load state (DW) in which only the vehicle's own weight is supported to a maximum load state (DW+Lmax) in which the vehicle supports both an assumed maximum load and its own weight, the drive wheel travel amount is set to generate a preload range (PLL) in which only the drive wheels contact the ground under a low load condition that is smaller than the no-load condition, the front wheel travel amount is set to allow movement of the front wheel in a high load range (HL) that includes the maximum load state of the expected load range, The rear wheel travel amount is set to allow movement of the rear wheels within the expected load range including the high load range.

2. 2. The multi-wheel guided vehicle according to claim 1, wherein a rear wheel preload (PL40) applied to the rear wheel suspension is set smaller than a front wheel preload (PL30) applied to the front wheel suspension.

3. 3. The multi-wheel guided vehicle according to claim 1, wherein the rear wheel spring rate (k40) is set smaller than the front wheel spring rate (k30) (k40<k30).

4. The rear wheel travel (T40) is spread over the entire expected load range (NML), the front wheel travel (T30) is spread across the high load range (HL), 3. The multi-wheel guided vehicle according to claim 1, wherein the high load range (HL) is a part of the expected load range (NML).

5. 3. A multi-wheeled guided vehicle as described in claim 1 or claim 2, wherein, within the expected load range (NML), the rear wheel suspension system provides a longer travel and a softer spring rate than the front wheel suspension system, thereby imparting a rearward leaning attitude (SQT) to the vehicle body.

6. 3. The multi-wheel guided vehicle according to claim 1, wherein the preload range (PLL) is wider than the expected load range (NML).

7. 3. The multi-wheel guided vehicle according to claim 1, wherein the rear wheel travel (T40) extends over the entire expected load range (NML) and also extends over a portion of the preload range (PLL).

8. A multi-wheeled guided vehicle as described in claim 1 or claim 2, wherein the preliminary travel (TPL) of the drive wheel in the preliminary load range (PLL) is greater than the expected travel (TNM) of the drive wheel in the expected load range (NML).

9. 3. The multi-wheel guided vehicle according to claim 1, wherein the drive wheels have a diameter (D20) larger than a diameter (D30) of the front wheels and a diameter (D40) of the rear wheels.

10. The drive wheels are a right drive wheel (20R) disposed on the right side of the vehicle body; A left driving wheel (20L) disposed on the left side of the vehicle body, The drive wheel suspension device is a right driving wheel suspension (21R) that is journaled on at least one swing shaft (25Ra, 25Rb) extending in the front-rear direction of the vehicle body, extends toward the right in the width direction of the vehicle body, and includes at least one swing arm (23Ra, 23Rb) that supports the right driving wheel in an unsteerable manner; a left driving wheel suspension (21L) that is journaled on at least one swing shaft (25La, 25Lb) extending in the front-rear direction of the vehicle body, extends toward the left side in the width direction of the vehicle body, and includes at least one swing arm (23La, 23Lb) that supports the left driving wheel in an unsteerable manner; The front wheels are a right front wheel (30R) disposed on the right side of the vehicle body; A left front wheel (30L) disposed on the left side of the vehicle body, The front wheel suspension device is a right front wheel suspension (31R) including a right front swing arm (33R) journaled on a swing shaft (35R) extending in the width direction of the vehicle body, extending forward of the vehicle body, and supporting the right front wheel via a right front turning base (32R) that enables free steering of the right front wheel; a left front wheel suspension (31L) including a left front swing arm (33L) journaled on a swing shaft (35L) extending in the width direction of the vehicle body, extending forward of the vehicle body, and supporting the left front wheel via a left front turning base (32L) that enables free steering of the left front wheel; The rear wheel is a right rear wheel (40R) disposed on the right side of the vehicle body; A left rear wheel (40L) disposed on the left side of the vehicle body, The rear wheel suspension device is a right rear wheel suspension (41R) including a right rear swing arm (43R) journaled on a swing shaft (45R) extending in the width direction of the vehicle body, extending toward the rear of the vehicle body, and supporting the right rear wheel via a right rear turning base (42R) that enables free steering of the right rear wheel; a left rear wheel suspension device (41L) including a left rear swing arm (43L) journaled on a swing shaft (45L) extending in the width direction of the vehicle body, extending toward the rear of the vehicle body, and supporting the left rear wheel via a left rear turning base (42L) that enables free steering of the left rear wheel; 3. The multi-wheeled guided vehicle according to claim 1, further comprising a drive unit (50) for steering the vehicle by means of a rotational difference between the right drive wheel and the left drive wheel.

Images