Suspension device

Abstract

To provide a suspension device capable of properly absorbing vertical movement of wheels even when a traveling surface is uneven and capable of suppressing vehicle body inclination to enable stable traveling.SOLUTION: A suspension device comprises: a vehicle body capable of traveling; a first strut and a second strut which are supported movably in a vertical direction with respect to the vehicle body and arranged at an interval; a first wheel and a second wheel which are respectively provided at lower ends of the first strut and the second strut; and a first biasing member and a second biasing member which bias the first strut and the second strut downward. The first biasing member biases the first strut and the second strut downward with respect to the vehicle body up to a maximum projection length L projecting downward, and the second biasing member biases these downward beyond the projection length L.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a suspension device. [Background technology]

[0002] 2. Description of the Related Art Generally, vehicles such as two-wheeled and four-wheeled vehicles are provided with a suspension device to absorb vibrations of the vehicle caused by unevenness in the road surface while the vehicle is traveling. A known example of this type of suspension device is disclosed in Patent Document 1. The suspension device described in Patent Document 1 is a suspension device provided on a brush cutter, which has a motor as a power source and wheels that are driven to rotate by the motor, attached to the lower part of a support frame that makes up the vehicle body. The wheels are supported on the vehicle body so that they can move up and down freely, and when the wheels move up and down due to unevenness in the road surface, the up and down movement is absorbed by a coil spring interposed between the vehicle body and a member that supports the wheels. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2001-507242 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in places where lawnmowers are used, there are often deep, narrow depressions that may have been dug by small animals, and if a wheel falls into a deep depression that exceeds the range of motion of the suspension device, the suspension device may stop functioning, causing the vehicle body to tilt and resulting in unstable driving.

[0005] The problem to be solved by the present invention is to provide a suspension device that can appropriately absorb the vertical movement of the wheels even when the traveling surface is uneven, suppress the tilting of the vehicle body, and ensure stable traveling. [Means for solving the problem]

[0006] The suspension device of the present invention comprises a vehicle body that can travel freely, a first support pillar and a second support pillar that are supported so as to be movable in the vertical direction relative to the vehicle body and are spaced apart, a first wheel and a second wheel that are respectively attached to the lower ends of the first support pillar and the second support pillar, and a first biasing member and a second biasing member that bias the first support pillar and the second support pillar downward, wherein the first biasing member biases the first support pillar and the second support pillar downward to a maximum extent of a projection length L that the first support pillar and the second support pillar respectively project downward relative to the vehicle body, and the second biasing member biases the first support pillar and the second support pillar downward beyond the projection length L. [Effects of the Invention]

[0007] According to the present invention, even if the traveling surface is uneven, the vertical movement of the wheels can be appropriately absorbed, and tilting of the vehicle body can be suppressed, allowing for stable traveling. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B are diagrams showing the basic configuration of a suspension device shown as a first embodiment of the present invention, in which (a) is a side view of the suspension device and (b) is a front view of the same. [Figure 2] 4 is an explanatory diagram illustrating the operation of the suspension device. FIG. [Figure 3] 4 is an explanatory diagram illustrating the operation of the suspension device. FIG. [Figure 4] 10 is a diagram showing the relationship between the biasing force and stroke of the suspension device and a suspension device using only a compression spring. FIG. [Figure 5] FIG. 4 is an explanatory diagram of the basic configuration of a grass mower equipped with the suspension device shown as a second embodiment of the present invention, and is a side view of the suspension device. [Figure 6] 10A and 10B are diagrams showing modified examples of the method of attaching the second biasing member of the suspension device according to the present invention, where (a) is an explanatory diagram of a first modified example, and (b) is an explanatory diagram of a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] FIG. 1(a) is a side view of a main part of a suspension device 1 of the present invention, and FIG. 1(b) is a front view thereof. In this figure, a first support pillar 4a and a second support pillar 4b are supported on a support frame 2 that constitutes part of the vehicle so as to be movable up and down, spaced apart in the fore-and-aft direction of the support frame 2. A first wheel 3a and a second wheel 3b are rotatably supported on the lower ends of the support pillars 4a and 4b, respectively. The front and rear support columns 4a, 4b are movable relative to the support frame 2 only in the vertical direction by guide members (not shown).

[0011] The front and rear wheels 3a, 3b and the elements supporting these wheels 3a, 3b shown in FIG. 1(a) form a set of wheel parts, and as shown in FIG. 1(b), two sets of these wheel structures 13 are provided at an interval in the width direction of the vehicle, so that the vehicle is configured as a four-wheeled vehicle.

[0012] The support pillar 4a is biased downward by a compression spring 5 that constitutes a first biasing member and a constant force spring 6 that constitutes a second biasing member. The compression spring 5 utilizes the force of a compressed and deformed spring returning to its original shape. It is interposed between the lower end of the support frame 2 and an engaging member 7 fixed to the support column 4a below the support frame 2, and in the state shown in Figure 1(a), it urges the support column 4a downward relative to the support frame 2.

[0013] The support frame 2 is provided with fixed plates 9, 9, 9 as components that constitute part of the support frame 2. The fixed plates 9, 9, 9 are fixed in a U-shape by pins 8, 8. A constant force spring 6 is interposed between the fixed plate 9 located at the top and the upper end of the support column 4a.

[0014] The constant force spring 6 has a long leaf spring 12 bent at a fixed curvature and stored in a wound state inside a drum 11, and utilizes the force of the leaf spring 12 trying to return to its original shape when pulled out. The drum 11, which forms the first end of the constant force spring 6, is fixed to the upper end of the support column 4a, and the pulled-out end of the leaf spring 12, which forms the second end, is fixed to the support frame 2. With this configuration, the constant force spring 6 urges the support column 4a downward relative to the support frame 2 in the state shown in Figure 1(a).

[0015] Like the support column 4a, the support column 4b is biased downward by a compression spring 5 and a constant force spring 6. The configuration for biasing the support column 4b downward is the same as the configuration for the support column 4a. The wheels 3a, 3b are driven to rotate by a drive source (not shown), and the vehicle can travel in the forward and backward directions on the travel surface G by appropriately operating a control device.

[0016] In the above configuration, the members including the compression spring 5, constant force spring 6, and struts 4a and 4b constitute a suspension device 1 that absorbs vibrations to the vehicle body caused by the up and down movement of the wheels 3a and 3b when the vehicle is running.

[0017] (Action and effect) 1 shows the state when the vehicle is positioned on a flat running surface G, and in this state, the compression spring 5 and the constant force spring 6 both apply a constant biasing force to the wheels 3a, 3b via the supports 4a, 4b toward the running surface G. The compression spring 5 is compressed by a certain dimension due to the load of the vehicle, and the leaf spring 12 of the constant force spring 6 is in a state where it is extended by a certain dimension due to the load of the vehicle. In this state, the suspension device 1 is in a state in which the biasing force of each biasing member is balanced with the weight of the vehicle.

[0018] FIG. 2 shows a state in which the front wheel 3a falls into a deep depression while the vehicle is running, and FIG. 3 shows a state in which the front wheel 3a runs over a bump or other protruding surface while the vehicle is running.

[0019] In the state shown in Figure 2, when the wheel 3a falls into the depression, the support 4a of the fallen wheel 3a moves downward, so that the compression spring 5 of the fallen wheel 3a returns to its natural length, the biasing force against the running surface G disappears, and the biasing force of the compression spring 5 becomes 0 (N). On the other hand, when the wheel 3a falls into the recess, the support 4a of the fallen wheel 3a moves downward, causing the leaf spring 12 of the constant force spring 6 to rewind a certain distance within the drum 11, but the biasing force is maintained, and the wheel 3a is biased against the running surface G with a certain pressure via the support 4a.

[0020] Here, if the protruding length of the first support 4a just before the compression spring 5 reaches its natural length is defined as protruding length L, protruding length L is the maximum length at which the compression spring 5 can urge the first support 4a downward, and when this first support 4a exceeds protruding length L, the downward urging force of the compression spring 5 disappears. On the other hand, the constant force spring 6 continues to urge the first support column 4a downward even after the urging force of the compression spring 5 has disappeared.

[0021] Furthermore, even when other wheels 3 try to lift off the running surface G, the compression spring 5 reaches its natural length and exceeds the protruding length L, causing the biasing force to disappear, but since the constant force spring 6 is set to work, tilting of the vehicle body can be suppressed.

[0022] When one of the wheels 3a collapses, the entire vehicle tilts toward the collapsing wheel 3a, causing the wheel 3 diagonal to the collapsing wheel 3a to move in a lifted position. At that time, the compression spring 5 in the wheel 3 diagonal to the collapsing wheel 3a reaches its natural length, the biasing force against the running surface G disappears, and the biasing force of the compression spring 5 becomes 0 (N), but the constant force spring 6 can bias the wheel 3 diagonal to the collapsing wheel 3a with a constant pressure against the running surface G. Therefore, the lifting of the wheel 3 diagonal to the collapsing wheel 3a can be suppressed, and the tilting of the vehicle body can be suppressed.

[0023] In the state shown in FIG. 3, when the wheel 3a runs over a bump, the support 4a of the running wheel 3a moves upward, compressing the compression spring 5 that biases the running wheel 3a, generating a force that tries to return to its original state, and increasing the biasing force against the running surface G. On the other hand, when the wheel 3a rides over a protruding surface, the support 4a of the wheel 3a that rides over moves upward, causing the leaf spring 12 of the constant force spring 6 to be further extended and apply a constant pressure to the riding surface G.

[0024] When one of the wheels 3a climbs over a bump, the entire vehicle tilts toward the wheel 3 diagonally opposite the climbing wheel 3a, causing the wheel 3 opposite the climbing wheel 3a and the wheels 3b before and after the climbing wheel 3a to move in a lifted position. At that time, the compression springs 5 ​​in the wheel 3 opposite the climbing wheel 3a and the wheels 3b before and after the climbing wheel 3a reach their natural lengths, and the biasing force against the running surface G disappears, so the biasing force of the compression springs 5 ​​becomes 0 (N), but the constant force springs 6 can bias the wheels 3 opposite the climbing wheel 3a and the wheels 3b before and after the climbing wheel 3a with a constant pressure against the running surface G. Therefore, the wheel 3 opposite the climbing wheel 3a and the wheels 3b before and after the climbing wheel 3a can be prevented from lifting, and the tilt of the vehicle body can be prevented.

[0025] FIG. 4 is a diagram showing the relationship between the biasing force and the stroke when the suspension device 1 of the present invention and the suspension device 1 of the present invention are provided with only a compression spring by removing the constant force spring.

[0026] As described above, when the vehicle is running and the front wheel 3a falls into a deep depression, the wheel 3a protrudes downward beyond the natural length of the compression spring 5, causing the compression spring 5 to no longer act, and the biasing force against the running surface G becomes 0 (N). However, the constant force spring 6 always generates a constant biasing force against the running surface G.

[0027] As described above, the suspension device 1 of the present invention can provide a suspension device 1 that can appropriately absorb the up and down movement of the wheels 3 even if the running surface G is uneven, suppress the tilting of the vehicle body, and ensure stable running.

[0028] In the above embodiment, it has been described that the drum 11 constituting the first end is fixed to the upper end of the support pillar 4a, and the drawn-out end of the leaf spring 12 constituting the second end is fixed to the support frame 2. However, instead of this configuration, the first end may be fixed to the support frame 2, and the second end may be fixed to the upper end of the support pillar 4a. Furthermore, in the above embodiment, a four-wheel vehicle has been described, but it may also be configured as a two-wheel vehicle having a front wheel and a rear wheel as shown in FIG. 1(a).

[0029] (Second embodiment) 5 shows a second embodiment of the present invention, which differs from the first embodiment in that a grass cutting device 21 is mounted on a vehicle equipped with the suspension device 1 described above.

[0030] The grass cutting device 21 includes a cutter support mechanism 23 including links 22a, 22b, 22c, and 22d, wheels 24a and 24b provided on link 22c of the cutter support mechanism 23, and a cutter 25 supported on link 22a of the cutter support mechanism 23.

[0031] One end of a rod 26 is rotatably attached to link 22b by a pin 27, and the other end of rod 26 is slidably supported within an elongated hole 28 of link 22c. By fixing the other end of rod 26 at an appropriate position within elongated hole 28, links 22a, 22b, 22c, and 22d can be fixed in a predetermined shape.

[0032] Figure 5 shows a side view of the grass cutting device, and only shows one of the links 22a, 22b, 22c, 22d of the cutter support mechanism 23 and the wheels 24a, 24b, but just as it was explained in Figures 1(a) and 1(b) that the vehicle is a four-wheeled vehicle, the grass cutting device 21 is also equipped with the other link 22 of the cutter support mechanism 23 and the wheels 24, and is configured as a four-wheeled vehicle.

[0033] The mowing device 21 is attached to the support frame 2 of the vehicle via a support pole 29. In this case, the support pole 29 is attached to the support frame 2 so as to be movable up and down within a certain range. The support column 29 is connected to the link 22a of the cutter support mechanism 23 by a universal joint.

[0034] With the above-described configuration, the grass cutting device 21 is movable up and down within a certain range relative to the ground on which the vehicle travels, and can move up and down depending on the shape of the ground. In this second embodiment, when the vehicle is driven to mow the grass using the grass-cutting device 21, first, the position of the pin 30 provided at the lower end of the rod body 26 is fixed to an appropriate position within the long hole 28, and the height of the cutter 25 relative to the wheels 24a, 24b is fixed to a fixed position. Then, the vehicle is driven, the mowing device 21 is started, and the cutter 25 mows the grass, but at this time, the mowing device 21 moves up and down according to the shape of the ground, so the height of the mowing device 21 can always be kept at a fixed position. Furthermore, since the support 29 and the link 22a of the cutter support mechanism 23 are connected by a universal joint, even if the ground is uneven, the grass cutting device 21 can freely change its position in the roll and pitch directions, and the cutter 25 can be maintained in an appropriate position while cutting grass.

[0035] In the second embodiment, the effect of the suspension device 1 described above can also be obtained, so that even if the running surface is uneven, the up and down movement of the wheels 3 can be appropriately absorbed, and tilting of the vehicle body can be suppressed, allowing for stable running, so that grass cutting work can also be performed stably.

[0036] (Variation) Figures 6(a) and 6(b) show modified examples of the suspension device of the first embodiment shown in Figures 1(a) and 1(b). Below, we will first explain the first modified example in Figure 6(a), focusing on the differences from Figures 1(a) and 1(b).

[0037] In FIG. 6(a), a support column 4a is supported on a support frame 2 so as to be movable up and down, and a wheel 3a is provided at the lower end of the support column 4a. The drum 11 constituting the first end of the constant force spring 6 is fixed to the support frame 2, and the end of the leaf spring 12 drawn out from the drum 11 constituting the second end is fixed to the upper end of the support 4a. With this configuration, the constant force spring 6 biases the support column 4a downward relative to the support frame 2 in the state shown in FIG. 6(a).

[0038] 6(b), a support column 4a is supported on the support frame 2 so as to be movable up and down, and a wheel 3a is provided at the lower end of the support column 4a. A pulley 41 is provided near the support column 4a. The drum 11 constituting the first end of the constant force spring 6 is fixed to the support frame 2, and the end of the leaf spring 12 pulled out from the drum 11 constituting the second end is fixed to the upper end of the support 4a via a pulley 41. With this configuration, the constant force spring 6 biases the support column 4a downward relative to the support frame 2 in the state shown in FIG. 6(b).

[0039] In the configuration shown in FIGS. 6( a ) and 6 ( b ) above, the column 4 a can be biased downward relative to the support frame 2 by the constant force spring 6 . 6(a) and 6(b) show modified examples of the mounting state of the constant force spring 6, but the present invention is not limited to these modified examples, and any configuration that biases the support column 4a downward is sufficient. [Explanation of symbols]

[0040] 1. Suspension device 2 Support Frame 3 wheels 3a First Wheel 3b Second Wheel 4a First Pillar 4b Second Pillar 5 compression springs 6 Constant Force Spring 7 Engagement member 11 Drums 12 Leaf spring 13 Wheel structure 21 Grass-cutting equipment 22 Links 22a Link 22b Link 22c Link 22d Link 23 Cutter support mechanism 24 wheels 24a wheels 24b wheels 25 Cutter 26 rod 29 Post G Running surface L protrusion length

Claims

1. A body that can move freely, a first support pillar and a second support pillar that are supported so as to be movable in the up and down direction relative to the vehicle body and are provided at a distance from each other; a first wheel and a second wheel provided at the lower ends of the first support column and the second support column, respectively; a first biasing member and a second biasing member that bias the first support column and the second support column downward, the first biasing member biases the first support pillar and the second support pillar downward with a maximum downward projection length L relative to the vehicle body, The second biasing member biases downward beyond the projection length L of the suspension device.

2. the first biasing member is a compression spring that utilizes the force of a compressed and deformed spring returning to its original shape, and the compression spring is interposed between a support frame that constitutes the vehicle body and an engaging member that is provided on a portion of the support pillar that is located below the support frame; 2. The suspension device of claim 1, wherein the second biasing member is a constant force spring that uses a force of the extended leaf spring to return to its original shape when the drum is defined as a first end and a tip of the leaf spring as a second end, and wherein either the first end or the second end is fixed to an upper end of the support column located above the support frame, and the other of the first end or the second end is fixed to the support frame.

3. 3. The suspension device according to claim 1 or 2, wherein the first wheel and the second wheel, together with the first support pillar and the second support pillar, form a wheel assembly, and two sets of the wheel assembly are provided at an interval in the width direction of the vehicle body, and the vehicle body is configured as a four-wheeled vehicle.

Images