Vehicle suspension device

Abstract

This vehicle suspension device includes: a plate spring; a locking member to which one end of the plate spring is locked; and a holding member that holds the other end of the plate spring. The holding member includes: a roller that holds the other end of the plate spring and is capable of rotation following displacement of the other end of the plate spring; and a pressing member that faces the roller. The other end of the plate spring is provided between the roller and the pressing member. With regard to the thickness, the other end of the plate spring includes a portion in which, at an end on the side opposite the one end, the length in the thickness direction is greater than the thickness of other portions.

Description

Vehicle suspension system

[0001] The present invention relates to a suspension system for a vehicle.

[0002] Conventionally, suspension systems have been known that are provided on vehicles and have a buffering function to prevent vibrations caused by road surface irregularities from being transmitted to the vehicle body via the wheels, thereby improving the vehicle's ride comfort, steering stability, etc. Among such suspension systems, leaf spring type suspension systems are configured using leaf springs (see, for example, Patent Document 1).

[0003] The leaf spring described in Patent Document 1 has one end fixed to the vehicle body and the other end slidably supported via a slide seat. A load from the axle or the like is applied to the center of the longitudinal direction of the leaf spring, and the leaf spring is deformed by this load.

[0004] Japanese Unexamined Patent Publication No. 169307 / 1983

[0005] However, when the end of the leaf spring is held by a slide sheet, as in Patent Document 1, durability can decrease due to wear caused by friction between the slide sheet and the leaf spring, and abnormal noise can occur due to friction during sliding.

[0006] The present invention has been made in consideration of the above, and aims to provide a vehicle suspension device that can suppress a decrease in durability due to friction between the leaf spring and the retaining member and the generation of abnormal noise.

[0007] In order to solve the above-mentioned problems and achieve the object, the vehicle suspension device of the present invention is a suspension device comprising a leaf spring, a locking member to which one end of the leaf spring is locked, and a holding member to hold the other end of the leaf spring, wherein the holding member holds the other end of the leaf spring and has a roller that holds the other end of the leaf spring and is rotatable in response to displacement of the other end of the leaf spring, and a pressing member that faces the roller, the other end of the leaf spring being disposed between the roller and the pressing member, and the leaf spring has a portion at the end opposite to the one end side where the thickness of the other end is greater in the thickness direction than the thickness of the remaining portions.

[0008] In addition, in the vehicle suspension system according to the present invention, the leaf spring has a portion whose thickness is greater than the thickness of the other portion.

[0009] In addition, in the vehicle suspension system according to the present invention, the thickness of the leaf spring continuously increases toward the opposite side from the one end side.

[0010] In addition, in the vehicle suspension system according to the present invention, the other end of the leaf spring is sandwiched and held by the roller and the pressing member.

[0011] Furthermore, in the vehicle suspension system according to the present invention, the distance between the roller and the pressing member is equal to the minimum thickness of the leaf spring.

[0012] Furthermore, in the vehicle suspension system according to the present invention, the pressing member is a roller that is rotatable in response to displacement of the other end of the leaf spring.

[0013] According to the present invention, it is possible to suppress a decrease in durability due to friction between the leaf spring and the retaining member, and to suppress the generation of abnormal noise.

[0014] Fig. 1 is a diagram showing the configuration of a portion of a vehicle including a suspension system according to an embodiment of the present invention. Fig. 2 is a diagram for explaining the configuration of a leaf spring of the suspension system according to an embodiment of the present invention. Fig. 3 is a diagram showing the configuration of a roller of a suspension system according to a modified example of the present invention.

[0015] Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as "embodiments") will be described with reference to the accompanying drawings. Note that the drawings are schematic, and the relationship between the thickness and width of each part, the thickness ratio of each part, etc. may differ from the actual ones, and the drawings may also include parts with different dimensional relationships and ratios.

[0016] (Embodiment) Fig. 1 is a diagram showing the configuration of a portion of a vehicle including a suspension device according to one embodiment of the present invention. The suspension device 1 shown in Fig. 1 is mounted on the body of the vehicle and supports an axle 100 that supports a wheel 101. In Fig. 1, the left side is the front of the vehicle and the right side is the rear. The suspension device 1 includes a leaf spring 2, a locking member 3 to which one end of the leaf spring 2 is locked, and a holding member 4 that holds the other end of the leaf spring 2 so that it can move back and forth.

[0017] The locking member 3 and the holding member 4 are attached to the frame 110. Specifically, the locking member 3 is provided on a front mounting portion 120 that is fixed to the frame 110. The holding member 4 is provided on a rear mounting portion 130 that is fixed to the frame 110. The front mounting portion 120 and the rear mounting portion 130 are fixed to the frame 110 with fastening members such as screws. The locking member 3 is attached to the front mounting portion 120 by welding or the like. The holding member 4 is attached to the rear mounting portion 130 by welding or the like. The locking member 3 and the holding member 4 may be formed integrally with the front mounting portion 120 and the rear mounting portion 130, respectively.

[0018] An insertion hole (not shown) is formed in the longitudinal center of the leaf spring 2 and in the center of the washer 140. The leaf spring 2 and the washer 140 form a leaf spring assembly that is fixed by fastening a center bolt 140a inserted through each insertion hole to a nut 140b. The leaf spring assembly is fixed to a housing 160 by a U-bolt 150. The housing 160 is fixed to the axle 100.

[0019] 2 is a diagram illustrating the configuration of a leaf spring of a suspension system according to one embodiment of the present invention. The leaf spring 2 has a main body 20 formed by bending one end of a strip-shaped member, a hook-shaped first end 21 provided on one end of the main body 20, and a second end 22 provided on the other end of the main body 20. The leaf spring 2 is formed using a metal material (e.g., spring steel), a resin material, or fiber-reinforced plastics (FRP).

[0020] The axle 100 is disposed below the main body 20 at the center in the longitudinal direction of the main body 20 .

[0021] The first end 21 is locked by being wrapped around the locking member 3 .

[0022] The thickness of the second end 22 increases toward the end opposite the end connected to the main body 20 (one end). For example, a gradual change in spring characteristics can be achieved by continuously increasing the thickness. A gradual change in spring characteristics can be achieved by gradually increasing the thickness. A more reliable retention of the leaf spring from the retaining member 4 can be achieved by suddenly increasing the thickness by changing the thickness of a portion of the leaf spring. The thickness can be appropriately set depending on the characteristics and function. Here, the thickness refers to the length, at the position where the thickness is measured, extending from the first end 21 to the second end 22 in the longitudinal direction (e.g., the left-right direction in FIG. 2 ) and in the direction perpendicular to the direction parallel to the surface of the leaf spring 2 that contacts the washer 140 or the retaining member 4 (the direction perpendicular to the plane of FIG. 2 ) (e.g., the up-down direction in FIG. 2 , corresponding to the thickness direction). Furthermore, the retention can be achieved by bending or winding the end portion. In this way, the second end 22 of the leaf spring 2 only needs to have a portion whose length in the thickness direction is greater than the plate thickness of the remaining portion. The "other portion" here refers to at least a portion of the first end 21, the main body 20, and the second end 22 on the main body 20 side, where the plate thickness is controlled to approximately the distance (gap) between the first roller 41 and the second roller 42 described below. For example, the second end 22 has a portion whose length in the thickness direction at the end opposite the side connected to the main body 20 (one end side) is greater than the plate thickness of the portion whose plate thickness is approximately the distance (gap) between the first roller 41 and the second roller 42.

[0023] The holding member 4 is made up of a pair of rollers (a first roller 41 and a second roller 42).

[0024] The first roller 41 has a first shaft portion 41a connected to the rear mounting portion 130 and a first rotating portion 41b that is rotatable relative to the first shaft portion 41a. The first rotating portion 41b is connected to the first shaft portion 41a via, for example, a bearing, and rotates around the central axis N1 of the first shaft portion 41a.

[0025] The second roller 42 has a second shaft portion 42a connected to the rear mounting portion 130 and a second rotating portion 42b that is rotatable relative to the second shaft portion 42a. The second rotating portion 42b is connected to the second shaft portion 42a via a bearing, for example, and rotates around the central axis N2 of the second shaft portion 42a.

[0026] The distance (gap) between the first roller 41 and the second roller 42 is equal to or slightly narrower than the minimum thickness of the leaf spring 2. If the rollers are rigid, this gap is preferably equal to the leaf thickness (here, the minimum thickness). If at least a portion of the rollers is elastic, this gap is preferably narrower than the leaf thickness. Therefore, when the leaf spring 2 is disposed between the rollers, the first roller 41 and the second roller 42 each contact and grip the leaf spring 2. Furthermore, if the contact position of the leaf spring 2 with the holding member 4 moves toward the end of the second end 22 opposite the main body 20, the leaf spring 2 becomes thicker, thereby increasing resistance to displacement of the leaf spring 2. Note that the term "equal" here includes manufacturing errors, etc. Furthermore, as long as the leaf spring 2 can be held, the distance (gap) between the first roller 41 and the second roller 42 is not limited to the minimum thickness of the leaf spring 2 and can be, for example, less than the maximum thickness.

[0027] The first shaft portion 41a and the second shaft portion 42a are formed using, for example, a metal material. The first rotating portion 41b and the second rotating portion 42b are formed using, for example, a metal material, a resin material, rubber, or the like. By forming at least one of the rotating portions using an elastic material such as rubber or resin, a damping effect can be obtained. Furthermore, the damping effect can be adjusted by adjusting the distance between the first shaft portion 41a and the second shaft portion 42a. The first roller 41 and the second roller 42 face each other and correspond to a roller and a pressing member between which the end of the leaf spring 2 is provided.

[0028] The leaf spring 2 deforms in response to vibrations of the axle 100 due to road surface irregularities, etc. (See the dashed line in FIG. 2 ). The second end 22 is held by the retaining member 4 by being sandwiched between the first roller 41 and the second roller 42. When the second end 22 is displaced relative to the retaining member 4 due to deformation of the leaf spring 2, the length between the locking member 3 of the leaf spring 2 and the retaining member 4, i.e., the effective span of the leaf spring 2, changes, thereby changing the load characteristics of the leaf spring 2. In addition, at this time, the first rotating portion 41 b and the second rotating portion 42 b rotate in response to the displacement of the second end 22, thereby suppressing friction with the second end 22.

[0029] In the embodiment of the present invention described above, one end of the leaf spring 2, which deforms in response to vibration of the axle 100, is engaged with the vehicle body (here, frame 110), and the other end is gripped by the first roller 41 and the second roller 42, and the first roller 41 and the second roller 42 rotate in response to displacement of the end of the other end due to deformation. According to this embodiment, the rotation of the rollers suppresses the generation of friction between the leaf spring 2 and the retaining member 4, making it possible to suppress a decrease in durability and the generation of abnormal noise due to friction between the leaf spring and the retaining member.

[0030] Here, when the end of the leaf spring 2 is held by a slide seat, if the leaf spring 2 breaks forward of the axle, the body of the leaf spring 2 rotates around the rear end connection portion, causing the axle to move closer to the vehicle body, resulting in a significant drop in vehicle height. In contrast, when the leaf spring 2 is sandwiched between the first roller 41 and the second roller 42 located rearward of the first roller 41 on the vehicle body, as in this embodiment, even if the leaf spring 2 breaks forward, a repulsive force is generated on the rear side due to the sandwiching, so a significant drop in vehicle height can be prevented.

[0031] In this embodiment, the thickness of the second end 22 is changed so that the load that the leaf spring 2 applies to each roller increases as the holding position by the holding member 4 moves away from the main body 20 side of the second end 22. According to this embodiment, it is possible to adjust the change in the effective span by setting the thickness of the leaf spring 2. Furthermore, by making the thickness of the end of the second end 22 opposite the main body 20 side greater than the distance between the rollers, it is possible to reliably prevent the leaf spring 2 from slipping out of the holding member 4.

[0032] Furthermore, according to this embodiment, by holding the leaf spring 2 with rollers, it is possible to give the leaf spring 2 nonlinear characteristics with a simpler structure than conventional leaf springs in which a main spring and a sub-spring are stacked.

[0033] Furthermore, in this embodiment, the thickness of the rotating portion relative to the rotating shaft can be made uniform, making the resistance that the leaf spring receives from the rollers uniform, thereby improving vibration-proofing properties and durability.

[0034] (Modification) Next, a modification of the embodiment of the present invention will be described with reference to Fig. 3. Fig. 3 is a diagram showing the configuration of the rollers of a suspension device according to a modification of the present invention. The suspension device according to the modification includes a roller 43 instead of the first roller 41 and the second roller 42 of the holding member 4. The other components are configured the same as in the embodiment, and therefore description thereof will be omitted.

[0035] The roller 43 has a shaft portion 43a connected to the rear mounting portion 130 and a rotating portion 43b that is rotatable relative to the shaft portion 43a. The rotating portion 43b is connected to the shaft portion 43a via, for example, a bearing, and rotates around the central axis N3 of the shaft portion 43a.

[0036] The rotating portion 43b has a hollow cylindrical main body 431 through which the shaft 43a is inserted, a first protrusion 432 provided at one end of the main body 431 and protruding from the outer circumferential surface of the main body 431, and a second protrusion 433 provided at the other end of the main body 431 and protruding from the outer circumferential surface of the main body 431. The first protrusion 432 and the second protrusion 433 protrude to an extent that they do not interfere with the protrusions of the other roller in the pair. Note that these protrusions only need to protrude in a direction intersecting the direction of the central axis N3. The second end 22 of the leaf spring 2 passes between the first protrusion 432 and the second protrusion 433.

[0037] In the present modified example described above, similarly to the embodiment, one end of the leaf spring 2 that deforms in response to vibration of the axle 100 is engaged with the vehicle body (here, frame 110) and the other end is gripped by two rollers 43, and the rollers 43 rotate in response to displacement of the end of the other end due to deformation. According to this modified example, the rotation of the rollers 43 suppresses the generation of friction between the leaf spring 2 and the retaining member 4, making it possible to suppress a decrease in durability and the generation of abnormal noise due to friction between the leaf spring and the retaining member.

[0038] Furthermore, according to the modified example, the leaf spring 2 passes between the first protrusion 432 and the second protrusion 433, which prevents the leaf spring 2 from being displaced in the direction of the central axis N3 and falling off. As a result, in this modified example, it is possible to more reliably prevent the leaf spring 2 from being detached from the holding member compared to the configuration of the embodiment.

[0039] In a modified example, one roller may be roller 43 and the other roller may be first roller 41 or second roller 42 .

[0040] In a modified example, a protrusion may be provided on only one end of the roller 43, and the protrusions of the pair of rollers may be positioned on opposite sides to prevent the leaf spring 2 from coming off.

[0041] In the modified example, the protrusion is provided at the end of the roller 43 in the direction of the central axis N3, but it does not have to be at the end as long as it is located in a position where the roller can grip the leaf spring 2 while suppressing displacement of the leaf spring 2 in the direction of the central axis N3.

[0042] Up to this point, the embodiments for carrying out the present invention have been described, but the present invention should not be limited to only the above-described embodiments. In the above-described embodiments and modifications, the axle 100 and the leaf spring 2 are connected via a U-bolt 150. However, a configuration without a U-bolt, for example, in which the axle 100 and the leaf spring 2 are directly connected, may also be used. Furthermore, in the above-described embodiments and modifications, the leaf spring 2 is arranged above the axle 100, but the leaf spring 2 may also be arranged below the axle 100.

[0043] In the embodiment and the modified example, a recess may be formed in the end face of the second end 22 of the leaf spring 2 to adjust the rigidity of the second end 22 .

[0044] In addition, in the embodiments and variants, a rotary table supporting the first roller 41 and the second roller 42 may be provided on the rear mounting portion 130, and the first roller 41 and the second roller 42 may rotate (revolve) around the rotation axis of the rotary table.

[0045] In the embodiment and the modified example, a holding member 4 may be provided in place of the locking member 3, and both ends of the leaf spring 2 may be gripped by rollers.

[0046] In the embodiment and modified examples, one of the rollers may be a non-rotating holding member (corresponding to a pressing member). For example, the second roller 42 may be replaced with a holding member, and the leaf spring 2 may be held by the first roller 41 and the pressing member. In this case, the surface of the holding member that comes into contact with the leaf spring 2 may be curved, or a recess may be formed on the surface that comes into contact with the leaf spring 2.

[0047] In the embodiment and the modified example, the first roller 41 and the second roller 42 may be supported by shackles.

[0048] As such, the present invention may include various embodiments not described here, and various design changes may be made within the scope of the technical idea specified by the claims.

[0049] As described above, the vehicle suspension device according to the present invention is suitable for suppressing a decrease in durability due to friction between the leaf spring and the retaining member, and suppressing the generation of abnormal noise.

[0050] REFERENCE SIGNS LIST 1 Suspension device 2 Leaf spring 3 Locking member 4 Holding member 41 First roller 42 Second roller 43 Roller 41a First shaft portion 41b First rotating portion 42a Second shaft portion 42b Second rotating portion 43a Shaft portion 43b Rotating portion 100 Axle 101 Wheel 110 Frame 120 Front mounting portion 130 Rear mounting portion 140 Washer 150 U-bolt 160 Housing 431 Main body portion 432 First protrusion portion 433 Second protrusion portion

Claims

1. A suspension device comprising: a leaf spring; a locking member to which one end of the leaf spring is locked; and a retaining member that holds the other end of the leaf spring, wherein the retaining member has a roller that holds the other end of the leaf spring and is rotatable following the displacement of the other end of the leaf spring; and a pressing member that faces the roller, wherein the other end of the leaf spring is provided between the roller and the pressing member, and wherein the leaf spring has, at an end opposite to the one end side, a portion whose length in the thickness direction is greater than the plate thickness of the remaining portions.

2. The vehicle suspension system according to claim 1, wherein the leaf spring has a portion whose thickness is greater than the remaining portion.

3. The vehicle suspension device according to claim 2, wherein the leaf spring has a thickness that increases continuously from the one end toward the opposite side.

4. The vehicle suspension system according to claim 1, wherein the other end of the leaf spring is sandwiched and held by the roller and the pressing member.

5. The vehicle suspension system according to claim 4, wherein the distance between the roller and the pressing member is equal to the minimum thickness of the leaf spring.

6. The vehicle suspension system according to claim 1, wherein the pressing member is a roller that is rotatable in response to the displacement of the other end of the leaf spring.

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