JP4711426B2 - Rubber spring device for articulated dump truck - Google Patents

Description

  The present invention relates to a rubber spring device that receives a compressive load and a tensile load, and more particularly to a rubber spring device that can be used as a suspension for an off-road truck such as an articulated dump truck.

  Conventionally, as a rubber spring device used as a suspension for an off-road truck, a force transmission element described in Patent Document 1 and an elastomer mounting tool described in Patent Document 2 have been proposed. The force transmission element described in Patent Document 1 is a conventional example 1 of the present invention, and FIG. 9 is a longitudinal sectional view of the force transmission element.

  The force transmission element 50 shown in FIG. 9 is configured to be attached between one end of a bogie pivot beam pivotally attached to a vehicle frame and the axle. When no load is applied to the force transmission element 50, the pair of end plates 51 and 52 are in a parallel state. Further, a hardened solid cylindrical rubber body 53 is disposed between the pair of end plates 51 and 52, and the cylindrical rubber body 53 includes a plurality of flat plates arranged in parallel at equal intervals. Reinforced by a metal ring 54. The metal ring 54 is embedded in the cylindrical rubber body 53.

  A pair of U-shaped latches 55 are fixed to the end plates 51 and 52, respectively, and the pair of latches 55 are flexibly connected by an annular chain link 56. A pair of latches 55 and an annular chain link 56 constitute a mechanical coupling device. The mechanical coupling device is coupled in the cylindrical rubber body 53.

  FIG. 10 shows a partial vertical cross-sectional view of an elastomer fixture as the conventional example 2 of the present invention. The elastomer mounting tool 60 shown in FIG. 10 is configured to be mounted between the vehicle's Askul structure and one end of a bogie pivot beam that is rotatably provided in the vehicle frame.

  The elastomer fitting 60 includes two metal end plates 61 and 62 each having a square shape, and an intermediate elastomer body 63 that receives a compressive load when the metal end plates 61 and 62 approach each other. The elastomer main body 63 is formed in a tubular shape as a whole and has an annular cross-sectional shape.

  The elastomer main body 63 is reinforced by metal reinforcing rings 66 to 74, and the metal reinforcing rings 66 to 74 are divided into two groups. These metal reinforcing rings 66 to 74 are bonded to the natural rubber while being embedded in natural rubber which is an elastomer material constituting the elastomer main body 63. Each reinforcement ring 66-74 is comprised of a flat annular steel disk and lies in a plane that crosses the longitudinal axis of the elastomer fixture 60.

  The first group includes six metal reinforcement rings 66 to 71, and each metal reinforcement ring 66 to 71 is provided in a state of being spaced from each other in the axial direction. Further, each metal reinforcing ring 66 to 71 has a length dimension in each radial direction so as to have a substantially similar shape corresponding to the local radial spreading shape in the axial direction of the elastomer body 63. Have.

  Further, each of the metal reinforcing rings 66 to 71 has the same inner diameter 75 and is exposed to the central chamber 76 formed in the tubular elastomer body 63. The outer peripheral edge 77 of each metal reinforcing ring 66 to 71 is located immediately below the outer surface 78 of the elastomer body 63. The elastomer main body 63 is configured so that the region as a whole has a smooth outline, and the presence of the embedded metal reinforcing rings 66 to 71 is not known.

  The metal reinforcing rings 72 to 74 of the second group have the same outer peripheral diameter, and the outer peripheral diameter is configured to be smaller than the outer peripheral diameter of the metal reinforcing rings 66 to 71 in the first group. Further, the metal reinforcing rings 72 to 74 are arranged at equal intervals in the axial direction.

  On the other hand, the metal reinforcing rings 66 to 71 of the first group are arranged at unequal intervals in the axial direction. In the first group, the metal reinforcing rings 68 to 70 having the largest outer diameter are arranged at the tightest intervals, and the intervals between the metal reinforcing rings 71 and 72 are the metal reinforcing rings 72 to 74 in the second group. Is configured to be equal to the interval.

The elastomer main body 63 is coupled to the end plate 62, but is attached to the other end plate 61 by utilizing the feature of the shape surface formed on the end plate 61. The end plate 61 and the end plate 62 are regulated by three chain links 79 disposed in a central chamber 76 formed in the elastomer main body 63 so that the interval does not increase beyond a predetermined interval.
JP-A-60-35616 JP-T-2002-527702

  In the force transmission element 50 described in Patent Document 1, a mechanical coupling device including a pair of latches 55 and an annular chain link 56 is disposed in a cylindrical rubber body 53. Therefore, when a compressive load or a tensile load acts on the force transmission element 50, a shear stress is generated between the cylindrical rubber body 53, the pair of latches 55, and the annular chain link 56.

  Due to the generation of the shear stress, the cylindrical rubber body 53 is torn against the pair of latches 55 and the annular chain link 56, and the cylindrical rubber body is brought into contact with the pair of latches 55 and the annular chain link 56. Local microcracks are generated in the body 53. The durability of the force transmission element 50 is reduced by the microcracks generated in the cylindrical rubber body 53, and further, the microcracks grow and develop into large cracks.

  In general, a rubber spring device such as the force transmission element 50 is not always subjected to a compressive force or tensile force in the layer direction. Loads are applied to the rubber spring device from various directions. For example, the force transmission element 50 is deformed in an accordion shape and deformed in a state of multiple degrees of freedom. For this reason, when the metal rings 54 are arranged at equal intervals in the state of being embedded in the cylindrical rubber body 53 like the force transmission element 50, the magnitude of the internal stress in each layer of the cylindrical rubber body 53 is large. Is unevenly distributed, and local cracks are generated starting from the layer on which the internal stress is greatly applied.

  If a crack occurs in the cylindrical rubber body 53, the coupling between the cylindrical rubber body 53 and the metal ring 54 is also released. When such a state occurs, the durability of the force transmission element 50 is significantly reduced, and the force transmission element 50 is damaged.

  Moreover, in the elastomer fixture 60 described in Patent Document 2, the intervals between the metal reinforcement rings 68 to 70 are arranged at the tightest intervals, and the intervals between the metal reinforcement rings 71 and 72 are equal to the metal reinforcement rings 72 to 72. It is configured to be equal to 74 intervals. Further, judging from FIG. 10, the distance between the inner peripheral edge of the metal reinforcing rings 72 and 73 and the central chamber 76 is formed wider than the distance between the metal reinforcing rings 71 and 72.

  Furthermore, the intervals between the metal reinforcing rings 67 and 68 are formed wider than the intervals between the metal reinforcing rings 66 and 67, and the intervals between the metal reinforcing rings 66 to 74 are configured to be unequal. Further, the radial dimension of the elastomer main body 63 between the end plate 61 and the metal reinforcing ring 66 and between the end plate 62 and the metal reinforcing ring 71 is the radial dimension of the elastomer main body 63 between the metal reinforcing rings 67 and 70. It is formed in a smaller constricted shape.

  The elastomer fixture 60 described in Patent Document 2 is configured on the assumption that a compressive force and a tensile force act in the axial direction of the elastomer fixture 60, and thus has the above-described configuration. it is conceivable that. However, when the elastomer fixture 60 is deformed in a multi-degree-of-freedom state like an accordion, the internal stress in each layer of the elastomer main body 63 is unevenly distributed due to the above-described configuration. The maximum internal stress is generated in the thin layer.

  In addition, the internal stress may be abnormally high at the portion of the elastomer body 63 that is constricted and has a small radial dimension. For these reasons, local cracks are generated starting from the place where the internal stress in the elastomer main body 63 becomes large, and the durability of the elastomer fitting 60 is significantly reduced.

  In the present invention, even if the rubber spring device is deformed in a state of multiple degrees of freedom, the internal stress between the layers of the rubber spring is equalized to prevent the occurrence of local cracks and improve durability. It is an object of the present invention to provide a rubber spring device that can be used.

The object of the present invention can be achieved by the inventions described in claims 1 to 2 .
That is, in the first invention of the present application, a laminated structure composed of a plurality of layers in which a rubber layer and a rigid hard plate are alternately bonded, and a pair bonded to the rubber layer disposed on both ends of the stacked structure. A rubber spring device for an articulated dump truck, the rubber spring device being a suspension for an articulated dump truck. , Arranged between the end of the equalizer bar and the axle in the articulated dump truck,
In a stationary state in which no load is applied to the rubber spring device, the hard plates and the pair of rigid end members are arranged in parallel to each other, and the laminated structure has a cavity that penetrates in the lamination direction. The laminated structure is formed in a cylindrical shape having a substantially same cross-sectional shape with respect to the lamination direction, and the thickness of the rubber layer on one end side of the laminated structure is the rubber on the other end side. When the rubber spring device is deformed by applying a load to the rubber spring device, the static force is not applied to the rubber spring device so that the internal stress in each rubber layer of the laminated structure is equalized. the thickness of the in state each rubber layer, wherein the gradually thinned formed to a thickness stepwise in the other end side from the thickness at the one end, the inner peripheral surface of the hollow portion, La It is formed as over surface, the coupling means are no the most important features to become disposed in the cavity.

In the second invention of the present application, the main feature is that the configuration of the laminated structure is specified .

It has been found that when the rubber spring device for an articulated dump truck is deformed into an accordion by the inventor of the present invention, the internal stress increases on one end side of the laminated structure and decreases on the other end side. The present invention is an invention made to suppress this uneven distribution of internal stress. In order to suppress the non-uniform distribution, the rubber layer on one end side of the laminated structure is configured to be thick, and the rubber layer is configured to be thin on the other end of the laminated structure where the internal stress is low. Yes. In addition, the thickness of each rubber layer in the intermediate portion of the laminated structure is formed so as to gradually decrease from the thickness on the one end side to the thickness on the other end side.

  With this configuration, the internal stress in each layer of the rubber spring device can be equalized, and the occurrence of local cracks can be prevented. That is, the thickness of each layer can be changed in accordance with the magnitude of the generated strain. In addition, by forming the inner peripheral surface of the hollow portion of the laminated structure as a rubber surface, when the pair of rigid end members and the laminated structure are manufactured by integral molding, the core forming the hollow portion is taken out. Can be easily.

  Furthermore, by disposing the connecting means in the cavity of the laminated structure, it is possible to prevent the connecting means and the laminated structure from slidingly contacting each other. Thereby, it is possible to prevent the occurrence of local cracks due to the sliding contact between the connecting means and the laminated structure.

  Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. As the configuration of the rubber spring device of the present invention, in addition to the shape and arrangement described below, if the shape and arrangement can solve the problems of the present invention, those shapes and arrangement are adopted. It is something that can be done. For this reason, this invention is not limited to the Example demonstrated below, A various change is possible.

An example in which the rubber spring device is used as a suspension for an articulated dump truck will be described below .

  FIG. 1 shows a side view of an articulated dump truck (hereinafter referred to as a dump truck 1). FIG. 2 is a plan view of the rear frame 22 in a state where the vessel 17 and the like are removed. As shown in FIG. 1, the dump truck 1 includes a front vehicle body 7 located on the front side and a rear vehicle body 8 located on the rear side. The dump truck 1 also includes a front wheel 10, a middle wheel 12, and a rear wheel 14.

  A front vehicle body 7 having front wheels 10 is supported by a front frame 21, and a cab 9 is mounted on the front frame 21. The rear vehicle body 8 including the middle wheel 12 and the rear wheel 14 is supported by a rear frame 22 that is connected to the front frame 21 so as to be refracted and swingable.

  A pair of left and right steering cylinders 26 and 26 are bridged between the front frame 21 and the rear frame 22. The rear frame 22 can be refracted with respect to the front frame 21 by expanding and contracting the steering cylinders 26 and 26, respectively. Thereby, the steering operation of the dump truck 1 can be performed.

  Above the rear frame 22, for example, a vessel 17 for loading a load such as earth and sand is provided. A pair of lift cylinders 20 and 20 are provided between the left and right sides of the front side of the vessel 17 and the rear frame 22. Further, the vessel 17 is rotatably attached to the rear frame 22 via a vessel pin 18 disposed below the rear side of the vessel 17.

  By expanding and contracting the pair of lift cylinders 20, 20, the vessel 17 can be rotated in the vertical direction around the vessel pin 18. When the vessel 17 is raised, an operation called dumping can be performed, and when the vessel 17 is lowered, an operation called dumping can be performed. FIG. 1 shows a state where the vessel 17 is lowered and seated on the rear frame 22.

  A V-shaped front arm 2 is rotatably supported on the front frame 21 in a plan view. In the lower part of the front frame 21, the front end 2A (V-shaped apex side in plan view) of the front arm 2 is supported so as to be freely rotatable in the vertical direction.

  A front axle 11 that supports a pair of left and right front wheels 10, 10 is attached to both end surfaces on the rear end 2B side of the front arm 2. One end of the front suspension cylinder 4 is supported on the front axle 11, and the other end of the front suspension cylinder 4 is supported on the front frame 21.

  As shown in FIGS. 1 and 2, a pair of left and right equalizer bars 23, 23 are rotatably provided on both side surfaces of the rear frame 22. The substantially central portions of the equalizer bars 23 and 23 are rotatably attached to the rear frame 22 via pins 24 and 24. Below the rear frame 22, the center arm 3 and the rear arm 5 are supported so as to be rotatable with respect to the rear frame 22, respectively. As with the front arm 2, the center arm 3 and the rear arm 5 are each formed in a V shape in plan view.

  The front end portion 3A of the center arm 3 is supported at a lower portion on the front side of the rear frame 22 so as to be rotatable in the vertical direction. A center axle 13 that supports a pair of left and right middle wheels 12, 12 is attached to both end surfaces of the rear end portion 3B of the center arm 3. One end of a rubber spring device 30 is supported on the center axle 13, and the other end of the rubber spring devices 30, 30 is supported on the front end side of the equalizer bars 23, 23.

  The front end portion 5A of the rear arm 5 is supported at a lower portion on the rear side of the rear frame 22 so as to be rotatable in the vertical direction. A rear axle 15 that supports a pair of left and right rear wheels 14, 14 is attached to both end surfaces of the rear end portion 5B of the rear arm 5. One end of the rear suspension cylinder 6 is supported on the rear end 5B or the rear axle 15, and the other end of the rear suspension cylinder 6 is supported on the rear end of the equalizer bar 23.

  FIG. 3 shows an external view of the rubber spring device 30 in an unloaded state, and FIG. 4 shows a longitudinal sectional view of the rubber spring device 30 in an unloaded state. A plurality of rigid plates 32 and rubber layers 33 (33a to 33m) made of rubber are alternately bonded to form a cylindrical laminated structure 31, and in the center of the laminated structure 31 A cylindrical cavity 34 penetrating in the stacking direction is formed.

  The hard plate 32 is formed in a disk shape having a hole having a slightly larger dimension than the cavity 34 at the center. Moreover, although the material and the shape are respectively equal, the material and thickness can be determined in consideration of the maximum stress of the rubber spring device 30 and the like.

  In addition, although the cross-sectional shape of the rubber spring device 30 will be described below in a circular shape, the cross-sectional shape of the rubber spring device 30 is not limited to a circular shape, the cross-sectional shape is an elliptical shape, etc. It can also be set as the shape.

  Rigid end members 35 and 36 are bonded to the rubber layers 33a and 33m at both ends of the laminated structure 31, respectively. In the no-load state, the hard plate 32 and the rigid end members 35 and 36 are arranged in parallel to each other. Further, a connecting means composed of U-shaped latches 38 and 39 connected by a chain link 40 is disposed in the cavity 34 between the pair of rigid end members 35 and 36. A rubber spring device 30 is constituted by a pair of rigid end members 35 and 36 bonded to both ends of the laminated structure 31 and a connecting means.

  The rigid end member 36 has a stepped hole penetrating with an inner diameter substantially corresponding to the cavity 34 of the laminated structure 31. The flange portion 39a of the U-shaped latch 39 can be brought into contact with a stepped hole formed in the rigid end member 36. Further, the bolt 38 a of the latch 38 is passed through the hole formed in the rigid end member 35, and the nut 41 is screwed on the outer surface side of the rigid end member 35. Thus, the flange portion 38b of the U-shaped latch 38 can be brought into contact with the inner surface side of the hole formed in the rigid end member 35, and the interval between the pair of rigid end members 35 and 36 is equal to or greater than a predetermined interval. It can be regulated by connecting means so as not to become.

3 and 4, the rubber layer 33m on the rigid end member 36 side is configured to be thicker, and the rubber layer 33a on the rigid end member 35 side is configured to be thinner than the rubber layer 33m.
The thickness of the rubber layer on the rigid end member 36 side is not limited to the configuration in which only the rubber layer 33m is thickened, but the rubber layers 33l, 33k and the like laminated on the rubber layer 33m are disposed on the rubber layer 33m. It can also be configured thickly. Similarly, the thickness of the rubber layer on the rigid end member 35 side is not limited to the configuration in which only the rubber layer 33a is thinned, but the rubber layers 33b, 33c, etc., which are laminated below the rubber layer 33a, etc. The rubber layer 33a can also be made thin. Furthermore, the number of rubber layers is an example, and the present invention is not limited to the total number of rubber layers shown.

  The rubber layer in the intermediate portion of the laminated structure 31 is changed from the thickness on the rigid end member 36 side to the thickness on the rigid end member 35 side as being laminated from the rigid end member 36 side to the rigid end member 35 side. In addition, the thickness is gradually reduced step by step.

  Further, the inner peripheral surface of the laminated structure 31 facing the cavity portion 34 is covered with rubber so that the embedded hard plate 32 is not exposed to the cavity portion 34 side. The structure covered with the rubber can be formed as follows. First, the pair of rigid end members 35 and 36 and the plurality of hard plates 32 are fixed to a plate fixing mold. Then, in order to form the hollow portion 34, a core having a diameter smaller than that of the hole portion of the hard plate 32 is inserted from the stepped hole of the rigid end member 36 until the other rigid end member 35 is reached.

  At this time, if the core is disposed away from the hard plate 32, when the rubber agent is filled and molded, as described above, the inner peripheral surface of the laminated structure 31 facing the cavity 34 is the rubber. It can be set as the shape coat | covered by. Further, with such a configuration, the core forming the cavity 34 can be easily extracted after the structure is molded.

  In consideration of the insertion / extraction operation of the core as described above, it is desirable that the size of the stepped hole of the rigid end member 36 is substantially equal to the size of the hole of the hard plate 32.

  Accordingly, the structure can be easily molded. On the other hand, in the elastomer fixture described in Patent Document 2 described above, the metal reinforcing ring of the first group is exposed to the central chamber. The inner peripheral edge meshes, making it difficult to remove the core after molding.

  In addition, since the outer peripheral edge of each rubber layer 33a to 33m is disposed inside the outer peripheral edge of the hard plate 32, the rubber spring device 30 is compressed, and each rubber layer 33a to 33m swells to the outer peripheral side. Even in the case where the rubber plate protrudes, the swelled rubber layer can be prevented from jumping to the outer peripheral side larger than the outer peripheral edge of the hard plate 32.

  Thereby, the bonding state between the rubber layers 33a to 33m and the pair of rigid end members 35 and 36 and the hard plate 32 is maintained, and the rubber layers 33a to 33m and the pair of rigid end members 35 and 36 and the hard plate 32 are disposed. The generation of cracks in can be prevented. On the other hand, in the elastomer mounting tool described in Patent Document 2 described above, the elastomer main body in the first group portion is arranged in a form covering the outer peripheral edge of the metal reinforcing ring.

  For this reason, when a compressive load is applied to the elastomer fixture, the amount of movement of the metal reinforcing ring in the stacking direction differs from the amount of movement of the elastomer body protruding from the outer peripheral edge of the metal reinforcing ring in the stacking direction. A situation occurs in which the elastomer main body protruding from the outer peripheral edge is sheared by the outer peripheral edge of the ring. As described above, the elastomer fixture described in Patent Document 2 has a configuration in which cracks easily occur in the elastomer body.

  5 and 6 are side views in which the center arm 3 and the equalizer bar 23 are partially enlarged with the rubber spring device 30 as the center. FIG. 5 shows a state in which both middle wheels 12 of the center axle 13 are dropped and a tensile load is applied to the rubber spring device 30. FIG. 6 shows a state in which both middle wheels 12 (see FIG. 1) of the center axle 13 ride on a mound and the like and a compression load is applied to the rubber spring device 30.

  As shown in FIGS. 5 and 6, stoppers 27 are provided on both side surfaces of the rear frame 22 so as to correspond to the front end portion and the rear end portion of each equalizer bar 23, respectively. The amount of rotation of the equalizer bar 23 is regulated by the stopper 27. In addition, illustration of the stopper in a rear-end part is abbreviate | omitted. Each stopper at the front end portion and the rear end portion is configured to protrude slightly from the side surface of the rear frame 22 toward the equalizer bar 23.

  FIG. 5 shows, for example, a state in which the dump truck 1 shown in FIG. 1 is supported by the front wheels 10 and the rear wheels 14 and the middle wheel 12 is floating above the hollow. In this state, the center arm 3 rotates in the clockwise direction shown in the figure, the rear end portion of the equalizer bar 23 comes into contact with a stopper (not shown), and the equalizer bar 23 is fixed in the counterclockwise direction shown in the figure. It will be restricted that it rotates above. At this time, since the distance between the pair of rigid end members 35 and 36 is regulated by the connecting means, a tensile load acts on the rubber spring device 30 in the direction indicated by the arrow.

  The rubber springs are different because the rotation center of the members (equalizer bar 23 and center axle 13) to which the rigid end members 35 and 36 are attached (the pin 24 is the equalizer bar 23 and the front end 3A is the center axle 13). The device 30 is transformed into the accordion shape shown in FIG. Further, since the distance between the rigid end members 35 and 36 by the connecting means is restricted to a predetermined distance or less, the front portion of the dump truck 1 in the rubber spring device 30 is compressed and deformed, and the dump of the rubber spring device 30 is compressed. The rear part of the truck 1 is pulled and deformed. Accordingly, the rubber spring device 30 is deformed into an accordion shape with the line 30a drawn in the lateral direction on the lower end side of the rubber spring device 30 as a bent portion.

  Further, as shown in FIG. 6, when the middle wheel 12 rides on a small mountain or the like, the center arm 3 rotates in the counterclockwise direction shown in the figure, and the front end portion of the equalizer bar 23 comes into contact with the stopper 27. Thus, the equalizer bar 23 is restricted from rotating more than a certain amount in the clockwise direction shown in the figure. Accordingly, a compressive load indicated by an arrow acts on the rubber spring device 30.

  Since the rotation center of the member (equalizer bar 23 and center axle 13) to which the rigid end members 35 and 36 are attached (the pin 24 in the equalizer bar 23 and the front end portion 3A in the center axle 13) is different, FIG. It is deformed into an accordion shape opposite to the case shown by. For this reason, each layer of the rubber spring device 30 is not uniformly compressed, and the rear side portion is more compressively deformed than the front side.

  Thus, as the deformation of the rubber spring device 30 during traveling of the dump truck 1, many accordion-shaped deformations occur. Next, the magnitude of the internal stress generated in each rubber layer when the rubber spring device is deformed in an accordion shape will be described.

  The stress distribution in the rubber spring device 45 in which the hard plates 32 are arranged at equal intervals, and the thickness of the rubber layer on one end side of the laminated structure 31 is increased as in the present invention, and stepwise as it goes to the other end side. FIG. 7 and FIG. 8 show the analysis results of the stress distribution in the rubber spring device 30 configured to be thin.

  FIG. 7 relates to a rubber spring device 45 in which hard plates 32 are arranged at equal intervals, and FIG. 8 relates to a rubber spring device 30 of the present invention. FIGS. 7 and 8 show the stress distribution on the side where the tensile force is deformed when the rubber spring devices 45 and 30 are deformed into an accordion shape. The black part indicates the part where the highest stress is generated. Further, the stress at that time is shown by gradually increasing the density of dots as the stress decreases from the highest state.

  As shown in FIG. 7, in the rubber spring device 45 in which the hard plates 32 are arranged at equal intervals, the highest stress expressed in black is generated across each layer. In particular, the area of the portion where the highest stress is generated on the bottom surface side of the rubber spring device 45 is wide, and the area of the portion where the highest stress is generated decreases from the bottom surface side to the upper end side. Moreover, when the stress distribution state in the layer on the upper end side is seen, the area of the portion where the next highest stress shown in black is generated is substantially the same over each layer.

  On the other hand, in the rubber spring device 30 of the present invention, the highest stress state expressed in black as shown in FIG. 8 does not occur in any layer. In addition, the area of the portion where the next highest stress is generated, which is the highest stress shown in black, gradually decreases from the bottom side layer to the upper end side layer, but with the bottom side layer There is no significant change between the upper end side layers. For this reason, the stress distribution generated in each layer is a substantially uniform pressure distribution.

  As described above, in the rubber spring device 30 of the present invention, even when the rubber spring device 30 is deformed into an accordion shape, the highest stress state represented by black does not occur in any layer. In addition, as the stress distribution state in each layer, since low stress is distributed in a substantially equal state, the occurrence of cracks in each layer can be reliably prevented.

  As the thickness of the rubber layer of the rubber spring device 30 of the present invention, the rubber layer should be formed to a thickness that can withstand the compressive load and not to generate a high stress state such that the tensile stress is shown in black by the tensile load. is required.

  The technical idea of the present invention can be applied to a device or the like to which the technical idea of the present invention can be applied.

It is a side view of a dump truck. (Example) It is the top view which expanded the rear frame. (Example) It is a front view of a rubber spring device. (Example) It is a longitudinal cross-sectional view of a rubber spring device. (Example) It is the side view to which the rubber spring apparatus vicinity was expanded when the rubber spring apparatus was deform | transformed. (Example) FIG. 5 is an enlarged side view of the vicinity of the rubber spring device when the rubber spring device is separately deformed. (Example) It is a stress distribution map of a rubber spring device. (Comparative example) It is a stress distribution map of a rubber spring device. (Example) It is a longitudinal cross-sectional view of a rubber spring device. (Conventional example 1) It is a longitudinal cross-sectional view of a rubber spring device. (Conventional example 2)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Dump truck, 2 ... Front arm, 3 ... Center arm, 5 ... Rear arm, 10 ... Front wheel, 11 ... Front axle, 12 ... Middle wheel, 13 ... Center axle, 14 ... rear wheel, 15 ... rear axle, 21 ... front frame, 22 ... rear frame, 23 ... equalizer bar, 26 ... steering cylinder, 30 ... Rubber spring device, 31 ... laminated structure, 32 ... hard plate, 33 ... rubber layer, 34 ... cavity, 35 ... rigid end member, 36 ... rigid end member, 38 ... U-shaped latch, 39 ... U-shaped latch, 40 ... Chain link, 45 ... Rubber spring device, 50 ... Force transmitting element, 51, 52 ... End plate, 53 ... Cylindrical rubber body, 54 ... Metal ring 55 ... Hasp, 56 ... Chain link, 60 ... Elastomer fitting, 61, 62 ... Metal end plate, 63 ... Elastomer body, 66-74 ... Metal reinforcement ring, 76・ ・ Central room.

Claims (2)

A laminated structure composed of a plurality of layers in which a rubber layer and a rigid hard plate are alternately bonded, a pair of rigid end members bonded to the rubber layers disposed at both ends of the laminated structure, and the rigidity In a rubber spring device for an articulated dump truck , comprising a connecting means for restricting the spread of the gap between the end members,
The rubber spring device is disposed as a suspension for the articulated dump truck between the end of the equalizer bar in the articulated dump truck and the axle.
In a stationary state where no load is applied to the rubber spring device, the hard plates and the pair of rigid end members are arranged in parallel with each other,
The stacked structure has a hollow portion penetrating in the stacking direction in a central portion of the stacked structure, and is configured in a cylindrical shape having substantially the same cross-sectional shape with respect to the stacking direction,
The thickness of the rubber layer on one end side of the laminated structure is formed thicker than the thickness of the rubber layer on the other end side,
The thickness of each rubber layer in a stationary state in which no load is applied to the rubber spring device so that the internal stress in each rubber layer of the laminated structure is equalized when the rubber spring device is deformed by applying a load. Is formed gradually and gradually from the thickness at the one end side to the thickness at the other end side,
The inner peripheral surface of the hollow portion is formed as a rubber surface,
A rubber spring device for an articulated dump truck , wherein the connecting means is arranged in the cavity. The rubber spring device for an articulated dump truck according to claim 1, wherein the laminated structure is formed in a substantially cylindrical shape.

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