JP6016458B2 - Suspension device for work vehicle - Google Patents

Description

  The present invention relates to a suspension device for a work vehicle that suspends left and right axles, and more particularly, to a suspension device for a work vehicle having a fixed axle.

  2. Description of the Related Art Conventionally, a technique in which a suspension device is disposed between an axle (axle case) and an airframe frame in order to improve the riding comfort of a work vehicle and improve traveling performance is known. For example, it is a technique shown in Patent Document 1. A conventional suspension device is provided with a center pin having an axial center in the front-rear direction at the center of the left and right sides of the front axle case, and a support member is swingably supported with respect to the body frame via the center pin. A pair of left and right leaf springs are interposed between the member and the body frame. A pair of left and right vertical hydraulic cylinders that can selectively restrict or release the vertical position of the support member with respect to the body frame are interposed between the support member and the body frame, and further, the support A pair of left and right lateral hydraulic cylinders that can selectively restrict or release the rotation angle of the front axle case with respect to the member are interposed between the support member and the front axle case.

  With this configuration, when traveling on rough terrain at low speed, the vertical hydraulic cylinder is fixed, the horizontal hydraulic cylinder functions as a damper, and the front axle case can swing around the center pin to improve traveling performance. I was letting. Further, when traveling on the leveling surface at high speed, the horizontal hydraulic cylinder is fixed, the vertical hydraulic cylinder functions as a damper, and the front axle case can be displaced up and down to improve riding comfort.

Japanese Patent No. 4054725

  However, in the case of the technique in Patent Document 1, two pairs of left and right hydraulic cylinders are required, and switching control means for the hydraulic cylinders are also required. Therefore, the number of parts is complicated and expensive. . In addition, since leaf springs were used, the leaf springs had to be placed below the front axle case, resulting in a lower minimum ground clearance, which was disadvantageous for speed sprayers that run under orchard shelves. . Further, since the leaf spring is long in the front-rear direction, the turning angle must be reduced to avoid interference when the steering wheel is turned left and right during turning.

  The present invention has been made in view of the above circumstances, and provides a suspension device for a work vehicle that has a simple structure, does not require a control device, and is inexpensive.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

According to a first aspect of the present invention, the rear end of the swing arm is rotatably supported by the body frame provided in the front-rear direction of the work vehicle, and a front axle case is disposed in the front-rear direction of the swing arm in the front-rear direction. It is rotatably supported by a center pin having an axis, and an elastic member is interposed between the swing arm and the fuselage frame, and the elastic member is disposed inside and outside on the same axis. A shock absorber and a coil spring, and an elastic member receiving portion is formed in the front and rear middle portion of the swing arm. The elastic member receiving portion is a through hole into which a lower portion of the shock absorber can be inserted. And a spring receiving surface for receiving the coil spring .

  As an effect of the present invention, riding comfort performance can be improved by a suspension device having a simpler structure than conventional ones.

The whole side view of a speed sprayer provided with the suspension apparatus concerning embodiment of this invention. The perspective view of the suspension apparatus which concerns on embodiment of this invention. FIG. Similarly front view. Similarly side view. The perspective view of a swing arm.

  A speed sprayer as an embodiment of a work vehicle will be described from the overall configuration with reference to FIG. The speed sprayer 1 has a driving operation unit 3 disposed on the front portion of the machine body frame 2 and a steering handle, a shift lever, a work lever, and the like. A chemical liquid tank 4 is disposed on the front and rear center of the machine body frame 2, and an engine room 5 is disposed at the rear of the chemical liquid tank 4, and the engine and the power sprayer are accommodated in the engine room 5. A spray unit 6 is disposed at the rear of the engine room 5, and a fan 7 and a nozzle are disposed in the spray unit 6.

  Thus, the power sprayer and the fan 7 are driven by the power from the engine, the chemical liquid is sucked from the chemical liquid tank 4 by the driving of the power sprayer and discharged from the nozzle, and the discharged chemical liquid is diffused by the air blown by the fan 7. Sprayed on fruit trees.

  A front axle case 11 is supported on the front portion of the body frame 2 via the suspension device 10 of the present invention, and front wheels 8 and 8 serving as steering wheels are supported on the left and right sides of the front axle case 11. A rear axle case is fixed to the rear part of the body frame 2, and rear wheels 9, 9 are supported on the left and right sides of the rear axle case. Note that the speed sprayer 1 of the present embodiment is a four-wheel drive, and the power from the engine is transmitted to the front wheels 8 and 8 and the rear wheels 9 and 9 via a transmission case.

  As shown in FIGS. 1, 2, and 5, the airframe frame 2 includes a connecting frame 12 in which a pair of right and left prismatic pipes extend in the front-rear direction, and the left and right prismatic pipes are appropriately spaced apart from each other. It is connected and reinforced by the framework structure. Further, a front axle case placement portion 2a is formed at the front portion of the body frame 2 where the front axle case 11 is placed, and is curved so as to bypass the front axle case 11 upward and is formed in a substantially inverted U shape in side view. 2a is formed, and a swinging space is formed between the left and right sides of the front axle case 11, and the airframe is low and the front axle case 11 is mounted as high as possible so that the ground height of the traveling airframe is lowered. This makes it easy to run under the shelf.

  Next, an embodiment of the suspension device 10 of the present invention will be described with reference to FIGS. The suspension device 10 is arranged between the airframe frame 2 and the front axle case 11, and when traveling on an uneven ground surface, the suspension device 10 reduces impact and improves not only the riding comfort but also the traveling performance. is there. The suspension device 10 includes a swing arm 13, an elastic member 14, and stoppers 15 and 16. Further, the elastic member 14 includes a coil spring 141 and a shock absorber 142.

  The swing arm 13 connects the front axle case 11 to the body frame 2 so as to be able to move up and down and tilt and swing left and right. As shown in FIGS. 2, 3, 5, and 6, the swing arm 13 is formed in a substantially V shape in a plan view and a substantially inverted U shape in a side view, and is disposed at the left and right center of the front axle case 11. It is arranged above the vicinity of the differential case 11a.

  The rear part of the swing arm 13 is bent downward in a “h” shape and divided into left and right forks, and rear support parts 13a and 13a are formed at the rear end. The rear support portions 13a and 13a have bearing holes penetrating in the left-right direction. The support shafts 20 and 20 project from the body frame 2 and are inserted into the bearing holes, so that the swing arm 13 pivots on the body frame 2. The front portion of the swing arm 13 is supported so as to be swingable up and down with the support shaft 20 as a rotation fulcrum.

  A front portion of the swing arm 13 extends downward, and a front support portion 13b is formed at the front end. A bearing hole penetrating in the front-rear direction is opened in the left and right center of the front support portion 13b, and a center pin 21 protruding forward from the front surface of the left and right center of the front axle case 11 is inserted into the bearing hole. The center pin 21 is supported so as to be able to tilt and swing left and right. The center pin 21 also protrudes rearward from the left and right center rear surfaces of the front axle case 11, and is rotatable by a support 22 projecting downward from the lower surface of the front and rear middle part of the swing arm 13, as shown in FIG. It is supported and the support rigidity is increased.

  Elastic member receiving portions 13c and 13c are formed on both the left and right sides of the swing arm 13 in the middle of the front and rear. The elastic member receiving portion 13c includes a spring receiving surface 131, a through hole 132, and a shaft hole 133 on the upper surface. The spring receiving surface 131 is a portion that receives a lower portion of a coil spring 141, which will be described later, and the through hole 132 is opened through in the vertical direction so that the lower portion of the shock absorber 142 (piston rod 142b) can be inserted. Yes. The shaft hole 133 is opened through in the left-right direction, supports the support shaft 23 in the shaft hole 133 to support the lower end of the shock absorber 142 (piston rod 142b), and the lower end of the shock absorber 142 with respect to the swing arm 13 It is pivotably supported.

  Stopper mounting portions 13d and 13d are formed on the swing arm 13 near the elastic member receiving portions 13c and 13c. In this embodiment, the stopper mounting portion 13d is configured between the front support portion 13b and the elastic member receiving portion 13c. However, the stopper mounting portion 13d may be located behind or on the side of the elastic member receiving portion 13c and is not limited. . The stopper attaching portion 13d has a through hole opened in the vertical direction so that the stopper 15 can be attached to the lower surface of the swing arm 13 with a bolt or the like.

  The elastic member 14 is interposed between the body frame 2 and the swing arm 13 and absorbs an impact. Specifically, the lower portion of the elastic member 14 is supported by the elastic member receiving portions 13c and 13c of the swing arm 13, and the upper portion of the elastic member 14 is between the upper portions of the left and right front axle case arrangement portions 2a and 2a of the body frame 2. It is supported by the elastic member receiving portions 24a and 24a of the receiving plate 24 provided horizontally. Thus, since the elastic member 14 is arranged at the center of the left and right sides of the machine body and above the swing arm 13, the elastic member 14 is arranged compactly without interfering with the front wheels 8 arranged on both sides of the front axle case 11 during turning. The configuration is as follows.

  The left and right sides of the receiving plate 24 are fixed to the upper portions of the front axle case arrangement portions 2a, 2a of the body frame 2 by bolts 26, 26,. Elastic member receiving portions 24 a and 24 a are formed on the left and right sides of the receiving plate 24. The elastic member receiving portion 24 a includes a spring receiver 24 b formed on the lower surface of the receiving plate 24 and a rod support portion 24 c formed on the upper surface of the receiving plate 24. The spring receiver 24b is configured in a dish shape, and the upper part of the coil spring 141 is fitted therein. A shim is interposed between the spring receiver 24b and the coil spring 141, and the load of the coil spring 141 can be finely adjusted by increasing or decreasing the shim. This adjustment can change the ride comfort. The rod support portion 24c is provided with a plate body that is bent in a U-shape in plan view from the upper surface around the through hole opened in the elastic member receiving portion 24a, and the upper portion of the cylinder 142a of the shock absorber 142 passes through the through hole. The upper part of the shock absorber 142 is supported by the elastic member receiving portion 24a so as to be swingable.

  The coil spring 141 is a compression spring, and a coil spring 141 that bends a predetermined length when the chemical tank 4 is full is used. The coil spring 141 is configured to be detachable. That is, when it is desired to change the bending length of the coil spring 141, the coil spring 141 can be replaced with a coil spring 141 having a different spring constant. In this replacement, the receiving plate 24 can be easily removed by removing the bolts 26, 26... Fixing the receiving plate 24 to the front axle case arrangement portion 2a of the body frame 2 and removing the support shaft 25. The coil spring 141 can be pulled upward and exchanged.

  The shock absorber 142 includes a cylinder 142a, a piston rod 142b, and a piston, and is housed so as to penetrate through the inside of the coil spring 141 on the axial center side. The shock absorber 142 houses a piston fixed to one end of the piston rod 142b in the cylinder 142a, and the cylinder 142a is partitioned into two chambers by the piston. The piston or cylinder 142a is provided with a known valve (not shown) so that the two chambers can flow through the valve. The cylinder 142a is filled with oil (or gas), and the oil in the cylinder moves from one chamber to the other chamber via a valve when the airframe vibrates or swings. The shock is attenuated by the resistance when passing. The valve is constituted by a variable valve, and the attenuation value can be changed by changing the passage amount of the valve.

  The stopper 15 is attached to the left and right of the swing arm 13 and swings by abutting against the contact bodies 27 and 27 provided on the front axle case 11 when the swing arm 13 swings up and down around the support shaft 20. It is something to regulate. The stoppers 15 and 15 are made of an elastic member such as rubber, absorb the shock at the time of contact, and are attached to the lower surfaces of the stopper mounting portions 13d and 13d of the swing arm 13. Abutting bodies 27 are fixed to the left and right sides of the central differential case 11 a of the front axle case 11 below the stopper 15, and the stopper 15 is disposed so as to be able to abut on the abutting body 27. The stopper 15 is arranged at the front portion of the swing arm 13, that is, at a position away from the support shaft 20 serving as a rotation fulcrum, so that the maximum swing width is made as large as possible.

  The stoppers 16 are attached to the left and right front axle case placement portions 2a of the body frame 2, and contact bodies 28 and 28 provided on the front axle case 11 when the front axle case 11 is tilted to the left and right about the center pin 21. It abuts and restricts left-right tilt. The stoppers 16 and 16 are made of an elastic member such as rubber, absorbs a shock at the time of contact, and are attached to the front left and right outer lower portions of the front axle case arrangement portion 2a. The stopper 16 is disposed so as to be able to come into contact with a contact body 28 fixed to the left and right sides of the lower front axle case 11. The stopper 16 is arranged at a position away from the center pin 21 on both left and right outer sides of the swing arm 13 so as not to interfere with the swing arm 13 and the elastic member 14 when swinging.

  As described above, the rear end of the swing arm 13 is supported at the center of the front and rear of the body frame 2 provided in the front-rear direction so that the rear end of the swing arm 13 can be pivoted up and down, and the front axle that supports the front wheel 8 is supported on the front side of the swing arm 13. The front side of the swing arm 13 is rotatably supported by a center pin 21 that extends around the upper side of the case 11 and has a longitudinal axial center provided at the center of the front axle case 11. Since the elastic member 14 is interposed between the front side of the front frame case 2 and the front axle case disposing portion 2a formed to be curved so as to bypass the front axle case 11 upward at the front portion of the body frame 2, it is easier than before. Riding comfort performance can be improved by the suspension device 10 having a simple structure. Since the elastic member 14 is arranged in the vertical direction, the elastic member 14 is not elongated in the front-rear direction like a leaf spring, but is compact, and the swing arm 13 and the elastic member 14 are arranged on the left and right center side of the body. Therefore, there is no possibility of interference when the front wheel 8 is turned to the left or right.

  Further, since the elastic member 14 is constituted by the coil spring 141 and the shock absorber 142, not only can the vertical spring shock be reduced by the coil spring 141, but also the vibration can be attenuated by the shock absorber 142. The comfort can be further improved. Further, since the shock absorber 142 can be arranged inside the coil spring 141, it can be configured more compactly. Further, since the shock absorber is configured so that the damping force can be adjusted, the damping force can be adjusted in accordance with the operator's preference, driving technique and traveling road surface, and traveling stability can be further improved. The suspension device 10 of the present embodiment can also be applied to a rear axle case that supports the rear wheel 9.

2 Airframe Frame 13 Swing Arm 11 Front Axle Case 21 Center Pin 14 Elastic Member 10 Suspension Device 141 Coil Spring 142 Shock Absorber

Claims (1)

The body frame provided in the longitudinal direction of the work vehicle has a rear end of the swing arm supported rotatably.
A front axle case is rotatably supported by a center pin having an axial center in the front-rear direction below the front side of the swing arm.
Between the swing arm and the body frame, an elastic member is interposed,
The elastic member includes a shock absorber and a coil spring arranged inside and outside on the same axis,
An elastic member receiving part is formed in the front and rear halfway part of the swing arm ,
The suspension device for a work vehicle, wherein the elastic member receiving portion includes a through hole into which a lower portion of the shock absorber can be inserted and a spring receiving surface for receiving the coil spring .

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