JP3759521B2 - Axle chassis connection structure of work vehicle - Google Patents

Description

  The present invention relates to an axle chassis connection structure for connecting an axle of a work vehicle such as a wheeled hydraulic excavator and a chassis frame.

  7 to 10 show an example of a conventional suspension system for a wheeled hydraulic excavator. FIG. 7 is a side view of a lower traveling body of a wheeled hydraulic excavator. Reference numeral 1 denotes an axle on the front wheel side, reference numeral 2 denotes an axle on the rear wheel side. The drive shaft 2a is inserted. Traveling driving force is transmitted from the transmission 3 through the shafts 4 and 5 to the front driving shaft 1a and the rear driving shaft 2a. As shown in FIG. 8, a chassis frame 7 is coupled to a front upper axle 1 by a pin 6 so as to be swingable in the lateral direction of the vehicle. The revolving frame provided on the chassis frame 7 so as to be able to revolve is provided with a work seat (not shown) including a driver's seat, a boom, an arm, a bucket, and the like, as shown in FIG. Are each equipped with a single acting cylinder 8. In FIG. 8, the code | symbol 11 shows a tire.

As shown in FIGS. 9 and 10, the single-acting cylinder 8 has a tube 8 a attached to the chassis frame 7 with a bolt 9 via a flange portion 8 d, and a tip end of the piston rod 8 b protruding from the axle 1. It is in contact with the bracket 10. When traveling, the cylinder chamber 8c of the cylinder 8 is connected to the tank, and the piston rod 8b freely expands and contracts to improve the ground contact between the left and right tires. During the excavation work, the cylinder chamber 8c is hydraulically locked, and the chassis frame 7 is fixed to the axle 1 so as to stabilize the vehicle body during the excavation work. The structure described above is also described in Patent Document 1.
Japanese Utility Model Publication No.59-89162

However, in such a conventional suspension system for work vehicles, the axle 1 and the chassis frame 7 are directly connected by the pin 6 and no shock absorber is provided between them. Directly input to the chassis frame, there was a problem in ride performance .

Therefore, when a shock absorber is interposed to improve the riding comfort performance, the suspension device used in a dump truck or the like can hold a heavy body frame itself, A working vehicle such as a wheeled hydraulic excavator needs to perform excavation work in addition to normal traveling, and a large excavation reaction force is applied in the vehicle front-rear, vehicle left-right, and up-down directions. Suspension devices cannot be used. An object of the present invention is to provide an axle chassis connection structure capable of ensuring the stability of a vehicle body during work and during travel in a work vehicle that performs work such as excavation in addition to travel.

The present invention is applied to an axle chassis connection structure of a work vehicle having an axle provided on at least one of the front wheel side and the rear wheel side so as to be movable at least in the vertical direction with respect to the chassis frame. A link is disposed between the chassis frame and the axle, and one end of the link is attached to the chassis frame so as to restrict the displacement in the front-rear and left-right directions between the chassis frame and the axle and to allow the displacement in the up-down direction. pair to link restriction surface provided with is formed in contact with the vehicle longitudinal direction is connected to the chassis frame by a pin that extends in the longitudinal direction of the vehicle, the other end is provided in the vehicle longitudinal direction end portions of the axle It is characterized in that it is connected to the axle by a pin extending in the vehicle front-rear direction while being formed so as to be in contact with the link restricting surface from outside.
A pair of link restriction surfaces of the chassis frame may be provided facing the vehicle longitudinal direction, and one end of the link may be formed so as to be sandwiched between the pair of link restriction surfaces.
It is also possible to pin-connect the link-side connection point of the link to the vehicle center portion of the axle and pin-link the chassis frame-side connection point of the link to the side of the chassis frame.
A pair of links, each of which has a width substantially equal to or greater than the width in the front-rear direction of the axle and extends from the front connection point and the rear connection point to the chassis frame to the front connection point and the rear connection point to the axle. You may make it have a member and the reinforcement member provided so that a pair of connecting member may be connected to a vehicle front-back direction.

According to the present invention, a link is disposed between the chassis frame and the axle, and one end of the link is formed so as to contact the link regulating surface provided on the chassis frame in the vehicle longitudinal direction and extends in the vehicle longitudinal direction. The pin is connected to the chassis frame, and the other end is formed so as to be in contact with the pair of link restricting surfaces provided on the axle from the outside, and is connected to the axle by a pin extending in the vehicle front-rear direction. As a result, the front / rear / left / right displacement between the chassis frame and the axle can be restricted to allow the displacement in the up / down direction, ensuring the stability of the vehicle during travel and work even when a shock absorber is interposed. can do.

  An embodiment when the present invention is applied to a suspension device of a wheel type hydraulic excavator will be described with reference to FIGS. The same parts as those in FIGS. 7 to 10 are denoted by the same reference numerals, and different points will be mainly described.

  FIG. 1A illustrates a schematic configuration of a suspension device according to the present invention. Buffer springs 21L and 21R are interposed between the axle 1 and the chassis frame 7, and a tube side 22a and a rod side 22b of a pair of return cylinders 22L and R provided at a predetermined distance in the vehicle left-right direction are respectively connected to the chassis. The frame 7 and the axle 1 are connected by pins 23a and 23b. Also, the horizontal displacement in the front / rear / left / right direction between the chassis frame 7 and the axle 1 is restricted, and the vertical displacement is allowed. Is connected to the center of the vehicle.

  As shown in FIG. 1B, the rod chamber 22c and the bottom chamber 22d of the return cylinders 22L and 22R are connected to the tank 42 via pilot operated check valves 41L and R, respectively. The pilot ports of the pilot operated check valves 41L and 41R are connected to a hydraulic pressure source 44 via an electromagnetic switching valve 43, and a solenoid portion 43S of the electromagnetic switching valve 43 is connected to a battery 46 via a switch 45.

  The switch 45 is opened during excavation work, and the switch 45 is closed during traveling. When the switch 45 is closed, the switching valve 43 is switched to the position “a”, pressure oil acts on the pilot ports of the pilot operated check valves 41L and 41R from the hydraulic pressure source 44, and the pilot operated check valves 41L and 41R are opened. The moving cylinders 22L, R are free. When the switch 45 is opened, the switching valve 43 is switched to the b position, and the pilot ports of the pilot operated check valves 41L and 41R communicate with the tank 42 so that the bottom chamber 22d and the rod chamber 22c are connected by the pilot operated check valves 41L and R. Each is shut off and the return cylinders 22L and 22R are locked.

  It should be noted that throttles may be provided in the pipe lines 47L, R during traveling so that the return cylinders 22L, R function as hydraulic dampers.

  2 is a side view of a wheel-type hydraulic excavator in which the suspension device according to this embodiment is installed on the front wheel side, FIG. 3 is an enlarged view of a main part of FIG. 2 showing details of a buffer spring mounting part, and FIG. FIG. 2 is a plan view showing the details, and the left side of FIGS. 2 and 3 is the rear side of the vehicle, and the lower side of FIG. 4 is the rear side of the vehicle. In the following description, L and R are omitted for the left and right members.

  As well shown in FIG. 3, the buffer spring 21 is a leaf spring attached to the bottom surface of the axle 1 with an attachment member 31, and the chassis frame 7 is formed on the upper surface of both ends of the leaf spring 21 in the vehicle front-rear direction. Spring receiving portions 7 a and 7 b projecting downward from the tire are brought into contact with each other, and the impact from the tire 11 is absorbed by the leaf spring 21.

  3 and 4, the link 24 includes a cylindrical pin connecting portion 24a connected to the chassis frame 7 with a pin 25a, a flange-like pin connecting portion 24b connected to the axle 1 with a pin 25b, and both pin connecting portions 24a. , 24b and a pair of upper and lower lid plates 24d. By such connection of the chassis frame 7 and the axle 1 by the link 24, horizontal displacement in the front-rear and left-right directions between the chassis frame 7 and the axle 1 is restricted, and displacement in the up-down direction is allowed.

  Among the members constituting the link 24, the strength in the left-right direction of the vehicle is secured particularly by the side plate 24c. The side plate 24c is greatly reinforced particularly in the vehicle front-rear direction by joining the cover plate 24d, and the single link 24 is given high strength in both the vehicle front-rear direction and the left-right direction. In this example, the side plate 24c is a connecting member, and the lid plate 24d is a reinforcing member.

  5 and 6 show details of the attachment portion of the return cylinder 22, FIG. 5 is a view of the right end of the vehicle as seen from the rear side of the vehicle, and FIG. 6 is a front view thereof. A block 7c having a load receiving portion 7d projecting is welded to the right side surface of the chassis frame 7, and a pair of brackets 32 provided with a load receiving portion 32a that engages with the load receiving portion 7d is attached to the block 7c. Screwed with bolts 33. Pins 23 a project from the opposite side surfaces of the tube 22 a of the return cylinder 22 in the vehicle front-rear direction, the pin 23 a is inserted into the bracket 32, and the return cylinder 22 is connected to the chassis frame 7. On the other hand, a pair of brackets 1b are provided on the upper surface of the axle 1, and the piston rod 22b of the return cylinder 22 is connected to the axle 1 by a pin 23b.

The operation of the suspension device configured as described above will be described.
During traveling, the switch 45 is closed, and the rod chamber 22c and the bottom chamber 22d of the return cylinders 22L and 22R are both in communication with the tank so as to be free. When the right tire rides on a certain step, the leaf spring 21R bends, and the axle 1 swings clockwise in FIG. 1 about the pin 25b. At this time, the piston rod 22b of the pair of left and right return cylinders 22L and 22R expands and contracts according to the swing of the axle 1. Here, although the hydraulic resistance force is generated to some extent by the expansion and contraction of each of the return cylinders 22L and 22R, the impact from the road surface is absorbed mainly by the bending of the leaf spring 21.

  When receiving an impact from the left tire, the impact force buffering action by the leaf spring 21 is the same as the swing direction of the axle 1 is reversed. Further, when the left and right tires run on the steps at the same time, the left and right leaf springs 21R and 21L are bent at the same time to absorb the impact. At this time, the leaf spring 21 bends until the return cylinder 22 contracts to the contracted end. When both tires fall from the step, they are restored until the return cylinder 22 advances to the extended end.

  Thus, since the impact from the road surface is mainly absorbed by the leaf springs 21R and 21L, the impact from the road surface does not directly act on the chassis frame 7 as in the prior art. Further, when the tire that has climbed the step falls, the axle 1 has conventionally fallen following the tire. According to this example, the axle 1 is connected to the chassis frame 7 by the return cylinder 22. Therefore, the return cylinder 22 drops more slowly than before due to the resistance force when the return cylinder 22 extends. As described above, riding comfort is improved by the suspension device of this example.

  Furthermore, conventionally, the chassis frame 7 is tilted due to the rolling load that acts during high-speed turning, but according to the suspension shown in the figure, the moment load that acts on the chassis frame 7 around the pin 25b due to the rolling load is the leaf spring 21R. , L is absorbed by the spring force of L, the inclination of the chassis frame 7 during high-speed turning travel is suppressed, and rolling resistance is improved as compared with the conventional case.

  The reason why the both ends of the leaf springs 21R and 21L are not fastened to the chassis frame 7 is as follows. Since the chassis frame 7 is connected to the axle 1 by the link 24, the chassis frame 7 is displaced left and right. Therefore, the leaf springs 21R and 21L are not fastened to the chassis frame 7, and the left and right movement of the chassis frame 7 is allowed.

  When the function of the hydraulic damper is given to the return cylinder 22, the moment load acting on the chassis frame 7 around the pin 25b due to the rolling load is the spring force of the leaf springs 21R and L and the oil of the return cylinders 22L and R. Absorbed by pressure

  On the other hand, at the time of excavation, the switch 45 is opened, the rod chamber 22c and the bottom chamber 22d of the return cylinder 22 are shut off by the pilot operated check valves 41L, R, and the return cylinders 22L, R are locked to lock the leaf springs 21L, R. Block operation. As a result, the swing of the chassis frame 7 around the pin 25 b is restricted by the return cylinder 22, and the movement in the vehicle front-rear and left-right direction is restricted by the link 24. Therefore, even if the ride comfort performance is improved by using the leaf springs 21L and 21R than before, the vehicle stability during excavation is not impaired.

  Further, a pin 23 a is projected from an intermediate portion of the tube 22 a of the return cylinder 22, and the return cylinder 22 is connected to the chassis frame 7 by this pin 23 a, so that the tube base end portion is connected to the chassis frame 7. Compared to the case, the overall length of the suspension device in the height direction can be shortened.

  Furthermore, since the load receiving portion 32a of the bracket 32 to which the return cylinder 22 is attached is engaged with the load receiving portion 7d of the chassis frame 7, the load is applied to the mounting bolt 33 for the bracket 32 by a load during excavation or a road surface input load. No shearing force is applied and there is no problem in strength.

Incidentally, since the chassis frame in the link you above mentioned pivots relative to the axle, is not restricted strictly displacement of the vehicle transverse direction of the chassis frame, it may be linked such as to restrict any displacement in the horizontal direction, Various types of links can be used . The suspension rack apparatus has been described for the case where the front wheel side, may be provided on both or only the front and rear wheel rear wheel side.

  Although the wheeled hydraulic excavator has been described, the present invention can also be applied to various work vehicles that travel and work.

FIG. 1A is a diagram showing a schematic configuration of a suspension device for a work vehicle according to an embodiment of the present invention. FIG.1 (b) is a figure which shows the hydraulic circuit which switches locking / unlocking of the return cylinder shown to Fig.1 (a). The side view of the wheel-type hydraulic excavator which installed the suspension apparatus by a present Example in the front-wheel side. The principal part enlarged view of FIG. 2 which shows the detail of a buffer spring attaching part. The principal part enlarged plan view of FIG. 2 which shows the detail of the attachment part of a link. The figure which showed the detail of the attachment part of a return cylinder, and looked at the vehicle right end part from the vehicle rear side. The right view of FIG. The side view of the wheel-type hydraulic shovel which shows schematic structure of the conventional suspension apparatus. The figure which looked at the suspension apparatus of FIG. 7 from the vehicle front. FIG. 8 is a detailed view of a mounting portion of the single acting cylinder of FIG. The top view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Axle 7 Chassis frame 24 Link 24a, 24b Pin connection part 24c Side plate 24d Cover plate 25a, 25b Pin

Claims (4)

In an axle chassis connection structure for a work vehicle having an axle provided on at least one of the front wheel side and the rear wheel side so as to be movable at least in the vertical direction with respect to the chassis frame,
A link is disposed between the chassis frame and the axle;
The link has one end in the vehicle front-rear direction on a link restriction surface provided on the chassis frame so as to restrict displacement in the front-rear and left-right directions between the chassis frame and the axle and to allow displacement in the up-down direction. A pair of pins that are formed in contact with each other and are connected to the chassis frame by pins extending in the vehicle front-rear direction, with the other end in contact with a pair of link restriction surfaces provided in the vehicle front-rear direction from the outside. An axle chassis connecting structure for a work vehicle, wherein the axle chassis connecting structure is connected to the axle by a pin formed in the longitudinal direction and extending in the vehicle longitudinal direction.
  2. The chassis frame according to claim 1, wherein a pair of link restriction surfaces of the chassis frame are provided opposite to each other in the vehicle longitudinal direction, and one end of the link is formed so as to be sandwiched between the pair of link restriction surfaces. A structure for connecting an axle chassis of a work vehicle as described in 1.   3. The link-side connecting point of the link is pin-coupled to a vehicle central portion of the axle, and the chassis-frame-side connecting point of the link is pin-connected to the side of the chassis frame. The axle chassis connection structure of the working vehicle as described in 2. The link has a width substantially equal to or greater than the width in the front-rear direction of the axle, from a front connection point and a rear connection point with the chassis frame to a front connection point and a rear connection point with the axle. The axle chassis connection structure for a work vehicle according to claim 2 or 3, further comprising a pair of connecting members extending respectively and a reinforcing member provided so as to connect the pair of connecting members in the vehicle front-rear direction.

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