JP2004026155A - Cylinder mounting structure of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the total length in the height direction of a suspension device used for a wheel type hydraulic shovel. <P>SOLUTION: A pair of left and right reciprocating cylinders 22L and 22R are provided between a chassis frame 7 and an axle 1. Pins 23a are protrudingly provided on two opposing side faces of tubes 22a of each of the reciprocating cylinders 22, and the pins 23a are fitted to a pair of brackets 32 which sandwich the cylinders 22. The brackets 32 are fastened to the chassis frame 7 with a bolt 33, and tips of rods 22b of the cylinders 22 are connected to the axle 1. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a mounting structure for a cylinder mounted on a work vehicle such as a wheel-type hydraulic excavator.

FIGS. 7 to 10 show an example of a conventional suspension system for a wheel-type hydraulic excavator. FIG. 7 is a side view of the lower traveling body of the wheel type hydraulic excavator, 1 is an axle on the front wheel side, 2 is an axle on the rear wheel side, and a front drive shaft 1a and The drive shaft 2a is inserted. A traveling driving force is transmitted from the transmission 3 to the front drive shaft 1a and the rear drive shaft 2a via shafts 4 and 5. As shown in FIG. 8, a chassis frame 7 is connected to a center upper portion of the front wheel axle 1 by a pin 6 so as to be swingable in the left-right direction of the vehicle. A work attachment including a driver's seat, a boom, an arm, a bucket, and the like (not shown) is provided on a turning frame rotatably provided on the chassis frame 7, and as shown in FIG. Are mounted with single-acting cylinders 8, respectively. In FIG. 8, reference numeral 11 denotes a tire.

As shown in FIGS. 9 and 10, the single-acting cylinder 8 has a tube 8a attached to a chassis frame 7 by bolts 9 via a flange 8d, and a tip of a piston rod 8b protruding above the axle 1. It is in contact with the bracket 10. During traveling, the cylinder chamber 8c of the cylinder 8 is connected to the tank so that the piston rod 8b freely expands and contracts, so that the right and left tires have good contact with the ground. During excavation work, the cylinder chamber 8c is hydraulically locked, and the chassis frame 7 is fixed to the axle 1 to stabilize the vehicle body during excavation work.

However, in such a conventional suspension device for a work vehicle, the axle 1 and the chassis frame 7 are directly connected by the pins 6 and no shock absorber is provided between them, so that the impact from the road surface during traveling can be reduced. It was directly input to the chassis frame, and there was a problem with ride comfort. Further, the moment load around the pin 6 acts on the chassis frame 7 due to the rolling load during high-speed turning, but the single-acting cylinder 8 is free and cannot support the moment load, and the chassis frame 7 is undesired. I will tilt.

A suspension device used for a dump truck or the like can itself hold a body frame that is quite heavy, but a work vehicle such as a wheel-type hydraulic excavator to which the present invention is applied is not limited to ordinary traveling, such as excavation work. And a large excavation reaction force is applied in each of the front and rear directions, the left and right directions of the vehicle, and the up and down directions, so that a suspension device such as a truck cannot be adopted.

The present invention relates to a mounting structure of a cylinder mounted on a work vehicle, wherein a pair of pins project from a tube of the cylinder symmetrically with respect to the cylinder tube, and the pins are respectively fitted to a pair of brackets sandwiching the cylinder. In this case, the bracket is fastened to the cylinder mounting member of the work vehicle with a bolt.
A bracket may be attached to the cylinder-attached member so that a shear force does not act on the bolt due to the load input via the cylinder.
The pin is preferably provided at a longitudinally intermediate portion of the tube.
It is also possible to have a pair of front and rear axles provided to be at least vertically movable with respect to the chassis frame, fasten the bracket to the chassis frame, and connect the cylinder rod to the axle.

According to the present invention, a pair of pins are symmetrically protruded from the cylinder tube with respect to the cylinder tube, each pin is fitted to a pair of brackets sandwiching the cylinder, and the bracket is fastened to the cylinder member by bolts. I did it. Thereby, the overall length of the suspension device in the height direction can be reduced.

An embodiment in which the present invention is applied to a suspension system 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 differences will be mainly described.

FIG. 1 (a) 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 the tube side 22a and the rod side 22b of the pair of reciprocating cylinders 22L and R provided at a predetermined distance in the vehicle left-right direction are respectively chassis. It is connected to the frame 7 and the axle 1 by pins 23a and 23b. In addition, the horizontal displacement between the chassis frame 7 and the axle 1 in the front-rear and left-right directions is restricted, and the vertical displacement is permitted. One end of the link 24 is connected to the chassis frame 7 by a pin 25a, and the other end is connected to the axle 1 by a pin 25b. Of the vehicle.

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

ス イ ッ チ Open the switch 45 during excavation work and close the switch 45 during traveling. When the switch 45 is closed, the switching valve 43 is switched to the position a, and hydraulic oil acts on the respective pilot ports of the pilot operation check valves 41L and 41R from the hydraulic pressure source 44 to open the pilot operation check valves 41L and 41R. The dynamic cylinders 22L, R are free. When the switch 45 is opened, the switching valve 43 is switched to the position "b", and the pilot ports of the pilot operation check valves 41L, R communicate with the tank 42, and the bottom chamber 22d and the rod chamber 22c are opened by the pilot operation check valves 41L, R. Each of them is shut off, and the return cylinders 22L, R are locked.

It is to be noted that the throttles 22L, R may function as hydraulic dampers by providing throttles in the pipelines 47L, R during traveling.

FIG. 2 is a side view of a wheel-type hydraulic excavator in which the suspension device according to the present 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 portion, and FIG. 2 and FIG. 3 is a vehicle rear side, and the lower part of FIG. 4 is a vehicle rear side. In the following description, L and R are omitted for the same members on the left and right sides.

As shown in FIG. 3, the buffer spring 21 is a leaf spring attached to the bottom surface of the axle 1 by an attachment member 31. The spring receiving portions 7a and 7b projecting downward from the abutment are in 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 by a pin 25a, a flange-shaped pin connecting portion 24b connected to the axle 1 by a pin 25b, and both pin connecting portions 24a. , 24b, and a pair of upper and lower lid plates 24d. By the connection between the chassis frame 7 and the axle 1 by such a link 24, the horizontal displacement between the chassis frame 7 and the axle 1 in the front-rear and left-right directions is restricted, and the vertical displacement is allowed.

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

FIGS. 5 and 6 show details of the mounting portion of the return cylinder 22. FIG. 5 is a view of the right end of the vehicle as viewed from the rear of the vehicle, and FIG. 6 is a front view thereof. A block 7c provided with a load receiving portion 7d 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 engaged with the load receiving portion 7d are provided on the block 7c. It is screwed with a bolt 33. Pins 23a project from the two opposite sides of the tube 22a of the return cylinder 22 in the vehicle front-rear direction. The pins 23a are inserted into the brackets 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 reciprocating cylinder 22 is connected to the axle 1 by pins 23b.

The operation of the suspension device configured as described above will be described.
During traveling, the switch 45 is closed, and both the rod chambers 22c and the bottom chambers 22d of the return cylinders 22L and 22R are communicated with the tank to be in a free state. When the right tire rides on a step, the leaf spring 21R bends, and the axle 1 swings clockwise in FIG. 1 around the pin 25b. At this time, the piston rods 22b of the pair of left and right return cylinders 22L, R expand and contract in accordance with the swing of the axle 1. Here, a certain degree of hydraulic resistance is also generated by the expansion and contraction of each of the return cylinders 22L and R, but the impact from the road surface is mainly absorbed by the bending of the leaf spring 21.

を 受 け る When receiving a shock from the left tire, the shock absorbing effect of the leaf spring 21 is the same, except that the swing direction of the axle 1 is reversed. When the left and right tires ride on the step at the same time, the left and right leaf springs 21R and 21L simultaneously bend and absorb the impact. At this time, the leaf spring 21 bends until the return cylinder 22 contracts to the contraction end. When both tires fall from the step, the tire is restored until the backward moving cylinder 22 advances to the extension end.

衝 撃 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 related art. In addition, when the tire riding on the step falls, the axle 1 conventionally falls following the tire, but according to this example, the axle 1 is connected to the chassis frame 7 by the return cylinder 22. Therefore, the return cylinder 22 falls more slowly than before due to the resistance force when the backward movement cylinder 22 extends. As described above, the riding comfort is improved by the suspension device of this example.

Further, conventionally, the chassis frame 7 was tilted by the rolling load applied during high-speed turning, but according to the suspension shown in the figure, the moment load applied to the chassis frame 7 around the pin 25b by the rolling load is a leaf spring 21R. , L, the inclination of the chassis frame 7 during high-speed turning is suppressed, and the rolling resistance is improved as compared with the conventional case.

両 端 The reason why both ends of the leaf springs 21R, L 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 21R are not fastened to the chassis frame 7 to allow the chassis frame 7 to move in the left-right direction.

When the return cylinder 22 is provided with a function of a hydraulic damper, the moment load acting on the chassis frame 7 around the pin 25b due to the rolling load depends on the spring force of the leaf springs 21R and L and the oil of the return cylinder 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 and 41R, and the return cylinders 22L and R are locked to lock the leaf springs 21L and R. Block operation. As a result, the swing of the chassis frame 7 around the pin 25b is restricted by the backward movement cylinder 22, and the movement in the vehicle front-rear and left-right directions is restricted by the link 24. Therefore, even if the ride comfort performance is improved more than before using the leaf springs 21L and 21R, the stability of the vehicle body during excavation is not impaired.

Further, a pin 23a is protruded from an intermediate portion of the tube 22a of the return cylinder 22, and the return cylinder 22 is connected to the chassis frame 7 by the pin 23a. In this case, the total length of the suspension device in the height direction can be reduced.

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 receiving portion 32a of the bracket 32 is attached to the mounting bolt 33 of the bracket 32 by a load during excavation or a road surface input load. There is no shear force and there is no problem in strength.

It should be noted that the present invention is not limited to the above embodiments, and the following modifications are possible.
(1) A coil spring can be used as a buffer spring. In this case, it is preferable to provide a function of a hydraulic damper to the return cylinder.
(2) The structure of the return cylinder may be any structure as long as it is locked during excavation and becomes free during traveling.
(3) Since the chassis frame swings with respect to the axle in the link described above, the displacement of the chassis frame in the lateral direction of the vehicle is not strictly restricted. However, a link that regulates any displacement in the horizontal direction may be used. Various types of links can be used.
(4) Although the case where the suspension device is provided on the front wheel side has been described, it may be provided only on the rear wheel side or on both the front and rear wheels.

Although the description has been given of the wheel type hydraulic excavator, the present invention can be applied to various work vehicles that perform traveling and work.

FIG. 1A is a diagram illustrating a schematic configuration of a suspension device for a work vehicle according to an embodiment of the present invention. FIG. 1B is a diagram showing a hydraulic circuit for switching between locking and unlocking of the return cylinder shown in FIG. 1A. The side view of the wheel type hydraulic shovel in which the suspension device by this example was installed in the front wheel side. FIG. 3 is an enlarged view of a main part of FIG. 2 showing details of a buffer spring mounting portion. 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 from the vehicle rear side. The right view of FIG. The side view of the wheel type hydraulic shovel which shows the schematic structure of the conventional suspension device. The figure which looked at the suspension system of FIG. 7 from the vehicle front. FIG. 8 is a detailed view of a mounting portion of the single-acting cylinder in FIG. 7. The top view of FIG.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Axle 7 Chassis frame 7c Block 7d Load receiving part 22L, 22R Reversing cylinder 22a Tube 22b Rod 23a, 23b Pin 32 Bracket 32a Load receiving part 33 Bolt

Claims (4)

A mounting structure for a cylinder mounted on a work vehicle,
A pair of pins are symmetrically protruded from the cylinder tube with respect to the cylinder tube,
The pins are respectively fitted to a pair of brackets sandwiching the cylinder,
The cylinder mounting structure for a work vehicle, wherein the bracket is fastened to a cylinder mounting member of the work vehicle with a bolt. The cylinder mounting structure for a working vehicle according to claim 1, wherein the bracket is mounted to the cylinder mounting member so that a shear force does not act on the bolt due to a load input through the cylinder. The cylinder mounting structure for a working vehicle according to claim 1 or 2, wherein the pin is provided at an intermediate portion in a longitudinal direction of the tube. The work vehicle has a pair of front and rear axles provided movably at least vertically with respect to a chassis frame, the bracket is fastened to the chassis frame, and a rod of the cylinder is connected to the axle. The cylinder mounting structure for a working vehicle according to any one of claims 1 to 3, wherein:

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