JP2002266367A - Structure of connecting pin for working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of problems such as the seizure and galling of a pin, caused by low viscosity of an working fluid, in a structure of the connecting pin, which makes one member connected in a freely disengaged manner by the pin disposed in the other member so as to be freely slidable between 'a protrusive position' and 'a retractive position' by a fluid of a fluid pressure source of a working machine. SOLUTION: A fluid transducer is interposed between the pin and the fluid pressure source so as to enable a fluid, which has good lubricity and is different from the fluid of the fluid pressure source, to be used as a fluid for making the pin operate while sliding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting pin structure for a working machine, and more particularly, to a working machine suitable for use in a quick coupler device for detachably and quickly connecting a working device to a working arm. It relates to a connecting pin structure.

[0002]

2. Description of the Related Art For example, a hydraulic shovel, which is a typical example of a working machine, can perform various works by replacing a working device mounted on a tip of a working arm via a pin with a different working device. Work such as excavation and loading of earth and sand by installing a bucket, work such as quarrying and road crushing by installing a hydraulic breaker, and work such as demolition of a structure by installing a crusher. Is done. Therefore, if various working devices such as buckets, breakers, and crushers are appropriately attached and detached and replaced, one hydraulic excavator can be used for multiple purposes and multiple functions.

[0003] Therefore, in this type of working machine, a quick coupler device (hereinafter, may be simply referred to as a quick coupler) in which a working device can be detachably and quickly connected to a working arm by operation from a driver's seat. Is prepared. A typical example of this quick coupler will be described with reference to FIGS. The quick coupler, generally designated by reference numeral 40, includes a pair of pins 44, 44 slidably disposed on the same axis on a boss 42a at the distal end of a working arm 42. The pin 44 has a piston portion 44a for sliding the pin 44 using hydraulic oil of a hydraulic source of a work machine. The bearing hole 42b in which the pin 44 slides is provided with an oil seal 43a for stopping leakage of hydraulic oil to the outside and a dust seal 43b for stopping entry of foreign matters such as earth and sand from the outside. The pair of pins 44,
It is urged by a compression spring 46 interposed therebetween in a direction to protrude outward from the working arm 42, and by applying hydraulic pressure to the piston portion 44 a with hydraulic oil, the pin 4
4, 44 are retracted inwardly of the working arm 42 against the urging force of the spring 46 (the state shown in FIG. 4).

A bucket 48 as a working device connected to the pins 44, 44 swings about the pins 44, 44, and the tip of a swinging movement member 50 provided on the working arm 42 is provided with a pin 44. , 44 are provided substantially in parallel with each other, and pins 52 are provided at both ends thereof. Pins 44, 4
A frame 5 for defining an axial distance between the pin 4 and the pin 52
4 are provided. The bucket 48 is provided with a pair of brackets 56 having a pair of cutout grooves 56a and 56b opened in opposite directions to the outside of the frame body 54.

In order to connect the bucket 48 to the working arm 42 and the swinging movement member 50, first, the protruding pin 52 of the swinging movement member 50 is engaged with one of the notches 56a, 56a. Thereafter, each of the pins 44, 44 of the working arm 42 is released from the hydraulic oil from the hydraulic pressure source 58 so as to protrude from the frame 54 by the force of the spring 46, and the other cutout grooves 56b, 5b
6b. Thus, the bucket 48 is connected. In order to remove the bucket 48 from the working arm 42 and the swinging motion member 50, the hydraulic oil is supplied to the pins 44, 44 and retracted into the frame 54, and the notch grooves 56 b , 56b, and then the pin 52 and the notches 56a, 56a. Thus,
The bucket 48 is detachably connected to the working arm 42 and the swinging movement member 50.

[0006]

However, the slidable connecting pin structure such as the pins 44 provided in the conventional quick coupler 40 of the above-described type has the following problems to be solved. is there.

That is, the sliding portion of the pin 44 is lubricated by the working oil having a low viscosity of the working machine, and the area of the bearing portion is limited in order to install the oil seal 43a and the dust seal 43b. When a large load acts on the bearing portion and a large force is applied to the bearing portion, the pin 44 and the bearing hole 42b are seized due to lack of oil or the like, and damage such as galling easily occurs. When such damage occurs, the dust seal 43a, the oil seal 43b, and the like are also damaged, so that the hydraulic oil easily leaks to the outside, and foreign matter such as earth and sand easily enters the inside.

In order to solve the above-mentioned problems, the viscosity of the hydraulic oil is increased, a dedicated hydraulic system is provided to operate the pins using gear oil or grease, or lubricating grease is injected into the bearing portion. , And so on. However, if the viscosity of hydraulic oil is increased, the pressure loss of the hydraulic device of the work machine increases, deteriorating the performance of the work machine, the cost of the dedicated hydraulic system increases, and the injection of grease into the bearings requires the use of hydraulic oil. Therefore, means for preventing the mixing of the components is required, and the bearing area is reduced.

The present invention has been made in view of the above-mentioned circumstances, and a technical problem of the present invention is to provide a hydraulic device for a working machine without causing a problem of pressure loss and providing a hydraulic system exclusively for pin operation. It is an object of the present invention to provide a connecting pin structure of a working machine, which can appropriately operate and lubricate a connecting pin slidably provided without modifying a bearing portion.

[0010]

According to the first aspect of the present invention, there is provided a fluid conversion device interposed between a pin slidably disposed on one member and a fluid pressure source of a working machine. The pin moves between a `` protruding position '' in which the tip end protrudes from the one member and passes through the other member and a `` pull-in position '' which retracts into the one member. The other member is detachably connected to one member, and the fluid converter is
A fluid chamber to which the fluid of the fluid pressure source is connected, a fluid chamber to which the fluid for moving the pin is connected, and the two fluid chambers are movably isolated to enable transmission of fluid pressure between the two fluids. A connecting pin structure for a working machine, comprising a separating member.

Then, by using the fluid converter,
In the part that moves the pin, any fluid with good lubricity different from the fluid pressure source fluid of the work machine is used without impairing the performance of the fluid pressure device of the work machine, and a dedicated hydraulic system It can be used without providing a bearing and without modifying the bearing part.

According to a second aspect of the present invention, in the connecting pin structure for a working machine according to the first aspect, the fluid for moving the pin has a higher viscosity than the fluid of the fluid pressure source.

As the fluid for moving the pin, a well-lubricated fluid having a high viscosity such as well-known gear oil or grease used in a working machine is used.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The pin connection structure of a working machine constructed in accordance with the present invention will be described below in more detail with reference to the accompanying drawings, which show a preferred embodiment of a hydraulic shovel as a typical working machine. Will be described.

Referring to FIG.
The hydraulic excavator indicated by a symbol has a body body 4 and a working device 6 connected to the body body 4 so as to be vertically swingable. The working device 6 includes a boom 6a supported by the body body 4 so as to be swingable in the vertical direction, a boom operating cylinder 6b interposed between the body body 4 and the boom 6a, and swinging in the vertical direction by the tip of the boom 6a. An arm 6c that is freely supported, an arm operating cylinder 6d that is interposed between the boom 6a and the arm 6c, a bucket 6e that is a working device that is vertically swingably supported at the tip of the arm 6c, and an arm 6
bucket link 6 interposed between c and bucket 6e
f and a bucket working cylinder 6g.

Connection pin structure 8 constructed according to the present invention
However, it is used as a quick coupler for detachably and quickly connecting a bucket 6e as an other member to an arm 6c as one member.

The connection pin structure 8 will be described with reference to FIG. The connecting pin structure 8 includes a pair of pins 12, 12 slidably disposed on the same axis 10 on the arm 6 c, and a pin 1.
It has a pair of fluid converters 16, 16 interposed between the fluid pressure sources 2, 12, and the fluid pressure source 14 of the work machine. Between the fluid pressure source 14 and the fluid converters 16, 16, a hydraulic fluid of a working machine as a working fluid is interposed.
Gear oil having a higher viscosity than hydraulic oil as a working fluid is interposed between the pins 6 and 16 and the pins 12 and 12.

A cylindrical boss 7 is provided at the tip of the arm 6c.
Are provided integrally with each other in the direction of the axis 10. The boss 7 is formed with a pair of piston sliding holes 7a, 7a extending in the direction of the axis 10. Piston sliding holes 7a, 7
a is communicated by a communication hole 7b having a smaller diameter than the piston sliding hole 7a. A screw hole 7c is formed at the outer open end of each of the piston sliding holes 7a. A bearing cylinder 18 is attached to each of the open ends of the piston sliding holes 7a. The bearing cylinder 18 has a male screw portion 18a attached to the screw hole 7c, a cylindrical portion 7b inserted into the piston sliding hole 7a, and a bearing hole 18c penetrating in the direction of the axis 10.
An annular seal groove is formed in the bearing hole 18c on the male screw portion 18a side. A head-side flow path 7d penetrates through the communication hole 7b from outside the boss 7, and a piston slide hole 7a,
A rod-side flow path 7e penetrates from the outside of the boss 7 to the bearing cylinder 18 side of each 7a.

An oil seal 20 for preventing gear oil from leaking to the outside and a dust seal 22 for preventing foreign matter such as earth and sand from entering from outside are mounted in the annular seal groove of the bearing hole 18c. An oil seal 24 for preventing gear oil from leaking outside is attached to an annular groove formed in the boss 7 on the outer peripheral portion of the bearing cylinder 18. The oil seal 20 is a well-known rod seal made of a sliding ring and an O-ring, the dust seal 22 is a well-known lip seal, and the oil seal 24 is a well-known seal made of an O-ring.

The pin 12 has a large-diameter piston portion 12a and a small-diameter pin portion 12b. The outer diameter of the pin portion 12b is finished so as to be slidably inserted into the bearing hole 18c of the bearing cylinder 18, and the outer diameter of the piston portion 12a is provided with a predetermined gap in the piston sliding hole 7a. It is finished to the dimensions to be inserted. An annular seal groove is formed in the outer peripheral portion of the piston portion 12a, and the piston seal 12c
Is installed. The piston seal 12c is formed of a known seal including a sliding ring and an O-ring.

On the boss 26 of the bucket 6e of the working device,
A bearing hole 26a is formed at both ends of the boss 7 of the arm 6c in the direction of the axis 10 and through which the tip of the pin portion 12b of the pin 12 is inserted so as to be able to enter and exit.

The pin 12 has a "protruding position (indicated by a solid line)" in which the tip of the pin 12b protrudes from the bearing tube 18 of the arm 6c and is inserted into the bearing hole 26a of the bucket 6e. Withdrawal position (indicated by a two-dot chain line) ".

Continuing the description with reference to FIG.
The head-side flow path 7d formed in the boss 7 of FIG.
a through one fluid converter 16 to the fluid pressure source 14
In addition, the rod-side flow paths 7e, 7e are connected to the fluid pressure source 14 via the other fluid converter 16 by a pipe 28b. The fluid pressure source 14 is
It is a well-known hydraulic source for operating the boom operating cylinder 6b, the arm operating cylinder 6d, the bucket operating cylinder 6g, and the like described above (FIG. 1). The fluid pressure source 14 includes a well-known directional control valve 15 for supplying and discharging hydraulic oil, and includes a pipe 28a,
28b is connected to the direction switching control valve 15. The fluid pressure source 14 is disposed on the body of the working machine. The pair of fluid converters 16 and 16 may be, depending on the form, size, etc. of the working machine, the body body, the boom 6a, or the arm 6c.
And so on. Fluid converter 16, 1
It is desirable that the arrangement position of 6 is as close to the pin 12 as possible.

The fluid converter 16 includes a cylindrical main body 16a having both ends closed, and a pair of pistons 16 provided slidably in the axial direction in the main body 16a and connected to each other.
b and 16b, and a port for connecting a pipe is formed at each of both ends. The pistons 16b, 16
The main body 16a is divided into a fluid chamber 30 on one side and a fluid chamber 32 on the other side with b as an isolation member. Piston 16
An annular seal groove is provided on the outer peripheral portion of each of the b and 16b, and a piston seal 34 for sealing the inner peripheral surface of the main body 16a is attached.

Therefore, the fluid chamber 3 of the fluid converter 16
When a fluid flows into either one of the fluids 0 and 32, the fluid slides the pistons 16b and 16b, and the fluid in the other fluid chamber is pushed out from the fluid chamber, and the pressure between the two fluids is transmitted. Note that the pistons 16b, 16b may be formed as one piece. The fluid converter 16 can be basically constituted by a well-known hydraulic cylinder.

The operation of the connecting pin structure 8 of the working machine as described above will be described with reference to FIG.

(1) Operation to the pin "projecting position": When the operator of the work machine operates the direction switching control valve 15 of the fluid pressure source 14 to supply the hydraulic oil to the pipe 28a in the direction shown by the arrow X, The hydraulic oil flows into the fluid chamber 30 of one of the fluid converters 16, and the gear oil, which is the fluid in the fluid chamber 32, is pushed out through the pistons 16 b, 16 b to be pushed out of the head-side flow path 7 of the boss 7.
d, and moves the pair of pins 12, 12 to a “projected position (shown by a solid line)”. The gear oil pushed out from the rod side flow path 7e of the boss 7 by the movement of the pins 12, 12 is:
The fluid flows into the fluid chamber 32 of the other fluid converter 16 and pushes out the hydraulic oil in the fluid chamber 30 through the pistons 16b, 16b. Flows to When the operation of the direction switching control valve 15 is stopped, the flow of the hydraulic oil and the gear oil is stopped, and the pair of pins 12, 12 are held at the "projected position".

(2) Operation to Pin “Retracted Position”: Pin 1
The operation to the "retracted position" of steps 2 and 12 is opposite to the operation to the "projected position" described above, and the direction switching control valve 15 is operated to supply the hydraulic oil of the fluid pressure source 14 to the pipe line 28b by the arrow Y Supply in the direction indicated by. Hydraulic oil is supplied to the fluid chamber 3 of one fluid converter 16.
0, and flows into the fluid chamber 3 through the pistons 16b, 16b.
The second gear oil flows into the rod-side flow path 7e of the boss 7 to move the pair of pins 12, 12 to the "pull-in position (indicated by a two-dot chain line)". The gear oil pushed out from the head side flow path 7d of the boss 7 by the movement of the pins 12, 12 flows into the fluid chamber 32 of the other fluid converter 16, and the piston 1
The hydraulic oil in the fluid chamber 30 is pushed out through 6b and 16b,
The extruded hydraulic oil flows to the fluid pressure source 14 through the pipe 28a in the direction indicated by the arrow Y. When the operation of the direction switching control valve 15 is stopped, the flow of hydraulic oil and gear oil stops, and the pair of pins 1
2 and 12 are held at the "retracted position".

(3) As described above, the pair of pins 12, 1
2 is positioned at the "projecting position" from the arm 6c as one member, so that the tip of each pin 12 has a pair of bearing holes 26a, 26 of the bucket 6e as the other member.
a, and one member 6c is connected to the other member 6e. Then, the pair of pins 12, 12 are moved to the "retracted position".
, The connection between one member 6c and the other member 6e is released.

(4) Pin lubrication: Since the pin 12 is operated and lubricated by a high-viscosity gear oil having better lubricity than the hydraulic oil, lubrication of the sliding portion of the pin 12 can be improved. In addition, seizure and galling of the sliding portion can be prevented.

As described above, the present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above-described embodiments. It can be changed or modified.

(1) Fluid converter: In the embodiment of the present invention, a cylindrical main body 16a as a fluid converter, and a piston 16b slidably provided in the main body 16a,
Although a fluid pressure cylinder type having a hydraulic cylinder 16b is shown, one fluid chamber and the other fluid chamber are of a oscillating fluid motor type in which vanes are provided so as to be able to oscillate about an axis. You may.

(2) Fluid Converter: In the embodiment of the present invention, the fluid converter 16 is formed with the same inner diameter of a pair of fluid chambers 30, 32 in the form of a hydraulic cylinder. The size of each fluid may be changed to increase or decrease the pressure of the fluid between the pair of fluid chambers 30 and 32, and increase or decrease the flow velocity.

(3) Pins: In the embodiment of the present invention, the pair of pins 12, 12 are configured to move between the "projected position" and the "retracted position" by the fluid. As shown in FIG. 4, a biasing spring is provided between the pair of pins, and only the operation in the direction opposite to the spring force is operated by the fluid converted from the fluid of the fluid pressure source via the fluid transducer. You may.

(4) Fluid: In the embodiment of the present invention, gear oil is used as the fluid for moving the pin, but a fluid having better lubricity, for example, high-viscosity grease may be used.

(5) Quick coupler: In the embodiment of the present invention, the connecting pin structure 8 is used in a portion of the quick coupler that connects the arm 6c as one member and the bucket 6e as the other member. However, the use of the connecting pin structure of the present invention is not limited only to quick couplers.

(6) Quick coupler: In addition to the portion connecting the arm 6c and the bucket 6e in the embodiment of the present invention, the connecting pin structure of the present invention is used to connect the bucket link 6f and the bucket 6e (FIG. You may use it also for 1). In that case, the connecting portion of the arm 6c and the connecting portion of the bucket link 6f may be simultaneously operated,
It may be operated separately.

(7) Accumulator: head side flow path 7 of fluid converter 16 and pin 12 in the embodiment of the present invention
An accumulator, which is a pressure accumulator, may be provided in the conduit 28a connecting to the line d, and a pressure maintaining mechanism for maintaining a holding force for holding the pin 12 at the “projecting position” may be added.

(8) Pipes: In the embodiment of the present invention, pipes 28a and 28 connecting the fluid pressure source 14 and the pin 12
8b, the fluid pressure source 14 and the fluid converter 1
6. There is no difference between the fluid converter 16 and the pin 12, but since a high-viscosity fluid is used between the fluid converter 16 and the pin 12, if pressure loss is a problem, The inner diameter between them may be increased.

[0040]

According to the connecting pin structure of the working machine constructed in accordance with the present invention, the fluid pressure device of the working machine does not cause a pressure loss problem, and a hydraulic system dedicated to pin operation can be provided. The present invention provides a connecting pin structure for a working machine, in which a slidably provided connecting pin can be appropriately operated and lubricated without modifying a bearing portion.

[Brief description of the drawings]

FIG. 1 is a side view of a hydraulic excavator which is a typical work machine having a connecting pin structure configured according to the present invention.

FIG. 2 is an enlarged sectional view of a portion of a pin viewed in the direction of arrows AA in FIG. 1 and a diagram showing a fluid converter together with a connection relation thereof.

FIG. 3 is a side view showing a state in which a working device is connected to a working arm via a quick coupler device having a conventional pin connecting structure.

FIG. 4 is a cross-sectional view as seen in the direction of arrows BB in FIG. 3;

[Explanation of symbols]

 6c: arm (one member) 6e: bucket (the other member) 8: connecting pin structure 12: pin 14: fluid pressure source 16: fluid converter 16b: piston (isolation member) 30: fluid chamber (of fluid pressure source) Fluid is connected) 32: Fluid chamber (fluid that moves and operates the pin is connected)

Claims (2)

[Claims] 1. A pin slidably disposed on one member, and a fluid converter interposed between the pin and a fluid pressure source of a work machine, wherein the pin has a distal end that is Moving between a `` protruding position '' projecting from one member and passing through the other member and a `` retracted position '' retracting into the one member to removably connect the other member to the one member, The fluid converter includes a fluid chamber to which the fluid of the fluid pressure source is connected, and a fluid chamber to which the fluid that moves and operates the pin is connected.
A separating member for movably isolating between the two fluid chambers to enable transmission of fluid pressure between the two fluids. 2. The connecting pin structure for a working machine according to claim 1, wherein the fluid for moving the pin has a higher viscosity than the fluid of the fluid pressure source.