JPH027289Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a pin connection structure between a male member and a female member in a construction machine or the like.

Figure 1 shows an example of a hydraulic excavator, in which a boom 2 is supported by a foot pin at the front of the excavator body 1 so that it can be raised and lowered, and a pin is attached to the tip of the boom so that an arm 3 can swing up and down. A bucket bag 4 is rotatably supported at the tip of the arm 3 by a pin.

Next, a conventional pin connection structure between the arm 3 and bucket belt 4 will be explained with reference to FIG.

Bushes 6 are fitted into both ends of the bearing part (male member) 3a of the arm 3, and bushes 8 are fitted into the bearing part (female member) 4a of the bucket bag 4. The bearing portion 3a and the bearing portion 4a are coupled to each other by a pin 5 rotatably inserted into the bushes 8 and 6. Dust seals 7 are press-fitted into the outer ends of the bearing parts 3a, and dust seals 9 are press-fitted into the outer ends of the bearing parts 4a, so that the bearing parts 3a and 4a are opposed to each other. An O-ring seal 10 is installed on the outer periphery of the end face to prevent dirt from entering the gap G between the two.
is installed.

A grease nipple 11 is attached to the end face of the pin 5, and the grease nipple 11 is
The sliding contact between the bushes 6 and 8 and the pin 5 is achieved through a greasing hole 12 provided in the axial direction of the pin 5, a greasing hole 13 provided in the radial direction, and a greasing groove 14 provided on the outer peripheral surface of the pin 5. It leads to the moving surface section. A stopper 1 is attached to the end of the pin 5 and is removable with a bolt 17.
5 is fixed, and the stopper 15 is provided with a grease nipple mounting hole 16 in which the grease nipple 11 is accommodated. Stopper 15 and bearing part 4
There is a minimum gap W between the end faces of a and
is formed. The stopper 15 restricts the movement of the pin 5 in the axial direction beyond the gap W.

In this pin-coupled structure, when the bucket 4 is rotated relative to the arm 3 during excavation, the pin 5 rotates and slides on both the bushes 6 and 8. In this case, the pin 5 receives an external force in the right or left axial direction from the excavated object, etc., and the gap W becomes zero, that is, the inner end surface 15a of the stopper 15 and the bearing part 4
The bucket 4 rotates in a state where the outer end surface 18 of the inner end surface 15a is in pressure contact with the outer end surface 18, and the inner end surface 15a and the outer end surface 18 frequently slide. At this time, torque is generated in the stopper 15, and a shearing force is applied to the bolt 17, which may cause the bolt 17 to loosen and fall off, or to break, leading to an accident in which the pin 5 may come off. In addition, the inner end surface 15 is often
Since a and the outer end surface 18 slide, both wear out quickly, damaging the dust seal 9 and damaging the pin 5.
If earth and sand enters the sliding surface between the pin and the bush 8, and even enters the gap G, all the sliding surfaces of the pin joint will quickly become abnormally worn.

This idea was made to solve the above-mentioned problems, and provides a pin connection structure that can prevent bolts from loosening, dust seals from breaking, pins from falling out, etc. even when a thrust load is applied to the retaining stopper. The purpose is to

In order to achieve this purpose, this invention involves fitting bushes into the male and female members, inserting a pin connecting the two members into the bushings, installing a dust seal between the female member and the pin, and inserting a pin into the bush to connect the two members. A retaining stopper that restricts axial movement is removably fixed to the end, and a grease nipple is attached to both ends of the pin, and a greasing path is connected to the grease nipple between the sliding surfaces of the pin and each bush. In the pin connection structure provided on the pin, an annular recess and a hole for forming a grease reservoir, which has a smaller diameter than the annular recess and is connected to the pin's greasing path and the annular recess, are provided on the outer end surface of the female member, and the pin of the stopper to prevent the pin from falling out is formed. An annular protrusion formed on the end face of the girth is fitted into an annular recess of the female member, and a dust seal is installed between the inner circumferential surface of the annular recess and the outer circumferential surface of the retaining stopper.

An example of this invention is shown below in Figures 4 and 5.
This will be explained using figures. In both figures, the same reference numerals as in FIGS. 2 and 3 represent the same or equivalent items.

An annular recess 19 is provided on the outer end surface of the bearing portion 4a.
A hole 20 is provided which forms a grease reservoir 21 which has a smaller diameter than the annular recess 19 and is connected to the greasing groove 14, and the wall around the hole 20 forms an annular protrusion 22. An annular protrusion 23a is formed on the end surface of the retaining stopper 23 near the pin, and the annular protrusion 23a is fitted into the annular recess 19 of the bearing 4a. A dust seal 24 is attached between the inner peripheral surface of the annular recess 19 and the outer peripheral surface of the stopper 23. The bush 8 is latched by an annular projection 22.

The other configurations are similar to the conventional pin connection structure shown in FIGS. 2 and 3.

In the pin connection structure of this invention, when the bucket 4 is rotated with respect to the arm 3 during excavation, the pin 5 rotates and slides on both the bushes 6 and 8. If an axial load is applied to the pin 5 at this time, the sliding surface between the retaining stopper 23 and the bearing portion 4a is constantly supplied with grease from the grease reservoir 21, so the sliding resistance is small and the stopper is The torque generated at the bolt 17 is extremely small, which reduces wear between the stopper 23 and the bearing 4a, extending the life of both.
It is possible to prevent the pin 5 from loosening and falling off, and furthermore, from coming off.

Although the pin connection structure between the arm 3 and bucket belt 4 has been described as an example of this invention, it goes without saying that this invention can also be applied to the pin connection structure of members in hydraulic excavators and other construction machines. .

As explained above, in the pin joint structure according to this invention, sufficient grease is supplied between each sliding surface and the bearing end surface, so there is less resistance on the sliding surfaces, and wear is prevented, resulting in a long service life. It can be extended significantly. In addition, since a dust seal is provided between the stopper and the annular recess of the bearing, dirt does not enter the inner end face of the stopper, the sliding resistance is small, and no torque is generated in the stopper. No shearing force is applied to the bolt. For this reason,
Bolts will not loosen or break,
This prevents the pin from falling out.

[Brief explanation of drawings]

Fig. 1 is a side view showing an example of a hydraulic excavator, Fig. 2 is a sectional front view showing a conventional pin connection structure, Fig. 3 is a side view showing the retaining stopper and bearing part in Fig. 2, and Fig. 4. 5 is a sectional front view showing one embodiment of this invention, and FIG. 5 is a side view of FIG. 4. 3a... Bearing part (male member), 4a... Bearing part (female member), 5... Pin, 6... Bush, 7...
Dust seal, 8...button, 11...grease nipple, 12...greasing hole, 13...greasing hole,
14... Greasing groove, 15... Removal prevention stopper, 1
7... Bolt, 19... Annular recess, 20... Hole,
21... Grease reservoir, 22... Annular projection, 23
...Keeping stopper, 23a...annular protrusion,
24...Dust seal.

Claims (1)

[Scope of utility model registration request] A bush is fitted into the male member and the female member respectively, a pin connecting the two members is inserted into the bush, a dust seal is installed between the male member and the pin, and a retainer is attached to the end of the pin to restrict movement in the axial direction. In a pin connection structure in which a stopper is removably fixed, a grease nipple is attached to both ends of the pin, and a greasing path is provided on the pin that runs through the grease nipple between the sliding surfaces of the pin and each bush, the female member An annular recess and a hole for forming a grease reservoir, which has a smaller diameter than the annular recess and is connected to the pin greasing path and the annular recess, are provided on the outer end surface, and an annular protrusion formed on the end surface next to the pin of the retaining stopper. A pin connection structure characterized in that a dust seal is fitted into an annular recess of a female member and installed between an inner circumferential surface of the annular recess and an outer circumferential surface of a retaining stopper.