JPH0724438Y2 - Backhoe swivel joint lubrication structure - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backhoe swivel joint lubrication structure.

[0002]

2. Description of the Related Art Conventionally, in a backhoe, a body frame equipped with a prime mover is pivotally mounted on a turning base provided on a traveling section so as to be able to turn left and right via a turntable. A swivel joint is installed between the bases to allow the hydraulic fluid to flow between them. It is inserted into the upright bottom closed tubular outer, and the inner and outer communication grooves are designed to allow the working oil to flow without any problems regardless of the rotation of the rotating table. The sliding surface is in sliding contact with a very small gap, and an O-ring is provided between the sliding surface and the flow groove to prevent leakage of hydraulic oil.

[0003]

Therefore, friction acts on the sliding contact surface each time the turntable turns, but the O-ring causes the inflow of hydraulic oil to the sliding surface near the open end of the outer. Since it was blocked, there was a risk of seizure.

[0004]

According to the present invention, a lower end closed cylindrical outer member is provided between a swivel base erected on a traveling frame and a rotary base pivotally supported on the base so as to be rotatable left and right. ,
Inside the outer, a swivel joint consisting of a substantially columnar inner inserted from above is installed vertically on the lower surface of the turntable via the inner, and the outer is connected to the swivel base to make sliding contact between the outer and the inner. The communication groove formed on each surface allows the working oil to flow between the inner and outer parts, and the upper and lower ring grooves are provided on the sliding contact surface near the open upper end of the outer member with a predetermined interval. Formed, fit O-rings into each ring groove, and
A drain hole communicating with the hydraulic oil tank is provided in the inner part, and an oil hole is provided toward the outer circumference from the drain hole, while the oil hole is formed between the ring grooves and in the sliding contact surface on the outer side. In a corresponding position, a circumferential oil groove is formed over the entire circumference, and the oil groove and the drain hole are connected to each other through the oil hole, and are related to a swivel joint lubrication structure of a backhoe. .

[0005]

[Function] Since no oil pressure is applied to the drain oil circuit,
Only the hydraulic oil necessary for lubrication is allowed to flow in without excessive hydraulic pressure being applied to the sliding contact surface. Conversely, even if the operating oil leaks to the sliding contact surface due to O-ring failure, etc. Since the hydraulic oil is communicated with the drain oil circuit, the leaked hydraulic oil is returned to the hydraulic oil tank and collected to prevent the hydraulic oil from flowing out from the outer open end.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described in detail with reference to the drawings. A indicates a backhoe, and a crawler 1 as a traveling unit.
A swivel base 3 is erected at a substantially central portion of a traveling frame 2 equipped with a vehicle frame 5, and a body frame 5 is pivotally mounted on the base 3 via a rotary table 4 so that the machine frame 5 can be swiveled left and right. A prime mover section 6 is arranged in the rear part, a driving section 7 is arranged in the central part,
A boom, an arm, and a bucket 9, 10, 11 are sequentially arranged from the rear via a boom support 8 provided at the center of the front end of the frame 5.
Hydraulic cylinders 9 ', 1 which are connected to each other by pivot
The excavation work is configured to be rotated up and down by the operation of 0'and 11 '.

In the traveling section, hydraulic motors 12 and 12 'as a pair of left and right hydraulic actuators for driving the crawler 1 are provided.
Is provided, and a hydraulic cylinder 14 as a hydraulic actuator for raising and lowering the soil discharge plate 13 provided in front of the turning base 3 is provided, and the three hydraulic actuators 12, 12 ', Reference numeral 14 denotes a hydraulic pump 12, which is disposed in the prime mover section 6, and a hydraulic actuator 12, 1 via a control valve 16.
It is driven by the hydraulic oil that is supplied to the hydraulic oil tanks 2 ′ and 14 and then flows back to the hydraulic oil tank 17, and the control valve 16 on the rotary base 4 side
Further, a swivel joint J is provided between the hydraulic oil tank 17 and the hydraulic actuators 12, 12 ', 14 on the side of the swivel base 3 to allow the hydraulic oil to flow even if the rotary table 4 rotates. .

In the joint J, as shown in FIG. 3, a cylindrical outer casing 18 having a closed lower end is erected on the swivel base 3, and the outer peripheral surface of the outer casing 18 is connected to the hydraulic actuators 12, 12 ', 14 from the hydraulic actuators 12, 12', 14. Six hydraulic pipes 20 are connected for reciprocation,
Six hydraulic hoses 21 corresponding to the hydraulic pipe 20 are connected to the upper outer surface of a substantially columnar inner 19 inserted into the outer 18 from above.
Reference numeral 21 denotes six communication holes 22 formed inside the inner 19 and
The six communicating grooves 25, 26 formed in the sliding contact surfaces 23, 24 of the outer 18 and the inner 19 respectively maintain independent communication states regardless of the rotation of the rotary table 4.

A ring groove 27 is formed on the sliding contact surface 24 of the inner 19 at an intermediate position between the adjacent communication grooves 26.
Sliding contact surface where O-ring 28 is fitted in 27 and is in contact with communication grooves 25, 26
Prevents hydraulic oil from leaking from 23 and 24. In particular, in order to prevent the hydraulic oil from leaking to the outside of the joint J, the sliding contact surface 23 above the uppermost communication groove 25 of the outer 18 is provided with a predetermined distance d and two ring grooves 27 and An O-ring 28 is provided, and a dust-proof O-ring 28 is also provided on the chamfered portion of the outer peripheral edge of the open upper end surface of the outer 18.

On the sliding contact surface 24 at the inner position of the predetermined distance d,
An oil hole 29 is formed from the drain hole 30 toward the outer periphery.The oil hole 29 is formed on the sliding contact surface 23 of the outer 18 in order to discharge the hydraulic oil leaked from the communication holes 25 and 26. The circular oil groove 32 is communicated with the drain hole 30 formed inside the inner 19, and the oil groove 32 is provided at a position corresponding to the oil hole 29. And the drain hole 30 is the inner 19
Is connected to the hydraulic oil tank 17 through a drain hose 31 connected to the upper end surface of the hydraulic oil tank 17. Therefore, the sliding contact surface 24 receives hydraulic pressure from the head h between the liquid surface of the hydraulic oil tank 17 and the swivel joint J. This hydraulic pressure is suitable for lubricating the sliding contact surfaces 23, 24, and it reduces the friction of the sliding contact surfaces 23, 24 to prevent seizure and, in the unlikely event, the O-ring 28 Even if the hydraulic oil leaks due to a defect or the like, the leaked hydraulic oil is the oil groove 32 of the sliding contact surface 23, the oil hole 29 of the sliding contact surface 24, the drain hole 30, and the drain hose.
It is returned to the hydraulic oil tank 17 via 31 and collected, and leakage to the outside of the joint J is prevented. Moreover, since the drain oil can be stored in the oil groove, the oil can be prevented from running out and the seizure of the swivel joint can be prevented more reliably.

[0011]

According to the present invention, since the circumferential oil groove is formed over the entire circumference at the position corresponding to the oil hole provided on the inner side on the sliding contact surface on the outer side, the drain is formed in the oil groove. It has the effect of being able to store oil to prevent oil shortage and to prevent seizure of the swivel joint.

Further, even if the hydraulic oil leaks due to a defective O-ring or the like, it is returned to the hydraulic oil tank via the oil groove, oil hole, drain hole, and drain hose on the sliding surface of the leaked hydraulic oil and the drain hose. This prevents leakage from the swivel joint.

[Brief description of drawings]

FIG. 1 is an overall side view of a backhoe having a swivel joint structure of the present invention.

FIG. 2 is a plan view of the main part.

FIG. 3 is a sectional view taken along line I-I of FIG.

[Explanation of symbols]

 A Backhoe J Swivel joint 2 Travel frame 3 Revolving base 4 Rotating table 17 Hydraulic oil tank 18 Outer 19 Inner 23 Sliding contact surface (outer side) 24 Sliding contact surface (inner side) 25 Communication groove (outer side) 26 Communication groove ( Inner side) 29 Oil hole 30 Drain hole 32 Oil groove

Claims (1)

[Scope of utility model registration request] 1. A swivel base which is erected on a traveling frame (2).
(3) and a turntable pivoted on the same base (3) so that it can swing left and right
(4) Swivel joint (J) consisting of a tubular outer end (18) closed at the lower end and a substantially columnar inner (19) that is fitted into the outer (18) by inserting it from above. Through the inner (19) to the lower surface of the turntable (4), and the outer (18)
To the swivel base (3) to connect the outer (18) and inner (19)
Communication grooves (25), (2) formed on the sliding contact surfaces (23), (24) of
6) allows the hydraulic oil to flow between the inner (19) and the outer (18), and the upper and lower ring grooves (23) on the sliding contact surface (23) near the open upper end of the outer (18). 27), (2
7) are formed at a predetermined interval, and each ring groove (27), (2
Insert O-rings (28) and (28) into 7) respectively , and
A drain that communicates with the hydraulic oil tank (17) inside the inner (19).
Not only the drain hole (30) but also the drain hole (30)
Between the ring grooves (27), (27) while providing an oil hole (29)
And the oil on the sliding contact surface (23) on the outer (18) side
At the position corresponding to the hole (29), a circumferential oil groove (32) is formed all around.
Formed over the same oil groove (32) and the drain hole (30) ,
A backhoe swivel joint lubrication structure in which the oil is communicated through the oil hole (29) .