JPH0643252Y2 - Seal structure around the rotary joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a seal structure around a rotary joint, and more specifically, between a rotary joint and a swing table provided at the center of a turning device in a construction machine or the like. The present invention relates to a seal structure for sealing

(Conventional technology and its drawbacks) In construction machines such as hydraulic power shovels, the swinging device allows the upper swing body to freely swing with respect to the lower traveling body. A rotary joint is provided for transmitting the generated energy to the undercarriage by hydraulic oil.

FIG. 3 shows a structure of a turning device of a hydraulic power shovel incorporating such a rotary joint, and FIG. 4 shows details of a sealing structure around the rotary joint. The revolving device includes an oil motor 3 and a revolving speed reducer 5 provided on a swing table 1 of an upper revolving structure, and a pinion 7 of the revolving speed reducing device rotates a ring gear 11 fixed to a car body 9 on the lower traveling structure side. And the swing table 1 rotates relative to the car body 9. At this time, the rotary joint 13 provided on the swing table 1 also rotates relatively to the inside body 17 fixed to the plate 15 on the car body side. In the figure
Reference numeral 19 is a piping port of a rotary joint, 21 is a swing bearing fixed to the swing table 1, and 23 is a grease bath formed by plates 25 and 27 on the car body side.

In such a turning device, a space between the rotary joint 13 and the swing table 1 is provided between the rotary joint 13 and the swing table 1 in order to protect the grease bath 23, which holds the grease for lubricating the pinion 7 and the ring gear 11, from the intrusion of moisture or foreign matter from the outside. Must be sealed. On the other hand, it is difficult to make the center of the inside body 17 on the lower traveling body side and the center of the rotary joint 13 on the upper revolving body side completely coincide with each other because of the limit of the processing accuracy of each component. When 1 turns, it makes an axial displacement relative to the swing table, and this axial displacement must be absorbed. For this reason, conventionally, as shown in FIG. 4, a rubber cover 31 seals between the flange portion 29 of the rotary joint 13 and the swing table 1 to meet these requirements. The rotary joint 1 is fixed in the rotating direction by bolting one end of the fixing plate 33 to the rotary joint 13 as shown in FIG.
35, the long hole 37 provided at the other end of the fixing plate is engaged with a stopper pin 39 provided upright on the swing table to fix the rotary joint in the rotational direction and to cope with the above-mentioned axis deviation motion. .

However, the above-mentioned conventional ones are rotary joints.
In order to seal between 13 and the swing table 1, many parts such as a retainer 41 holding the rubber cover, a cover plate 43, and a bolt 45 are required in addition to the rubber cover 31, so that the structure and assembly are complicated. There are drawbacks.

(Means for Solving the Problems) The present invention has been made to eliminate the above-mentioned conventional drawbacks. Therefore, the present invention is designed to eliminate the problem between the rotary joint and the swing table provided at the center of the turning device. To seal the rotary joint, a peripheral groove is provided on the outer peripheral surface of the flange portion of the rotary joint, and an O-ring is inserted into the peripheral groove.
The outer peripheral portion of the ring is closely attached to the inner peripheral surface of the swing table.

(Operation) The O-ring seals between the outer peripheral portion of the flange of the rotary joint and the inner peripheral surface of the swing table, and prevents moisture and foreign matter from the outside from entering the grease bath through the seal portion. be able to. Further, by appropriately selecting the cross-sectional area of the O-ring, the hardness, and the tightening allowance, the seal can be maintained even if the rotary joint undergoes an axial displacement motion. In the present invention, the structure and the assembly can be simplified because only the rotary joint in which the O-ring is previously installed in the peripheral groove is inserted into the inner peripheral surface of the swing table.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

1 and 2 show an embodiment in which the present invention is applied to a turning device of a hydraulic excavator, and the same reference numerals as those in FIGS. 3 to 5 denote the same components. In this embodiment, a peripheral groove 47 is provided on the outer peripheral surface of the flange portion 29 'of the rotary joint 13, and an O-ring 49 is inserted into the peripheral groove,
The outer peripheral surface of the O-ring is the inner peripheral surface 51 of the swing table 1.
It is in close contact with. Further, a protrusion 55 having a cutout groove 53 is provided in a part of the outer peripheral portion of the flange portion 29 ', and the cutout groove 53 is provided.
Are engaged with stopper pins 57 provided upright on the swing table 1, respectively.

With the O-ring 49, it is possible to prevent moisture, foreign matter, and the like from entering the grease bath from the outside through the gap between the rotary joint 13 and the swing table 1. It should be noted that the rotary joint 13 causes an axial displacement motion due to the turning of the swing table 1, but the axial displacement amount can be suppressed appropriately if the assembling precision of each component is appropriately selected. Also, in this type of turning device, the turning speed is at most about 20 rpm. Therefore, if the cross-sectional area of the O-ring 49, the hardness of the rubber, and the tightening margin of the O-ring are selected to some extent, the O-ring seal can be maintained even if the above-mentioned axis deviation occurs.

Further, the rotary joint 13 can be fixed in the rotational direction by the engagement of the notch groove 53 and the stopper pin 57, and at the same time, the axial displacement movement can be absorbed.
The means for fixing the rotary joint in the direction of rotation is
Instead of the one of this embodiment, a conventional structure using the fixing plate can be used.

The seal structure having such a structure is extremely simple in structure since the only component provided between the rotary joint 13 and the swing table 1 is the O-ring 49, and the O-ring is provided with the circumferential groove 47 in advance. Since it is only inserted into the inner peripheral surface of the swing table 1 that is assembled in, it is easy to assemble, and therefore can be manufactured at low cost. Further, when the rotating direction fixing means of the rotary joint 13 of this embodiment is used, the structure and assembly can be simplified as compared with the conventional fixing means.

It should be noted that although the above embodiment has been described in connection with the turning device of the hydraulic excavator, the present invention is not limited to this, and may be applied to a seal structure of a turning device such as a truck crane, a turning crane, and a sightseeing machine. You can

(Effect) As described above, according to the present invention, it is possible to obtain the seal structure around the rotary joint of the swivel device, which is easy to structure and assemble, and can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a sectional view of a seal structure around a rotary joint according to an embodiment of the present invention, FIG. 2 is a plan view of the rotary joint of FIG. 1, and FIG. 3 is a sectional view of a turning device including a conventional rotary joint. 4 is an enlarged sectional view showing the seal structure around the rotary joint of FIG. 3, and FIG. 5 is a plan view of the rotary joint of FIG.

Claims (2)

[Scope of utility model registration request] 1. In a turning device having a swing table and a rotary joint provided at a turning center of the swing table, in order to seal between the rotary joint and the swing table, an outer peripheral surface of a flange portion of the rotary joint is sealed. A seal structure around a rotary joint, wherein a peripheral groove is provided, an O-ring is inserted into the peripheral groove, and an outer peripheral portion of the O-ring is brought into close contact with an inner peripheral surface of a swing table. 2. The rotary joint is provided with a protrusion having a notch groove on an outer peripheral portion of the flange portion, and the notch groove is engaged with a stopper pin erected on the swing table. The seal structure according to item 1.