Sealing device

Abstract

A sealing device comprising an intermediate bushing, which is located between an outer sleeve and an inner member mounted therein so as to be movable relative thereto and which forms a gap seal, is designed in such a way that chambers that can be filled with a pressurized fluid are provided between the intermediate bushing and the adjacent outer sleeve.

Claims

1. A sealing device, comprising an intermediate bushing arranged concentrically between an outer sleeve and an inner body and movable relative thereto, the intermediate bushing and the inner body defining a single annular gap therebetween, the bushing cooperating with the outer sleeve the inner body, and a plurality of seals disposed between the outer sleeve and the intermediate bushing to define a plurality of chambers which can be filled with a pressurized liquid, the annular gap simultaneously in fluid communication with all of the plurality of chambers.

2. A sealing device according to claim 1, wherein the intermediate bushing comprises radially oriented through-openings which open into the chambers.

3. A sealing device according to claim 1, wherein each chamber is assigned at least one through-opening.

4. A sealing device according to claim 1, wherein each chamber is designed as a circumferential annular space.

5. A sealing device according to claim 1, wherein several chambers are provided which are distributed over the circumference.

6. A sealing device according to claim 1, wherein the outer sleeve is rotatable or axially displaceable relative to the inner body.

7. A sealing device according to claim 1, wherein the seal comprises a sealing ring, which is supported on the inner wall of the outer sleeve and on the intermediate bushing.

8. A sealing device according to claim 7, wherein the sealing ring is held in a holder.

9. A sealing device according to claim 1, further comprising rings resting against the inner wall of the outer sleeve thereby defining the chambers.

10. A sealing device according to claim 1, the intermediate bushing defining groove-like indentations defining the chambers, which indentations are delimited in the axial direction of the intermediate bushing by the integrally formed holders.

11. A sealing device according to claim 1 wherein the chambers are connected to a pump operable to supply a pressurized fluid thereto.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a sealing device according to the prior art in a longitudinal sectional view;

(2) FIG. 2 shows a rotary device provided with a sealing device according to the present disclosure in a longitudinal sectional view;

(3) FIG. 3 shows a detail of the rotary drive, likewise in a longitudinal sectional view;

(4) FIG. 4 shows an enlarged view of a section of the detail according to FIG. 3 as a longitudinal sectional view;

(5) FIG. 5 shows a further enlarged view of the section according to FIG. 4;

(6) FIG. 6 shows a further embodiment of the invention, likewise in a longitudinal sectional view.

DETAIL DESCRIPTION OF THE DRAWINGS

(7) FIG. 1 shows a sealing device according to the prior art, having an inner body 6 designed as a sleeve, an intermediate bushing 8 which surrounds the latter and is mounted in an outer sleeve 7 by forming a gap seal, wherein an annular gap 15 is formed between the inner body 6 and the intermediate bushing 8. With this design, the pressure of the fluid to be sealed causes the sleeve to widen, resulting in increased leakage.

(8) FIG. 2 shows an electric rotary drive for a hydraulic tool, having a housing 1, a stator 2 mounted therein in a rotationally fixed manner, and a rotor 3 in which the outer sleeve 7 is held in a rotationally fixed manner, through which a fluid under high pressure (>2000 bar) can be supplied via a fluid connection 4.

(9) The outer sleeve 7 is a component of the sealing device 5 according to the invention, which can be seen more clearly in FIGS. 3-6 in enlarged view.

(10) The inner body 6, which is mounted in the outer sleeve 7 and is movable relative to the outer sleeve 7, is arranged in axial alignment with the outer sleeve 7 as a further component of the sealing device 5, i.e., in the example, the inner body 6, which is embodied as an axially consistently open-ended sleeve, is connected in a rotationally fixed manner to the fluid connection 4 and thus to the housing 1, while the outer sleeve 7 is rotatable in relation thereto.

(11) The intermediate bushing 8 is arranged between the outer sleeve 7 and the inner body 6 to form a gap seal, wherein the intermediate bushing 8 may be made of a stainless steel or another suitable material, e.g. ceramics or the like.

(12) According to the invention, chambers 9 are formed between the intermediate bushing 8 and the outer sleeve and are laterally delimited by seals 11, wherein a seal 11 is embodied as a sealing ring 13, for example an O-ring, which is held by a holder 12.

(13) Furthermore, the intermediate bushing 8 has radially or obliquely oriented through-openings 10, which, starting from a formed annular gap 15 between the inner body 6 and the intermediate bush 8, opens into one of the chambers 10. This can be seen particularly clearly in FIGS. 4 and 5.

(14) For the formation of the chambers, rings 14 are provided which are shown in FIGS. 3-5 and rest against the wall of the outer sleeve 7 and are dimensioned such that their inner diameter is greater than the outer diameter of the intermediate bushing 8, so that the chambers 9 are formed between the rings 14 and the intermediate bushing 8. In this case, the respective seal 11 rests both on the wall of the outer sleeve 7 and on the intermediate bushing 8.

(15) A further variant for the formation of the chambers 9 is shown in FIG. 6. In the absence of the rings 14, the intermediate bushing 8 is provided with groove-like indentations, through which the chambers 9 are formed in cooperation with the wall of the outer sleeve 7. In this case, the holders 12 of the seals 11 are in the form of an integral part with the intermediate bushing 8, which rest against the inner wall of the outer sleeve 7.

(16) In the example, the chambers are circumferentially guided, i.e. they form an annular space. However, it is also conceivable to provide a plurality of chambers 9 in the circumferential direction, wherein in each case at least one through-opening 10 opens into the respective chamber 9.

(17) Instead of a rotational relative movement between the outer sleeve 7 and the inner body 6, as is the case for the rotary drive shown in the example, the relative movement can also take place axially, wherein in this case the inner body 6 can also be formed from a solid material, for example a shaft or rod.

(18) The sealing device can be implemented both with an axially or rotatably movable outer sleeve 7 and a fixed inner body 8 as well as with an axially or rotatably movable inner body 8 and an outer sleeve 7 which stands rigidly thereto.