FI72583B - GLIDRINGSTAETNING. - Google Patents

Description

Slip ring seal 1 72583

The invention relates to a slip ring seal comprising a slip ring fixed to a body part, the body part being fastened to e.g. a rotating shaft by means of an element of elastic material arranged between the shaft and the body part.

Such mechanical seals are most commonly used today. for sealing the through-10 path of pump and fan shafts. In this case, the space between the rotating shaft and the housing of the stationary device is sealed by rotating sliding rings which press against each other.

The structure according to the invention relates either to the sealing part rotating with the shaft and to the for the transfer of torque between the sealing part and the axle-15 or to the static sealing part.

In the constructions used today, the fastening of the mechanical seal to the rotating shaft and the torque transmission are realized either by means of tightening screws or by separate torque transmission pins. In the past, rubber joints have also been used, e.g. an O-ring-based structure in which the sealing part is attached to the O-ring. However, the sealing member attached to the O-ring easily slides, as the torque transfer capacity of such a structure is very limited. Separate torque transfer pins have been used to prevent slipping, the purpose of which has been to get rid of the structure utilizing the fastening screws and the torque transfer pin and still provide a structure with sufficient torque transfer capacity. Em.

However, the weakness of the solution is the minimally complex and at the same time expensive structure, i.e. the same drawbacks as the structure utilizing tightening screws and separate torque transfer pins.

The object of the invention is to provide a slip ring-35 seal which does not have the disadvantages of the previously used solutions. This is achieved by means of a slip ring seal according to the invention, characterized in that the compressive force of the element or part thereof of elastic material against the machine part is adapted to increase by compression-increasing deformation of the element or part thereof.

The advantage of the mechanical seal according to the invention is its simple structure, whereby the manufacturing costs 10 are very low. The solution according to the invention has all the advantages of a rubber joint and, in addition, the invention provides a torque transfer capacity which is considerably higher than that of previously used O-ring or other rubber joints. In addition, the structure according to the invention is very durable, so that the structure according to the invention is also very advantageous in terms of operating costs.

The invention will now be explained in more detail by means of some preferred embodiments of the invention shown in the accompanying drawing, in which Fig. 1 shows a mechanical seal according to the invention in a side view, Fig. 2 shows a part of a flexible element used in the structure of Fig. 1 Fig. 1 is a sectional view taken along line III-III, Fig. 4 shows a sectional view according to Fig. 3 in use, Fig. 5 shows in principle the operation of a detail of the structure according to Figs. 1-4 in use, Fig. 6 shows another preferred embodiment of the invention in side view and Fig. 7 shows a third preferred embodiment of the invention in an axial sectional view.

Figure 1 shows in principle a preferred embodiment of a mechanical seal according to the invention.

3,72583

Figure 1 does not show a stationary sealing ring at all, as it is obvious to a person skilled in the art that the stationary sealing ring is placed so that the sliding rings face each other. Em. the facts are known to a person skilled in the art, so that the no further details are provided in this context.

In Fig. 1, the rotating machine part is denoted by the reference number 1. The Liu ring of the sealing ring attached to the machine part is denoted by the reference number 2. The slip ring 2 10 is fixed to the body part 3 by means of a resilient element 4.

Em. a sealing ring formed of the elements 2, 3, 4 is attached to the machine part 1 by means of an element 5 of elastic material. The sealing ring is further supported in the axial direction by means of a suitable component 6, e.g. a running-15 wheel hub.

Figure 2 shows in principle a part of an element 5 of flexible material used in a mechanical seal according to the invention. A plurality of grooves 8 in the direction of the machine part 1 are formed in the element 5, which are separated from each other by means of bases 7. Figure 2 also shows the sealing surface 9.

The basic idea of the solution according to the invention is that by means of the same flexible element both compaction and a sufficiently efficient torque transfer are achieved. Em. operation 25 is implemented by means of the structure according to Figures 1 and 2.

In the following, the operation of the invention will be examined in more detail with the aid of Figures 3-5.

Fig. 3 shows a section along the line III-III in Fig. 1, in which Fig. 3 also shows the brackets 7 and grooves 8, which are also blocked in Fig. 2. Fig. 3 clearly shows the position of the brackets 7 and grooves 8 in the machine part 1 and the frame. between part 3. The situation in Figure 3 shows the situation in the rest state, i.e. in the state in which the machine part 1 does not rotate. In Figure 4, point 3 is shown in Figure 35 instead of in a situation in which the machine part 1 rotates in the direction of the arrow.

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An essential aspect of the invention is that the compressive force of the element of flexible material against the machine part increases. The increase in the compressive force is based on the deformation which increases the compression of the element 5 as a result of the relative movement 5 between the outer surface of the machine part 1 and the inner surface of the element 5. Em. the relative movement occurs when the sealing surface 9 of the element 5 starts to slip on the surface of the machine part 1. Such a slip situation is shown in Fig. 4, from which it can be seen that the shape 10 of the bases 7 changes from a square (Fig. 3) to a diamond. Figure 5 shows in principle the cross-section of one base in the rest position with solid lines and, respectively, with broken lines in the operating situation when the element 5 slips. It can be seen from Figure 5 that the diagonal L of the dormant base 15 decreases in use to be the diagonal L '. Em. for this reason, the compressive force against the shaft increases strongly as the compression of the elastic material increases.

If the elastic element is a part according to Fig. 2, then the above-mentioned deformation takes place as a result of the rotation around the longitudinal axes of the pins 20 between the grooves 8. As the element 5 slides, the bases 5 rotate and at the same time they are compressed as shown in Fig. 5. In this case, the compressive force against the machine part 1 increases and the torque transfer capacity increases.

The grooves 8 can be formed shorter in the longitudinal direction than the width in the direction of the machine part 1 of the element 5. Such an embodiment is shown in Figure 3. However, the grooves 8 can also be adapted to extend to one edge of the element, the sealing surface being only at the other edge of the element 5. The grooves 8 can be formed as openings extending through the element 5 or alternatively as recesses formed in the inner surface of the element, as shown in Fig. 7.

The compression-increasing deformation can also be realized 35 differently from Figures 1 to 5 and 7. Figure 6 shows another preferred embodiment of the invention.

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In Fig. 6, the slip ring is denoted by reference numeral 2 '. The slide ring 2 'is attached to the body part 3' by means of a resilient element 4 '. The element of elastic material to be fitted between the machine part 1 and the body part 3 'is formed in this embodiment 5 from two parts 5' and 10. part 5 'can be e.g. a truncated O-ring and part 10 a normal 0-ring. The O-ring 10 then provides a seal and the severed O-ring 5 'increases the compressive force.

The operation of the embodiment according to Fig. 6 is essentially as follows. Due to the relative movement between the body part 3 'and the machine part 1 (not shown in Fig. 6), the end of the severed O-ring 5' in which direction the shaft rotates, turns obliquely and in a way overturns and thus causes a higher than normal compression pressure on the shaft, i.

The truncated O-ring 5 'works in exactly the same way as the brackets 7. The effect of one break on the increase in torque transmission capacity is about 10%.

The above embodiments are not intended to limit the invention in any way, but the invention 20 may be modified in many different ways within the scope of the claims. Thus, the mechanical seal or parts thereof according to the invention do not necessarily have to be exactly as shown in the figures, but other solutions can also be used. For example, the cross-section of the bases need not be square, but other shapes may be used. The material of the element of elastic material can be, for example, rubber, plastic or a mixture thereof, etc. In addition, it is clear that the number of truncated O-rings is by no means limited, but several such rings can also be used. It is also possible to make several breaks in the severed O-ring and thus to increase the torque transfer capacity. The seal can be attached to the device either by an inner circumference to the shaft or by an outer circumference to the device. The elastic element can also act as a seal and a torque transmitter between the slip ring and the body.

Claims (6)

6 72583 A mechanical seal comprising a mechanical ring (2, 2 ') fixed to the body part (3, 3') / wherein the body part 5 is fixed to either a rotating or non-rotating machine part (1) by means of an element of elastic material interposed therebetween , characterized in that the compressive force of the elastic material element (5) or part thereof (5 ') against the machine part (1) is adapted to increase by means of a compression-increasing deformation of the element (5) or part thereof (51) resulting from relative circumferential movement therebetween . Slip ring seal according to Claim 1, characterized in that the compression-increasing deformation 15 is adapted to occur as a result of the rotation about the longitudinal axes of the bases (7) between the elongate grooves (8) in the machine part (1) formed at regular intervals. Slip ring seal according to Claim 2, characterized in that the grooves (8) are openings extending through the element (5). Slip ring seal according to Claim 2, characterized in that the grooves (8) are recesses formed in the inner surface of the element (5). Slip ring seal according to Claim 3 or 4, characterized in that the grooves (8) extend to the second edge of the element (5). Slip ring seal according to Claim 1, characterized in that the element (5 ', 10) of elastic material 30 comprises at least one truncated O-ring (5') and that the compression-increasing deformation is adapted to occur in the truncated O-ring (51). as a result of the turning of the head at the break point.