JPS6322381Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the improvement of a mechanical seal, and more specifically, to always apply an appropriate spring load even if the housing and the rotating shaft are displaced in the axial direction after the mechanical seal is installed. The purpose of the present invention is to provide a mechanical seal configured to perform the following functions.

For example, for devices such as certain types of pumps in which the housing and the rotating shaft inserted into the shaft hole of the housing are slightly displaced in the axial direction during operation, mechanical A seal is attached and used. In other words, 1 indicates (a part of) the housing of the device, 3 indicates (a part of) the rotating shaft inserted into the shaft hole 2 of the housing 1, and the mechanical Seal 4 is attached. 5 is a seal ring which is a rotating and sliding ring that is fitted onto the rotating shaft 3 via a collar 6 and a retaining ring 7 and driven by the rotating shaft 3; 8 is a fixed slide disposed opposite to the seal ring 5; The floating sheet is a moving ring, and a sealing sliding surface is formed at the contact surface between the seal ring 5 and the floating sheet 8. The latter floating seat 8 is fitted onto the tip of a retaining ring 11 that is fitted airtightly and movably in the axial direction to the inner circumferential step of a seal cover 10 that is fixed with bolts 9 to the opening edge of the shaft hole 2 of the housing 1. At the same time, the retaining ring 11 is pressed via the compression ring 15 by a required number of coil springs 14 whose rear ends are held by a case 13 which is secured to the seal cover 10 by bolts 12. , the seal ring 5 follows the axial movement of the seal ring 5 due to the displacement of the rotating shaft 3 with respect to the housing 1. 16, 17 and 18 are each,
The collar 6 and the retaining ring 7, the case 13 and the compression ring 15, and the dowel pin that prevents rotation of the compression ring 15 and the retaining ring 11, 19 is a set screw, and 20 is a packing.

In the conventional seal having the above configuration, even if the rotating shaft 3 is displaced to some extent in the axial direction with respect to the housing 1, the floating seat 8 is not affected by the elasticity of the coil spring 14 against the seal ring 5 fitted to the rotating shaft 3. The seal ring 5 is pressed by the coil spring 14 within the range of the stroke to follow it.
Although there is no possibility that so-called seal failure will occur due to the separation of the floating sheet 8 and the floating sheet 8, since the coil spring 14 expands and contracts in the axial direction to move the floating sheet 8, depending on the situation (displacement). The spring load would fluctuate, and the sealing performance would inevitably become unstable.

The mechanical seal of the present invention has been developed in view of the above points, and allows the current position of the floating sheet after the following movement to be confirmed from outside the housing, as well as to adjust the position of the coil spring according to the position. The end holding position is variable, and the length of the coil spring attached is always kept constant regardless of the situation, so that an appropriate spring load is maintained. For this reason, the mechanical seal of the present invention has a through hole extending in the axial direction in the case that holds the rear end of the coil spring and is attached to the opening edge of the shaft hole of the housing, and a fixing slide is inserted into the through hole. A spring load adjustment mechanism is provided in which a pin of a required length indicating the position of the moving ring is inserted and the mounting position of the case relative to the housing is adjusted in accordance with the position indicated by the pin.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, 21 indicates (a part of) the housing, 23 indicates (a part of) the rotating shaft inserted into the shaft hole 22 of the housing 21, and both 21, 2
A mechanical seal 24 is installed to close the gap between the three. 25 is a sleeve fitted externally to the rotating shaft 23; 27 is a collar fitted on the outer periphery of the sleeve 25; and a seal ring serving as a rotating sliding ring is provided between the collar 27 and the protrusion 26 of the sleeve 25. 28 is fitted. The seal ring 28 follows the movement of the rotating shaft 23. Reference numeral 29 denotes a retaining ring that is fitted to the inner circumferential stepped portion of the housing 21 through an O-ring 30 so as to be airtight and movable in the axial direction.
A floating sheet 31, which is a fixed sliding ring that comes into sliding contact with 8, is fitted. 32 is the retaining ring 29
The compression ring 32 is disposed behind the compression ring and is movable in the axial direction, and a required number of coil springs 34 are elastically mounted between the compression ring 32 and the case 33. The rear end of the coil spring 34 is inserted into a recess 35 formed in the case 33. This coil spring 34 is
The floating sheet 31 is pressed against the seal ring 28 via the compression ring 32 and the retaining ring 29. The case 33 has a substantially L-shaped cross section, and a radial portion 35 having a hole (not shown) is connected to the shaft hole 22 of the housing 21.
Insert into the stud bolt 36 protruding from the edge of the opening,
It is attached to the housing 21 by screwing two hexagonal nuts 37 and 38 onto the tip of the stud bolt 36, and between the end surface 39 of the housing 21 and the inner end surface of the inner hexagonal nut 37. By providing a distance a greater than the thickness b of the radial portion 35, the radial portion 35 can be moved in the axial direction, and by the action of the coil spring 34, the rear end surface 40 is always aligned with the inner end surface of the inner hexagonal nut 37. By changing the screwing position (threading depth) of the hexagonal nuts 37 and 38 with respect to the stud bolt 36, the hexagonal nuts 37 and 38 are moved in accordance with this. Further, the cylindrical portion of the case 33 is provided with a through hole 41 that passes through both end surfaces thereof in the axial direction.
In contrast, the tip of the compression ring 32
A drive pin 43 fixed to is inserted.
The drive pin 43 prevents the compression ring 32 from rotating relative to the case 33, and is provided with a head 44 at its rear end that engages with a step 42 formed in the middle of the through hole 41. In the initial mounting state (as shown in the figure) before the rotating shaft 23 is displaced relative to A predetermined distance c is set between the head 44 and the head 44. The distance c is set to be longer than the predetermined amount of displacement of the rotating shaft 23 relative to the housing 21 toward the left in the figure.

The mechanical seal 24 having the above configuration is installed in the state shown in the figure as described above,
When the rotating shaft 23 is displaced in the axial direction with respect to the housing 21 due to subsequent driving of the equipment, other members 25, 27, 28, 29, except the case 33,
31, 32, and 43 follow this directly or by the action of the coil spring 34, and the amount of displacement is the same as that of the rear end surface 40 of the case 33.
This is expressed as an axial deviation (length) between the drive pin 43 and the rear end surface of the head 44. Therefore, the coil spring 34 is
Case 3 shows that the installation length has been changed.
The rear end surface 40 of 3 is again connected to the head 4 of the drive pin 43.
The coil spring 34 returns to its mounting length by adjusting the screwing position of the hexagonal nuts 37 and 38 to the stud bolt 36 and moving the case 33 in the axial direction so that it is flush with the rear end surface. , it becomes possible to maintain the spring load at the desired design value.

Further, the mechanical seal 24 has a rotating shaft 2 with respect to the housing 21, like a certain type of pump.
3, it is also possible to use the coil spring 34 in such a way that the spring load of the coil spring 34 is always kept constant, regardless of the existence and size of the error, even for equipment where a slight installation error occurs when installing the coil spring 34.

As explained above, the mechanical seal of the present invention is equipped with a spring load adjustment mechanism that detects and adjusts fluctuations in the spring load of the coil spring that presses the fixed sliding ring against the rotating sliding ring, and constantly adjusts the spring load to the design value. The practical effects of the present invention are extremely large, as the sealing performance is maintained in a stable manner and a stable sealing performance is exhibited.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing how a conventional mechanical seal is installed, and FIG. 2 is a sectional view showing how a mechanical seal according to an embodiment of the present invention is installed. 21...Housing, 22...Shaft hole, 23...
Rotating shaft, 24... Mechanical seal, 28... Seal ring, 29... Retaining ring, 31... Floating seat, 32... Compression ring, 33... Case, 34... Coil spring, 36... Stud bolts, 37, 38...hexagonal nuts, 40...rear end surface of the case, 41...through holes, 43...drive pins, 44...head.

Claims (1)

[Scope of utility model registration request] In a mechanical seal installed in a device in which a housing and a rotating shaft inserted into a shaft hole of the housing are displaced in the axial direction, a rotating sliding ring that is fitted on the outer periphery of the rotating shaft and follows the rotating shaft; , a fixed sliding ring fitted into the inner periphery of the shaft hole of the housing so as to be movable in the axial direction; and a fixed sliding ring disposed behind the fixed sliding ring so as to press the fixed sliding ring into contact with the rotating sliding ring. It has a required number of coil springs, a case that holds the rear ends of the coil springs and is attached to the opening edge of the shaft hole of the housing, and a through hole extending in the axial direction is bored in the case. A spring load adjustment mechanism is provided that inserts into the through hole a pin that indicates the position of the fixed sliding ring that follows the displacement of the rotating shaft, and adjusts the mounting position of the case with respect to the housing according to the instruction of the pin. A mechanical seal that is characterized by: