JPH0614158Y2 - mechanical seal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a mechanical seal, and more particularly to a mechanical seal having a torque detection jig for detecting friction torque.

[Conventional technology]

The sixth is the conventional method for detecting the friction torque due to sliding.
There is something like the one shown in the figure. Reference numeral (101) in FIG. 6 denotes a motor, and the rotation from the motor (101) is transmitted to the drive shaft (105) via the belt (103). A mechanical seal (107) is attached to the drive shaft (105), and a seal ring as a fixed ring of the mechanical seal (107) is fixed to the housing (111) via a rotatable bearing (109). ing. A shaft (113) is formed at the left end of the housing (111) in the figure, and the housing (111) is supported by bearings (115) and (117) via the shaft (113). Above housing (11
Liquid (119) is enclosed in 1).

Further, the housing (111) has a torque detection leaf spring (121).
The friction torque is detected by measuring a minute deformation of the torque detecting leaf spring (121) with a strain gauge (not shown). Load cell (load cell)
May be used for measurement.

Another method is shown in FIG.
This is measured through the rotary ring of the mechanical seal. Reference numeral (131) in the figure denotes a motor, and this motor (13
The drive shaft (133) rotated by 1) is equipped with a double seal type mechanical seal (135). The mechanical seal (135) is composed of a pair of retainers (137) (137), springs (139) (139), mating rings (141) (141), seal rings (143) (143), and the like.

A torque meter (145) is provided between the motor (131) and the drive shaft (133). The torque is detected by the torque meter (145) via the mating ring (141) as a rotary ring.

In addition to these methods, there is a method of detecting the electric power or current of the driving motor, for example.

[Problems to be solved by the device]

 The above conventional configuration has the following problems.

First, as shown in FIG. 6, there is a case where torque is detected through the fixed ring side. Normally, the housing (111) is equipped with various devices for temperature measurement other than torque detection, such as thermocouples. In addition, the piping for circulating the liquid (119) is attached. Therefore, there is a problem that it is difficult to balance and measurement accuracy is poor.

In addition, a vibration system is configured between the mass (inertia moment) of the rotatable part including the seal ring and the leaf spring (121) for torque detection, so that there is a relatively low natural frequency and the measurement accuracy decreases. There was also the problem of doing.

Further, as shown in FIG. 7, it is the case of detection on the drive side, but the mechanical seal is often used as a double seal type as shown in the figure, and in such a case, the sum of the two is used. Therefore, there is a problem that it is difficult to measure each torque.

In this case also, a vibration system is formed between the torque meter (145) and the moment of inertia of the rotating part of the shaft (133), the rotor of the motor (131), the coupling, etc., and its natural frequency. Therefore, there is a problem that the measurement accuracy decreases.

Further, in a general mechanical device, most of the drive torque is consumed by the load other than the mechanical seal, so if the torque meter (145) is selected according to the diameter of the drive shaft (133),
There is a problem that the sensitivity is insufficient and the measurement accuracy is lowered, and conversely, when the torque meter (145) is selected due to the sensitivity, the rigidity is insufficient.

The present invention has been made based on such a point, and an object thereof is to provide a mechanical seal provided with a mechanism capable of detecting a friction torque with high accuracy.

[Means for Solving the Problems]

In order to achieve the above object, the mechanical seal according to the present invention has a torque detecting jig interposed between a device housing and a fixed ring, and the torque detecting jig is not in contact with the device housing and is fixed. It consists of an annular small-diameter portion that is fitted to the annular side, and a pair of large-diameter portions that are fixed to the equipment housing and are integrated with the small-diameter portion via thin-walled portions that extend in the radial direction at both ends in the circumferential direction. A strain gauge is attached to one side surface of each of the thin portions corresponding to both circumferential end surfaces of the portion.

[Action]

The torque detection jig is fixed to the device housing via a pair of large diameter parts. Further, the four thin-walled portions bridging both ends of the large-diameter portion to the small-diameter portion, the friction torque generated by the close sliding of the rotating ring and the fixed ring is transmitted through the small-diameter portion. The strain gauge detects the deformation in response to the bending torque in the direction, and the deformation according to the friction torque. At this time, since the strain gauges are deformed in opposite directions (expansion on one side and contraction on the other side) at both ends in the circumferential direction of the large diameter portion, the outputs have opposite phases, and the differential detection value is highly accurate. It can be detected.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In this first embodiment, the present invention is applied to an internal flow type (leakage is from the outer periphery of the sealed end face toward the inner periphery) and a rotary type (the elastic member rotates) mechanical seal.

FIG. 1 is a cross-sectional view showing the structure of the mechanical seal according to the present embodiment. In the figure, reference numeral (1) is a shaft and reference numeral
(3) is a device housing. A seal ring (5) is attached to the outer periphery of the shaft (1) as a fixed ring, and this seal ring (5) has a mating ring (7) as a rotary ring.
Are arranged in contact with each other. The mating ring (7) is pressed against the seal ring (5) by an elastic member (not shown). Reference numeral (9) in the figure is an O-ring.

A torque detecting jig (11) is mounted between the seal ring (5) and the device housing (3). As shown in Fig. 2, the torque detecting jig (11) is provided with a large diameter portion at a symmetrical position.
(13) It has (13). This large-diameter portion (13) is formed in the range of 90 °, and the holes (1
5) (15) is formed. The torque detection jig (11) is attached to the equipment housing by the fixing bolt (17) through the hole (15).
It is fixed to (3).

On the other hand, the torque detection jig (11) is formed with small-diameter portions (19) and (19), and these small-diameter portions (19) are in non-contact with the device housing (3) in the radial direction. Further, the small diameter portion (19) is also a device housing in the axial direction as shown in FIG.
Not in contact with (3).

Grooves (21) are formed on the large-diameter portion (13), which is a substantially extended diameter line of the small-diameter portion (19), and holes are formed at both ends of the groove (21).
(23) (23) is formed. With such a configuration, each large-diameter portion (13) has a structure in which both ends in the circumferential direction are integrally bridged with the small-diameter portion (19) through the thin-walled portion (a) extending in the radial direction. Strain gauges (25) are attached to one side surface of each thin portion (a) at positions corresponding to both circumferential end faces of the diameter portion (13). A known torsion torque is applied to these strain gauges (25) for verification. Thereby, the friction torque is quantitatively measured.

According to this embodiment, the following effects can be obtained.

First, as in the case of the conventional method, there is no problem that accuracy is reduced because it is difficult to balance, and there is no problem of accuracy degradation due to configuring the vibration system and having a natural frequency, and highly accurate measurement can be performed. it can. Further, the circumferential friction torque generated by the close sliding of the mating ring (7) and the seal ring (5) acts as the circumferential deformation of the thin portion (a) of the torque detection jig (11). In addition, each large diameter part
The strain gauges (25) and (25) at the positions on both sides of (13) are deformed in the opposite directions to each other, and the outputs have opposite phases, so that highly accurate detection can be performed by the differential detection.

Further, by installing a torque detection jig (11) for each mechanical seal, it is possible to measure each mechanical seal even for a double seal type.

Furthermore, since the O-ring (9) is installed, there is no concern about leakage and the configuration is simple.

Next, second to fourth embodiments will be described with reference to FIGS. First, a second embodiment shown in FIG. 3 is one in which the present invention is applied to an internal flow type static seal (in which an elastic member does not rotate) mechanical seal. An inflow type static mechanical seal (35) is installed between the shaft (31) and the device housing (33), and a torque detection jig (37) is installed on the outer peripheral side of the mechanical seal (35). ing.

Next is a third embodiment, which is an external flow type (leakage goes from the inner circumference to the outer circumference of the sealed end face) as shown in FIG.
Therefore, the present invention is applied to a rotary type mechanical seal. An external flow type rotary mechanical seal (45) is mounted between the shaft (41) and the device housing (43), and the mechanical seal (45) and the device housing (4
A torque detecting jig (47) is attached between the above and 3).

Further, in the fourth embodiment, as shown in FIG. 5, the present invention is applied to an external flow type static mechanical seal. An external flow type static mechanical seal (55) is mounted between the shaft (51) and the device housing (53), and between the mechanical seal (55) and the device housing (53). Is equipped with a torque detection jig (57).

The torque detecting jigs (37), (47) and (57) in the second to fourth embodiments are the torque detecting jigs of the first embodiment.
Since it is the same as (11), the same effect as in the case of the first embodiment can be obtained.

[Effect of device]

As described above in detail, according to the mechanical seal of the present invention, the friction torque can be measured with high accuracy with a simple structure without damaging the original function of the mechanical seal.

[Brief description of drawings]

1 and 2 are views showing a first embodiment of the present invention,
1 is a half sectional view of a mechanical seal, FIG. 2 is a plan view of a torque detecting jig, FIG. 3 is a half sectional view of a mechanical seal according to a second embodiment, and FIG. 4 is a third embodiment. FIG. 5 is a half sectional view of a mechanical seal according to FIG. 5, FIG. 5 is a half sectional view of a mechanical seal according to a fourth embodiment, and FIGS. 6 and 7 are sectional views showing a conventional friction torque detecting method. (1) Shaft, (3) Equipment housing (5) Seal ring (fixed ring) (7) Mating ring (rotary ring) (11) Torque detection jig, (13) Large diameter part (19) Small diameter part, (21) Groove (notch) (25) Strain sensor (sensor for torque detection)

Claims (1)

[Scope of utility model registration request] 1. A fixed ring, a rotary ring, which is mounted in a shaft hole formed in an equipment housing between the shaft and the equipment housing, and abuts on the fixed ring, the fixed ring or the rotary ring. In a mechanical seal including an elastic member that applies an axial load to press the fixed ring and the rotary ring into pressure contact with each other, and a shaft packing, a torque detection jig is interposed between the device housing and the fixed ring. The torque detection jig has a small diameter part that is in non-contact with the equipment housing and is fitted to the fixed ring side, and a thin part that is fixed to the equipment housing and has circumferential ends that extend in the radial direction. A mechanical seal comprising a pair of large-diameter portions integrated with a portion, and a strain gauge is attached to one side surface of each of the thin-walled portions corresponding to both circumferential end faces of the large-diameter portion.