WO2016027669A1

WO2016027669A1 - Liquid leak detection unit

Info

Publication number: WO2016027669A1
Application number: PCT/JP2015/072186
Authority: WO
Inventors: 彰上田; 晃広永野
Original assignee: 日本バルカー工業株式会社
Priority date: 2014-08-22
Filing date: 2015-08-05
Publication date: 2016-02-25
Also published as: JP6296500B2; TWI666433B; CN106662497A; TW201608223A; JP2016045068A

Abstract

An oil leak detection unit (10) is incorporated in a movable shaft (21). The oil leak detection unit (10) comprises: a rod seal (23) that is provided on an outer periphery of the shaft (21) and seals oil in a liquid-side space (60) on the outer periphery of the shaft (21); a deformed dust seal (26) that is provided on the outer periphery of the shaft (21) and that is disposed on the opposite side of the liquid-side space (60) relative to the rod seal (23) in the axial direction of the shaft (21); and an alert transmitting part (40) that transmits an alert due to a rise in pressure between the rod seal (23) and the deformed dust seal (26) when oil has leaked from the rod seal (23). With this configuration, a liquid leak detection unit that accurately recognizes a maintenance timing of a seal material and prevents the occurrence of liquid leaks is provided.

Description

Liquid leak detection unit

The present invention generally relates to a liquid leak detection unit, and more particularly to a liquid leak detection unit assembled to a movable shaft.

Regarding conventional technology for detecting liquid leakage, for example, Japanese Patent Laid-Open No. 2001-349500 discloses a leak detection device for a bellows type expansion tube joint for the purpose of visually confirming whether there is leakage at a glance. (Patent Document 1).

The leak detection device for a bellows type expansion and contraction pipe joint disclosed in Patent Document 1 includes a leak detection path in which a pressure rises when the inner pipe of the bellows type expansion and contraction is damaged, and a pressure in the leak detection path. And pressure detecting means for detecting. The pressure detection means is housed in a casing that communicates with the leak detection path, and pressure-sensitive operation means that operates when the pressure in the leak detection path increases, and the tip projects from the casing by the operation of the pressure-sensitive operation means. And a detection operation element.

JP 2001-349500 A

Some movable shafts used in various devices such as hydraulic cylinders and fluid pumps are assembled with a sealing material to seal liquid on the outer periphery of the shaft. As a characteristic of the sealing material, wear and sag occur with the repeated operation of the shaft, so that the sealing performance gradually decreases. For this reason, periodic maintenance of the sealing material is required.

However, since the sealing material is installed inside the device, the need for maintenance of the sealing material is known only when liquid leaks outside the device. In this case, there is a problem that malfunction of the device or operation stop occurs, and it takes a long time to restore the device (from arrangement of the seal material to replacement). In addition, the liquid may leak to the outside of the device, which may contaminate the external environment.

Therefore, an object of the present invention is to solve the above-described problems, and to provide a liquid leakage detection unit that accurately grasps the maintenance time of the sealing material and prevents the occurrence of liquid leakage.

The liquid leak detection unit according to the present invention is a liquid leak detection unit assembled to a movable shaft. The liquid leakage detection unit is provided on the outer periphery of the shaft, and is provided on the outer periphery of the shaft with a first seal material for sealing liquid in the liquid side space on the outer periphery of the shaft, and is arranged in the axial direction of the shaft. When a liquid leaks from the first sealing material and the second sealing material disposed on the opposite side of the liquid side space with respect to the one sealing material, an alert is generated due to an increase in pressure between the first sealing material and the second sealing material. And an alert sending unit for sending.

According to the liquid leakage detection unit configured in this way, when the liquid leaks from the first sealing material, the leaked liquid is sealed with the second sealing material. At this time, since a pressure increase occurs between the first sealing material and the second sealing material, the alert transmission unit transmits an alert due to the pressure increase. Thereby, it is possible to accurately grasp the maintenance time of the sealing material (first sealing material) and prevent the occurrence of liquid leakage.

Also preferably, the alert sending unit sends a stepwise alert according to the magnitude of the pressure increase.

According to the liquid leak detection unit configured as described above, it is possible to prepare for the maintenance of the first seal material in advance.

Also preferably, the alert transmission unit includes a pin member operable by receiving a pressure of a liquid guided from between the first sealing material and the second sealing material.

According to the liquid leak detection unit configured as described above, it is possible to accurately grasp the maintenance time of the first seal material by confirming the operation of the pin member.

Also preferably, the alert transmission unit includes a lighting unit that is turned on by detecting an increase in pressure between the first sealing material and the second sealing material.

According to the liquid leak detection unit configured as described above, it is possible to accurately grasp the maintenance time of the first seal material by confirming the lighting of the lighting unit.

Also preferably, the alert transmission unit includes a sound generation unit that emits a sound by detecting an increase in pressure between the first sealing material and the second sealing material.

According to the liquid leak detection unit configured in this way, it is possible to accurately grasp the maintenance time of the first seal material by confirming the sound emitted from the sound generation unit.

Also preferably, the alert transmission unit includes a display unit for displaying a pressure between the first sealing material and the second sealing material.

According to the liquid leak detection unit configured as described above, it is possible to accurately grasp the maintenance time of the first seal material by confirming the pressure display on the display unit.

Also preferably, the liquid leak detection unit further includes a relief part that discharges liquid from between the first seal material and the second seal material when the pressure rise exceeds a predetermined value.

According to the liquid leak detection unit configured in this way, it is possible to prevent liquid from leaking outside beyond the limit of sealing by the second seal material.

Also preferably, the liquid leak detection unit further includes a liquid return unit that returns the liquid discharged by the relief unit to the liquid side space or a liquid supply source to the liquid side space.

According to the liquid leak detection unit configured as described above, the liquid discharged by the relief portion can be used again in the liquid side space on the outer periphery of the shaft.

Preferably, an external space is located on the opposite side of the first seal material from the second seal material in the axial direction of the shaft. The second sealing material has a first lip portion for preventing liquid leakage from between the first sealing material and the second sealing material to the external space.

According to the liquid leak detection unit configured in this way, when the liquid leaks from the first seal material, the leaked liquid can be sealed with the second seal material.

Also preferably, the second sealing material further has a second lip portion for preventing dust from entering from the outer space between the first sealing material and the second sealing material.

According to the liquid leak detection unit configured in this way, the intrusion of dust from the external space can be further prevented by the second sealing material.

As described above, according to the present invention, it is possible to provide a liquid leakage detection unit that accurately grasps the maintenance time of the sealing material and prevents the occurrence of liquid leakage.

It is sectional drawing which shows the state which assembled | attached the oil leak detection unit in Embodiment 1 of this invention to the shaft. It is a side view which shows a mode that the alert transmission part in FIG. 1 transmits an alert. It is a side view which shows another mode that the alert transmission part in FIG. 1 transmits an alert. It is a side view which shows another mode that the alert transmission part in FIG. 1 transmits an alert. It is the figure which represented typically the hydraulic circuit of the hydraulic cylinder provided with the shaft in FIG. It is sectional drawing which shows the state which assembled | attached the oil leak detection unit in Embodiment 2 of this invention to the shaft.

Embodiments of the present invention will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

(Embodiment 1)
1 is a cross-sectional view showing a state in which an oil leakage detection unit according to Embodiment 1 of the present invention is assembled to a shaft.

Referring to FIG. 1, oil leak detection unit 10 in the present embodiment is an assembly unit that is assembled to shaft 21. The shaft 21 has a shape extending axially along the central axis 101. The shaft 21 is a movable shaft. In the present embodiment, it is assumed that the shaft 21 is a hydraulic cylinder shaft. The shaft 21 reciprocates in the axial direction of the central axis 101.

A housing 31 is provided on the outer periphery of the shaft 21. The housing 31 has a shape extending in a cylindrical shape in the axial direction of the central shaft 101.

A liquid side space 60 is formed on the outer periphery of the shaft 21. Oil is disposed in the liquid side space 60. The liquid side space 60 is provided as a hydraulic chamber to which oil for operating the shaft 21 is supplied. The liquid side space 60 is provided on one side of the housing 31 in the axial direction of the central shaft 101. An external space 70 is formed on the other side of the housing 31 in the axial direction of the central shaft 101.

The oil leak detection unit 10 in the present embodiment includes a rod seal 23, a deformed dust seal 26, and an alert transmission unit 40.

The rod seal 23 and the irregularly shaped dust seal 26 are closed annular seal materials. The rod seal 23 and the irregular dust seal 26 are made of an elastic member such as rubber. The rod seal 23 and the irregular dust seal 26 are provided on the outer periphery of the shaft 21. The rod seal 23 and the irregular dust seal 26 are provided at a distance in the axial direction of the central shaft 101. In the axial direction of the central shaft 101, the rod seal 23 is provided on the liquid space 60 side, and the irregular dust seal 26 is provided on the external space 70 side.

The shaft 21 has a seal groove 38 and a seal groove 39 formed therein. The seal groove 38 and the seal groove 39 are recessed from the inner peripheral surface 31 b of the housing 31 and have a groove shape that circulates around the central axis 101. The seal groove 38 has a rectangular cross section. The seal groove 39 has a rectangular cross section that is released toward the external space 70 in the axial direction of the central shaft 101.

The rod seal 23 and the irregular dust seal 26 are accommodated in a seal groove 38 and a seal groove 39, respectively. An inter-seal space 65 is formed between the rod seal 23 and the irregular dust seal 26 on the outer periphery of the shaft 21.

The rod seal 23 has a sealing function for sealing the oil disposed in the liquid side space 60.

The deformed dust seal 26 has a lip part 27 (first lip part), a lip part 28 (second lip part), and a base part 29 as its constituent parts. The base 29 is installed in the seal groove 39. The lip portion 27 and the lip portion 28 extend from the base portion 29 toward the shaft 21 and contact the outer peripheral surface 21 a of the shaft 21. In the axial direction of the central shaft 101, the lip portion 27 is provided on the inter-seal space 65 side, and the lip portion 28 is provided on the external space 70 side.

The deformed dust seal 26 has a function of sealing the oil that has entered the inter-seal space 65 from the liquid side space 60 into the inter-seal space 65 when the oil from the rod seal 23 leaks by the lip portion 27. The deformed dust seal 26 further has a function of preventing dust from entering the inter-seal space 65 from the external space 70 by the lip portion 28.

In the present embodiment, the configuration in which the deformed dust seal 26 having both the function of sealing oil and the function of preventing intrusion of dust has been described. However, the present invention is not limited to this configuration, and the oil is sealed. And a sealing material having a function of preventing dust and a sealing material having a function of preventing dust from entering may be provided separately.

The alert transmission unit 40 transmits an alert due to a pressure increase in the space 65 between the seals when the oil disposed in the liquid side space 60 leaks from the rod seal 23.

The alert transmission part 40 has the block 41, the pin member 46, the spring 45, the piping 36, and the piping 37, and these are combined and comprised.

The block 41 is formed from a metal block body. The block 41 is connected to the housing 31 via a pipe 36 and a pipe 37.

The housing 31 is formed with a recess 32 and a through hole 33. The recess 32 and the through hole 33 are formed between the rod seal 23 and the irregular dust seal 26 in the axial direction of the central shaft 101. The recess 32 is recessed from the inner peripheral surface 31 b of the housing 31 and has a shape that rotates around the central axis 101. The through hole 33 extends from the bottom of the recess 32 in the radial direction centered on the central axis 101 and penetrates the housing 31. The through hole 33 communicates with the pipe 36 and the pipe 37. The space between the seals 65 on the housing 31 side and the pin member 46 on the alert transmitter 40 side communicate with each other through the recess 32 and the through hole 33.

The pin member 46 is provided so as to be operable by receiving the pressure of oil guided from the inter-seal space 65 when liquid leaks from the rod seal 23 to the inter-seal space 65.

More specifically, the pin member 46 is supported by the block 41 so as to be able to reciprocate in the axial direction of the central shaft 102. The pin member 46 has a flange portion 48 and a pin tip portion 47 as its constituent parts. The flange portion 48 has a shape that spreads in a hook shape around the central axis 102. The collar portion 48 is guided by the block 41 so as to be movable in the axial direction of the central shaft 101. The flange 48 is provided facing the

pipes

36 and 37. The pin tip portion 47 is provided at the tip of the pin member 46 extending in the axial direction of the central shaft 102 and protrudes from the block 41.

The spring 45 is provided in the block 41 in a state of being contracted in the axial direction of the central shaft 102. The spring 45 applies an elastic force to the pin member 46 in a direction to hold the pin tip portion 47 in the block 41.

FIG. 2 to FIG. 4 are side views showing how the alert sending unit in FIG. 1 sends an alert.

1 to 4, as the shaft 21 repeats reciprocating motion, the rod seal 23 is worn or sag. As a result, oil enters the inter-seal space 65 from the rod seal 23. At this time, the deformed dust seal 26 can prevent the oil that has entered the inter-seal space 65 from leaking into the external space 70.

When the oil leaks from the rod seal 23, the pressure in the space 65 between the seals increases, and the increased pressure acts on the flange portion 48 of the pin member 46. The pin member 46 receives the pressure increase and slides in a direction in which the pin member 46 protrudes further from the block 41 while resisting the elastic force of the spring 45. The user can accurately grasp the replacement timing of the rod seal 23 by confirming the alert transmitted by the alert transmitter 40, that is, the protruding amount of the pin member 46 from the block 41.

In the present embodiment, the alert sending unit 40 sends a stepwise alert according to the magnitude of the pressure increase in the space 65 between the seals.

More specifically, the pin tip portion 47 has a region 47g, a region 47h, and a region 47i arranged in order from the pin tip side in the axial direction of the central shaft 102. The region 47g, the region 47h, and the region 47i are color-coded, and are colored, for example, blue, yellow, and red, respectively.

As shown in FIG. 2, when there is no oil leakage from the rod seal 23, the pin member 46 is in a state in which only the region 47g colored blue projects from the block 41. As shown in FIG. 3, when oil leaks from the rod seal 23, the pin member 46 slides and the yellow colored region 47 h protrudes from the block 41 in the initial stage. As shown in FIG. 4, when oil leakage from the rod seal 23 proceeds, the pin member 46 further slides, so that a region 47 i colored red protrudes from the block 41.

According to such a configuration, the user can prepare in advance for the replacement of the rod seal 23 by confirming the stepwise alert transmitted from the alert transmission unit 40. For example, when only the region 47g protrudes, the state of the rod seal 23 is healthy. When the region 47h protrudes, the replacement rod seal 23 is prepared, and subsequently, the region 47i protrudes. The rod seal 23 is replaced. Thereby, the planned periodic replacement (preventive maintenance) of the rod seal 23 can be executed.

As another example of a step-by-step alert, according to the progress of oil leakage, replacement time (recommended replacement of rod seal 23) → use limit (replacement of rod seal 23 required) → over limit (replacement of rod seal 23) The alert sending unit 40 may be configured to send a step-by-step alert such as “exchange immediately”.

FIG. 5 is a diagram schematically showing a hydraulic circuit of a hydraulic cylinder provided with the shaft in FIG.

Referring to FIG. 5, the hydraulic cylinder 100 includes a cylinder 22 in addition to the shaft 21 and the housing 31. The cylinder 22 has a cylindrical shape extending in the axial direction of the central shaft 101. The shaft 21 is inserted into the cylinder 22. The shaft 21 has a large-diameter portion 21p as its constituent part. The large diameter portion 21p is provided at the tip of the shaft 21. The large diameter portion 21p slides with the inner peripheral surface of the cylinder 22 as the shaft 21 reciprocates.

The hydraulic chamber 51 and the hydraulic chamber 52 corresponding to the liquid side space 60 in FIG. 1 are formed on both sides of the large diameter portion 21p in the axial direction of the central shaft 101. By selectively supplying oil from the oil tank 61 provided with a hydraulic pump to either the hydraulic chamber 51 or the hydraulic chamber 52, the shaft 21 reciprocates in the direction indicated by the arrow 110.

The oil leak detection unit 10 in the present embodiment further includes a relief valve 58 (relief part) and a relief pipe 54 (liquid return part). The relief valve 58 discharges oil from the inter-seal space 65 when the pressure increase due to oil leakage from the rod seal 23 exceeds a predetermined value. The oil discharged by the relief valve 58 is returned to the oil tank 61 through the relief pipe 54.

Such a configuration can prevent the hydraulic cylinder 100 and the oil leak detection unit 10 from being damaged even when the pressure in the space 65 between the seals exceeds the limit pressure for sealing by the irregular dust seal 26.

Note that a relief pipe may be provided so that the oil discharged by the relief valve 58 is directly returned to the hydraulic chamber 51 or the hydraulic chamber 52.

The structure of the oil leak detection unit 10 according to the first embodiment of the present invention described above will be described together. The oil leak detection unit 10 as the liquid leak detection unit according to the present embodiment is attached to the movable shaft 21. Assembled. The oil leak detection unit 10 is provided on the outer periphery of the shaft 21. The rod seal 23 as a first seal material for sealing oil as liquid in the liquid side space 60 on the outer periphery of the shaft 21, and the shaft 21. When the oil leaks from the rod seal 23, the deformed dust seal 26 as a second seal material disposed on the opposite side of the liquid side space 60 with respect to the rod seal 23 in the axial direction of the shaft 21. And an alert transmitter 40 that transmits an alert when the pressure between the rod seal 23 and the irregular dust seal 26 increases.

According to the oil leak detection unit 10 according to Embodiment 1 of the present invention configured as described above, it is possible to accurately grasp the maintenance time of the rod seal 23 and prevent oil leak in the hydraulic cylinder 100. Thereby, in the production line using the hydraulic cylinder 100, the stop of the continuous operation due to the sealing trouble can be eradicated. Moreover, environmental pollution due to oil leakage can be eradicated.

The liquid leak detection unit according to the present invention can be applied to various devices, for example, fluid pumps, continuous production machines, press machines, injection molding machines, industrial robots, hydraulic lifts, tire molding machines, and the like. The The movable shaft to which the liquid leakage detection unit according to the present invention is assembled is not limited to a reciprocating shaft, and may be, for example, a rotating shaft or a shaft that swings in the circumferential direction. A shaft that performs a combination of these movements may be used. The liquid arranged in the liquid side space in the present invention is not limited to hydraulic oil for operating the hydraulic cylinder, and may be, for example, lubricating oil, grease, water, or the like.

(Embodiment 2)
FIG. 6 is a cross-sectional view showing a state in which the oil leakage detection unit according to Embodiment 2 of the present invention is assembled to a shaft. In the present embodiment, various modifications of the alert transmission unit 40 in the first embodiment will be described.

Referring to FIG. 6, the oil leakage detection unit in the present embodiment has an alert transmission unit 80 instead of the alert transmission unit 40 in the first embodiment. The alert transmitter 80 is configured to transmit an alert by a method different from that of the alert transmitter 40 when oil leaks from the rod seal 23.

The alert transmission unit 80 includes a sensor unit (not shown) that detects the pressure in the space 65 between the seals, and a lighting unit (not shown) that lights up when a pressure increase is detected in the sensor unit. The lighting in the lighting unit includes not only continuous lighting but also repeated lighting and extinguishing (flashing).

As another modification, the alert transmitter 80 generates a sensor (not shown) that detects the pressure in the inter-seal space 65, and generates a sound (such as a buzzer or a melody) when a pressure increase is detected in the sensor. And a sound generator (not shown).

As yet another modification, the alert transmitter 80 has a display unit (not shown) that displays the pressure in the space 65 between the seals. As the display unit, for example, a pressure gauge or a digital display of pressure can be used.

Also in these modifications, the alert transmitter 80 may be configured to transmit a stepwise alert according to the magnitude of the pressure increase in the space 65 between the seals. For example, when the alert transmission part 80 has a lighting part, a stepwise alert is realizable by changing the lighting color in a lighting part. When the alert transmission part 80 has a sound generation part, a step-wise alert is realizable by changing the kind of sound emitted.

As shown in FIG. 6, the alert transmission unit 80 is not limited to the form connected to the housing 31, and may be provided at a position away from the device including the shaft 21 such as an operation room of a plant. In this case, a sensor unit for detecting the pressure in the inter-seal space 65 is provided on the device side including the shaft 21, and the operation chamber or the like receives an electrical signal when a pressure increase is detected in the sensor unit. Various mechanisms for sending alerts are provided.

According to the oil leak detection unit according to the second embodiment of the present invention configured as described above, the effects described in the first embodiment can be similarly achieved.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

This invention is used for, for example, a hydraulic cylinder and a fluid pump.

10 Oil leak detection unit, 21 shaft, 21a outer peripheral surface, 21p large diameter portion, 22 cylinder, 23 rod seal, 26 deformed dust seal, 27, 28 lip portion, 29 base, 31 housing, 31b inner peripheral surface, 32 concave portion, 33 Through hole, 36, 37 piping, 38, 39 seal groove, 40, 80 alert transmission part, 41 block, 45 spring, 46 pin member, 47 pin tip part, 47g, 47h, 47i region, 48 collar part, 51, 52 Hydraulic chamber, 54 relief piping, 58 relief valve, 60 liquid side space, 61 oil tank, 65 space between seals, 70 external space, 100 hydraulic cylinder.

Claims

A liquid leak detection unit assembled on a movable shaft,
A first seal member provided on the outer periphery of the shaft, for sealing liquid in a liquid side space on the outer periphery of the shaft;
A second sealing material provided on the outer periphery of the shaft and disposed on the opposite side of the liquid side space with respect to the first sealing material in the axial direction of the shaft;
A liquid leak detection unit comprising: an alert transmission unit configured to transmit an alert due to a pressure increase between the first seal material and the second seal material when liquid leaks from the first seal material.
The liquid leak detection unit according to claim 1, wherein the alert sending unit sends a stepwise alert according to the magnitude of the pressure increase.
The liquid leak detection unit according to claim 1, wherein the alert transmitter includes a pin member operable by receiving a pressure of the liquid guided from between the first seal material and the second seal material.
4. The liquid leakage detection according to claim 1, wherein the alert transmission unit includes a lighting unit that is turned on by detecting a pressure increase between the first sealing material and the second sealing material. 5. unit.
5. The liquid leakage according to claim 1, wherein the alert transmission unit includes a sound generation unit that generates a sound by detecting an increase in pressure between the first sealing material and the second sealing material. Detection unit.
The liquid leak detection unit according to any one of claims 1 to 5, wherein the alert transmission unit includes a display unit that displays a pressure between the first sealing material and the second sealing material.
The liquid leakage according to any one of claims 1 to 6, further comprising a relief part that discharges liquid from between the first sealing material and the second sealing material when the pressure rise exceeds a predetermined value. Detection unit.
The liquid leakage detection unit according to claim 7, further comprising a liquid return unit that returns the liquid discharged by the relief unit to the liquid side space or a liquid supply source to the liquid side space.
An external space is located on the opposite side of the first seal material with respect to the second seal material in the axial direction of the shaft,
9. The device according to claim 1, wherein the second sealing material has a first lip portion for preventing liquid leakage from between the first sealing material and the second sealing material to the external space. The liquid leak detection unit described.
The liquid leak detection according to claim 9, wherein the second seal material further includes a second lip portion for preventing dust from entering between the first seal material and the second seal material from the external space. unit.