JP2005050690A - Air compressor for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air compressor for a fuel cell prevented from an increase in weight and installation space and from the mixing of lubricating oil into air to be supplied to the fuel cell. <P>SOLUTION: The air compressor sucks air from an air suction port 31 and compresses the air, and exhausts the air from an air exhaustion port 33 by rotations of male and female rotors 5, 7 engaged to each other arranged in an air compression chamber 3. Driving and driven timing gears 25, 20 engaging with each other are fixed to female and male rotor axes 9, 11, respectively, and the respective gears 25, 27 are disposed in an oil chamber 19 and lubricated with the lubricating oil 29. In a separation wall 17 separating the air compression chamber 3 and the oil chamber 19, oil seals 35 are attached to peripheries of the female and male rotor axes 9, 11, and an oil flow path 37 is arranged around the respective rotor axes 9, 11 near to the air compression chamber 3. An oil collecting part 39, a drain valve 41, an outlet side oil collecting part 43, and a drain tap 47 are successively arranged at the lower end of the oil flow path 37. The drain valve 41 is opened simultaneously with the start of operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell air compressor that feeds air into a fuel cell that generates electric power by receiving supply of fuel and air.

  In a fuel cell system, an air compressor for supplying air to a fuel cell contains lubricating oil for lubricating a drive mechanism such as a gear in a casing so that the lubricating oil does not flow to the air discharge side. An oil seal is provided.

  However, if this oil seal breaks for some reason or the amount of leakage from the oil seal increases, lubricating oil will be mixed into the discharge air, and this mixed lubricating oil will be supplied to the fuel cell, causing lubrication. There is a problem that the electrode in the fuel cell is poisoned by poisoning components contained in the oil, and the power generation performance is significantly deteriorated.

As a method for avoiding this problem, for example, there is one described in Patent Document 1 below.
JP, 2001-332285, A This is provided with a switching valve, a bypass passage, and an oil separator between an air compressor and a fuel cell, respectively, and when it is determined that oil leakage has occurred, air compression is performed. In this method, the switching valve is controlled so as to switch the air flow from the machine to the fuel cell from the bypass passage to the oil separator.

  Even if an oil separator is not provided, a filter is provided on the downstream side of the air compressor, and this filter removes dust in the air. If the oil seal of the air compressor is broken, Some have the function of preventing the oil from flowing into the battery.

  By the way, when the above-described filter is provided between the air compressor and the fuel cell, that is, downstream of the air compressor, the filter container can be made of resin on the upstream side. For example, a metal pressure vessel that can withstand high pressure is required.

  A filter using such a pressure vessel increases in weight, and is extremely disadvantageous in terms of fuel consumption and exercise performance when the fuel cell is mounted on a transportation means such as an automobile.

  Further, when the oil separator described above is provided separately, the installation space for the fuel cell system as a whole increases, and the burden increases in terms of cost.

  Accordingly, an object of the present invention is to prevent the mixing of lubricating oil into the air supplied to the fuel cell without causing an increase in weight or an increase in installation space.

  In order to achieve the above object, the present invention provides a lubricating oil for lubricating a drive mechanism unit in a fuel cell air compressor that feeds air into a fuel cell that generates power upon receipt of fuel and air. An oil chamber to be accommodated and a compressed air chamber to accommodate an air compression operating part that is operated by the drive mechanism part are partitioned from each other by a partition, and a connecting part between the drive mechanism part and the air compression operation part corresponding to the partition An oil outflow passage through which the lubricating oil leaking from the oil chamber flows out is provided around the oil outflow passage, and an oil reservoir for storing the outflowing lubricating oil is provided at the lower end of the oil outflow passage.

  According to this invention, the lubricating oil leaking from the oil chamber toward the compressed air chamber flows out into the oil outflow passage and enters the oil reservoir. For this reason, mixing of the lubricating oil into the air supplied to the fuel cell can be prevented, and the performance degradation of the fuel cell can be prevented. At this time, since it is not necessary to provide a filter or an oil separator in the air supply passage to the fuel cell, an increase in weight and an increase in installation space can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view of a fuel cell air compressor showing a first embodiment of the present invention. This fuel cell air compressor (hereinafter simply referred to as an air compressor) includes a female rotor 5 and a male rotor 7 which are rotating bodies serving as air compression operation units in a compressed air chamber 3 of a casing 1. It is housed in a rotatable manner in a state of being engaged with each other. The female rotor 5 and the male rotor 7 are respectively fixed to a female rotor shaft 9 and a female rotor shaft 11 as connecting shafts, and one end of each rotor shaft 9 and 11 is a bearing 13 provided on the casing 1, and the other end is a casing. 1 is supported by a bearing 15 provided in 1 to be rotatable.

  The ends of the rotor shafts 9 and 11 on the bearing 15 side pass through the partition wall 17 of the casing 1 in which the bearing 15 is set, and are formed on the opposite side of the compressed air chamber 3 with the partition wall 17 interposed therebetween. It protrudes into a certain oil chamber 19. The opening of the casing 1 in the oil chamber 19 is sealed by fixing a lid 21 with a bolt 23.

  A driving timing gear 25 and a driven timing gear 27 that are meshed with each other are fixed to the female rotor shaft 9 and the male rotor shaft 11 in the oil chamber 19, respectively. Among these, the female rotor shaft 9 provided with the driving timing gear 25 is driven through, for example, the lid 21 through the outside, connected to an electric motor (not shown), and the driving force is transmitted via the driven timing gear 27. Transmission to the male rotor shaft 11 causes the male rotor 7 to rotate in synchronization with the female rotor 5.

  Lubricating oil 29 is stored in the oil chamber 19 and lubricates driving mechanism portions such as the driving timing gear 25 and the driven timing gear 27 described above.

  An air suction port 31 is provided at the end of the casing 1 on the opposite side of the lid 21. The rotors 5 and 7 rotate while securing a necessary gap therebetween, thereby sucking air from the air suction port 31 into the suction space 31a of the casing 1 and passing this air through a communication hole (not shown) of the casing 1. Take into the compressed air chamber 3. The air taken into the compressed air chamber 3 is compressed to a predetermined pressure as the volume of the compressed air chamber 3 formed by the rotors 5 and 7 and the casing 1 is gradually reduced with rotation, and the compressed air is compressed. Is discharged from the air discharge port 33 and supplied to a fuel cell (not shown).

  The bearing 15 for rotating and supporting each of the rotor shafts 9 and 11 is disposed so as to be exposed to the oil chamber 19 side of the partition wall 17, and around the rotor shafts 9 and 11 on the compressed air chamber 3 side of the bearing 15. Is provided with an oil seal 35. The portions 9a and 11a of the rotor shafts 9 and 11 provided with the oil seal 35 are smaller in diameter than the portions 9b and 11b provided with the rotors 5 and 7, and further from the portions 9a and 11a provided with an oil seal. The bearing 15 described above is provided in the small diameter portions 9c and 11c.

  By providing the oil seal 35 described above, the lubricating oil in the oil chamber 19 is prevented from flowing into the compressed air chamber 3, and the compressed air is also prevented from flowing out into the oil chamber 19.

  An oil outflow passage 37 is provided in the partition wall 17 corresponding to the portions 9 b and 11 b of the rotor shafts 9 and 11 on the compressed air chamber 3 side with respect to the oil seal 35. As shown in FIG. 2, which is an AA cross-sectional view of FIG. 1, the oil outflow passage 37 includes annular passages 37a and 37b surrounding the rotor shafts 9 and 11, and the annular passages 37a and 37b. The communication passage 37c communicates with the lower passage 37d and extends further downward from the lower annular passage 37b.

  It is assumed that the oil outflow passage 37 is provided in the order of the annular passage 37a, the communication passage 37c, the annular passage 37b, and the lower passage 37d in the direction in which the lubricating oil flows down due to gravity.

  Furthermore, an oil reservoir 39 for collecting lubricating oil flowing down the oil outflow passage 37 is provided at the lower end of the lower passage 37. A drain valve 41 is provided below the oil reservoir 39, and an outlet-side oil reservoir 43 is provided below the drain valve 41.

  The lower part of the outlet side oil reservoir 43 is provided with an open hole 45 that is open to the atmosphere, and a drain plug 47 is detachably attached to the open hole 45.

  The drain valve 41 is assumed to open in conjunction with the start of the air compressor. This valve opening operation is performed based on the flowchart of FIG. 3 described later.

  Next, the operation will be described.

  In the process of operating the air compressor, when the oil seal 35 deteriorates due to wear due to deterioration over time or for some reason, the sealing performance deteriorates, the lubricating oil 29 in the oil chamber 19 is removed from the oil seal portion. It leaks and goes to the compressed air chamber 3, and enters the annular passages 37a and 37b of the oil outflow passage 37 along the way.

  Lubricating oil that has entered the annular passage 37a sequentially falls by gravity through the communication passage 37c, the annular passage 37b, and the lower passage 37d, and the lubricating oil that has entered the annular passage 37b falls by gravity through the lower passage 37d and accumulates oil. It will accumulate in part 39.

  As described above, even when the sealing performance of the oil seal 35 is deteriorated, the oil leaking from the oil seal portion does not flow out to the compressed air chamber 3 but flows through the oil outflow passage 37 to the oil reservoir portion 39, so that the fuel Lubricating oil can be prevented from being mixed into the air supplied to the battery, and the performance of the fuel cell can be prevented from deteriorating. At this time, since it is not necessary to provide a filter or an oil separator in the air supply passage to the fuel cell, an increase in weight and an increase in installation space can be prevented.

  Next, a control operation of a controller (not shown) for the drain valve 41 will be described with reference to the flowchart of FIG. First, the controller (not shown) outputs a rotation command to the air compressor (step S1), and determines whether or not the rotational speed of the air compressor is “0” (step S2). If the rotational speed is “0”, the drain valve 41 is opened for a certain period of time (step S3). That is, the drain valve 41 is opened in conjunction with the start of the air compressor.

  When the drain valve 41 is opened, the lubricating oil accumulated in the oil reservoir 39 falls due to gravity and accumulates in the outlet-side oil reservoir 43. Further, after that, the air compressor is operated at a certain number of revolutions for a certain period of time (step S4), so that the lubricating oil in the oil reservoir 39 is reliably supplied to the outlet-side oil reservoir 43 by the rising pressure of the compressed air chamber 3. Spill into.

  Thereafter, the air compressor is operated at the command rotational speed of the controller (step S5).

  Every time the air compressor is started, the drain valve 41 is opened as described above, and the lubricating oil in the oil reservoir 39 is accumulated in the outlet oil reservoir 43. It can be discharged to the outside by removing the drain plug 47 during regular maintenance or when checking is required.

  Furthermore, the damage state of the oil seal 35 can be predicted by measuring the amount of the released lubricating oil and comparing it with a specified value. If there is no problem with damage to the oil seal 35 at this time, the durability of the air compressor can be maintained by replenishing the oil chamber 19 with lubricating oil from an oil replenishing port (not shown) provided in the casing 1. It becomes possible.

  As mentioned above, according to this invention, there exist the following effects.

  (1) Since oil leaking from the oil chamber toward the compressed air chamber flows out into the oil outflow passage and enters the oil reservoir, it is possible to prevent the lubricating oil from being mixed into the air supplied to the fuel cell. Battery performance degradation can be prevented. At this time, since it is not necessary to provide a filter or an oil separator in the air supply passage to the fuel cell, an increase in weight and an increase in installation space can be prevented.

  (2) When the lubricating oil in the oil chamber that lubricates the gear mechanism leaks toward the compressed air chamber that houses the rotating body, the leaked lubricating oil flows into the oil outflow passage. Mixing into the air can be prevented.

  (3) Since the drain valve provided between the lower part of the oil reservoir and the atmosphere opening side is opened in conjunction with the start of the air compressor, the leaked lubricating oil accumulated in the oil reservoir Can be easily released.

  (4) By removing the drain plug, the lubricating oil accumulated in the oil reservoir can be easily discharged to the outside. Further, by measuring the amount of oil released and replenishing the oil chamber with the measured amount of lubricating oil, it is possible to maintain the durability of the air compressor. Further, by measuring the amount of lubricating oil leakage within a certain period, it becomes possible to grasp the wear state and breakage state of the oil seal portion.

  FIG. 4 is a cross-sectional view of a fuel cell air compressor showing a second embodiment of the present invention. In this embodiment, an oil reservoir 49 is provided further below the lower passage 37d in the oil outflow passage 37, a drain passage 51 communicating with the atmosphere is connected to the lower portion of the oil reservoir 49, and lubricating oil is supplied to the drain passage 51. A filter 53 to be captured and a drain valve 41 used in the first embodiment are provided.

  Here, the drain passage 51 constitutes an oil outflow passage.

  Further, a differential pressure gauge 55 is provided as a differential pressure detecting means for detecting a pressure difference before and after the oil flow direction of the filter 53 in the drain passage 51. Other configurations are the same as those of the first embodiment shown in FIG. The differential pressure gauge 55 and the filter 53 constitute oil amount detecting means.

  In the second embodiment, when the air compressor is started, the drain valve 41 is opened in the same manner as in the first embodiment. Here, the lubricating oil accumulated in the oil reservoir 49 is pumped downstream by the air compressed by the air compressor, and the filtered lubricating oil is captured by the filter 53.

  Further, the pressure difference before and after the filter 53, that is, the pressure loss is measured by the differential pressure gauge 55, and the leaked amount of lubricating oil is grasped from the preset relationship between the differential pressure and the amount of oil captured by the filter 53. Then, the leakage amount is compared with a determination reference value, and if the leakage amount exceeds the determination reference value, measures such as stopping the operation of the air compressor or issuing a warning are taken.

  Thus, according to the above-described second embodiment, the amount of lubricating oil leaked is detected, and the operation is stopped or a warning is issued by comparing the amount with the criterion value. Thus, the failure of the air compressor can be prevented in advance.

  In addition, the amount of lubricating oil that leaks out can be measured easily and reliably every time the air compressor is started, so it is possible to reliably detect air compressor failures at start-up, and when measuring the oil amount, Since the lubricating oil is captured by the filter, the oil can be prevented from flowing out to the atmosphere.

It is sectional drawing of the air compressor for fuel cells which shows 1st Embodiment of this invention. It is AA sectional drawing of FIG. It is a flowchart which shows the valve opening operation | movement of the drain valve in the air compressor for fuel cells of 1st Embodiment. It is sectional drawing of the air compressor for fuel cells which shows 2nd Embodiment of this invention.

Explanation of symbols

3 Compressed air chamber 5 Female rotor (rotary body, air compression operating part)
7 Male rotor (rotary body, air compression operating part)
9 Female rotor shaft (connection shaft)
11 Male rotor shaft (connection shaft)
17 Partition 19 Oil chamber 25 Timing gear for driving (drive mechanism)
27 Driven timing gear (drive mechanism)
29 Lubricating oil 37 Oil outflow passage 39, 49 Oil reservoir 41 Drain valve 45 Open hole opened to the atmosphere 47 Drain plug 51 Drain passage (oil outflow passage)
53 Filter (Oil level detection means)
55 Differential pressure gauge (Differential pressure detection means, Oil amount detection means)

Claims (6)

  In a fuel cell air compressor that feeds air to a fuel cell that generates power upon receiving fuel and air supply, an oil chamber that contains lubricating oil for lubricating the drive mechanism is operated by the drive mechanism Lubricating oil leaked from the oil chamber around a connecting portion between the drive mechanism portion and the air compression operation portion corresponding to the partition wall. An oil outflow passage through which oil flows out is provided, and an oil reservoir for storing the outflowing lubricating oil is provided at the lower end of the oil outflow passage.   The drive mechanism portion is a gear mechanism, the air compression portion is a rotating body that is connected to the gear mechanism via a connecting shaft and rotates, and the oil outflow is inserted into the partition wall through the connecting shaft. 2. The fuel cell air compressor according to claim 1, further comprising a passage.   3. The fuel cell according to claim 1, wherein a drain valve is provided between the lower part of the oil reservoir and the atmosphere opening side, and the drain valve is opened in conjunction with the start of the air compressor. Air compressor.   The fuel cell air according to any one of claims 1 to 3, wherein an opening for opening to the atmosphere is provided in a lower portion of the oil reservoir, and a drain plug is detachably provided in the opening. Compressor.   The oil outflow passage is provided with an oil amount detecting means for detecting the amount of lubricating oil that has flowed out, and the operation of the air compressor is stopped when the amount of lubricating oil detected by the oil amount detecting means exceeds a set value. The fuel cell air compressor according to any one of claims 1 to 4, wherein a warning is generated.   As the oil amount detecting means, there are provided a filter that captures lubricating oil on the oil outflow passage and a differential pressure detecting means that detects a pressure difference before and after the oil flow direction of the filter, and this differential pressure detecting means detects 6. The air compressor for a fuel cell according to claim 5, wherein the amount of lubricating oil captured by the filter is detected based on a pressure difference before and after the filter.

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