JP5363299B2 - Gear motor for freezer - Google Patents

Description

  The present invention relates to a gear motor used in a freezer.

  Since the inside of the freezer for storing fresh food and the like is set at an extremely low temperature, the storage shelf and the carriage that are movably installed inside the freezer have some form of good operation of the gear motor as a driving source. It is necessary to secure in. The “gear motor” in the present invention includes both those in which the motor and the speed reducer are directly integrated from the design stage, and those in which the motor and the reduction gear are integrated afterwards using a coupling or the like.

  In patent document 1, the heat retention apparatus which accommodated the gear motor in the heat retention box with a heating means is provided. In this heat retaining device, the heating means is operated when the temperature in the heat retaining box is lowered to a predetermined control temperature.

JP 2005-300085 A

  However, the method including the above-described heat retaining device requires a heat retaining box and a heating control device in addition to the gear motor. In addition, when the gear motor is not used for a long period of time, a large amount of wasted electric power is required in order to keep the heat retaining device constantly operated so that the gear motor can be used immediately at any time. Of course, when it is clear that the gear motor will not be used for a long period of time, it is possible to turn off the power of the heat retaining device each time. However, in this case, when using the gear motor, the gear motor is heated by the heating means via the heat retaining device, and the operation itself cannot be started until the grease or the like can function well. There was also a problem.

  Therefore, it is conceivable to design a gear motor that can be used as it is in a freezer by using a lubricant and an oil seal that have been developed so that they can be used even at lower temperatures. However, when the oil seal with excellent low-temperature seal performance is used and the gear motor is used directly in the freezer without heating, keeping warm or warming up, the oil seal part is rarely used. It was confirmed that there was a problem that the lubricant could leak from

  The present invention was made based on the knowledge obtained by examining the cause of the oil leakage in such a situation, and without installing a heat retaining device, a heating means, etc. It is an object to obtain a gear motor for a freezer that can be operated as it is, has high operating efficiency, and can extend the service life at low cost.

  The present invention relates to a gear motor for a freezer operating in a freezer, which is a gear motor in which a motor and a reducer are integrated, and a first oil seal having a temperature characteristic capable of sealing the rotating shaft of the reducer in the freezer. And at least two types of oil seals including a second oil seal that is incorporated inside the speed reducer of the first oil seal and has a temperature characteristic with a lower temperature side temperature higher than that of the first oil seal. The above-mentioned problems are solved.

  When the present inventor scrutinized the cause of the oil leakage in the gear motor for the freezer, one of the possible causes is a decrease in the durability of the oil seal due to the abrasion powder (dust) of the gears in the reduction gear. It was confirmed. As a countermeasure, in the present invention, the first oil seal having a temperature characteristic capable of sealing the rotating shaft of the reduction gear in the freezer has a temperature characteristic that the lower temperature limit temperature is higher than that of the first oil seal. A second oil seal is provided on the inside of the speed reducer.

  This is because, as a result of further investigation of the cause, in the case of the gear motor for the freezer, it has been confirmed that there is a high possibility that the main cause of the generation of the wear powder is “test operation at normal temperature”. In this type of gear motor for a freezer, it is often necessary to perform a test operation outside the freezer (that is, at room temperature) during introduction or maintenance. Even if it is not normal temperature, a test run may be performed in a state where the temperature is not lowered to the original freezing temperature in the freezer. If the cause is a large amount of abrasion powder (dust) generated in this process, it is better to install it as a dust remover than an oil seal that has good characteristics at extremely low temperatures (the target freezing temperature of the freezer). An oil seal having a temperature characteristic with a lower temperature limit temperature higher than that of the first oil seal is more suitable.

  That is, by providing an oil seal that can be used in a higher temperature environment than the first oil seal, the first oil seal basically serves as a seal function during operation at a cryogenic temperature in the freezer. After securing the second oil seal, even when a test operation or the like is performed outside the freezer, for example, the original good sealing performance (including dust removal) can be exhibited. Become. Moreover, an oil seal whose low temperature side limit temperature is not extremely low is generally low in cost. Furthermore, since the second oil seal has a characteristic that the low temperature side limit temperature is higher than that of the first oil seal, the first oil seal is hardened during operation (under a cryogenic condition in the freezer) and the tension force is increased. It tends to be lower than the seal. For this reason, during operation in the freezer, only the tension force of the first oil seal is effectively applied to the shaft, and energy loss due to the tension and sliding is reduced (due to the presence of the second oil seal itself). There is also a very beneficial advantage of being able to maintain high operating efficiency while capturing much of the dust.

In this sense, when viewed from the viewpoint of “tightening force”, the present invention is “a gear motor in which a motor and a speed reducer are integrated, and the gear motor for a freezer that operates in a freezer. A first oil seal having a tension force characteristic capable of sealing the rotation shaft of the speed reducer, and a tension force characteristic that is incorporated inside the speed reducer of the first oil seal and smaller than the first oil seal in the freezer A gear motor for a freezer comprising at least two types of oil seals with a second oil seal, wherein a lower limit temperature of the second oil seal is higher than a target freezing temperature of the freezer; It can also be captured.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to drive | operate as it is in a freezer, the gear motor for freezers which can drive | operate as it is at high cost at a low operating cost can be obtained.

Sectional drawing which shows an example of the gear motor for freezers to which the operating method which concerns on embodiment of this invention is applied. Expanded sectional view of the oil seal on the input side of the gear motor for the freezer

  Hereinafter, an example of an embodiment of the present invention will be described in detail based on the drawings.

  FIG. 1 is a cross-sectional view of a gear motor for a freezer according to an example of an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the oil seal portion. Note that the target freezing temperature of the freezer (not shown) is −25 ° C. in this example.

  The gear motor 10 for a freezer is obtained by integrating a motor 12 and a speed reducer 14 by fastening a motor casing 12 </ b> A and a speed reducer casing 14 </ b> A with bolts 11. In general, when referring to a “gear motor”, the motor 12 and the speed reducer 14 are generally integrated (from the design stage) as in this embodiment, but the gear motor according to the present invention is often referred to. For example, an independently designed motor and a reduction gear may be integrated through a coupling or a connecting bolt. The present invention can be similarly applied when there is a situation where it is not desired to leak oil outside the reduction gear (for example, in the coupling).

  The speed reducer 14 includes an input shaft (rotary shaft) 16 that also serves as a motor shaft of the motor 12, a hypoid pinion 18 that is integrally formed with the input shaft 16, and a hypoid gear 20 that meshes with the hypoid pinion 18. The hypoid gear 20 is incorporated in the intermediate shaft 22, and an intermediate pinion 24 integrally formed with the intermediate shaft 22 meshes with the output gear 26. Then, the rotation of the output gear 26 is output to the outside as the rotation of the output shaft 27.

  In the gear motor 10 according to this embodiment, the input shaft 16 of the speed reducer 14 includes a cryogenic oil seal (first oil seal) 30 made of silicone rubber and a room temperature oil seal (first oil seal) made of acrylic rubber. 2 oil seals) 32 are sealed by two types of oil seals (details will be described later). The output side of the speed reducer 14 is sealed only by a cryogenic oil seal 36 (made of the same material as the input side) disposed adjacent to the bearing 34 of the output shaft 27. That is, in this example, the present invention is not applied to the output side of the speed reducer 14. This is because on the output side, the rotational speed is low, and damage due to wear powder hardly causes a problem, so the cost is reduced. However, it goes without saying that the present invention may be applied to the seal of the output shaft (rotary shaft), and a corresponding improvement in sealing performance and an increase in the oil seal life can be obtained.

  As shown in an enlarged view in FIG. 2, both the cryogenic oil seal 30 and the room temperature oil seal 32 have a simple structure mainly including main lips 30A and 32A (without auxiliary lips), thereby reducing costs. Is planned. However, in the present invention, the specific structure of the first and second oil seals is not limited to this example. For example, a structure having an auxiliary lip is more effective in terms of dust removal.

  The input-side cryogenic oil seal 30 is disposed adjacent to the bearing 28 of the input shaft 16, and in this embodiment, is formed of silicone rubber as described above. The silicone rubber has a temperature characteristic that can seal the speed reducer at the target refrigeration temperature of the freezer (has a tension characteristic that can seal the speed reducer at the target refrigeration temperature of the freezer). Here, the reason for dare to refer to “for cryogenic use” is as follows. That is, the inventor initially used an acrylic rubber oil seal for the purpose of using the first oil seal of the gear motor for a freezer having a target freezing temperature of −25 ° C. However, the hardness remains in the initial stage of operation, and therefore, there was a rare occurrence of oil leakage that was presumed not to be able to follow subtle vibrations or vibrations of the shaft. For this reason, it is because the silicone rubber for cryogenic temperature which has a better low-temperature sealing performance than acrylic rubber is adopted. This can be said to be a situation unique to a gear motor for a freezer that is different from a simple O-ring or the like. When applied to an oil seal for an input shaft that rotates at a high speed, as in this embodiment, for example, when the target refrigeration temperature is -T ° C, use at least at-(T + 10) ° C is guaranteed. It is desirable to employ a cryogenic oil seal. Silicone rubber has a low-temperature sealing characteristic (tight force characteristic) that is more than sufficient for the target refrigeration temperature of -25 ° C. Even if the direct operation is started without warm-up operation, problems such as initial hardness etc. Does not occur.

  Even if the main material is the same, the low temperature side limit temperature (low temperature seal characteristics) of the oil seal differs slightly (sometimes greatly) depending on the structure of the oil seal, the shape of the lip, the type and amount of additives, and the like. For this reason, the actual situation is that each company sets or designates an allowable temperature for a specific material unique to the company. From this point of view, as long as each company's catalog is viewed, nitrile rubber, as well as silicone rubber, is resistant to mineral oil and has wear resistance, so it is suitable for use as a gear motor for a freezer. In addition, ethylene propylene rubber, styrene butadiene rubber, tetrafluoroethylene resin, fabric, and the like also have good low temperature characteristics as a material for the cryogenic oil seal of the present invention.

  On the other hand, the oil seal 32 for room temperature uses acrylic rubber in this embodiment as described above. For example, according to the catalog of NOK Co., Ltd., -25 ° C. is the limit temperature on the low temperature side specified in the specifications, but as in this embodiment, the extreme of silicone rubber This is because, when used in combination with the low temperature oil seal 30, rather good characteristics can be obtained (compared to arranging two cryogenic oil seals). In other words, acrylic rubber has a lower temperature limit temperature higher than silicone rubber (the temperature limit temperature on the low temperature side is −60 ° C. according to the catalog), and the gear motor is operated in a temperature environment other than the original freezer. Rather, it is because the compressive force characteristic and sliding characteristic better than silicone rubber are obtained.

  Next, the operation of the gear motor 10 will be described.

  When the gear motor 10 is operated at an extremely low temperature in a normal freezer, the cryogenic oil seal 30 functions effectively, and good sealing performance can be obtained. At this time, the oil seal 32 for room temperature captures most of the dust, but since the hardness is high (because of the extremely low temperature) and the oil seal does not fully perform its original function, there is almost no sliding loss. Even though two oil seals are installed, the operation efficiency can be maintained high and the calorific value can be kept small.

  In addition, the normal temperature oil seal 32 can reliably prevent dust such as wear powder from moving to the cryogenic oil seal 30 side when the gear motor 10 is introduced or during a test operation during maintenance. Further, the cost can be reduced with respect to the configuration in which two cryogenic oil seals 30 are arranged side by side.

  The effect that the normal temperature oil seal 32 can effectively prevent dust from entering and sliding around the sliding surface of the cryogenic oil seal 30 greatly contributes to an increase in the life of the cryogenic oil seal 30. In particular, when the object to be sealed is the rotating shaft of the reduction gear, particularly the input shaft 12 that rotates at a high speed, the effect becomes remarkable.

  In this embodiment, acrylic rubber, which is an oil seal for room temperature, is used as the second oil seal, which effectively eliminates dust and achieves high-efficiency (low-loss) operation, which also reduces costs. However, in the present invention, the second oil seal does not necessarily need to be “for room temperature”, and in short, the lower limit temperature on the lower temperature side than the main oil seal for cryogenic temperature (first oil seal). The type is not particularly limited as long as it has high temperature characteristics or smaller tension characteristics. For example, the first oil seal for cryogenic temperatures is silicone rubber (for example, the low temperature side limit temperature is −60 ° C. according to the catalog of NOK Co., Ltd.), and the second oil seal is nitrile rubber (the same catalog of According to this, the low temperature side limit temperature may be a combination of −40 ° C.).

  Moreover, in the said embodiment, although the 1st and 2nd oil seal was each arrange | positioned 1 each (2 pieces in total), it may be 3 or more, or 3 or more types. Regarding combinations, for example, A) “for cryogenic temperature”, “for sub-low temperature”, “for sub-low temperature” may be used, or B) “for cryogenic temperature”, “for sub-low temperature”, “for room temperature”, and C ) A combination of “for cryogenic temperature”, “for room temperature”, and “for room temperature” may be used. In this example, in order of A) → C), “Evaluation of sealing performance including dust removal during operation in freezer” is more important than “Dust removal during test operation at normal temperature, etc. The effect of changing to “cost” can be obtained. Of these, the combination of B) is particularly preferable in that the target freezing temperature of the user's freezer is unknown (whatever the target freezing temperature) can be flexibly handled. Of course, in any of the examples, the sealing performance is enhanced in both the freezer operation and the test operation as compared with the above two examples.

  Further, as described above, the configuration of the first and second oil seals is not limited to the above example, and may be, for example, a configuration of a plurality of lips provided with auxiliary lips for dust removal in addition to the main lip. .

DESCRIPTION OF SYMBOLS 10 ... Gear motor for freezer 12 ... Motor 14 ... Reduction gear 30 ... Cryogenic oil seal (first oil seal)
32 ... Oil seal for normal temperature (second oil seal)

Claims (6)

In a gear motor for a freezer that operates in a freezer, which is a gear motor in which a motor and a speed reducer are integrated,
A first oil seal having a temperature characteristic capable of sealing the rotating shaft of the speed reducer in the freezer;
It is provided with at least two types of oil seals including a second oil seal that is incorporated inside the speed reducer of the first oil seal and has a lower temperature side limit temperature than the first oil seal. Gear motor for freezer. In a gear motor for a freezer that operates in a freezer, which is a gear motor in which a motor and a speed reducer are integrated,
A first oil seal having a tension force characteristic capable of sealing the rotary shaft portion of the speed reducer in the freezer;
Including at least two types of oil seals, which are incorporated inside the speed reducer of the first oil seal, and a second oil seal having a smaller compression force characteristic than the first oil seal in the freezer ; and
A gear motor for a freezer , wherein a lower temperature limit temperature of the second oil seal is higher than a target freezing temperature of the freezer. In claim 1 or 2,
The gear motor for a freezer, wherein the first oil seal is selected from silicone rubber and nitrile rubber. In claim 1 or 3 ,
The gear motor for a freezer, wherein a lower limit temperature of the second oil seal is higher than a target freezing temperature of the freezer. In claim 2 or 4,
The gear motor for a freezer, wherein the second oil seal is a room temperature oil seal. In any one of Claims 1-4,
The gear motor for a freezer, wherein the second oil seal is selected from acrylic rubber and nitrile rubber.

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