KR101211479B1 - Geared motor for refrigerator - Google Patents

Abstract

[PROBLEMS] To obtain a gear motor for a freezer, which can be operated in a freezer without performing warm operation, and has a low cost and a long service life.
[Solution] In the gear motor 10 incorporating a motor used in a freezer and a reducer, an oil seal for sealing the rotating shaft of the reducer, when the target freezing temperature is -T ° C (for example, -30 ° C), The cryogenic oil seal 30, which is guaranteed for use at (T + 10) 占 폚 (i.e., -40 占 폚 if the target freezing temperature is -30 占 폚), is mounted in the reducer 14. The gear motor 10 is intermittently operated so that the temperature in the vicinity of the cryogenic oil seal 30 does not exceed 0 ° C.

Description

Gear motor for refrigerator

This application claims priority based on Japanese Patent Application No. 2009-286880, filed December 17, 2009. All content of that application is incorporated by reference in this specification.

The present invention relates to a freezer gear motor for use in a freezer.

Since the inside of the freezer for storing fresh food and the like is set at a cryogenic temperature, a storage shelf or a carrier table which is installed to be movable in the inside of the freezer can provide a good operation of the gear motor as the driving source. You need to secure it. Here, the "gear motor" in the present invention includes both a motor and a gear reducer directly integrated from the design stage, and a post-integrated one using a coupling or the like.

In patent document 1, the thermostat which accommodated a gear motor in the thermostat box with a heating means is provided. In this thermostat, the heating means is operated when the temperature in the thermobox falls to a predetermined control temperature.

Japanese Unexamined Patent Publication No. 2005-300085

However, the technique with the above-mentioned thermostat requires a heat box or 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, the thermostat is always operated so that the gear motor can be used immediately at any time. Of course, when it is clear that the gearmotor is not used for a long time, it is also possible to turn off the power supply of the thermostat each time. In this case, however, in the use of the gear motor, the operation itself can be started if the gear motor is warmed by the heating means by the heating means, and it is not waited until the grease or the like can function properly. none.

Therefore, it is conceivable to design a gearmotor that can be used as it is in a freezer by using a lubricant and an oil seal (for example, acrylic rubber, hydrogenated nitrile rubber, etc.) developed to be used at a lower temperature. In practice, however, when a gearmotor using a lubricant and oil seal developed as being able to be used at a low temperature, which is the target temperature of the freezer, was operated in the freezer (although the operation itself could be performed without any problem), the oil seal was rarely used. The problem that the lubricant may leak was confirmed.

However, even if the manufacturer brought back the gearmotor in which this problem occurred and verified the oil seal in detail, there was a case that no abnormality was found in the oil seal itself, and the cause was not necessarily clear.

The present invention has been made based on the discovery knowledge obtained by closely examining the cause of oil leakage in such a situation, and the operation of the gear motor in the freezer as it is is provided without installing a thermostat or heating means. In addition to making it possible, it is a problem to prevent the leakage of lubricant and to maintain the life of the oil seal for a long time.

The present invention relates to a gear motor incorporating a motor and a reducer that operate in a freezer, wherein the oil seal for sealing the rotary shaft of the reducer includes a cryogenic oil seal that can be sealed to a temperature at least 10 ° C. or lower than a target freezing temperature. By setting it as the structure to attach, the said subject was solved.

The present invention, as a result of closely examining the characteristics of the oil seal of the gear motor to be used in the freezer, in order to use the gear motor in the freezer without a thermostat or warming operation, the rotary shaft (input shaft or output shaft) of the reduction gear As the oil seal to seal, the cryogenic oil seal which has a sealing performance lower than-(T + 10) ° C on purpose is used when the target freezing temperature is, for example, -T ° C. In short, for example, if the target refrigeration temperature is -30 ° C, a cryogenic oil seal is used which is guaranteed to be used at -40 ° C or lower.

As a result, the gear motor can be used directly in the freezer, and oil leakage can be prevented. The specific reason regarding this oil leakage prevention is demonstrated in detail later.

However, the present invention is a gear motor incorporating a motor and a reducer used in a freezer, comprising an oil seal for sealing a rotation shaft of the reducer, wherein the oil seal can be sealed to a temperature at least 10 ° C. or lower than a target freezing temperature. The gear motor can also be regarded as a freezer gear motor characterized by being intermittently operated so that the cryogenic oil seal becomes a cryogenic oil seal and the temperature around the cryogenic oil seal does not exceed 0 ° C.

In addition, the present invention is a gear motor incorporating a motor and a reducer used in a freezer, comprising an oil seal for sealing a rotation shaft of the reducer, wherein the oil seal can be sealed to a temperature at least 10 ° C. or lower than a target freezing temperature. The gearmotor for the freezer gear motor is operated intermittently so that the cryogenic oil seal becomes a cryogenic oil seal and the temperature around the cryogenic oil seal does not exceed a predetermined time set shorter than the time expected to exceed 0 ° C. You can also figure out.

According to the present invention, it is possible to operate the gear motor in the freezer as it is, and it is possible to effectively prevent the leakage of lubricant.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows an example of the gear motor for freezers to which the operation method which concerns on embodiment of this invention is applied.
2 is an enlarged cross-sectional view of an oil seal on the input side of the freezer gear motor.
3 is a graph of an example of a temperature test around an oil seal and an enlarged view thereof.
4 is a flowchart showing an example of operation control of the gear motor.
5 is a flowchart showing an example of another operation control of the gear motor.

EMBODIMENT OF THE INVENTION Hereinafter, based on drawing, the example of embodiment of this invention is described in detail.

First, the solution principle of the present invention will be described in detail before entering the description of the specific embodiment example.

For example, acrylic rubber is widely known as a material excellent in low temperature sealing performance. Since the material also shows that the material can be used in the catalog value up to -25 ° C, the inventor originally adopted the oil seal related to this material as an oil seal of the gear motor for a freezer in a freezer having a target freezing temperature of -25 ° C. . In reality, however, lubricant leakage sometimes occurred.

As a result of close examination, when it was intended to function in the freezer, it was assumed that rigidity remained in the initial stage of operation, and therefore it was not well followed by subtle shaking or vibration of the shaft. This is inversely guessed from the fact that no abnormality was recognized even when the oil motor was inspected at room temperature by returning with the gear motor. In the initial stage of operation, it is considered that the elasticity is deficient and the urgency is reduced. This point can be said to be a unique situation of a freezer gear motor different from a simple O-ring and the like, and it is considered to be a problem particularly in oil seals of rotary shafts such as input shafts rotating at high speed.

For this reason, the cryogenic oil seal having more excellent low temperature characteristics, that is, the cryogenic oil seal having excellent low temperature sealing performance that can be applied even under-(T + 10) ℃ when the target freezing temperature is -T ℃ (specifically, Was tested, for example, nitrile rubber), and a good result was obtained, supporting that the conjecture was correct.

The present invention has been made based on this discovery knowledge.

However, even when such a further cryogenic oil seal was used as an oil seal of a freezer gear motor, lubricant leakage could be newly confirmed by long-term use.

In the search for countermeasures, it was speculated that the effect of temperature rise was one of the causes. 3 shows an example in which the temperature rise around the oil seal is measured when the motor's rotational speed (rotational speed of the input shaft of the reducer) is 1800 rpm in the freezer where the temperature in the freezer (target freezing temperature) is -25 ° C. Indicates. As can be seen from this experimental example, when the temperature in the freezer is -25 ° C, the temperature around the oil seal is about 10 minutes after the start of operation, which is larger than that at room temperature (about 1.3 times the actual measurement result). It can be confirmed that it rises to near 0 degreeC at once, exceeds 0 degreeC in 10 minutes, and after that, a rise becomes moderate and it becomes almost constant when 40 minutes or more pass.

This result shows that the oil seal periphery has moved up and down the boundary of 0 degreeC when it stops after continuous operation for 10 minutes or more from the start of operation. It is thought that the rise and fall of the temperature around 0 ° C. due to this operation and shutdown cause a problem of condensation.

However, especially when the gear motor is newly introduced or when it is being maintained, such as when brought into the freezer from the outside of the freezer after the test operation at room temperature, the storage shelf or carrier once comes out of the freezer door and then again. In the case of a freezer having an opening structure, it is considered that outside air (air containing moisture) is likely to enter the freezer together with the gear motor, and as a result, condensation around the oil seal results in solidification and melting.

Therefore, the gearmotor concerning this invention is equipped with the cryogenic oil seal which guarantees use at least at-(T + 10) degreeC, when the target refrigeration temperature is -T degreeC from this viewpoint. Preferably, the gear motor is operated intermittently so that the temperature around the oil seal does not exceed 0 ° C. Or it is set as the gearmotor which intermittently operates so that the temperature around the cryogenic oil seal may not exceed predetermined time set shorter than the time estimated to exceed 0 degreeC. As a result, the "phase change" of the water around the cryogenic oil seal is eliminated, and condensation, solidification, and melting are prevented from repeating, and the use environment of the gear motor is very stable.

However, it is also effective to manage to keep the freezer humidity low or to implement measures such that condensation is not a problem on the oil seal.

Hereinafter, the example of a more specific embodiment is demonstrated using FIG. 1, FIG.

1 is a cross-sectional view of a freezer gear motor according to an example of the embodiment of the present invention. Here, the target freezing temperature of the freezer (not shown) is -25 ° C in this example.

This freezer gear motor 10 integrates the motor 12 and the reduction gear 14. In the case of a "gear motor", generally, the motor 12 and the speed reducer 14 are integrated (from the design stage) as in this embodiment. For example, an independently designed motor and a reducer may be integrated through a coupling or connecting bolt. The present invention can be similarly applied when there is a situation in which oil does not want to leak out of the reducer (for example, in the coupling).

The reducer 14 is fitted with an input shaft (rotary shaft) 16 that is also a motor shaft of the motor 12, a hypoid pinion 18 integrally formed on the input shaft 16, and a hypoid pinion 18. The physics has a hypoid gear 20. The hypoid gear 20 is attached to the intermediate shaft 22, and the intermediate pinion 24 formed integrally with the intermediate shaft 22 is engaged with the output gear 26. Then, the rotation of the output gear 26 is output to the outside as the rotation of the hollow output shaft (rotation shaft) 27.

The freezer gear motor 10 includes an oil seal that seals the input shaft 16 and the output shaft 27 of the reducer 14. The oil seal is a cryogenic oil seal 30 which can be sealed to a temperature at least 10 ° C. or lower than the target freezing temperature, and the gear motor 10 so that the temperature around the cryogenic oil seal 30 does not exceed 0 ° C. Is intermittently driven.

More specifically, the input side of the speed reducer 14 includes the cryogenic oil seal 30 (according to the embodiment of the present invention) disposed adjacent to the bearing 28 of the input shaft 16, and the cryogenic oil seal 30 thereof. It is sealed by the oil seal 32 for room temperature (for dust removal) mounted in parallel with the reducer inside. In addition, the output side of the speed reducer 14 is sealed by the cryogenic oil seal 36 (which concerns on embodiment of this invention) arrange | positioned adjacent to the bearing 34 of the output shaft 27. As shown in FIG. The cryogenic oil seal 36 on the output side is different in diameter but structurally similar to the cryogenic oil seal 30 on the input side. Therefore, it demonstrates focusing on the cryogenic oil seal 30 of an input side for convenience.

The cryogenic oil seal 30 is made of nitrile rubber. The nitrile rubber has a low temperature sealing property that can be sufficiently sealed to a target freezing temperature of -25 ° C (to be sufficiently sealed up to -40 ° C (less than or equal to 10 ° C lower than the target freezing temperature of -25 ° C). In addition, since it is resistant to mineral oil-based oils and has abrasion resistance, it is also suitable for use as a freezer gear motor. In fact, even if this nitrile rubber starts direct operation | movement without a warm-up operation in a freezer, the problem of initial stiffness does not arise. However, in addition to nitrile rubber, silicone rubber, ethylene propylene rubber, styrene butadiene rubber, ethylene tetrafluoride resin, fabric and the like also have good low temperature properties as the material of the cryogenic oil seal of the present invention. Among these, silicone rubber is preferable because it is relatively heat resistant, and can effectively cope with the fact that it may be operated outside the freezer.

As enlarged in FIG. 2, the cryogenic oil seal 30 is a simple structure which mainly has the main lip 30A (although the material itself is expensive), and the cost is reduced. On the other hand, in the case of the gear motor 10 which operates in a freezer, it is confirmed that the problem of dust, such as abrasion powder, tends to generate | occur | produce (especially the test | inspection at normal temperature at the time of introduction or maintenance of the gear motor 10). If driving, the tendency is strong). The occurrence of this dust is more likely to be reduced by the operation (maintaining less than 0 ° C) according to the present embodiment, but in this embodiment, the inner side of the reduction mechanism of the cryogenic oil seal 30 is further reduced. Since the oil seal 32 for room temperature for dust removal is mounted in parallel, the dust removal function is strengthened more.

The oil seal 32 for normal temperature is literally used at normal temperature, and the dust lip 32B is provided in addition to the main lip 32A. The oil seal 32 for normal temperature functions as a so-called oil seal when the normal temperature test operation at the time of introduction (which is inevitable in this type of freezer gear motor) or the normal temperature test operation at the time of maintenance is performed outside the freezer. Together, the cryogenic oil seal 30 is reliably protected from dust such as abrasion powder. On the other hand, at the time of normal cryogenic operation in a freezer, most of the dust is captured here, but the hardness increases, and the function as an oil seal is reduced. However, since slide loss hardly increases by that amount, although two oil seals are provided in parallel, it is equipped with the favorable characteristic that operating efficiency can be maintained high and heat generation amount is small (especially in this embodiment).

The freezer gear motor 10 is intermittently operated so that the temperature around the cryogenic oil seal 30 does not exceed 0 ° C. Although this specific operation control is not specifically limited, In this embodiment, the temperature sensor 40 which consists of a thermocouple is attached in the vicinity of the cryogenic oil seal 30, and it detects the temperature around the cryogenic oil seal 30. It is possible.

However, in this embodiment, the temperature sensor is not attached to the cryogenic oil seal 36 on the output side, and cost reduction is aimed at. This is interpreted that the temperature of the cryogenic oil seal 36 on the output side is always lower than the temperature of the cryogenic oil seal 30 on the input side (since the rotation speed of the output shaft 27 is slow). This is because monitoring is enough.

The following is an example of operation control. The operation of the freezer gear motor 10 is performed in accordance with a flowchart as shown in FIG. 4, for example.

When the power supply of the gear motor 10 is turned on in step S2, the temperature around the cryogenic oil seal 30 is detected by the temperature sensor 40 by the thermocouple in step S4. In step S6, it is judged whether or not this temperature is higher than -4 degreeC in consideration of some margin from 0 degreeC. When it is judged that it is -4 degrees C or less, since there is no possibility that the condensation which solidified has melt | dissolved, it returns to step S4 and the temperature monitor and operation of the gearmotor 10 continue as it is. However, in step S6, when it is determined that the temperature around the cryogenic oil seal 30 is higher than -4 ° C, the flow proceeds to step S8, where a warning by a lamp or the like not shown is issued, and there is no power cut operation by the operator. Is checked again in step S10 to see if the temperature is higher than -2 ° C. If it is determined that the temperature around the cryogenic oil seal 30 is -2 ° C or lower, once again after the temperature monitor of step S4, if it is determined that the temperature is higher than -2 ° C in step S10, the flow proceeds to step S12 to cut off the power. . In the meantime, when the operator manually stops the operation of the gear motor 10, the process proceeds to step S12 at any time, and the gear motor 10 is stopped. The flow starts from.

As a result, when the temperature around the cryogenic oil seal 30 is -2 ° C. or lower, the operation can be continued as it is. However, when it is determined that the temperature around the cryogenic oil seal 30 is higher than −2 ° C., the transition is made at that time. Is stopped. Therefore, each oil seal 30, 32, 36 in the gear motor 10 is surely kept below the freezing point so that condensation that has solidified does not melt (of course, no condensation), and each oil seal 30, 32, 36) can maintain a good sealing performance at all times in a stable environment, and can greatly increase the service life.

However, in this example, in addition to the warning threshold (-4 ° C), the power supply has a threshold value (-2 ° C) that is slightly higher and lower than 0 ° C, but only one threshold value (warning) None), and instead of setting the second threshold value, the timer may be operated. Threshold itself is not limited to said -4 degreeC and -2 degreeC.

However, the control (that is, the operating method according to the present embodiment) may be manually turned off in consideration of the fact that there is a case where it is sometimes urgent to operate even at the expense of some service life.

By the way, the important thing in this invention is that the gear motor 10 is intermittently operated so that the temperature around the cryogenic oil seal 30 may not exceed 0 degreeC, and the temperature sensor 40 is an essential requirement. no. For example, the gear motor 10 may be intermittently operated so that the temperature around the cryogenic oil seal does not exceed a predetermined time set shorter than the time expected to exceed 0 ° C.

5 shows an example of the operation control according to this configuration example.

In this operation control, the oil seals 30, 32, and 36 are protected by indirectly estimating the temperature of the cryogenic oil seal 30 in operation time, instead of directly detecting the temperature near each cryogenic oil seal 30. I'm trying to. Therefore, the temperature sensor 40 of the gear motor 10 is unnecessary when this operation control is performed.

When the power supply is turned ON in step S20, it is determined whether or not the third timer t3, which has been started (reset & count start) in step S32 described later at the time of last power-off, has elapsed for 5 minutes or more (step S22). If more than 5 minutes have elapsed, the flow proceeds directly to step S24 and the power is actually turned on. However, if 5 minutes has not yet elapsed, the process waits until 5 minutes has elapsed and proceeds to step S24. Becomes ON. In step S24, the first timer t1 is started (reset & count start) at the same time as the power is turned on.

Subsequently, at step S26, whether or not the first timer (that is, continuous operation time) t1 has exceeded a predetermined time (for example, 8 minutes at which the temperature around the cryogenic oil seal 30 does not reach 0 ° C.) is exceeded. Judging. From the power supply ON, that is, eight minutes have not elapsed since the gear motor 10 actually started to operate, step S26 is traversed and operation continues as it is.

However, if it is determined that the first timer t1 has exceeded eight minutes, the process proceeds to step S28 where a warning by a lamp or the like not shown is issued, and the second timer t2 is started (reset & count start). If it is determined that 2 minutes have elapsed since the second timer t2 is started in step S30, the power supply is cut off in step S32, and at the same time, the third timer t3 is started (reset & count start). This third timer t3 is used to secure an interval of 5 minutes (restart prohibition period) until the power is actually turned on when the next power on operation is made (step S20). Step S22). By the function of this third timer t3, even when the power supply of the gear motor 10 is turned on immediately after continuous operation, it is surely prevented from reaching 0 ° C or more as a result.

However, this restart operation prohibition period (5 minutes in this example) may be appropriately changed depending on the heat dissipation characteristics around the oil seal of the gear motor 10, the ambient temperature (target freezing temperature) and the like. Further, it is better if the variable setting is performed depending on the time of continuous operation immediately before. Naturally, when the immediately preceding continuous operation time is short, the restart operation prohibition period may be short. Thereby, operation below 0 degreeC can be performed more reliably, reducing the frequency of interruption | blocking.

In this embodiment, the threshold value of the first timer t1 is set to 8 minutes, and the threshold value of the second timer t2 is set to 2 minutes, while the continuous operation time is 10 minutes or less according to the experiment described above. This is because it is assumed that the oil seals 30, 32, and 36 in the freezer do not become 0 ° C, and therefore, there is no fear that the condensation that has solidified will melt. The threshold value of the first timer t1 is appropriately set depending on the target temperature of the actual freezer or the amount of heat generated around the oil seal of the gear motor. Incidentally, in most cases other than the freezer according to this embodiment, the temperature is usually not more than 0 ° C within 10 minutes.

Although the present invention has already explained that it is not necessary to physically measure the temperature, it is not necessary to adopt a configuration in which the gear motor power is automatically turned off after actually measuring the continuous operation time by a timer. . That is, for example, the operator consciously considers the continuous operation time and the re-operation prohibition period so that the continuous operation time does not exceed 10 minutes (even when there is no timer means or the like) and then intermittently controls the gear motor. You may do it. Even with such a configuration, it is possible to effectively prevent oil leakage and to significantly increase the service life of the oil seal, thereby obtaining a freezer gear motor that can be used directly in a freezer while minimizing cost increase.

10... Freezer Gear Motor
12... motor
14 ... reducer
30, 36... Cryogenic Oil Seal
32 ... Room temperature oil seal
40 ... temperature Senser

Claims (5)

delete As a gear motor integrating a motor and a reducer used in a freezer,
An oil seal for sealing the rotation shaft of the reducer,
The oil seal is a cryogenic oil seal that can be sealed to a temperature at least 10 ° C. or lower than the target refrigeration temperature.
The gear motor is intermittently operated so that the temperature around the cryogenic oil seal does not exceed 0 ° C.
Gear motor for freezer, characterized in that. As a gear motor integrating a motor and a reducer used in a freezer,
An oil seal for sealing the rotation shaft of the reducer,
The oil seal is a cryogenic oil seal that can be sealed to a temperature at least 10 ° C. or lower than the target refrigeration temperature.
The gear motor is intermittently operated so that the temperature around the cryogenic oil seal does not exceed a predetermined time set shorter than the time expected to exceed 0 ° C.
Gear motor for freezer, characterized in that. The method according to claim 3,
The predetermined time is set to 10 minutes or less
Gear motor for freezer, characterized in that. The method according to any one of claims 2 to 4,
The cryogenic oil seal is selected from nitrile rubber, silicone rubber, ethylene propylene rubber, styrene butadiene rubber, tetrafluoroethylene resin, and fabric
Gear motor for freezer, characterized in that.

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