JP2020067151A - Gear device - Google Patents

Abstract

To provide a gear device that enables smooth operation of a gear type power transmission mechanism, prevention of environmental pollution due to leakage of a lubricating liquid, and prevention of fire, and that facilitates disposal of a used lubricating liquid.SOLUTION: A gear type speed reduction device 8 comprises: a housing 10; a parallel gear mechanism having first to eighth gears 15-22 each disposed in the housing 10 and engaged with each other; an input shaft 11 joined to the first gear 15; an output shaft 9 joined to the eighth gear 22; and a lubricating liquid supply device 30 that supplies an aqueous lubricating liquid to the parallel gear mechanism. The aqueous lubricating liquid contains water and sodium polyacrylate. An amount of sodium polyacrylate to water in the aqueous lubricating liquid is 1-5 mass%. A hydrogen index of the aqueous lubricating liquid is pH 7-pH 11 (preferably pH 8-pH 10).SELECTED DRAWING: Figure 2

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear device in which a gear type power transmission mechanism having a plurality of gears arranged in a housing and meshing with each other or sequentially is lubricated with a water-based lubricating liquid.

  For large-scale mechanical equipment driven by a motor, such as a hoisting sluice installed in a river, lake, shore, etc., the rotation of a motor that rotates at high speed must be reduced in order to hoist a heavy door. A gear type speed reducer that generates high torque is provided. This type of gear type speed reducer generally has a structure in which a plurality of gears that mesh with each other or sequentially are arranged in a housing (for example, see Patent Documents 1 to 4).

  In this type of gear type speed reducer, generally, in order to reduce wear due to friction of gears meshing with each other, a lubricating liquid is circulated or sprayed or sprayed on the gears, or the gears are partially dispersed in the lubricating liquid stored in the housing. Or fully immersed. As a lubricating fluid for a gear type speed reducer, a lubricating oil containing mineral oil as a main raw material has been widely used because of its suitable viscosity and high lubricity.

JP, 2005-337393, A JP, 2013-044650, A JP, 2013-100680, A JP, 2018-105017, A

  As described above, the gear type speed reducer that uses the lubricating oil as the lubricating liquid has a problem that if the lubricating oil leaks to the outside, it may flow into public waters such as rivers, lakes, and oceans, causing serious environmental pollution. . Further, since the lubricating oil is a combustible substance, there is a problem that fire may occur in the gear type speed reducer due to misfire, spread of fire, accident or the like. Further, the lubricating oil needs to be replaced with fresh oil regularly or appropriately due to deterioration or the like, but there is a problem that the processing or disposal of waste oil is complicated.

  It is to be noted that these problems are not limited to the gear type speed reducer, and a gear type power transmission mechanism having a plurality of gears arranged in the housing and meshing with each other or sequentially, and supplying a lubricating liquid to the gear type power transmission mechanism. It generally occurs in a gear device including a lubricating liquid supply device.

  The present invention has been made to solve such a problem, can smoothly operate a gear type power transmission mechanism, can prevent environmental pollution due to leakage of lubricating liquid, and can cause a fire. It is an object of the present invention to provide a gear device capable of preventing the above-mentioned problems and easily treating or disposing of a used lubricating liquid.

The gear device according to the present invention made to solve the above problems,
Housing,
A gear type power transmission mechanism having a plurality of gears respectively arranged in the housing and meshing with each other or sequentially;
A first shaft connected to a predetermined gear of the gear type power mechanism and protruding to the outside of the housing;
A second shaft connected to a gear other than the predetermined gear and protruding to the outside of the housing;
A gear device comprising a lubricating liquid supply means for supplying an aqueous lubricating liquid to the gear type power transmission mechanism,
The water-based lubricating liquid contains water and sodium polyacrylate, and the amount of sodium polyacrylate with respect to water in the water-based lubricating liquid is in the range of 1 to 5 mass%,
The hydrogen index of the aqueous lubricant is within the range of pH 7 to pH 11 (preferably pH 8 to pH 10).

  In the gear device according to the present invention, the hydrogen index of the water-based lubricating liquid is preferably adjusted within the range of pH 7 to pH 11 (preferably pH 8 to pH 10) by adding sodium hydroxide or acetic acid.

  In the gear device according to the present invention, the gear type power transmission mechanism may be a parallel type gear mechanism in which shafts supporting a plurality of gears are arranged in parallel. In this case, the first shaft may be an input shaft that inputs power to the parallel gear mechanism, and the second shaft may be an output shaft that outputs power from the parallel gear mechanism.

  In the gear device according to the present invention, the gear type power transmission mechanism may be a planetary gear mechanism. In this case, the first shaft may be an input shaft that inputs power to the planetary gear mechanism, and the second shaft may be an output shaft that outputs power from the planetary gear mechanism.

  In the gear device according to the present invention, the water-based lubricating liquid may contain propylene glycol. In this case, the amount of propylene glycol added to water in the water-based lubricant is propylene whose freezing point is the lower limit temperature of use of the gear device which is preset within a temperature range lower than 0 ° C. and higher than the freezing point of propylene glycol. It is preferably the same as or more than the amount of propylene glycol added to water in the aqueous glycol solution.

  In the gear device according to the present invention, the water-based lubricating liquid may contain ethanol. In this case, the amount of ethanol added to water in the water-based lubricating liquid is in the aqueous ethanol solution whose freezing point is the lower limit temperature of use of the gear device, which is preset within a temperature range lower than 0 ° C. and higher than the freezing point of ethanol. It is preferable that the amount is equal to or more than the amount of ethanol added to water.

  According to the gear device of the present invention, since the water-based lubricating liquid is used as the lubricating liquid of the gear type power transmission mechanism instead of the lubricating oil, even if a leakage of the lubricating liquid occurs in the gear device, the oil of the surrounding water environment etc. No pollution occurs. In addition, since the water-based lubricating liquid is nonflammable, there is no possibility of fire in the gear device, which is extremely advantageous in terms of fire protection. Furthermore, since the used water-based lubricating liquid can be discharged to public water bodies or public sewers, its treatment or disposal is easy.

1 (a) is a schematic side view of a wire rope winch type gate opening / closing device, and FIG. 1 (b) is a gear type speed reducer according to the present invention which constitutes the gate opening / closing device shown in FIG. 1 (a). It is an expanded partial cross-section top view of FIG. FIG. 3 is a schematic side cross-sectional view of a gear type speed reducer and a lubricating liquid supply device that supplies an aqueous lubricating liquid to the gear type speed reducer. It is a graph which shows the relationship of the addition amount of sodium polyacrylate with respect to water, and kinematic viscosity about 40 degreeC sodium polyacrylate aqueous solution. It is a graph which shows the change characteristic with respect to temperature of the kinematic viscosity of sodium polyacrylate aqueous solution and lubricating oil. 5A to 5C are schematic diagrams of a dynamic friction coefficient measuring device for measuring a dynamic friction coefficient between a fixed channel and a movable member that moves in the channel in the longitudinal direction. . Coefficient of dynamic friction between a moving movable object and a fixed channel measured using the dynamic friction coefficient measuring device shown in FIG. 5, and sodium polyacrylate of a water-based lubricating liquid interposed between the movable object and the channel. It is a figure which shows the relationship of addition amount. It is a graph which shows the relationship between the concentration and the freezing point in the ethanol aqueous solution and the propylene glycol aqueous solution.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. In addition, in this embodiment, the present invention will be described with respect to a gear type speed reducer for a wire rope winch type (hoisting type) gate opening / closing device. Alternatively, the present invention can be widely applied to various gear devices in which a gear type power transmission mechanism having a plurality of gears that are sequentially meshed with each other is arranged in a housing and an aqueous lubricant is supplied to the gear type power transmission mechanism. Further, in this embodiment, the gear type power transmission mechanism is a parallel type gear mechanism in which gears are arranged adjacent to each other in parallel, but the gear type power transmission mechanism to which the present invention is applied is not limited to such a type. Instead, it may be a gear mechanism of another type (for example, a planetary gear mechanism). The planetary gear mechanism includes, as an example, a sun gear, an internal gear located outside the sun gear, a planetary gear that meshes with both the sun gear and the internal gear, and a planet carrier that takes out the revolution movement of the planetary gear, One of the sun gear, the internal gear and the planet carrier is fixed, and the other two are connected to the input shaft and the output shaft, respectively.

<Outline of gate opening / closing device and gear type speed reducer>
As shown in FIGS. 1 (a) and 1 (b), a gate opening / closing device S installed in, for example, a river, an agricultural waterway, a lake, a shore, etc. (not shown) includes a door body 2 for opening and closing the sluice 1. While it is raised by power, it is lowered by its own weight. That is, the water gate 1 is opened and closed by the raising and lowering operation of the door body 2. The door body 2 is suspended by a wire rope 3, and the wire rope 3 is wound around a wire drum 4. The wire drum 4 is coaxially attached to the rotating shaft 5 and rotates integrally with the rotating shaft 5. The rotary shaft 5 is rotatably supported by the rotary shaft support portion 6.

  When the rotating shaft 5 and the wire drum 4 are rotationally driven by the electric motor 25 and rotate in a predetermined rotation direction (for example, a clockwise direction when viewed from the rotating shaft support portion side), the wire rope 3 is wound around the wire drum 4, The door body 2 rises. When the door body 2 is lowered by its own weight (gravity), the wire drum 3 rotates the wire drum 4 in a direction opposite to the predetermined rotation direction, and the winding of the wire rope 3 is released. The rotating shaft 5 is on the side opposite to the wire drum 4 with respect to the direction in which the central axis extends, and the output shaft 9 of the gear type speed reducer 8 (hereinafter, abbreviated as "speed reducer 8") is provided by a coupling 7 (coupling). Are coaxially connected to.

  As shown in FIG. 1B, the speed reducer 8 includes a housing 10 and a plurality of gears 15 to 22 that are respectively arranged in the housing 10 and mesh with each other or sequentially. Further, in addition to the output shaft 9, An input shaft 11 and first to third intermediate shafts 12 to 14 arranged between the input shaft 11 and the output shaft 9 are provided. Although not shown in detail, the output shaft 9, the input shaft 11, and the first to third intermediate shafts 12 to 14 are rotatably supported by bearings fixed to the housing 10 of the speed reducer 8. A part of the output shaft 9 and the input shaft 11 is projected to the outside of the housing 10 via a bearing. The first gear 15 is coaxially attached to the input shaft 11. A second gear 16 and a third gear 17 are coaxially attached to the first intermediate shaft 12. A fourth gear 18 and a fifth gear 19 are coaxially attached to the second intermediate shaft 13. A sixth gear 20 and a seventh gear 21 are coaxially attached to the third intermediate shaft 14. The eighth gear 22 is coaxially attached to the output shaft 9. Helical gears are used for the first to eighth gears 15 to 22. Needless to say, a gear other than the helical gear may be used.

  Here, the first gear 15 and the second gear 16 mesh with each other at a predetermined gear ratio (for example, 5) larger than 1, and the third gear 17 and the fourth gear 18 have a predetermined gear ratio larger than 1 (for example, 4). The fifth gear 19 and the sixth gear 20 are meshed with each other at a predetermined gear ratio larger than 1 (for example, 4), and the seventh gear 21 and the eighth gear 22 are meshed with each other at a predetermined gear ratio larger than 1 (for example, 4). Are meshing with each other. That is, the speed reducer 8 increases the torque from the input shaft 11 to the output shaft 9 at a speed ratio of 320. When the door body 2 descends due to its own weight, the gear ratio when torque is transmitted from the output shaft 9 to the input shaft 11 (when the door is reversely driven) is such that the torque is transmitted from the input shaft 11 to the output shaft 9. It is the reciprocal of the gear ratio (when the speed is increased).

  The gate opening / closing device S includes an electric motor 25 that rotationally drives the input shaft 11 when raising the door body 2. An electric motor rotating shaft (not shown) fixed to the rotor of the electric motor 25 is coaxially connected to the input shaft 11 via a connector or a coupling (not shown). Commercial electric power is supplied to the electric motor 25 from a power source (not shown) through the conductor wire 26 and the control panel 27. The input shaft 11 and the electric motor rotating shaft may be mechanically engaged with each other through a pair of gears or the like to transmit power, instead of being connected by a connector or a coupling.

  As shown in FIG. 2, a lubricating liquid supply device 30 is provided to supply the water-based lubricating liquid to the first to eighth gears 15 to 22 of the speed reducer 8. The lubricating liquid supply device 30 is of a type in which an aqueous lubricating liquid is circulated and continuously sprayed or sprayed or flowed down to the first to eighth gears 15 to 22 to be supplied. However, the present invention is not limited to the lubricating liquid supply device 30 of this type, but the water-based lubricating liquid is stored in the housing 10, and the first to eighth gears 15 to 22 are partially included in the water-based lubricating liquid. It may be of a type in which it is totally or entirely immersed.

  The lubricating liquid supply device 30 includes a lubricating liquid supply device 31 arranged in the housing 10 above the first to eighth gears 15 to 22. The lubricating liquid feeder 31 has a plurality of nozzles 32 for injecting, spraying, or flowing down the water-based lubricating liquid to the first to eighth gears 15 to 22. As a result, the first to eighth gears 15 to 22 and their meshing parts are constantly wetted and lubricated by the water-based lubricating liquid supplied from the lubricating liquid supply device 31. Then, in the vicinity of the lower portion or the bottom portion of the housing 10, the water-based lubricating liquid that has flowed down or dropped from the first to eighth gears 15 to 22 is retained.

  The lubricating liquid supply device 30 includes a lubricating liquid storage tank 33 for storing the aqueous lubricating liquid to be supplied to the speed reducer 8 and a lubricating liquid for recirculating the aqueous lubricating liquid retained in the housing 10 to the lubricating liquid storage tank 33. And a return passage 34. One end of the lubricating liquid recirculation passage 34 is connected to the lubricating liquid discharge port 35 provided in the lower portion of the housing 10 or in the vicinity of the bottom portion thereof, and the other end of the lubricating liquid recirculation passage 34 is located above the lubricating liquid storage tank 33. Is connected to the lubricating liquid receiving port 36 provided in the. The water-based lubricating liquid staying in the housing 10 flows down into the lubricating liquid storage tank 33 by gravity.

  Further, the lubricating liquid supply device 30 pressurizes or transports the water-based lubricating liquid stored in the lubricating liquid storage tank 33 to the lubricating liquid supply device 31 arranged in the housing 10, so that an electric motor (not shown) is provided. A pump 37 driven by the pump 37 and a lubricating liquid supply passage 38 for guiding or transporting the water-based lubricating liquid discharged from the discharge port of the pump 37 to the lubricating liquid supplier 31. The pump 37 may be any pump as long as it can discharge the water-based lubricating liquid at an appropriate discharge pressure and discharge amount according to the size of the speed reducer 8 to be lubricated. For example, a radial type or axial type plunger pump (piston pump), a vane pump, a gear pump, a screw pump, or the like can be used.

  Hereinafter, the characteristics and performance of the water-based lubricating liquid that lubricates the first to eighth gears 15 to 22 of the speed reducer 8 will be specifically described. However, such an aqueous lubricating liquid is not limited to the speed reducer 8 according to the present embodiment, but a gear type power transmission mechanism having a plurality of gears meshing with each other or sequentially is arranged in the housing. It is widely used in various gear devices that supply a water-based lubricating liquid to. Therefore, in the following, the characteristics, performance, etc. of the water-based lubricating liquid will be described with reference to a gear device which is a superordinate concept of the reduction gear 8.

  As described above, generally, in the conventional gear device including the gear type power transmission mechanism, the lubricating oil made of mineral oil is used as the lubricating liquid for reducing the frictional resistance of the gear. However, since such lubricating oil is flammable, there is a risk of causing a fire in the gear device due to misfire, spread of fire, accident, or the like. Further, when the gear device is used as, for example, a speed reducer of a gate opening / closing device for opening / closing a floodgate of a river, leakage of lubricating oil during an earthquake or the like may impair the water environment over a wide downstream water area. Furthermore, the disposal or treatment of the lubricating oil after its useful life has been complicated.

  Therefore, the present inventor has no risk of causing a fire as a lubricating liquid that replaces such a lubricating oil, does not impair the water environment even if it leaks into a river, etc., and easily disposes or treats it after its useful life has passed. As a new lubricating liquid, we have developed a water-based lubricating liquid containing water as a main component and containing no harmful substances to the living body. The water-based lubricating liquid thus developed satisfies the following items as much as possible.

<Matters to be filled with water-based lubricant>
(1) The kinematic viscosity is the same as the lubricating oil (2) The temperature change of the kinematic viscosity is small (3) The dynamic friction coefficient between the sliding parts where the lubricating liquid is present is the same as when the lubricating oil is used. (4) No toxicity to living organisms (preferably added to food)
(5) Low environmental pollution due to leakage / discharge (6) No possibility of fire (7) Do not freeze at low temperatures in cold regions (8) Almost no deterioration due to oxidation (9) Aluminum-based materials And low metal corrosiveness to iron-based materials (10) No adverse effects due to the inclusion of water vapor in the air (11) Good bubble separation in the liquid storage tank (12) Biological deterioration (rotting) Almost nothing

The main components of the aqueous lubricant according to the present invention are, for example, as follows.
(1) Water: for example, pure water, purified water, distilled water (2) Thickener and friction reducing agent: for example, sodium polyacrylate, polyacrylic acid (3) Antifreezing agent: for example, propylene glycol, ethanol ( 4) pH adjuster: For example, sodium hydroxide, acetic acid If necessary, the aqueous lubricant is colored with a synthetic dye, a natural dye, preferably an edible dye. This makes it possible to identify products, prevent misuse and accidental ingestion, and quickly detect external leakage.

  The kinematic viscosity of the water-based lubricating liquid is mainly due to its component, sodium polyacrylate (hereinafter referred to as “PANa”). As the sodium polyacrylate, for example, Aron (registered trademark) A-20L manufactured by Toagosei Kagaku Co., Ltd. can be used. Table 1 below shows kinematic viscosities at 40 ° C. of various sodium polyacrylate aqueous solutions (hereinafter referred to as “PANa aqueous solutions”) measured or calculated by the present inventor. For the kinematic viscosity of the PANa aqueous solution, the relative viscosity of the PANa aqueous solution with respect to pure water is measured using an Ostwald viscometer, and the viscosity of the PANa aqueous solution is calculated from this relative viscosity and the viscosity of well-known water (known). It is calculated from the density of the aqueous solution. In addition, Table 1 also shows the kinematic viscosity (standard value) at 40 ° C. of the lubricating oil generally used in this type of gear device.

FIG. 3 is a graph showing the relationship between the amount of PANa added to water and the kinematic viscosity of a 40 ° C. PANa aqueous solution prepared based on the data shown in Table 1. According to the graph shown in FIG. 3, it can be seen that the addition amount of PANa and the kinematic viscosity have a substantially unique functional relationship. Therefore, by using the graph shown in FIG. 3, the amount of PANa added is preferably set to prepare an aqueous lubricant having a kinematic viscosity at 40 ° C. of any value within the range of 0.6 to 250 mm ² / s. be able to.

As described above, the water-based lubricating liquid can have an arbitrary value within the range of approximately 0.6 to 250 mm ² / s at 40 ° C. by adjusting the amount of PANa added. It is possible to make the kinematic viscosity of the same as or similar to the kinematic viscosity of the conventionally used lubricating oil (for example, ISO VG22, VG32, VG46, VG68, VG100, VG150). According to FIG. 3, in order to make the kinematic viscosity of the water-based lubricating liquid the same as that of commonly used lubricating oil (generally 20 to 165 mm ² / s), the amount of PANa added to water is 1 to 5 wt. It is understood that the adjustment should be made within the range of%.

  FIG. 4 is a graph showing change characteristics (dependence) of the kinematic viscosity of a PANa aqueous solution and the kinematic viscosity of a lubricating oil (ISO VG32) with the addition amount of PANa being 0.45 wt% or 1.3 wt% with respect to temperature. As is clear from FIG. 4, the change in the kinematic viscosity of the PANa aqueous solution with respect to temperature is extremely smaller than the change in the kinematic viscosity of the lubricating oil with respect to temperature. Lubricating oil (ISO VG32) has a kinematic viscosity rapidly increasing with a decrease in temperature, particularly in a temperature range of 40 ° C. or lower, so that the kinematic viscosity becomes too high at low temperatures (for example, 0 to 10 ° C.). It may become unusable and may need to be replaced with a less viscous lubricant. On the other hand, since the kinematic viscosity of the water-based lubricating liquid does not become so high even in a low temperature state, it can be used as it is at a low temperature (for example, 0 to 10 ° C.).

  Lubricating liquid used in a gear device equipped with a gear type power transmission mechanism reduces frictional resistance between gears meshing with each other and significantly reduces sliding friction between gears to prevent wear of gears due to friction. Must be one. Generally, if the dynamic friction coefficient (friction force / pressing force) of sliding friction between gears is approximately 0.02 or less when a lubricating liquid is present between the gears, practically no problem occurs in the gear device. Hereinafter, the friction reducing property of the water-based lubricating liquid will be described.

  5 (a) to 5 (c) show sliding friction between a channel fixed on a table and a movable member that moves (slides) in the channel in the longitudinal direction of the channel used by the present inventor. 1 schematically shows a dynamic friction coefficient measuring device for measuring the dynamic friction coefficient of the. This dynamic friction coefficient measuring device includes a table, a carriage traveling on the table, a tension gauge fixed to the carriage, a weight connected to the front portion of the carriage via a thread, and a pulley for guiding the thread, It is equipped with a channel, a movable object that slides in the channel, and a movable object that is connected to the rear part of the tension gauge fixed to the trolley via a nylon line.The tension gauge controls the tension applied to the nylon line. taking measurement.

The specifications of the main components of the dynamic friction coefficient measuring device are as follows, for example.
(1) Channel This is a "U" -shaped channel made of stainless steel whose inner peripheral surface is smooth.
Width 50mm Height 25mm Length 1500mm Thickness 3mm
(2) Movable Object This is a stainless steel “U” -shaped channel that can be housed in the channel and that can slide in the channel longitudinal direction and has a smooth outer peripheral surface.
Width 40mm Height 30mm Length 100mm Wall thickness 1mm Mass 92g
(3) Trolley This is a simple mechanical trolley for experiments, which has aluminum wheels and whose main body is made of plastic, on which a luggage (weight) having a desired mass can be placed.
Length 135mm Width 75mm Height 35mm Weight 98g (without luggage)
(4) Tension gauge A spring-type rod-type tension gauge having a measurement range of 0 to 50 g weight or 0 to 10 g weight, which is fixed to the carriage so as to extend in the front-rear direction and measures the tension applied to the nylon line. It is like this.

Then, using the dynamic friction coefficient measuring device shown in FIGS. 5A to 5C, the friction reducing characteristics of the water-based lubricating liquid and the lubricating oil were evaluated by the following procedure.
(1) The movable member is arranged in the channel after closing both longitudinal ends of the channel.
(2) A lubricating liquid whose friction reduction characteristic is to be evaluated is injected into the channel, and the movable member and the channel are brought into sliding contact with each other via the lubricating liquid.
(3) After adjusting the mass of the weight and the mass of the load loaded on the trolley, the weight is dropped by gravity to move the trolley in the channel longitudinal direction at a predetermined constant speed to move the movable member in the channel longitudinal direction. Slide it on.
(4) When the moving speed of the movable member is constant, the tension applied to the nylon line by the tension gauge, that is, the forward force applied to the movable object is measured.
(5) The forward friction force applied to the movable object is divided by the gravity (92 g weight) applied to the movable object to calculate the dynamic friction coefficient between the movable object and the channel when the lubricating liquid is present.
(6) The friction reduction characteristics of the lubricating liquid are evaluated based on the magnitude of the dynamic friction coefficient between the movable object and the channel when the lubricating liquid is present. The dynamic friction coefficient between the movable object and the channel is almost the same as the dynamic friction coefficient of sliding friction between the gears of the gear device.

  The moving speed of the carriage can be made constant by adjusting the mass of the weight and the mass of the luggage loaded on the carriage. The movable object is towed by a dolly that moves at a constant speed and is initially accelerated, but after a few seconds, the movable object slides in the channel at the same constant speed as the dolly. In this state, the tension gauge measures the tension applied to the nylon line, that is, the forward force applied to the movable object. The moving speed of the carriage or the movable object was made extremely small so that the flow resistance of the lubricating liquid with respect to the movable object was reduced to a level that was substantially negligible with respect to the friction resistance (for example, 1 cm / sec or less). .

  In Table 2 below, the present inventor uses the dynamic friction coefficient measuring device shown in FIGS. 5 (a) to 5 (c) to measure a moving object in a room at room temperature (25 ° C.) or a movable object in the case where a calculated PANa solution is present.・ Indicates the coefficient of dynamic friction between channels. In Table 2, for reference, the dynamic friction coefficient between the movable object and the channel when the lubricating oil intervenes and the lubricating liquid measured or calculated by the present inventor in the same manner as in the case of the PANa aqueous solution are shown. The coefficient of dynamic friction when there is no interposition is also shown.

  FIG. 6 is a graph prepared based on the data shown in Table 2 and showing the relationship between the coefficient of dynamic friction between a movable object and a channel when a water-based lubricating liquid is present and the amount of PANa added to water in the water-based lubricating liquid. As is clear from FIG. 6, the coefficient of dynamic friction is 0.02 or less when the amount of PANa added to water is in the range of 0.5 to 5.0 wt%. As described above, when the lubricating liquid is present between the gears of the gear device, the coefficient of dynamic friction in sliding friction between the gears may be practically 0.02 or less in practice. Therefore, the water-based lubricating liquid in which the amount of PANa added to water is 0.5 to 5.0 wt% has a friction reducing property suitable as a lubricating liquid for a gear device. As described above, in order to make the kinematic viscosity of the water-based lubricating liquid equal to that of the lubricating oil, the amount of PANa added to water may be adjusted within the range of 1 to 5 wt%. Of course, it has suitable friction reducing properties.

In general, devices or members (components) that form a gear device are formed of iron-based materials (eg, soft iron, steel, stainless steel, etc.) or aluminum-based materials (eg, aluminum, aluminum alloys, etc.). Then, the iron-based material and the aluminum-based material may be corroded by hydrogen ions (H ⁺ ) when they come into contact with an acidic liquid. Further, the aluminum-based material may be corroded by hydroxide ions (OH ⁻ ) when contacted with an alkaline liquid having a hydrogen index of more than pH 11. Therefore, the hydrogen index of the water-based lubricating liquid is adjusted within the range of pH 7 to 11 by adding sodium hydroxide or acetic acid if necessary.

  The inventor of the present invention observed the presence or absence of corrosion by immersing a sample of pure aluminum in various water-based lubricating liquids having different hydrogen indexes (PANa addition amount: 1 wt%) for 2 weeks, and found that the water-based lubricating liquids of pH 8 to 10 were used. No corrosion of the sample was observed. Therefore, it is particularly preferable that the hydrogen index of the water-based lubricating liquid is in the range of pH 8 to 10 in order to more completely protect the device or member made of the aluminum material. When the gear device is not made of an aluminum material, the hydrogen index of the water-based lubricating liquid may exceed pH 11.

  Since most of the water-based lubricating liquid (generally, 95 to 99 wt%) is water, its freezing point or melting point is almost 0 ° C, but in Japan, the temperature or gear unit temperature may fall below 0 ° C in winter. There is. Therefore, when the gear device is installed in a place where the temperature thereof may be lower than 0 ° C., it is preferable to add propylene glycol or ethanol as an antifreezing agent to the water-based lubricating liquid. Propylene glycol or ethanol as an antifreezing agent is adjusted according to the lower limit temperature of use of the gear device or the water-based lubricating liquid.

  FIG. 7 is a graph showing the relationship between the freezing point (melting point) and the concentration in a propylene glycol aqueous solution and an ethanol aqueous solution. The addition amount of propylene glycol or ethanol as an antifreezing agent is set based on the lower limit temperature of use of the gear device or the water-based lubricating liquid and the freezing point of the propylene glycol aqueous solution or ethanol aqueous solution shown in FIG. Specifically, the amount of propylene glycol or ethanol added to water in the water-based lubricating liquid is a temperature range lower than 0 ° C. and the use of a gear device preset within a temperature range higher than the freezing point of propylene glycol or ethanol. The amount of propylene glycol added or the amount of ethanol added to water in the propylene glycol aqueous solution or ethanol aqueous solution having the lower limit temperature as the freezing point is preferably the same as or slightly higher than this. The water-based lubricating liquid containing propylene glycol as an antifreezing agent has a high viscosity at a low temperature lower than 0 ° C, especially near the freezing point.

Hereinafter, the characteristics, performance, etc. of the water-based lubricating liquid according to the present invention and the lubricating oil containing mineral oil as a main component will be compared.
(1) Compressibility It is essential that the lubricating liquid is incompressible, but both the water-based lubricating liquid and the lubricating oil are incompressible, and there is no inferiority between them.

(2) Kinematic Viscosity The kinematic viscosity of the lubricating liquid at 40 ° C. is generally within the range of 20 to 165 mPa · s, but in the water-based lubricating liquid, the kinematic viscosity is adjusted by the amount of PANa added to water. Therefore, basically, if water and PANa are prepared, an aqueous lubricant having a desired kinematic viscosity can be produced. On the other hand, in the case of lubricating oil, the kinematic viscosity is adjusted by mixing various types of mineral oils with different kinematic viscosities, so unless various types of mineral oil are prepared, it is necessary to produce a lubricating oil with a desired kinematic viscosity. I can't. The lubricating liquid preferably has a small change in kinematic viscosity with temperature. As is clear from FIG. 4, the temperature change of the kinematic viscosity of the water-based lubricating liquid is much smaller than the temperature change of the kinematic viscosity of the lubricating oil. Therefore, in terms of kinematic viscosity, water-based lubricating liquids are clearly more advantageous than lubricating oils.

(3) Friction reduction characteristics (dynamic friction coefficient)
According to an experiment conducted by the inventor, the dynamic friction coefficient of sliding friction between gears in which a water-based lubricating liquid having a PANa addition rate of 1 to 5 wt% is present is 0.01 to 0.02 (practically appropriate. Value), especially 0.01 for a water-based lubricating liquid having a PANa addition rate of 1 to 2 wt%. On the other hand, the dynamic friction coefficient of sliding friction between gears in which lubricating oil is present is estimated to be 0.01. Therefore, it can be said that the friction reducing property of the water-based lubricating liquid is almost the same as that of the lubricating oil.

(4) Deterioration due to oxidation It is essential that the lubricating liquid is unlikely to deteriorate due to an oxidation reaction (especially at high temperature). The water-based lubricant basically consists of water and sodium polyacrylate, but since sodium polyacrylate does not combine with oxygen below its combustion temperature (several hundreds of degrees Celsius), deterioration of the water-based lubricant due to oxidation occurs. Absent. On the other hand, a lubricating oil composed of mineral oil is inevitably deteriorated by oxidation, and the deterioration rate becomes higher as the temperature rises. In this respect, the water-based lubricating liquid is more advantageous than the lubricating oil.

(5) Metal Corrosion Gear devices are generally made of iron alloys and aluminum alloys, but as described above, the hydrogen index of the water-based lubricating liquid is adjusted within the range of pH 7 to 11 (preferably pH 8 to 10). Therefore, the gear device is hardly corroded by hydrogen ions (H ⁺ ) or hydroxide ions (OH ⁻ ). On the other hand, hydraulic fluids have relatively low metal corrosiveness unless they contain sulfur. Therefore, there is no superiority or inferiority between the two in this respect.

(6) Effect of mixing of water vapor The gear device is a closed system, and has a structure that does not allow foreign matter such as dirt and dust to enter from the outside, but since it is not a completely closed system, water vapor from the atmosphere Can't be prevented. Therefore, in the gear device, water vapor is mixed into the lubricating liquid from the atmosphere. For this reason, deterioration or white turbidity occurs in the lubricating oil. On the other hand, the majority of the water-based lubricating liquid (95 to 99 wt%) is water, so the intrusion of water vapor from the atmosphere does not cause any trouble. In this respect, the water-based lubricating liquid is more advantageous than the lubricating oil.

(7) Possibility of fire Since most of the water-based lubricating liquid is water and nonflammable, there is no possibility of fire occurring in the gear device. On the other hand, since the lubricating oil made of mineral oil is flammable, there is a possibility that a gear device may be fired due to misfire, spread of fire, accident, or the like. In this respect, the water-based lubricating liquid is more advantageous than the lubricating oil.

(8) Toxicity / Environmental Pollution Sodium polyacrylate or polyacrylic acid is used as a thickener in the field of manufacturing foods and cosmetics and has extremely low toxicity to living bodies. Therefore, even if it flows into a river or the like, it does not adversely affect the inhabitants of the basin or the aquatic ecosystem. Further, the water-based lubricating liquid is an aqueous solution, and when it leaks to a river or the like, it is immediately mixed with the water of the river or the like and does not settle on the bottom of the water or float on the water surface. Therefore, even if the water-based lubricating liquid leaks into rivers, lakes and marshes, it is decomposed by the self-cleaning action of the natural world, and its environmental pollution is very low. On the other hand, lubricating oils, which consist mainly of mineral oils and contain various additives, are toxic to living organisms, and when leaked to rivers, lakes, etc., they float on the water surface and significantly deteriorate the water environment. Let In this respect, the water-based lubricating liquid is more advantageous than the lubricating oil.

(9) Behavior of bubbles In general, the lubricating liquid is constantly in contact with the air in the lubricating liquid storage tank, so that the air is dissolved to almost the saturation solubility. Air-saturated solubility changes roughly in proportion to the pressure of the lubricating liquid. For this reason, at a place where the lubricating liquid is in a depressurized state (less than atmospheric pressure) in the lubricating liquid circulation circuit (for example, a pump suction port), some of the air dissolved in the lubricating liquid cannot be dissolved and becomes a very small amount. Bubbles are generated. These bubbles will dissolve in the lubricating liquid when the pressure of the lubricating liquid rises again, but it takes some time for the bubbles to completely dissolve in the lubricating liquid. Therefore, the remaining air bubbles may cause cavitation of the pump or erosion of parts. Under atmospheric pressure, the saturated air solubility of a lubricating oil composed of mineral oil at room temperature is about 9% by volume, but in the case of an aqueous lubricant, it is about 2% by volume. As described above, since the air-saturated solubility of the water-based lubricating liquid is smaller than that of the lubricating oil, the amount of bubbles generated is reduced, and the cavitation of the pump and the erosion of parts are reduced. In this respect, the water-based lubricating liquid is more advantageous than the lubricating oil.

(10) Biological deterioration (rotting)
Sodium polyacrylate or polyacrylic acid, which is the main raw material of the water-based lubricating liquid, is an organic compound containing carbon, hydrogen or oxygen, and basically can be a nutrient source for microorganisms. Therefore, when nitrogen compounds, phosphorus compounds, etc. necessary for the growth of microorganisms are sufficiently supplied, the aqueous lubricant may be biodegraded (rotted) by the microorganisms. However, since there is no possibility that nitrogen compounds, phosphorus compounds, etc., which are essential for the growth of microorganisms, will invade the gear device, which is an almost closed system, there is no possibility that ordinary microorganisms will grow in the water-based lubricating liquid, No biological deterioration (rotation) of the water-based lubricating liquid occurs. When the water-based lubricating liquid is discharged into rivers, lakes and marshes, a large amount of nitrogen compounds, phosphorus compounds, etc. are present in the outside world, so that the water-based lubricating liquid is biodegraded. On the other hand, lubricating oils do not biodegrade (rot).

  As mentioned above, the raw materials of the water-based lubricating liquid other than water are sodium polyacrylate, polyacrylic acid, propylene glycol, ethanol, sodium hydroxide, acetic acid, etc., but these raw materials are toxic or harmful to the human body or the living body. It has almost no sex and is used as a food or its additive. The legal restrictions on these raw materials are explained below.

(1) Sodium polyacrylate or polyacrylic acid Sodium polyacrylate or polyacrylic acid is a synthetic drug, but the toxicity or harm to the living body is extremely low, and the quality is sodium polyacrylate or polyacrylic acid of food additive level. Acrylic acid is used as a thickener in the food field. The use of sodium polyacrylate or polyacrylic acid is not legally regulated in terms of biological protection.

(2) Ethanol Ethanol is a main component of alcoholic beverages (alcoholic beverages) and is used as a medicine, and has extremely low toxicity or harmfulness to the living body.

(3) Propylene glycol Propylene glycol is used as a quality improving agent in medicines, cosmetics, and foods such as noodles and cooked rice, and has extremely low toxicity or harmfulness to living bodies. Propylene glycol is classified as a dangerous substance class 4 by the Fire Service Law because it is flammable, but the propylene glycol concentration of the water-based lubricating liquid is much lower than the flammability limit concentration. Therefore, the water-based lubricating liquid is not regulated by the Fire Service Act due to containing propylene glycol.

(4) Sodium hydroxide Sodium hydroxide is ionized into sodium ions (Na ⁺ ) and hydroxide ions (OH ⁻ ) in water, and alkalinity becomes stronger when the hydroxide ion concentration in water is high. Both ions are originally present in the living body and are not toxic or harmful to the living body as a substance. Therefore, apart from the point of being regulated based on pH, the use of sodium hydroxide itself is not legally regulated from the viewpoint of protecting the living body.

(5) Acetic acid Acetic acid is a main component of vinegar used as a food and has extremely low toxicity or harmfulness to the living body.

  Such water-based lubricants that do not contain harmful substances are discharged into water bodies or discarded after the end of their useful life, but if they are discharged into public water bodies (rivers, lakes, seas), water pollution will occur. It may be regulated by the Prevention Law or its supplementary regulations, and when discharged into public sewers, it may be regulated by the Sewerage Law or its supplementary regulations. The Water Pollution Control Act or the Sewerage Act or its addition ordinance states that if the discharged water or sewage discharged from business sites contains prescribed harmful substances (28 types) related to health items, regardless of the amount of discharge , The concentration of harmful substances in discharged water or sewage is regulated to be below the emission standard.

On the other hand, regarding the quality of discharged water or sewage related to living environment items that is not directly toxic or harmful to living organisms, the average daily discharge of discharged water or sewage is defined by the Water Pollution Control Act or the Sewer Act. For business establishments with a volume of less than 50 m ³ , the emission is not regulated at all. In addition, if the average daily discharge of discharged water or sewage is 10 m ³ or more, some prefectures regulate the discharge according to the regulations.

The water-based lubricant does not contain any harmful substances related to health items stipulated by the Water Pollution Control Act or the Sewer Act. Further, in the gear device using the water-based lubricating liquid, the water-based lubricating liquid is circulated and used, and after the service life has passed, about 1 to 5 m ³ of the water-based lubricating liquid is simply discharged to the public water area or the public sewer. Therefore, even in prefectures to which the strictest addition standard is applied, it is possible that an average of 10 m ³ or more of discharged water or sewage per day will be discharged to public water bodies or public sewers from gear devices that use water-based lubricants. There is none. Therefore, in the gear device using the water-based lubricating liquid, when the water-based lubricating liquid is discharged into the public water area or the public sewer, there is no regulation under the Water Pollution Control Act or the Sewerage Act or its regulations.

S gate opening / closing device, 1 gate, 2 doors, 3 wire rope,
4 wire drums, 5 rotating shafts, 6 drum support parts, 7 connecting tools,
8 gear type speed reducer, 9 output shaft, 10 housing,
11 input shaft, 12 1st intermediate shaft, 13 2nd intermediate shaft,
14 3rd intermediate shaft, 15 1st gear, 16 2nd gear,
17 3rd gear, 18 4th gear, 19 5th gear, 20 6th gear,
21 7th gear, 22 8th gear, 25 electric motor, 26 conducting wire,
27 control panel, 30 lubricating liquid supply device, 31 lubricating liquid supply device, 32 nozzles,
33 lubricating liquid storage tank, 34 lubricating liquid return passage, 35 lubricating liquid discharge port,
36 lubricant receiving port, 37 pump, 38 lubricant supplying passage.

Claims (7)

Housing,
A gear type power transmission mechanism having a plurality of gears respectively arranged in the housing and meshing with each other or sequentially;
A first shaft connected to a predetermined gear of the gear type power mechanism and protruding to the outside of the housing;
A second shaft connected to a gear other than the predetermined gear and protruding to the outside of the housing;
A gear device comprising a lubricating liquid supply means for supplying an aqueous lubricating liquid to the gear type power transmission mechanism,
The water-based lubricating liquid contains water and sodium polyacrylate, and the amount of sodium polyacrylate with respect to water in the water-based lubricating liquid is in the range of 1 to 5 mass%,
A gear device, wherein the hydrogen index of the water-based lubricating liquid is within a range of pH 7 to pH 11.   The gear device according to claim 1, wherein a hydrogen index of the water-based lubricating liquid is within a range of pH 8 to pH 10.   The gear device according to claim 1 or 2, wherein the hydrogen index of the water-based lubricating liquid is adjusted by adding sodium hydroxide or acetic acid. The gear type power transmission mechanism is a parallel type gear mechanism in which each shaft supporting the plurality of gears is arranged in parallel,
The first shaft is an input shaft for inputting power to the parallel gear mechanism,
The gear device according to any one of claims 1 to 3, wherein the second shaft is an output shaft that outputs power from the parallel gear mechanism. The gear type power transmission mechanism is a planetary gear mechanism,
The first shaft is an input shaft for inputting power to the planetary gear mechanism,
The gear device according to claim 1, wherein the second shaft is an output shaft that outputs power from the planetary gear mechanism.   The water-based lubricating liquid contains propylene glycol, and the amount of propylene glycol added to water in the water-based lubricating liquid is preset within a temperature range lower than 0 ° C. and higher than the freezing point of propylene glycol. The amount of propylene glycol added to water in the propylene glycol aqueous solution having the freezing lower limit temperature as the freezing point is equal to or more than that, and the gear device according to any one of claims 1 to 5.   The water-based lubricating liquid contains ethanol, and the amount of ethanol added to water in the water-based lubricating liquid is set to be lower than 0 ° C. and lower than the freezing point of ethanol. The gear device according to any one of claims 1 to 5, wherein the amount is equal to or more than the amount of ethanol added to water in the aqueous ethanol solution having a temperature as a freezing point.

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