JPH0794098B2 - Water supply device for cutting oil - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a water supply device for cutting oil, and more specifically, as a fire prevention measure in cutting, water is supplied to a cutting surface to supply cutting oil. The present invention relates to a water supply device for keeping a water content constant.

[Conventional technology]

In the recent metal cutting technology (including grinding), as the performance of machine tools has improved, various cutting such as increasing the rotation speed and feed speed of cutting tools or workpieces or increasing the depth of cut Conditions are getting severer. Further, the work itself is often made of a difficult-to-cut material such as stainless steel, heat resistant steel, and titanium alloy. And due to such environmental changes, in recent cutting work,
The rise in cutting temperature due to friction and deformation has become remarkable.

On the other hand, cutting oil is used in the cutting work for the purpose of improving the workability of cutting work, and the cutting oil is roughly classified into water-soluble cutting oil and water-insoluble cutting oil. Of these, the water-insoluble cutting oil is superior in terms of the basic performance required of the cutting fluid, that is, the improvement of the finishing accuracy of the cut finished surface, the reduction of frictional heat or the protection of tools.
From the viewpoint of workability and work efficiency, the use of water-insoluble cutting oil is the mainstream at present.

[Problems to be Solved by the Invention]

By the way, since this water-insoluble cutting oil is flammable, the cutting temperature is becoming extremely high as described above, and the use of water-insoluble cutting oil always involves a risk of fire. Can be said to be.

Moreover, at the actual cutting site, the adoption of NC (numerical control) and FMS (flexible manufacturing system) is increasing the number of labor-saving and unmanned machines and factories. Even if
There are problems such as delays in discovering and responding to such problems, and there is a situation in which machines and factories are damaged by a fire.

In this regard, as a fire prevention measure against the actual situation at the cutting site, a method of changing the property of the cutting oil to flame retardant and using it has been recently practiced. As this method, for example, a phosphate ester is used as a base oil to make a flame-retardant cutting oil, or a water-solubilizing agent such as an emulsifier is mixed with a water-insoluble cutting oil, and 4 to 20% of water is added thereto. Then, a cutting surface having no flash point (hereinafter referred to as water-containing cutting oil) is generally used. In particular, the latter water-containing cutting oil is suitable for cutting work because it can prevent fires while maintaining good machinability and is inexpensive. Table 1 shows an example of the formulation of this water-containing cutting oil. Table 2 shows the relationship between the water content of the water-containing cutting fluid and the flash point (in any combination example, the water content was 4%).
Is the critical point at which the flash point occurs.

However, even with this water-containing cutting oil, the desired effect is obtained when water is added, and there is no problem at all, but during use, the water in the water-containing cutting oil evaporates over time, which is why There is a problem that the water content falls below a predetermined value (4% in the case of the above composition) and the inherent flammability of the water-insoluble cutting oil comes out, and further improvement has been demanded.

The present invention has been made in view of such conventional problems, and always keeps the variable water content of the water-containing cutting oil within a certain range, and enables stable fire prevention and stable cutting at the same time. It is an object to provide a water supply device for cutting oil.

[Means for Solving the Problems]

In order to achieve the above object, a water supply device of the present invention is a device for automatically supplying water into an oil tank (5) in a cutting oil supply device for machine tools, the water supply device being connected to a water source. A solenoid valve (18) that opens and closes the water supply pipe in response to energization is provided in the middle of the pipe (15).
The energization is controlled by the control means (20), and the control means starts the energization of the solenoid valve at intervals of the first set time, and then the second set time shorter than the first set time. When the time elapses, the power supply is stopped and the oil tank is intermittently supplied to the oil tank at every first set time.

[Action]

The starting means starts energization of the solenoid valve at intervals of the first set time, and the stop means thereafter causes the second set shorter than the first set time.
The energization is terminated when the set time has elapsed. Therefore, the water supply pipe is opened and closed at intervals of the first set time, and water is intermittently supplied to the oil tank.

As a result, the water-containing cutting oil always compensates for the water-reducing amount (mainly water-reducing water) despite the water-reducing action over time (mainly water-reducing water), so that the desired water content is always kept stable.

〔Example〕

 Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

A cutting oil supply system provided with a water supply device according to the present invention is shown in FIG. 1. The system 1 is specifically a cutting machine 2
For cutting oil supply device 3 and water supply device 4
It consists of and.

The cutting oil supply device 3 is for supplying cutting oil to the cutting machine 2, and includes an oil tank 5, an oil supply pump 6, an oil supply nozzle 7, and the like as main parts. The cutting oil (coolant) used in this example is a water-containing cutting oil having a mixing ratio shown in Table 1.

As shown in FIGS. 1 and 4, the oil tank 5 is composed of storage chambers 5a, 5b, 5c and an oil supply chamber 5d partitioned by a plurality of partition plates 8a, 8b, 8c. In the storage chamber 5a, a continuous recovery oil gutter 9 faces from below the cutting portion 2a of the cutting machine 2, and a filter 10 is provided below the downstream end 9a thereof. Further, the cutting oil suction port 6a of the oil supply pump 6 is immersed in the oil supply chamber 5d. This allows the refueling room
5d from the oil supply pipe 11 to the oil supply nozzle 7, and further from the collecting oil gutter 9 to the filter 10, the storage chambers 5a, 5b and 5c, and then to the oil supply chamber 5d again. Path) is formed. The operation operation of the oil supply pump 6 is performed by the control panel 12 provided in the cutting machine 2.

The water supply device 4 is for automatically supplying water into the water-containing cutting oil stored in the oil tank 3, and as shown in FIG. 1 and FIG. A strainer 16, a pressure reducing valve 17, a solenoid valve 18, a water amount adjusting cock 19, and a control unit (control means) 20 for controlling the opening / closing of the solenoid valve 18 are provided as main components, which are sequentially arranged at various points from the upstream side.

The upstream end nozzle 15a of the water supply pipe 15 is connected to a water pipe (not shown) that is a water source, and the downstream water supply hose 21 is connected to the downstream end nozzle 15b.

The strainer 16 removes foreign substances entering from the water pipe to prevent malfunction of the valves 17, 18 and 19 provided in the water supply pipe 15, and the upstream end of the water supply pipe 15. It is provided in the section.

The pressure reducing valve 17 functions as a constant pressure valve for preventing the water pressure of tap water from fluctuating. In other words, the water pressure of tap water differs depending on the municipality, and also varies depending on the usage status of the water around the factory where the cutting machine 2 is installed and the position of the factory, and there is considerable fluctuation (see Table 3, for example). By valve 17,
This water pressure fluctuation disappears to a minimum and completely.

If the pressure reducing valve 17 has a strainer function,
The strainer 16 can be omitted.

Reference numeral 22 is a water pressure gauge for checking whether or not the pressure reducing valve 17 is normally operating, and is provided on the downstream side of the pressure reducing valve 17.

The electromagnetic valve 18 is for opening and closing the water supply pipe 15, and its opening / closing control is performed by the control unit 20 in synchronization with the operation timing of the cutting oil supply device 3. The setting of the operation timing will be described in detail later.

The water amount adjusting cock 19 is for adjusting the amount of water flowing through the water supply pipe 15, and while considering various conditions that affect the amount of water reduction (mainly water evaporation amount) from the water-containing cutting oil, the solenoid valve 18 is used. It is operated manually as appropriate in relation to the opening time. A finely adjustable water amount adjustment cock 19 is desirable in order to improve the adjustment accuracy by manual operation.

The adjustment of the water amount adjusting cock 19 is performed in relation to the operation timing of the solenoid valve 18. In the adjustment, the water content of the water-containing cutting oil in the oil tank 5 is precisely measured for several days, and the measurement result is obtained. Calculate the average amount of water reduction per unit time from and adjust the amount of water supply corresponding to this result.

The water supply hose 21 has its proximal end 21a connected to the downstream end nozzle 15b of the water supply pipe 15 and its distal end nozzle 2
1b faces the oil supply chamber 5d of the oil tank 5. As the water supply hose 21, a hose having oil resistance is preferably used.

In addition, the water supply point by the water supply hose 21 is connected to the oil supply chamber 5d.
This is because a slight amount of water is gradually added at the cutting oil suction port 6a of the oil supply pump 6 because the mixing ratio of water and cutting oil is the best. By the way, the results of investigating the place of addition of water and the mixing condition of water are as shown in Table 4. From these results, the farther from the cutting oil suction port 4a, the greater the amount of water precipitation and the above mixing ratio. It turns out that it will decrease.

The control unit 20 is for controlling the opening and closing of the solenoid valve 18,
Specifically, it comprises a first timer 23 and a second timer 24.
The first timer 23 is for controlling the operation interval of the solenoid valve 18, while the second timer 24 is for controlling the operation time (valve opening time) of the solenoid valve 18.

Next, setting of the operation timing of the solenoid valve 18 will be described.

The setting of the operation timing of the solenoid valve 18 is performed in consideration of the relationship with the opening degree of the water amount adjusting cock 19, but its setting criterion is the evaporation of water, which is a disadvantage of the wet cutting surface. The first purpose is to prevent the flash point from decreasing, and the cutting is carried out within a range in which the original performance as a cutting fluid is not impaired.

That is, if the water content of the water-containing cutting oil is too low, it is inflammable and dangerous. By the way, the conditions that affect the amount of water reduction (mainly the amount of water evaporation) are the working atmosphere temperature, the operating conditions of the cutting machine 2, the temperature of the cutting part 2a during cutting,
There are a surface area of a work to which cutting oil is applied, a shape size of the oil tank 5, and the like.

Conversely, if the water content is too high, it is difficult to maintain the original performance as a cutting fluid, and the viscosity of the cutting fluid itself increases. Specifically, i) lubricity cannot be exerted as the initial design of the cutting oil due to an increase in non-lubricating water, ii) tool damage due to excessive cooling, iii) there is a difference depending on the content of the additive The problem is that the viscosity of the cutting oil increases due to the water content, which causes a burden on the oil supply pump 4 and the discharge pressure is insufficient. By the way, the relationship between the water content and the viscosity in the water-containing cutting oil having the blending ratio shown in Table 1 is as shown in Table 5.

Therefore, the operation timing of the solenoid valve 18 may be set so that the water content is maintained within the range where these disadvantages do not occur. For example, in the case of the water-containing cutting oil having the mixing ratio shown in Table 1, the first timer 23 of the control means 20 is used.
The second timer 24 is operated at the operation timing shown in FIG. 3 in synchronization with the operation timing of the oil supply pump 6 of the cutting oil supply device 3.

That is, the first timer 23 starts timing at the same time as the power supply to the fuel pump 6 is turned on, and keeps the switch on for 12 seconds every 6 minutes. On the other hand, the second timer 24 starts timing at the same time when the first timer 23 is switched on and keeps the switch on for 3 seconds. With these two timers 23,
The solenoid valve 18 opens the water supply pipe 15 for 3 seconds every 6 minutes after the operation of the fuel pump 6 is started, and the oil tank 5 is intermittently supplied with the amount of water set by the water amount adjusting cock 19. It will be (100cc water supply every 6 minutes).

In this embodiment, the first timer 23 and the second timer
With 24, the operation interval can be set to 6 minutes, and
This is because there is no timer on the market that can set the operating time to 12 seconds or less. That is, in order to realize a control means for energizing the solenoid valve 18 by performing an ON operation every 6 minutes for 3 seconds, a second timer 24 whose ON time is set to 3 seconds is used separately from the first timer 23. There is.

In the present embodiment, the first timer 23 is a twin timer (trade name: 3HBF) manufactured by OMRON Corporation, and after the power is turned on, T ₁ (= 6)
Every minute), the first contact turns on, and the second contact turns on in response to the turning on of the first contact and keeps that state for T ₂ (= 12 seconds) before returning to the off state. Become. Therefore, the first
The voltage shown in FIG. 3 is output to the output terminal A ₁ of the timer 23.

On the other hand, the second timer 24 is a 30-second timer (Omron Corporation) that can set the ON time T ₃ within a range of 30 seconds, and in this example, the ON time is set to 3 seconds. The second timer 24
When the voltage of the output terminal A ₁ rises, the voltage is transmitted to the solenoid valve 18 and the voltage is transmitted to the solenoid valve 18 after 3 seconds have passed since it is turned on when the power is turned on and the state is maintained for T ₃ It will return to the OFF state (see Fig. 3). After 12 seconds have passed from the start of the operation, the second timer 24 is de-energized, so that the second timer 24 returns to the initial state.

Since the switch S is a switch used when the ON time T ₃ of the second timer 24 is appropriately changed to check the water supply amount, the switch S is always in the illustrated state when the device is in the operating state. is there.

Then, in the cutting oil supply system 1 configured as follows, the cutting oil supply device 3 and the water supply device 4 operate as follows.

Cutting oil supply device 3: Simultaneously with the start of operation of the cutting machine 2, the control panel 12 is operated to operate the oil supply pump 4 of the cutting oil supply device 6.
Then, the water-containing cutting oil in the oil supply chamber 5d of the oil tank 5 is sucked up from the cutting oil suction port 6a of the oil supply pump 6 and then sent to the oil supply nozzle 7 through the oil supply pipe 11, from which the cutting machine 2 It is supplied onto the work to be cut in the cutting portion 2a of.

The water-containing cutting oil supplied to the workpiece and used is recovered again in the oil tank 5 via the recovery oil gutter 9. The cutting oil collected in the oil tank 5 is filtered by the filter 10 and then flows through the storage chambers 5a, 5b, 5c through the paths indicated by arrows, and is sent to the oil supply chamber 5d again.

Water supply device 4: Simultaneously with the start of the oil supply pump 6 of the cutting oil supply device 3, the first timer 23 and the second timer 24 of the control unit 20 also start timing, and the solenoid valve is operated at the operation timing shown in FIG. Open and close 18 That is, the solenoid valve 18 is, as described above,
After the operation of the fuel pump 6 is started, the water supply pipe 15 is opened every 6 minutes for 3 seconds.

Then, the amount of water set by the water amount adjusting cock 19 is intermittently supplied to the oil tank 5, whereby the cutting portion 2a of the cutting machine 2 is cut off from the oil tank 5.
The water-containing cutting oil supplied to is constantly supplemented with the reduced water content, and the desired water content (around 10 vol%) is stably maintained. Table 6 shows the measurement results.

The present invention is not limited to the above-mentioned embodiment,
Various design changes are possible.

For example, in the illustrated example, even if the solenoid valve 18 is arranged next to the strainer 16, the same effect is obtained. Also, the water pressure gauge 22
Is attached for checking the water pressure and does not directly participate in the water supply, so it can be omitted. Further, in the illustrated example, the water supplied from the water supply device 4 and the oil in the oil tank 5 are naturally mixed so that no special power is required. ), The composition may be more actively mixed.

As for the water supply state when the solenoid valve 18 is opened, continuous supply or drip supply can be adopted by appropriately adjusting the water amount adjustment cock 19.

〔The invention's effect〕

As described above in detail, according to the present invention, a solenoid valve is provided at an intermediate position of the water supply pipe connected to the water source so as to be openable and closable, and the solenoid valve is operated by the control means to operate the cutting oil supply device. Since the opening / closing control is performed in conjunction with the timing, various excellent effects as listed below are obtained, and it is possible to provide a water supply device that enables stable fire prevention and stable cutting at the same time.

(1) A predetermined amount of water is intermittently supplied to the water-containing cutting oil in the oil tank by the opening / closing operation of the solenoid valve. It is supplemented and the desired moisture content is always kept stable.

Therefore, while maintaining the excellent properties of water-insoluble cutting oil as a cutting fluid, its disadvantage is flammability (flammability).
Is also reliably suppressed, and cutting oil can be supplied with less risk of fire.

This effect becomes extremely remarkable at the present time when the cutting temperature rises markedly along with the severer cutting conditions in the metal cutting technology.

(2) In addition, as a result of being able to supply cutting oil with less risk of fire, extremely safe cutting work can be performed even in labor-saving and unmanned machines and factories that employ NC or FMS. it can.

(3) Since the electromagnetic valve can be opened and closed to supply water for a limited time, it is possible to increase the water supply amount per unit time and increase the discharge pressure of the water supply.

Therefore, even when the amount of water supply is very small and dust or scale that cannot be removed by the strainer due to the water quality adheres to the inner wall of each valve of the water supply pipe, etc.
It is possible to completely prevent these dusts and scales from adhering. As a result, it is possible to operate in a maintenance-free state without the need for regular manual cleaning.

(4) Further, since it can be connected to a public or private water supply or an industrial water supply as a water source, a dedicated water tank is not required, and the entire device can be made compact.

(5) Since the solenoid valve is opened and closed in synchronization with the cutting oil supply device and the device operates only when the amount of water reduction is greatest, stable water management of the water-containing cutting oil can be reliably performed, and The running cost of the device is very low and economical.

(6) The control means is composed of a first timer and a second timer, and both of these timers are configured to operate in synchronization with the operation timing of the oil supply pump of the cutting oil supply device, so that the configuration is simple and malfunctions. Also few.

[Brief description of drawings]

FIG. 1 (A) is a schematic perspective view showing a cutting oil supply system provided with a water supply device according to an embodiment of the present invention, and FIG. 1 (B) is a schematic longitudinal sectional view showing the cutting oil supply system. FIG. 2 is a schematic side view showing the water supply device, FIG. 3 is a diagram showing operation timings of the first timer and the second timer of the water supply device, and FIG. 4 is a structure of an oil tank of the cutting oil supply device. It is a schematic longitudinal cross-sectional view shown. 1 …… Cutting oil supply system, 2 …… Cutting machine, 2a ……
Cutting part, 3 ... Cutting oil supply device, 4 ... Water supply device, 5
...... Oil tanks, 5a, 5b, 5c …… Storage rooms, 5d …… Oil supply rooms, 6
…… Oil supply pump, 15 …… Water supply pipe, 16 …… Strainer, 17 …… Pressure reducing valve, 18 …… Solenoid valve, 19 …… Water quantity adjusting cock, 20 …… Control means (control section), 21 …… Water supply Hose, 23
...... First timer, 24 ...... Second timer

Claims (1)

[Claims] 1. A device for automatically supplying water into an oil tank (5) of a cutting oil supply device for a machine tool, wherein electricity is supplied to an intermediate point of a water supply pipe (15) connected to a water source. Is provided with a solenoid valve (18) for opening and closing the water supply pipe, and the solenoid valve is controlled in energization by a control means (20), and the control means is configured to operate at the first set time interval. The solenoid valve includes a start unit that starts energization and a stop unit that ends energization when a second set time shorter than the first set time elapses thereafter. With this configuration, the oil tank is set to the first set time. Water supply device for cutting oil, which is designed to supply water intermittently every hour.