JPS6351954A - Hydraulic circuit for roller mill - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a hydraulic circuit for a roller mill.

(Prior Art) Conventionally, a roller mill as a device for pulverizing raw materials has a pulverizing table that rotates around a vertical axis and a plurality of rollers provided on the table along the circumferential direction of the table. The raw material supplied onto the table is crushed by being pinched between the top surface of the table and each roller.

The roller is vertically movable by a hydraulic cylinder that expands and contracts with pressure oil supplied from a hydraulic pump. When starting the operation of the roller mill, in order to reduce the starting torque of the table drive motor, the roller is first moved upward from the table, and then moved downward after the table has rotated to some extent. Further, in order to compress the raw material with a large force, the roller is pressed against the raw material layer on the table by a hydraulic cylinder using pressure oil from the hydraulic pump.

In the above configuration, the hydraulic pump that supplies pressure oil to the hydraulic cylinder is used to move the roller up and down on the table, and is also used to press the roller onto the table. In this case, since it is necessary to press the roller onto the table with a large force, the hydraulic pump that supplies pressure oil to the hydraulic cylinder is a high-pressure pump.

(Problems to be Solved by the Invention) By the way, if a high-pressure pump has a large discharge volume, the pump becomes extremely large and expensive, so there is a limit to the discharge volume of this hydraulic pump.

Therefore, it takes a long time to move the roller up and down. Here, for example, if it takes a long time for the roller to move downward, the layer of raw material supplied onto the table becomes too thick before the roller moves downward to a predetermined position n on the table, and the downward movement of the roller is restricted. Therefore, there is a possibility that the operation of the roller mill will be hindered.

In addition, since it takes a long time to move each roller up and down,
The difference in the timing of the vertical movement of these rollers becomes large. Therefore, each roller moves downward to a predetermined position,
This is undesirable because it takes a long time for the roller mill to return to its normal operating state, and undesirable products may be formed during this long period of time until the roller mill returns to its normal operating state.

(Objective of the Invention) This invention was made in view of the above-mentioned circumstances, and it is possible to quickly move the roller up and down on the table without reducing the pressing force of the roller against the raw material on the table. The purpose is to make the timing of the vertical movement of each roller as uniform as possible.

(Structure of the Invention) The present invention for achieving the above object is characterized in that a low-pressure pump and a high-pressure pump are provided in parallel to supply pressure oil to hydraulic cylinders that move each roller up and down, and The point is that an on-off valve is interposed in the oil path connecting the cylinder and the above-mentioned two pumps.

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

(First example) FIG. 1 shows a first embodiment.

In the figure, l is a roller mill, and a crushing table 3 is provided on a base 2 of the roller mill l so as to be rotatable around a vertical axis, and this table 3 is rotationally driven by a motor (not shown). Additionally, four pressurizing devices 5a to 5d are provided on the table 3 to pressurize and crush the raw material. These pressurizing devices 5a to 5d are arranged at equal intervals in the circumferential direction with respect to the table 3, and can be operated by one hydraulic circuit. Note that the number of pressurizing devices may be two or three in addition to four.

Since each of the pressure devices 2t5a to 5d has the same configuration, only one pressure device 215a will be described.

The pressure device fil 5a has a roller 7, and this roller 7 is pivotally supported on the base 2 side so as to be vertically movable. That is, a support body 9 is rotatably supported on the base 2 by a pivot shaft 8, and the roller 7 is attached to the upper rotation end of the support body 9.
is supported. Further, a double-acting, single-rod type hydraulic cylinder 10 is installed between the lower rotating end of the support body 9 and the base 2.

This hydraulic cylinder 10 has a first cylinder partitioned by a piston 13.
It has a pressure oil chamber 14 and a second pressure oil chamber 15, and the tip of a piston rod 13a connected to the piston 13 is connected to the lower rotation end of the support 9.

Pressure oil supply switching means 18 for supplying oil from the oil reservoir 17 to the hydraulic cylinder 10 is provided. This pressure oil supply switching means 18 has a low-pressure pump 19 with a large discharge amount for moving the roller 7 up and down, and an electromagnetic 4-boat 3-position directional control valve 20 which is an on-off valve. The first to third positions U, D, and N can be arbitrarily taken.

That is, when the directional control valve 20 takes the first position U, the discharge side of the low pressure pump 19 is 1 - foot temperature 1 pressure oil chamber 14
The second pressure oil chamber 15 is connected to the oil reservoir 17. Further, the directional control valve 20 is connected to the second position
If the discharge side of the low pressure pump 19 is
5, and the first pressure oil chamber 14 is connected to the oil 'N1 part 17.
connected to. When the third position N is taken, it is a position when no electricity is applied, and oil does not flow between the hydraulic cylinder 10 and the oil reservoir 17.

On the other hand, a gas-filled accumulator 22 is connected to the oil passage connecting the second pressure oil chamber 15 and the directional control valve 20. This accumulator 22 has the function of absorbing the pulsations of the pressure oil in this oil passage, and is composed of a case communicating with the oil passage, and a bladder that is provided inside the case and can be expanded and deflated. This bladder is filled with gas at a predetermined pressure.

Furthermore, a flow rate synchronization means for synchronizing the flow rate of pressure oil to each second pressure oil chamber 15 is provided. That is, a hydraulic motor 24 is provided between the directional control valve 20 and each pressurizing device 5a to 5d.
are interposed, and these hydraulic motors 24 are interlocked and connected to each other. Further, a first pilot check valve 25 is provided that allows pressure oil to flow from the discharge side of each hydraulic motor 24 only to the second pressure oil chamber 15. Then, when the pressure in the pipe line from the directional control valve 20 to the first pressure oil chamber 14 exceeds a predetermined pressure, this pressure is transmitted to the first pilot type check valve 25 through the pilot oil line 26. Open the valve. Then, the pressure oil in the second pressure oil chamber 15 passes through the first pilot check valve 25 and is discharged to the oil reservoir 17 side.

On the other hand, a check valve 30 that allows pressure oil to flow only from the direction control valve 20 to the first pressure oil chamber 14 is provided in the oil passage from the direction control g94f20 to the first pressure oil chamber 14. Also,
A relief Jj31, which opens when the oil pressure in the first pressure oil chamber 14 exceeds a predetermined level, is connected in parallel to the check valve 30.

A relief valve 28a is connected to the second pressure oil chamber 15 to prevent excessive pressure due to surge pressure of the hydraulic cylinder 10, and this relief valve 28a opens when the pressure of the second pressure oil chamber 15 exceeds a predetermined pressure.

On the other hand, a relief valve 28b is connected to the discharge side of the low pressure pump 19 to prevent the discharge pressure of the low pressure pump 19 from becoming excessive. Further, a relief valve 28c is connected to the discharge side of the hydraulic motor 24.

When starting the operation of the roller mill l having the above configuration, in order to reduce the starting torque of the drive motor for the table 3, -
First, the roller 7 is moved upward from the table 3. When the roller 7 is moved upward in this manner, the directional control valve 20 is set to the first position U. Then, pressure oil is supplied from the low pressure pump 19 to the first pressure oil chamber 14, the piston 13 moves upward, and the roller 7 attempts to move upward.

At this time, the oil pressure in the second pressure oil chamber 15 increases.

In addition, the oil pressure in the first pressure oil chamber 14 increases to counter this.

When the oil pressure in the first pressure oil chamber 14 reaches a predetermined level or higher, each first pilot type check valve 25 opens due to the bi-rotation through the pilot oil passage 26, and each second pressure oil chamber 15 opens.
Pressure oil passes through the first pilot check valve 25, the hydraulic motor 24, and the directional control valve 20 and is discharged to the oil sump 17. As a result, the piston 13 is moved upward, the hydraulic cylinder 10 is extended, and the roller 7 is moved upward. In this case, since the low-pressure pump 19 has a large discharge amount, the extension operation of the hydraulic cylinder 1O is fast, and therefore the upward movement of the roller 7 is performed at a high speed.

After rotating the table 3, when the directional control valve 20 is set to the second position D, pressure oil is supplied from the low pressure pump 19 to the second pressure oil chamber 15, the piston 13 moves downward, and the roller 7 moves downward. try to. At this time, since the check valve r30 and the relief valve 31 are closed,
Discharge of the pressure oil from the first pressure oil chamber 14 is prevented. For this reason,
The pressure on the second pressure oil chamber 15 side increases, and the accumulator 2
The plug in the case at 2 is held in a contracted state against the pressure of the enclosed gas.

Thereafter, when the supply of pressure oil to the second pressure oil chamber 15 continues, the pressure in the first pressure oil chamber 14 reaches a predetermined pressure, the relief valve 31 starts to open, and the pressure oil in the first pressure oil chamber 14 starts to open. It is discharged. As a result, the piston 13 is moved downward, the hydraulic cylinder 10 is contracted, and the roller 7 is moved downward onto the table 3. Therefore, the original document 1 of the table 3'' begins to be pinched between the upper surface of the table 3 and the roller 7. In this case as well, since the low pressure pump 19 has a large discharge rate, the downward movement of the roller 7 is performed at high speed. be exposed.

When the roller 7 moves downward by a predetermined amount, the roller 7 is moved up and down due to the unevenness of the upper surface of the raw material on the table 3, but the second pressure oil chamber 15 is kept in a pressurized state, and therefore, Since the bladder of the accumulator 22 remains deflated, the plug is prevented from colliding with the inner surface of the case of the accumulator 22.

Moreover, in the above case, from the low pressure pump 19 to the second pressure oil chamber 15
When pressure oil is supplied to each hydraulic motor 24, this pressure oil is supplied to each hydraulic motor 24.
However, since these hydraulic motors 24 are connected to each other, the flow rate of the pressure oil passing through each hydraulic motor 24 is synchronized and made equal to each other. Therefore, each pressurizing device 2!5a
The rollers 7 at ~5d will move downward onto the table 3 at the same time.

The pressure oil supply FjJ transfer means also transfers the roller 7, which has been moved downward onto the table 3 as described above, to the table 3.
It is configured to press the upper raw material with a large force.

That is, a high-pressure pump 33 is provided that can supply high-pressure oil although its discharge amount is relatively small. A normally closed first on-off valve 34 and a throttle valve 35 are provided on the discharge side of the high-pressure pump 33 and flJI of each second pressure oil chamber 15, respectively. A relief valve 2 is provided on the discharge side of the high pressure pump 33 to prevent the discharge pressure of the high pressure pump 33 from becoming excessive.
8d is connected.

Also, i2 prevents discharge of pressure oil from the first pressure oil chamber 14.
A pilot type check valve 36 is provided, and this second pilot type check valve 36 and the second pressure oil chamber 15 communicate with each other through a pilot oil passage 39. A second on-off valve 40 that opens and closes this pilot oil passage 39 is provided. This second on-off valve 40 is a 4-port, 2-position directional control valve, with a first position C that closes the pilot oil passage 39;
The second position 0, which opens this pilot oil passage 39, is taken. When the oil pressure on the second pressure oil chamber 15 side reaches a predetermined level or higher, the second on-off valve 40 takes the second position 0, and the second pilot type check valve 36 is opened.

Further, a throttle valve 41 is provided in the pilot oil passage 39, and a check valve 42 is provided in parallel thereto.

Then, when each first on-off valve 34 is opened with the roller 7 moved downward onto the table 3, pressure oil is supplied from the high-pressure pump 33 to the second pressure oil chamber 15 through this, and the roller 7 starts pressing the raw material on table 3. Meanwhile, the low pressure pump 19 is stopped. Furthermore, at this time, the first pressure oil chamber 14 remains closed by the second pilot type check valve 36, so as the pressure oil in the second pressure oil chamber 15 rises, the oil pressure in the first pressure oil chamber 14 also increases. The roller 7 rises and prevents the roller 7 from suppressing the raw material on the table 3.

Therefore, by supplying pressure oil to the second pressure oil chamber 15, this second
When the oil pressure in the pressure oil chamber 15 exceeds a predetermined level, the second on-off valve 40
takes the second position 0, and this! Pressure oil in the 52-pressure oil chamber 15 side flows through the pilot oil passage 39 to the second pilot type two-way valve 36 side. Then, this pressure oil causes the second
The pyro-2 upper check valve 36 is opened. Then, through this second pilot type check valve 36, the first
The pressure oil in the pressure oil chamber 14 is discharged, and the oil pressure in the first pressure oil chamber 14 decreases. As a result, the oil pressure in the first pressure oil chamber 14 is βn
The roller 7 is moved by the hydraulic pressure of the second pressure oil chamber 15 without being harmed.
strongly presses the raw material on the table 3, and the raw material is effectively crushed.

In the above case, since a throttle valve 41 is interposed in the pilot oil passage 39, the pilot pressure oil flows from the second pressure oil chamber 15 side to the second pilot type check valve 36 through this throttle valve 41.
By squeezing 1, it can be made to flow gradually. Therefore, since the opening operation of the second pilot type check valve 36 is also performed gradually, the oil pressure in the first pressure oil chamber 14 does not decrease suddenly. Therefore, the second pilot type check valve 36 is opened. This prevents impact from occurring on the pressure oil supply switching means 18 when the valve is turned on. Furthermore, since the pressing force of the rollers 7 against the table 3 gradually increases, overloading of the motor that drives the table 3 is also prevented.

Also, if the amount of restriction of each of the proof valves 35 is adjusted individually,
The state of pressure applied by each roller 7 to the raw material on the table 3 can be adjusted individually.

The following figures show other embodiments of the invention. Since the configuration and operation of each of these embodiments are almost the same as those of the above-mentioned embodiments, only the different configurations will be explained, and the common configurations will be simply given the same reference numerals in the drawings and their explanation will be omitted.

(Second example) FIG. 2 shows a second embodiment.

In this embodiment, the hydraulic motor 24 and the relief valve 28c in the first embodiment are omitted. Further, the first pyro-2 upper type check valve 25 is single, and this is shared by each of the pressurizing devices r15a to 5d.

The directional control valve 20 and the second pressure oil chamber 15 are connected via a first pilot check valve 25. on the other hand,
The throttle valve 35 in the first embodiment is omitted, and the first
The on-off valve 34 is single. And high pressure pump 3
3 is connected to the second pressure oil chamber 15 via a first on-off valve 34.

(Third example) FIG. 3 shows a third embodiment.

In this embodiment, a throttle valve 4 serving as a flow rate tuning means is used instead of the hydraulic motor 24 and the relief valve 28c in the first embodiment.
3 is provided. By adjusting the throttle valve 43, the inflow speed and outflow speed of the pressure oil into the second pressure oil chamber 15 can be adjusted, and the speed of upward movement and downward movement of the rollers 7 can be adjusted for each roller 7 individually.

(Fourth Embodiment) FIG. 4 shows a fourth embodiment. In this embodiment, the throttle jr43 in the third embodiment is provided for each first pilot check valve 25, and pressure oil is allowed to flow only from the first pilot check valve 25 side to the directional control valve 20 side. The check valve 44 is connected to each of the above calibration valves 4
3 in parallel. In this case, the throttle valve 43 and the check (j 44) constitute flow rate tuning means.

By adjusting the throttle valve 43, the speed of pressure oil flowing into the second pressure oil chamber 15 can be adjusted, and the speed of downward movement of the roller 7 can be adjusted. On the other hand, since the pressure oil from the second pressure oil chamber 15 is discharged through the chain valve 44, the upward movement of the roller 7 is performed at high speed without being affected by the throttle valve 43.

(Fifth Example) FIG. 5 shows a fifth example. In this embodiment, the oil passage from the low pressure pump 19 to the first pressure oil chamber 14 and the oil passage from the low pressure pump 19 to the second pressure oil chamber 15 are connected in reverse. That is, from the low pressure pump 19 to the first pressure oil chamber 1
4, the pressure oil is connected to the hydraulic motor 24 and the first pilot check valve 25 so that the pressure oil passes through the hydraulic motor 24 and the first pilot type check valve 25. Therefore, each roller 7 moves upward from the table 3 at the same timing.

(Effect of invention) This release +! According to II, a low-pressure pump that supplies pressure oil to a hydraulic cylinder and a high-pressure pump are installed in parallel, and an on-off valve is interposed in the oil passage connecting the hydraulic cylinder and both pumps, so that the rollers can be moved on the table. When moving the roller up and down, a low-pressure pump with a large discharge amount is used to speed up the expansion and contraction operation of the hydraulic cylinder, thereby making it possible to quickly move the roller up and down. In this case, since the discharge pressure of the low-pressure pump is low, even if the discharge amount is increased, the pump can be made small and inexpensive.

As described above, since the vertical movement of the roller can be made quickly, for example, firstly, the rotation of the table is started and the raw material is started to be supplied onto this table, and
When the roller is moved down on this table, this downward movement can be done quickly. Therefore, the roller can reach a predetermined height above the table before the raw material layer of the raw material supplied onto the table becomes too thick. As a result, the roller mill can be brought into a normal operating state more reliably.

Second, since the downward movement of the rollers is rapid, the time difference between each roller completing its downward movement is shortened. Therefore, the timing of the downward movement of each roller almost coincides with each other. Therefore, the transition time from the start of operation of the roller mill to normal operation is shortened, and the amount of molded products that are unsuitable to be molded within this transition time can be reduced.

Furthermore, if a 1&gate synchronizing means is provided in the oil passage connecting the hydraulic cylinder and both the low and high pressure pumps, the timing of the vertical movement of the rollers can be more precisely matched.

[Brief explanation of drawings]

The figures show embodiments of the invention, and FIGS.
Hydraulic circuits are shown in each of the embodiments to the fifth embodiment. 10 roller mill, 3...table, 7...roller, lO
・・Hydraulic cylinder, 19・ΦLow pressure pump, 20・・Direction control valve (on/off valve), 24—Hydraulic motor (Ii amount tuning means), 33・・High pressure pump, 34・・1st on/off valve (on/off valve) ), 43-- Throttle valve (flow rate tuning means), 44... Check valve (flow rate tuning unit).

Claims (1)

[Scope of Claims] 1. A roller mill in which a plurality of rollers are provided along the circumferential direction of the table on a crushing table that rotates around a vertical axis, and a hydraulic cylinder that moves each of these rollers up and down is provided, wherein the hydraulic cylinder 1. A hydraulic circuit for a roller mill, characterized in that a low-pressure pump for supplying pressure oil to a roller mill and a high-pressure pump are arranged in parallel, and an on-off valve is interposed in an oil passage connecting a hydraulic cylinder and both pumps. 2. The hydraulic circuit for a roller mill according to claim 1, characterized in that a flow rate tuning means is provided in the oil passage connecting the hydraulic cylinder and both the low and high pressure pumps.