JPH0661479B2 - Roller mill hydraulic circuit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hydraulic circuit of a roller mill.

[Prior Art] Conventionally, a roller mill as a device for pulverizing raw materials is
It has a crushing table which rotates around the vertical axis and a roller provided on this table. The raw material supplied on the table is crushed by being pinched by the upper surface of the table and the rollers.

In this way, the roller is supported by the hydraulic cylinder so as to be vertically movable, and in order to pinch the raw material with a large force,
The roller is pressed against the table by this hydraulic cylinder.

In the above-mentioned configuration, the hydraulic circuit for operating the hydraulic cylinder includes a Japanese Patent Laid-Open No. 62-33556 filed by the applicant of this patent.
JP-A-63-51956 and JP-A-63-51956.

Examples of these conventional hydraulic circuits are shown in FIG. 2 and FIG.
The following is introduced with reference to the figures.

First, the first conventional example disclosed in JP-A-62-33556 will be described with reference to the hydraulic circuit diagram shown in FIG. Piston in a hydraulic cylinder (10) that supports the vertical movement of the
A pressure oil supply switching means (18) for supplying oil to the first hydraulic chamber (14) and the second hydraulic chamber (15) partitioned by (13) is provided. A gas-filled accumulator (22) is connected to the circuit connecting the second hydraulic chamber (15) and the hydraulic pressure supply switching means (18), and the hydraulic pressure supply switching means (18) supplies the first hydraulic pressure to the circuit. Room
From the hydraulic pressure supply switching means (18) to the first circuit (14),
A pilot-type check valve (29b) that allows the pressure oil to flow only to the hydraulic chamber (14) is installed, and opens when the pressure of the pressure oil in the first hydraulic chamber (14) exceeds a predetermined pressure. A relief valve (28a) for valve communication is connected to the first hydraulic chamber (14).

The second conventional example disclosed in Japanese Patent Laid-Open No. 63-51956 will be described with reference to the hydraulic circuit diagram of FIG. ) Of the hydraulic cylinder (10) that supports up and down freely.
A hydraulic pressure supply switching means (18) for supplying oil to the first hydraulic chamber (14) and the second hydraulic chamber (15) partitioned by is provided. Also,
In the circuit that communicates from the second hydraulic chamber (15) to the oil reservoir (17), the first
A pilot-type check valve (36) for circulating pressure oil only to the hydraulic chamber (14) is provided, and a gas-filled accumulator (42) is connected.

Therefore, in any of the above hydraulic circuits, when the pressure oil is supplied to the first hydraulic chamber, the roller moves upward, when the pressure oil is supplied to the second hydraulic chamber, the roller moves downward, and then this roller moves to the table. Since the upper surface is pressed, the raw material on this table is pressed and crushed.

[Problems to be Solved by the Invention]

Although the hydraulic circuit of the roller described above is useful as such,
From the viewpoint of the adverse effect on the reliability due to the excessive load on this circuit, there are still problems as described below.

That is, in the first conventional example, when the piston of the hydraulic cylinder is operating when the pilot-type check valve is opened, the moving speed of this piston reaches 500 mm / sec. The supply speed of oil cannot follow the moving speed of this piston, and as a result, the pressure of the pressure oil becomes a negative pressure state, starting with the air premixed in this oil, and gas is generated. As a result of the adverse effect of the mixture composed of oil on each hydraulic device provided in the hydraulic pressure switching supply means, there is a problem that troubles such as breakage occur in these.

A hydraulic circuit according to a second conventional example was invented to avoid such a problem.

That is, in this circuit, although the supply of the pressure oil follows the moving speed of the piston of the hydraulic cylinder due to the presence of the accumulator provided in the circuit that communicates from the first hydraulic chamber to the oil reservoir, Since the pressure oil is full, the circuit vibration may occur due to the collision of the oil in the piping caused by the random operation of multiple cylinders, and the resonance of the piping system and the hydraulic equipment caused by the vibration may occur. There has been a problem that the hydraulic circuit is adversely affected by the action of an excessive load such as surge pressure.

Therefore, it is an object of the present invention to provide a hydraulic circuit for a roller mill which does not exert an excessive load on the hydraulic circuit of the hydraulic cylinder for operating the roller up and down.

[Means for Solving the Problems]

The present invention has been made to solve the above-mentioned problems, and is therefore characterized in that a plurality of crushing rollers are provided above a crushing table rotating about a vertical axis, and the rollers are hydraulically operated. The roller is supported so as to be movable up and down by a cylinder, and the roller is interlocked with the operation of the piston by the pressure oil supply to the second hydraulic chamber of the first hydraulic chamber and the second hydraulic chamber partitioned by the piston of the cylinder. In the hydraulic circuit of the roller mill that presses the raw material on the crushing table, gas is introduced into the first hydraulic chamber during crushing by pressing the raw material on the table by the roller.

[Action]

In the present invention, since the hydraulic circuit of the roller mill is configured as described above, the oil in the first hydraulic chamber and the pipe communicating with the first hydraulic chamber is removed and the inside thereof is filled with gas.

〔Example〕

An embodiment of the hydraulic circuit of the roller mill according to the present invention will be described below with the same reference numerals as those of the above-mentioned conventional technique, based on FIG. 1 of the hydraulic circuit diagram.

That is, reference numeral (1) shown in FIG. 1 is a roller mill, and a crushing table driven on a base (2) of the roller mill (1) by a motor (not shown) so as to be rotatable about a vertical axis. (3)
Is provided. Also, on the side of this table (3),
Four pressing devices (5a) to (5d) for pressurizing and crushing the raw material on the table (3) are provided at equal intervals in the circumferential direction with respect to the table (3), and they are It can be operated by two hydraulic circuits. It should be noted that the number of pressurizing devices other than four may be two or three, and since they have the same configuration, one of the pressurizing devices (5a) will be described below.

That is, the pressure device (5a) has a roller (7), and the roller (7) is pivotally supported on the base (2) side so as to be vertically swingable.
A support body (9) is swingably supported on the base (2) by a pivot shaft (8), and the roller (7) is supported on the upper rotating end of the support body (9). Has been done.

A double-acting single-rod hydraulic cylinder (10) is installed between the lower rotating end of the support (9) and the base (2). This cylinder (10) has a bottom-side first hydraulic chamber (14) and a rod-side second hydraulic chamber (15) partitioned by a piston (13), and is connected to the piston (13). The tip of (13a) is pivotally attached to the lower end of the support (9). Also, the cylinder
A hydraulic circuit (18) for supplying oil from the oil sump (17) is connected to (10). This hydraulic circuit (18) has a hydraulic pump (19) and an electromagnetic 4-port 3-position directional control valve (20) that can arbitrarily take the first to third positions U, D and N. That is, when the directional control valve (20) takes the first position U, the hydraulic pump (1
The discharge side of 9) communicates with the first hydraulic chamber (14), and the second hydraulic chamber (15) communicates with the oil reservoir (17). When the directional control valve (20) is in the second position D, the discharge side of the hydraulic pump (19) is communicated with the second hydraulic chamber (15) and the first hydraulic chamber (14).
Is communicated with the oil reservoir (17). Further, when the third position N is taken, it is the position when the power is not supplied and the hydraulic cylinder (10)
Oil does not flow between the oil reservoir and the oil reservoir (17).

In addition, a gas filled accumulator (22) is connected to the circuit that connects the second hydraulic chamber (15) and the directional control valve (20). As is well known, this accumulator (22) has the function of absorbing the pulsation of pressure oil in this circuit, etc., and the case communicating with this circuit and the inflatable and contractible prada provided in the case A gas having a predetermined pressure is filled in the plader. A check valve (30) is provided in the circuit from the directional control valve (20) to the first hydraulic chamber (14) to allow the pressure oil to flow only from the control valve (20) to the first hydraulic chamber (14). In addition, the relief valve (31) that opens when the hydraulic pressure in the first hydraulic chamber (14) becomes equal to or higher than a predetermined value is provided with the check valve (30).
Are connected in parallel. Further, a check valve (32) for circulating pressure oil only from the control valve (20) to the second hydraulic chamber (15) is provided in a circuit from the same-direction control valve (20) to the second hydraulic chamber (15). . Then, from this check valve (32) to the second hydraulic chamber (1
A normally closed first opening / closing valve (34) for opening and closing the circuit leading to 5) toward the oil sump (17) and a throttle valve (35) are provided. Also,
A relief valve (28a) for preventing excessive pressure due to surge pressure of the hydraulic cylinder (10) is connected to the second hydraulic chamber (15), and this valve (28a) is a predetermined valve in the second hydraulic chamber (15). It is designed to open above pressure.

On the other hand, on the discharge side of this hydraulic pump (19), this pump (19)
The relief valve (28b) is connected to prevent the discharge pressure of the valve from becoming excessive, and the directional control valve (20) to the first hydraulic chamber (14)
Relief valve (28
c) is provided. In addition, the first hydraulic chamber (14) and the oil reservoir
A pilot type check valve (36) is provided which connects (17) and blocks discharge of pressure oil from the first hydraulic chamber (14). Further, the check valve (36) and the second hydraulic chamber (15) side are communicated with each other by a pilot circuit (39), and a second opening / closing valve (40) for opening / closing the pilot circuit (39) is provided. This second on-off valve
(40) is a 4-port 2-position directional control valve, which includes a first position C for closing the pilot circuit (39) and this pilot circuit
It can take two positions, the second position O for opening (39). When the hydraulic pressure on the side of the second hydraulic chamber (15) exceeds a predetermined level, the second hydraulic chamber
The on-off valve (40) takes the second position O, and the pressure oil on the second hydraulic chamber (15) side is sent to the pilot type check valve (36), which opens the check valve (36). ing.

Further, a timer (not shown) for supplying compressed air from the compressed air supply source (r) to the first pressure oil chamber (14) at a position close to the connection portion of the circuit communicating with the first oil pressure chamber (14) A compressed air supply circuit in which an electromagnetic on-off valve (p) operated via a valve is interposed is in communication.

The on-off valve (p) can take an X position where it opens and a Y position where it closes. In addition, the check valve (3
In the circuit from 2) to the second hydraulic chamber (15), the second hydraulic chamber (1
The roller (7) detects when the pressure of the pressure oil in (5) is high or low.
A pressure switch (s) that outputs an electric signal indicating that it has come into contact with (3) to switch the second opening / closing valve (40) to the second position O.
Is connected. Next, an operation mode of the hydraulic circuit of the roller mill having the above-mentioned configuration will be described below.

That is, when starting the operation of the roller mill (1),
In order to reduce the starting torque of the drive motor of (3), the roller (7) is once moved upward from the table (7).
Thus, when the roller (7) is moved upward, the direction control valve (20) is set to the first position U. Then, pressure oil is supplied from the hydraulic pump (19) to the first pressure oil chamber (14), while the first opening / closing valve (34) is opened / closed so that the pressure oil is supplied from the first opening / closing valve (34). As it is discharged to the reservoir (17), the roller (7) moves upward.

Then, when the upward movement of the roller (7) is completed, the direction control valve (20) returns to the third position N and the first opening / closing valve (34) is closed, so that the roller (7) moves upward. It is held in the state of being moved to. Next, when the directional control valve (20) is set to the second position D after rotating the table (3), pressure oil is supplied from the hydraulic pump (19) to the second hydraulic chamber (15) and the roller (7). Tries to move downwards.

At this time, since the check valve (30) and the relief valve (31) are closed, the pressure oil is prevented from being discharged from the first hydraulic chamber (14). Increased pressure. After that, when the pressure oil is continuously supplied to the second hydraulic chamber (15), the first hydraulic chamber (14) reaches a predetermined pressure, the relief valve (31) starts to open, and the first hydraulic chamber (14 ) Pressure oil is discharged. Along with this, the hydraulic cylinder (10) is contracted without the piston (13) being suddenly moved downward by the weight of the roller (7), and the roller (7) gradually moves toward the table (3). It will move downward. Therefore, the roller (7) starts to contact the raw material on the table (3). And the roller (7)
When the roller starts pressing the raw material on the table (3), the first hydraulic chamber (14) is kept at a predetermined pressure by the relief valve (31), so the roller (7) for the raw material on the table (3) is The press of is hindered. Therefore, when the pressure oil is supplied to the second hydraulic chamber (15) and the hydraulic pressure in the second hydraulic chamber (15) reaches a predetermined pressure or higher, the hydraulic pressure of the pressure oil is detected by the pressure switch (s). At the same time, since it is input to the second on-off valve (40),
The second opening / closing valve (40) takes the second position O, and the pressure oil on the second hydraulic chamber (15) side flows through the pilot circuit (39) to the pilot type check valve (36) side.

Therefore, the pilot type check valve (36) is opened by this pressure oil, and the pressure oil in the first hydraulic chamber (14) is discharged to the oil sump (17) through this check valve (36). 1 hydraulic chamber
The hydraulic pressure of (14) decreases.

On the other hand, since the opening / closing valve (p) is opened in the X position after a predetermined time by the action of the timer, the compressed air supply source (r)
Compressed air (set pressure; 4 kgf / cm ² ) supplied from the valve is supplied to the first hydraulic chamber (14) through the opening / closing valve (p), and as a result, the pressure in the first pressure oil chamber (14) is increased. The oil is quickly replaced with compressed air.

Therefore, the roller (7) strongly presses the raw material (11) on the table (3) by the hydraulic pressure in the second hydraulic chamber (15) without being hindered by the pressure of the compressed air in the first hydraulic chamber (14). The raw material (11) will be effectively crushed.

And in the above case, the roller (7) moves up and down due to the unevenness of the upper surface of the raw material on the table (3), and the piston (13) moves up and down along with the roller (7) to move the first hydraulic chamber (14). Even if the volume of the first hydraulic chamber (14) expands and contracts, the first hydraulic chamber (14) is filled with compressed air, so the volume of the first hydraulic chamber (14) is expanded and compressed according to the expansion and contraction of the piston ( It easily follows the vertical movement of 13). Therefore, even if the volume of the first pressure oil chamber (14) expands, the first pressure chamber (14) is prevented from becoming negative pressure, and a mixture of air and pressure oil exists. Disappears.

In addition, when raising the roller (7), the electromagnetic on-off valve
(p) and pilot type check valve (36) are closed,
Pressure oil is supplied to the hydraulic chamber (14).

Then, since air is present in the first hydraulic chamber (14), it becomes a mixture of the residual air and pressure oil. At this time, the hydraulic cylinder (10) includes rollers (7) and the like. Although the load based on the gravity of the
There was no problem due to the hydraulic cylinder (10) being operated by this mixture during the upward movement of (7).

In the above description, compressed air is supplied to the first hydraulic chamber (14), but the tip of the circuit from the first hydraulic chamber (14) to the oil sump (17) and the inside of the oil sump (17) By providing a predetermined space between the oil surface and the oil surface, it is possible to replace the pressure oil in the first hydraulic chamber (14) with air, so that an effect equivalent to that of the above-described embodiment can be expected.

However, since it is not a method of forcibly removing the pressure oil in the first hydraulic chamber (14) by supplying compressed air as in the above-mentioned embodiment, it takes a long time to replace it, but, Even if it is not changed, the atmospheric pressure is maintained, so that there is no fear of generation of bubbles or gas.

The above-described embodiments are merely specific examples of the present invention, and therefore, the scope of the technical idea of the present invention is not limited by these embodiments.

〔The invention's effect〕

According to the hydraulic circuit of the roller mill of the present invention, the oil in the first hydraulic chamber and the pipe communicating with the first hydraulic chamber is removed and filled with gas, so that the piston of the hydraulic cylinder moves as in the first conventional example. Since the first hydraulic chamber is filled with gas even at a high speed, there is no fear of generation of air or gas from the pressurized oil. Further, since the first hydraulic chamber is filled with gas as described above, the circuit vibration due to the oil collision in the pipe caused by the random operation of the plurality of cylinders as in the second conventional example, and the The resonance of the piping system caused by this vibration and the effect of excessive load such as surge pressure on each hydraulic equipment are eliminated. Therefore, unlike the prior art, there is no factor that adversely affects each hydraulic device in the hydraulic circuit, and the raw material can be crushed in a stable state for a long period of time.

Furthermore, there is no need to consider excessive load due to vibration of the hydraulic circuit, surge pressure, etc., which not only simplifies the design of the piping, but also has the effect of being economically advantageous from the viewpoint of its strength. Came.

Therefore, according to the present invention, it is possible to realize an extremely excellent and useful hydraulic circuit for a roller mill that does not exert an excessive load on the hydraulic control circuit of the cylinder when the hydraulic cylinder for vertically moving the crushing roller is operated.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a roller mill according to the present invention, FIG. 2 is a hydraulic circuit diagram of a first conventional roller mill, and FIG. 3 is a hydraulic circuit diagram of a second conventional roller mill. (1) …… Roller mill, (3) …… Grinding table, (7) …… Roller, (10) …… Hydraulic cylinder, (11) …… Raw material, (14) ……
First hydraulic chamber, (15) …… Second hydraulic chamber, (36) …… Pilot type check valve, (p) …… Open / close valve, (r) …… Compressed air supply source, (s) …… Pressure switch .

Claims (1)

[Claims] 1. A plurality of crushing rollers are provided above a crushing table rotating around a vertical axis, the rollers are supported by a hydraulic cylinder so as to be movable up and down, and a first hydraulic chamber partitioned by a piston of the cylinder. In the hydraulic circuit of the roller mill in which the roller presses the raw material on the crushing table in conjunction with the operation of the piston by the supply of pressure oil to the second hydraulic chamber of the second hydraulic chamber, A hydraulic circuit for a roller mill, wherein gas is introduced into the first hydraulic chamber during crushing by pressing the raw material.