JPH0130446Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a displacement limiting device that can be applied to a press part vibration prevention device of a paper machine.

(Prior art) Conventional pressure rolls 1 and 2 used, for example, in paper machines, etc., have high circumferential speeds and high pressure forces, so the rubber layer on the roll surface and the felt 3 passing between the rolls are partially damaged. It deforms and generates vibration.
This vibration may cause further deformation of the rubber layer or felt, resulting in large vibrations. Conventionally, as a method for preventing this, a jack bolt 4 as shown in FIG. 4 has been used.

However, during long-term operation, the length l of the jack bolt 4 must be adjusted in response to changes in operating conditions. If the adjustment is not made in this way, for example if the length l is too long, the ratio of the pressure force that should be applied to the rolls 1 and 2 will be increased by the jack bolt 4, and the required pressure force between the rolls 1 and 2 will be increased. You won't be able to get it. Conversely, if the length l is too short, it will not function as a displacement limiting device. In addition, to adjust the length of jack bolt 4,
This is done by relative rotation of the bolt 5 and nut 6.

That is, the jack bolt 4 is connected to the bolt 5 and nut 6.
By adjusting the length to correspond to the average pressurizing position by relative rotation of Although it does not offer any resistance to movement in the opposite direction, it has the drawbacks mentioned above.

In order to eliminate vibrations in the pressure roll system used in the press section of paper machines, etc., there is no problem if there is a rubber material or felt that can withstand high circumferential speeds and high shear forces.
Today's high-speed paper machines and the like require measures to prevent vibration from a mechanical standpoint.

(Problems to be Solved by the Invention) The present invention attempts to solve the conventional problems of vibration generation by preventing vibration from a mechanical perspective as well.

(Means for solving the problem) Therefore, in the present invention, a displacement limiting device installed between two pressure rolls is composed of a hydraulic jack, a solenoid valve, and a hydraulic power source, and a signal to operate the solenoid valve is provided. The electromagnetic valve is equipped with a signal oscillator that oscillates, and the solenoid valve is operated periodically or irregularly by the signal from the oscillator, and during the time period when there is no signal, the hydraulic jack is connected to the hydraulic power source through a pipe line between the hydraulic jack and the hydraulic power source. The height of the hydraulic jack is adjusted by the hydraulic pressure of the hydraulic jack, and during the time when other signals are being oscillated, the discharge of oil from the hydraulic jack is cut off by the solenoid valve, thereby reducing the height of the hydraulic jack. It is equipped with a structure designed to resist.

(Function) In the above configuration, the length of the hydraulic jack automatically changes in accordance with the average pressurized position of the roll during operation, etc., and during the time period when the length is not adjusted, the roll is adjusted to the average pressurized position. It resists movement further in the pressing direction from the pressing position, but does not resist movement in the opposite direction to the pressing direction. Therefore, deformation of the rubber layer and felt does not progress, and vibrations do not occur in the roll system.

(Example) Examples of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show examples of the present invention. Now, in Fig. 1, 1 and 2 are a pair of pressure rolls,
The roll 1 is supported by a pressure arm 8 via a bearing housing 7, and the roll 2 is supported by a bearing housing 10 integrated with a frame 9. Felt 3 then passes between rolls 1 and 2.

The pressure arm 8 is supported by the frame 9 via a shaft 26, and is rotated about the shaft 26 by the pressing force of the bellows frame 27, thereby pushing the roll 1 into the roll 2.
Crimp. As shown in FIG. 2, the plunger 13 is pressed upward by hydraulic pressure introduced into the main body case 12. In addition, the pressure set from the air supply source 22 via the pressure reducing valve 36 causes the oil sump 37 to
is pressurized. Oil sump 37 and hydraulic jack 11
In between, there is a relief valve 33 that prevents the oil pressure of the hydraulic jack 11 from exceeding a preset oil pressure, and a solenoid valve 24 that is operated by a signal oscillator 23.

Next, the operation of the embodiment configured as above will be explained. Note that the position of the pressurizing arm 8 when the pressurizing force of the rolls 1 and 2 is set to a predetermined pressurizing force required by the operating conditions will be referred to as the average pressurizing position. This average pressurizing position is determined by the shrinkage of the rubber layer or felt, so if the pressurizing force between the rolls 1 and 2 required by the operating conditions changes, the average pressurizing position will change.

As shown in FIG. 3, the signal oscillator 23 cuts off the signal to the electromagnetic valve 24 for a time to in a ti period. When there is no signal from the signal oscillator 23, the solenoid valve 24 is connected to the conduit between the oil sump 37 and the hydraulic jack 11, and the plunger 13 is pushed upward by the oil pressure of the oil sump 37. At this time, if the height of the hydraulic jack 11 is
If it is lower than the height corresponding to the average pressurizing position, the plunger 13 is moved until it hits the pressurizing arm 8. If the height is higher than the average pressure position, the plunger 13 is moved by the lower surface of the pressure arm 8 against the oil pressure of the oil sump 37, and the hydraulic jack 11 is adjusted to a height corresponding to the average pressure position. be done.

Eventually, after the time to has elapsed, the solenoid valve 24 is brought to the position shown in FIG. Jyatsuki 11
Since it resists the force that tries to reduce the height of roll 1, the displacement is limited so that roll 1 is not pressurized further than the average pressurizing position, but there is no action against movements that would reduce the pressurizing force of roll 1. I don't even resist. The above operation is then repeated every ti period. Note that instead of the oil reservoir 37, it is also possible to connect directly to a hydraulic power source such as a hydraulic pump.

(Effects of the invention) Since the present invention is configured as explained in detail above, when a piece of paper or the like gets caught between a pair of pressure rolls, the movable roll moves in the direction of reducing the pressure. By restricting the roll on the movable side from displacing more than a certain level in the pressure direction, no transient force is applied to the rubber layer or felt of the roll. This prevents the deformation of the roll system from progressing and prevents vibrations in the roll system.

[Brief explanation of the drawing]

Fig. 1 is a side view of a pressure roll of a paper machine or the like using a displacement limiting device showing an embodiment of the present invention, Fig. 2 is a circuit diagram of the displacement limiting device, and Fig. 3 is a signal oscillator in Fig. 2. is an explanatory diagram showing a state in which the signal to the electromagnetic valve is cut off for a period of to at a period of ti, and FIG. 4 is a side view of a pressure roll of a conventional paper machine or the like. Explanation of the main parts of the figure, 1, 2...pressure roll,
11...Hydraulic jack, 13...Plunger, 2
3...Signal oscillator, 24...Solenoid valve, 37...Oil sump (hydraulic source).

Claims (1)

[Scope of utility model registration request] A displacement limiting device installed between two pressure rolls is composed of a hydraulic jack, a solenoid valve, and a hydraulic power source, and is equipped with a signal oscillator that oscillates a signal to operate the solenoid valve. The valve is operated periodically or irregularly, and when the signal is not present, the height of the hydraulic jack is adjusted by the hydraulic pressure of the hydraulic source through a pipeline between the hydraulic jack and the hydraulic source, and other signals are activated. A displacement limiting device characterized in that during a time period when the hydraulic jack is oscillating, the discharge of oil from the hydraulic jack is blocked by the solenoid valve, thereby resisting a force that attempts to reduce the height of the hydraulic jack.