JPH0417852Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a method for quantitatively measuring and displaying the cushion operating state of a hydraulic cylinder used in machine tools, construction machinery, etc., in order to adjust the cushion. The present invention relates to a device for measuring cushion characteristics of a fluid pressure cylinder.

[Prior Art] Hydraulic cylinders, pneumatic cylinders, etc. (hereinafter collectively referred to as fluid pressure cylinders) are used in all industrial fields, but especially when directly transporting a driven object or indirectly linking, When driving a driven body through a mechanism such as a rack and pinion, there are many devices in which it is necessary to stop the driven body without impact at the end of the drive stroke.

In response to such uses, fluid pressure cylinders are generally equipped with a cushion mechanism to reduce the impact when the cylinder reaches the end of its stroke.

As shown in FIG. 3, the hydraulic cylinder 1 includes a piston 4 having a rod 5 slidably provided on the inner circumferential surface 2a of a cylinder tube 2 via seals 3, 3. Cushion rings 6, 6 having a smaller diameter than the piston 4 are formed coaxially, and a rod 5 is fixed to one of the cushion rings 6. The rod 5 is provided in the rod cover 1a and protrudes outward from the cylinder tube 2 from the insertion hole 1b through the seal 7. On the inside of the rod cover 1a, a concave fitting shape that is substantially the same as that of the cushion ring 6 is formed. A chamber 8 is provided at a position facing the cushion ring 6, and the entrance portion 8a of the chamber 8 and the tip 6a of the cushion ring 6 are each provided with an angle of attack. As shown in FIG. 4, a return port 9 is bored in the peripheral wall 8b of the chamber 8, so that it can be connected to a hydraulic device (not shown) via a hose.

Further, a small diameter port 10 is formed in the side wall 9a of the return port 9, and a lock nut 11 is formed in the side wall 9a of the return port 9.
The small-diameter port 10 communicates with the chamber 14 and the return port 9 via a needle throttle valve 13 which is fixedly screwed in from the outer surface of the cylinder tube 2 through a seal 12. In addition,
Although only the rod cover side of the hydraulic cylinder is shown in FIGS. 3 and 4, the structure and function of the head cover side are substantially the same as those of the rod cover side.

In the above configuration, the piston 4 is pressed by hydraulic pressure P from the head side of the piston (not shown), and the rod 5 moves in the direction of arrow A1. At this time, the hydraulic oil on the return side in the hydraulic cylinder 1 is
As shown by arrow A2, it passes through each chamber 14, 8 and returns from return port 9 to a hydraulic device (not shown) via a hose or the like. Rod 5 moves further,
When the cushion ring 6 of the piston 4 enters the chamber 8, as shown in FIG.
Since the hydraulic oil cannot flow into chamber 8,
It flows into the small diameter port 10 and returns to the hydraulic system via the return port 9. At this time, since the hydraulic oil flows through the needle throttle valve 13, the amount of oil passing through it can be adjusted, and the amount of throttle can be fixed by the lock nut 11, so the hydraulic cylinder 1 can be moved from a predetermined position. With a specified cushion stroke, it can be stopped at the end of the stroke without impact.

The mechanism described above absorbs the impact when the cushion ring 6 enters the chamber 8 by the attack angle provided at the tip 6a of the cushion ring 6 and the entrance 8a of the chamber 8, and then the pressure of the chamber 14 is The needle throttle valve 13 is used to soften the sudden rise in the amount of water. This state of shock relaxation is expressed as an s-t diagram in relation to the time axis t and the position s of the piston rod 5 in FIG. 5a. Generally, the needle throttle valve 13 is in the cushioned state.
When fully opened, almost no impact is absorbed as shown by curve α, and rod 5 moves to stop position C. On the other hand, if the needle throttle valve 13 is fully closed, the deceleration will start from the position B where the cushion starts, as shown by the curve γ, and will stop over time t ₂ ″−t _1. However, this takes time. Too much,
Moreover, it is not preferable because the cushion suddenly decelerates from the point where it starts to take off and a shock is generated. Therefore, when the needle throttle valve 13 is fixed at a predetermined position, the curve β
As shown in , smooth deceleration can be performed, and smooth operation can be obtained at any time when the cushion ring 6 enters, during deceleration, and when it stops, which is advantageous for the driven body. Moreover, since the operating time is limited to the minimum necessary t ₂ - t ₁ , it is advantageous in terms of cycle time. Knowing the cushion stroke length Sc and the operating time t _c = t ₂ - t ₁ from Fig. 5a. I can do it.

Next, FIG. 5b shows a velocity diagram. This diagram is a v-t diagram showing temporal changes in velocity corresponding to curves α, β, and γ shown in FIG. The piston speed and the deceleration speed after entering the cushion ring 6 are clarified. Here again, the curve β shows deceleration and stopping without impact and in the minimum necessary time.

Further, FIG. 5c shows an acceleration diagram. This diagram is an a-t diagram showing the temporal change in acceleration corresponding to the curve α, the curve β, and the curve γ shown in FIGS. The shock intensity when the cushion is activated is directly expressed. That is, the curve α shows a rapid change, and the curve γ shows a maximum acceleration -a when the cushion ring 6 enters, and then gradually decreases. On the other hand, the curve β shows a relatively small constant acceleration from time _t1 to time _t2 , indicating that the impact is small.

As explained above, by adjusting the needle throttle valve 13, the operating characteristics near the stroke end of the hydraulic cylinder 1 can be changed in various ways. Was. Further, although the explanation has been given using an example of a hydraulic cylinder, the same applies to a pneumatic cylinder.

[Problems to be solved by the invention] However, there is a problem in that it is impossible to accurately reproduce the adjustment results of the cushion function of a hydraulic cylinder in other hydraulic cylinders simply by visually checking them by an operator. Moreover, it was also impossible to quantitatively evaluate the cushion function.

In addition, in experiments in laboratories, etc., it is also possible to attach a potentiometer or the like directly or indirectly to a hydraulic cylinder and record the electrical signal on an electromagnetic oscilloscope for analysis, or to use an accelerometer directly on the hydraulic cylinder. By attaching and measuring the hydraulic cylinder, it is possible to understand the cushion operation status of the hydraulic cylinder, but these methods are not suitable for on-site work and are not suitable for operation by workers. The point was hot.

[Purpose of the invention] The present invention was made in order to solve the above problems, and it is possible to quantitatively and quantitatively adjust the cushions of fluid pressure cylinders, which are used in large quantities in various machines, without relying on intuition. It is an object of the present invention to provide a lightweight and portable measuring device for measuring cushion characteristics of a fluid pressure cylinder, which allows adjustment results to be easily and quickly performed and to directly read adjustment results on the spot.

[Means for Solving the Problems] The device for measuring cushion characteristics of a fluid pressure cylinder according to the present invention receives a cushion ring provided on a piston that operates a rod into a chamber provided at an end of the cylinder. It is applied to a fluid pressure cylinder that absorbs a shock at the end of a stroke and discharges fluid between the piston and the end of the cylinder to the outside of the cylinder via an adjusting means, a detection means for detecting the amount of movement of the fluid pressure cylinder at the stroke end, the detection means comprising a movement amount detector that contacts the tip of the rod of the fluid pressure cylinder and follows the movement of the rod at the end of the stroke; and the detection means A process of analyzing the movement amount signal at the stroke end of the fluid pressure cylinder input from the detection means connected to the sensor and calculating the position, velocity, and acceleration of the fluid pressure cylinder at the stroke end as relative relationships with the time axis. and display means for outputting and displaying the cushion characteristics which are the calculation results of the processing means.

[Operation] In the above-described configuration, in order to grasp the cushion operation status of the fluid pressure cylinder, when the fluid pressure cylinder cushion characteristic measuring instrument according to the present invention is set and the fluid pressure cylinder is operated to the stroke end, the fluid pressure is The amount of movement of the piston rod of the cylinder is detected by the detection means and input to the processing means. The processing means analyzes the input movement amount of the piston rod of the fluid pressure cylinder, and calculates the position, velocity, and acceleration of the piston rod of the cylinder as a relative relationship with the time axis. The calculation result of the processing means is input to the display means, and the display means outputs and displays the calculation result.

[Example] The present invention will be explained below with reference to an example shown in FIGS. 1 and 2.

As shown in FIG. 1, a hydraulic cylinder under test 21 (hereinafter referred to as hydraulic cylinder 2
Call it 1. ) is the mounting bracket 23 for the base 22.
The rod 24 is fixed by bolts or the like through the rod 24, and is connected to a hydraulic pressure generating device and a control device (not shown) to drive the rod 24 back and forth.

A detection means 25 is provided on the side of the hydraulic cylinder 21.
A mounting bracket 27 is provided on the support 26 of the detection means 25, and the detection means 25 can be mounted on a base 29 using a mounting device 28, such as a magnetic stand, which can freely fix the mounting posture and position. is installed on top of. The detection means 25
A movement detecting body 31 (hereinafter referred to as the detecting body 31) is supported on the support body 26 so as to be slidable back and forth via an elastic member 30 such as a compression spring.
The tip 31a of the detection body 31 is brought into pressure contact with the tip end surface 24a of the rod 24 of the hydraulic cylinder 21 with its axis aligned.

Here, for example, when the hydraulic cylinder 21 moves forward, let C be the forward end position, B be the position where the cushion is released, and A be the position in the middle of forward movement.
The cushion stroke is the distance between position B and position C, and the detection body 31 comes into contact with the tip end surface 24a of the rod 24 from position A, and even if the rod 24 moves forward to position C, there is a margin in the stroke. It is arranged in such a way that there is a

The support body 26 is equipped with a known potentiometer that can continuously convert the amount of movement of the detection body 31 into, for example, a voltage change amount, and a cable 32 for transmitting the voltage change amount is led out from the potentiometer. A/
It is connected via a D converter 34.

The processing means 33 can be configured compactly using, for example, a microcomputer, and as shown in FIG. CPU 35 is the central part of means 33
is connected to via an input/output circuit (not shown). The CPU 35 is connected to a data memory 36 and a program memory 37, and is also connected to a clock 38.
It is configured to receive a clock pulse signal from 8 and perform calculations and processing of input data according to a program. An operation signal input device 40 and a data input device 41 are connected to the CPU 35 via an interface 39.

Next, the processing means 33 has an interface 3.
9, a printer 43 as a display means 42 and a display device 44 are connected to display the results of calculations and processing by the processing means 33.

Next, the operation of the configuration described above will be explained.

First, a data reading command is given to the processing means 33 by the operation signal input device 40, and the hydraulic cylinder 21 is driven to advance the rod 24 from position A to forward end position C. Since the detection body 31 of the detection means 25 is operated in accordance with the operating state of the rod 24, the amount of movement of the rod 24 is continuously converted into a voltage change amount by the potentiometer of the detection means 25. .

The amount of voltage change is transmitted through the cable 32, converted into a digital signal by the A/D converter 34, and input to the processing means 33.

Therefore, the CPU 35 of the processing means 33 operates at a fixed period of time (for example,
The movement amount data of the rod 24 inputted from the A/D converter 34 is stored in the data memory 36 in accordance with the pulse signal (100 msec). When the end signal is input from the operation signal input device 40, the CPU
35 finishes reading the data, and analyzes the movement amount data per unit time stored in the data memory 36 according to the processing procedure pre-installed in the program memory 37, and determines the position and speed of the rod 24. and acceleration are each calculated as a function of time t.

The calculation results by the processing means 33 are transmitted to the printer 43 via the interface 39, and the printer 43 prints the calculation results as an s-t diagram, a v-t diagram, and an a-t diagram. Display the output.

Further, by using the data input device 41, an appropriate value of the cushion operation characteristic is inputted and stored in the data memory 36 of the processing means 33 in advance, for example, as an acceleration diagram such that the maximum acceleration is suppressed within a predetermined value. By comparing and calculating the result of actual measurement and analysis, it is possible to inform the measurer whether the measurement result is appropriate or not by displaying an output on the display device 44 using, for example, color-coded lamps.

In the embodiments described above, a hydraulic cylinder was taken up, but it goes without saying that the present invention can be similarly applied to measuring the characteristics of a pneumatic cylinder.

[Effects of the invention] As explained above, according to the invention, the amount of movement of the rod at the stroke end of the fluid pressure cylinder is detected by the detection means, and the signal of the amount of movement is input to the processing means. Since the system is configured to carry out arithmetic processing and output and display the result of the calculation by the display means, there is an effect that the cushion operating state of the fluid pressure cylinder can be automatically measured quantitatively and quickly. Furthermore, as mentioned above, the present invention has a compact structure including the display means, and uses special jigs etc. even though it is constructed completely separate from the fluid pressure cylinder that is the object to be measured. It is possible to carry out measurements by equipping the cylinder without having to do so.
Therefore, even if the fluid pressure cylinder is still assembled in the device, measurements can be made simply by bringing this measuring device to the site and touching the displacement detector to the tip of the rod of the fluid pressure cylinder. You can check the measurement results on the spot.

Therefore, according to the present invention, the cushion adjustment of the fluid pressure cylinder can be carried out quantitatively without relying on the intuition of the worker, so it is possible to realize highly reproducible cushion operating conditions. In addition, there is an effect that the quality of the fluid pressure cylinder can be stabilized and the quality of the device using the fluid pressure cylinder can be stabilized.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram showing an embodiment of the present invention, Fig. 2 is a control block diagram of the embodiment, Fig. 3 is a partially omitted cross-sectional view of a hydraulic cylinder, and Fig. 4 is:
Enlarged views of the parts in FIG. 3, FIGS. 5 a to c,
These are diagrams representing characteristics of a fluid pressure cylinder during cushion operation, including a position-time diagram (s-t diagram), a velocity-time diagram (v-t diagram), and a velocity-time diagram (v-t diagram), respectively.
It is an acceleration-time diagram (at diagram). 21... Hydraulic cylinder to be tested as a fluid pressure cylinder (hydraulic cylinder), 24... Rod, 2
5...detection means, 31...detection object, 33...processing means, 42...display means, 43...printer.

Claims (1)

[Claims for Utility Model Registration] A cushion ring provided on the piston that operates the rod is received in a chamber provided at the end of the cylinder to absorb the impact at the end of the stroke, and Applicable to a hydraulic cylinder in which the fluid between the rod and the end is discharged out of the cylinder through an adjusting means, and the rod is moved at the end of its stroke while in contact with the tip of the rod of the hydraulic cylinder. a detection means for detecting the amount of movement of the fluid pressure cylinder at the end of its stroke, which is equipped with a movement amount detector to follow; and a signal of the amount of movement of the fluid pressure cylinder at the end of its stroke connected to the detection means and input from the detection means. processing means for analyzing and calculating the position, velocity, and acceleration of the fluid pressure cylinder at the stroke end as relative relationships with respect to the time axis; and display means for outputting and displaying the cushion characteristics that are the calculation results of the processing means; An instrument for measuring cushion characteristics of a fluid pressure cylinder, comprising: