JPH0450997Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a knockout device disposed in the bed of a press machine.

[Conventional technology]

2, 3 and 4 show conventional knockout devices.

A rotary shaft 2 is rotatably disposed at the bottom of a bed 1 of the press machine with bearings 3, 4, and 5, and levers 6 and 7 are fixed to the rotary shaft 2. As shown in FIG. 3, the lower end of a drive rod 8 is connected to the tip of the lever 6, and the upper end of the drive rod 8 is connected to one end of a lever 10 which is rotatable about a shaft 9. A roller 11, which is a cam follower, is provided at the other end of the lever 10. This roller 11 comes into contact with a cam 14 fixed to a crankshaft 13 that moves a slide 12 (see Fig. 2) of the press machine up and down, and a pressing force from an air cylinder 15 is constantly acting on the lever 6. , the roller 11 is the cam 14
Always in contact with.

The lever 7 is provided with a roller 16 as shown in FIG. 4, and a knockout pin 17 is attached to the roller 16.
The bottom ends of the two are in contact with each other. As shown in FIG. 2, the knockout pin 17 is inserted vertically into the interior of the bed 1, and is guided by a guide member 18 so as to be able to move up and down.

From the above structure, when the crankshaft 13 rotates,
Since the knockout pin 17 moves up and down due to the vertical movement of the drive rod 8 and the rotation of the rotating shaft 2, the mechanism from the roller 11 to the roller 16 allows
A knockout pin pushing mechanism 19 is configured to push up the knockout pin 17 in synchronization with the rotation of the crankshaft 13.

As shown in FIG.
2 is attached, and a counter punch 23 vertically opposed to the knockout pin 17 is arranged inside the die holder 21 so as to be vertically movable.

The slide 12 is lowered by the rotation of the crankshaft 13, and the slug 25 set in the die 22 is forged by the punch 24 attached to the slide 12, and then the knockout pin is pushed up by further rotation of the crankshaft 13. The knockout pin 17 is pushed up by the mechanism 19,
When the counter punch 23 is raised by the knockout pin 17, a molded product 26 formed from the slug 25 is ejected from the die 22.

[The problem that the idea aims to solve]

FIG. 5 shows the vertical motion A of the slide 12 and the vertical motion B of the knockout pin 17, which have been described above. This B is an ideal, not an actual one. B' in FIG. 6 shows the actual vertical movement of the knockout pin 17. C, D, and E shown in Figures 5 and 6 are the second
This is shown in the figure, and C shows the molded product 26 placed in the die 2.
2, D is the counter punch escape gap provided between the molded product 26 and the counter punch 23, and E is the knock out stroke required to protrude from the counter punch 23. This is a gap for knockout pin escape.

Since the molded product 26 is strongly attached to the die 22 due to the molding load from the punch 24, the knockout pin 17 is pushed up by the knockout pin push-up mechanism 19.
The molded product 26 does not separate from the die 22 immediately after being pushed up by E+D, and is not ejected. In other words, even though a knockout force is applied from the crankshaft 13 to the knockout pin 17 and further to the counter punch 23 via the knockout pin push-up mechanism 19, the molded product 26 does not begin to eject. Out pin push up mechanism 19, knock out pin 1
7. Strain energy is accumulated in the counter punch 23.

Here, if the strain energy is E _S , the amount of strain is δ, and the knockout force is F, then E _S =Fδ/2.

On the other hand, when the strain energy is sufficiently accumulated, the molded product 26 is ejected from the die 22 by this energy, and the strain energy becomes kinetic energy.

Here, the kinetic energy is E _K , the total weight of the knockout pin push-up mechanism 19, the knockout pin 17, and the counter punch 23 is W, the speed of movement when strain energy is released as kinetic energy is V ₂ , and gravity is If the speed is g, then E _K = Wv ₂ ² /2g E _S and E _X are equal, so v ₂ is also the rising speed of the knockout pin 17 when ejecting the molded product 26 from the die 22, and this v ₂ is the rising speed of the knockout pin 17 when no strain energy is accumulated v ₁ (6th
(see figure) is 2 to 5 times larger.

Since the molded product 26 is ejected from the die 22 by the knockout pin 17 rising at such a high speed, the molded product 26 jumps up greatly and flies out of the die 22. This may not cause any problems if the molded product 26 is molded using a so-called single-shot press machine, but a transfer press that automatically transports the molded product to each processing stage using a conveying device such as a feed bar and sequentially molds the molded product If a machine is used, a problem arises in that automatic conveyance of the molded product is impossible.

The purpose of this invention is to provide a press that can prevent the molded product from flying out from the die, and therefore, when the molded product is automatically transported using a conveying device and molded into a molded product, this automatic transport can be carried out reliably. The company provides mechanical knock-out devices.

[Means to solve the problem]

For this reason, the knockout device for a press machine according to the present invention has a knockout pin pushing mechanism that is driven by the crankshaft of the press machine and pushes up a knockout pin disposed on the bed. In a knockout device of a press machine that ejects a molded product from a die by an elevated counter punch, a hydraulic cylinder is provided in the middle of the molded product ejecting force transmission path from the knockout pin pushing up mechanism to the counter punch, through which the molded product ejecting force acts on the piston. and communicating two oil chambers partitioned by the piston in the hydraulic cylinder with an oil passage,
This oil passage is characterized in that an orifice is provided in the oil passage to restrict the amount of oil flowing when the knockout pin is raised.

[Effect]

Because the molded product is strongly attached to the die, the knockout pin push-up mechanism, knockout pin,
Distortion energy is accumulated in the counter punch, etc., and when this distortion energy becomes kinetic energy and is released and the knockout pin, etc. tries to rise, the piston of the hydraulic cylinder also moves from one oil chamber in the hydraulic cylinder to the other. Oil flows into the oil chamber of the die, and the oil flow rate at this time is restricted by an orifice, so the movement speed of the piston is suppressed, and as a result, the rising speed of the knockout pin is also suppressed, preventing the molded product from flying out from the die. It can be prevented.

〔Example〕

FIG. 1 shows an apparatus according to an embodiment of the present invention. In the following description, the same members or members having the same functions as those of the conventional device already described are given the same reference numerals, and the description thereof will be simplified or omitted.

A hydraulic cylinder 30 is provided inside the bed 1 of the press machine, and a piston rod 32 of a piston 31 of this hydraulic cylinder 30 is connected to the hydraulic cylinder 30.
It penetrates up and down and moves up and down. piston rod 3
A knockout pin 17 is arranged on the upper side of 2,
Further, the lower end of the piston rod 32 comes into contact with the roller 16 of the lever 7 that constitutes the knockout pin push-up mechanism 19.

For this reason, the knockout pin push-up mechanism 19
This means that the hydraulic cylinder 30 is disposed in the middle of the molded product ejection force transmission path 33 that is constituted by each component from the to the counter punch 23,
A force for ejecting the molded product acts on the piston 31 .

Inside the hydraulic cylinder 30 is a piston 31 that connects the upper oil chamber 3.
4 and a lower oil chamber 35, and these upper oil chambers 3
4. The lower oil chamber 35 is communicated with an oil passage 36. An orifice 38 with a check valve 37 is provided in the oil passage 36, and this orifice 38 is a variable orifice. The check valve 37 closes when oil flows from the upper oil chamber 34 to the lower oil chamber 35, but opens when oil flows from the lower oil chamber 35 to the upper oil chamber 34.
A pump 39 is connected to the oil passage 36, and the pump 39 fills the upper oil chamber 34 and the lower oil chamber 35 with oil from a tank 40 through a check valve 41.

Next, we will discuss the effect.

The rotation of the crankshaft 13 starts driving the knockout pin pushing up mechanism 19, and when the lever 7 swings upward due to the rotation of the rotation shaft 2, the piston rod 32 pushes up the knockout pin 17 and the counter punch 23. At this time, the oil in the upper oil chamber 34 is caused by the piston 31 to flow into the lower oil chamber 35 through the orifice 38, but the upward stroke of the knockout pin 17 is E+ as shown in FIG.
Since the rising speed of the piston rod 32 up to the stroke corresponding to D is a slow speed corresponding to v ₁ , the oil flows into the lower oil chamber 35 without being subjected to the throttling action of the orifice 38, and the piston rod 32 and the knockout pin 17. Counter punch 2
3 rises at a predetermined speed.

When the upward stroke of the knockout pin 17 reaches a stroke corresponding to E+D, the upper end of the counter punch 23 comes into contact with the molded product 26. Since the molded product 26 is strongly attached to the die 22, the knockout pin push-up mechanism 19, the piston rod 32, the knockout pin 17, and the counter punch 2
3 stores strain energy due to the molded product ejection force transmitted from the crankshaft 13. When this strain energy becomes sufficiently large, the counter punch 23 pushes the molded product 26 out of the die 22, and the strain energy is converted into kinetic energy.

This kinetic energy causes the piston rod 32,
The knockout pin 17 and counter punch 23 try to rise at a high speed, but the amount of oil flowing from the upper oil chamber 34 to the lower oil chamber 35 by the piston 31 is throttled by the orifice 38, so the piston rod 32 and the knockout pin 17. Counter punch 2
3 is prevented from rising at a high velocity corresponding to the velocity of v ₂ shown in FIG.

For this reason, the molded product 26 is ejected without the molded product 26 jumping out from the die 22, and when molded by automatically transporting the molded product 26 to each processing stage in order using a conveying device such as a feed bar of a transfer press machine. , molded product 2 by this conveyance device
6 can be reliably carried out automatically.

Since the oil pressure in the hydraulic cylinder 30 and orifice 38 changes in proportion to the square of the speed of the piston rod 32, when the strain energy is large, that is, when the adhesion force of the molded product 26 to the die 22 is large, the strain energy becomes kinetic energy. When the piston rod 32 etc. tries to rise at a high speed, the rise of the piston rod 32 is suppressed by pressure proportional to the square of the speed. Therefore, the greater the strain energy, the more effective the ejection speed of the molded product 26 becomes. Can be made smaller.

When the ejection of the molded product 26 is finished and the piston rod 32 etc. descend, the oil in the lower oil chamber 35 returns to the upper oil chamber 34 through the open check valve 37, so the piston rod 32 etc. cannot return downward. done quickly.

In the above, the ejection speed of the molded product 26 when the strain energy is converted into kinetic energy is determined by the total weight of the knockout pin push-up mechanism 19, the piston rod 32, the knockout pin 17, the counter punch 23, the drawing amount of the orifice 38, etc. However, since the actual ejection speed is the addition of the frictional force between each component, it is not possible to determine the exact ejection speed. Therefore, in this embodiment, the orifice 38 is a variable orifice as described above, and the molded product 26
In the preparatory stage before starting the forming operation, a trial operation was performed in which the amount of drawing of the orifice 38 was changed in stages, and the amount of drawing of the orifice 38 that would obtain the appropriate ejection speed was determined, and the orifice was adjusted to the optimum drawing amount. 38 is fixed so that the molding operation of the molded product 26 can be performed.

In the above embodiment, the hydraulic cylinder 30 is used to push the knockout pin up mechanism 19 and the knockout pin 1.
7, but the hydraulic cylinder 30
The knockout pin 17 may be arranged between the knockout pin 17 and the counter punch 23, or the knockout pin 17 may be divided into two vertically divided parts, and the hydraulic cylinder 30 may be arranged between them. That is, the hydraulic cylinder 30 may be disposed anywhere in the molded product ejection force transmission path 33 from the knockout pin push-up mechanism 19 to the counter punch 23.

Further, the knockout pin pushing up mechanism 19 is not limited to the one in the above embodiment, and any mechanism can be used as long as it is driven by the crankshaft of the press machine and pushes up the knockout pin, etc. good.

[Effect of idea]

According to the present invention, it is possible to prevent the molded product from flying out from the die. Therefore, when the molded product is automatically transported by the transfer press machine conveyor and molded at each processing stage, this automatic transport You will be able to do this reliably.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a device according to an embodiment of the present invention, FIG. 2 is a view similar to FIG. 1 showing a conventional device,
Figure 3 is a side view showing the knockout pin push-up mechanism to which driving force is transmitted from the crankshaft of the press machine, Figure 4 is a sectional view taken along the - line in Figure 2, and Figure 5 shows the vertical movement of the slide and the knockout pin pushing mechanism. Diagram 6 showing the ideal vertical motion of the out pin.
The figure shows the actual vertical movement of the knockout pin, and also shows the problems of the conventional device. 1...Bed, 12...Slide, 13...Crankshaft, 15...Air cylinder, 17...Knockout pin, 19...Knockout pin pushing up mechanism, 22...Dice, 23...Counter punch, 24 ...Punch, 25...Slag, 26...
Molded product, 30... Hydraulic cylinder, 31... Piston, 32... Piston rod, 33... Molded product ejection force transmission path, 34, 35... Oil chamber, 36...
...Oil passage, 37...Check valve, 38...Orifice.

Claims (1)

[Scope of utility model registration request] The press machine has a knock-out pin pushing mechanism that is driven by the crankshaft of the press machine and pushes up a knock-out pin placed on the bed, and the molded product is ejected from the die by a counter punch that is raised by the push-up of the knock-out pin. In the knockout device, a hydraulic cylinder is provided in the middle of the molded product ejection force transmission path from the knockout pin push-up mechanism to the counter punch, and the molded product ejecting force acts on the piston. The two oil chambers are communicated by an oil passage, and a variable orifice is provided in this oil passage to restrict the oil flow rate when the knockout pin suddenly rises when ejecting the molded product attached to the die. Features a knock-out device for press machines.