JPH03151199A - Overloading prevent device for two point press - Google Patents

Abstract

PURPOSE:To diminish the change of the mechanical deformation of an overloading prevent unit by providing a tuning valve which connects with supply ports of both control valves and, when the hydraulic pressure in a cylinder room of one of overloading prevent units is released, releases the hydraulic pressure in the cylinder room of the other overloading prevent unit. CONSTITUTION:The control valves 20A, 20B having a supply port 22, a lubricator 23, a waste oil port 24, a main valve 26, an auxiliary valve 27, a breaking pressure setting mechanism 28 each are provided in overlapping prevent units 10A, 10B. Breaking pressure setting means 50A, 50B possible to set the open pressures of the main valves 26 are provided. The lubricators 23 of each control valve 20A, 20B are communicated with each other to connect with a hydraulic supply device 60. The supply ports 22 of both control valves 20A, 20B are connected with each other and when the hydraulic pressure in the cylinder room 5 of one of the overloading prevent units 10A is released, the tuning valve 70 is provided to release the hydraulic pressure in the cylinder room 5 of the other overloading prevent unit 10B. Thus, the slide can be prevented from inclining.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an overload prevention device for a two-point press. In detail, in a two-point press in which the slide is supported on the crankshaft via two sets of metal-sealed overload prevention units, the oil pressure in the cylinder chambers of both overload prevention units is kept constant and the same setting oil pressure, and each unit is The present invention relates to an overload prevention device for a two-point press that can set a breaking load (a press load when a metal seal portion that seals a cylinder chamber breaks).

[Prior Art] In a press, an overload prevention device is provided between a connecting rod connected to a crankshaft and a slide.

Therefore, a conventional overload prevention device will be explained with reference to FIGS. 5 and 6. First, as shown in FIG. 5, a metal seal part 4 is formed between a piston 2 connected to a point part 1 and a cylinder 3 into which it is fitted, and a set hydraulic pressure ( For example, Ps in FIG. 6 is established. At this time, the piston 2 and cylinder 3 undergo mechanical deformation in accordance with the set oil pressure of the cylinder chamber 5.

Here, as shown in FIG. 6, when the press load increases, the oil in the cylinder chamber 5 is compressed, and the oil pressure in the cylinder chamber 5 increases from Ps. When the press load becomes Lb, the oil pressure in the cylinder chamber 5 becomes pb, and the metal seal portion 4 is opened, that is, broken. As a result, the oil in the cylinder chamber 5 is released to the tank 8 through the oil drain system 7. Therefore,
Relative movement between the piston 2 and the cylinder 3 is allowed, and overload that would cause damage to the mold or the like is prevented.

In a two-point press, since there are two connection points between the crankshaft and the slide, the above-mentioned piston 2 and cylinder 3 are provided at each point. in this case,
A common pump 6 is used to establish the same set oil pressure in the cylinder chamber 5 of each cylinder 3.

[Problems to be Solved by the Invention] However, the above-described conventional overload prevention device has the following problems.

Now, as shown in FIG. 6, if the press load when the metal seal part 4 breaks is Lb, and the oil pressure in the cylinder chamber 5, that is, the breaking oil pressure, is pb, then the set oil pressure with respect to the breaking oil pressure pb is equal to the press load. The PS becomes lower by the amount ΔP of the increase in the oil pressure in the cylinder chamber 5 due to the increase. Therefore, when the breaking load is set to L b 1, for example, depending on the mold used, that is, when the breaking oil pressure is set to a low pressure, it is necessary to change the set oil pressure to Ps.

However, when the set oil pressure is changed, the mechanical deformation of the cylinder 3 and the piston 2 (particularly the ball cup portion) changes, so there is a problem that the bottom dead center position of the slide changes. Furthermore, since the gap between the point portions 1 also changes, processing accuracy deteriorates and smooth operation of the press becomes difficult. This leads to a shortened lifespan of molds and presses. For this reason, the set oil pressure cannot be made very low, and the range of application is narrow.

In particular, in the case of a two-point press, there is a demand for setting the breaking load, that is, the breaking oil pressure, to a different value at each point due to demands for diversification.

However, to set a different breaking oil pressure at each point,
After separating the hydraulic system paths at each point, it is necessary to set different oil pressures at each point, resulting in differences in the amount of mechanical deformation between the cylinder 3 and piston 2 and the gap between point 1 at both points. As a result, there is a problem that the slide tilts.

Furthermore, if the hydraulic system path is separated at each point, there arises a problem that when one of the two points breaks, the hydraulic pressure at the other point is not released, resulting in the slide tilting.

The purpose of the present invention was to solve such conventional problems, and it is possible to expand the range of application and minimize changes in mechanical deformation, and to To provide an overload prevention device for a two-point press that can set the breaking hydraulic pressure and synchronize the other point when either one of the two points breaks.

[Means for Solving the Problems] Therefore, in the present invention, both points are set to the same and constant oil pressure, and the breaking load, that is, the breaking oil pressure can be set independently at each point.
The structure is such that when either one breaks, the other can also be synchronized.

Specifically, in an overload prevention device for a two-point press in which a slide is supported on a crankshaft via two sets of metal seal type overload prevention units, a supply port connected to a cylinder chamber of the overload prevention unit and a , an oil supply port, an oil drain port that communicates with the supply port, a main valve that opens and closes communication between the supply port and the oil drain port, and a main valve that opens and closes communication between the supply port and the oil drain port, and when the main valve is closed, the oil supply Each of the overload prevention units is provided with a control valve having a sub-valve that communicates with the port and a rupture pressure setting mechanism that sets the opening pressure of the main valve, and the rupture pressure setting mechanism of each control valve is provided with a A rupture setting means is provided which is connected to each other and can independently set the opening pressure of the main valve, and the oil supply ports of each of the control valves are connected to a hydraulic pressure supply device by communicating with each other. The present invention is characterized in that a synchronized valve is connected between the supply ports and releases the hydraulic pressure in the cylinder chamber of the other overload prevention unit when the hydraulic pressure in the cylinder chamber of one of the overload prevention units is released.

[Function] The hydraulic supply device supplies hydraulic pressure to the oil supply port of the control valve.
Supply oil into the cylinder chambers of each overload prevention unit through the sub-valve and supply port, and establish the same set hydraulic pressure in the cylinder chambers of both overload prevention units. Compression room a! The opening pressure of the main valve at R is set independently.

Therefore, when the press load applied to each overload prevention unit increases, the oil pressure in the cylinder chamber of each overload prevention unit starts to rise from the set oil pressure. Eventually, when the oil pressure in the cylinder chamber reaches the opening pressure of the main valve set at the top of each rupture pressing chamber, the main valve is opened. Then, since the supply port is communicated with the oil drain port, the hydraulic pressure in the cylinder chamber of the overload prevention unit is released from the oil drain port through the supply port. As a result, when the oil pressure in the cylinder chamber decreases, the metal seal portion breaks, thereby preventing overload.

At this time, if either one of the two overload prevention units breaks, the synchronization valve also releases the hydraulic pressure in the cylinder chamber of the other overload prevention unit, that is, the metal seal part breaks, so they can be synchronized with each other.

Therefore, the breaking load, that is, the breaking oil pressure can be set independently for each overload prevention unit while keeping the oil pressure in the cylinder chamber of the double feed load prevention unit at a constant set oil pressure. This has the advantage that the breaking pressure can be set to a low pressure without changing the set oil pressure, so the range of application can be expanded, and changes in mechanical deformation of the overload prevention unit can be minimized. Further, since the hydraulic pressure setting for both feeding load prevention units can be the same and the breaking hydraulic pressures can be set separately, it is possible to meet the demand for diversification without causing the slide to tilt. Furthermore, when either one of the two feeding load prevention units breaks, the other can also be synchronized.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

FIG. 1 shows the overload prevention device of this embodiment. The overload prevention device consists of two metal seal overload prevention units IOA and IOB installed at the connection point between the crankshaft and the slide, and each overload prevention unit IOA.
, control valves 20A each connected to IOB,
20B, and pressure regulating valves 50A, 50 as rupture setting means connected to each control valve 2OA, 20B.
B, a hydraulic pressure supply device 60 that supplies hydraulic pressure to both the control valves 2OA and 20B, and the overload prevention unit I.
It is comprised of a synchronized valve 70 that releases the hydraulic pressure in the other cylinder chamber 5 when the hydraulic pressure in either one of the cylinder chambers 5, OA or IOH, is released. The overload prevention units 10A and 10B have the same structure as shown in FIG. 4, so the same reference numerals are given and the explanation thereof will be omitted.

Therefore, first, additional details of each control valve 20A, 20B will be explained with reference to FIG. In the same figure, the valve body 21 is formed with a supply port 22, an oil supply port 23, an oil drain port 24, and a pressurized air inlet port 25, and the supply port 22 and the oil drain port 24 communicate with each other. A main valve 26 that opens and closes, a sub-valve 27 that communicates the oil supply port 23 and the supply port 22 when the main valve 26 is closed, a breakability setting R horizontal 28 that sets the opening pressure of the main valve 26, and An accumulator 29 is provided respectively.

The supply port 22 is connected to the oil drain port 24 via the main valve seat 31.
is communicated with. By moving the main valve 26 toward and away from the main valve seat 31, communication between the supply port 22 and the oil drain port 24 is opened and closed.

The said fracture compression chamber I! The side 28 is the pressurized air inlet 25
a cylinder chamber 32 formed in communication with the cylinder chamber 32; a piston 33 that is slidably housed in the cylinder chamber 32 and has the main valve 26; 33 and a spring 34 that urges the spring 33. A protrusion 36 is integrally formed at the center of one end surface of the piston 33 and is slidably fitted into a communication passage 35 that communicates the cylinder chamber 32 and the oil filler port 23 . Here, the diameter of the communication passage 35 and the main valve seat 31
are formed to have the same diameter.

A communication passage 38 is formed in the central axis direction of the main valve 26 and the piston 33 to communicate the oil supply port 23 and the supply port 22 and has a sub-valve seat 37 in the middle.

The auxiliary valve 27 that moves toward and away from the auxiliary valve seat 37 is slidably inserted into the communication passage 38, and the auxiliary valve 27 is inserted from the supply port 221111 toward the oil filler port 23 side. A spring 39 is inserted that urges the sub-valve seat 37 in the direction of contact. The sub-valve 27 is formed with a communication passage 40 that communicates the oil supply port 23 and the supply port 22 when the sub-valve 27 is separated from the sub-valve seat 37.

The accumulator 29 has a cylinder chamber 41 and is slidably housed in the cylinder chamber 41 and connected to the communication path 3.
5, and a spring 44 that urges the piston 43 in a direction in which the protrusion 42 enters the communication passage 35.

The cylinder chamber 41 is formed with a pressurized air introduction port 45 and an open port 46 that communicates with the atmosphere.

Here, the connection of the control valves 2OA and 20B on each day will be explained. The supply port 22 of each control valve 20A, 20B is connected to the corresponding overload prevention unit IO.
A, connected to the cylinder chamber 5 of IOB. Further, the oil supply ports 23 are connected to each other and then connected to the hydraulic pressure supply device 60. Hydraulic supply system! 60 is composed of a pump 6, a tank 8, a check valve 9, and the like.

Further, the oil drain ports 24 are both connected to the oil drain system 7. Further, the pressurized air inlet 25 is connected to the pressurized air source 51 after being connected to each other via the corresponding pressure regulating valves 50A and 50B. Further, the pressurized air inlets 45 are connected to each other and then to a pressurized air source 51 via a pressure regulating valve 52. Here, the operating pressurized air pressure of the pump 6 is used by making the diameter ratio of the piston 43 and the protrusion 42 the same as the diameter ratio of the pump 6.

Next, the detailed structure of the tuning valve 70 will be explained with reference to FIG.

In the figure, the valve body 71 includes each of the control valves 2
Two oil supply lowers 2A, 72B connected to the supply ports 22 of the OA, 20B and two oil drain lowers 3A, 73B connected to the oil drainage system 7 are formed, and one oil supply lower 2A is connected to the other. Oil supply lower 2B and oil drain lower 3A
A communication passage 74A that communicates with the oil supply lower 2A and a communication passage 74B that communicates the other oil supply lower 2B with one of the oil supply lower 2A and the oil discharge lower 3B are formed.

In each of the communication passages 74A and 74B, there is a valve seat 75A in the middle.
, 75B, and a spring 76A.
, 76B biased in mutually opposite directions.
A, 78A, 77B, and 78B are inserted.

The valve bodies 77A and 78A are connected to the double feed load prevention unit IO.
A. When the IOB is not broken, it is pressed against the valve seat 75A by the oil pressure supplied to the oil supply lower 2B, thereby sealing the oil pressure supplied to the oil supply lower 2A. When the overload prevention unit IOB breaks, that is, when the oil pressure supplied to the oil supply lower 2B drops to a predetermined pressure, it is separated from the valve seat 75A by the oil pressure of the oil supply lower 2A, and the oil supply lower 2A is communicated with the oil drain lower 3A. As a result, the hydraulic pressure in the cylinder chamber 5 of the overload prevention unit IOA is released.

The valve bodies 77B and 78B are connected to both the overload prevention units IO.
A. When the IOB is not broken, it is pressed against the valve seat 75B by the oil pressure supplied to the oil supply lower 2A, and seals the oil pressure supplied to the oil supply lower 2B. When the overload prevention unit IOA breaks, that is, when the oil pressure supplied to the oil supply lower 2A drops to a predetermined pressure, the oil pressure of the oil supply lower 2B separates it from the valve seat 75B, thereby communicating the oil supply lower 2B with the oil drain port 73B. As a result, the hydraulic pressure in the cylinder chamber 5 of one overload prevention unit IOB is released.

Next, the operation of this embodiment will be explained.

First, the pump 6 is activated, and the oil in the tank 8 is pumped through the oil filler ports 23 of both control valves 2OA and 20B, and the communication passages 35 and 3.
8.40, both overload protection units I via the supply port 22
It is supplied to the cylinder chambers 5 of OA and IOB, and the oil pressures in both cylinder chambers 5 are set to the same set oil pressure Ps. At this time, since the communication passage 35 and the main valve seat 31 have the same diameter, they are balanced at the set oil pressure Ps.

Now, as shown in FIG. 4, when a press load of Lb is applied while the oil pressure in the cylinder chamber 5 is at the set oil pressure Ps, the oil pressure in the cylinder chamber 5 increases by ΔP and becomes P b +. Therefore, when the pressure is increased by this ΔP'', that is, when the oil pressure in the cylinder chamber 5 reaches the breaking oil pressure Pb1, the control valve 2OA is opened so that the main valve seat 31 opens, that is, the piston 33 descends. , 20B breakability setting Wi The pressurized air pressure in the cylinder chamber 32 of the oval 28 is set by the pressure regulating valves 50A and 50B. In this case, the pressure in the cylinder chamber 32 next to the rupture pressure setting machine 28 of both control valves 20A, 20B can be set separately.

Therefore, when the press operation is performed, the oil pressure in the cylinder chamber 5 increases as the press load increases. However, within the normal operating range, the oil pressure in the cylinder chamber 5 is the breaking oil pressure Pb1.
The main valve seat 31 is never opened.

However, when the press load increases due to the biting of the mold, etc., and the oil pressure in the cylinder chamber 5 reaches the breaking oil pressure Pb, for example, the oil pressure in the cylinder chamber 5 of one overload prevention unit 10A becomes the breaking oil pressure pb, When reaching , the piston 33 of one control valve 2OA descends, and the main valve 26 separates from the main valve seat 31. At this time, when the piston 33 descends, the oil pressure in the communication passage 35 tends to rise, but since the piston 43 of the accumulator 29 descends, the rise in the oil pressure in the communication passage 35 is suppressed.

When the main valve 26 of one control valve 2OA leaves the main valve seat 31, the cylinder chamber 5 of the overload prevention unit IOA
The oil pressure inside the valve body escapes to the oil drain system 7 through the supply port 22, the main valve seat 31, and the oil drain port 24, so that the oil pressure gradually decreases. Eventually, when the pressure drops to Pb, -, the metal seal portion 4 breaks and the oil in the cylinder chamber 5 is rapidly returned to the tank 8 through the oil drainage system 7. Therefore, since the press load does not become larger than the set breaking load, overload is prevented.

At this time, when the hydraulic pressure in the cylinder chamber 5 of one overload prevention unit IOA is released, the oil supply lower 2 of the synchronized valve 70
The oil pressure supplied to A also decreases.

Then, the valve body 77B separates from the valve seat 75B, so the oil supply lower 2B is communicated with the oil drain lower 3B. As a result, the oil pressure in the cylinder chamber 5 of the other overload prevention unit IOB escapes to the oil drain system 7 through the oil supply lower 2B, communication #174B, and oil drain lower 3B of the synchronized valve 70, so that the metal seal portion 4 Upon rupture, the oil in the cylinder chamber 5 is rapidly returned to the tank 8 through the oil drain system 7. Thereby, when either one of the overload prevention units 10A and IOB breaks, the other one breaks in synchronism with the other, so it is possible to prevent the slide from tilting.

Therefore, according to this embodiment, each overload prevention unit IO
A. Since the rupture oil pressure can be set while keeping the oil pressure in the cylinder chamber 5 of the IOB at a constant set oil pressure, the two-way load prevention unit 10A.

The breaking oil pressure can be set to a low pressure without changing the oil pressure setting of 10B. This has the advantage that the range of application can be expanded and changes in mechanical deformation of the overload prevention unit 10A and IOB can be made slight.

In addition, the hydraulic pressure in the cylinder chamber 5 of the two-way load prevention units IOA and IOB is set to the same oil pressure, but the breaking oil pressure can be set separately for each overload prevention unit IOA and 10B, which allows for diversification. We can also respond to requests. Moreover, both road load prevention units IOA and IOH
Since the oil pressure settings are the same, there is no possibility that the slide will tilt.

Also, between the supply ports 22 of both control valves 2OA and 20B, one overload prevention unit) 10A, IO
Since a synchronized valve 70 is provided which releases the hydraulic pressure in the cylinder chamber 5 of the other overload prevention unit IOA, 1OB when the hydraulic pressure in the cylinder chamber 5 of B is released, the two-way load prevention unit 10A is provided.

When either one of the slides 10B breaks, the other can be broken immediately, so even if an overload occurs, it is possible to prevent the slide from tilting.

[Effects of the Invention] As described above, according to the present invention, the breaking load, that is, the breaking oil pressure is set separately for each overload prevention unit while keeping the oil pressure in the cylinder chamber of the two-way load prevention unit constant and the same set oil pressure. Can be set. This has the advantage that the breaking pressure can be set to a low pressure without changing the set oil pressure, so the range of application can be expanded, and changes in mechanical deformation of the overload prevention unit can be minimized. Also,
Since the hydraulic pressure setting for the two-way load prevention unit is the same and the breaking hydraulic pressure can be set separately, it is possible to meet the demands for diversification without causing the slide to tilt.

Moreover, when either one of the two-way load prevention units breaks, the other one breaks in synchrony with the other, making it possible to prevent the slide from tilting.

[Brief explanation of the drawing]

Figures 1 to 4 show one embodiment of the present invention.
2 is a cross-sectional view showing the control valve, FIG. 3 is a cross-sectional view showing the tuning valve, and FIG. 4 is a view for explaining the operation. This is a diagram for 4...Metal seal part, 5...Cylinder chamber, 10A, IOB...Overload prevention unit, 20A, 2
0B... Control valve, 22... Supply port, 23... Oil supply port, 24... Oil drain port, 26... Main valve, 7... Sub-valve, 8... Breaking pressure setting Mechanism, OA, 50B... Pressure regulating valve 0... Hydraulic pressure supply device, 0... Tuning valve. (Rupture pressure setting means)

Claims (1)

[Claims] (1) In a two-point press overload prevention device in which the slide is supported on the crankshaft via two sets of metal seal type overload prevention units, a supply port connected to the cylinder chamber of the overload prevention unit and an oil supply an oil drain port that communicates with the supply port; a main valve that opens and closes communication between the supply port and the oil drain port; and a main valve that opens and closes communication between the oil supply port and the oil drain port when the main valve is closed. Each of the overload prevention units is provided with a control valve having a sub-valve that communicates with the rupture pressure setting mechanism that sets the opening pressure of the main valve, and a control valve that is connected to the rupture pressure setting mechanism of each control valve. A rupture pressure setting means capable of independently setting the opening pressure of the main valve is provided, and the oil supply ports of each of the control valves are connected to a hydraulic pressure supply device by communicating with each other, and the oil supply ports of each of the control valves are connected to a hydraulic pressure supply device. A two-point press characterized in that it is connected to a synchronized valve that releases the hydraulic pressure in the cylinder chamber of the other overload prevention unit when the hydraulic pressure in the cylinder chamber of one of the overload prevention units is released. Overload protection device.