RU2424110C1 - Electromagnetic stamping press for shoe parts production - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to light industry, particularly, to shoe production. Proposed press comprises foundation, rotary support, plate, power drive and capacitor. Power drive is made up of solenoid-type electromagnet with its core made up of hammer. Said electromagnet mat create impact force to cut shoe parts. Press is provided with substrate. Plate is provided with groove to accommodate cutter arranged on substrate. Said cutter may accommodate shoe part material and move relative to said hammer. Said hammer is provided with tip, its length exceeding maximum width of cutter.

EFFECT: smaller area and weight of hammer.

2 dwg

Description

The proposed technical solution relates to light industry, namely to die-cutting presses for the manufacture of shoe parts, and can be used in cutting and cutting shops of shoe factories.

Known die-cutting presses (Lebedev B.C. Equipment for consumer services. M .: Nauka, 1982. - 132 p.), In which the process of cutting down shoe parts is carried out by an electro-hydraulic drive containing an electric motor, a power hydraulic cylinder, a control device, an executive body - a drummer. A sheet material is placed on a die cutting table, and a cutter is placed on top of it. The drummer of the press acts on the cutter, and the control circuit disables the operation of the hydraulic cylinder. The disadvantages of such presses are high power consumption, large dimensions and weight.

The use of electromagnetic drives in engineering and technology is quite large. Their designs are diverse, designed mainly for the power movement of mechanisms, and their work is carried out in static mode (AS USSR (SU) No. 1283115, class B30B 15/00, B30B 15/2, F16D 11/00; econ. GDR (DD) Patent No. 262621, Cl. B30B 11/00, B22C 15/00).

In the invention (AS USSR (SU) No. 103200, B26D 5/06, 1956) “Device for cutting chilled glass” the use of a power drive is proposed — an electromagnet of the solenoid type, the core of which is made in the form of a striker. This device is designed for cutting chilled glass by cutting a groove along which the glass breaks. Chilled glass, unlike shoe materials, has significant mechanical hardness and fragility. And therefore, hitting it with a cutter, rigidly fixed to the core (anchor) of the electromagnet, must be short-term with little force and amplitude. When an electromagnet is supplied with a sinusoidal current of industrial frequency, a significant fraction of the total current power is the reactive force, so the power factor (cos φ) is very small, and the core oscillates at twice the frequency. The duration of one pulse of the torch exposure to the glass is determined by the half-cycle of the supply voltage (10 ms).

With such a duration of a pulsed shock, elastic materials for shoes do not have time to deform to the state at which the cutting process begins. A large impact force of the core with the cutter on the material in this device can be achieved by increasing the current strength, which will lead to saturation of the magnetic circuit and a relative decrease in the magnetomotive force. To eliminate this phenomenon (in a static mode of operation of an electromagnet, when its winding is connected to a sinusoidal current source), it is necessary to significantly increase the mass and dimensions of the magnetic circuit. At the same time, the inertia of the armature of the electromagnet increases, the electric loss of current power increases. Thus, the use of a power drive as. (SU) 103200, B26D 5/06, 1956, without changing the design and operation mode (strength, amplitude and duration of the pulse exposure) in cutting processes for shoe materials it is not possible.

There is a punching machine brand PV-10, described in the book of Lebedev B.C. "Technological equipment for shoe repair enterprises", ed. Light Industry, Moscow, 1972, p. 32, Fig. 11.7. The die cutting press PV-10 contains a bed, a swivel bracket, a plate, a striker and its power drive. The power drive consists of an electric motor, gear pulleys that transmit the rotation of the motor shaft to the eccentric shaft, to which a crank pin and a connecting rod are connected, which serve to convert the movement. Next, the converted rotational motion into a reciprocating motion is transmitted to the drummer using other parts. The press also contains a mechanism for turning on and automatically turning off.

This press uses a power drive with a sufficiently large current power. This is due to the need for a one-time impact-push impact of the impactor on the cutter for cutting down shoe parts from materials with elastic properties (in contrast to materials with solid properties). Moreover, the process of converting electrical energy into useful mechanical energy proceeds with large electrical and mechanical losses at a lower efficiency. and cosφ, the increased cost of manufacturing shoe parts. The die-cutting press of the prototype has large dimensions and weight, and therefore makes it difficult to use it in the conditions of small workshops for the individual manufacture of shoes.

The closest in technical essence to the claimed technical solution is a die-cutting press described in the source of information V.I. Bogdanov, RU 2000109986, published December 27, 2001, adopted as a prototype.

The electromagnetic press of the prototype contains a bed, a swivel bracket, a plate, a drummer and its power drive. The power drive of the electromagnetic die-cutting press of the prototype is made in the form of an electromagnet of the solenoid type, the core of which is made in the form of a striker, the press contains a capacitor. The shock force of an electromagnet is created by converting the energy of the electric field of a charged capacitor into the energy of the magnetic field of an electromagnet winding. Felling of the material is carried out by a series of pulsed power shocks by switching the charged capacitor and the winding of the electromagnet with an electronic key, in the sum equivalent to the force of a single shock.

The disadvantages of the design of the electromagnetic press of the prototype and its technological process include the relatively large mass of the hammer and its surface area equal to the area of the torch, as well as the relative position of the torch and the material affected by the torch. The prototype press drummer acts on the cutter, which, along the entire length of the blade, is embedded in the sheet material from which the shoes are made.

The main objective of the proposed technical solution is to reduce the surface area of the hammer, facing the material with the cutter, and its mass.

The problem is achieved in that for many materials used for the manufacture of shoe parts, the material in the area exceeding the area of the shoe part can be placed on the cutter. In this case, the drummer is made with a small cross-sectional area facing the material of the shoe part, and with a length exceeding the largest width of the cutter. This will allow for a small cross-sectional area of the striker to create a larger specific shock pressure p, p = F / A, N / m ² , i.e. the ratio of the force F acting perpendicular to the surface to surface area A (Kuhling X. Physics Handbook: Translated from German - M .: Mir, 1982. - 520 p., Formula F.8.1, p. 113) of the impactor on material in the process of cutting down shoe details. In this case, the shoe material is mounted on the cutter along its entire length not simultaneously, but gradually as it moves along with the cutter on the substrate along the bore in the frame relative to the drummer. Dimensions, weight, energy consumption of the electromagnetic press will be less, providing greater versatility.

The technological process of manufacturing shoe parts by the proposed electromagnetic press proceeds as follows (Fig. 1. - functional diagram of the press).

On the bed 1, in its bore of the plate, a cutter 8 is installed on the substrate 11. On top of the cutter, the material of the shoe 9 is laid. Using the rotary bracket 2, the electromagnet with the core and hammer 3 is made with a small cross-sectional area facing the material of the shoe and with a length of exceeding the largest width of the cutter 8, set over the material of the shoe. The material in area exceeds the area of the shoe detail. Connect through a resistor R1 (figure 2, a variant of the electrical circuit of the press) capacitor 7 to a constant current source. Using the control unit 10, a charged capacitor 7 is connected to the winding of the electromagnet 5. A transient occurs in the electrical circuit. A discharge current pulse in an electromagnet winding creates a pulsed magnetomotive force (MDS) and a pulsed magnetic flux. In this case, a mechanical force arises that pushes the core with the hammer 3 of the electromagnet. The drummer acts on the shoe material 9, so that the material does not fit onto the cutter 8 simultaneously along the entire length of the cutter blade. With the disappearance of the magnetic flux, the return spring 4 sets the core with the hammer in its original position. Using the substrate 11 in the bore of the bed plate, the cutter 8 and the material 9 superimposed on it, at the end of the discharge pulse, are moved relative to the drummer with tip 3 until the shoe part is completely cut down.

In the electric circuit of an electromagnetic die-cutting press, in order to determine the law of change in current and the rise time of the current to an amplitude value, one should consider the case of a short circuit of a charged capacitor to an electromagnet winding, the equivalent circuit of which is represented by a series connection of a resistor R and an ideal coil with inductance L. According to the theory of transient for this case (Theoretical foundations of electrical engineering. / Under the editorship of A.E. Kaplyansky - M .: Higher school, 1972, p.245-249) ny capacitor C to the voltage U is closed on an electrical circuit with a series connection of a resistor R and an inductive coil L. The differential equation of the second law of Kirchhoff describing transition process for this case will be homogeneous

его характеристическое уравнениеor considering

its characteristic equation

has two roots

The final expressions of current and voltage across the coil with inductance L and capacitor C have the form

,

,

,

,

,

,

, корни характеристического уравнения P₁ и Р₂ будут вещественными Р₁<0 и Р₂<0, | Р₁|<|Р₂|. При этом величина тока, начинаясь с нуля, всегда отрицательная (соответствует току разряда конденсатора), а напряжение на катушке возникает скачком, равным - U. По истечении времени от 0 до t₀, когдаThe nature of the transition process depends on the magnitude of the active resistance R and the inductance L of the electromagnet winding, the capacitance of the capacitor C and the voltage of the current source U. In the proposed technical solution, taking into account the specifics of the cutting technology, the transition process in the electric circuit of the electromagnetic cutting press should be aperiodic, but not oscillatory. This condition is satisfied if

, the roots of the characteristic equation P ₁ and P ₂ will be real P ₁ <0 and P ₂ <0, | P ₁ | <| P ₂ |. In this case, the current value, starting from zero, is always negative (corresponds to the discharge current of the capacitor), and the voltage on the coil occurs in a jump equal to - U. After a time from 0 to t ₀ , when

the current in the winding of the electromagnet takes the largest (amplitude) value. The voltage on the winding of the electromagnet takes on its greatest value after a time t = 2t ₀ , which can be taken in a single current pulse. In the electric circuit, the energy of the electric field of the capacitor C is exchanged into the energy of the magnetic field of the winding of the electromagnet with inductance L, and at the active resistance of the winding R, the electric energy is converted into thermal energy.

From the analysis of the transition process it follows that the values of R, L, C, U, as well as the frequency of the discharge of the capacitor are the settings and calculation of the electric circuit of the electromagnetic die-cutting press when it is used to cut down shoe parts from materials with different physical and mechanical properties.

In an experiment with a typical MIS-5200 electromagnet used in the PVG-8-0 hydraulic press with a nominal static force of 6 kg, using a 4000 μF capacitor charged to a voltage of 300 V, a force pulse was obtained in about 30–40 ms, sufficient for lifting loads up to 100 kg to a height of 2 cm.

Claims (1)

An electromagnetic die-cutting press for the manufacture of shoe parts, comprising a bed, a swivel bracket, a plate, a power drive made in the form of an electromagnet of the solenoid type, the core of which is made in the form of a striker, and a capacitor, while the electromagnet is made with the possibility of creating shock force by converting the energy of the electric field charged capacitor into the energy of the magnetic field of the electromagnet winding and cutting material of the shoe part by a series of pulsed force blows to the cutter at the switching the charged capacitor and the winding of the electromagnet with an electronic key, characterized in that it is provided with a substrate, the plate is made with a bore in which a cutter is located on the substrate, configured to place material of the shoe part on it and move relative to the drummer, and the drummer is made with a tip having length exceeding the largest width of the torch.

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