DE10230837A1 - Device for hot forming - Google Patents

Abstract

Hot deforming device comprises an overflow chamber (3) for a coolant arranged around an ejector shaft (4) in an annular manner, and a feed (5) for a coolant. The coolant is liquid nitrogen. Preferred Features: The device further comprises an upper ejector (6) arranged centrally in an upper die (2) and having holes for the output of coolant, a lower tool intermediate holder connected to a lower die, and a lower ejector connected to spraying agent circulations via the lower ejector shaft.

Description

The invention relates to a device for the hot forming of metal blanks consisting of a crank press with toggle mechanism for the production of flat, preferably ring-shaped, workpieces with predetermined measurements.

Such workpieces are usually produced by hot forming, also known as hot forging, with mechanical presses. Mechanical presses are driven by various systems, such as e.g. Eccentric presses and reaming presses. Such presses will be for the production of workpieces made of metallic blanks, which are required in large numbers. You assign each upper and lower dies as well as ejectors.

A serious problem is cooling the tools, the ejector and other highly stressed individual parts. An increase in Stroke rates leads for overheating of the forming tools combined with the shortening of the required time interval for lubrication and cooling - thus for the ineffectiveness of conventional Cooling or Lubricators. The consequences are uncontrollable temperature developments in the tool system.

From the patent literature are only few solutions especially for coping the problem of cooling known in powder pressing and hot forming.

From the DE 196 48 708 A1 Controlled cooling of a hot forming tool is known. This device is very complex and includes many measuring points, a thermal imager and a computing system. Using the thermal images, the computer controls the lubricant supply by means of several spray nozzles.

Furthermore, from the older one DE 3701 657 A1 a device for hot pressing parts made of metal powder with small inner holes known. The ram of such presses is thin and can be thermally overloaded at higher stroke rates and its dimensions can change. A predetermined temperature range of approx. 250 ° C to 600 ° C must therefore be maintained. For this purpose, liquid nitrogen is fed into an annular chamber around the tappet from below using complex designs. This device as a whole should enable the production of approximately 8 parts per minute. This special arrangement is not transferable to conventional hot forming.

With a further increase in the number of strokes or production such devices are no longer practical or too expensive.

The invention was therefore the problem based, a device for hot forming of metal blanks for the production of flat, ring-shaped workpieces to develop at stroke rates up to 30 strokes / minute.

This problem is solved according to the invention a device for hot forming with the characteristic features of claim 1 solved.

The device is then characterized by following features.

• 1. In the upper intermediate tool holder 1 , connected to the upper die 2 , is an overflow chamber 3 for a coolant included that
• 1.1. ring-shaped around the upper ejector shaft 4 is arranged and
• 1.2. a feeder 5 for a coolant, wherein
• 1.3. as a coolant preferably liquefied Nitrogen is used;
• 2. The upper ejector 6 , centered in the upper base die 2 arranged, has holes for the coolant outlet 7 on, with the ejector
• 2.1. six holes each 7 , arranged in a circle, has;
• 3. The lower intermediate tool holder 8th , connected to the lower basic die 9 , has 2 mutually sealed spray circuits 10 and 11 on, where
• 3.1. the lower spray circuit 10 with a highly viscous lubricant and
• 3.2. the upper spray circuit 11 is charged with a low-viscosity lubricant;
• 4. The lower ejector 12 over the lower ejector 13 with the spray circuits 10 and 11 is connected and spray orifices 14 and 15 has, wherein
• 4.1. the openings for the lower spray circuit 14 centric and
• 4.2. the openings for the upper spray circuit 15 are arranged in a circle.

The device according to the invention enables by changes in the die area or in the area of the intermediate tool holder in connection with the coolant supply and suitable lubricant circuits an increase the number of strokes to 30 strokes / minute and thus a reduction in production times in thermally stable hot forming processes. Another advantage the invention is that contrary to conventional cooling and lubrication in addition the cooling or lubrication of the ejector and ejector shafts also the entire tool can be kept thermally stable.

The invention is described below the drawings closer explained.

Show it,

1 An embodiment of the upper base die and the upper tool intermediate holder,

2 - A detail according to the embodiment. 1 .

3 An embodiment of the lower base die and the lower tool intermediate holder,

4 and 5 - Details of the embodiment acc. 3 ,

The presses according to the invention are used in production flat, ring-shaped Workpieces - preferably of synchronizer rings for Manual transmission used. These synchronizer rings consist of commercially available Messingleitlegierungen.

The presses work at 40 strokes / minute. First, the overflow chamber 3 about the feeder 5 filled with liquid nitrogen.

After the upward stroke of the press, the stroke of the upper ejector 6 corresponds, liquid nitrogen flows out of an overflow chamber 3 that are ring-shaped around the upper ejector shaft 4 is arranged through the holes 7 over the mandrel surface of the upper part of the tool. There are advantageously 6 holes on the respective diameter. The liquid nitrogen with its low temperature of -200 ° C to -210 ° C removes the excess heat from the tool.

Also become a double chamber 16 in the lower intermediate tool holder 8th for a lower and upper spray circuit 10 and 11 via spray openings 14 and 15 in the lower ejector 11 various lubricants and sprayed up as an air-lubricant mixture. This is the lower spray circuit 10 with highly viscous lubricant and the upper spray circuit 11 loaded with low viscosity lubricant. The central and circular arrangement of the lower spray openings has an advantageous effect.

The process of constant cooling and Lubrication of the tool system through a control system for the tool temperature.

1.

Oberer Tool line Switch

Second

upper Basic die

Third

overflow chamber for coolant

4th

Oberer Auswerferschaft

5th

Coolant supply

6th

Oberer ejector

7th

drilling in the upper ejector

8th.

lower Tool intermediate holder

9th

lower Basic die

10th

lower Sprühmittelkreislauf

11th

Oberer Sprühmittelkreislauf

12th

lower ejector

13th

lower Auswerferschaft

14th

spray openings of the lower circulation

15th

spray openings of the upper circulation

16th

double chamber for cycles

Claims (4)

Device for the hot forming of metal blanks, consisting of a crank press with a toggle mechanism for the production of flat, ring-shaped workpieces with predetermined dimensions, characterized by the following features, in the upper tool intermediate holder ( 1 ), connected to the upper basic die ( 2 ), is an overflow chamber ( 3 ) for a coolant, the 1.1 ring around the upper ejector shaft ( 4 ) is arranged and 1.2. a feeder ( 5 ) for a coolant, 1.3. liquefied nitrogen is preferably used as the coolant; The upper ejector ( 6 ), centered in the upper base die ( 2 ) arranged, has holes for the coolant outlet ( 7 ), with the ejector 2.1. each has six holes, arranged in a circle; The lower intermediate tool holder ( 8th ), connected to the lower basic die ( 9 ), has two, mutually sealed, spray circuits ( 10 and 11 ), where 3.1. the lower spray circuit ( 10 ) with a highly viscous lubricant and 3.2. the upper spray circuit ( 11 ) a low-viscosity lubricant is applied; The lower ejector ( 12 ) above the lower ejector shaft ( 13 ) with the spray medium circuits ( 10 and 11 ) is connected and spray openings ( 14 and 15 ), where 4.1. the openings for the lower spray circuit ( 14 ) centric and 4.2. the openings for the upper spray circuit run ( 15 ) are arranged in a circle.