DE102005026825A1 - Vehicle outer door handle manufacture involves filling injection tool cavity with plastic, purging plastic core with compressed gas from opposite direction, then feeding cooling gas from plastic injection direction - Google Patents

Abstract

Plastic is injected into a tool cavity(21) until completely full. The solid handle preform is then pierced(19) at the end of the plastic flow path corresponding to the rear end(17) of the handle. Purging gas(32) is blown in at the pierced point and flows in the opposite direction to plastic flow to form an internal chamber(34) of uniform wall thickness(35). The resulting hollow handle(10.2) is then pierced at a second point(29) at the front end(18) and cooling gas(33) fed into the internal chamber flows through to the handle rear end from which it leaves the tool cavity. Gas used for cooling and purging can be from the same or different sources. Coolant gas, preferably carbon dioxide, is supplied as a fluid at high pressure into the hollow handle at the second piercing point(29) and leaves as a gas via the first piercing point(19) at atmospheric pressure. Plastic purged from the solid preform may be either: a) returned to the processing machine feeding plastic to the tool or b) forced into an overflow reservoir(25) close to the feed runner(23) in the injection tool. The second pierced point for injecting cooling gas also lies close to the plastic feed runner. Outer surfaces of the handle may be painted or varnished.

Description

The The invention is directed to a method as defined in the preamble of Claim 1 specified type, where outside door handles are made for vehicles. The generated outside door handles can occasionally on its outer surface one Undergoing post-treatment, e.g. in the form of a paint job.

In the known method of this type ( DE 39 13 109 A1 ), the cavity in the injection mold is first completely filled with flowable plastic. Then, the core region of the plastic solid body initially produced in the cavity is pushed out of the cavity by a blow-by gas. This is done in the known method by two nozzles at the two ends of the resulting hollow body. In this method, although one obtains a satisfactory outer surface on the hollow body, but it takes a relatively long time until the hollow body is solidified so that it can be removed from the injection mold. This long process time increases the manufacturing cost of the molded part.

Out For this reason, one has as a fluid for blowing out the core inside of the hollow body to be formed liquids used, such as water, which have a higher heat capacity. The duration of the procedure but could not be reduced, because the interior of the resulting Hollow body afterwards by blowing in gas, e.g. Air, to be cleaned of fluid had to. Again, this procedure was time consuming.

There are also known methods of another kind ( GB 2 352 206 A . DE 40 24 549 A1 . EP 1 259 368 B1 The cavity of the injection mold is only partially filled with plastic and then blown from one or the other end of the hollow body, a gas that fulfills two functions according to a so-called "half-shot" formed as a hollow body molding in the plastic injection mold The first function is to push the plastic to the other end of the cavity, and as a second function it also forms the cavity in the interior of the plastic, partially filling the plastic to create imperfections on the surface of the resulting cavity As the plastic propagation in the cavity occurs simultaneously with the formation of the cavity in the interior, the processes are difficult to control and in some cases too thin wall thicknesses are created in the hollow produced shapes which reduces the quality of the finished part.

Of the Invention is based on the object, a process for the preparation an outside door handle according to the preamble to develop from claim 1, which is a manufacture of the outside door handle with perfect outer surface reached. This is inventively the measures listed in claim 1 achieved the following special significance.

At the inventive method become two gases in two consecutive process steps introduced in the opposite direction to each other in the interior of the cavity to there a tubular handle blank let develop. This is done in the end of the flow path of Plastic in the cavity located plastic solid body pierced a first time, causing there a rear end of the pipe Handle blanks arises. By this first pier is the already known blow-off gas filled until, until the excess masses into the screw or in an overflow located next to the inlet channel be pushed out. The blow-out direction is the previous flow path of the Plastic opposite.

For the mentioned second Gas will be in the cavity resulting handle blank opposite, namely in Area of flow path beginning from the plastic, also pierced, causing a second there Puncture site is created. This forms a front pipe end, in which Now again in the direction of the previous plastic flow path cooling gas introduced into the interior becomes. The cooling gas flows through passes the inside of the handle blank and joins the one of the first Parting point formed from the rear end of the tube from the cavity. Because the flow directions in the individual process steps during insertion of the plastic, the blow-out gas and the cooling gas alternate with each other, results in a uniform wall structure of the outside door handle. Furthermore will the quality the finished outside door handle improved for the following reason.

By the opposing current The first two process steps result in a layered manner different construction of the walls in the handle blank, because the particles contained in the enamel while streaming in the outer layers of the Wand oriented differently than in the opposite by the blow-by gas oriented inner layers. The particles in the plastic masses consist of e.g. made of glass fibers, which have an elongated structure. This Structure is of the opposing currents of the method according to the invention affected.

Further activities and advantages of the invention will become apparent from the following description and the drawings. In the drawings is the inventive method represented in different process steps. Show it

1 the injection mold with a still empty cavity, which is used to produce an outside door handle for a vehicle,

2 the form of 1 after completion of a first process step, where the cavity has been completely filled with plastic,

3 the next process step, where, in the opposite direction to the flow path of the plastic, a blow-by gas is passed through the cavity, which creates a handle blank there,

4 a last process step, where a cooling gas in the direction opposite to the blow-by gas, but in the direction of the flow path of the plastic flows through the mold, and

5 a side view of the finished outside door handle.

With the method according to the invention, the in 5 shown outside door handle 10.0 produced for motor vehicles. The handle 10.0 has at its one end of the handle 11 an approach 13.0 with a bearing opening 14 for pivoting the handle 10.0 when used as intended. At the opposite end of the handle 12 is a jetty 15.0 molded, the projections 16 having. When used as intended by the handle 10.0 the projections act 16 with a built-in lock on the vehicle, which is then opened or closed.

In 1 schematically the closed injection mold is shown in section, wherein initially a cavity 21 is provided, which the future outer surface 39 of in 5 shown handle 10.0 certainly. To initiate a flowable, in 2 punctuated plastic 30 the injection mold has an inlet 22 , which then has a front entry channel 23 connects, then via a rear entrance channel 24 in the one end of the actual cavity 21 empties. The cavity 21 can be, apart from a central body, even in an initial area 27 and in an end area 28 divided. The starting area 27 is used to make the in 5 described bridge 15.0 and the end area 28 for generating the approach 13.0 , In the injection mold 20 There is also a cavity in the present case 25 for a plastic excess, which is related to 3 will be described in more detail. This cavity 25 is like a "dead end" to the entrance channel 23 . 24 connected to a prominent distributor 26 between its front and rear channel parts 23 . 24 , The excess cavity 25 has spiral shape here.

In a first process step, the already mentioned plastic 30 into the cavity 21 introduced. In 1 is the flow path 31 indicated by dash-dotted arrows. It can be seen that the flow path 31 directionally from the rear entrance channel 24 in the starting area 27 the cavity 21 enters and flows to the extreme end, namely up to and including the end region 28 the cavity 21 , The result is in 2 shown.

2 shows that the highlighted by dot hatching still liquid plastic 30 the cavity 21 completely fills and this from the starting area 27 to the last corner of the end area 28 fills. This results in the cavity 21 first a plastic full grip 10.1 , Of course, there are also the front and the rear entrance channel 23 . 24 and the intervening distributor 26 initially filled with liquid plastic. The one behind the distributor 26 lying cavity 25 in the injection mold 20 but it is still completely empty. At the cooling inner surface of the cavity 21 The plastic starts immediately 30 to solidify.

At the beginning of the next process step, the plastic full grip 10.0 at the in 2 With 19 marked point, which should therefore be called "first piercing point." This first pier 19 is in the end area 28 the cavity 21 in distance from the profiles relevant to the later lock operation of the future in 5 described approach 13.0 , The result of the next process step is in 3 to recognize.

At the first pier 19 is located in 3 visible pipe end 17 through which a gas 32 in the direction of the arrows inside the plastic-filled cavity 21 is initiated while pushing out the viscous core area of the plastic filling at the other end. Because, as already mentioned, the peripheral areas have solidified, there remain walls, while in the core area a cavity 34 arises. The one from the cavity 34 displaced plastic is in the present case on the distributor 26 in the vacant cavity 25 the injection mold 20 pushed in and can freeze there. Because the gas 32 for blowing out the plastic 30 from the core area, it should be briefly below "blow-by gas 32 be designated.

Like a comparison of the arrows 31 in 1 With the arrows 32 in 3 results, is the flow direction of the blow-out gas 32 the above-described flow path 31 of the plastic 30 opposite direction. That is remarkable. The blow-by gas enters through with respect to the above-described pipe end 17 opposite pipe end 18 from the injection mold in the area of the distributor 26 out. The blow-off gas 32 is operated at a pressure of 150 bar to 350 bar through the plastic handle 10.1 driven. Regarding the plastic flow path 31 is the latter pipe end 18 at the beginning of the flow path and should therefore be referred to as the "front end of the pipe", while the opposite end of the pipe 17 then "rear pipe end" must be called between the two pipe ends 17 . 18 thus creates a tubular handle blank 10.2 , which is a particularly stable, uniform wall thickness 35 receives. The wall thickness 35 has because of the opposite direction of flow when plastic 31 on the one hand and blowing out through the gas 32 on the other hand, an opposing layer structure by provided in the plastic particles, such as glass fibers. This affects a high strength of the later door outside handle 10.0 from 5 out.

In the following process step, the treatment of the created handle blank is reversed 10.2 in the injection mold 20 in turn; the generated tubular handle blank 10.2 is at 29 pierced and through the front end of the pipe 18 will be another gas 33 introduced. This additional gas occurs at the distributor 26 in the hollow body 20.2 one and can only over the hollow rear entrance channel 24 in the main part of the cavity 21 to the rear end of the pipe 17 flow while the front entrance channel 21 and the excess cavity 25 with the plastic 30 stay filled. Proven of the arrows 33 the flow of this further gas, as I said, in the opposite direction to the blow-out gas 32 and is therefore partially back to the flow path 31 of the plastic 30 according to 1 and 2 in accordance. Because this is more gas 33 the function has the hollow body 10.2 to cool, it should be referred to below as "cooling gas".

The cooling gas 33 flows through the cavity 34 in the tubular handle blank 10.2 and occurs at the rear end of the pipe 17 from the injection mold 20 out into the open. As a cooling gas 33 Advantageously carbon dioxide is used. It occurs at the second attachment point 29 in liquid form, evaporates inside the cavity 34 and enters as carbon dioxide gas at the rear end of the pipe 17 out again. The high evaporation cold leads to a surprisingly fast hardening of the wall 36 , why the finished outside door handle according 4 after a short time, which can be about 30 seconds, from the injection mold 20 can be removed. The reduced production time lowers the manufacturing cost.

After solidification of the plastic 30 will that be in 4 shown structure as a whole from the injection mold 20 removed. The in 4 left part is then the finished outside door handle 10.0 that of the tubular rest 37 in the area of the rear entrance channel 24 originated, only needs to be separated. At the transition point to the starting area 27 the cavity 21 forms the entrance channel 24 a rejuvenation. After separating the pipe residue 37 with the other excess amounts of the plastic 30 arises at this transition point a small cut opening 38 in the back of the according to 5 generated web 15 , In the opposite approach 13.0 remains in the side surface, the opening of the described rear pipe end 17 visible, noticeable. The outside of the generated handle blank 10.2 lying plastic masses 30 can be re-melted and used to make a new outside door handle.

The generated outside door handle of 5 has an outer surface free from damage 39 because during the described first phase of the process, the entire cavity 21 completely with plastic 20 was completed. Only then did the described second process stage begin with the introduction of the blow-off gas 32 that captured only the inner areas. The perfect outer surface 39 can then also be treated very successfully, eg by painting. This gives the final exterior door handle 10.0 an extraordinarily uniform and beautiful appearance.

It would be an alternative of the described method conceivable, which consists in the excess plastic masses 30 instead of in the described cavity 25 , from manifold over through the front inlet channel 23 and the inlet 22 back to a screw not shown in detail, which in the first process stage according to 2 the plastic 30 into the cavity 21 injects. Then, in the area of the screw, the plastic can 30 liquefy again and stands for the "next shot" in the creation of a subsequent outside door handle 10.0 again available.

10.0

Outside door handle ( 5 )

10.1

Plastic filling, plastic handle ( 2 )

10.2

tubular handle blank ( 3 . 4 )

11

first end of 10.0 ( 5 )

12

second end of 10.0 ( 5 )

13.0

Approach 11 ( 5 )

14

Bearing opening at 13.0 ( 5 )

15.0

Dock at 12 ( 5 )

16

Projections on 15.0 ( 5 )

17

at the rear end of the pipe 19

18

at the front end of the pipe 29

19

first pier at 17

20

injection mold

21

Cavity for 10.2 in 20

22

Inlet for 30 in 20

23

front entry channel for 30

24

rear entrance channel for 30

25

Overflow Cavity for excess

26

Distributor between 23 . 24 . 25

27

Initial range of 21 For 15.0 ( 1 )

28

End of 21 For 13.0 ( 1 )

29

second pier at 18

30

plastic

31

Flow path from 30 in 21

32

Flow arrow from the blow-off gas ( 3 )

33

Flow arrow of the cooling gas ( 4 )

34

Interior of 10.2 , Cavity ( 3 . 4 )

35

Wall thickness of 10.2 ( 3 )

36

Wall of 10.2 ( 4 )

37

Tube remainder ( 4 )

38

Cut opening on 15.0 ( 5 )

39

Outer surface of 10.0

Claims (11)

Method for producing an outside door handle ( 10.0 ) for vehicles, wherein a cavity ( 21 ) in an injection mold ( 20 ) generated by the outer surface of the outside door handle ( 10.0 ), in the cavity ( 21 ) by plastic injection molding a tubular handle blank ( 10.2 ) for the outside door handle ( 10.0 ), the handle blank ( 10.2 ) two pipe ends ( 17 . 18 ), namely a front pipe end ( 18 ) and a rear pipe end ( 17 ) by first in the area of the front pipe end ( 18 ) of the handle blank to be formed ( 10.2 ) the flow path ( 31 ) of plastic ( 30 ) in the cavity ( 21 ) and is introduced until the plastic ( 30 ) the cavity ( 21 ), the other, rear tube end ( 17 ) and a plastic full grip ( 10.1 ) in the cavity ( 21 ), then a blow-by gas ( 32 ) inside the plastic ( 30 ) filled cavity ( 21 ) is introduced and the blow-out gas ( 32 ) the viscous core region of the plastic filling ( 10.1 ) from the cavity ( 21 ), whereby the pressed out plastic ( 30 ) outside the cavity ( 21 ) ( 25 ), possibly later for the production of a new exterior door handle ( 10.0 ), characterized in that after filling the whole cavity ( 21 ) the local plastic handle ( 10.1 ) in the end region of the flow path ( 31 ) of the plastic ( 30 ) ( 19 ) and at this first piercing point ( 19 ) the rear pipe end ( 17 ) arises that at this first piercing point ( 19 ) the blow-off gas ( 32 ) in the opposite direction to the flow path ( 31 ) of the plastic ( 30 ) into the cavity ( 21 ) until a handle blank ( 10.2 ) with the desired uniform wall thickness ( 35 ), then that in the cavity ( 21 ) located handle blank ( 10.2 ) in the region of the flow path beginning of the plastic ( 30 ) also pierced ( 29 ), whereby at this second piercing point ( 29 ) the front pipe end ( 17 ), and then at the second piercing point ( 29 ) in the direction of the preceding plastic flow path ( 31 ) a cooling gas ( 33 ) in the interior ( 34 ) of the handle blank ( 10.2 ) is introduced through the interior ( 34 ) of the handle blank ( 10.2 ) and at which from the first piercing point ( 19 ) formed rear pipe end ( 17 ) continuously from the cavity ( 21 ) is drained. Method according to claim 1, characterized in that the cooling gas ( 33 ) of the same kind as the blow-off gas ( 32 ). Method according to claim 1, characterized in that the cooling gas ( 33 ) of a different kind than the blow-off gas ( 32 ). Method according to claim 2 or 3, characterized in that the cooling gas ( 33 ) with a high pressure at the second piercing point ( 29 ) in the generated handle blank ( 10.2 ), but at its first piercing point ( 19 ) flows against atmospheric pressure. Method according to one or claims 1 to 4, characterized in that the cooling gas ( 33 ) at the second piercing point ( 29 ) is supplied in liquid form, but at the first piercing point ( 19 ) emerges in gaseous form. Method according to claim 5, characterized in that as cooling gas ( 33 ) Carbon dioxide is used. Method according to one of claims 1 to 6, characterized in that from the plastic solid body ( 10.1 ) through the blow-by gas ( 32 ) extruded plastic masses ( 30 ) are returned to a screw, through which the plastic ( 30 ) into the cavity ( 21 ) is introduced. Method according to one of claims 1 to 6, characterized in that from the plastic solid body ( 10.1 ) through the blow-by gas ( 32 ) extruded plastic masses ( 30 ) in as overflow ( 25 ) acting cavity ( 25 ) of the injection mold ( 20 ), which adjoin an entrance channel ( 23 . 24 ) of the plastic ( 30 ) in the injection mold ( 20 ) is located. A method according to claim 8, characterized gekenn records that the second piercing point ( 29 ) for the cooling gas ( 33 ) in the injection mold ( 20 ) in the area of the entrance channel ( 23 . 24 . 25 ) for the plastic ( 30 ) is produced. Method according to one of claims 1 to 9, characterized in that the outside door handle ( 10.0 ) on its outer surface ( 39 ) is treated. Method according to claim 10, characterized in that that the aftertreatment consists of a coating.