KR19980082704A - Seal manufacturing method and press device - Google Patents

Abstract

A method of manufacturing a seal in a cylinder head of a vehicle motor includes providing a bearing groove in a cylinder head of a vehicle motor and providing a mold member for working with the bearing groove to form a seal. The sealing material is introduced into the mold member to provide a limited excess material that exceeds the amount of sealing material required for bearing groove filling. The hardening of the sealing material contained in the bearing grooves and the mold member takes place under pressure. The press apparatus for carrying out this method includes a mold member having a receiving groove for operating with a bearing groove of the cylinder head.

Description

Seal manufacturing method and press device

The present invention relates to a method for manufacturing a seal in a shaped body, in particular a cylinder head of a vehicle motor, characterized in that the cylinder head is a die-cast member, has a bearing groove for accommodating the seal, and the seal is applied under pressure, It also relates to a press device, in particular to a cylinder head of a vehicle motor, the cylinder head comprising a bearing groove for the seal.

Cylinder head consisting of a die-cast member of a vehicle motor by applying a sealing material such as silicone elastomer to the bearing groove of the cylinder head under high pressure using a cartridge gun or other application device and attaching the seal as fixedly as possible in the bearing groove. It is known to apply seals to.

From the German published pamphlet 30 18 074 it is known to apply a silicone elastomer seal in one or more layers to cure the seal by evaporating the solvent at room temperature.

The problem with such seals is that, for example, due to the manufacturing speed required in the automotive industry, droplets are formed which destroy the sealing properties of the seal within the seal. Therefore, it is known to apply a large pressure such as 60 bar. However, this pressure requires a fairly stable support for cylinder head gaskets composed of molded metal plates or diecast members and the high pressure press apparatus required for seal applications is very expensive and complex because the application must be automated. Therefore, all joints, such as the application arm, must withstand high pressure and the accuracy of the form must not be ignored.

In addition, it is known to make seals as extruded profiles, and various types of seals are known. Such seals are known, for example, from the German published pamphlets 24 37 567 and 25 51 360. In addition to oils, materials that are resistant to acidic components contained in oils are selected and used.

However, hot and low viscosity oils tend to flow down the seal, especially when a diecast cylinder head with greater surface roughness than the metal plate cover is used.

It is therefore an object of the present invention to provide a press device that provides a permanent sealing action not only for the production of seals from molded parts but also for low viscosity oils and die-cast objects, and at the same time the manufacturing cost is low and the required accuracy and specifications It must be maintained.

According to the invention the method for producing a seal from a shaped body, such as a cylinder head of a vehicle motor, is characterized by the following steps:

Providing a bearing groove in the cylinder head;

Providing a mold member that cooperates with the bearing groove to form a seal;

Injecting the sealing material into the mold member to provide a finite excess exceeding the amount of sealing material required to fill the bearing grooves;

The sealing material contained in the bearing groove and the mold member is cured under pressure to form a seal.

The injecting step includes pushing a limited excess into the bearing groove while in the plastically deformable state prior to the curing step.

The injection step includes applying a pressure of 1.5 to 6 bar to the sealing material during injection.

A pressure of 3 bar is preferred.

The infusion step includes the application of the sealing material to a low pressure metering and mixing device, with the preference for two-component silicone elastomers enthusiastic as the sealing material.

The method includes heating the sealing material prior to introducing the sealing material into the mold member and / or heating the cylinder head prior to introducing the sealing material and / or heating the mold member prior to introducing the sealing material. do.

The mold member has a low mass and includes a receiving groove and the receiving groove area is reinforced.

The method further includes providing a receiving groove having a non-stick surface layer to promote seal removal from the mold member.

The non-sticky surface is made of polytetrafluoro ethylene.

The sealing material is free of solvents, in particular ethyl acetate.

The press apparatus of the present invention for applying a seal to a shaped body, such as a cylinder head of a vehicle motor, is characterized by the following: The shaped body or cylinder head comprises a bearing groove for accommodating the seal:

A mold member having a groove that receives a finite excess exceeding the amount of sealing material required to fill the bearing groove, the press device pushes the finite excess into the bearing groove and the mold member and bearing groove are provided with a sealing material to be cured under heating. Work together to enclose.

The mold member is positioned so that the receiving groove faces upward and the sealing material is injected into the receiving groove from above.

The press apparatus further includes a heating device for periodically heating at least one of the cylinder head and the mold member to a preheating temperature and a curing temperature and further includes a preheating zone for preheating the cylinder head advanced to the press apparatus.

The preheating temperature is about 60 ° C and the curing temperature is about 150 ° C.

Surprisingly, the present invention prevents oil from flowing down the seal without the use of drops in the seal injected into the bearing grooves of the shaped body and without the need for high pressure application during curing. By first applying the seal to the receiving groove of the mold member, no drops are generated in the active face of the seal that will later be placed on the cylinder head or other opposite side of the molded body. Generally, during low pressure application no drops are formed in the base and at least the drops move upwards, ie outside the active surface area of the seal. Droplets are removed by pressing the sealing material between the molded body (eg, cylinder head) and the mold member. In general, however, the formation of droplets at the bearing groove base is not critical since the droplets are completely surrounded by the sealing material.

Obviously, during the compression between the mold member and the molded body, the sealing material is tightly bonded with the surrounding material, in particular the diecast member, to completely prevent the flow of oil between the seal and the groove.

Compared to the high pressure method for applying the seal directly to the bearing groove, the method of the present invention has the advantage that a significantly reduced pressure can be applied. Surprisingly, high pressure is not required to press the mold member onto the molded body. However, suitable conditions must be met for the curing step.

In one embodiment it is proposed to thermoset the seal to a temperature of 150 ° C. The limited excess of filling the bearing grooves and providing additional material relative to the size of the bearing grooves provides sufficient safety margin to completely fill the bearing grooves and non-shrink material is preferred during curing.

Particular preference is given to heat resistant bicomponent silicone elastomers which provide the required mechanical properties and excellent recovery aspects.

Using the present invention, molded bodies, such as die cast members, including seals can be prefabricated and supplied to the motor manufacturer, for example, in a prefabricated state.

1 is a cross-sectional view of a seal applied to a mold member used in a first embodiment of the present invention.

2 shows the seal of FIG. 1 after the pressing step, curing step and removal between the mold member and the molded body.

Figure 3 schematically shows the application of the sealing material to the receiving groove of the mold member in another embodiment of the invention.

4 shows the seal injected into the receiving groove of the mold member of FIG. 3 prior to positioning the shaped body.

* Code Description

10 ... seal 12 ... mold member

14 ... receiving groove 16 ... base

18 ... flank 20 ... flank

22 ... non-sticky layer 24 ... excess material

26 ... bearing groove 28 ... surface

30 ... surface 32 ... molded body

34 ... active surface 36 ... nozzle

38, 40 ... arrows 42 ... tips

1 shows how the seal 10 is applied to the mold member 12. The mold member 12 has a receiving groove 14 comprising a base 10, a groove flank 18, and a side face 20 having a non-sticky layer 22 extending over the entire surface. The non-sticky layer 22 allows for easy removal of the seal from the mold member and is non-adhesive to the seal 10 material, such as silicone elastomer.

The seal 10 is introduced into the mold member receiving groove 14 at room temperature (about 20 ° C.) and the excess material 24 protrudes over the side surface 20. The excess material 24 is such that it completely fills the bearing groove 26 indicated by the dashed line in FIG. 1. Thus, the sum of the surfaces 28 is greater than the surface 30 and the ratio of the surfaces can be calculated or experimentally determined.

Other shapes of excess material 24 are also possible. It is preferable to manufacture simply using a low pressure application device and the preheating temperature is chosen so that the sealing material of the seal 10 is sufficiently viscous to be fully introduced into the groove 26.

Immediately after application of the sealing material to the receiving groove 14, a heating device, not shown, is turned on to raise the temperature to the extent that curing starts. At the same time, the molded body 32 shown in FIG. 1 is placed on the mold member 12 and pressure is applied to them to deform the excess material 24 so that the seal 10 has the required shape in the bearing groove 26 region. . Since the surface 30 is slightly smaller than the surface 28, the excess sealing material of the seal 10 is pushed to the side. It does not matter whether this material remains in the molded body 32 as it does not interfere with the actual sealing function. However, if necessary, this material can be removed by any suitable means.

The temperature of the unit composed of the molded body 32 and the mold member 12 is maintained at the curing temperature for as long as necessary for curing the seal 10. For example, the time is 1 to 2 minutes. As soon as the sealing material for the seal 10 is in the state shown in FIG. 1, it is preferred to achieve a work cycle in which heating of the mold member and the molded body begins.

It is desirable for the mold member 12 to have a hollow profile that is only supported in the region of the receiving groove 14 to have a relatively minimal heat capacity and to withstand the applied pressure.

Particular preference is given to the need for low pressure application to seal manufacture. Therefore, the load required for supporting the molded body 32 in the form of the cylinder head and the mold member 12 is greatly reduced.

Another embodiment of the method is shown in FIGS. 3 and 4. The shape of the seal 10 according to FIGS. 1 and 2 can be introduced without drops, in particular a small number of drops in the active surface 34 region, while the embodiment according to FIGS. 3 and 4 has a high sealing despite low pressure. Even at the rate of material application it is more preferred in terms of preventing drops. As part of the low pressure application device, the application nozzle 36 introduces a sealing material for the seal 10 into the receiving groove 14 from above. The base 16 of the groove 14 is of special design to deflect the flow of introduced sealing material. As can be seen by the arrows 38, 40 of FIG. 3, the sealing material is laterally deflected by the tip 42 and the adjacent flank of the base 16 surface of the groove 14 to fill the entire area of the receiving groove 14. (18) flows along the surface; The result is the shape of the seal 10 shown in FIG. 4 prior to placing the molded body 32 on the mold member 12.

The application nozzles 36 may be aligned in a suitable manner. In the embodiment shown, an alignment perpendicular to the plane of the drawing has been chosen, but if necessary, it can be applied obliquely to the plane of the drawing so that the viscous sealing material 10 can easily flow out of the nozzle.

This embodiment is particularly suitable for rapidly forming the seal 10 without drops. There is no need to provide a special protective gas atmosphere because of the preferred use of a solvent-free sealing material which may be a two-component sealing material.

It is possible to modify the shape of the excess material 24 using the application nozzle 36 in a known manner very similar to the shape of the bearing groove 26 required instead of the excess material 24 of the shape shown. In this case, it is necessary to choose a special type of nozzle depending on the shape of the bearing groove. In essence, however, the displacement of the material needs to be minimal to enable manufacturing at higher speeds.

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Claims (21)

Providing a bearing groove in the cylinder head; Providing a mold member operating with the bearing groove to form a seal; Introducing a sealing material into the mold member to provide a finite excess of material that exceeds the amount of sealing material required to fill the bearing grooves; A method of making a seal in a cylinder head of an automobile quantity, comprising the step of curing under pressure a sealing material contained in a bearing groove and a mold member to form a seal. The method of claim 1 wherein the introducing step comprises compressing the defined excess material into the bearing grooves while in the plastically deformable state prior to curing. The method of claim 1 wherein the introducing step comprises applying a pressure of 1.5 to 6 bar to the sealing material during the introduction. 4. The method of claim 3 wherein the pressure is three bars. The method of claim 1, wherein the introducing step comprises applying a sealing material using a low pressure metering and mixing device, wherein the sealing material is a thermosetting two-component silicone elastomer. 2. The method of claim 1, further comprising heating the sealing material prior to introducing the sealing material into the mold member. 7. The method of claim 6, further comprising heating the cylinder head prior to introducing the sealing material. 8. The method of claim 7, further comprising heating the mold member prior to introducing the sealing material. 7. The method of claim 6, further comprising heating the mold member prior to introducing the sealing material. The method of claim 1 further comprising heating the cylinder head prior to introducing the sealing material. The method of claim 10, further comprising heating the mold member prior to introducing the sealing material. The method of claim 1, further comprising heating the mold member prior to introducing the sealing material. 2. The method of claim 1 wherein the mold member has a low mass and includes a receiving groove and the mold member is reinforced in the receiving groove region. 14. The method of claim 13, further comprising providing a non-sticky surface layer in the receiving groove to facilitate removal of the seal from the mold member. 15. The method of claim 14, wherein the non-sticky surface is made of polytetrafluoro ethylene. The method of claim 1 wherein the sealing material is free of solvent. 17. The method of claim 16, wherein the sealing material is free of ethyl acetate. A press device for applying a seal to a cylinder head of a vehicle motor, wherein the cylinder head includes a bearing groove for accommodating the seal, the press device comprising a limited excess material that exceeds the amount of sealing material required for filling the bearing groove. And a mold member having a receiving groove for receiving, wherein the press device works together to compress the defined excess material into the mold member and the mold member and the bearing groove surround the sealing material to be cured under heating. Press device. 19. The apparatus of claim 18, wherein the mold member is positioned so that the receiving groove faces upward and a sealing material is introduced from above into the receiving groove. 19. The apparatus of claim 18, further comprising a heating device for periodically heating at least one of the cylinder head and the mold member to a preheating temperature and a curing temperature, and further comprising a preheating zone for preheating the cylinder head advanced to the press device. Characterized in that the device. The apparatus of claim 20 wherein the preheating temperature is 60 ° C. and the curing temperature is 150 ° C. 21.