EP2292900A2 - metallic screwed plug - Google Patents

Abstract

An automotive oil sump has a metal drain plug with a threaded outer shank and a head containing a socket hole for the removal/tightening tool. In a process to manufacture the plug (10) a metal blank is cut with a head (12) and a cylindrical truncated pipe (26) with an inner diameter and outer diameter which is less than the finally envisaged dimensions (e, f). The truncated pipe (36) sidewall is then placed under inner pressure and widened.

Description

The invention relates to a screw plug made of metallic material for a fluid line - in particular for an oil line or an oil vessel - with a cylindrical shaft containing an external thread on a ridge plate in which a blind hole polygonal cross-section is centrally provided as a receiving member for a tool according to the preamble of claim 1.

From the EP-A-0 461 344 is a provided with blind hole plastic plug known.

The GB-A-1 274 754 shows a metallic screw plug.

From the JP 57 151246 U a closure screw is known which has a blind hole on a side opposite a drive opening. The production of such a screw is relatively expensive. The known screw has at the head a phase portion in which the external thread expires. The known screw can not be screwed to the plant of the bottom of the head in an internal thread, which can be problems in the production of a tight connection.

Screw plugs of this type are mainly used in motor vehicles and must therefore be produced in large quantities. It has proven to be favorable so far that their production must be carried out in at least three stages of production. To improve this improvement is the object of the invention.

To achieve this object, the teaching of the independent claim; the dependent claims indicate favorable developments. In addition, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention.

According to the invention, the shaft is designed as a pipe stump provided with the external thread, and from the end face of the shank of the screw plug, a blind hole that is coaxial to the usual blind hole of the ridge plate is newly designed. Of particular importance is that at one of the ridge plate achswärts - in one longitudinal incision angle of preferably 30 ° - inclined and widening firstward phase section as a transition to the pipe stub the rohrwärtige foot contour of this phase section at the same time - constructive - inner approach line for this contour radially projecting external thread should be. Otherwise, a diameter of the foot contour of the phase section of 19.5 mm is preferred.

As low it has proven to have the deepest hole of the blind hole of the pipe stump have a inclined from the wall surface to the screw longitudinal axis cross-section; Advantageously, the depth of the wall surface should be about 8 mm, in particular 7.8 mm.

The shape of the closure screw according to the invention also includes that the free pipe edge of the pipe stump at least one - and preferably both sides - one assigned by this edge of the pipe away to the ridge plate inclined phase edge is assigned, the outer phase edge is to pass into the external thread.

In the context of the invention is above all a method for producing this screw plug, in which a blank is produced with a molded onto a ridge plate subsequent cylindrical stump, the inner diameter and outer diameter are formed shorter than the intended, this corresponding diameter of the screw plug; the tube stump of the blank is widened by simultaneously creating pressure on the inner wall surface of its blind hole. According to another feature of the invention, a plunger is driven as a mandrel tool in the blind hole of Rohlingrohrstumpfes and radially widened by this the wall of the pipe stub.

It has proven to be advantageous if the outer surface of the pipe stub is pushed radially beyond the foot contour of the adjoining the ridge plate - cross-sectionally inclined to the axis - phase portion of the blank; the external thread is to be formed in the tube outer surface of the flared tube stub, advantageously in the achswärts of that foot contour of the phase section specific region of the tube stub. This molding is advantageously carried out after the production of the above-described shape of the screw plug by a separate thread rolling process.

However, within the scope of the invention is also a method in the course of which the Au-βenfläche the tube stump is pressed during its expansion against a surrounding mold surface with threaded negative.

Preferably, the method is characterized in that a blank (34) with a cylindrical ridge (36) integrally formed on a ridge plate (12) is produced, whose inner diameter (e ₁ ) and outer diameter (f ₁ ) are formed shorter than the corresponding ones provided Diameter (e, f) of the screw plug (10), and that the tube stub (36) of the blank is expanded to generate pressure on the inner wall surface (19 _a ) of the blind hole (18 _a ).

In development of the invention it is provided that in the blind hole (18 _a ) of the pipe stump (36) of the blank (34) an inner diameter (e ₁ ) cross-sectionally increasing portion (52) of a plunger (50) introduced as a mandrel tool and the pipe stump this / this is radially expanded.

In a further development of the invention, it is provided that the outer surface (38) of the pipe stub (36) is pushed radially beyond the foot contour (25) of a cross-sectionally axially inclined phase section (24) adjoining the ridge plate (12).

In a further development of the invention, it is provided that an outer thread (22) is formed in the tube outer surface (38) of the expanded tube stub (36).

It is preferably provided that the external thread (22) is formed in the region of the pipe stub (36) which is determined axis-wise from the foot contour (25) of the phase section (24).

More preferably, it is provided that the external thread (22) is formed in the outer surface (38) of the pipe stub (36) by way of thread rolling.

In a further development of the invention, it is provided that the outer surface (38) of the tube stub (36) is pressed against an encompassing molding tool.

Of particular importance is the blank used for the process for producing the closure screw; in this connects to the ridge plate a cylindrical pipe stub of an outer diameter and a diameter of the blind hole, whose Dimensions are shorter than those of the outer diameter and the hole diameter of the actual screw plug; The diameter of the blind hole should measure about 12 mm and the outer diameter of the pipe stump about 19 mm, preferably 19.2 mm. The dimensional difference to the final product is compensated by the expansion process.

Preferably, a blank for producing a closure screw (10) is provided, which is characterized in that on the ridge plate (12) of the blank (34) has a cylindrical tube stub (36) of an outer diameter (f ₁ ) and a diameter (e ₁ ) of the Blind hole (18 _a ) connects, whose dimensions are shorter than the outer diameter (f) and hole diameter (s) of the screw plug (10).

In an embodiment of the blank, it is advantageously provided that the outside diameter (f ₁ ) of the tube stub (36) on the blank (34) is shorter than the base diameter (g) of the phase section (24) on the closure screw (10).

It is preferably provided with advantage that the phase section (24) of the blank (34) encloses an angle (w) with the blank longitudinal axis (A), which preferably measures approximately 30 °.

The blank is preferably characterized by a diameter (e ₁ ) of the blind hole (18 _a ) of about 12 mm and an outer diameter (f ₁ ) of the pipe stump (36) of about 19 mm, preferably of 19.2 mm.

The blank is preferably characterized in that the pipe edge (16 _a ) of the pipe stub (36) on both sides in each case one of the pipe edge away inclined phase edge (15 _a , 17 _a ) is assigned.

In a further development of the blank is advantageously provided that the outer phase edge (17 _a ) of that tube stub (36) merges into the cylindrical tube outer surface (38).

Also, it has proved to be favorable to choose the outer diameter of the pipe stub on the blank shorter than the foot diameter of the phase section on the screw plug; the latter - as well as the phase section of the blank - should enclose an angle with the blank longitudinal axis, which preferably measures about 30 °.

According to another feature of the invention, the pipe edge of the pipe stump on both sides is assigned in each case one of the pipe edge inclined away phase edge, wherein the outer phase edge merges into the cylindrical pipe outer surface.

Of inventive importance is also a tool with which the deformation of the blank can be done in a simple manner; According to the invention, a plunger is set as a mandrel tool at one end in a housing and the free end of a relatively movably arranged support or holding head associated with a receptacle for a blank; the axis of which runs in the central axis of the tool or the plunger. It is also beneficial that at the that the support or holding head far end of the sleeve-like housing, a stationary base plate is provided which forms an abutment for her seated plunger. According to the invention, the free end of the plunger partially surrounded by a plunger tube is intended to engage in a central bore of the support or holding head, a printhead of the plunger then projecting axially beyond the mouth edge of the plunger tube. For this purpose, it has proven to be advantageous if this stamp tube at the other end - preferably with a disc base - a stationary stationary sleeve of the tool is seated, which forms a support surface for the stationary sleeve passing through plunger. In order to improve the printing process, a central pressure base can be formed on that base plate, which forms a common abutment for the plunger and the stand sleeve.

Preferably, a tool for producing a closure screw (10) is used, which is characterized in that in a housing (42) a plunger (50) as a mandrel tool at one end and the free end of a relatively movably arranged support or holding head (68) associated with a receptacle for a blank (34), wherein the axis (A) in the central axis (M) of the tool (40) and the plunger extends.

Preferably, it is provided in the tool that the sleeve-like housing (42) at that the support or holding head (68) far end is associated with a stationary base plate (44) which forms an abutment for her seated plunger (50). Further preferably, the tool is provided in that the free end of the partially compressed by a stamping tube (54) plunger (50) engages in a central bore (70) of the support or holding head (68), wherein a printhead (52) of the Plunger axially overhanging the mouth edge (56) of the stamp tube.

Further preferably, it is provided in the tool that the punch tube (54) at the other end, preferably with a Tellerfuß (57), a stationary stationary sleeve (48) of the tool (40) is seated, which forms a support surface for the stationary sleeve passing through plunger (50) ,

In a further development, the tool is characterized by a disc-like centric pressure base (46) of the base plate (44) as an abutment for the plunger (50) and the stationary sleeve (48).

Preferably, it is provided in the tool that the supporting or holding head (68) of a sliding sleeve (60) is seated, which is associated coaxially with the plunger (50) and the stationary sleeve (48).

More preferably, it is provided in the tool that the diameter (q ₁ ) of the pressure base (46) approximately corresponds to the seated diameter of the sliding sleeve (60).

Even more preferably, it is provided in the tool that the sliding sleeve (60) has on a foot section (64 _t ) assigned to the pressure base (46) a head section (64) which is radially widened relative to the latter.

Preferably, it is provided in the tool that the sliding sleeve (60) with the holding head (68) of a guide chuck (80) holding holding and with this relative to the housing (42) is arranged axially movable.

More preferably, the tool is provided that between the base plate (44) and the guide chuck (80) an energy storage device (78) is arranged.

In a further development, the tool is characterized by a profile element (78) made of elastic material as energy storage.

Preferably, it is provided in the tool that the energy storage or the profile element (78) is annularly placed around the pressure base (46) of the base plate (44). Further preferably, it is provided in the tool that the blank (34) seated in the carrying or holding head (68) is pressed onto the print head (52) during its axial movement Pressure stamp (50) is arranged aufpressbar, wherein the diameter thereof is greater than the diameter (e ₁ ) of the blind hole (18 _a ) of the blank.

It is also within the scope of the invention that the carrying or holding head of the tool is seated on a sliding sleeve which is associated coaxially with the pressure ram and the stationary sleeve. The diameter of the pressure base should then correspond approximately to the seated diameter of the sliding sleeve.

The latter has, moreover, on a base portion assigned to the pressure base, a head portion which is radially widened relative to the latter and is intended to be held in a holding manner by the holding head by a guide chuck and arranged to be axially movable relative thereto with respect to the housing.

To support the movement of the base plate and the guide chuck, a force store is arranged according to the invention between these tool parts, in particular a profile element of elastic material. This profile element is preferably placed annularly around the pressure base of the base plate and can be made of strands of material of different cross-sectional shape.

Finally, it has proved to be favorable that the blank sitting in the supporting or holding head blank can be pressed in its axial movement on the print head of the plunger, wherein the diameter of the plunger is greater than the diameter of the blind hole in the blank, i. when inserting the plunger, the blank expands.

Overall, a captivatingly simple method for producing the closure screws mentioned above results.

• Fig. 1: eine skizzenhafte Schrägsicht auf einen erfindungsgemäßen Rohling für eine Verschlussschraube;
• Fig. 2: einen Diametralschnitt durch die Verschlussschraube;
• Fig. 3: eine der Fig. 2 entsprechende Darstellung des Rohlings zur Herstellung der Verschlussschraube;
• Fig. 4: den Längsschnitt durch ein Werkzeug zum Herstellen der Verschlussschraube mit oberhalb eines Pressstempels eingesetztem Rohling vor Beginn des Formvorganges;
• Fig. 5: die der Fig. 4 entsprechende Darstellung des Werkzeuges am Ende des Formvorganges mit entstandener Verschlussschraube;
• Fig. 6: den Längsschnitt durch den Presstempel mit zugeordnetem Rohling.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing; this shows in

• Fig. 1 a sketchy oblique view of a blank according to the invention for a screw plug;
• Fig. 2 : a diametrical section through the screw plug;
• Fig. 3 : one of the Fig. 2 corresponding representation of the blank for the production of the screw plug;
• Fig. 4 : the longitudinal section through a tool for producing the locking screw with blank inserted above a press ram before the beginning of the molding process;
• Fig. 5 : the the Fig. 4 Corresponding representation of the tool at the end of the molding process with a developed screw plug;
• Fig. 6 : the longitudinal section through the ram with associated blank.

A screw plug 10 for a not shown for reasons of clarity oil line or oil tank of a motor vehicle has on a plate-like ridge plate 12 axial height b of 4.5 mm and the diameter d of about 27 mm to the longitudinal axis A of the screw plug 10 axially integrally formed pipe stump 14th of the outer diameter f; the axial height a of the screw plug 10 measures 19 mm, from which a height c of the tube stump 14 of 14.5 mm is calculated.

In the stump 14 a - from his designed as a pipe edge 16 face - blind hole 18 of diameter e of 13.8 mm and the wall depth c of 7.8 mm provided, the lowest 20 of the wall surface 19 of the blind hole 18 for Screw longitudinal axis A out - viewed in cross-section - is centrally inclined, so forms a flat conical surface. Those tube edge 16 accompanies the blind hole 18 towards an inclined phase edge 15th

Such an inclined phase edge 17 also surrounds the pipe edge 16 from the outside and merges into an external thread 22. At the upper edge of the external thread 22, a molded-in, closes to the ridge plate 12 at a cross-sectional angle w of 30 ° (see FIG. Fig. 3 ) conically expanding phase portion 24 axial height i of 2.5 mm. Its randwärtiger foot diameter g measures 19.5 mm. The external thread 22 attaches to the rohrwärtige foot contour 25 of the phase portion 24 and protrudes radially beyond this.

From the surface 13 of the ridge plate 12 is a central blind hole 28 hexagonal cross-section of the diameter z of about 4.8 mm (SW 10) and the wall depth y of 7 mm. Its hole deepest 30 is also centrally inclined from the wall surface 29 to the screw longitudinal axis A, also forming a flat conical surface. In this first blind hole 28 is used to rotate the screw plug 10 a - not reproduced in the drawing - tool used.

For producing the screw plug 10 is a in Fig. 3 illustrated blank 34 made of metal (for example, 19 MnB4) made of - the ridge blind hole 28 containing - ridge plate 12 and a cylindrical tube stub formed thereon 36; while the ridge plate 12 in its and its blind hole 30 dimension (b, d, y, z) corresponds to that of the finished screw 10, the tube stump 36 of the blank 34 is designed differently to the pipe stump 14. The pipe outer surface 38 is here at the end of the ridge plate 12 far end - also the final dimensions g, w having - inclined phase portion 24 at; the diameter f1 of its cylindrical contour is 19.2 mm, that is, 1.77 mm shorter than the outer diameter f on the finished screw plug 10. The diameter e1 of the blind hole 34 present, adjoining the inner phase edge 15a of the tube edge 16a blind hole 18a measures 12 mm, that is 1.8 mm shorter than the diameter e of the finished screw plug 10. The outer phase edge is denoted here by 17a.

For the production of the screw plug 10 from the blank 34 whose tube stump 36 is expanded approximately by driving a mandrel into the blind hole 18a and pressure generation on the latter wall surface 19a accurate to the tube stump 14, which easily the external thread 22 is able to be formed.

A tool 40 for a preferred way of producing the screw plug 10 is the 4 to 6 refer to. Coaxial with its central axis M is a cylindrical tool housing 42 of the exemplary outer diameter q of 120 mm, a base plate 44 with centrally formed pressure base 46 of a diameter q1 of 60 mm and a height n1 of 21.5 mm and associated with a radial stepped bore 45.

On the pressure base 46 sits a stand sleeve 48 of length n2 of about 47 mm with an axial bore 47, which offers a cross-sectionally expanded end portion 47t of the diameter t1 of 16 mm. This axial bore 47, 47t receives a plunger 50 as a mandrel tool, above the stationary sleeve 48, a plunger tube 54 of length n of nearly 60 mm from a pipe section 55 with this one end molded cup base 57 of diameter t3 of about 40 mm embraces; the outer pipe diameter t2 measures 21 mm, the inner diameter t of the pipe interior 58 about 14 mm. The latter continues downwards through those axial bores 47 of the stationary sleeve 48. In addition to the axial bore 47, 47t and to her at a radial distance in the stationary sleeve 48 is still an axially parallel bore 49 of narrower diameter, which is aligned with a corresponding bore 49a in the base plate 44.

On the stationary sleeve 46 of the diameter q2, a sliding sleeve 60 of a height of about twice the length mentioned n2 is attached externally; the lower edge 62 sits in Fig. 5 the centric pressure base 46 of the base plate 44. The cylindrical outer surface of the lower half or foot portion 64t of the sliding sleeve 60 continues the outer surface of the pressure base 46 and defines a cylindrical cavity 63. In a length n2 of the stationary sleeve 48 approximately corresponding distance to that lower edge 62 starts a wider head portion 64 of the sliding sleeve 60, which carries on its ridge end 66 a holding head 68 - upwardly tapered cross-section - with a central bore 70; this takes up the upper end of the tube section 55 of the punch tube 54, whose outer diameter t2 determines the diameter of the bore 70. The height n3 of the holding head 68 is slightly shorter than the length n2 of the stationary sleeve 48.

Between the outer tool housing 42 on the one hand and the sliding sleeve 60 and the holding head 68 on the other hand extends a space filling, also sleeve-like guide chuck 80. This encloses the sliding sleeve 60 and the holding head 64 conclusive and can be moved together with these inner parts together as a unit in the tool housing 42 become. In the area of that cavity 63, it is provided with a thread 81 for a threaded sleeve 84 which extends in that cavity 63.

43 denotes a guide edge of the housing 42 directed towards the center axis M, 41 a radial guide member which engages in an axially parallel guide recess 82 of the guide chuck 80.

The ridge portion of the bore 70 is cross-sectionally adapted to the structural design of the screw plug 10, ie the diameter of the bore 70 corresponds with a small clearance - the outer diameter f of the tube stump 14 of the screw plug 10 and extends approximately in one of the axial height b of the ridge plate 12th corresponding distance from the end face 76 of the holding head 68 of a conical annular plane 72 of the bore wall 71 - corresponding to the inclined phase portions 24 of the screw plug 10 - up to a step 74, according to FIG Fig. 4 the ridge plate 12 of the blank 34 is placed. The circumference of the pipe stub 36 extends in a ring distance to the bore wall 71 of the central bore 70th

During this insertion process is the phase edge 15a of the blank 34 - at a distance from the mouth edge 56 of the tube section 55 - on the corresponding inwardly inclined ridge or phase edge 51 of the endwärtigen section or print head 52 of the plunger 50, which corresponds to the mouth edge 56 of the punch tube 54 surmounted. The diameter of this Firstrandes 51 corresponds to the diameter e of the blind hole 18 of the screw plug 10, that is greater than the corresponding diameter e1 on the blank 34th

For the printing or molding process, the guide chuck 80 is lowered within the housing 42 in the direction x to the base plate 44 against a indicated at 78 profile ring approximately circular cross section of elastic material, ie the distance s between them is reduced, the punch or printhead 52 of the stationary plunger 50 penetrates into the blind hole 18 a of the blank 34 and the tube stub 36 expands until the outer surface 38 of the bore wall 71 of the bore 70 abuts. The dimension k of here 7 mm of the pressure path is in Fig. 5 recognizable. Those arranged between the base plate 44 and guide plate 80 profile ring 78 may be otherwise configured cross-section otherwise than in Fig. 5 outlined; optionally it is designed as a hollow profile.

After the molding process, the not quite finished screw plug 10 _{r is} removed from the holding head 68 and its expanded pipe stub 36 equipped with the external thread 22; then the screw plug 10 is ready for use.

Claims (9)

Closure screw made of metallic material for a fluid line, in particular for an oil line or an oil vessel, with an external thread (22) containing cylindrical shaft (36) on a ridge plate (12), in which centric a blind hole (28) polygonal cross-section as a receiving member for a Tool is provided, wherein the shank (36) as with the external thread (22) provided with a stub pipe (14) and from the end face (16) of the shaft to a blind hole (28) of the ridge plate (12) coaxial blind hole (18) goes out , and wherein a phase section (24) which has a tubular foot contour (25) and is inclined in the axial direction by the ridge plate (12) is provided as a transition to the shaft (36),
characterized,
in that the tubular foot contour (25) of the phase section is an inner starting line for the external thread (22) projecting radially beyond this contour. Closure screw according to claim 1, characterized in that the firstwardly widening phase section (24) of the closure screw (10) with the longitudinal axis of the screw (A) includes an angle (w) in the longitudinal direction, which preferably measures about 30 °. Closure screw according to claim 1 or 2, characterized by a diameter (g) of the foot contour (25) of the phase portion (24) of 19.5 mm. Closure screw according to one of claims 1 to 3, characterized in that the hole deepest (20) of the blind hole (18) of the tube stump (14) has a of its wall surface (19) to the screw longitudinal axis (A) inclined cross-section. Closure screw according to claim 4, characterized by a depth (c) of the wall surface (19) of about 8 mm, in particular of 7.8 mm. Closure screw according to one of claims 1 to 5, characterized in that the tube edge (16) is associated with at least one of this away firstwardly inclined phase edge (15 or 17). Closing screw according to claim 6, characterized in that the pipe edge (16) on both sides in each case one away from the pipe edge firstwardly inclined phase edge (15, 17) is associated. Closure screw according to claim 7, characterized in that the outer phase edge (17) merges into the external thread (22). Use of a closure screw according to one of the preceding claims with a blind hole (18) emanating from the end face (16) of the shank as a screw plug for an oil line or an oil vessel.

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