EP3181259A1 - Method of manufacturing a housing for a drill motor - Google Patents

Abstract

The invention relates to a method for producing a housing for a drilling motor, comprising a tubular steel jacket (1) with a coiled inner surface (2) and a lining (3) made of a sliding alloy following the coiled inner surface (2) for receiving (4). a coiled rotor, wherein a jacket tube (5) is forged over a mandrel. In order to provide advantageous manufacturing conditions, it is proposed that the lining (3) in the form of a prefabricated lining pipe (6) is inserted into the jacket pipe (5) and that the jacket pipe (5) and the lining pipe (6) together over the coiled inner surface (8) of the housing-defining mandrel for a composite body (7) forming housing are forged.

Description

The invention relates to a method for producing a housing for a drilling motor, comprising a tubular steel jacket with a coiled inner surface and a coiled inner lining of a sliding alloy for receiving a coiled rotor, wherein a jacket tube is forged over a mandrel ,

In order to be able to provide the casing of a housing for a drilling motor with a uniformly thick lining for the coiled inner surface for accommodating a coiled rotor, it is known ( WO 1999/031389 ) starting from a jacket tube which is made with a coiled inner surface for the lining predetermining form by rolling or forging over a correspondingly shaped mandrel, so that the liner must be applied only in a predetermined thickness on the coiled inner surface of the prefabricated casing tube, to get the housing for the drill motor. A disadvantage, however, is that by the subsequent application of the liner of an elastomeric, thermoplastic, ceramic or metallic material on the coiled inner surface of the jacket tube made of steel depending on the respectively selected taking into account the material of the lining application method, such as galvanic or electrolytic deposition, casting , Firing, plasma spraying or thermofixing, the adhesion of the lining to the profiled casing pipe often can not meet higher requirements. In addition, it must be expected for the profiling of the lining with a comparatively high manufacturing tolerance, which can be taken in linings made of an elastomeric material in purchasing, however, can lead to a reworking in metallic linings, if higher demands are placed on the manufacturing tolerances.

For producing an at least two-layer metallic composite pipe with low manufacturing tolerances, it is also known (US Pat. RU 2171164 C1 ), in an outer layer forming a jacket tube to introduce an inner layer of a wound at least one layer to a tubular body sheet metal strip and to connect the jacket tube with the tubular inner layer by a cold forging over a mandrel to a composite body with the advantage that the cold deformation not only the strength of the composite increased, but also the manufacturing tolerance can be kept small. In addition, because of the cylindrical inner surface of the composite pipe, a uniform thickness of the metallic inner layer over the pipe length can be ensured. However, this method is not suitable for the production of hollow workpieces with a coiled inner surface.

The invention is therefore based on the object, a method for producing a housing for a drilling motor in such a way that simple manufacturing conditions are ensured, which allow low manufacturing tolerances and bring a high level of reliability for the housing with it.

Starting from a method of the type described, the invention solves the problem by the fact that the liner is inserted in the form of a prefabricated liner pipe in the jacket tube and that the jacket tube and the liner tube together on the coiled inner surface of the housing-defining mandrel forming a composite body Housing forged.

The invention is based on the finding that in linings made of a sliding alloy, this sliding alloy does not have to be applied in a predetermined layer thickness on the pre-profiled inner surface of the jacket tube to receive one of the coiled inner surface of the jacket tube following lining of uniform thickness, but that the conditions for a advantageous, adapted to the requirements of such a lining production of the composite body of the casing tube and the liner can be advantageously specified when the liner is inserted in the form of a prefabricated liner pipe in the jacket tube, then forging the jacket tube together with the liner tube over the coiled inner surface of the housing-defining mandrel to the composite body. Due to the common cold deformation of the jacket tube and the lining tube by a cold forging over a correspondingly profiled mandrel on the one hand, the metallurgical properties of the composite body are improved and on the other hand ensures the required dimensional accuracy for the coiled inner surface of the housing.

The cold forging of the jacket tube and the lining tube to the finished composite body is determined by the degree of deformation permitted for this purpose. If a higher degree of deformation for the casing tube is required for producing a housing for a drilling motor due to the coiled inner surface, the casing tube and the inserted liner tube can be first connected by a thermoforming a mandrel to a composite body before the composite body by cold forging over the coiled inner surface defining mandrel is molded to the housing. The hot deformation allows the required degree of deformation to approach the coiled inner shape of the housing and further ensures intimate bonding between the steel jacket tube and the liner of a sliding alloy so that subsequent cold working by forging over a mandrel defining the coiled inner surface of the housing the housing can be completed with respect to the profile shape of the inner surface without Nachbearbeitungsbedarf.

However, in order to realize higher degrees of deformation with simple means, it is also possible for the jacket tube and the lining tube to be preformed before the common forging in approximation to the coiled inner shape of the housing. In this case, by cold forging the nested shell and lining tubes, the final shape can be produced, because yes parked on the final form preforms of Casing tube and the lining tube only require a relatively low forging deformation. For the preparation of the preforming of the casing tube and the lining tube, these tubes can be produced by hot forging over a mandrel, which is not mandatory, because it is important for the housing production only to introduce the preformed liner tube in the correspondingly preformed jacket tube and then the two tube together by cold forging to form a composite body.

Fig. 1

ein Gehäuse für einen Bohrmotor ausschnittsweise in einem Längsschnitt,

Fig. 2

das Gehäuse nach Fig. 1 in einem Schnitt nach der Linie II-II der Fig. 1,

Fig. 3

ein einen Verbundkörper mit einer Auskleidung bildendes Mantelrohr zur Herstellung eines Gehäuses nach Fig. 1 in einem Längsschnitt vor dem Kaltschmieden,

Fig. 4

einen Schnitt nach der Linie IV-IV der Fig. 3,

Fig. 5

ein vorgeformtes Mantelrohr zur Herstellung eines Gehäuses nach Fig. 1 in einem Längsschnitt,

Fig. 6

einen Schnitt nach der Linie VI-VI der Fig. 5,

Fig. 7

ein vorgeformtes Auskleidungsrohr für ein Mantelrohr gemäß den Fig. 5 und 6 in einem Längsschnitt,

Fig. 8

einen Schnitt nach der Linie VIII-VIII der Fig. 7,

Fig. 9

das Mantelrohr nach der Fig. 5 mit dem Auskleidungsrohr gemäß der Fig. 7 in einem Längsschnitt und

Fig. 10

einen Schnitt nach der Linie X-X der Fig. 9.

Reference to the drawing, the inventive method is explained in detail.
Show it

Fig. 1

a housing for a drill motor in sections in a longitudinal section,

Fig. 2

the housing after Fig. 1 in a section along the line II-II of Fig. 1 .

Fig. 3

a jacket tube forming a composite body with a liner for producing a housing Fig. 1 in a longitudinal section before cold forging,

Fig. 4

a section along the line IV-IV of Fig. 3 .

Fig. 5

a preformed jacket tube for producing a housing according to Fig. 1 in a longitudinal section,

Fig. 6

a section along the line VI-VI of Fig. 5 .

Fig. 7

a preformed liner pipe for a casing pipe according to FIGS. 5 and 6 in a longitudinal section,

Fig. 8

a section along the line VIII-VIII of Fig. 7 .

Fig. 9

the casing after the Fig. 5 with the lining pipe according to the Fig. 7 in a longitudinal section and

Fig. 10

a section along the line XX the Fig. 9 ,

The housing for a drilling motor has according to the schematic illustration of the Fig. 1 and 2 a steel shell 1 with a coiled inner surface 2 and a lining 3, which follows the coiled inner surface 2 of the shell 1 and forms a coiled receptacle 4 for a coiled rotor of the drill motor. For the production of such a housing can according to the Fig. 4 are assumed by a dash-dotted line indicated steel jacket tube 5, in which a lining tube 6 is inserted from a sliding alloy to connect the jacket tube 5 together with the inserted liner tube 6 by a hot forging to a composite body 7 having an approximated to the housing shape preform. Due to the hot forging on a mandrel with a correspondingly coiled shape of the preform the required for the deformation of the casing tube 5 to the preform deformation rate can be easily ensured, resulting in an advantageous metallic connection between the jacket tube 5 and the lining tube 6. This intimate bond between the jacket tube 5 and the lining tube 6 ensures for the subsequent cold forging that no dislocation of the lining affecting local displacement of the lining tube 6 relative to the jacket tube 5 may occur. After the cold forging of the preformed by a hot forging composite body 7 via a coiled inner surface of the housing-defining mandrel is thus a housing according to the Fig. 1 and 2 received, which requires no reworking with respect to the recording 4 for the rotor.

According to the Fig. 5 to 10 is used to manufacture a housing according to Fig. 1 and 2 Starting from a preformed casing 5, the approximate to the coiled inner surface 2 of the shell 1, for example, by a hot forging of a in the Fig. 6 dash-dotted lines indicated, a circular ring cross section having jacket tube 5 has been prepared and forms a coiled inner surface 8. The lining pipe 6 provided for the lining 3 is also preformed in approximation to the coiled inner surface 2 of the jacket 1, as shown in FIGS FIGS. 7 and 8 is shown. The preformed liner tube 6 is in accordance with FIGS. 9 and 10 introduced into the preformed jacket tube 5, to then together with the jacket tube 5 by a cold forging over a mandrel to the composite body 1 of the housing according to the Fig. 1 and 2 to be transformed.

Claims (3)

A method of manufacturing a casing for a drilling motor comprising a tubular steel casing (1) having a coiled inner surface (2) and a lining (3) of a sliding alloy following the coiled inner surface (2) for receiving (4) a coiled rotor wherein a jacket tube (5) is forged over a mandrel, characterized in that the lining (3) in the form of a prefabricated lining tube (6) is inserted into the jacket tube (5) and that the jacket tube (5) and the lining tube (6 ) are jointly forged over the coiled inner surface (8) of the housing-defining mandrel for a composite body (7) forming housing. A method according to claim 1, characterized in that the jacket tube (5) and the inserted liner tube (6) are first connected by a thermoforming through a mandrel to a composite body (7) before the composite body (7) by a cold forging over the coiled Inner surface defining mandrel is molded to the housing. A method according to claim 1 or 2, characterized in that the jacket tube (5) and the lining tube (6) are preformed prior to the common forging in approximation to the coiled inner shape of the housing.

Images