Cartridge case comprising a case jacket and a base piece fastened thereto by cold-forming

Abstract

The invention relates to a cartridge case for ammunition, in particular having a caliber of less than 20 mm, in particular of less than 13 mm, comprising a rotationally symmetrical case jacket and a base piece, fastened to the case jacket by means of cold-forming, for accommodating a primer, wherein the material of the base piece has a greater modulus of elasticity than the material of the case jacket.

Description

[0001] CARTRIDGE CASING COMPRISING A CASING SKIRT AND A BASE PIECE ATTACHED TO IT BY COLD FORGING

[0002] The present invention relates to a cartridge case for ammunition, in particular with a caliber of less than 20 mm, in particular less than 13 mm, comprising a rotationally symmetrical case shell and a cold-formed base piece for receiving a primer cap. Furthermore, the present invention relates to a method for producing such a cartridge case.

[0003] Cartridge cases are generally known and can be constructed in one or more parts. Cartridge cases are generally divided into a base piece facing the primer cap and a case jacket for receiving a projectile. Cartridge cases of this type are known, for example, from DE 10 2021 124 431 Ä1 and DE 10 2020 124 559 Ä1.

[0004] During the deep drawing of the case jacket, the greatest degree of deformation occurs in the area of ​​the open case mouth, which serves to receive the projectile. This is where the greatest hardening occurs. However, material hardening in this area is undesirable, particularly because it has a detrimental effect on the subsequent process step of inserting the projectile. Annealing processes are used to soften the material bonded there. This procedure is laborious and costly.

[0005] Furthermore, it was recognized that when the base piece and the sleeve are joined together, which is done according to the aforementioned prior art methods by pressing the base piece from the outside inward onto the sleeve, which is thus also compressed inward, both components spring back slightly outward due to the elasticity of the materials of the base piece and sleeve, which can lead to a reduction in the holding force between the base piece and sleeve. This can create a certain amount of play, which allows for relative rotation between the base piece and sleeve.

[0006] Finally, the inventors of the present invention discovered that, in both single-piece and multi-piece cartridge cases, the primer cap can be pushed out of the bore in the base during firing of the ammunition. This loosening and detachment of the primer cap can lead to malfunctions of the weapon.

[0007] An object of the present invention is to overcome the disadvantages of the prior art, in particular to provide a cartridge case in which relative movements between the base piece and the case jacket are more reliably avoided.

[0008] The problem is solved by the subject matter of the independent claims.

[0009] According to this, a multi-part cartridge case is provided, in particular with a calibre of less than 20 mm, in particular less than 13 mm.

[0010] Ammunition, also known as a cartridge, typically consists of the following components: a multi-part cartridge case; a primer for igniting the propellant; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases typically comprise at least one base piece facing the primer or accommodating the primer, and a separately manufactured case jacket that is firmly connected to the base piece and accommodates the projectile.

[0011] The cartridge case according to the invention comprises a rotationally symmetrical case jacket for receiving a projectile and a base piece fastened thereto by cold forming for receiving a primer cap.

[0012] The case jacket can comprise a substantially cylindrical case section and a fastening section for connection to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which is reduced in cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be punched or stamped out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0013] According to one aspect of the present invention, the material of the base piece has a higher modulus of elasticity than the material of the sleeve shell. This brings significant advantages because when the base piece and sleeve shell are joined, the base piece is pressed from the outside inwards onto the sleeve shell, which is thus also compressed inwards. After the tool, in particular the pressing tool, is removed, both joining partners spring back slightly outwards due to the elasticity of the materials. According to the invention, the springing of the two joining partners after the pressing tool is removed is thus utilized to reinforce the clamping force exerted on each other by the base piece and sleeve shell. With the materials selected in this way, it is ensured that the springback of the sleeve shell is greater than the corresponding springback of the base piece, so that additional preload can be built up between the base piece and sleeve shell.This eliminates the prior art problem of a certain amount of play between the base piece and the sleeve shell. Regarding the cold forming of the connection between the base piece and the sleeve shell, reference is made to the relevant explanations in DE 10 2020 124 559 A1, the contents of which are incorporated herein by reference.

[0014] In an exemplary embodiment of the cartridge case according to the invention, the modulus of elasticity of the base material is at least 50%, in particular at least 100%, 150%, or at least 200%, greater than the modulus of elasticity of the case jacket material. This ensures even more reliable relative movement between the base and the case jacket.

[0015] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a cartridge case for ammunition is provided, in particular with a caliber of less than 20 mm, in particular of less than 13 mm.

[0016] Ammunition, also known as a cartridge, typically consists of the following components: a multi-part cartridge case; a primer for igniting the propellant; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases typically comprise at least one base piece facing the primer or accommodating the primer, and a separately manufactured case jacket that is firmly connected to the base piece and accommodates the projectile.

[0017] The cartridge case according to the invention comprises a rotationally symmetrical case jacket for receiving a projectile and a base piece for receiving a primer cap.

[0018] The case jacket can comprise a substantially cylindrical case section and a fastening section for connection to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which is reduced in cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be punched or stamped out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0019] According to a further aspect of the invention, the base piece is fastened to the sleeve shell by cold forming in such a way that the sleeve shell is elastically deformed. According to the invention, the sleeve shell exerts an elastic deformation restoring force on the base piece resulting from the cold forming, in particular in order to reinforce a holding force or adhesion between the sleeve shell and base piece. The cold-forming joining of the base piece and sleeve shell can be achieved by cold-forming the base piece onto the sleeve shell and, as a result of the pressing, elastically deforming the sleeve shell at least in sections. This results in an elastic deformation restoring force oriented counter to the deformation movement, which prestresses the sleeve shell towards the base piece. This reinforces the attachment of the sleeve shell and base piece to one another.

[0020] In an exemplary embodiment of the cartridge case according to the invention, the base piece is elastically deformed during cold forming, wherein an elastic deformation recovery force of the base piece directed counter to the deformation is smaller than an elastic deformation recovery force of the case jacket directed counter to the deformation. In other words, the deformation recovery force of the case jacket is greater than that of the base piece. In this respect, a prestress of the case jacket against the base piece can be generated, which can further strengthen their mutual attachment. The inventors of the present invention have identified that the elastic deformation of the joining partners associated with the cold-forming joining can be exploited to exert a holding force on each other.

[0021] According to an exemplary embodiment of the cartridge case according to the invention, the deformation recovery path of the case jacket is at least 50%, in particular at least 100%, 150%, or at least 200%, greater than the deformation recovery path of the base piece. This ensures even more reliable relative movement between the base piece and the case jacket.

[0022] In a further exemplary embodiment of the present invention, a fastening interface between the base piece and the sleeve shell is at least partially, in particular completely, free from thermal post-treatment. This allows a costly and time-consuming manufacturing step to be avoided. According to the present invention, softening of the joining partners in the area of ​​the joining surfaces at the fastening interface is no longer necessary in order to reliably fasten them to one another and / or to reliably ensure the function of the components.

[0023] In a further exemplary embodiment of the cartridge case according to the invention, the base piece has a case jacket joining area for connecting to the case jacket and a receptacle for a primer cap facing away from the case jacket. The case jacket joining area can be subjected to a heat treatment, in particular at a temperature exceeding the recrystallization temperature. Furthermore, the primer cap receptacle can be free of heat treatment. For example, it may be necessary to perform local post-heat treatments in order to make a corresponding section of the joining partners more functional, in particular with regard to the respective requirements to be met by the joining partner.Thermal post-treatment of the primer holder has been identified as disadvantageous in that when the ammunition is fired, the primer may become loose within the primer holder if the material of the primer holder is not sufficiently capable of reliably withstanding the high pressures during the firing of ammunition.

[0024] According to an exemplary embodiment of the present invention, the base piece can be subjected to a temperature treatment, in particular heat-treated, at least in sections, in particular completely. For example, the base piece is hardened to improve springback after firing. For example, the heat treatment can be carried out by means of vacuum hardening or case hardening, for example by adding plastic. The base piece can be hardened at least in sections, in particular completely, to a hardness of 400 HV10 to 600 HV10, in particular from 450 HV10 to 580 HV10 or in the range from 480 HV10 to 540 HV10. The specified hardness for the base piece has proven particularly suitable in view of the various requirements.A base piece with the specified hardness thus exhibits sufficiently good formability, especially for joining. The higher hardness, namely strength, results in greater springback, which manifests itself as elastic expansion after firing. This can prevent the cartridge case from jamming in the firearm barrel.

[0025] According to a further exemplary embodiment of the present invention, the case jacket joining area has a lower hardness than the primer receptacle, in particular by less than 10%, less than 20%, or less than 30%. This allows the two functions of the base piece to be particularly effectively accommodated: first, the primer is reliably held in the primer receptacle without causing the primer to loosen, and second, the case jacket joining area is pretreated in such a way that the cold-forming joining with the case jacket can take place as effectively as possible.

[0026] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a method is provided for producing a cartridge case for ammunition, in particular with a caliber of less than 20 mm, in particular of less than 13 mm, which is designed in particular according to one of the preceding aspects or exemplary embodiments.

[0027] Ammunition, also known as a cartridge, typically consists of the following components: a multi-part cartridge case; a primer for igniting the propellant; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases typically comprise at least one base piece facing the primer or accommodating the primer, and a separately manufactured case jacket that is firmly connected to the base piece and accommodates the projectile.

[0028] According to the method according to the invention, a base piece and a sleeve shell are fastened together by cold forming, with elastic deformation of at least the sleeve shell. Furthermore, the elastically deformed sleeve shell exerts an elastic deformation recovery force on the base piece resulting from the cold forming.

[0029] According to the invention, the sleeve shell exerts an elastic deformation restoring force on the base piece resulting from the cold forming process, in particular to reinforce the holding force or adhesion between the sleeve shell and base piece. The cold-forming joining of the base piece and sleeve shell can be achieved by cold-forming the base piece onto the sleeve shell, and the pressing process elastically deforms the sleeve shell, at least in sections. This results in an elastic deformation restoring force oriented counter to the deformation movement, which prestresses the sleeve shell toward the base piece. This strengthens the bond between the sleeve shell and base piece.

[0030] In an exemplary embodiment of the method according to the invention, the base piece is thermally post-processed, particularly before or during joining with the sleeve shell, in a sleeve shell joining area for connection to the sleeve shell. It has been found that the joining interface between the sleeve shell and the base piece can be pre-treated by thermal treatment before or during joining to improve the joining quality.

[0031] In a further exemplary embodiment of the method according to the invention, the method is designed to produce a cartridge case according to the invention.

[0032] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a case jacket is provided for receiving a projectile and for connecting to a base piece for receiving a primer cap for a multi-part cartridge case, in particular with a caliber of less than 20 mm, in particular less than 13 mm.

[0033] Ammunition, also known as a cartridge, typically consists of the following components: a multi-part cartridge case; a primer for igniting the propellant; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases typically comprise at least one base piece facing the primer or accommodating the primer, and a separately manufactured case jacket that is firmly connected to the base piece and accommodates the projectile.

[0034] The case jacket according to the invention comprises a substantially cylindrical case section and a fastening section for connection to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which is reduced in cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be perforated or punched out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0035] According to one aspect of the present invention, the fastening section is open at an end facing away from the sleeve section and is substantially hourglass-shaped. Alternatively or additionally, the fastening section has a support shoulder adjoining the sleeve section, in particular a conically tapered support shoulder, and an adjoining, in particular a conically widening undercut leg. Because the sleeve shell is open on both sides, it can be formed during production to form the final desired shape with less effort than before. The combination of support shoulder and undercut leg allows the connection to the base piece to be achieved in a simple manner from a manufacturing perspective.The joining of the base piece and the sleeve shell can be carried out according to DE 10 20220 124 559 A1 in that the base piece is plastically deformed for connection to the fastening section of the sleeve shell and / or has bending wings designed according to the fastening section, which on the one hand serve as a support for the support shoulder and on the other hand are designed to engage with the undercut leg.

[0036] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a case jacket is provided for receiving a projectile and for connecting to a base piece for receiving a primer cap for a multi-part cartridge case, in particular with a caliber of less than 20 mm, in particular of less than 13 mm.

[0037] The case jacket according to the invention comprises a substantially cylindrical case section and a fastening section with a reduced cross-section for connection to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which is reduced in cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be perforated or punched out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0038] According to a further aspect of the invention, the case jacket has a maximum hardness in the region of the attachment section. Thus, at the end of the case facing the base, a characteristic hardness gradient is realized within the material of the case jacket, particularly due to the deep-drawing process, which is functionally very well adapted to the operation of the ammunition. This is because the deep-drawn case jacket is provided with a particularly high hardness at the end closest to the base and significantly softer in the middle or at the projectile end of the case jacket. This improves the bracing of the base to the case jacket and better withstands the high internal pressures during firing.In addition, evasive deformation occurs in the softer central region of the case jacket, which relieves stress in the joint section between the case jacket and the base, which is particularly realized with a positive and / or force-locking connection. A further advantage is that, due to the lower hardness, post-treatment measures such as heat treatments, especially annealing processes, can be omitted in the area of ​​the bullet-side end of the case jacket to soften the material resulting from the hardening during forming. This simplifies the production of the case jacket and makes it more cost-effective.

[0039] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a case jacket is provided for receiving a projectile and for connecting to a base piece for receiving a primer cap for a multi-part cartridge case, in particular with a caliber of less than 20 mm, in particular of less than 13 mm.

[0040] The case jacket according to the invention comprises a substantially cylindrical case section with an open mouth section, also called the case mouth, for receiving a projectile, and a fastening section with a reduced cross-section for connecting to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which has a reduced cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be perforated or punched out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0041] According to a further aspect of the invention, the ratio of the hardness of the mouth section to the attachment section is less than 1.0, in particular less than 0.8. During deep drawing of the case jacket, the greatest degree of deformation occurs in the area of ​​the open case mouth, as a result of which the greatest hardening occurs there. The open case mouth area is normally used to insert and receive the projectile. However, annealing processes are currently used for this purpose in order to soften the hardened material again. This procedure is cumbersome and expensive. To avoid this annealing process, one idea of ​​the present invention is to cut off the hardened case mouth area and use the remaining end to connect to the base piece. The normally closed area of ​​the deep-drawn case, which is further processed into the case jacket, is converted to receive the projectile.Since the least increase in hardness occurs in this area during forming or deep drawing, a subsequent annealing process can be omitted.

[0042] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a case jacket is provided for receiving a projectile and for connecting to a base piece for receiving a primer cap for a multi-part cartridge case, in particular with a caliber of less than 20 mm, in particular of less than 13 mm.

[0043] The case jacket according to the invention comprises a substantially cylindrical case section and a fastening section with a reduced cross-section for connection to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which is reduced in cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be perforated or punched out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0044] According to a further aspect of the invention, an annular end face of the sleeve shell facing the base piece, i.e., the fastening section, is produced by cutting to length. The idea is to separate the area of ​​the sleeve shell that has hardened during forming, in particular deep drawing, in order to eliminate the need for post-treatment measures such as heat treatments, in particular annealing processes. This simplifies and reduces the cost of manufacturing the sleeve shell.

[0045] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a case jacket is provided for receiving a projectile and for connecting to a base piece for receiving a primer cap for a multi-part cartridge case, in particular with a caliber of less than 20 mm, in particular less than 13 mm. The case jacket according to the invention comprises a substantially cylindrical case section and a case mouth with a reduced cross-section, facing away from the base piece, for receiving the projectile. The case section and the case mouth can be made from one piece. For example, the case jacket is produced by forming, in particular deep drawing.Furthermore, the sleeve shell can have a fastening section opposite the base piece, which is reduced in cross-section compared to the purely cylindrical section and is designed for connection to the base piece. The fastening section can be substantially open. In other words, a base of the sleeve shell can be perforated or punched out, so that an end of the sleeve shell facing the base piece is formed by an annular end face of the fastening section.

[0046] According to a further aspect of the invention, the sleeve mouth is produced by cold forming and is free from any subsequent thermal treatment, in particular a gluing process. Thus, the sleeve shell can be manufactured more cost-effectively and / or with fewer production facilities.

[0047] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a base piece is provided for a cartridge case, in particular a multi-part cartridge case for ammunition, in particular with a caliber of less than 20 mm, in particular less than 13 mm, less than 9 mm, and more than 6 mm, in particular 6.8 mm. The base piece serves, among other things, to accommodate a primer cap.

[0048] Ammunition, also referred to as a cartridge, typically consists of the following components: a multi-part cartridge case, for example; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases typically comprise at least one base piece facing the primer or receiving the primer, and a separately manufactured case jacket that receives the projectile and is firmly connected to the base piece. According to one aspect of the present invention, the material of the base piece is selected from the list including structural steel with a carbon content of less than 0.15%, case-hardening steel with a carbon content of less than 0.25%, heat-treatable steel with a carbon content of 0.2% to 0.65%, and a heat-treatable aluminum alloy.It was discovered that few materials are suitable for meeting the essentially complementary requirements of using the strongest possible material to withstand the high pressures during ammunition firing, while also exhibiting the best possible formability so that the base piece is both easy to manufacture and can be reliably joined to the case jacket. Cold forming processes such as deep drawing and / or pressing are generally used for this purpose. The identified materials, particularly those with the preferred carbon content in steel materials, have proven particularly advantageous with regard to the objective underlying the present invention of preventing the primer cap from loosening.

[0049] Preferred embodiments are specified in the subclaims.

[0050] In the following, further properties, features and advantages of the invention will become clear by describing preferred embodiments of the invention with reference to the accompanying exemplary drawings, in which:

[0051] Figure 1 is a perspective view of an exemplary embodiment of a cartridge case according to the invention;

[0052] Figure 2 is a sectional view of the cartridge case of Figure 1;

[0053] Figures 3a-3c show schematic diagrams of different manufacturing stages of an exemplary embodiment of a cartridge case according to the invention;

[0054] Figures 4a-4d are schematic diagrams of different manufacturing stages of an exemplary embodiment of a sleeve shell according to the invention by means of an exemplary embodiment of a manufacturing plant according to the invention; and

[0055] Figure 5 shows a sectional view of another exemplary embodiment of a cartridge case according to the invention. In the following description of exemplary embodiments of the present invention, a cartridge case for ammunition according to the invention is generally designated by reference numeral 1. Basically, a cartridge case 1 according to the invention comprises the following main components: a rotationally shaped case shell 3; and a rotationally shaped base piece 5 with a central recess 7. The case shell 3 is partially received in the central recess 7.

[0056] With reference to Figures 1 and 2, an exemplary embodiment of a cartridge case 1 according to the invention is described in more detail. The case jacket 3 is generally made of metal and has a substantially constant wall thickness along its longitudinal extent. The case jacket comprises a hollow, upwardly open cylindrical section 9, also called a cylindrical case section, and an adjoining neck section 11, which tapers in cross-section relative to the cylindrical section 9 and is designed for coupling to the base piece 5 and is therefore also referred to as a fastening section. The case jacket 3, in particular the cylindrical section 9, is open on a side 13 facing away from the base piece 5.

[0057] The neck section 11 comprises a support shoulder 15 which is inclined with respect to the central axis of rotation M in the direction of the base piece 5 and extends in the radial direction up to a transition 17 which forms the radially innermost point. The support shoulder tapers conically against the weft direction up to the transition 17. Starting from the transition 17, the cross-section of the neck section 11 widens to form an undercut leg 19. The undercut leg 19 widens conically against the weft direction up to a base 23 of the neck section. The base 23 is completely open and is essentially formed by an end face 21 forming a ring. As can be seen in Figure 2, the sleeve jacket, i.e. the cylindrical section 9 and the neck section 11, are made from one piece. For example, the neck section 11 can be produced by deep drawing and prepared for assembly in the base piece 5.

[0058] The base piece 5 has a central recess 7 for receiving the case jacket 3. Opposite the recess 7, the base piece 5 has another central, cylindrical recess 21, in which a primer cap (not shown) is received. In the following description, the recess 7 is referred to as the receptacle 7, and the recess 21 as the primer cap receptacle 21. The base piece 5 also has a central ignition bore 15', which is defined by an annular jacket 25 of the base piece and opens into both recesses 7, 21. In the embodiment shown in Figure 2, the jacket 25 forms a web 27. The primer cap receptacle 7 extends from a primer-side underside 19 of the base piece 5 in the direction of a projectile-side upper side 29 of the base piece 5 up to the web 17.From the projectile-side upper side 21, the receptacle 5 for the casing jacket 3 extends in the direction of the primer-side underside 19 of the base piece 5 up to the web 17. In a further embodiment of the base piece 5, the receptacle 5 can open directly into the primer receptacle 7 without a web being provided therebetween, as in Figure 1.

[0059] The base piece 5 also includes an extraction groove, which is generally designated by reference numeral 31 below. The extraction groove 31 is formed in an outer side of the base piece 5 and completely surrounds the base piece 5 in the circumferential direction. A firearm ejector can grasp and eject the empty cartridge case 1 via the extraction groove 31 after the projectile has been fired.

[0060] As can also be seen in particular from Figure 2, the fastening section 11 is essentially hourglass-shaped. This allows the positive and / or non-positive connection to the base piece 5 to be realized, since an overlap is formed with respect to the longitudinal direction, so that a separation of the base piece 5 and the sleeve shell 3 in the longitudinal direction or firing direction is prevented. To join the base piece 5 and the sleeve shell 3, the base piece is cold-formed in such a way that the wall surrounding the recess 7, which is formed by bending wings 33, is deformed radially inward, so that the sleeve shell 3 is elastically deformed at least in the region of the fastening section 11 and exerts an elastic deformation restoring force on the base piece 5 resulting from the cold forming.A key aspect of the present invention is that the material of the base piece 5 has a greater modulus of elasticity than the material of the sleeve shell 3. In this way, the springiness of the two joining partners after the pressing tool is removed is utilized to reinforce the clamping force exerted on each other by the base piece 5 and the sleeve shell 3. With the E-modules selected in this way, it is ensured that the springback of the sleeve shell 3 is greater than the corresponding springback of the base piece 5, so that additional prestress can be built up between the base piece 5 and the sleeve shell 3. The problem from the prior art that a certain amount of play can result between the base piece 5 and the sleeve shell 3 is thus prevented. For example, the base piece 5 comprises steel and the sleeve shell brass and / or aluminum. With this material selection, annealing processes in the area of ​​the joining contact can be avoided.

[0061] Referring to Figure 3, the corresponding figures (a), (b) and (c) schematically illustrate the manufacturing process of a cartridge case shell according to the invention and of a multi-part cartridge case 1 according to the invention. Figure 3a shows an intermediate stage of a cartridge case shell 3 according to the invention in the form of a deep-drawn, one-sidedly closed sleeve 35. The sleeve 35 can be produced by several deep-drawing steps starting from a punched blank and has a closed bottom 37 and an opposite open end 39 with a bent-up edge 41.

[0062] Figure 3b shows the case-like intermediate stage 35 in reverse orientation compared to Figure 3a. This is intended to highlight a key inventive concept of the present invention. According to prior art manufacturing methods, the open end 39 would be used to insert and receive the projectile. The closed base 37 would be severed to establish the connection with the base piece 5. According to the present invention, the manufacturing-related hardness profiles resulting from the final case jacket 3 were investigated, and characteristics were identified that are exploited according to the invention to create a cartridge case that is simpler and / or more cost-effective to manufacture and / or to more reliably ensure the functionality of the ammunition.In particular, it was found that by reversing the case-like intermediate stage 35, i.e. by assigning the open end 39, which was actually to be arranged on the projectile side, to the base piece 5 and by assigning the closed base 37, which was to be arranged on the base piece side according to the prior art, to the projectile holder, a cartridge case which is simpler and / or more cost-effective to produce can be created and its functionality can be improved.

[0063] Starting from the intermediate sleeve stage 35 shown in Figure 3b, further forming steps follow to achieve the final shape of the sleeve shell 3 according to the invention, as shown in Figure 3c in the assembled state with the base piece 5. Firstly, the strongly hardened and bent edge region 41 is separated and further formed by pressing into the final shape, which is designed for connection to the base piece 5. Secondly, the base 37 is perforated or punched out on the front side, i.e. in the area of ​​the closed base 37, and also formed by pressing into the final shape with the front indentation 43. For the joining of the base piece 5 and the sleeve shell 3, reference can be made to the relevant explanations in DE 10 2020 134 559 A1, the relevant content of which is incorporated herein by reference.

[0064] In Figure 4, chronologically successive figures 4a to 4d show schematic intermediate steps in the production of a sleeve shell 3 according to the invention using a tooling device, with the focus being on the punching or perforation of the closed base 37 of a further intermediate stage in the form of a formed sleeve 45. With regard to the sleeve intermediate stage 35 according to Figures 3a and 3b, according to the formed sleeve intermediate stage 45 from Figures 4a, 4b, the bent edge 41 has already been severed and the indentation 43 has already been introduced in the region of the closed base 47. To punch the closed base 37, the formed sleeve 45 is inserted into a punching station 50, which has a hollow cylindrical die 47 and a hollow cylindrical elongated punch 49, which is adapted to a dimension of the base section 51 to be separated or punched out.Due to the completed axial relative movement (Figure 4b), a circumferential cutting surface oriented in the longitudinal direction of the sleeve 45 is created, which is indicated by the reference number 53.

[0065] Referring to Figures 4c and 4d, a calibration station 60 is shown in which the sleeve 45 is calibrated and angled to a further intermediate stage. The intermediate product arranged in the calibration station 60 is indicated by the reference numeral 55. The calibration station comprises a pair of press punches 57, 59, which are inserted into the interior of the intermediate product 55 from opposite sides with respect to the longitudinal axis, as well as a pair of hollow cylindrical dies 61, 63 for external shaping and calibration.

[0066] The further exemplary embodiment of a cartridge case 10 according to the invention, shown in Figure 5, differs from the preceding embodiments of the cartridge case 1 in that the case jacket 3 does not rest on the upper side 29 of the base piece 5 in the region of the joining section, in particular in the region of the flexible wings 33 of the base piece 5. According to this embodiment, the case jacket 3 or its bottom 23 of the neck section 11 facing the base piece 5 does not have a radius due to manufacturing reasons. This leads, as can be seen in Figure 5, to an axial gap between the base piece 5, in particular the upper side 29 of the base piece 5, and the case jacket 3, in particular the bottom 23 of the neck section 11 of the case jacket 3. Because the case jacket 3 does not have a radius on the bottom side, it cannot be pressed into the base piece 5 without a gap.Furthermore, it has been found that when the sleeve shell 3 and the base piece 5 are joined together, the gap increases slightly, since the development of the bending line of the sleeve shell 3 increases during joining.

[0067] The features disclosed in the above description, the figures and the claims may be important both individually and in any combination for the realization of the invention in the various embodiments.

[0068] List of reference symbols

[0069] 1 cartridge case

[0070] 3 sleeve jacket

[0071] 5 base piece

[0072] 7 Deepening

[0073] 9 Cylinder section or sleeve section

[0074] 11 Neck section or fastening section

[0075] 13 Page

[0076] 15 Support shoulder

[0077] 15' ignition hole

[0078] 16 Transition

[0079] 19 undercut legs

[0080] 21 Frontal surface

[0081] 23 Floor

[0082] 25 coat

[0083] 27 jetty

[0084] 29 Top

[0085] 31 Extraction groove

[0086] 33 bending brackets

[0087] 35 sleeve-like intermediate stage

[0088] 37 closed floor

[0089] 39 broken end

[0090] 41 bent edge

[0091] 43 Constriction

[0092] 45 formed sleeve as an intermediate stage

[0093] 47 matrix

[0094] 49 stamps

[0095] 51 separated floor section

[0096] 52 punching station

[0097] 53 cutting surface

[0098] 55 Intermediate product

[0099] 57, 59 stamps

[0100] 61, 63 Die center axis

Claims

CLAIMS 1. Cartridge case for ammunition, in particular with a caliber of less than 20 mm, in particular less than 13 mm, comprising a rotationally symmetrical case jacket and a base piece fastened thereto by cold forming for receiving a primer cap, characterized in that the material of the base piece has a greater modulus of elasticity than the material of the case jacket.

2. Cartridge case according to claim 1, characterized in that the E-modulus of the base material is at least 50%, in particular at least 100%, 150% or at least 200%, greater than the E-modulus of the jacket material.

3. Cartridge case, in particular according to one of the preceding claims, for ammunition, in particular with a caliber of less than 20 mm, in particular of less than 13 mm, comprising a rotationally symmetrical case shell and a base piece for receiving a primer cap, wherein the base piece is fastened to the case shell by cold forming in such a way that the case shell is elastically deformed, characterized in that the case shell exerts an elastic deformation restoring force on the base piece resulting from the cold forming.

4. Cartridge case according to claim 3, characterized in that the base piece is elastically deformed during cold forming, wherein an elastic deformation restoring force of the base piece directed counter to the deformation is smaller than an elastic deformation restoring force of the case jacket directed counter to the deformation.

5. Cartridge case according to claim 4, characterized in that the deformation recovery path of the case jacket is at least 50%, in particular at least 100%, 150% or at least 200%, greater than the deformation recovery path of the base piece.

6. Cartridge case according to one of the preceding claims, characterized in that a fastening interface between The base piece and the sleeve jacket are at least partially, in particular completely, free from thermal post-treatment.

7. Cartridge case according to one of the preceding claims, characterized in that the base piece has a case jacket joining area for connecting to the case jacket and a receptacle for a primer cap facing away from the case jacket, wherein the case jacket joining area is subjected to a temperature treatment, in particular at a temperature exceeding the recrystallization temperature, wherein in particular the primer cap receptacle is free from a temperature treatment.

8. Cartridge case according to claim 7, characterized in that the case jacket joining area has a lower hardness than the primer cap receptacle, in particular by less than 10%, less than 20% or less than 30%.

9. A method for producing a cartridge case for ammunition, in particular with a caliber of less than 20 mm, in particular less than 13 mm, designed in particular according to one of the preceding claims, in which a base piece and a case jacket are fastened to one another by cold forming with elastic deformation of at least the case jacket and the elastically deformed case jacket exerts an elastic deformation restoring force on the base piece resulting from the cold forming.

10. The method according to claim 9, wherein the base piece, in particular before or during joining, is thermally post-treated in a sleeve shell joining area for connecting to the sleeve shell, in particular by means of induction or laser.

11. A method according to claim 9 or 10, which is designed to produce a cartridge case according to one of claims 1 to 8.

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