CN112338540A

CN112338540A - Composite boring and milling equipment for machining automobile piston

Info

Publication number: CN112338540A
Application number: CN202011467112.XA
Authority: CN
Inventors: 朱洪亮
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-12-14
Filing date: 2020-12-14
Publication date: 2021-02-09

Abstract

The invention discloses composite boring and milling equipment for machining an automobile piston, which comprises a base, a moving assembly, a workbench, a positioning and pressing assembly and a machining assembly, wherein the machining assembly comprises a first X-axis assembly, a second X-axis assembly and a Z-axis assembly, the first X-axis assembly is used for machining rough boring holes, clamping ring grooves and inner and outer chamfers of pin holes on two sides, the second X-axis assembly is used for machining fine boring holes and special-shaped pin holes, and the Z-axis assembly is matched with the moving assembly to complete machining of a valve pit and a combustion chamber in the top of a piston body. According to the invention, the piston is machined by multiple processes through one-time clamping, the machining of the X-axis assembly I, the X-axis assembly II and the Z-axis assembly are not interfered with each other, and the machining of the pin hole and the top surface of the piston body can be carried out simultaneously, so that the machining time is greatly saved, the boring and milling machining precision is improved, the labor intensity is reduced, and the production efficiency is improved.

Description

Composite boring and milling equipment for machining automobile piston

Technical Field

The invention relates to the field of machining, in particular to a composite boring and milling device for machining an automobile piston.

Background

The piston is an important component of an engine, the piston body is used as a main body of the piston, mechanical processing is completed by a plurality of processes, the processing of the piston body comprises rough and fine boring of a pin hole, turning of a clamping ring groove, internal and external chamfers, a special-shaped pin hole, a valve pit, a combustion chamber and the like, the rough and fine boring and the processing of the valve pit are realized by rough and fine processing in a boring time division manner, so that the requirement of tolerance precision is met, the processing of the valve pit and the combustion chamber is mainly completed by a milling machine at present, the rough and fine boring, the clamping ring groove and the internal and external chamfers are processed in a pin hole inner hole, the existing processing links comprise 6 processes, the 6 processes are completed by 3 to 6 devices, the processing precision of a product is influenced by frequent replacement, repositioning and tool clamping in the traditional processing mode, meanwhile, the benefit is low in labor.

With the release of the national standards V and VI of the engine, the requirement on the processing of the piston body of the engine is higher and higher, and the piston body has strong process characteristics in the aspect of cutting processing as a typical key part of an automobile. At present, the domestic piston manufacturing industry generally forms a machining production line by a general machine tool and special equipment combined with the technological characteristics of pistons, and most enterprises adopt a single-machine assembly line machining mode of the special machine tool, a modified common lathe, a special tool and a clamp to produce the piston, so that the special equipment becomes key equipment for cutting and machining the pistons, and the functions and the precision of the special equipment directly influence the quality indexes of the key characteristics of final products. Therefore, a novel piston boring and milling device is urgently needed to solve the problems.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the composite boring and milling equipment for processing the automobile piston, which solves the problems, and has the advantages that a plurality of processes are completed by one-time clamping, the pin holes, the clamping ring grooves, the inner and outer chamfers, the special-shaped pin holes are combined with the valve pits on the milled top surface and the combustion chamber, the processing time is saved, the labor intensity is reduced, and the production efficiency is improved.

In order to achieve the purpose, the invention provides the following technical scheme:

a composite boring and milling device for machining an automobile piston comprises a base, a moving assembly, a workbench, a positioning and pressing assembly and a machining assembly, wherein the moving assembly moving back and forth and moving left and right is stacked on the base, the workbench is arranged on the moving assembly, the positioning and pressing assembly for clamping the piston body is arranged on the workbench, the machining assembly comprises a first X axial assembly, a second X axial assembly and a Z axial assembly, the first X axial assembly and the second X axial assembly are arranged on the moving assembly on the left side and the right side of the workbench in a two-to-two mode, the first X axial assembly comprises a X1-axis linear sliding table, an X1 main shaft, an X1 main shaft motor, an X3982 driving motor, an X1 main shaft, a cutter head, a clamp ring groove cutter, a rough boring cutter and an inner and outer chamfering cutter, the X1 main shaft is mounted on a sliding block moving horizontally left and right of the X1-axis linear sliding table and is connected with an X1 main shaft motor in a, the clamping ring groove cutter, the rough boring cutter and the internal and external chamfering cutter are arranged at the front end of the unfolding cutter head through a cutter bar; the X axial component II comprises an X2 shaft linear sliding table, an X2 main shaft, an X2 main shaft motor, an elastic deformation boring head driving motor, an elastic deformation boring head and a fine boring cutter, wherein the X2 main shaft is installed on a left-right horizontally-moving sliding block of the X2 shaft linear sliding table and is in driving transmission connection with an X2 main shaft motor, the elastic deformation boring head is installed at the front end of the X2 main shaft and is in driving transmission connection with the elastic deformation boring head driving motor, and the fine boring cutter is installed at the front end of the elastic deformation boring head through a cutter bar; the Z-axis component is arranged above the piston body on the workbench and comprises a Z-axis linear sliding table, a Z-axis main shaft motor and a milling cutter, wherein the Z-axis main shaft is arranged on a slide block which vertically moves up and down of the Z-axis linear sliding table and is driven to be connected with the Z-axis main shaft motor, and the milling cutter is arranged at the bottom end of the Z-axis main shaft through a cutter bar.

According to a further improved technical scheme, the moving assembly comprises a Y-axis linear sliding table moving back and forth and an X-axis linear sliding table moving left and right, the X-axis linear sliding table is arranged on a sliding block table of the Y-axis linear sliding table, and the working table is arranged in the middle of the sliding block table of the X-axis linear sliding table.

According to a further improved technical scheme, the Y-axis linear sliding table comprises a Y-axis servo motor, a Y-axis driving screw rod, a Y sliding block table and a Y-axis sliding block guide rail, the X-axis linear sliding table comprises an X-axis servo motor, an X-axis driving screw rod, an X sliding block table and an X-axis sliding block guide rail, the Y sliding block table is arranged above the base, the Y-axis driving screw rod is rotatably arranged in the Y sliding block table, the Y-axis sliding block guide rails are symmetrically arranged between the base and the Y sliding block table on two sides of the Y-axis driving screw rod, and the output end of the Y-axis servo motor is in transmission connection with the; the X-axis slide block platform is arranged above the Y-axis slide block platform, the X-axis drive screw rod is rotatably arranged in the X-axis slide block platform, the X-axis slide block guide rails are symmetrically arranged between the Y-axis slide block platform and the X-axis slide block platform at two sides of the X-axis drive screw rod, and the output end of the X-axis servo motor is in transmission connection with the X-axis drive screw rod.

According to a further improved technical scheme, the Z-axis linear sliding table comprises a Z-axis servo motor, a Z-axis driving lead screw, a Z-axis sliding block table and a Z-axis sliding block guide rail, two rails of the Z-axis sliding block guide rail are vertically arranged on two sides of a piston body on a workbench, two ends of a top frame are connected to the top ends of the two rails, the Z-axis servo motor and a Z-axis spindle motor are arranged on the top frame, the Z-axis sliding block table is located between the two rails and is in sliding connection with the two rails, the Z-axis servo motor is in rotary connection with the Z-axis sliding block table through the Z-axis driving lead screw, and the output end of the Z.

According to a further improved technical scheme of the invention, the positioning and compressing assembly comprises a positioning spigot platform, oil cylinders, a support and a pressing block, wherein the positioning spigot platform is arranged on the workbench and used for clamping the spigot of the piston body, the oil cylinders are symmetrically arranged on the workbench at two sides of the piston body, the support is arranged above the oil cylinders and on the inner side of the cylinder rod, and the support and the upper ends of the cylinder rods of the oil cylinders are respectively hinged with the pressing block transversely arranged.

The invention further improves the technical scheme that an X1 spindle motor is in transmission connection with an X1 spindle, and an X2 spindle motor is in transmission connection with an X2 spindle through a conveyor belt.

According to a further improved technical scheme of the invention, the milling cutter is a valve pit milling cutter or a combustion chamber milling cutter.

According to a further improved technical scheme of the invention, an X1 main shaft is connected with a cutter expanding head through an X1 gearbox, and an X2 main shaft is connected with an elastic deformation boring head through an X2 gearbox.

The invention has the beneficial effects that:

the seam allowance of the piston body is connected to a seam allowance table of the positioning and pressing assembly in a meshing mode, the pressing block is pressed and fixed, the X-axis assembly moves towards the piston body to complete rough boring, clamping ring grooves and inner and outer chamfer processing of pin holes on two sides, and after the processing is completed, the X-axis assembly moves towards the piston body to complete fine boring and special-shaped pin hole processing; and meanwhile, the action of the X-axis assembly I and the action of the X-axis assembly II are not influenced by the action of the Z-axis assembly, the Z-axis assembly moves downwards, the machining of the valve pit at the top of the piston body and the machining of the combustion chamber are completed under the matching of the X-axis linear sliding table and the Y-axis linear sliding table, one device is clamped once to complete a plurality of machining processes, the machining time is shortened, the boring and milling machining precision is improved, the labor intensity is reduced, the machining cost is reduced, and the production efficiency is improved.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of a clamping piston body of the positioning and compressing assembly of the present invention.

Detailed Description

As shown in fig. 1 and 2, the present invention includes a base 1, a moving assembly 2, a workbench 3, a positioning and compressing assembly 4, and a processing assembly, wherein the moving assembly 2 is stacked on the base 1, and includes a Y-axis linear sliding table 21 moving back and forth and an X-axis linear sliding table 22 moving left and right, the Y-axis linear sliding table 21 includes a Y-axis servo motor 211, a Y-axis driving screw rod 212, a Y-axis sliding block table 213, and a Y-axis sliding block guide rail 214, the X-axis linear sliding table 22 includes an X-axis servo motor 221, an X-axis driving screw rod 222, an X-axis sliding block table 223, and an X-axis sliding block guide rail 224, the Y-axis sliding block table 213 is disposed above the base 1, the Y-axis driving screw rod 212 is rotatably disposed in the Y-axis sliding block table 213, the Y-axis sliding block guide rails 214 are symmetrically disposed between the base 1 and the Y-axis sliding; the X-axis slide block platform 223 is arranged above the Y-axis slide block platform 213, the X-axis drive screw rod 222 is rotatably arranged in the X-axis slide block platform 223, the X-axis slide block guide rails 224 are symmetrically arranged between the Y-axis slide block platform 213 and the X-axis slide block platform 223 on two sides of the X-axis drive screw rod, the output end of the X-axis servo motor 221 is in transmission connection with the X-axis drive screw rod 222, the middle position on the X-axis slide block platform 223 of the workbench 3 is provided with the positioning and pressing assembly 4 for clamping the piston body 5 on the workbench 3.

The positioning and compressing assembly 4 comprises a positioning spigot platform 41, an oil cylinder 42, a support 43 and a pressing block 44, wherein the positioning spigot platform 41 is arranged on the workbench 2 and used for clamping the spigot 51 of the piston body 5, the oil cylinders 42 are symmetrically arranged on the workbench 2 on two sides of the piston body, the support 43 is arranged above the oil cylinder 42 and on the inner side of the cylinder rod, and the upper ends of the cylinder rods of the support 43 and the oil cylinder 42 are respectively hinged with the pressing block 44 transversely arranged.

The machining assembly comprises a first X axial assembly 7, a second X axial assembly 8 and a Z axial assembly 6, the first X axial assembly 7, the second X axial assembly 8 are oppositely arranged on the left and right side moving assemblies 2 of the workbench 3, the first X axial assembly 7 is used for rough boring of pin holes on two sides, clamping ring grooves and inner and outer chamfering, the second X axial assembly 8 is used for machining special-shaped fine boring holes, the Z axial assembly 6 is arranged on the workbench 3 and located above the piston body 5, and the Z axial assembly 6 completes machining of a valve pit at the top of the piston body and machining of a combustion chamber (such as machining of special-shaped combustion chambers of a square combustion chamber, a pentagonal combustion chamber and the like) under the matching of the X-axis linear sliding table 22 and the Y-axis linear sliding.

The X axial assembly I7 comprises an X1 gearbox 70, an X1 shaft linear sliding table 71, an X1 main shaft 72, an X1 main shaft motor 73, an unfolding tool head driving motor 74, an unfolding tool head 75, a snap ring groove tool 76, a rough boring tool 77 and an inner and outer chamfering tool 78, wherein the X1 main shaft 72 is installed on a horizontal left-right moving slide block of the X1 shaft linear sliding table 71 and is in driven transmission connection with the X1 main shaft motor 73 through a transmission belt, the front end of the X1 main shaft 72 is connected with the X1 gearbox 70, the unfolding tool head 75 is installed on the X1 gearbox 70 and is in driven transmission connection with the unfolding tool head driving motor 74, and the snap ring groove tool 76, the rough boring tool 77 and the inner and outer chamfering tool 78 are installed at the front end of the unfolding.

The second X-axis assembly 8 comprises an X2 gearbox 80, an X2 axis linear sliding table 81, an X2 spindle 82, an X2 spindle motor 83, an elastic deformation boring head driving motor 84, an elastic deformation boring head 85 and a fine boring cutter 86, wherein the X2 spindle 82 is mounted on a horizontal left-right moving slide block of the X2 axis linear sliding table 81 and is driven to be in transmission connection with the X2 spindle motor 83 through a conveyor belt, the front end of the X2 spindle 82 is connected with the X2 gearbox 80, the elastic deformation boring head 85 is mounted on the X2 gearbox 80 and is driven to be connected with the elastic deformation boring head driving motor 84, and the fine boring cutter 86 is mounted at the front end of the elastic deformation boring head 85 through a cutter bar. The structure of the elastic deformation boring head 85 is an invention patent (grant publication No. CN 207343811U) granted by the inventor

The Z-axis assembly 6 comprises a Z-axis linear sliding table 61, a Z-axis spindle 62, a Z-axis spindle motor 63 and a milling cutter 64, wherein the Z-axis linear sliding table 61 comprises a Z-axis servo motor 611 and a Z-axis driving screw rod 612, the Z-axis slide block platform 613 and the Z-axis slide block guide rail 614 are arranged on two sides of the upper piston body 5 of the workbench in an upright mode, two ends of a top frame are connected to the top ends of the two rails, a Z-axis servo motor 611 and a Z-axis spindle motor 63 are arranged on the top frame, the Z-axis slide block platform 613 is located between the two rails and is in sliding connection with the two rails, the Z-axis servo motor 611 is rotatably connected with the Z-axis slide block platform 613 through a Z-axis driving screw rod 612, a Z-axis spindle 62 is arranged on the Z-axis slide block platform 613 which vertically moves up and down, the output end of the Z-axis spindle motor 63 is in rotating driving connection with the Z-axis spindle 62 through a transmission shaft 65, a milling cutter 64 is arranged at the bottom end of the.

When the piston body machining device is used specifically, a piston body 5 to be machined is placed on the workbench 3, the lower spigot 51 of the piston body 5 is meshed with the positioning spigot table 41 on the workbench 3, the piston body 5 is positioned, boring and milling equipment is started, the oil cylinders 42 on two sides of the piston body 5 work, the cylinder rods ascend, one end of the pressing block 44 is lifted, and the other end of the pressing block 44 is pressed on the top surface of the piston body 5 through the support 43. At the moment, the X1 spindle motor 73 and the servo motor of the X1 linear sliding table 71 are started simultaneously, the X1 spindle motor 73 drives the X1 spindle gearbox 70 to rotate through a conveyor belt, and the X1 spindle 72 and the cutter spreading head 75 synchronously rotate; the servo motor of the X1 shaft linear sliding table 71 rotates, the X1 shaft main shaft 72 axially moves to the workbench 3 through the slider guide rail of the X1 shaft linear sliding table, at the moment, the unfolding tool bit driving motor 74 is started to drive the unfolding tool bit 75 to provide radial feed for the rough boring tool 77, the inner and outer chamfering tool 78 and the snap ring groove tool 76, the rough boring hole 52, the inner and outer chamfering 57 and the snap ring groove 53 of the piston body 5 are machined, and after machining, the whole X1 shaft main shaft 72 axially moves to a starting position; then an X2-axis spindle motor 83 drives an X2-axis gearbox 80 to rotate through a conveyor belt, and an X2-axis spindle 82 and an elastic deformation boring head 85 synchronously rotate; the servo motor of the X2 axis linear sliding table 81 rotates, the X2 axis main shaft 82 axially moves to the workbench 3 through the slide block guide rail of the X2 axis linear sliding table, at the moment, the elastic deformation boring head driving motor 84 is started to drive the elastic deformation boring head 85 to provide the radial feed amount for the fine boring cutter 86, the fine boring hole 54 in the piston body 5 is precisely machined, the X2 axis main shaft 82 is systematically arranged, meanwhile, the machining of the special-shaped pin hole of the piston (such as a linear hole, a horn hole, an elliptical hole and the like) can be completed, and after the machining, the whole axial starting position of the X2 axis main shaft 82 moves. Because the actions of the first X-axis component 7, the second X-axis component 8 and the Z-axis component 6 are not interfered with each other, a valve pit or a combustion chamber on the top surface of a piston body can be processed simultaneously when a pin hole of the piston body is processed by the X-axis component, and therefore, the X-axis servo motor 221 is started at the same time, and the X-axis slide block 223 moves axially on the X-axis slide block guide rail 224 through the X-axis driving screw rod 222; starting a Y-axis servo motor 211, driving a screw rod 212 through a Y-axis, enabling a Y-axis slider table 213 to move radially on a Y-axis slider guide rail 214, and moving a piston body 5 to a coordinate position to be processed, at the moment, starting a Z-axis servo motor 611 of a Z-axis linear sliding table 61, and driving a Z-axis driving screw rod 612 to drive a Z-axis slider table 613 to move up and down along a track of a Z-axis slider guide rail 614; the Z-axis spindle motor 63 is started, the Z-axis spindle 62 is driven to rotate through the transmission shaft 65, the milling cutter 64 performs machining on the top wall piston valve pit 56 of the piston body 5 under the matching of the Y-axis linear sliding table 21 and the X-axis linear sliding table 22, (the milling cutter can also be replaced to perform machining on the piston top surface combustion chamber 55), and after the machining is completed, each axis moves to a starting position to wait for a machining instruction of a next product.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.

Claims

1. A compound boring and milling equipment for automobile piston processing which characterized in that: comprises a base (1), a moving component (2), a workbench (3), a positioning and pressing component (4) and a processing component, wherein the moving component (2) moving back and forth and moving left and right is overlapped on the base (1), the workbench (3) is arranged on the moving component (2), the positioning and pressing component (4) clamping a piston body (5) is arranged on the workbench (3), the processing component comprises a first X axial component (7), a second X axial component (8) and a Z axial component (6), the first X axial component (7) and the second X axial component (8) are oppositely arranged on the moving component (2) at the left side and the right side of the workbench (3), the first X axial component (7) comprises a linear sliding table (71) with an X1 axis, an X1 main shaft (72), an X1 main shaft motor (73), a cutter head driving motor (74), a cutter head (75), a clamp ring groove cutter (76), a rough boring cutter (77) and an inner chamfer cutter and an outer chamfer cutter (78), an X1 spindle (72) is arranged on a slider of a linear sliding table (71) of an X1 shaft, which moves horizontally left and right, and is driven to be connected with an X1 spindle motor (73), a spreading cutter head (75) is arranged at the front end of the X1 spindle (72), and is driven to be connected with a spreading cutter head driving motor (74), and a snap ring groove cutter (76), a rough boring cutter (77) and an inner and outer chamfering cutter (78) are arranged at the front end of the spreading cutter head (75) through cutter bars; the X axial component II (8) comprises an X2 shaft linear sliding table (81), an X2 main shaft (82), an X2 main shaft motor (83), an elastic deformation boring head driving motor (84), an elastic deformation boring head (85) and a fine boring cutter (86), the X2 main shaft (82) is installed on a left-right horizontally-moving sliding block of the X2 shaft linear sliding table (81), and is in driving transmission connection with the X2 main shaft motor (83), the elastic deformation boring head (85) is installed at the front end of the X2 main shaft (82), and is in driving transmission connection with the elastic deformation boring head driving motor (84), and the fine boring cutter (86) is installed at the front end of the elastic deformation boring head (85) through a cutter bar; z axial subassembly (6) are installed and are located piston body (5) top on the workstation, including Z axle straight line slip table (61), Z axle main shaft (62), Z axle spindle motor (63) and milling cutter (64), and Z axle main shaft (62) are installed on the slider of the upper and lower vertical movement of Z axle straight line slip table (61), and driven transmission connection Z axle spindle motor (63), and milling cutter (64) are installed in Z axle main shaft (62) bottom through the cutter arbor.

2. The composite boring and milling device for machining the automobile piston as claimed in claim 1, wherein: the movable assembly (2) comprises a Y-axis linear sliding table (21) moving back and forth and an X-axis linear sliding table (22) moving left and right, the X-axis linear sliding table (22) is arranged on a Y-axis sliding block table (213) of the Y-axis linear sliding table (21), and the workbench (3) is arranged in the middle of an X-axis sliding block table (223) of the X-axis linear sliding table (22).

3. The composite boring and milling device for machining the automobile piston as claimed in claim 2, wherein: the Y-axis linear sliding table (21) comprises a Y-axis servo motor (211), a Y-axis driving screw rod (212), a Y sliding block table (213) and a Y-axis sliding block guide rail (214), the X-axis linear sliding table (22) comprises an X-axis servo motor (221), an X-axis driving screw rod (222), an X sliding block table (223) and an X-axis sliding block guide rail (224), the Y sliding block table (213) is arranged above the base (1), the Y-axis driving screw rod (212) is rotatably arranged in the Y sliding block table (213), the Y-axis sliding block guide rail (214) is symmetrically arranged between the base (1) and the Y sliding block table (213) on two sides of the Y-axis driving screw rod, and the output end of the Y-axis servo motor (211) is in transmission connection with the Y-; x slider platform (223) are located Y slider platform (213) top, and X axle drive lead screw (222) rotate locate in X slider platform (223), and X axle slider guide rail (224) symmetry is located between Y slider platform (213) and the X slider platform (223) of X axle drive lead screw both sides, and X axle drive lead screw (222) are connected in the output transmission of X axle servo motor (221).

4. The composite boring and milling device for machining the automobile piston as claimed in claim 1, wherein: z axle straight line slip table (61) includes Z axle servo motor (611), Z axle drive lead screw (612), Z axle slider platform (613), Z axle slider guide rail (614), two tracks of Z axle slider guide rail (614) are found piston body (5) both sides on the workstation immediately, the roof-rack both ends are connected on two track tops, Z axle servo motor (611), Z axle spindle motor (63) are installed on the roof-rack, Z axle slider platform (613) are located between two tracks rather than sliding connection, Z axle servo motor (611) rotate through Z axle drive lead screw (612) and connect Z axle slider platform (613), Z axle spindle motor (63) output passes through transmission shaft (65) and is connected with Z axle main shaft (62) rotary drive.

5. The composite boring and milling device for machining the automobile piston as claimed in claim 1, wherein: the positioning and compressing assembly (4) comprises a positioning spigot platform (41), an oil cylinder (42), a support (43) and a pressing block (44), the positioning spigot platform (41) is arranged on the workbench (2) and used for clamping a piston body (5) spigot (51), the oil cylinder (42) is symmetrically arranged on the workbench (2) on two sides of the piston body, the support (43) is arranged above the oil cylinder (42) and is arranged on the inner side of the cylinder rod, and the upper ends of the cylinder rods of the support (43) and the oil cylinder (42) are respectively hinged with the pressing block (44) transversely arranged.

6. The composite boring and milling device for machining the automobile piston as claimed in claim 1, wherein: an X1 spindle motor (73) is in transmission connection with an X1 spindle (72), and an X2 spindle motor (83) is in transmission connection with an X2 spindle (82) through a conveyor belt.

7. The composite boring and milling device for machining the automobile piston as claimed in claim 1, wherein: the milling cutter (64) is a valve-pit milling cutter or a combustion chamber milling cutter.

8. The composite boring and milling device for machining the automobile piston as claimed in claim 1, wherein: the X1 main shaft (72) is connected with the cutter expanding head (75) through an X1 gearbox (70), and the X2 main shaft (82) is connected with the elastic deformation boring head (75) through an X2 gearbox (80).