Broaching arrangement for broaching workpiece that is coupled to lathe

Abstract

A broaching arrangement (1) is for broaching a workpiece (WP) that is coupled to a lathe (2). The broaching arrangement (1) comprises a body (3) attachable between a tailstock centre (4) and a headstock centre (5) of the lathe (2). The broaching arrangement further comprises a tool carriage (6) supported by the body (3) and movable back and forth relative to the body (3) in a Z-axis direction of the lathe (2). The broaching arrangement further comprises a carriage support (8) attached to the tool carriage (6) and attachable to a carriage (2.3) of the lathe (2) for moving the tool carriage (6) back and forth in the Z-axis direction of the lathe (2). The broaching arrangement further comprises a broaching tool holder (9) coupled to the tool carriage (6). The broaching arrangement further comprises a broaching tool (10) attachable to the broaching tool holder (9).

Description

[0001] BROACHING ARRANGEMENT FOR BROACHING WORKPIECE THAT IS COUPLED TO LATHE

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a broaching arrangement for broaching a workpiece that is coupled to a lathe .

[0004] BACKGROUND OF THE INVENTION

[0005] Key slots and other slots are conventionally machined to the workpieces , such as sleeves and splined shafts , in a separate milling or broaching machine . Typically, the workpiece is turned on a lathe to desired dimensions before broaching . The workpiece is removed from the lathe and thereafter mounted on the broaching machine , in which the slot is machined by a suitable broaching tool .

[0006] A drawback of the conventional broaching techniques is the manufacturing time and costs of the workpiece , for example .

[0007] The obj ect of the invention is to provide a broaching arrangement , by which the above-described drawbacks can be reduced .

[0008] SUMMARY

[0009] An obj ect of the present invention is to provide a novel broaching arrangement .

[0010] The invention is characteri zed by the features of the independent claims .

[0011] The invention is based on the idea of the broaching arrangement for broaching a workpiece that is coupled to a lathe . The broaching arrangement comprises a body attachable between a tailstock centre and a headstock centre of the lathe . The broaching arrangement further comprises a tool carriage supported by the body and movable back and forth relative to the body in a Z-axis direction of the lathe . The broaching arrangement further comprises a carriage support attached to the tool carriage and attachable to a carriage of the lathe for moving the tool carriage back and forth in the Z-axis direction of the lathe . The broaching arrangement further comprises a broaching tool holder coupled to the tool carriage . The broaching arrangement further comprises a broaching tool attachable to the broaching tool holder .

[0012] Significant advantages can be achieved by the means of the invention . By means of the broaching arrangement according to the invention the manufacturing process of the workpiece can be significantly speeded up because the slot can be machined to the workpiece in a lathe without removing the workpiece from the lathe . This also lowers the manufacturing costs of the workpiece .

[0013] Some embodiments of the invention are disclosed in the dependent claims .

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In the following the invention will be described in detail by means of examples with reference to the accompanying drawings , in which

[0016] Fig . 1 shows schematically a broaching arrangement and a lathe as seen obliquely from above of the broaching arrangement , Fig . 2 shows schematically a broaching arrangement of Fig . 1 without the lathe as seen obliquely from above of the broaching arrangement ,

[0017] Fig . 3 shows schematically a broaching arrangement of Fig . 2 as seen from above of the broaching arrangement ,

[0018] Fig . 4 shows schematically an exploded view of a broaching arrangement and a lathe of Fig . 1 as seen obliquely from above of the broaching arrangement ,

[0019] Fig . 5 shows schematically a detail of the broaching arrangement of Fig . 4 ,

[0020] Fig . 6 shows schematically a detail of the broaching arrangement of Fig . 2 , viewed from a side of the broaching arrangement as a partial longitudinal cross-sectional view,

[0021] Fig . 7 shows schematically a detail of a broaching arrangement of Fig . 2 , viewed from a side of the broaching arrangement as a partial longitudinal cross-sectional view,

[0022] Fig . 8 shows schematically a broaching arrangement and a lathe of Fig . 1 , viewed from above of the broaching arrangement as a partial longitudinal cross-sectional view, wherein the broaching arrangement is coupled to a workpiece ,

[0023] Fig . 9 shows schematically a broaching arrangement and a lathe of Fig . 1 , viewed from above of the broaching arrangement as a partial longitudinal cross-sectional view, wherein the broaching arrangement is coupled to a chuck of the lathe , and Fig . 10 shows schematically a broaching arrangement and a lathe as seen obliquely from above of the broaching arrangement .

[0024] For reasons of the clarity, some embodiments of the invention are illustrated in the figures in a simpli fied form . In the figures , like reference numerals identify like elements .

[0025] DETAILED DESCRIPTION

[0026] Fig . 1 shows schematically a broaching arrangement and a lathe as seen obliquely from above of the broaching arrangement . Fig . 2 shows schematically a broaching arrangement of Fig . 1 without the lathe as seen obliquely from above of the broaching arrangement . Fig . 3 shows schematically a broaching arrangement of Fig . 2 as seen from above of the broaching arrangement . Fig . 4 shows schematically an exploded view of a broaching arrangement and a lathe of Fig . 1 as seen obliquely from above of the broaching arrangement . Fig . 5 shows schematically a detail of the broaching arrangement of Fig . 4 . Fig . 6 shows schematically a detail of the broaching arrangement of Fig . 2 , viewed from a side of the broaching arrangement as a partial longitudinal cross-sectional view . Fig . 7 shows schematically a detail of a broaching arrangement of Fig . 2 , viewed from a side of the broaching arrangement as a partial longitudinal cross-sectional view . Fig . 8 shows schematically a broaching arrangement and a lathe of Fig . 1 , viewed from above of the broaching arrangement as a partial longitudinal cross-sectional view, wherein the broaching arrangement is coupled to a workpiece . Fig . 9 shows schematically a broaching arrangement and a lathe of Fig . 1 , viewed from above of the broaching arrangement as a partial longitudinal cross-sectional view, wherein the broaching arrangement is coupled to a chuck of the lathe . Fig . 10 shows schematically a broaching arrangement and a lathe as seen obliquely from above of the broaching arrangement.

[0027] The lathe 2 of the figures is a metal lathe. The metal lathe may be a center lathe, a turret lathe, a multispindle lathe, or a CNC lathe, for example.

[0028] The lathe 2 of the figures comprises a headstock 2.1 for providing a rotational power for operations of a workpiece WP . The headstock 2.1 comprises a chuck 17 for receiving the workpiece WP . The chuck 17 comprises jaws via which the workpiece WP can be attached to the chuck 17, for example. The lathe 2, or the headstock 2.1, has a head- stock centre 5. The chuck 17 is concentrically aligned relative to the headstock centre 5. Further, the workpiece WP is concentrically aligned relative to the headstock centre 5. The headstock 2.1 may further comprise a motor, a transmission, a control panel and other components for operating the chuck 17. The lathe 2 may further comprise a sensor arrangement for measuring a rotation angle of the chuck 17. The rotation angle of the chuck 17 can be utilized when broaching two or more slots in the work piece, for example. In other words, the angle between two slots can be determined by utilizing the information from the sensor arrangement.

[0029] The lathe 2 of the figures further comprises a tailstock 2.2 locating at a distance relative to the headstock 2.1. The lathe 2, or the tailstock 2.2, has a tailstock centre 4. The chuck 17 is concentrically aligned relative to the tailstock centre 4. Thus, the chuck 17 is concentrically aligned relative to the tailstock centre 4 and the head- stock centre 5. The tailstock 2.2 is used for supporting the body 3 of the broaching arrangement 1, which is disclosed in more detail below. The lathe 2 of the figures further comprises a carriage 2.3. The carriage 2 is responsible for guiding the tool bit as it cuts or otherwise operates the workpiece. The carriage 2.3 locates between the headstock 2.1 and the tailstock 2.2. The carriage can be moved in the Z-axis direction of the lathe. Further, the carriage can be moved in the X-axis direction of the lathe. In more detail, a cross-slide 2.31 of the carriage 2.3 is moved in the X- axis direction of the lathe. There are tracks via which the carriage 2.3 travels. During lathing the workpiece WP, the carriage is used for moving a lathing tool for lathing the workpiece. The workpiece WP is typically rotated by the lathe during lathing the workpiece WP . During broaching the workpiece, the carriage is used for moving the broaching tool for broaching the workpiece. The workpiece WP may be held in place during broaching the work piece WP . For sake of the clarity, the lathing tool for lathing the workpiece may be removed and / or moved aside before broaching the workpiece.

[0030] The lathe 2 of the figures further comprises a tool turret 26. In more detail, the carriage 2.3 comprises the tool turret 26. The tool turret 26 may be a disc-type turret as shown in the figure 10, head-type turret as shown in the figure 1, or a crown-type turret (not shown in the figures) , for example. The tool turret 26 may be configured to hold multiple tool holders and tools. The tool turret 26 can be driven in the Z-axis direction of the lathe. The tool turret 26 can be moved in the X-axis direction of the lathe. Movements in the Z-axis direction and the X-axis direction are executed by the carriage 2.3.

[0031] The lathe 2 of the figures comprises a bed 2.4, i.e., a platform, to which the headstock 2.1, the tailstock 2.2, and the carriage 2.3 are mounted / coupled . The bed supports said components of the lathe 2 during operations of the lathe . The Z-axis direction Z shown in the figures refers to the axis along which the cutting tool moves parallel to the rotational axis of the chuck 17 . In other words , the Z- axis direction is a longitudinal axis direction of the lathe 2 . In other words , the Z-axis direction is a longitudinal axi s direction of the broaching arrangement 1 . Movement along the Z-axis involves moving the tool closer to or farther from the headstock along the length of the workpiece WP .

[0032] The X-axis direction X shown in the figures is perpendicular to Z-axis direction . In other words , the X-axis direction X is a radial direction of the broaching arrangement 1 / the lathe 2 . In other words , the X-axis direction X is a hori zontal direction and / or a vertical direction of the broaching arrangement 1 / the lathe 2 . The x-axis direction X can be divided into components as follows and as shown the figure 1 . A first X-axis direction XI is a hori zontal direction of the lathe , which hori zontal direction is perpendicular to Z-axis direction . A second X- axis direction X2 that is a vertical direction of the lathe , which hori zontal direction is perpendicular to Z- axis direction .

[0033] The broaching arrangement 1 of the f igures is configured to be installed in the lathe 2 . The workpiece WP to be broached is attached to the chuck 17 of the lathe , be- tween / around the j aws of the chuck 17 . Said attachment centers the workpiece WP relative to the chuck 17 .

[0034] The broaching arrangement 1 of the figures comprises a body 3 , which is attached / coupled between the between a tailstock centre 4 and a headstock centre 5 of the lathe 2 . Said attachment / coupling centers the body 3 relative to the chuck 17 , thus relative to the work piece WP . A purpose of the body 3 is to support the broaching arrangement 1 during the workpiece WP being broached. The body 3 comprises a first end 3.1 and a second end 3.2 locating opposite to the first end 3.1. The first end 3.1 of the body 3 is placed against / towards headstock centre 5.

[0035] Further, the body 3, or the first end 3.1 of the body 3, can be supported to the chuck 17 of the lathe 2 as seen in the figure 9, for example. The body 3, or the first end 3.1 of the body 3, can be supported to the workpiece WP as seen in the figure 8, for example. The second end 3.2 of the body 3 is placed against / towards the tailstock centre 4.

[0036] The body 3 of the broaching arrangement 1 of the figures comprises a first centre recess 3.12 locating at the first end 3.1 of the body 3. Said first centre recess 3.12 is used for centering the body relative to the headstock centre 5. Further, the body 3 comprises a second centre recess 3.22 locating at the second end 3.2 of the body 3. Said second centre recess 3.22 is used for centering the body relative to the tailstock centre 4. For sake of the clarity, in addition or alternatively, the body 3 can be centered relative to the headstock centre by using a chuck brake 16 that is disclosed in more detail below.

[0037] The body 3 of the broaching arrangement of the figures comprises a first support piece 3.11 locating at the first end 3.1 of the body 3. The first support piece 3.11 is placed against / towards headstock centre 5. The first support piece 3.11 may be cylindrical, for example. Said first support piece 3.11 is a separate piece as illustrated in the figures 1-9, or integrated to the body 3 as illustrated in the figure 10. The first support piece 3.11 may be called the first support section. The body 3 of the figures comprises a second support piece 3.21 locating at the second end 3.2 of the body 3. The second support piece 3.21 is placed against / towards tail- stock centre 4. The second support piece 3.21 may be cylindrical, for example. Said second support piece 3.12 is a separate piece as illustrated in the figures 1-9, or integrated to the body 3 as illustrated in the figure 10. The second support piece may be called the second support section .

[0038] The body 3 of the broaching arrangement of the figures further comprises at least one guide 3.3 for guiding a tool-carriage 6, which tool-carriage 6 is disclosed in more detail below. The at least one guide 3.3 locates between the first support piece 3.11 and the second support piece 3.21. The at least one guide 3.3 is attached to the first support piece 3.11 and the second support piece 3.21. The body 3 of the figures 1-9 comprises two cylindrical guides 3.3. The body 3 of the figure 10 has one cylindrical guide 3.3 integrated to the body 3 with the first and second support pieces.

[0039] The broaching arrangement 1 of the figures further comprises a tool-carriage 6. The tool-carriage 6 is supported by the body 3. In more detail, the tool-carriage 6 is coupled to the at least on guide 3.3 of the body 3. The tool-carriage 6 has an inner opening 6.3 through which the body 3 extends. In more detail, the at least one guide 3.3 extends through said inner opening of the tool-carriage 6. The tool-carriage 6 is movable back and forth relative to the body 3 in the Z-axis direction Z of the lathe 2. The tool-carriage 6 may be mounted via bearings to the body 3. The tool-carriage 6 may comprise a front bearing and rear bearing arranged against the outer surface of the body 3. The tool-carriage 6 of the figures comprises a housing 6.1. The housing 6.1 forms an inner space 6.4 for accommodating the carriage support 8, the broaching tool holder 9, and / or the transfer mechanism 11, which components are disclosed in more detail below. The tool-carriage 6 of the figures 1-9 comprises a cover 6.2 attached to the housing 6.1 for covering the inner space 6.4 of the housing 6.1.

[0040] The housing 6.1 of the figures has the above-mentioned inner opening 6.3 through which the body 3 extends. The inner opening 6.3 of the body 3 extends in the Z-axis direction of the lathe 2. There may be at least one bearing arranged inside the inner opening 6.3 of the housing 6.1. In other words, there may be at least one bearing arranged between the inner opening 6.3 of the housing 6.1 and the guide 3.3 of the body 3.

[0041] The broaching arrangement 1 of the figures comprises a carriage support 8. The carriage support 8 is movably attached to the tool-carriage 6. The carriage support 8 is attachable / attached to the carriage 2.3 of the lathe 2. In more detail, the carriage support 8 is attachable / attached to the tool turret 26 of the carriage 2.3. The carriage support 8 is movable in X-axis direction of the lathe 2 with respect to the tool-carriage 6. The carriage support 8 of the figures 1-9 is a metal plate, which metal plate is arranged into the inner space 6.4 of the housing 6.1, and which metal plate extends out from the inner space 6.4. The carriage support 8 of the figure 10 is a fork-shaped structure movably attached to the tool-carriage 6.

[0042] The tool-carriage 6 of the figures comprises a first guide 6.11 for guiding the carriage support 8 to move in the X- axis direction of the lathe with respect to the toolcarriage 6. Said first guide 6.11 is shown in the figure 5, for example. The first guide 6.11 of the figures 1-9 is a groove that is arranged into the housing 6.1. The first guide 6.11 of the figure 10 is a housing structure that partially surrounds the carriage support 8, and which housing structure is attached to the housing 6.1 of the tool-carriage 6.

[0043] The broaching arrangement 1 of the figures further comprises a broaching tool holder 9. The broaching tool holder 9 is coupled to / in connection with the tool-carriage 6. The broaching tool holder 9 of the figures is movably attached to the tool-carriage 6. The tool holder 9 extends outside the tool-carriage 6. The tool holder 9 may be a metal plate, for example.

[0044] The tool-carriage 6 of the figures comprises a second guide 6.12 for guiding the broaching tool holder 9 to move in X-axis direction of the lathe with respect to the toolcarriage 6. The second guide 6.12 of the figures 1-9 is a groove that is arranged into the housing 6.1. The second guide 6.12 of the figure 10 is a recess that is arranged through the body 3. For sake of the clarity, the second guide 6.12 and the first guide 6.11 may be arranged towards different X-axis directions. The first guide 6.11 may be arranged towards the first X-axis direction XI, and the second guide 6.12 may be arranged towards the second X-axis direction X2, for example.

[0045] The broaching arrangement 1 of the figures comprises a broaching tool 10 attached to the broaching tool holder 9. In more detail, the broaching tool 10 is attached to the portion of the tool holder 9 that locates outside the housing 6.1 of the tool-carriage 6. The broaching tool 10 can be installed to the broaching tool holder 9 and further, the broaching tool 10 can be removed from the broaching tool holder 9. Fasteners such as bolts can be used for coupling the broaching tool 10 and the broaching tool holder 9 together, for example. During broaching of the workpiece WP, the broaching tool 10 broaches a desired shape to the workpiece WP. The desired shape may be a slot, a spline, a polygon, or such, for example.

[0046] The broaching arrangement 1 of the figures comprises a transfer mechanism 11 for adjusting a broaching depth of the broaching tool 10. In more detail, the tool-carriage 6 comprises said transfer mechanism 11. The transfer mechanism 11 is configured to transfer the movement of the carriage support 8 in the X-axis direction of the lathe 2 to the movement of the broaching tool holder 9 in the X-axis direction of the lathe 2. Thus, the broaching depth of the broaching tool 10 can be adjusted. The transfer mechanism 11 may be called a first transfer mechanism 11.

[0047] The transfer mechanism 11 of the figures comprises a transfer arm 13. The transfer arm 13 is configured to move relative to the tool-carriage 6 and / or the body 3 in the Z-axis direction of the lathe 2. The transfer arm 13 is mechanically linked to the carriage support 8. Further, the transfer arm 13 is mechanically linked to the broaching tool holder 9. The transfer arm 13 of the figures 1- 9 is arranged to the inner space 6.4 of the housing 6.1. The transfer arm 13 of the figure 10 is arranged inside the recess of the body 3.

[0048] The tool-carriage 6 of the figures comprises a third guide 6.13 for guiding the transfer arm 13 to move in Z-axis direction of the lathe with respect to the tool-carriage 6 and / or the body 3. The third guide 6.13 of the figures 1-9 is arranged into the housing 6.1 in Z-axis direction of the lathe. The third guide 6.13 of the figure 10 is arranged into the recess of the body 3 in Z-axis direction of the lathe 2. The transfer mechanism 11 of the figures further comprises a first conversion mechanism 14 for coupling the transfer arm 13 and the carriage support 8. The first conversion mechanism 14 is configured to convert the movement of the carriage support 8 in the X-axis direction of the lathe 2 to the movement of the transfer arm 13 in the Z-axis direction of the lathe 2. The transfer mechanism 11 further comprises a second conversion mechanism 15 for coupling the transfer arm 13 and the broaching tool holder 9. The second conversion mechanism 15 is configured to convert the movement of the transfer arm 13 in the Z-axis direction of the lathe 2 to the movement of the broaching tool holder 9 in the X-axis direction of the lathe 2.

[0049] The first conversion mechanism 14 of the figures comprises a groove 14.1 and a projecting part 14.2 extending to the groove 14.1. The groove 14.1 may be called a first groove 14.1, and the projecting part 14.2 may be called a first projecting part 14.2. The first conversion mechanism 14 couples the carriage support 8 and the transfer arm 13. The groove 14.1 is arranged in the carriage support 8. Alternatively, the groove 14.1 is arranged in the transfer arm 13. The groove 14.1 is at an angle with respect to the X-axis of the lathe 2. When the groove is arranged to the carriage support, said projecting part 14.2 is arranged to the transfer arm 13. Alternatively, when the groove is arranged to the transfer arm, the projecting part 14.2 is arranged to the carriage support 8. Thus, the movement of the carriage support 8 in the X-axis direction of the lathe 2 is converted into the movement of the transfer arm 13 in the Z-axis direction of the lathe 2.

[0050] The second conversion mechanism 15 of the figures comprises a second groove 15.1 and a second projecting part 15.2 extending to the second groove 15.1. The second conversion mechanism 15 couples the broaching tool holder 9 and the transfer arm 13. The second groove 15.1 is arranged in the broaching tool holder 9. Alternatively, the second groove 15.1 is arranged in the transfer arm 13. The second groove 15.1 is at an angle with respect to the X-axis of the lathe 2. When the groove is arranged to the broaching tool holder, the second projecting part 15.2 is arranged in the transfer arm 13. Alternatively, when the groove is arranged to the transfer arm, the second projecting part 15.2 is arranged in the broaching tool holder 9. Thus, the movement of the transfer arm 13 in the Z- axis direction of the lathe 2 is converted to the movement of the broaching tool holder 9 in the X-axis direction of the lathe 2.

[0051] The broaching arrangement 1 of the figure 10 comprises a second transfer mechanism for adjusting an angle of the broaching tool holder 9 relative to the carriage support 8. The second transfer mechanism allows a rotational movement around the Z-axis direction of the broaching arrangement. Thus, said angle is adjusted around the Z-axis direction of the lathe 2. The second transfer mechanism comprises a joint for allowing the rotational movement around the Z-axis direction. The joint locates between the first conversion mechanism 14 of the transfer mechanism 11 and the second conversion mechanism 15 of the transfer mechanism 11, for example. Further, the toolcarriage 6 is arranged rotatably around the body 3. The tool-carriage 6 of the figure 10 has a cylindrical inner surface around the body 3, thereby allowing the rotational adjustment between the body 3 and the tool-carriage 6.

[0052] The broaching arrangement 1 of the figure 10 comprises a Z-axis support 20 for supporting the broaching arrangement 1. The Z-axis support 20 is attached to the lathe 2 and to the broaching arrangement 1. In more detail, the Z-axis support 20 is attached to the carriage 2.3, whereby the Z-axis support 20 moves in the Z-axis direction of the lathe 2. In more detail, the Z-axis support 20 is attached to the tool-holder 6. For sake of the clarity, the Z-axis support 20 is only shown in the figure 10, but the Z-axis support 20 may be used also in the broaching arrangement shown in the figures 1-9.

[0053] The broaching arrangement 1 of the figures comprises a chuck brake 16 for preventing the rotational movement of the chuck 17 of the lathe 2. In more detail, the body 3 of the broaching arrangement comprises the chuck brake. The chuck brake 16 comprises friction pads 18, typically 3-6 friction pads 18, having a first position, in which the rotation of the chuck 17 is allowed, and a second position, in which the friction pads 18 are pressed against the central hole surface of the chuck 17. Thus, the friction pads 18 prevent the rotational movement of the chuck 17 relative to the broaching arrangement 1. The chuck brake 16 of the figures is operated hydraulically.

[0054] The chuck brake 16 of the figures comprises a hydraulic channel 22. The hydraulic channel 22 is arranged into the body 3. In more detail, the hydraulic channel 22 is arranged to the first support piece 3.11 and the second support piece 3.12 of the body 3. The first support piece 3.11 and the second support piece 3.12 are connected to each other by a hydraulic path 22.1. The hydraulic path 22.1 may be a hydraulic pipe, a path extending in the body, or a hydraulic hose for example. The hydraulic channel 22 is f illable / f illed with hydraulic liquid. The hydraulic channel 22 extends in the Z-axis direction of the lathe 2. The body 3 comprises radial holes 23 extending from the hydraulic channel 22 to the outer surface of the body 3. The radial holes 23 are arranged in fluid communication with the friction pads 18. In other words, the friction pads 18 are arranged in the radial holes 23. The chuck brake 16 of the figures comprises a control member 22.2 for controlling the position of the friction pads 18. The control member 22.2 is arranged to the second end 3.2 of the body 3. In more detail, the control member 22.2 is arranged to the second support piece 3.21 of the body 3. The control member 22.2 is in connection with the hydraulic channel 22. The control member 22.2 is configured to be pressed by the tailstock centre 4. The control member 22.2 provides the pressure to be increased in the hydraulic channel 22, whereby the friction pads 18 are forced to move from the first position to the second position. The chuck brake 16 of the figures comprises a sealing 22.3 arranged around the control member 22.2 for preventing a leakage of the hydraulic oil. According to an embodiment, the control member can be located elsewhere in on the body 3, and the control member is pressed manually.

[0055] The chuck brake 16 further comprises a springs 24 configured to force the friction pads 18 to move from the second position to the first position. Each spring 24 is coupled to the corresponding friction pad 18. The chuck brake 16 is intended to be used in connection with the lathes 2 that do not comprise a spindle brake.

[0056] The broaching arrangement 1 may be operated as follows. The workpiece WP to be machined is mounted between / around the jaws of the chuck 17. The workpiece is sleeve-like, and the slot is machined into the inner surface of the workpiece. The workpiece may be turned before or after the broaching if necessary.

[0057] When the broaching operation is started, the body 3 of the broaching arrangement 1 is attached between the tail- stock centre 4 and headstock centre 5 of the lathe 2. The first end of the body 2 is placed against headstock centre 5 and the tailstock centre 4 is moved against the second end of the body 3 . The tailstock centre 4 presses the control member 22 . 2 , and the pressure of the hydraulic liquid in the hydraulic channel 22 urges the friction pads 18 against the surface of the central hole of the chuck 17 .

[0058] The carriage support 8 is attached to the tool turret 26 or the carriage of the lathe 2 . A suitable broaching tool

[0059] 10 is attached to the tool holder 9 . The broaching depth is set as desired by moving the carriage support 8 in the X-axis direction of the lathe 2 . The transfer mechanism

[0060] 11 transfers the movement of the carriage support 8 to the movement of the tool holder 9 and the broaching tool 10 in the X-axis direction of the lathe 2 .

[0061] The carriage support 8 and thus the tool-carriage 6 , the broaching tool holder 9 and the broaching tool 10 are moved back and forth in the Z-axis direction of the lathe 2 by the carriage of the lathe 2 . The carriage support 8 may be moved in the X-axis direction of the lathe to adj ust broaching depth of the broaching tool 10 . The broaching tool 10 broaches a key s lot or other slot into the workpiece . The length of the slot is set as desired by adj usting the length of the stroke of the carriage holder 8 in the Z-axis direction of the lathe 2 .

[0062] A method for lathing and broaching a workpiece WP comprises coupling a workpiece WP to a lathe 2 . The method further comprises lathing the workpiece WP by the lathe 2 . The method further comprises coupling the broaching arrangement 1 to the lathe 2 . The body 3 of the broaching arrangement 1 is locating between a tailstock centre 4 and a headstock centre 5 of the lathe 2 . The method further comprises broaching the workpiece WP by the broaching arrangement 1 . The body 3 of broaching arrangement 1 is placed through the workpiece WP or into the workpiece WP . The method further comprises adj usting a broaching depth of the broaching tool 10 of the broaching arrangement 1 . The inner surface of the workpiece WP i s broached by the broaching arrangement 1 .

[0063] A spiral slot may be machined to the workpiece by turning the chuck 17 simultaneously as the broaching tool 10 is moved in the Z-axis direction . It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways . The invention and its embodiments are thus not limited to the examples described above , instead they may vary within the scope of the claims .

Claims

CLAIMS1. A broaching arrangement (1) for broaching a workpiece (WP) that is coupled to a lathe (2) , wherein the broaching arrangement (1) comprises:- a body (3) attachable between a tailstock centre (4) and a headstock centre (5) of the lathe (2) ,- a tool carriage (6) supported by the body (3) and movable back and forth relative to the body (3) in a Z-axis direction of the lathe (2) ,- a carriage support (8) attached to the tool carriage (6) and attachable to a carriage (2.3) of the lathe (2) for moving the tool carriage (6) back and forth in the Z-axis direction of the lathe (2 ) ,- a broaching tool holder (9) coupled to the tool carriage ( 6) ,- a broaching tool (10) attached to the broaching tool holder (9) and- a transfer mechanism (11) for adjusting a broaching depth of the broaching tool (10) , which transfer mechanism (11) is configured to transfer the movement of the carriage support (8) in the X-axis direction of the lathe (2) to the movement of the broaching tool holder (9) in the X-axis direction of the lathe (2 ) .

2. The broaching arrangement (1) according to claim 1, characterized in that the transfer mechanism (11) comprises-a transfer arm (13) coupled to the tool-carriage (6) and configured to move relative to the toolcarriage (6) in the Z-axis direction of the lathe (2) ,-a first conversion mechanism (14) for coupling the carriage support (8) and the transfer arm (13) , which first conversion mechanism (14) is configured to convertthe movement of the carriage support (8) in the X-axis direction of the lathe (2) to the movement of the transfer arm (13) in the Z-axis direction of the lathe (2) , and-a second conversion mechanism (15) for coupling the broaching tool holder (9) and the transfer arm (13) , which second conversion mechanism (15) is configured to convert the movement of the transfer arm (13) in the Z- axis direction of the lathe (2) to the movement of the broaching tool holder (9) in the X-axis direction of the lathe (2 ) .

3. The broaching arrangement (1) according to claim 2, characterized in that the first conversion mechanism (14) comprises a groove (14.1) and a projecting part (14.2) extending to the groove (14.1) , wherein the movement of the carriage support (8) in the X-axis direction of the lathe (2) is converted to the movement of the transfer arm (13) in the Z-axis direction of the lathe (2) .

4. The broaching arrangement (1) according to claim 3, characterized in that the second conversion mechanism (15) comprises a second groove (15.1) and a second projecting part (15.2) extending to the second groove (15.1) transfer arm , wherein the movement of the transfer arm (13) in the Z-axis direction of the lathe (2) is converted to the movement of the broaching tool holder (9) in the X- axis direction of the lathe (2) .

5. The broaching arrangement (1) according to any of the preceding claims, characterized in that the body (3) comprises a chuck brake (16) for preventing the rotational movement of the chuck (17) of the lathe (2) relative to the broaching arrangement (1) .

6. The broaching arrangement (1) according to claim 5, characterized in that the chuck brake (16) comprises friction pads (18) having a first position, in which therotation of the chuck (17) is allowed, and a second position, in which the friction pads (18) are configured to be pressed against a central hole surface of the chuck (17) , thus preventing the rotational movement of the chuck (17) relative to the broaching arrangement (1) .

7. The broaching arrangement (1) according to claim 6, characterized in that the chuck brake (16) comprises a hydraulic channel (22) in the body (3) , and radial holes (23) extending from the hydraulic channel (22) to the outer surface of the body (3) , wherein the friction pads (18) are arranged to the radial holes (23) .

8. The broaching arrangement according to any of the preceding claims, characterized in that the carriage support (8) is attached to a tool turret (26) of the carriage (2.3) of the lathe (2) .

9. A lathe (2) , characterized in that the lathe (2) comprises a broaching arrangement (1) according to any of the preceding claims, wherein the body (3) of the broaching arrangement (1) is attached between a tailstock centre (4) and a headstock centre (5) of the lathe (2) , and the carriage support (8) is attached to the carriage (2.3) of the lathe (2 ) .

10. A method for lathing and broaching a workpiece (WP) , the method comprising-coupling a workpiece (WP) to a lathe (2) , -lathing the workpiece (WP) by the lathe (2) , -coupling a broaching arrangement (1) to the lathe (2) , the body (3) of the broaching arrangement (1) locating between a tailstock centre (4) and a headstock centre (5) of the lathe (2) ,-broaching the workpiece (WP) by the broaching arrangement( 1 ) , and-adjusting a broaching depth of the broaching tool (10) by a transfer mechanism (11) which transfer mechanism (11) is configured to transfer the movement of the carriage support (8) in the X-axis direction of the lathe (2) to the movement of the broaching tool holder (9) in the X-axis direction of the lathe (2 ) .

11. The method as claimed in claim 10, wherein the body (3) of broaching arrangement (1) is placed through the workpiece (WP) or into the workpiece (WP) .

12. The method as claimed in claim 10 or 11, the method further comprising-adjusting a broaching depth of the broaching tool (10) of the broaching arrangement (1) .

13. The method as claimed in any one of claims 10-12, wherein the inner surface of the workpiece (WP) is broached by the broaching arrangement (1) .

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