Spindle fastening device

Abstract

Spindle fastening device comprising: a device body (51) having a mounting surface detachably attached to an end surface of the spindle head (22); Engagement means (45, 62, 42, 42a, 42b, 43, 44) for moving the device body (51) in an axial direction of the spindle (21) to engage the spindle head (22) and the device body (51) with each other and thus freely limit or release the rotation of the device body (51) with respect to the spindle head (22) about the longitudinal axis of the spindle; Spring means (59) for urging the fixture body (51) so that the mounting surface of the fixture body (51) is pressed against the end surface of the spindle head (22) with the engagement means (45, 62) ready for connection; Fluid pressure means (42, 42a, 42b) for generating a fluid pressure acting on the mounting surface of the device body (51) against the spring force of the spring means (59), so that the connection of the engagement means (45, 62) is released; and Transmission means (35, 61) for transmitting the rotation of the spindle (21) to the device body (51) by the fluid pressure of the fluid pressure means (42, 42a, 42b) acting on the mounting surface of the device body (51).

Description

The present invention relates to a spindle mounting device using a cutting device for use as a machine tool on a spindle head.A previously known example of a device of this type is a device comprising a device body having a mounting surface detachably mounted on an end surface of the spindle head, and engaging means for engaging the spindle head and the device body by moving the device body in an axial direction of the spindle, thereby freely limiting or releasing the rotation of the device body with respect to the spindle head about the longitudinal axis of the spindle, wherein a tension bolt is held by the device body so as to be freely movable in an axial direction. When the longitudinal axis of the tension bolt coincides with the longitudinal axis of the spindle, the tension bolt is inserted into an axial opening of the spindle and connected to the coupling rod. In this state, the device body descends due to its own weight, in which state the device body hangs on the spindle head by the tension bolt. The apparatus has transmission means for transmitting the rotation of the spindle to the apparatus body in this state (for example, see Japanese Unexamined Patent Publication No. S 59-219129).In this conventional apparatus, when the engagement of the engaging means is released and the apparatus body rotates, the apparatus body hangs on the spindle head, so that the rotation is in a very unstable position.Therefore, it is very difficult to lift the device body and engage the engaging means during the rotation of the device body.Further, after the engaging means are engaged, the position of the device body is unstable during rotation, which may necessitate connection between the spindle head and the device body. In this case, because the position of the device body is unstable during rotation, it is necessary to provide a large engaging gap. However, when a large engaging gap is provided, there is a possibility that a foreign material may permeate into the spindle head through the gap.A spindle fastening device is disclosed in JP S59-219 129 A A. It comprises a jig body having a mounting surface detachably mounted on an end surface of the spindle head, and engaging means for engaging the spindle head and the jig body by moving the jig body in an axial direction of the spindle, thereby preventing or releasing the rotation of the jig body with respect to the spindle head about the longitudinal axis of the spindle. A further device for spindle fastening is known from U.S. Pat. No. 6,865,789 B2.It is an object of the invention to provide a spindle fixing device capable of rotating the device body in a stable position when a fixing surface of the device body is fixed to or detached from an end surface of the spindle head.This object is achieved by a spindle fastening device having the features of claim 1. Practical refinements and advantageous embodiments of the invention are specified in the dependent claims.A spindle fixing device of the present invention comprises a device body having a fixing surface detachably fixed to an end surface of the spindle head, engaging means for moving the device body in an axial direction of the spindle to engage the spindle head and the device body with each other to freely restrict or release rotation of the device body with respect to the spindle head about the longitudinal axis of the spindle, spring means for urging the device body so that the fixing surface of the device body is pressed against the end surface of the spindle head with the engaging means ready for connection, fluid pressure means for generating a fluid pressure acting on the fixing surface of the device body against the spring force of the spring means so that connection of the engaging means is released, and transmission means, to transmit the rotation of the spindle to the device body by the fluid pressure of the fluid pressure means acting on the attachment surface of the device body.In the spindle fixing device according to the present invention, when the device body is rotated, the fluid pressure means can generate a fluid pressure acting on the fixing surface of the device body against the spring force of the spring members. Therefore, when the attachment surface of the jig body is attached to or detached from the end surface of the spindle head, the jig body can rotate in a stable position.Further, the engaging means may include fixed teeth disposed on a periphery of the end surface of the spindle head whose center is the longitudinal axis of the spindle, and movable teeth disposed on a periphery of the attachment surface of the device body having the same diameter as the periphery on which the fixed teeth are formed. Then, a desired number of fixed teeth and a desired number of movable teeth can be appropriately arranged, and it is easy to synchronize the fixed teeth and the movable teeth.Further, a central opening may be provided at the center of the circumference of the attachment surface of the device body on which the movable teeth are disposed, and a draw bolt may be inserted into an axial opening of the spindle to allow connection with a coupling rod, the draw bolt being inserted into the central opening such that the draw bolt can move in the axial direction, and an annular space being formed between the circumferential surface of the central opening and an outer surface of the draw bolt, an inner flange being disposed on the circumferential surface of the central opening, and an outer flange being disposed on the outer surface of the draw bolt, and the spring means comprising a compressed coil spring accommodated in the annular space and held between the outer flange and the inner flange. Then, the tension bolt and the compressed coil spring are effectively utilized, and the spring force can be effectively utilized as the urging means generated by the spring means.Moreover, a cylinder may be formed concentrically with the longitudinal axis of the spindle, and the fluid pressure means may include a piston accommodated in the cylinder such that an end of the piston protrudes from the cylinder so as to be able to come into contact with the attachment surface of the device body. Then, the fluid pressure of the fluid pressure means can effectively act on the spindle head.Further, a movable clamp member may be connected to the protruding end of the piston, and a fixed clamp member for clamping the movable clamp member may be disposed on the mounting surface of the apparatus body, so that according to the rotation of the apparatus body about the longitudinal axis of the spindle, the fixed clamp member is positioned in an unclamped position and in a clamping position relative to the movable clamp member, such that the fixed clamp member is free to move longitudinally in an unclamped position relative to the fixed clamp member, and the movable clamp member is engageable with the fixed clamp member from the apparatus body side in the clamping position. Then, the movable clamp part and the fixed clamp part can be clamped and released by utilizing the rotation of the apparatus body.Further, the transmission means may comprise a key disposed on the end surface of the spindle and a key groove formed on the attachment surface of the apparatus body, and the key may be engaged with the key groove. The transmission means can then be manufactured in a very simple construction.According to the present invention, the device body can be pressed by pressing means, and when the attachment surface of the device body is detachably attached to the end surface of the spindle head, the device body can rotate in a stable position. FIG. 1 is a vertical longitudinal sectional view showing a fixing device according to the present invention; FIGS. 2A and 2B are horizontal cross-sectional views taken along line II-II of FIG. 1 ; FIG. 3 is an explanatory diagram showing the operation of the apparatus; FIG. 4 is an explanatory diagram following FIG. 3 showing the operation of the apparatus; FIG. 5 is an explanatory diagram showing the operation of FIG. 4; and Fig. 6 is an explanatory diagram following Fig. 5 showing the operation of the apparatus.Fig. 1 essentially shows a spindle device 11 of a large, complex vertical machining machine suitable for performing machinings with a milling tool (not shown) directly connected to the spindle and a fastening device 12 for fastening a cutting tool to the spindle. In this embodiment, the fastening device 12 holds a turning tool B on the spindle.The spindle device 11 includes a vertical spindle 21 and a spindle head 22 that holds the spindle 21.The spindle 21 has a central opening 31. The lower end portion of the central opening 31 is formed by a downwardly inclined opening portion 32. The central opening 31 receives a coupling rod 33. At the lower end portion of the coupling rod 33, a clamping sleeve 34 is provided. Two drive keys 35 are fixed to a lower end surface of the spindle 21 on a periphery whose center is on a longitudinal axis of the spindle (see FIGS. 2A and 2B ). The two driving wedges 35 are fixed thereto at a regular interval in a circumferential direction. Note that the spindle 21, the coupling rod 33, the drive keys 35, and the like are formed like a conventional spindle that receives and rotates a conventional turning tool, or performs known processes for transmitting power to a turning tool by means of the drive key and the like when a fastener for a turning tool is attached.The lower end surface of the spindle head 22 is disposed at a level above the lower end surface of the spindle 21. Above the end face of the spindle head 22, a cylinder 41 is formed with an annular cross section concentric to the longitudinal axis of the spindle. A tubular piston 42 is inserted into the cylinder 41. The piston 42 includes a large-diameter upper piston portion 42 adisposed in the cylinder 41 and a small-diameter lower piston portion 42 bconnecting to a lower end of the upper piston portion 42 a. The lower piston portion 42 bpasses through a bottom wall of the cylinder 41 and protrudes downward from the lower end surface of the spindle head 22. The lower piston portion 42 bincludes the spindle 21.An upper opening 43 is disposed in a space above the upper piston portion 42a, and a lower opening 44 is disposed in an underlying space inside the cylinder 41. The upper opening 43 and the lower opening 44 penetrate the cylinder, respectively.A plurality of fixed teeth 45 are formed radially outward of the lower piston portion 42 bat a lower end surface of the spindle head 22. On the lower end surface of the lower piston portion 42b, a movable clamp member 46 formed horizontally in an annular shape is fixed concentrically with the longitudinal axis of the spindle.The fastening device 12 has a device body 51 from which a turning tool B protrudes in the radial direction with respect to the longitudinal axis of the spindle.An upper surface of the apparatus body 51 has an upwardly directed recess 52 which receives the lower end portion of the spindle 21 and the movable clamp member 46. A guide sleeve 53 is disposed at the center of the bottom surface of the recess 52. The guide sleeve 53 is inserted into the inclined opening portion 32, and the outer surface of the guide sleeve 53 has an upwardly inclined shape. A cylindrical guide hole 54 having a bottom is formed on an inner surface of the guide sleeve 53. A tension bolt 55 is held in the guide opening 54. A radially directed protrusion 55a clamped by the clamp sleeve 34 is formed at an upper end portion of the tension bolt 55. A vertical rod-shaped guide rod 55b is provided at a lower half of the draw bolt 55. The vertical rod-shaped guide rod 55b is inserted into the guide hole 54 so that the vertical rod-shaped guide rod 55b can freely slide up and down.A vertical cylindrical space 56 is formed between the peripheral surface of the guide hole 54 and the outer surface of the guide rod 55b. An inner flange 57 is disposed in the vicinity of the upper end of the circumferential surface of the guide hole 54. An outer flange 58 is disposed at a lower end portion of the outer surface of the guide rod 55 b. A compressed coil spring 59 is disposed in the annular space 56 such that the compressed coil spring 59 is held vertically between the inner flange 57 and the outer flange 58.On the outside of the guide sleeve 53, two key grooves 61 are formed at the bottom of the recess 52. The driving keys 35 are inserted into the two key grooves 61, respectively.On the outer edge of the upper surface of the device body 51, a plurality of movable teeth 62 are upwardly formed so as to oppose the fixed teeth 45.An annular fixed clamp member 63 is disposed on a slightly inner side of the movable teeth 62 on the circumferential surface of the recess 52. The annular fixed clamp 63 is disposed at a low level such that the annular fixed clamp 63 is disposed at a level below the movable clamp 46.FIGS. 2A and 2B show a relationship of the procedures among the fixed teeth 45, the movable teeth 62, the movable clamp part 46, and the fixed clamp part 63.The movable teeth 62 are arranged in a row at a regular pitch θ on a circumference whose center is the longitudinal axis of the spindle in a circumferential direction thereof. Although the fixed teeth 45 are not shown in these figures, the fixed teeth 45 have the same structure as the movable teeth 62, but are oppositely oriented in the vertical direction.On the outer edge of the movable clamp member 46, in a circumferential direction thereof, a plurality of outward claws 71 are arranged at a regular pitch 2θ. On the inner edge of the movable clamping part 63, in a circumferential direction thereof, a plurality of inward claws 72 are arranged at a regular pitch 2θ that is the same pitch as the pitch 2θ of the outward claws 71. The pitch 2θ of the outward pawls 71 and the inward pawls 72 is twice as large as the pitch θ of the movable teeth 62.In FIG. 2A, the fixed teeth 45 and the movable teeth 62 may be meshed with each other in the direction of the longitudinal axis of the spindle. An outward claw 71 is positioned between two adjacent inward claws 72. In this state, when the movable clamp part 46 is moved relative to the fixed clamp part 63 in the axial direction of the spindle, an outward claw 71 can pass between two inward claws 72. Accordingly, the fixed clamp part 63 and the movable clamp part 46 do not clamp. In other words, the movable clamp part 46 is in an unclamped position.The state shown in FIG. 2A changes to the state shown in FIG. 2B when the device body 51 is rotated and the fixed clamp part 63 is rotated by the pitch θ of the movable teeth 62. Even in this state, the fixed teeth 45 and the movable teeth 62 can engage with each other, but the fixed clamp part 63 and the movable clamp part 46 overlap in the axial direction of the spindle. When the movable clamp part 46 moves relative to the fixed clamp part 63 in the axial direction of the spindle, the inward claws 42 and the outward claws 71 clamp each other. The movable clamp member 46 is positioned in a clamping position.Referring to Figs. 3 to 6, the fastening operation of the fastening device 12 will be described.The device body 51 is conveyed to a location below the spindle device 11 by a tool exchanging device (not shown), and thereafter is moved upward by an upward stroke. FIG. 3 shows the device body 51 shortly before the device body 51 stops rising at its highest possible position in the upward stroke.The coupling rod 33 is positioned at its lowest possible position of the up / down stroke. The clamping sleeve 34 is open.Pressurized oil is supplied to the lower port 44 and the piston 42 is positioned at the highest possible position of its up / down stroke. On the other hand, the draw bolt 55 is drawn into the guide sleeve 53 by the force of the spring 59. The fixed clamp 63 is positioned at a level below the movable clamp 46. The phases of the fixed teeth 45 and the movable teeth 62 are such that they can be interlocked and the movable clamp member 46 is positioned in the unclamped position.Then, as shown in FIG. 4, the tool exchanging device further moves the device body 51 upward to lift the device body 51 to the highest possible position. The fixed teeth 45 and the movable teeth 62 mesh with each other. The movable clamp 46 is positioned at a level below the fixed clamp 62. There is a space between the lower surface of the recess 52 of the device body 51 and the lower surface of the movable clamp member 46.The guide sleeve 53 is inserted into the tapered hole 32. The coupling rod 33 is raised and the clamping sleeve 34 is closed.Accordingly, the tension sleeve 34 engages the projection 55a of the tension bolt 55 to prevent the lowering of the tension bolt 55. The keys 35 are inserted into the key slots 61.When the lower port 44 is opened to supply pressurized oil to the upper port 43, the piston 42 descends as shown in FIG. 5. The movable clamping part 46 and the piston 42 sink. Accordingly, the descending movable clamp member 46 comes into contact with and presses the bottom surface of the recess 52 of the jig body 51, the jig body 51 descends against the force of the spring 59, and the draw bolt 55 is pulled out of the guide sleeve 53. The connection between the fixed teeth 45 and the movable teeth 62 is released.Then, when the spindle 21 is rotated, this rotation is transmitted to the apparatus body 51 via the splines 35 and the splines 62. While the movable clamping part 46 presses the bottom surface of the recess 52 of the device body 51, the device body 51 is rotated by the pitch θ of the movable teeth 62. The movable clamp part 46 is placed in the clamping position.Finally, the upper port 46 is opened to supply pressurized oil to the lower port 44 so that the piston 42 rises as shown in FIG. 6. Accordingly, the fixed clamp member 63 and the movable clamp member 46 are engaged with each other, and the fluid pressure acting on the piston 42 is transmitted to the device body 51. This pressure connects the state of engagement between the fixed teeth 45 and the movable teeth 62, and thus machining can be performed with the turning tool B.In the state shown in FIG. 6, a gap is formed between the circumferential surface of the inclined opening portion 32 of the spindle 21 and the outer surface of the guide sleeve 53. if there were no gaps, both surfaces would collide, and the fluid pressure may not be sufficiently transmitted to the fixed teeth 45 and the movable teeth 62.The spindle fastening device according to the present invention is suitable for fastening a cutting device used as a machine tool to the spindle head.

Claims

A spindle fixing device comprising: a device body (51) having a fixing surface detachably fixed to an end surface of the spindle head (22); engaging means (45, 62, 42, 42a, 42b, 43, 44) for moving the device body (51) in an axial direction of the spindle (21) to engage the spindle head (22) and the device body (51) with each other so as to freely restrict or release the rotation of the device body (51) with respect to the spindle head (22) about the longitudinal axis of the spindle; spring means (59) for urging the device body (51) so as to press the fixing surface of the device body (51) against the end surface of the spindle head (22) with the engaging means (45, 62) ready for connection; Fluid pressure means (42, 42a, 42b) for generating a fluid pressure acting on the mounting surface of the apparatus body (51) against the spring force of the spring means (59) so as to release the connection of the engaging means (45, 62); and transmission means (35, 61) for transmitting the rotation of the spindle (21) to the apparatus body (51) by the fluid pressure of the fluid pressure means (42, 42a, 42b) acting on the mounting surface of the apparatus body (51).The spindle mounting device according to claim 1, characterized in that the engaging means (45, 62) comprises: fixed teeth (45) disposed on a periphery of the end surface of the spindle head (22) whose center is the longitudinal axis of the spindle (21); and movable teeth (62) disposed on a periphery of the mounting surface of the device body (51) having the same diameter as the periphery on which the fixed teeth (45) are formed.The spindle fastening device according to claim 1 or 2, characterized in that a central opening is provided at the center of the circumference of the fastening surface of the device body (51) on which the movable teeth (62) are disposed, and a draw bolt (55) is inserted into an axial opening (31) of the spindle (21) to allow connection with a coupling rod (33), the draw bolt (55) being inserted into the central opening such that the draw bolt (55) can move in the axial direction, and an annular space (56) is formed between the circumferential surface of the central opening and an outer surface of the draw bolt (55b), an inner flange (57) is disposed on the circumferential surface of the central opening, and an outer flange (58) is disposed on the outer surface of the draw bolt (55), and wherein the spring means (59) comprises a compressed coil spring (59) received in the annular space (56) and held between the outer flange (58) and the inner flange (57).A spindle mounting device according to claim 1, characterized in that a cylinder (41) is formed concentrically with the longitudinal axis of the spindle (21), and that the fluid pressure means (42, 42a, 42b) comprises a piston (42) accommodated in the cylinder (41) such that an end of the piston (42) protrudes from the cylinder (41) so as to be able to come into contact with the mounting surface of the device body (51).The spindle fixing device according to claim 4, characterized in that a movable clamping part (46) is connected to the protruding end of the piston (42), and a fixed clamping part (63) for clamping the movable clamping part (46) is disposed on the fixing surface of the device body (51), so that according to the rotation of the device body (51) about the longitudinal axis of the spindle (21), the fixed clamping part (63) is positioned in an unclamped position and in a clamping position relative to the movable clamping part (46), so that the fixed clamping part (63) can freely move longitudinally relative to the fixed clamping part (63) in an unclamped position, and the movable clamping part (46) can engage with the fixed clamping part (63) from the device body (51) side in the clamping position.The spindle fixing device according to claim 1, characterized in that the transmission means (35, 61) includes a key (35) disposed on the end surface of the spindle (21) and a key groove (61) formed on the fixing surface of the device body (51), and the key (35) can engage with the key groove (61).

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