JP6528392B2 - Processing device - Google Patents

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a processing apparatus, and more particularly to a processing apparatus that performs machining on a workpiece held on a fixed base.

  When manufacturing a metal product through welding, a weld bead is formed on the weld. The generated weld bead is often removed by cutting, grinding or the like for the purpose of avoiding interference with other members.

  For example, when manufacturing an axle housing used to accommodate a rear axle of a large vehicle such as a truck, as described in Patent Documents 1 and 2, a main body divided into two parts is formed While joining by welding, another member called a triangular plate is attached by welding (see FIG. 2). Thereafter, the weld bead is removed by cutting at the weld portion of the joint portion of the main body portion and the attachment portion of the triangular plate.

Japanese Patent Application Laid-Open No. 7-328765 JP, 2010-247765, A

  In the case of cutting a projection such as a weld bead in a workpiece made of metal as described above, in order to accurately cut the portion where the projection is formed, the workpiece is installed on a fixing base It is required that the vibration (chatter vibration) generated during cutting between the workpiece and the cutting tool be minimized as much as possible. If chatter vibration occurs, there is a possibility that the accuracy of processing may be reduced, or the components of the processing apparatus such as a cutting tool may be damaged. When machining is performed by moving the tool with respect to the workpiece, such as grinding and cutting, as well as cutting, the vibration of the workpiece often affects the processing accuracy.

  In fixing a workpiece, conventionally, the workpiece is placed on a fixing table, and a holder such as a clamp device or a chuck device fixed to the fixing table is used to form the workpiece including both ends. A plurality of locations were held down from above to the fixed base. However, in this case, it has been difficult to sufficiently suppress the vibration of the workpiece during processing.

  The problem to be solved by the present invention is to provide a processing device capable of reducing the vibration generated between a workpiece and a tool during processing in a processing device that performs machining.

  In order to solve the above-mentioned subject, the processing device concerning the present invention holds in the state where the long worklike object consisting of metal material was bent along the long axis on a fixed stand, and carries out machining Make it a gist.

  Here, the processing apparatus holds the workpiece at a portion between the pair of end holders that holds the workpiece at mutually separated portions and the pair of end holders. Preferably, the pair of end holders and the halfway holder bend the workpiece by applying mutually opposite forces to the workpiece. .

  In this case, the pair of end holders may apply an upward force to the workpiece, and the halfway holders may apply a downward force to the workpiece.

  Further, the processing apparatus is a processing apparatus for processing a workpiece having a plate-like portion at a midway portion, and the halfway holder holds the plate-like portion of the workpiece between the fixture and the fixture. It is good if it is a clamp apparatus which clamps and holds.

  The tool may be a cutting tool.

  According to the processing apparatus according to the invention, since the workpiece is held in a bent state, a reaction force in the direction opposite to the bending direction is generated on the workpiece. The balance between the external force applied to deflect the workpiece and the reaction force allows the workpiece in the bent state to be stably held. As a result, even if the tool moves in contact with the surface of the workpiece during machining, the workpiece is less likely to vibrate.

  Here, the processing apparatus comprises a pair of end holders for holding the workpiece at mutually separated portions, and a halfway holder for holding the workpiece at a portion between the pair of end holders. , And when a pair of end holders and a midway holder bend a workpiece by applying mutually opposing forces to the workpiece, the workpiece is effectively processed. Can be bent and held stably.

  In this case, according to a configuration in which the pair of end holders apply a force directed upward to the workpiece, and the halfway holder applies a force directed downward to the workpiece, the workpiece is processed from above the tool. Vibration in the vertical direction can be effectively suppressed when processing is performed on the

  Furthermore, in the case where the processing apparatus is to process a workpiece having a plate-like portion at a midway portion, the midway holding tool clamps the plate-like portion of the workpiece to be held between it and the fixing base. According to the configuration of the apparatus, since the midway portion of the object to be processed can be firmly pressed against the fixing base and fixed, vibration during processing can be effectively prevented.

  In addition, when the tool is a cutting tool, in general, vibration is often applied to the workpiece during cutting, but this vibration can be obtained by bending and holding the workpiece as described above. Can be effectively suppressed and high processing accuracy can be obtained.

It is a perspective view showing the cutting device concerning one embodiment of the present invention. The said cutting device WHEREIN: It is an enlarged view which shows the to-be-processed object vicinity. It is a figure which expands and shows near the trunk part. In the figure, a part of the wall surface in front of the body is cut away and displayed. It is explanatory drawing which shows the bending of a to-be-processed object, (a) is showing the case where (b) bends a middle part upwards, when bending a middle part downwards. It is a figure which shows the measurement position of deflection amount in an Example. It is a figure which shows the measurement result of deflection amount.

  Hereinafter, a processing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Outline of cutting device]
The outline of the cutting apparatus 1 is shown to FIGS. 1-3 as a processing apparatus concerning one Embodiment of this invention. The cutting device 1 performs cutting on the surface of the workpiece 5 installed on the fixed base 3.

  The fixing base 3 is provided with a holder 4 including a pair of end holders 41 and a set of four midway holders 42. Although the detail of the holder 4 is mentioned later, it plays a role which hold | maintains stably the to-be-processed object 5 mounted in the fixed stand 3. FIG.

  The cutting device 1 has two robot arms 10a and 10b. Each of the robot arms 10a and 10b has six axes, and each axis is driven by a servomotor (11 or the like).

  A spindle motor 12 is attached to the tip of each of the two robot arms 10a and 10b, and a cutting tool 13 such as a face mill cutter is coupled to an output shaft of each spindle motor 12. In the two robot arms 10a and 10b, the first robot arm 10a cuts the right half area of the workpiece 5, and the second robot arm 10b cuts the left half area of the workpiece 5 Thus, depending on the respective movable range, different regions of the workpiece 5 can be cut and the entire region of the workpiece 5 can be cut in cooperation.

  Furthermore, in the present cutting device 1, the shape measuring device 14 is disposed adjacent to the spindle motor 12 at the tip of one of the two robot arms 10a and 10b (the first robot arm 10a in FIG. 1). It may be attached. The shape measuring device 14 measures the shape of the metal surface by optical measurement, for example, emits a linear laser beam to the surface of the workpiece 5 and measures the distance on a two-dimensional surface by the light cutting method. Can be exemplified. The cutting device 1 is further provided with a control unit (not shown) that controls the motions of the robot arms 10a and 10b, the rotation of the spindle motor 12, and the measurement by the shape measuring device 14.

[Workpiece]
The workpiece 5 to be cut using the cutting apparatus 1 according to the present embodiment has the projections 54 to be removed, the central portion can be fixed by the clamp device, and both ends can be pushed up It may be anything as long as it is a long object made of a metal material. The workpiece 5 may have a cylindrical portion partially or entirely. As the projections 54 to be removed, weld beads, so-called burrs, distortion of material, etc. can be exemplified.

  Here, the axle housing 5 is treated as an example of a workpiece. The axle housing 5 is used for a rear axle portion or the like of a large vehicle such as a truck, and accommodates an axle, a differential gear, and the like. As shown in FIG. 2, the axle housing 5 has a body 51 and a cylindrical portion 52 as a main body. The body portion 51 is formed by bending a steel plate into a semi-cylindrical shape (a substantially U-shaped cross section or a substantially U-shaped cross section) and bulging in a substantially annular shape, and accommodates the differential gear. Both surfaces of the body portion 51 are plate-like end faces 51 a having a substantially annular shape, and the edge 51 b of the steel plate is exposed inside the annular shape. And the hollow cylindrical part 52 by which an axle shaft is penetrated is formed in the radial direction both sides of the trunk | drum 51. As shown in FIG. A substantially triangular triangular plate 53 is attached to a space formed between the body 51 and the cylindrical portion 52.

  The body of such an axle housing 5 is manufactured from two separate parts. That is, by manufacturing two divided members in which the annular shape of the body portion 51 and the cylindrical shape of the cylindrical portion 52 are divided in half, and by welding the end edges of the two divided members in the cylindrical portion 52, A main body is formed. Thereafter, the triangular plate 53 is disposed at a portion between the trunk portion 51 and the cylindrical portion 52, and the portion between the main body portion and the triangular plate 53 is welded.

  The axle housing 5 thus formed has a weld bead 54 at the junction of the two split members and in the region between the body and the triangular plate 53. These weld beads 54 need to be removed as flatly as possible from the viewpoint of preventing interference with members attached to the axle housing 5 in a later step. Then, these welding beads 54 are cut using cutting device 1 concerning this embodiment.

[Arrangement of holder and holding of workpiece]
Here, details of the holder 4 for holding the workpiece 5 on the fixing base 3 will be described. As described above, the holder 4 is composed of a pair of end holders 41 and a pair of halfway holders 42.

  The end holder 41 is fixed on the fixed base 3 at a position where the end of the cylindrical portion 52 of the axle housing 5 which is a workpiece is disposed. Each end holder 41 has an end holding recess 41 a at the top. The end holding recess 41 a has a concave shape cut into a curved shape or a substantially V-shape which is approximately the same as or larger than a part of the outer shape of the cylindrical portion 52 of the axle housing 5. The cylindrical portion 52 can be placed in contact with it. The height of the end holding recess 41 a from the fixing stand 3 is determined so as to push up the cylindrical portion 52 of the axle housing 5 placed on the fixing stand 3. In addition, in order to mount the trunk | drum 51 of an axle housing suitably, the level | step-difference part 31 which became higher than the surface to which the edge part holding tool 41 is fixed is provided in the fixing base 3. FIG.

  Each pair of midway holders 42 comprises a clamping device, in particular a swing clamp. Each of the midway holding members 42 has a base 42 a fixed on the fixing base 3 at a position inside the annular shape of the trunk portion 51 of the axle housing 5. Then, an end edge 51 b of one end face 51 a of the barrel 51 of the axle housing 5 is pressed against the fixing stand 3 and held by the pressing portion 42 b connected to the base 42 a so as to adjust the distance. The four midway holding members 42 are arranged substantially axially symmetrical with respect to the center of the trunk 51.

  The axle housing 5 placed on the fixed base 3 is held in a state where the distal end of the cylindrical portion 52 at both ends is applied with an upward force by the end holder 41. Then, the midway trunk portion 51 is held by the midway holder 42 in a state where a force is applied downward. As described above, the force is applied to the axle housing 5 in the up and down direction by the end holder 41 and the midway holder 42, so that the end of the axle housing 5 is bent upward and the middle part is bent downward (curved State). The deflection is shown extremely as shown in FIG. 4 (a).

  In the axle housing 5 thus bent, a reaction force is exerted by the elasticity of the metal material (steel sheet). As shown in FIG. 4A, the reaction force Fr works in the direction opposite to the bending direction of the axle housing 5, that is, in the direction of lifting the midway portion upward. The magnitude of the reaction force Fr is balanced with the external force Fe applied to the axle housing 5 by the end holder 41 and the halfway holder 42.

  As described above, the axle housing 5 is stably held at a predetermined position on the fixing base 3 by balancing the external force Fe for bending the axle housing 5 and the reaction force Fr exerted in the opposite direction to the external force Fe. . As a result, when the cutting tool 13 is brought into contact with the surface of the axle housing 5 from above to perform cutting, even if the cutting tool 13 rotates, the axle housing 5 hardly vibrates (chatter vibration). As a result, it is possible to suppress a decrease in processing accuracy due to the vibration of the axle housing 5. For example, when cutting the weld bead 54 on the surface of the axle housing 5, the axle housing 5 is simply held down from above and fixed, or the both ends of the cylindrical portion 52 are pressed toward the center A high surface smoothness can be achieved compared to the case etc.

  The direction in which the workpiece including the axle housing 5 is bent is not limited to bending the end upward and the middle downward as described above, but the cutting tool 13 contacts the workpiece 5 By bending along the direction in which the workpiece 5 is bent, vibration of the workpiece 5 along the direction of the movement of the cutting tool 13 can be effectively suppressed. That is, when the cutting tool 13 cuts from above the workpiece 5 as described above, the vibration in the vertical direction accompanying the cutting is effectively made by bending the axle housing 5 along the vertical direction. It can be suppressed.

  As bending in the vertical direction, there are considered cases of bending in the direction of lowering the middle portion as shown in FIG. 4A and cases of bending in the direction of raising the middle portion as shown in FIG. 4B. Also in the case, the effect of suppressing the vibration in the vertical direction can be obtained. In the case where the workpiece has cylindrical portions 52 at both ends as in the axle housing 5 and a plate-like portion such as the end face 51a at the middle portion, as described above, It is excellent in the stability of holding if it is made to bend in the direction which raises the both ends and lowers the middle part. This is because the plate-like portion present in the middle portion such as the end face 51a can be easily held between the fixing stand 3 and the holding stand 3 by the clamp device, and can be held while being pressed against the fixing stand 3. Although it is relatively difficult to hold the end by holding it toward the fixed base 3 by a clamp device or the like, it is placed and pushed up from below using a holder such as the end holder 41 described above. It is because it is easy to hold.

  As described above, by fixing the workpiece 5 using the reaction force, a smaller external force is applied as compared to the case where the end portion or mid-portion of the workpiece 5 is simply pressed from above onto the fixing base and fixed. Only by that, the vibration of the workpiece 5 at the time of processing can be effectively suppressed. For this reason, the holder 4 of a simple structure can be used for fixation of the to-be-processed object 5. FIG. In particular, when a swing clamp is used as a midway holder 42 for fixing the axle housing 5, if the swing clamp is disposed in a well-balanced manner inside the body 51 as described above, a pneumatic clamp is used instead of a hydraulic clamp. The vibration at the time of cutting the weld bead 54 with the cutting tool 13 can be sufficiently suppressed by using (see the following example). The pneumatic swing clamp is inferior in output as compared with the hydraulic swing clamp, but has a simple configuration and is excellent in handleability.

  The amount of bending of the workpiece 5 may be selected as appropriate as long as sufficient reaction force is generated and the bending can be eliminated after the holder 4 is removed. For example, when the workpiece 5 is the axle housing 5 made of a steel plate, the amount of deflection is preferably about 0.1 to 0.3% of the total length at the maximum location. Further, the specific structure of the end holder 41 and the midway holder 42 or the installation site is such that the pair of end holders 41 are installed separately from each other, and the middle holder between the end holders 41 is installed. As long as it is possible to apply mutually opposing forces to the work pieces 5 by installing 42, it may be appropriately selected according to the shape of the work pieces 5, the direction of bending, and the like.

  The amount of bending when the axle housing was bent using the end holder and the midway holder and the influence on the processing accuracy were actually examined.

(Example)
Specifically, the axle housing 5 has a total length of 1330 mm, an outer diameter of 395 mm of the body, an outer diameter of 120 mm of the cylindrical portion, a thickness of the body (distance between outer wall surfaces of both end faces) 124 mm, and a thickness of 8 mm of steel plate It used as a to-be-processed object. As shown in FIG. 5, while pushing up one end of the cylindrical portion 52 of the axle housing 5 with a force of 135 kgf using the end holder 41, four places of the trunk 51 are obtained using the swing clamp 42. Each was pressed onto the fixed base with a force of 630 kgf, and the axle housing 5 was flexed. Under the present circumstances, the fulcrum 7 was provided in the position of 140 mm from the center of the trunk | drum 51, and it fixed with respect to the fixed stand.

  Then, dial gauges were disposed at positions 245 mm, 365 mm, and 485 mm (280 mm, 160 mm, and 40 mm from the end of the cylindrical portion) outside the fulcrum. Thus, the amount of displacement of each position due to deflection was measured, and it was set as the amount of deflection.

  FIG. 6 shows the amount of deflection at each measured position. According to this, it can be seen that a maximum of 1.5 mm of deflection occurs. Also, as shown by the approximate curve in the figure, the amount of deflection is proportional to the distance from the fulcrum. Thus, as described above, it can be seen that the entire axle housing can be uniformly bent by pushing up the end and pushing down the barrel.

  Further, in the state of being bent as described above, cutting of the weld bead was performed from above using a face mill cutter attached to the robot arm. After cutting, the surface roughness of the cut portion was evaluated using a surface roughness standard piece. As a result, the surface roughness (Rmax) was estimated to be equivalent to 12S.

(Comparative example)
The axle housing 5 similar to that used in the above embodiment was fixed on a fixed base without bending. Specifically, tapered center cones were respectively inserted into the hollow portions at both ends of the cylindrical portion 52 of the axle housing 5 from the tip end side, and were pressed toward the center by a force of 1250 kgf. Further, using a push-up jig provided on the fixed base, the lower end surface 51a of the body portion 51 was pushed up with a force of 780 kgf, and leveling was performed. In this state, the welding bead was cut from above as in the case of the example. The surface roughness (Rmax) of the cut part was estimated to be equivalent to 50 to 100S.

  As described above, it was found that, by bending and holding the axle housing, a smooth surface can be obtained by cutting as compared with the case of holding without bending.

  As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of this invention. For example, the processing device according to the present invention is not limited to a cutting device, and can be any processing device that performs any machining such as polishing, cutting, etc. As described above, the workpiece is bent and held. Thus, vibration during processing can be suppressed.

DESCRIPTION OF SYMBOLS 1 Cutting device 10a, 10b Robot arm 11 Servomotor 12 Spindle motor 13 Cutting tool 14 Shape measuring device 3 Fixing base 4 Holder 41 End holder 41a End holding recess 42 Midway holder (swing clamp)
5 Axle housing (workpiece)
51 body 51a end face 51b edge 52 cylindrical portion 53 triangular plate 54 weld bead (protrusion)
Fe external force Fr reaction force

Claims (5)

In a processing apparatus for cutting a long workpiece made of a metal material, having a midway portion and an end portion,
The processing device is
A pair of end holders for mounting and holding the ends of the workpiece at mutually separated locations;
And a midway holder for pressing and holding the midway portion of the workpiece at a position between the pair of end holders.
The pair of end holders applies an upward force to the workpiece, and the halfway holder applies a downward force to the workpiece to form the pair of end holders. And the halfway holder apply mutually opposing forces to the workpiece,
The cutting tool is held from above to below with respect to the workpiece while holding the workpiece in a state where the entire workpiece is bent up and down uniformly along the long axis on the fixing base. A processing apparatus characterized in that it is brought into contact and moved with respect to the workpiece to cut a portion including the midway portion . The processing apparatus is a processing apparatus for cutting a workpiece having a plate-like portion at the midway portion,
The processing apparatus according to claim 1, wherein the halfway holder is a clamp device that holds the plate-like portion of the workpiece between the fixing stand and the holding unit. The said cutting tool is a cutting tool which cuts in the whole area along the long axis of the said to-be-processed object, The processing apparatus of Claim 1 or 2 characterized by the above-mentioned. The workpiece has a toroidally expanded body portion,
Both sides of the body portion are end faces having an annular shape,
The processing apparatus according to any one of claims 1 to 3, wherein cylindrical parts are provided on both sides in the radial direction of the body part. A plurality of said midway holding members are arranged axially symmetrical with respect to the center of said barrel in the inside of said annular shape of said barrel, and one of said end faces is said midway of said workpiece at one of said end faces. The processing apparatus according to claim 4, wherein the portion is pressed toward the fixing base, and the cutting tool contacts the other of the end faces from above to perform the machining.

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