Patent Publication Number: US-2019168326-A1

Title: Electrochemical machining apparatus for gear outline

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a machining apparatus, and particularly to an electrochemical machining apparatus for trimming the gear outline of the gears in a workpiece using electrochemical machining. 
     BACKGROUND OF THE INVENTION 
     Gears are the most important component in mechanical transmission mechanisms. Thanks to their advantages of high transmission efficiency, accurate transmission ratio, and wide applications, gears are applied extensively in automobiles, aerospace, ships, instruments, and meters. As the requirements in the hardness, strength, wear resistance, and lifetime of gears in mechanical transmission designs become increasingly stringent, hardened gears are adopted generally. 
     Trimming of gears is normally arranged after thermal treatment. After thermal treatment, the hardness of gears will increase. If trimming of gears is performed by the cutting method according to the prior art, due to the large cutting force and high cutting temperature, cutting tools will wear seriously and gears will deform on the surface. Thereby, it is not appropriate to trim high-hardness gears using the cutting method according to the prior art. If a computer numerical control (CNC) machine tool is used to trim high-hardness gears, the machining cost will increase. In addition, there will be hard-to-remove flashes and burrs on the surface of the gears. 
     Accordingly, to solve to above technical drawbacks as described above, the present invention provides an electrochemical machining apparatus for gear outline for trimming the gear outline of the gears in a workpiece. 
     SUMMARY 
     An objective of the present invention is to provide an electrochemical machining apparatus for gear outline, which adopts electrochemical machining to machine the gear outline of the gears in a workpiece. 
     Another objective of the present invention is to provide an electrochemical machining apparatus for gear outline, which adopts an alignment structure to align a plurality of teeth of the gears of a workpiece. Then the plurality of teeth of the workpiece may correspond to the cathode electrode, and the cathode electrode may perform electrochemical machining on the plurality of teeth and hence trimming the outline of the plurality of teeth. 
     The present invention discloses an electrochemical machining apparatus for gear outline, which comprises a base, a first moving mechanism, a cathode electrode, a gear alignment member, and a second moving mechanism. The first moving mechanism is disposed on the base. The cathode electrode is disposed at the first moving mechanism. The gear alignment member is disposed on the base and includes a plurality of alignment gears. The second moving mechanism is disposed on the base and connected with the gear alignment member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a stereoscopic diagram of the electrochemical machining apparatus according to an embodiment of the present invention; 
         FIG. 2A  shows a cross-sectional view of a partial structure of the electrochemical machining apparatus according to an embodiment of the present invention; 
         FIG. 2B  shows an enlarged view of the cross-sectional view of a partial structure in  FIG. 2A ; 
         FIG. 2C  shows an exploded view of a partial structure of the electrochemical machining apparatus according to an embodiment of the present invention; 
         FIG. 3  shows a schematic diagram of the gear alignment member of the electrochemical machining apparatus moving and projecting the contour alignment structure according to an embodiment of the present invention; 
         FIG. 4  shows a cross-sectional view of the workpiece according to an embodiment of the present invention; 
         FIG. 5  shows a schematic diagram of aligning the workpiece using the electrochemical machining apparatus according to an embodiment of the present invention; 
         FIG. 6  shows a schematic diagram of pressing the workpiece using the electrochemical machining apparatus according to an embodiment of the present invention; 
         FIG. 7A  shows a schematic diagram of moving the cathode electrode to enter the workpiece for trimming the tooth outline of the gear of the workpiece using the electrochemical machining apparatus according to an embodiment of the present invention; 
         FIG. 7B  shows a cross-sectional view of a partial structure in  FIG. 7A ; 
         FIG. 8  shows a block diagram of the control circuit according to an embodiment of the present invention; 
         FIG. 9A  shows a bottom view of the gear when the cathode electrode corresponds to the workpiece according to the present invention; and 
         FIG. 9B  shows a partially enlarged view of  FIG. 9A . 
     
    
    
     DETAILED DESCRIPTION 
     In order to make the structure and characteristics as well as the effectiveness of the present invention to be further understood and recognized, the detailed description of the present invention is provided as follows along with embodiments and accompanying figures. 
     Please refer to  FIG. 1 ,  FIG. 2A , and  FIG. 2B , which show a stereoscopic diagram, a cross-sectional view of a partial structure of the electrochemical machining apparatus according to an embodiment of the present invention and an enlarged view of the cross-sectional view of a partial structure in  FIG. 2A . As shown in the figures, the present invention provides an electrochemical machining apparatus  1 , which is used for performing electrochemical machining on the tooth outline of the gear W 1  of a workpiece W. The electrochemical machining apparatus  1  comprises a base B, a first moving mechanism M 1 , a cathode electrode E, a gear alignment member P 1 , and a second moving mechanism M 2 . The base B includes a body B 1  and a carrier B 2 . The carrier B 2  is disposed on the front side of the body B 1 . The body B 1  and the carrier B 2  are formed integrally. The carrier B 2  includes a first platform B 22  and a second platform B 24 . The second platform B 24  is locate above the first platform B 22  with a gap therebetween. The first moving mechanism M 1  is disposed on the body B 1  of the base B. The cathode electrode E is disposed at the first moving mechanism M 1 . The gear alignment member P 1  is disposed on the first platform B 22  of the carrier B 2  of the base B and includes a plurality of alignment teeth T, as shown in  FIG. 2C . Besides, the second moving mechanism M 2  is disposed on the base B and connected with the gear alignment member P 1 . 
     The first moving mechanism M 1  may include a linear moving mechanism M 12  and a rotating mechanism M 14 . The linear moving mechanism M 12  is disposed at the body B 1  of the base B. The rotating mechanism M 14  is disposed at the linear moving mechanism M 12 . The linear moving mechanism M 12  carries the rotating mechanism M 14  to perform linear movement. The cathode electrode E is connected to the rotating mechanism M 14 , which rotates the cathode electrode E. The linear moving mechanism M 12  may include a linear driving device M 124  and a linear moving member M 126 . The linear driving device M 124  may be a linear motor. The linear driving device M 124  is connected with the linear moving member M 126  for driving the linear moving member  126  to perform linear motion. 
     The rotating mechanism M 14  includes a spin driving device M 144 , which is disposed at the linear moving member M 126 . The spin driving device M 144  is further connected with the cathode electrode E for rotating the cathode electrode E. The spin driving device M 144  may be a spin motor. In addition, the linear moving mechanism M 12  may further include one or more sliding track SL 1  and one or more sliding member SL 2 . The sliding track SL 1  is disposed on both sides of the body B 1 ; the sliding member SL 2  is connected to both sides of the linear moving member M 126 . The sliding member SL 2  is located and slidable on the sliding track SL 1 . Moreover, the rotating mechanism M 14  may further include a connecting rod M 146 , which is connected with the spin driving device M 14  and passes through an alignment member M 148  for connecting to the cathode electrode E. The spin driving device M 144  spins the connecting rod M 146  for rotating the cathode electrode E. The alignment member M 148  is disposed on the second platform B 24  of the carrier B 2  for aligning the connecting rod M 146 . 
     As shown in  FIG. 2B  and  FIG. 2C , the electrochemical machining apparatus  1  may further include a contour alignment structure P 2  disposed on the first platform P 12  of the carrier B 2  of the base B. The gear alignment member P 1  is put around the contour alignment structure P 2  coaxially. The gear alignment member P 1  includes a plurality of first alignment parts P 12  spaced with one another. Each first alignment part P 12  includes the plurality of alignment teeth T. The gear alignment member P 1  may be hollow; and the plurality of first alignment parts P 12  may be blocks. 
     The contour alignment structure P 2  may include an alignment sleeve P 21  and an annular member P 25 . The alignment sleeve P 21  may be hollow and include a plurality of second alignment parts P 22 . Namely, the contour alignment structure P 2  includes the plurality of second alignment parts P 22 . The plurality of second alignment parts P 22  are located on the top of the alignment sleeve P 21  and spaced with one another. They may be staircase-shaped and include first staircase parts P 221  and second staircase parts P 223 . The alignment sleeve P 21  may include a plurality of recess parts P 23  located between the plurality of second alignment parts P 22 , respectively. The bottom surfaces of the plurality of recess parts P 23  are lower than the surfaces of the plurality of first staircase parts P 221 . The outer periphery of the plurality of second staircase parts P 223  may be curved. 
     The annular member P 25  includes a plurality of limiting parts P 26 , a plurality of recess parts P 27 , and a hollow part P 28 . The plurality of limiting parts P 26  and plurality of recess parts P 27  are all located on the inner side of the annular member P 25 . The plurality of limiting parts P 26  are space with one another and correspond to the plurality of recess parts P 23  of the alignment sleeve P 21 . Each limiting part P 26  includes a plurality of limiting teeth P 261  and is located on the surface of the limiting part P 26 . The plurality of limiting parts P 26  may be blocks. The plurality of recess parts P 27  are located between the plurality of limiting parts P 26 , respectively, and correspond to the plurality of first staircase parts P 221  of the alignment sleeve P 21 , respectively. The hollow part P 28  is located the central part of the annular member  25  and connects with the plurality of recess parts P 27 . The annular member P 25  may be put around the alignment sleeve P 21 . The plurality of limiting parts P 26  of the annular member P 25  are accommodated in the plurality of recess parts P 23  of the alignment sleeve P 21 . The plurality of first staircase parts P 221  of the plurality of second alignment parts P 22  of the alignment sleeve P 21  are accommodated in the plurality of recess parts P 27  of the annular member P 25 . The alignment sleeve P 21  and the annular member P 25  may be formed integrally to give the contour alignment structure P 2 . 
     The gear alignment member P 1  is put around the contour alignment structure P 2  coaxially. In addition, the plurality of first alignment parts P 12  of the gear alignment member P 1  are located between the plurality of second alignment parts P 22  of the contour alignment structure P 2 , respectively. Thereby, the plurality of first alignment parts P 12  of the gear alignment member P 1  and the plurality of second alignment parts P 22  of the contour alignment structure P 2  are interlaced and hence locating in an annular arrangement. Furthermore, the plurality of first alignment parts P 12  of the gear alignment member P 1  correspond to the plurality of limiting parts P 26  of the annular member P 25 , respectively, and the plurality of alignment teeth T of the plurality of first alignment parts P 12  may be wedged in the plurality of limiting teeth P 261  of the plurality of limiting parts P 26 . The plurality of alignment teeth T may move up and down along the plurality of limiting teeth P 261 . The plurality of limiting teeth P 261  may prevent the plurality of alignment teeth T from rotating and thus limiting the location of the plurality of alignment teeth T. The contour alignment structure P 2  may be a conductive electrode. 
     The gear alignment member P 1  and the contour alignment structure P 2  are both disposed on the carrier B 2  of the base B. The alignment sleeve P 21  of the contour alignment structure P 2  passes through the first platform B 22  from the bottom of the first platform B 22 . The bottom of the alignment sleeve P 211  is disposed against the bottom of the first platform B 22 . The annular member P 25  is put coaxially around the top of the alignment sleeve P 21 . The gear alignment member P 1  passes from the top of the first platform B 22  and goes down coaxially through the annular member P 25  and the alignment sleeve P 21 . 
     As shown in  FIG. 2B  and  FIG. 2C , a bottom lid P 2 B is disposed at the bottom of the alignment sleeve P 21  and includes a bottom sealant P 2 B 1  and a hole P 2 B 2 . The bottom sealant P 2 B 1  projects from the top surface of the bottom lid P 2 B; the hole P 2 B 2  penetrates the bottom lid P 2 B and the bottom sealant P 2 B 1 . A moving rod M 21  of the second moving mechanism M 2  passes through the hole P 2 B 2  and is connected to the bottom of the gear alignment member P 1  for driving the gear alignment member P 1  to move. The second moving mechanism M 2  may be a pneumatic cylinder or a hydraulic cylinder. 
     In addition, the gear alignment member P 1  includes a first channel P 1 F and a plurality of electrolyte inlets P 1 FI. The first channel P 1 F is located at the central region of the gear alignment member P 1 . The plurality of electrolyte inlets P 1 FI are located on the sidewall of the bottom of the gear alignment member P 1  and communicate with the first channel P 1 F. The contour alignment structure P 2  includes a second channel P 2 F and a plurality of electrolyte inlets P 21 . The second channel P 2 F is located at the central region of the alignment sleeve P 21 . The plurality of electrolyte inlets P 21  are located on the sidewall of the bottom of the alignment sleeve P 21  and communicate with the second channel P 2 F. The plurality of electrolyte inlets P 21  are connected with a first transport connector F 1  and a second transport connector F 2 , respectively. The gear alignment member P 1  is accommodated in the second channel P 2 F. Thereby, the plurality of electrolyte inlets P 1 FI and the first channel P 1 F of the gear alignment member P 1  communicate with the second channel P 2 F. 
     Please refer to  FIG. 3 , which shows a schematic diagram of the gear alignment member of the electrochemical machining apparatus moving and projecting the contour alignment structure according to an embodiment of the present invention. As shown in the figure, the second moving mechanism M 2  pushes the gear alignment member P 1 , enabling the plurality of first alignment parts P 12  of the gear alignment member P 1  to project from the alignment sleeve P 21  of the contour alignment structure P 2 . Hence, the plurality of alignment teeth T of the plurality of first alignment parts P 12  are higher than the plurality of second alignment parts P 22  of the alignment sleeve P 21 . As shown in  FIG. 4 , the workpiece W includes a gear part W 1 , which includes a plurality of inner teeth W 2 . The outer peripheries of the plurality of second staircase parts P 223  of the plurality of second alignment parts P 22  correspond to the inner periphery of the workpiece W. Thereby, as shown in  FIG. 5 , when the workpiece W is placed on the annular member P 25  of the contour alignment structure P 2  and the plurality of first staircase parts P 221  (as shown in  FIG. 3 ), the workpiece W is put around the plurality of second staircase parts P 223  of the contour alignment structure P 2  (as shown in  FIG. 3 ), making the workpiece W unable to move horizontally. Besides, the tooth shape of the plurality of alignment teeth T of the gear alignment member P 2  (as shown in  FIG. 3 ) corresponds to the tooth shape of the plurality of inner teeth W 2  of the workpiece W and hence the plurality of inner teeth W 2  of the workpiece W are wedged into the plurality of alignment teeth T of the gear alignment member P 1 . Thereby, the workpiece W is unable to rotate because the location of the plurality of inner teeth W 2  of the workpiece W is aligned. 
     Please refer to  FIG. 6 , which shows a schematic diagram of pressing the workpiece using the electrochemical machining apparatus according to an embodiment of the present invention. As shown in  FIG. 6 , the electrochemical machining apparatus  1  may further include a pressing mechanism PR disposed on the base B and opposing to the gear alignment member P 1  (as shown in  FIG. 3 ). The pressing mechanism PR includes a third moving mechanism M 3  and a pressing member PR 1 . The third moving mechanism M 3  is disposed on the second platform B 24  of the base B 2 ; the pressing member PR 1  is connected with the third moving mechanism M 3  and opposing to the gear alignment member P 1 . The third moving mechanism M 3  includes a first moving member M 32  and a second moving member M 34  disposed on both sides of the second platform B 24 , respectively, and connected with both sides of the pressing member PR 1 , respectively. The pressing member PR 1  includes an opening PR 2  corresponding to the workpiece W and the cathode electrode E. The first moving member M 32  and the second moving member M 34  may be pneumatic cylinder or a hydraulic cylinder. 
     The third moving mechanism M 3  pushes the pressing member PR 1  and thus pressing the workpiece W for avoiding the workpiece W from moving. In addition, the second moving mechanism M 2  drives the gear alignment member P 1  to move downward. Then the plurality of first alignment parts P 12  of the gear alignment member P 1  exit from the inside of the workpiece W and recover to the status shown in  FIG. 2B . The plurality of alignment teeth T of the plurality of first alignment parts P 12  are higher than the plurality of second alignment parts P 22  of the alignment sleeve P 21 . 
     Please refer to  FIGS. 1, 7A, and 7B , the first moving mechanism M 1  moves the cathode electrode E downward. The cathode electrode E passes through the opening PR 2  of the pressing member PR 1 , reaches the inside of the workpiece W, and corresponds to the plurality of inner teeth W 2  for trimming the outline of the plurality of inner teeth W 2  of the workpiece W. In other words, the outline of the cathode electrode E is just the outline of the tooth shape. 
     As shown in  FIG. 7B , the second channel P 2 F of the contour P 2  connects with the first channel P 1 F of the gear alignment member P 1 , and the first channel P 1 F is located at the central region P 1 C of the gear alignment member P 1 . Thereby, the electrolyte transported by the first transport connector F 1  and the second transport connector F 1  may pass along the second channel P 2 F and the first channel P 1 F and then inject to the plurality of inner teeth W 2  of the workpiece W. Besides, the cathode electrode E is coupled to the cathode of the power supply (not shown in the figure); the contour alignment structure P 2  is coupled to the anode of the power supply (not shown in the figure). It means that the workpiece W is coupled to the anode of the power supply. Thereby, the cathode electrode E may perform electrochemical machining on the plurality of inner teeth W 2  of the workpiece W for trimming the outline of the plurality of inner teeth W. 
     Please refer  FIG. 8 , which shows a block diagram of the control circuit according to an embodiment of the present invention. As shown in the figure, the electrochemical machining apparatus  1  further comprises a controller CTRL, which coupled to a sensor SOR, the linear moving mechanism M 12  and the rotating mechanism M 14  of the first moving mechanism M 1 , the second moving mechanism M 2 , the first moving member M 32  and the second moving member M 34  of the third moving mechanism M 3 . The controller CTRL controls the linear moving mechanism M 12 , the rotating mechanism M 14 , the second moving mechanism M 2 , the first moving member M 32 , and the second moving member M 34 . 
     The sensor SOR may be disposed on the base B and coupled to the contour alignment structure P 2  and the cathode electrode E for detecting the electrical status, for example, the current status, of the cathode electrode E and the workpiece W. Then the controller CTRL may control the rotating mechanism M 14  according to the electrical status. Before the electrochemical machining apparatus  1  starts to trim the plurality of inner teeth W 2  of the workpiece W, the controller CTRL controls the rotating mechanism M 14  to spin for aligning the relative position of the trimming teeth E 2  of the cathode electrode E and the plurality of inner teeth W. 
     As shown in  FIGS. 9A and 9B , the controller CTRL controls the rotating mechanism M 14  to spin clockwise so that the periphery E 21  of the trimming teeth E 2  of the cathode electrode E touches slightly the periphery W 21  of the inner teeth W 2 . At this moment, the sensor SOR may sense that the trimming teeth E 2  and the inner teeth W 2  are in short circuit and generate and transmit a sensing signal to the controller CTRL. Then the controller CTRL knows that the cathode electrode E and the workpiece W are in electrical short circuit. It controls the rotating mechanism M 14  to stop spinning clockwise. Instead, it enables the rotating mechanism M 14  to spin counterclockwise and records the angle at which the rotating mechanism M 14  spins counterclockwise until the sensor SOR senses another short circuit between the trimming teeth E 2  and the inner teeth W 2 . It means that the periphery E 22  of the trimming teeth E 2  touches slightly the periphery W 22  of the inner teeth W 2 . Then the controller CTRL controls the rotating mechanism M 14  to step spinning counterclockwise. The controller CTRL may deduce the gap between the trimming teeth E 2  and the inner teeth W 2  according to the recorded angle. Hence, it may control the rotating mechanism M 14  to spin clockwise for moving the trimming teeth E 2  to the central position between the periphery W 21  and periphery W 22  of the inner teeth W 2 . Accordingly, the distance between the periphery E 21  of the trimming teeth E 2  and the periphery W 21  of the inner teeth W 2  is equal to the distance between the periphery E 22  of the trimming teeth E 2  and the periphery W 22  of the inner teeth W 2 . Then the trimming accuracy may be improved. 
     To sum up, the present invention provides an electrochemical machining apparatus, which uses an electrochemical machining method for trimming the gear outline of the gear part of a workpiece. The electrochemical machining apparatus uses an angular alignment member to align the location of a plurality of teeth of the gear part. Then the plurality of teeth of the workpiece may correspond to the cathode electrode and the cathode electrode may perform electrochemical machining on the plurality of teeth and trimming the outline of the plurality of teeth. The electrochemical machining apparatus may trim workpiece with high hardness as well as avoiding flashes and burrs on the workpiece. In addition, the channel is disposed at the gear alignment member. The gear alignment member may be further disposed coaxially with the contour alignment structure. Thereby, the gear alignment member may combine with the contour alignment structure and the channel to form a compound structure. 
     Accordingly, the present invention conforms to the legal requirements owing to its novelty, nonobviousness, and utility. However, the foregoing description is only embodiments of the present invention, not used to limit the scope and range of the present invention. Those equivalent changes or modifications made according to the shape, structure, feature, or spirit described in the claims of the present invention are included in the appended claims of the present invention.