TWI894764B - Jig for gears - Google Patents

Abstract

A jig for gears includes a base and a fastening member. A top surface of the base is provided with a ring-shaped first protrusion for supporting a blank away from the base. A bottom surface of the fastening member is provided with a ring-shaped second protrusion. The fastening member is detachably coupled to the base while the second protrusion is aligned with the first protrusion to clamp the blank.

Description

Gear processing fixture

The present invention relates to a jig for fixing a workpiece, and particularly relates to a jig used in gear machining.

A gear is a structure with multiple tooth-like protrusions formed around a circular disc. The teeth of two gears interlock to drive each other, thereby transmitting power. Common gears are typically sheet-shaped, meaning the central disc and the outer teeth are roughly the same thickness. However, some gears, such as the one shown in Figure 8, have outer teeth that are thicker than the central disc. The outer teeth extend one thickness above and below the central disc along the disc's axis. The manufacturing method for this special gear shape differs from that of conventional gears, requiring the development of specialized jigs.

To address the aforementioned issues, the present invention provides a gear machining jig for securing a blank. The jig comprises: a base having a first annular flange formed vertically on its top surface. The first flange has a support surface for supporting the blank, and the height of the first flange is sufficient to allow the blank to separate from the base; and a fixed plate having a second annular flange extending downwardly from its bottom surface. The second flange has a pressure surface for pressing against the blank. The fixed plate is detachably connected to the base, with the second flange aligned vertically with the first flange.

Preferably, the fixing plate is provided with a through-hole and a plurality of pin holes, and the base plate is provided with a screw hole and a plurality of pins, the pins correspondingly extending into the pin holes, and a bolt passes through the through-hole and is locked into the screw hole.

Preferably, the peripheral surface of the fixed plate is provided with a plurality of recesses corresponding to the processing positions of the blank.

Preferably, the base has at least one limiting post on the outer side of the first flange, and the limiting post can extend between two adjacent teeth of the blank and abut against the two adjacent teeth.

Furthermore, the chassis is provided with at least one groove on the outer side of the first flange; the limiting post is provided on a limiting base, and the limiting base is detachably fixed in the groove.

Preferably, the chassis is provided with two such grooves that are positioned opposite to each other, and each groove is provided with a respective limiting base.

Preferably, the base is provided with at least one groove on the outer side of the first flange.

1: Chassis

101: Top

10: Screws

11: Bump

110: Top

12: First flange

13: Support surface

14: Positioning column

15: Screw hole

16: Pin

17: Groove

2: Fixed disk

20: Bottom

21: Second flange

22: Pressure surface

23: Perforation

24: Bolts

241: Head

25: concave part

26: Pin hole

3: Limit base

31: Limiting column

32: Screws

4: Blank

41: plate part

42: Ring-shaped processing section

421: Upper part

4211, 4212: Teeth

422: Lower part

43: Center hole

5: Workbench

50: Countertop

51: Top row

52: Bottom row

6: Gear

Figure 1 is a schematic, exploded perspective view of the jig used in the first gear processing step of the present invention; Figure 2 is a schematic, perspective view of the jig used in the first gear processing step of the present invention; Figure 3 is a schematic, cross-sectional view of the jig used in the first gear processing step of the present invention; Figure 4 is a schematic, exploded perspective view of the jig used in the second gear processing step of the present invention; Figure 5 is a schematic, three-dimensional view of the jig used in the second gear processing step of the present invention; Figure 6 is a schematic, cross-sectional view of the jig used in the second gear processing step of the present invention; Figure 7 is a schematic view of the present invention in use; and Figure 8 is a schematic view of a gear product processed using the jig of the present invention.

To produce the gear 6 shown in Figure 8, a two-stage machining process is required on a blank 4 (see Figure 1). The blank 4 has a disc-shaped disc portion 41 and an annular portion to be machined 42 surrounding the outer circumference. The thickness of the annular portion to be machined 42 is greater than that of the disc portion 41. The annular portion to be machined 42 includes an upper portion 421 and a lower portion 422 that protrude toward either side of the disc portion 41. The machining process begins with a first step, machining the upper portion 421 of the blank 4 to form it into the desired tooth shape (the upper half), followed by a second step, machining the lower portion 422 of the blank 4 to form it into the desired tooth shape (the lower half). Together, these two steps constitute the tooth profile of the final product. The present invention provides a jig suitable for the above two steps to fix the blank 4 during processing.

Referring to Figures 1 through 3 , a gear machining jig suitable for the first step described above is shown. It comprises a base plate 1 and a fixed plate 2. In this embodiment, the base plate 1 is generally circular and is secured to a table 50 (see Figure 7 ) via a plurality of screws 10 . The top surface 101 of the base plate 1 has a cylindrical raised portion 11 . Extending upward from the periphery of the raised portion 11 is a first, continuous, annular flange 12 circumscribing a top surface 110 of the raised portion 11 . The top end of the first flange 12 forms a supporting surface 13 for contacting and supporting the disc portion 41 of the blank 4. The height of the first flange 12 is sufficient to allow the disc portion 41 of the blank 4 to separate from the top surface 110 of the raised portion 11.

Continuing from the above, a positioning post 14 protrudes upward from the center of the top surface 110 of the raised portion 11 of the chassis 1. This allows the blank 4 to be positioned by passing through a center hole 43 of the blank 4 when placed on the chassis 1 and supported by the support surface 13. Furthermore, a screw hole 15 is provided at the center of the positioning post 14.

The fixing plate 2 has an outer diameter roughly equal to that of the raised portion 11 of the chassis 1. A second flange 21 extends downward from its bottom circumference in a continuous annular shape, surrounding a bottom surface 20 of the fixing plate 2. The bottom end of the second flange 21 forms a pressing surface 22 for contacting and pressing against the blank 4. A through-hole 23 is provided in the center of the fixing plate 2. After the fixing plate 2 is superimposed on the blank 4, a bolt 24 is passed through the through-hole 23 and screwed into the screw hole 15 of the chassis 1. The head 241 of the bolt 24 then applies downward pressure, pressing the fixing plate 2 downward against the blank 4, thereby securing the blank 4 to the chassis 1.

The fixing plate 2 presses the blank 4 downward onto the base plate 1. Referring to FIG3 , the base plate 1 forms a concave shape on the top surface 110 of the raised portion 11 based on the first flange 12. On the other hand, the fixing plate 2 forms a concave shape on the bottom surface 20 based on the second flange 21. Since the first flange 12 and the second flange 21 are similar in shape and outer diameter, the base plate 1 forms a concave shape on the top surface 110 of the raised portion 11. The surfaces of the base plate 1 are approximately equal, forming a vertical alignment between the two. Consequently, the disc portion 41 of the blank 4 is clamped and secured by the first flange 12 and the second flange 21. A gap G1 is formed between a bottom surface of the disc portion 41 and the top surface 110 of the raised portion 11, while another gap G2 is formed between a top surface of the disc portion 41 and the bottom surface 20 of the fixed plate 2. In other words, the base plate 1 contacts the blank 4 only with the support surface 13 of the first flange 12, while the fixed plate 2 contacts the blank 4 only with the pressure surface 22 of the second flange 21. Therefore, if the blank 4 has tolerances, compression deformation can be avoided during clamping and securing, even with the small contact area. However, the areas of the support surface 13 and the pressure surface 22 should not be too large to avoid the aforementioned loss of compression deformation. Furthermore, the areas of the support surface 13 and the pressure surface 22 should not be too small to avoid excessive pressure concentration, which would damage the surface of the blank 4.

After the blank 4 is fixed to the chassis 1 using the fixed plate 2, the disc portion 41 of the blank 4 is tightly clamped between the second flange 21 of the fixed plate 2 and the first flange 12 of the chassis 1. Since the outer diameter of the fixed plate 2 is smaller than the outer diameter of the blank 4, the annular portion to be processed 42 of the blank 4 is exposed outside the fixed plate 2. At this time, milling processing can be started on the upper portion 421 of the annular portion to be processed 42 of the blank 4 to form the required tooth-shaped upper half. In this embodiment, the fixed plate 2 is provided with a plurality of recesses 25 on its circumference corresponding to the processing locations of the annular portion 42 to be processed on the blank 4. This provides clearance for the processing tool to prevent the tool from striking and damaging the fixed plate 2. Since the positions of the recesses 25 must correspond to the processing locations, and therefore the fixed plate 2 must be directional for assembly, two pins 16 are positioned near the screw holes 15 of the base plate 1, and two pin holes 26 are provided near the through-holes 23 of the fixed plate 2. Consequently, by aligning the pin holes 26 with the pins 16 during assembly, the recesses 25 are precisely aligned with the processing locations, resulting in rapid assembly.

Figures 4 to 6 illustrate a gear machining jig suitable for the second step described above. Its structure is essentially the same as the jig used in the first step, comprising components such as a base plate 1 and a fixed plate 2. The base plate 1 is provided with a first flange 12 similar to the aforementioned features, and the fixed plate 2 is provided with a second flange 21 similar to the aforementioned features. When the fixed plate 2 is fastened to the base plate 1 by bolts 24 to secure the blank 4, the blank 4 is still only contacted and clamped by the first flange 12 and the second flange 21, as described above.

As a jig suitable for the second process, since the upper portion 421 of the blank 4 has been formed into a tooth shape and turned over to face downward toward the chassis 1, to prevent the blank 4 from shifting due to vibration during the machining of the lower portion 422, the chassis 1 can be equipped with at least one limiting post 31 on the outer side of the first flange 12. As shown in Figure 5, the limiting post 31 can extend between two adjacent teeth 4211 and 4212 on the upper portion 421 of the blank 4 and abut against them. By positioning the limiting post 31 between the two adjacent teeth 4211 and 4212, the blank 4 has no space for vibration and shifting, thereby ensuring machining accuracy.

In this embodiment, referring to Figure 4 , the aforementioned limiting post 31 is mounted on a limiting base 3 , which is removably secured to a groove 17 in the chassis 1 via screws 32 . The number of limiting posts 31 is not limited; they only need to be located between two adjacent teeth. Therefore, in this embodiment, the groove 17 and the limiting base 3 are each two in number, located on opposite sides of the chassis 1 . These two limiting posts 31 securely secure the blank 4 to the chassis 1 .

The jigs described above are suitable for the first and second steps. Although they are used in different steps, their basic function of securing the blank 4 is the same. Therefore, only one set of the aforementioned base plate 1 and fixed plate 2 is required as the basic components, with two stopper bases 3 with stopper posts 31 as optional components. When the first step is required, the base plate 1 and fixed plate 2 are used to secure the blank 4. When the second step is required, two more stopper bases 3 are added and assembled onto the base plate 1 to secure the blank 4. In other words, the jig provided by the present invention can be used in two different gear processing steps, thus providing versatility.

Based on the aforementioned versatility, a further example of use can be derived, as shown in Figure 7. Multiple jig assemblies, consisting of base plates 1 and fixed plates 2, are installed in the upper row 51 of a workbench 5 to secure blanks awaiting the first processing step. A corresponding number of jig assemblies, consisting of base plates 1, fixed plates 2, and retaining bases 3, are installed in the lower row 52 to secure blanks that have completed the first processing step and are awaiting the second processing step. With this arrangement, after a blank 4 completes the first processing step on the upper row 51 jigs, it rotates to the lower row 52 jigs for the second processing step, while the upper row 51 jigs are reloaded for further processing. This allows multiple processing steps (including the first and second processing steps) to be performed simultaneously, improving work efficiency.

However, the above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Any substitution of equivalent components should still fall within the scope of the present invention.

In summary, those skilled in the art will understand that this invention can indeed achieve the aforementioned objectives and complies with the provisions of the Patent Law, and therefore, an application is filed in accordance with the law.

1: Base 101: Top 10: Screw 11: Raised portion 110: Top 12: First flange 13: Support surface 14: Positioning column 15: Screw hole 16: Pin 17: Groove 2: Fixed plate 21: Second flange 22: Pressure surface 23: Through hole 24: Bolt 241: Head 25: Recess 26: Pin hole 4: Base 41: Plate 42: Annular portion to be processed 421: Upper portion 422: Lower portion 43: Center hole

Claims (10)

A gear machining jig is used to secure a blank, the blank comprising a disc portion and an annular portion to be machined formed around the disc portion. The gear machining jig comprises: A base having an upwardly protruding portion, the protruding portion comprising a top surface and a first flange formed around the top surface and extending upward, the first flange being used to support a bottom surface of the disc portion of the blank; and A fixed plate includes a bottom surface and a second flange formed around the bottom surface and extending downward, the second flange being configured to press against a top surface of the plate portion of the blank. The fixed plate is removably connected to the base plate and has an outer diameter smaller than that of the blank. When the fixed plate presses against the top surface of the plate portion of the blank, the plate portion is tightly clamped between the second flange of the fixed plate and the first flange of the base plate, and the annular portion to be processed of the blank is located outside the fixed plate. As described in claim 1, the gear processing jig, wherein the fixed plate is provided with a through hole and a plurality of pin holes, the base plate is provided with a screw hole and a plurality of pins, the pins extend into the pin holes accordingly, and a bolt passes through the through hole and is locked into the screw hole. A gear processing jig as described in claim 1, wherein the peripheral surface of the fixed plate is provided with a plurality of recesses corresponding to the processing positions of the annular portion to be processed of the blank. As described in claim 1, the gear processing jig has at least one limiting column on the outer side of the first flange, and the limiting column can extend between two adjacent teeth of the blank and abut against the two adjacent teeth. As described in claim 4, the gear processing jig is provided with at least one groove on the outer side of the first flange of the chassis; the limiting column is provided on a limiting base, and the limiting base is detachably fixed in the groove. As described in claim 5, the gear processing jig is provided with two grooves on the chassis and the grooves are positioned opposite to each other, and each groove is provided with a limiting base. The gear processing jig as described in claim 1, wherein the base is provided with at least one groove on the outer side of the first flange. A gear processing jig as described in claim 1, wherein when the fixed plate presses against the top surface of the disk portion of the blank, the second flange of the fixed plate is aligned vertically with the first flange of the base plate, and a gap is formed between the bottom surface of the fixed plate and the top surface of the disk portion, and another gap is formed between the top surface of the base plate and the bottom surface of the disk portion. A jig assembly comprises: a workbench having a tabletop; a gear machining jig for a first process, which is similar to the gear machining jig described in claim 1, 2, 3, 7, or 8, wherein the base of the gear machining jig for the first process is fixed to the tabletop; and a gear machining jig for a second process, which is similar to the gear machining jig described in claim 1, 2, 3, 7, or 8, wherein the base of the gear machining jig for the second process is fixed to the tabletop. As described in claim 9, the chassis of the gear processing jig of the second process has at least one limiting column on the outer side of the first flange, and the limiting column can extend between two adjacent teeth of the blank and abut against the two adjacent teeth.