JP2011190923A - Sintered-metal sprocket having mark on side surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a three-dimensional mark formed on the side surface of a sintered-metal sprocket by recessing the side surface in such a shape allowing positioning without requiring additional cost for imparting the mark. <P>SOLUTION: A sintered-metal sprocket has a cylindrical or conical flange at its upper part, a gear at its lower part, and a mark (5) on the side surface (6) of the cylindrical part or conical part. The mark (5) is in parallel with the axial center of a component. The mark is configured such that at least its one end is cut through the end surface (8) of the component and a protrusion (12) corresponding to the gear is provided inside the mark. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a sintered metal sprocket having a cylindrical or conical side surface provided with a mark that does not require machining and can be positioned by sizing. The mark said here is a three-dimensional mark formed by denting the side surface.

  Sintered metal sprockets that are mounted on a rotating shaft, especially sintered sprockets for power transmission used in engine drive systems, have a mark for confirming the assembly position at a location visible from the outside of the surface. A mark such as a timing mark detected by a sensor is often provided for operation control.

  The mark is required to be a three-dimensional mark that does not have to be lost and can be detected by a sensor depending on the use situation and application of the sintered metal sprocket. The three-dimensional mark may be provided on the end face of the cam sprocket as disclosed in Patent Document 1 below, but when provided on the end face, it is difficult to visually confirm the mark, There is a problem that the installation position of the detection sensor is restricted. Therefore, a mark is provided on the cylindrical or conical side surface of the sprocket, for example, the outer peripheral surface of the flange or the outer peripheral surface of the boss portion. In this case, the mark is applied by sintering the sprocket compact and then processing it with a drill or the like.

  When applying a mark by processing with a drill or the like, there is a problem that the manufacturing cost of the sprocket becomes high because there is a process for applying the mark. In order to solve this problem, in Patent Document 2 below, the step for providing a mark is omitted by forming the mark with a mold.

JP 2003-148195 A JP 2008-298172 A

  In the mark given by the mold described in the above-mentioned document 2, the depth of the recess of the mark becomes shallow as the tooth tip diameter of the gear approaches the diameter of the cylinder or the cone, and it is difficult to visually confirm the mark. Or the mark formation itself may not be formed. Sintered metal sprockets are often sized for dimensional correction, but the marks provided by the mold can also be used as detents or positioning. When supplying a product to a sizing mold using a turntable, if the depth of the recess of the mark is small as described above, there is a possibility that the function of preventing rotation cannot be sufficiently exhibited. In that case, supply using a turntable cannot be performed, leading to an increase in manufacturing cost.

  The present invention secures the visibility of the mark provided on the side surface of the sintered metal sprocket even when the tooth tip diameter of the gear approaches the diameter of the cylinder or the cone. Furthermore, in order to enable manufacture on a turntable, it is an object to form a mark that can be prevented from rotating a mark provided on a side surface of a sintered metal sprocket.

  In order to solve the above problems, in the present invention, in the sprocket made of sintered metal having a cylindrical or conical flange on the upper part, a gear part on the lower part, and a mark on a side surface of the cylindrical or conical part, the mark Is configured such that at least one end is cut through the end face of the component in parallel with the axis of the component, and a convex portion corresponding to the gear portion is formed inside the mark.

  In the sintered metal sprocket according to the present invention, the mark provided on the side surface is formed by a groove that is parallel to the axis of the component and at least one end cut through the end surface of the component. In this case, the mark can be formed by a mold and applied, and the cutting process for applying the mark can be omitted to reduce the cost. Furthermore, since the convex part corresponding to the said gear part is formed in the inside of a mark, it becomes easy to recognize the position of a tooth tip visually, and the workability | operativity at the time of the assembly | attachment of a product improves.

  It is preferable that the mark has a mark bottom surface having an inner diameter that is larger than the tooth tip diameter of the gear portion, and the convex portion is formed on the mark bottom surface.

  The mark has a mark bottom surface that is inside diameter than the tooth tip diameter of the gear portion, and since the convex portion is formed on the mark bottom surface, positioning can be performed reliably even when using a turntable bush during sizing, Sizing workability is improved.

  The convex portion is preferably similar to the shape of the gear portion and larger than one tooth shape.

  Since the convex portion is similar to the shape of the gear portion and has a shape larger than one tooth profile, molding with a molding die is facilitated.

  It is preferable that there is a step between the end face of the convex part and the end face of the collar part.

  Since the structure has a step between the end faces of the convex portions, the position of the convex portions becomes clear and the visibility is improved when the position of the mark is visually confirmed. In particular, in the case of a product that processes the collar end face, the brightness of the two end face surfaces differs depending on the difference in surface roughness between the convex end face and the collar end face, and the visibility is further improved.

  In the sintered metal sprocket according to the present invention, the mark provided on the side surface is formed by a groove that is parallel to the axis of the component and at least one end cut through the end surface of the component. In this case, the mark can be formed by a mold and applied, and the cutting process for applying the mark can be omitted to reduce the cost. Furthermore, since the convex part corresponding to the said gear part is formed in the inside of a mark, it becomes easy to recognize the position of a tooth tip visually, and the workability | operativity at the time of the assembly | attachment of a product improves.

The front view which shows embodiment of the sintered metal sprocket of this invention Sectional view of the sintered metal sprocket of FIG. The figure which expanded the A section of FIG. The figure which expanded the B section of FIG. Sectional drawing which shows the powder molding process of the sintered metal sprocket of FIG. Cross section of the green compact obtained in the process of FIG.

Embodiments of the present invention will be described below with reference to FIGS. The illustrated sintered part 1 is a cam sprocket employed in an engine drive system, and product dimensions are as follows.
Buttock diameter: φ90mm
Gear part major axis: φ89.5mm
Product total length: 25mm

  The cam sprocket 1 has a tooth portion 3 for hanging a power transmission chain on the outer periphery of one end side of the main body portion 2. In addition, a flange 4 having a diameter larger than the standard outer diameter of the tooth 3 is provided on the outer periphery of the other end of the main body 2.

  One mark 5 is formed on the collar portion. The mark 5 is a groove that has at least one end cut through the flange end face 8 on the side formed on the upper punch of the component and is parallel to the axis of the component. This mark 5 is formed by a mold. And this mark is provided in the position which overlaps with one tooth | gear of a gearwheel, and this mark has the mark bottom face 11 which exists in the center side of a product rather than the gear tooth tip. Therefore, even when the tooth tip diameter of the gear is close to the diameter of the collar portion, the depth of the mark dent can be secured, and as a result, the visibility is improved and the function as a detent can be secured. it can.

  The mark has a convex portion 12 similar to the tooth tip shape and larger than the tooth shape on the mark bottom surface 11. Therefore, even when the tooth tip shape is small and difficult to check, the tooth tip position can be confirmed by the convex portion.

  Assuming that the straight line connecting the top of the sprocket gear tip and the product center is the tooth tip central shaft 13, the convex portion is formed at a position where the central shaft overlaps the gear tip central shaft 13. Therefore, the tooth tip position of the gear can be easily specified by confirming the position of the convex portion.

  This mark has, as two side surfaces 15, part of an arc having a center 14 on the tooth tip central axis 13 and on the outer periphery of the collar portion or on the outer side of the outer periphery. In the heel end surface view, a step is formed on the arc connecting the two side surfaces 15, the heel end surface on the center side of the arc is lowered, and the surface is defined as the convex end surface 16.

  This mark also serves as a timing mark for rotation control and a positioning mark for sizing. As a timing mark, it is necessary to be able to recognize the position of the tooth tip in the end face view. In this embodiment, since the convex portion 12 that is similar to the tooth tip shape and has the center axis on the tooth tip central axis 13 is formed inside the mark, the position of the tooth tip can be easily recognized in the end face view. can do.

  Since the positioning mark for sizing needs to function as a catch at the time of positioning, the depth of the mark is required. Since the mark bottom surface 11 is formed closer to the axis of the part than the tooth tip, the mark has a sufficient mark depth and can sufficiently function as a positioning mark.

  In the present embodiment, a step is provided on the convex end face 16 and the flange end face 8 on the arc connecting the side faces 15 of the mark. By providing a step, it becomes clear that the side surface is formed by one arc, and the visibility of the mark position is improved. Moreover, since the convex part end surface 16 has a level | step difference from the collar end surface 8, the raw material surface of a sintered product is maintained. When the heel end face is processed by cutting or the like, the visibility of the mark position is further improved due to the difference in brightness between the heel end face 8 and the convex end face 16. This step makes it clear that there is one mark. This has the effect of preventing the following problems. When two identical marks are formed across the tooth tip, there is a possibility that the positioning may not be fixed to either one because there are two marks in the positioning by sizing. The timing mark generally has one mark. Since there are two marks, there is a possibility that the position of the timing mark is wrong.

  As shown in FIG. 5, powder molding of the exemplary sintered metal sprocket 1 includes a contour molding portion 17 a of the tooth portion 3, a contour (outer periphery) molding portion 17 b of the collar portion 4, and a mark molding portion (molding for the mark 5. (Only the portion 17c is shown) is provided on the die 17, and is a combination of the die 17, the divided lower punch 18 composed of the lower 1 punch 18-1 and the lower 2 punch 18-2, the upper punch 19, and the core rod 20. Made using a mold. A green compact 21 obtained by molding is shown in FIG. The green compact 21 is sintered, and thereafter, the region defined by the chain line on the outer periphery of the main body 2 is cut to generate the tooth 3 and the flange 4. If necessary, the inner diameter surface 2a of the main body 2 and the assembly hole 2b are also cut.

  Through the above steps, a sintered metal sprocket having the marks 5 each formed by a vertically long groove is completed. In the sintered sprocket made of sintered metal, the cutting process of the mark 5 after sintering is omitted, the productivity and cost are reduced, and the assembling workability is improved by the convex portion.

DESCRIPTION OF SYMBOLS 1 Sintered metal sprocket 2 Main-body part 2a Inner diameter surface 2b Assembly hole 3 Tooth part 4 Gutter part 5 Mark 6 Side surface 8 End surface 10 Tooth tip 11 Mark bottom surface 12 Convex part 13 Tooth center axis 14 Arc center 15 Side 16 Convex part end 17 Die 17a Tooth contour forming portion 17b Tooth contour forming portion 17c Mark forming portion 18 Split lower punch 19 Upper punch 20 Core rod 21 Green compact

Claims (4)

A sintered metal sprocket having a cylindrical or conical flange on the upper part, a gear part on the lower part, and a mark (5) on the side surface (6) of the cylindrical or conical part,
The mark (5) is made of a sintered metal having a convex portion (12) corresponding to the gear portion inside the mark, at least one end being cut through the end face (8) of the component in parallel with the axis of the component. sprocket.   The said mark (5) has the mark bottom face (11) which exists in an internal diameter rather than the tooth-tip diameter of the said gear part, and the said convex part (12) is formed in the said mark bottom face (11). Sintered metal sprocket.   The sintered metal sprocket according to claim 1 or 2, wherein the convex portion (12) is similar in shape to the gear portion and has a shape larger than one tooth shape.   The sintered metal sprocket according to claim 2, wherein there is a step between the end surface of the convex portion (12) and the flange end surface (8).

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