Internal positioning tooling for forged steel pistons and its positioning method

Abstract

The present application discloses an internal positioning tooling for a forged steel piston and its positioning method, which includes a positioning seat, a support seat arranged at one end of the positioning seat, and a top support seat detachably connected to the other end of the positioning seat. The positioning seat is used for internal positioning of the blank. A convex portion is provided on the outer peripheral surface of the positioning seat, and the convex portion is used for clamping with the inner concave cavity of the blank. The top support seat and the support seat are respectively used for limiting both ends of the blank. The present application has the effect of improving the coaxiality between the outer circle of the piston skirt and the inner cavity.

Description

Technical Field

[0001] This application relates to the field of piston processing, and particularly to an internal positioning tooling for forged steel pistons and its positioning method. Background Art

[0002] A forged steel piston is an engine piston processed by forging. Forged steel pistons can be divided into integral pistons and split pistons. The split piston is composed of a piston head and a piston skirt welded together. The piston skirt refers to the part below the last ring groove of the piston. The pin boss hole is located in the piston skirt. The piston skirt contacts the cylinder wall to guide the piston to reciprocate in the cylinder and bears the lateral thrust from the cylinder wall.

[0003] In the rough machining stage of the piston skirt, a three-jaw self-centering chuck or other fixtures are usually used to fix the blank on the machine tool. Through preliminary turning, milling and other processes, most of the surplus is removed to form the preliminary shape of the piston. However, in the actual machining process, when clamping the outer periphery of the blank with three jaws or other fixtures, various factors will affect the machining accuracy of the piston skirt. For example, the jaws will gradually wear during use, especially the part with greater force at the front end wears more seriously. This wear will cause the jaws to form a "bell mouth" state, resulting in uneven force on the workpiece during clamping, thus affecting the uniformity of the wall thickness of the piston skirt. In addition, too large a clamping force of the jaws will cause the workpiece to deform and affect the machining accuracy; too small a clamping force may cause the workpiece to loosen or shift during machining, thus there is a risk that the machining accuracy is affected, making the coaxiality between the outer circle and the inner cavity of the piston skirt not high. Therefore, there is still room for improvement. Summary of the Invention

[0004] In order to improve the coaxiality effect between the outer circle and the inner cavity of the piston skirt, this application provides an internal positioning tooling for forged steel pistons and its positioning method.

[0005] An internal positioning tooling for forged steel pistons provided by this application adopts the following technical solution:

[0006] An internal positioning tooling for forged steel pistons includes a positioning seat, a support seat arranged at one end of the positioning seat, and a top support seat detachably connected to the other end of the positioning seat. The positioning seat is used for internal positioning of the blank. A convex part is arranged on the outer peripheral surface of the positioning seat, and the convex part is used for clamping with the inner concave cavity of the blank. The top support seat and the support seat are respectively used for limiting the two ends of the blank.

[0007] By adopting the above technical scheme, the raised portion of the positioning seat is made according to the shape of the inner concave cavity of the blank. When the blank is installed on the positioning seat, the raised portion of the positioning seat is clamped with the inner concave cavity of the blank, thereby realizing internal positioning and internal support of the blank. The positioning seat body and the raised portion play a role in stabilizing the blank. In addition, the top support seat cooperates with the support seat to support the axial position of the blank, which is beneficial to further improve the overall stability of the blank and avoids the risk of reduced accuracy caused by wear of the claws or too loose or too tight clamping force. It is beneficial to improve the processing accuracy of the piston skirt, ensure the wall thickness difference of the piston skirt, keep the processed wall thickness difference of the piston skirt within 0.4mm, improve the coaxiality of the outer circle of the piston skirt and the inner cavity, which is beneficial to improve the piston yield.

[0008] Preferably, the protrusion is detachably connected to the positioning seat.

[0009] By adopting the above technical solution, the protrusion and the positioning seat can be separated. When piston processing procedures of different specifications are required, the protrusion can be replaced according to the shape of the inner concave cavity of the piston blank, which is beneficial to improving the applicability of the internal positioning tooling.

[0010] Preferably, a threaded locking piece is provided between the protruding portion and the positioning seat, the protruding portion is provided with a countersunk hole for accommodating the threaded locking piece, and the surface of the clamping block is provided with a threaded hole for threaded connection with the threaded locking piece.

[0011] By adopting the above technical solution, the countersunk hole accommodates the threaded locking piece to reduce the situation where the threaded locking piece protrudes from the surface of the raised portion, thereby reducing the clamping effect between the raised portion and the blank. The positioning seat opens a threaded hole to cooperate with the bolt locking piece to lock the raised portion, which is beneficial to improve the stability of the raised portion.

[0012] Preferably, a snap-fitting position is provided on one side of the protruding portion facing the positioning seat, and the positioning seat is provided with a snap-fitting block, so that the protruding portion and the positioning seat are assembled by snapping the snap-fitting position and the snap-fitting block.

[0013] By adopting the above technical solution, the protrusion and the positioning seat are assembled by means of the clamping position and the clamping block, which is beneficial to improving the installation accuracy of the protrusion at the positioning seat, and at the same time facilitates the alignment of the countersunk hole of the protrusion and the threaded hole of the positioning seat, and facilitates the threaded locking member to lock the protrusion and the positioning seat.

[0014] Preferably, a positioning shaft is provided at one end of the positioning seat away from the supporting seat, and a positioning hole is formed through the top supporting seat, and the positioning hole is used for the positioning shaft to pass through.

[0015] By adopting the above technical solution, the positioning seat and the top support seat are plugged together through the positioning shaft and the positioning hole, which is beneficial to maintaining the assembly accuracy of the positioning seat and the top support seat in the axial position.

[0016] Preferably, the clamping block is protrudingly arranged at one end away from the supporting seat, a clamping groove is formed at the protruding end of the clamping block, and one end of the top supporting seat facing the positioning seat is clamped with the clamping groove.

[0017] By adopting the above technical solution, the clamping block as a whole protrudes from the positioning seat and is provided with a clamping groove. When the top support seat and the positioning seat are assembled, one end of the top support seat facing the positioning seat is clamped with the clamping groove of the clamping block, which is beneficial to maintaining the stability of the relative position between the positioning seat and the top support seat. The positioning seat and the top support seat together constitute an internal positioning tooling to support the inner side of the blank, which is beneficial to improving the processing stability of the blank.

[0018] Preferably, the internal positioning tooling also includes a locking disk, which is located on the side of the top support seat away from the positioning seat, and the locking disk is provided with a connecting hole along its own axial direction, and the inner wall of the connecting hole is provided with an internal thread, and the end of the positioning shaft away from the positioning seat is provided with an external thread, and the connecting hole is threadedly connected to the end of the positioning shaft away from the positioning seat.

[0019] By adopting the above technical solution, the locking disk is threadedly connected to the end of the positioning shaft away from the positioning seat through the connecting hole, thereby limiting the top support seat, which is beneficial to improving the stability of the top support seat.

[0020] A positioning method for a forged steel piston, using an internal positioning tool, comprises the following steps:

[0021] S1: The piston blank is sleeved on the positioning seat, and the convex portion of the positioning seat is engaged with the inner concave cavity of the blank to perform internal positioning and internal support on the inner side of the blank;

[0022] S2: One end of the blank is pressed against the support seat, and then the top support seat is assembled on the end of the positioning seat, so that the other end of the blank is pressed against the top support seat to limit the axial position of the blank.

[0023] By adopting the above technical solution, when the blank is installed on the positioning seat, the raised portion of the positioning seat is clamped with the inner concave cavity of the blank, thereby realizing internal positioning and internal support of the blank. The positioning seat body and the raised portion play a role in stabilizing the blank. The supporting seat cooperates with the support seat to support the axial position of the blank, which is beneficial to further improve the overall stability of the blank and improve the processing accuracy of the piston skirt.

[0024] In summary, the present application includes at least one of the following beneficial technical effects:

[0025] 1. Make the convex part of the positioning seat according to the shape of the inner concave cavity of the blank. The convex part of the positioning seat is clamped with the inner concave cavity of the blank, so as to realize inner positioning and inner support for the blank. The top support seat cooperates with the support seat to limit the axial position of the blank, which is beneficial to further improve the overall stability of the blank. At the same time, it avoids the risk of accuracy decline caused by the wear of the clamping jaws or the too loose or too tight clamping force, and is beneficial to improve the machining accuracy of the piston skirt;

[0026] 2. The convex part is detachably connected to the positioning seat, so as to replace the convex part according to the shape of the inner concave cavity of the piston blank, which is beneficial to improve the applicability of the inner positioning tooling;

[0027] 3. The clamping block protrudes from the positioning seat as a whole and is clamped in the clamping groove. When the top support seat and the positioning seat are assembled, the end of the top support seat facing the positioning seat is clamped and matched with the clamping groove of the clamping block, which is beneficial to maintaining the stability of the relative position between the positioning seat and the top support seat. The positioning seat and the top support seat together form an inner positioning tooling to support the inner side of the blank, which is beneficial to improve the machining stability of the blank. Brief Description of the Drawings

[0028] Figure 1 is an exploded view of an inner positioning tooling for a forged steel piston according to an embodiment of the present application.

[0029] Figure 2 is an assembly view of an inner positioning tooling for a forged steel piston and a blank according to an embodiment of the present application.

[0030] Figure 3 is an exploded view among the positioning seat, the convex part and the top support seat in an inner positioning tooling for a forged steel piston according to an embodiment of the present application.

[0031] Description of the Reference Numerals: 1, support seat; 2, positioning seat; 21, positioning shaft; 3, top support seat; 31, top support part; 32, connecting part; 33, positioning hole; 4, blank; 41, inner concave cavity; 42, pin seat hole; 5, lock disc; 51, connecting hole; 6, convex part; 61, clamping position; 62, counterbore; 7, clamping block; 71, threaded hole; 72, clamping groove; 8, threaded locking piece; 9, avoidance groove. Detailed Description of the Embodiment

[0032] The following will Figures 1-3 make a further detailed description of the present application in conjunction with the attached

[0033] The embodiment of the present application discloses an inner positioning tooling for a forged steel piston. Refer to Figure 1 and Figure 2, including a positioning seat 2, a support seat 1 fixed to one end of the positioning seat 2, a top support seat 3 detachably connected to the other end of the positioning seat 2, and a lock plate 5 for locking the top support seat 3. Among them, the positioning seat 2 is used for inner positioning of the blank part 4. A convex portion 6 is provided on the outer peripheral surface of the positioning seat 2, and the convex portion 6 is used for clamping with the inner concave cavity 41 of the blank part 4. The top support seat 3 and the support seat 1 are respectively used for limiting the two ends of the blank part 4.

[0034] In this embodiment, the inner concave cavities 41 of the forged steel piston blank part 4 are respectively located on the upper and lower sides of the blank part 4. In addition, the two pin seat holes 42 of the forged steel piston blank part 4 are respectively located on the left and right sides of the blank part 4.

[0035] The support seat 1 is a disc, and the axis of the support seat 1 coincides with the axis of the positioning seat 2. The left and right sides of the positioning seat 2 are vertical sections and are respectively provided with avoidance grooves 9, so that when machining the pin seat holes 42 of the blank part 4, the avoidance grooves 9 can provide enough operating space for the tool.

[0036] In order to facilitate the machining of piston skirts of different specifications, there are 2 convex portions 6 in total in the embodiment of the present application, and they are respectively detachably connected to the upper and lower sides of the positioning seat 2. Specifically, clamping blocks 7 are symmetrically fixed on the upper and lower sides of the positioning seat 2. The two convex portions 6 correspond to the two clamping blocks 7 one by one. A clamping position 61 is provided on the side of the convex portion 6 facing the positioning seat 2. The assembly purpose between the convex portion 6 and the positioning seat 2 is completed by the clamping of the clamping position 61 and the clamping block 7, and the convex portion 6 can be replaced according to the shape of the inner concave cavity 41 of the piston blank part 4, which is beneficial to improving the applicability of the inner positioning tooling.

[0037] Refer to Figure 1 and Figure 3 , in this embodiment, a threaded locking member 8 is installed between the convex portion 6 and the positioning seat 2. The threaded locking member 8 is specifically a bolt. A counterbore 62 for accommodating the threaded locking member 8 is axially penetrated through the convex portion 6 along the radial direction of the positioning seat 2. A threaded hole 71 for threadedly connecting with the threaded locking member 8 is axially penetrated through the clamping block 7 along the radial direction of the positioning seat 2. The positioning seat 2 and the convex portion 6 are locked by the bolt locking member, which is beneficial to improving the stability of the convex portion 6.

[0038] In this embodiment, a positioning shaft 21 is provided at one end of the positioning seat 2 away from the support seat 1. The axis of the positioning shaft 21 coincides with the axis of the positioning seat 2. A positioning hole 33 is axially penetrated through the top support seat 3 along its own axis, and the positioning shaft 21 passes through the positioning hole 33. The positioning seat 2 and the top support seat 3 are in plug-in fit through the positioning shaft 21 and the positioning hole 33, which is beneficial to maintaining the assembly accuracy of the positioning seat 2 and the top support seat 3 in the axial position.

[0039] In this embodiment, the top support seat 3 includes a connecting portion 32 and a top support portion 31, wherein the connecting portion 32 is block-shaped and has avoidance grooves 9 on both sides. The top support portion 31 is cylindrical, and the connecting portion 32 is centrally arranged at the end surface of the top support portion 31, and the outer diameter of the top support portion 31 is greater than the maximum outer diameter of the blank 4. In addition, the ends of the two clamping blocks 7 at the positioning seat 2 are protruded in the direction away from the support seat 1, and the protruding ends of the clamping blocks 7 are provided with a clamping groove 72. The clamping grooves 72 of the two clamping blocks 7 are arranged opposite to each other, and the clamping groove 72 is opened toward one end of the top support seat 3. The connecting portion 32 of the top support seat 3 is clamped with the two clamping grooves 72. When the top support seat 3 and the positioning seat 2 are assembled, the end of the top support seat 3 facing the positioning seat 2 is clamped with the clamping groove 72 of the clamping block 7, which is conducive to maintaining the stability of the relative position between the positioning seat 2 and the top support seat 3. The positioning seat 2 and the top support seat 3 together constitute an inner positioning tool to support the inner side of the blank 4, which is conducive to improving the processing stability of the blank 4. In addition, the extension direction of the clamping groove 72 is parallel to the length direction of the positioning shaft 21, so that the clamping groove 72 acts as a guide rail for the connecting portion 32, so that the connecting portion 32 can slide at the clamping groove 72, so as to adjust the distance between the support seat 1 and the top support seat 3 to adapt to blanks 4 of different lengths.

[0040] In this embodiment, the lock plate 5 is located on the side of the top support seat 3 away from the positioning seat 2. The lock plate 5 is provided with a connecting hole 51 along its own axial direction. The inner wall of the connecting hole 51 is provided with an internal thread. The end of the positioning shaft 21 away from the positioning seat 2 is provided with an external thread. The connecting hole 51 is threadedly connected to the end of the positioning shaft 21 away from the positioning seat 2. The lock plate 5 is threadedly connected to the end of the positioning shaft 21 away from the positioning seat 2 through the connecting hole 51, thereby limiting the top support seat 3, which is conducive to improving the stability of the top support seat 3.

[0041] A positioning method for a forged steel piston, using an internal positioning tool, comprises the following steps:

[0042] S1: Select the protrusion 6 according to the piston specifications, and engage the engaging position 61 of the protrusion 6 with the engaging block 7 of the positioning seat 2. The end of the protrusion 6 is against the end surface of the support seat 1, so that the countersunk hole 62 of the protrusion 6 is aligned with the threaded hole 71 of the engaging block 7, and then use bolts to lock the two protrusions 6 on the upper and lower sides of the positioning seat 2 respectively.

[0043] Then the piston blank 4 is sleeved on the positioning seat 2 towards the support seat 1, the positioning seat 2 is penetrated into the blank 4, and the raised portion 6 of the positioning seat 2 is engaged with the inner concave cavity 41 of the blank 4 to internally position and support the inner side of the blank 4.

[0044] S2: Push one end of the blank 4 against the support seat 1, then assemble the top support seat 3 to the end of the positioning seat 2 along the direction of the positioning axis 21, so that the other end of the blank 4 pushes against the top support seat 3 to limit the axial position of the blank 4.

[0045] Specifically, the positioning hole 33 of the top support seat 3 is plugged in, and the connecting part 32 of the positioning seat 2 enters from the slot 72 ports of the two clamping blocks 7 and completes the clamping step. At this time, the slots 72 of the two clamping blocks 7 are respectively clamped on the upper and lower sides of the connecting part 32 and act as a guide rail. The top support seat 3 moves along the axial direction of the positioning shaft 21 toward the support seat 1 until the top support part 31 abuts against the end of the blank 4, and then the connecting hole 51 of the locking disk 5 is threadedly connected to the end of the positioning shaft 21 away from the positioning seat 2, and is screwed in toward the support seat 1 until it is tightly against the top support seat 3, thereby limiting the top support seat 3 to improve the stability of the top support seat 3.

[0046] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An internal positioning tool for a forged steel piston, characterized in that: The invention comprises a positioning seat (2), a support seat (1) arranged at one end of the positioning seat (2), and a top support seat (3) detachably connected to the other end of the positioning seat (2); the positioning seat (2) is used for internal positioning of a blank (4); a protrusion (6) is arranged on the outer peripheral surface of the positioning seat (2); the protrusion (6) is used for clamping with an inner concave cavity (41) of the blank (4); the top support seat (3) and the support seat (1) are respectively used for limiting the two ends of the blank (4); The protruding portion (6) is detachably connected to the positioning seat (2); The protruding portion (6) is provided with a snap-fit ​​position (61) on one side facing the positioning seat (2), and the positioning seat (2) is provided with a snap-fit ​​block (7), so that the protruding portion (6) and the positioning seat (2) are assembled by snapping the snap-fit ​​position (61) and the snap-fit ​​block (7); The clamping block (7) is protrudingly arranged at one end away from the support seat (1), and a clamping groove (72) is provided at the protruding end of the clamping block (7), and one end of the top support seat (3) facing the positioning seat (2) is clamped with the clamping groove (72); A positioning shaft (21) is provided at one end of the positioning seat (2) away from the supporting seat (1), and a positioning hole (33) is formed through the top supporting seat (3), and the positioning hole (33) is used for the positioning shaft (21) to pass through; The inner positioning tool also includes a locking plate (5), the locking plate (5) is located on the side of the top support seat (3) away from the positioning seat (2), the locking plate (5) is provided with a connecting hole (51) along its own axial direction, the inner wall of the connecting hole (51) is provided with an internal thread, the end of the positioning shaft (21) away from the positioning seat (2) is provided with an external thread, and the connecting hole (51) is threadedly connected to the end of the positioning shaft (21) away from the positioning seat (2).

2. The inner positioning tool for a forged steel piston according to claim 1, characterized in that: A threaded locking member (8) is provided between the protruding portion (6) and the positioning seat (2); the protruding portion (6) is provided with a countersunk hole (62) for accommodating the threaded locking member (8); and the surface of the clamping block (7) is provided with a threaded hole (71) for threaded connection with the threaded locking member (8).

3. A positioning method for a forged steel piston, using the internal positioning tool for a forged steel piston according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1: The piston blank (4) is sleeved on the positioning seat (2), and the protrusion (6) of the positioning seat (2) is engaged with the inner concave cavity (41) of the blank (4) to perform internal positioning and internal support on the inner side of the blank (4); S2: one end of the blank (4) is pressed against the support seat (1), and then the top support seat (3) is assembled on the end of the positioning seat (2), so that the other end of the blank (4) is pressed against the top support seat (3) to limit the axial position of the blank (4).

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