Special clamp for machining piston of diesel engine

Abstract

The invention discloses a special fixture for processing a diesel engine piston. The fixture is positioned by tensioning an inner cavity of the piston, can fully ensure that the wall thickness of a skirt part is uniform, locks a workpiece by adopting a mode of tensioning a pin hole by a pull pin, can fully ensure that the piston is firmly clamped, and can complete processing of a plurality of procedures by one-time clamping. Machining procedures are integrated, and equipment investment is reduced, so that cost is reduced, clamping times are reduced, and production efficiency is improved. The clamping labor intensity of an operator is greatly reduced, the automatic clamping time is shortened, the fault rate is decreased, and the device is more suitable for automatic machining. The method has high development value and wide market prospect, and can generate good social benefits and economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of diesel engine piston processing, in particular to a special fixture for diesel engine piston processing. Background Art

[0002] The structure of the piston is special and the processing procedures are relatively complicated. The current more mature processing solutions are: 1. Install a mold core that is consistent with the inner cavity of the blank on the lathe spindle to locate the inner cavity of the workpiece, use the tailstock to press the piston against the tooling, and then process the outer circle of the piston head and part of the top surface (during the processing, the tailstock is always pressing against the top surface, and the pressed part cannot be processed). 2. Replace with another lathe, use a three-jaw chuck to clamp the processed head as a reference, and turn the outer circle and end face of the group. 3. Replace the third lathe with a positioning tool dedicated to the workpiece, install the processed group end face on the positioning tooling, tighten it to the positioning tooling with a pin hole, and process the remaining top surface of the piston and the combustion chamber.

[0003] The current solution to this complex process involves designing a specialized fixture that uses the piston's inner cavity to tighten and position the workpiece, ensuring uniform skirt wall thickness. Externally mounted jaws tighten the pinholes to secure the workpiece, ensuring a secure clamp and enabling multiple machining steps to be completed in a single setup. However, this fixture is limited to pistons with a significant difference between the minor axis and the outer diameter of the skirt. Pistons clamped with other fixtures cannot be machined because the jaws at the pinhole protrude above the outer diameter of the skirt after the piston is clamped.

[0004] It can be seen that the problems with the existing processing scheme are: high cost, requiring three pieces of equipment and supporting tooling; low efficiency, multiple clamping in the three processes, and long debugging time.

[0005] To this end, the present application designs a special fixture for diesel engine piston processing to solve the above problems. Summary of the Invention

[0006] In order to make up for the deficiencies in the prior art, the present invention provides a special fixture for machining diesel engine pistons.

[0007] A special fixture for machining diesel engine pistons, comprising a main spindle, characterized in that: A rotating oil cylinder is provided at the tail end of the main shaft, and a clamp body is fixedly connected to the front end of the main shaft. The clamp body is fixedly connected to the main shaft through a connecting disk. A pull rod passes through the center of the connecting disk. The pull rod passes through the main shaft and connects to the rotating oil cylinder. A seat body is fixedly connected to the connecting disk, and a positioning assembly is installed on the seat body. The positioning assembly is used to fix the piston.

[0008] Furthermore, in order to better realize the present invention, the positioning assembly includes a skirt limit block and a pin hole limit block, both of which are distributed in a cross shape and can be installed on the base body to slide up and down, for lifting the piston and limiting left and right displacement.

[0009] Furthermore, in order to better implement the present invention, the bottom of the skirt limit block is connected to the connecting plate through a spring, and the bottom of the pin hole limit block is connected to the seat body through a spring.

[0010] Furthermore, in order to better realize the present invention, the positioning assembly includes a pull ring, the bottom of the pull ring is threadedly connected to the pull rod, the pull ring is slidably arranged in the base body, and a pull pin is detachably inserted in the pull ring.

[0011] Furthermore, in order to better implement the present invention, the positioning assembly includes a top limit block, and the top limit block is locked on the top of the base body by bolts.

[0012] Furthermore, in order to better implement the present invention, the pull pin is placed independently before clamping and passes through the piston pin hole and the pull ring during processing.

[0013] Furthermore, in order to better implement the present invention, the rotating oil cylinder drives the pull rod to pull down the pull ring and the pull pin, so that the top of the piston cavity contacts the top limit block to complete the fixing of the piston.

[0014] The beneficial effects of the present invention are: The present invention integrates processing steps, reduces equipment investment, and thus reduces costs. It also reduces the number of clamping times and improves production efficiency. On a single piece of equipment, rough machining of the piston's outer diameter, top, and combustion chamber can be completed through a single positioning and clamping process, reducing equipment investment and tooling investment. While ensuring processing quality, the three processes are combined into one, improving processing efficiency. When replacing a new product, the time required to replace and debug the tooling of three pieces of equipment can now be reduced to replacing the tooling of only one piece of equipment, thus reducing debugging time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the present invention installed on the main shaft of the equipment; Figure 2 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 3 For the present invention Figure 2 Schematic diagram of the structure after removing the skirt limit block.

[0016] In the figure, 1. Rotating cylinder, 2. Spindle, 3. Clamp body, 4. Piston, 5. Pull rod, 6. Connecting plate, 7. Chip guard, 8. Skirt limit block, 9. Pin hole limit block, 10. Top limit block, 11. Pull pin, 12. Pull ring, 13. Seat, 14. Spring. DETAILED DESCRIPTION

[0017] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in a variety of different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely intended to represent selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0019] Figure 1-Figure 3 This is a specific embodiment of the present invention, a specialized fixture for diesel engine piston machining. The fixture body 3 is assembled onto the equipment's main shaft 2 via a connecting plate 6. A rotary cylinder 1 is mounted at the end of the main shaft 2. This rotary cylinder 1 is connected to the fixture body 3 via a tie rod 5. The interior of the main shaft 2 is hollow to allow the tie rod 5 to pass through. The diesel engine piston 4 is mounted on the fixture body 3.

[0020] The seat 14 is bolted to the connecting plate 6. The skirt stopper 8 is mounted on the seat 14, ensuring that it can move up and down along the seat 14. The pin hole stopper 9 is mounted on the seat 14, arranged in a cross position with the skirt stopper 8, ensuring that it can move up and down along the seat 14. The pull ring 13 is installed inside the seat 14 and is threadedly connected to the pull rod 5. The pull ring 13 can move up and down inside the seat 14. The pull pin 11 passes through the pull ring 13. Before the piston 4 is processed, the pull pin 11 will not be installed in the fixture and needs to be placed separately. The top stopper 10 is locked to the top of the seat 14 with bolts.

[0021] The specific usage of this embodiment is as follows: Place the piston 4 on the fixture, pass the pull pin 11 through the piston pin hole and the pull ring 13, then rotate the oil cylinder 1 to start, and drive the pull ring 13 to move downward through the pull rod 5, thereby driving the pull pin 11 to move downward. Because the top of the inner cavity of the piston 4 is in contact with the top limit block 10 at this time, the piston 4 will not be displaced, and the pull pin 11 will pull the piston 4 toward the connecting disk 6, so that it is tightly fixed on the fixture. The clamping force is stable, the clamping does not deform, and the main shaft rotates to process the piston.

[0022] In this case, after processing, the piston top thickness is tested to be qualified, but the wall thickness is uneven, and the difference in wall thickness on both sides exceeds the tolerance, which does not meet the precision requirements.

[0023] Therefore, based on the above, skirt limit blocks 8 and pin hole limit blocks 9 are added. When processing the piston workpiece, the piston 4 is placed on the fixture, and the skirt limit blocks 8 and pin hole limit blocks 9 will lift the piston 4 so that the piston 4 will not contact the top limit block 10. The skirt limit blocks 8 and pin hole limit blocks 9 will limit the front, back, left and right positions of the piston 4 to ensure that the dimensions of the processed piston group meet the requirements of the product drawings. Pass the pull pin 11 through the piston pin hole and the pull ring 13, and then rotate the oil cylinder 1 to start, and drive the pull ring 13 to move downward through the pull rod 5, and then drive the pull pin 11 to move downward. The pull pin 11 will pull the piston 4 toward the connecting disk 6, and will stop when the top of the inner cavity of the piston 4 contacts the top limit block 10. At this time, the up and down, front and back, left and right directions of the piston 4 are all fixed, the clamping force is stable, the clamping is not deformed, and the main shaft rotates to process the piston.

[0024] After processing, the piston top thickness is qualified, the wall thickness is uniform, the wall thickness difference is stable, and it meets the precision requirements.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limiting. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A special fixture for machining diesel engine pistons, comprising a spindle (2), characterized in that: A rotating oil cylinder (1) is provided at the tail end of the main shaft (2), and a clamp body (3) is fixedly connected to the front end of the main shaft (2). The clamp body (3) is fixedly connected to the main shaft (2) through a connecting plate (6). A pull rod (5) passes through the center of the connecting plate (6). The pull rod (5) passes through the main shaft (2) and is connected to the rotating oil cylinder (1). A seat body (13) is fixedly connected to the connecting plate (6). A positioning assembly is installed on the seat body (13), and the positioning assembly is used to fix the piston (4).

2. The special fixture for diesel engine piston machining according to claim 1, characterized in that: The positioning assembly comprises a skirt limit block (8) and a pin hole limit block (9), both of which are arranged in a cross shape and are mounted on the seat body (13) so as to be slidable up and down, and are used to lift the piston (4) and limit left and right displacement.

3. The special fixture for diesel engine piston machining according to claim 2, characterized in that: The bottom of the skirt limit block (8) is connected to the connecting plate (6) via a spring (14), and the bottom of the pin hole limit block (9) is connected to the seat body (13) via a spring (14).

4. The special fixture for machining diesel engine pistons according to claim 1, characterized in that: The positioning assembly includes a pull ring (13), the bottom of the pull ring (13) is threadedly connected to the pull rod (5), the pull ring is slidably arranged in the base (14), and a pull pin (11) is detachably inserted into the pull ring (13).

5. The special fixture for diesel engine piston machining according to claim 1, characterized in that: The positioning assembly comprises a top limit block (10), which is locked on the top of the seat body (14) by means of bolts.

6. The special fixture for machining diesel engine pistons according to claim 4, characterized in that: The pull pin (11) is placed independently before clamping and passes through the piston pin hole and the pull ring (13) during processing.

7. The special fixture for machining diesel engine pistons according to claim 1, characterized in that: The rotating oil cylinder (1) drives the pull rod (5) to pull down the pull ring (13) and the pull pin (11), so that the top of the piston cavity contacts the top limit block (10) to complete the fixing of the piston (4).

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