Double-end bolt mounting tool for high-pressure oil pump of diesel engine

Abstract

The utility model discloses a double-end bolt installation tool of a diesel engine high-pressure oil pump, which comprises a step nut and a puller screw, the step nut is a combined body with a hexahedron at the upper end and a cylinder at the lower end, the center of the hexahedron is provided with an upper threaded hole matched with threads of the puller screw, and the center of the cylinder is provided with a lower threaded hole matched with external threads of a double-end bolt. And the upper threaded hole and the lower threaded hole are vertically communicated through the tool withdrawal groove. During use, the upper ends of the double-end bolts are screwed into the lower threaded holes of the stepped nuts, the lower ends of the double-end bolts are respectively screwed into the rack, the puller screws are screwed into the upper threaded holes of the stepped nuts, and the bottom surfaces of the puller screws are pressed on the top surfaces of the double-end bolts. By using the tool, the stud can be quickly and efficiently mounted and dismounted, the stud cannot be damaged, and the working safety of a high-pressure oil pump is ensured.

Description

Technical Field

[0001] This utility model belongs to the field of fitter operation technology, specifically relating to a tooling for fixing double-ended bolts used to install a high-pressure oil pump to a machine frame. Background Technology

[0002] Double-ended studs have two threaded sections, one at the top and one at the bottom, with a smooth shank in the middle. They are commonly used to connect thick plates and in situations where hexagonal bolts are inconvenient to use. The lower threaded section of the stud is screwed into the machine body, while the smooth shank and the upper threaded section protrude from the base plate of the component being connected. The component is effectively fixed to the machine body by tightening the nut on the upper threaded section. Compared to bolts and nuts, which have only one threaded connection, studs have two threaded connections, increasing the length of the load-bearing thread and thus improving the connection strength and reducing the shear stress of the thread.

[0003] The high-pressure fuel pump of a diesel engine is used to deliver fuel and is a crucial component. The pump base plate is secured to the engine frame by several double-ended bolts, which are then tightened with nuts to improve the pump's safety and stability during engine operation. Currently, pipe wrenches are commonly used to screw the lower threaded section of the double-ended bolts into the engine block. However, the large head of the pipe wrench makes operation difficult, and it can also damage the polished shank in the middle of the bolt. Since the double-ended bolt is under tension at both ends during use, the damaged shank is prone to stress concentration and failure. Utility Model Content

[0004] The purpose of this invention is to provide a simple and easy-to-use double-ended bolt mounting fixture for a diesel engine high-pressure oil pump.

[0005] This utility model is achieved through the following technical solution:

[0006] A double-ended bolt mounting fixture for a high-pressure oil pump of a diesel engine includes a stepped nut and a tightening screw. The stepped nut is a combination of a hexagonal upper end and a cylindrical lower end. The outer diameter D1 of the cylindrical end is larger than the outer diameter D2 of the hexagonal outer circle. The hexagonal end has an upper threaded hole at its center that matches the thread of the tightening screw, and the cylindrical end has a lower threaded hole at its center that matches the external thread of the double-ended bolt. The upper and lower threaded holes are connected vertically by a relief groove. The diameter d1 of the upper threaded hole is smaller than the diameter d2 of the lower threaded hole. In use, the upper end of the double-ended bolt is screwed into the lower threaded hole of the stepped nut, the lower ends of the double-ended bolt are screwed into the frame, and the tightening screw is screwed into the upper threaded hole of the stepped nut. The bottom surface of the tightening screw presses against the top surface of the double-ended bolt.

[0007] The objective of this utility model can also be further achieved through the following technical measures.

[0008] Furthermore, the upper threaded hole is a left-hand thread, and the tightening screw is also a left-hand screw.

[0009] Furthermore, the ratio of the hexagonal height H1 to the diameter d1 of the upper threaded hole is: H1 / d1 = 1.20~1.30. The ratio of the cylinder height H2 to the diameter d2 of the lower threaded hole is: H2 / d2 = 1.03~1.05.

[0010] Furthermore, the stepped nut is made of 45# steel, the tempering hardness of the 45# steel is HB260~280, and the hexagonal local quenching hardness of the stepped nut is HRC40~45.

[0011] Tighten the lower part of the stepped nut onto the upper end of the double-ended bolt, and then tighten the left-hand threaded locking screw. This secures the stepped nut, locking screw, and double-ended bolt together. A torque wrench can then be used to turn the upper hexagon of the stepped nut clockwise, thus screwing the lower end of the double-ended bolt into the frame and achieving the required torque. To remove the double-ended bolt, first tighten the lower part of the stepped nut onto the upper end of the double-ended bolt, then tighten the locking screw. At this point, the stepped nut, locking screw, and double-ended bolt are securely connected. When the wrench is turned counterclockwise on the upper hexagon of the stepped nut, the locking screw's thread direction is opposite to the lower thread direction of the stepped nut, ensuring the locking screw remains pressed against the top surface of the double-ended bolt. This prevents relative rotation between the stepped nut and the double-ended bolt. This invention allows for quick and efficient installation and removal of double-ended bolts without damage, ensuring the safe operation of the high-pressure oil pump.

[0012] The advantages and features of this utility model will be illustrated and explained through the following non-limiting description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description

[0013] Figure 1 This is a diagram showing the usage state of this utility model;

[0014] Figure 2 yes Figure 1 AA enlarged sectional view. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and an embodiment of the present invention used for mounting double-ended bolts on the high-pressure oil pump of L21 / 31 type diesel engine.

[0016] like Figure 1 and Figure 2As shown, this embodiment includes a stepped nut 1 and a tightening screw 2. The upper end of the stepped nut 1 is a hexagonal prism 11 for easy wrench gripping, and the lower end is a cylinder 12. The outer diameter D1 of the cylinder is larger than the outer diameter D2 of the hexagonal prism's circumscribed circle. The center of the hexagonal prism 11 has an upper threaded hole 111 that matches the left-hand thread of the tightening screw 2. The center of the cylinder 12 has a lower threaded hole 121 that matches the external thread of the stud bolt 10. The upper threaded hole 111 and the lower threaded hole 121 are connected vertically by a relief groove 112. The diameter d1 of the upper threaded hole is smaller than the diameter d2 of the lower threaded hole. In use, the upper end of the stud bolt 10 is screwed into the lower threaded hole 121 of the stepped nut, and the lower end of the stud bolt 10 is screwed into the frame 20. The tightening screw 2 is screwed into the upper threaded hole 111 of the stepped nut 1, and the bottom surface of the tightening screw 2 is pressed against the top surface of the stud bolt 10.

[0017] The upper threaded hole 111 is a left-hand thread, and the tightening screw 2 is also a left-hand screw. This structure facilitates the removal of the double-ended bolt 10. Use a wrench to turn the tightening screw 2 counterclockwise so that it is screwed into the upper threaded hole 111 of the stepped nut 1 until the bottom surface of the tightening screw 2 presses against the top surface of the double-ended bolt 10. At this time, the stepped nut 1, the tightening screw 2 and the double-ended bolt 10 are fixed together. When the wrench is turned counterclockwise on the stepped nut 1, since the left-hand thread of the tightening screw 2 and the right-hand thread of the lower thread 121 of the stepped nut 1 have opposite directions of rotation, the tightening screw 2 is always pressed against the top surface of the double-ended bolt 10. The stepped nut 1 and the double-ended bolt 10 will not rotate relative to each other. Turning the stepped nut 1 counterclockwise will drive the double-ended bolt 10 to rotate counterclockwise, thereby quickly and efficiently removing the double-ended bolt 10.

[0018] In this embodiment, the ratio of the height H1 of the hexagon to the diameter d1 of the upper threaded hole is H1 / d1 = 1.25, and the ratio of the height H2 of the cylinder to the diameter d2 of the lower threaded hole is H2 / d2 = 1.04. This ensures that the upper and lower ends of the tightening screw 2, the double-ended bolt 10, and the stepped nut 1 have sufficient threaded connection length, so that the stepped nut 1, the tightening screw 2, and the double-ended bolt 10 can be fixed together as one unit, making it easier to install or remove the double-ended bolt 10.

[0019] The stepped nut 1 is made of 45# steel, and the tempering hardness of the 45# steel is HB260~280. The hexagonal 11 of the stepped nut 1 is locally quenched to a hardness of HRC40~45, so as to improve the durability of this utility model.

[0020] The following describes the usage process of this utility model using the installation process of the five double-ended bolts 10 of the high-pressure oil pump of the L21 / 31 diesel engine as an example:

[0021] First, manually screw in the five M12 double-ended bolts 10 required for the installation of the high-pressure oil pump onto the frame 20 of the L21 / 31 diesel engine until they are manually tightened.

[0022] Then manually tighten the lower end of the stepped nut 1 onto an M12×75 double-ended bolt 10, and then turn the 40mm long M10 left-handed tightening screw 2 counterclockwise into the upper threaded hole 111 of the hexagon 11 until the bottom of the tightening screw 2 is pressed against the top surface of the double-ended bolt 10.

[0023] According to the design assembly requirements, set the torque wrench to 85 N·m. Then, place the torque wrench sleeve onto the hexagonal 11 at the upper end of the stepped nut 1, and turn the torque wrench clockwise until it clicks twice consecutively, indicating that the M12×75 double-ended bolt 10 has been tightened to the required torque of 85 N·m. Repeat the above process to screw the remaining four double-ended bolts 10 into the frame 10.

[0024] In addition to the above embodiments, the present invention may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A double-ended bolt mounting fixture for a diesel engine high-pressure oil pump, characterized in that, It includes a stepped nut and a tightening screw. The stepped nut is a combination of a hexagonal upper part and a cylindrical lower part. The outer diameter D1 of the cylindrical part is larger than the outer diameter D2 of the hexagonal outer circle. The center of the hexagonal part has an upper threaded hole that matches the thread of the tightening screw, and the center of the cylindrical part has a lower threaded hole that matches the external thread of the double-ended bolt. The upper and lower threaded holes are connected by a relief groove. The diameter d1 of the upper threaded hole is smaller than the diameter d2 of the lower threaded hole. In use, the upper end of the double-ended bolt is screwed into the lower threaded hole of the stepped nut, and the lower ends of the double-ended bolts are screwed into the frame. The tightening screw is screwed into the upper threaded hole of the stepped nut, and the bottom surface of the tightening screw is pressed against the top surface of the double-ended bolt.

2. The double-ended bolt mounting fixture for the high-pressure oil pump of a diesel engine as described in claim 1, characterized in that, The upper threaded hole is a left-hand thread, and the tightening screw is also a left-hand screw.

3. The double-ended bolt mounting fixture for the high-pressure oil pump of a diesel engine as described in claim 1, characterized in that, The ratio of the height H1 of the hexagon to the diameter d1 of the threaded hole is: H1 / d1 = 1.20 to 1.

30.

4. The double-ended bolt mounting fixture for the high-pressure oil pump of a diesel engine as described in claim 1, characterized in that, The ratio of the cylinder height H2 to the diameter of the threaded hole d2: H2 / d2 = 1.03~1.

05.

5. The double-ended bolt mounting fixture for a diesel engine high-pressure oil pump as described in claim 1, characterized in that, The stepped nut is made of 45# steel, and the tempering hardness of the 45# steel is HB260~280. The hexagonal local quenching hardness of the stepped nut is HRC40~45.

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