Internal hexagonal bolt tightening tool for narrow and small space of engine
By designing a hex bolt tightening tool for the confined space of an engine, the problem of tightening and disassembling the hex bolts of the high-pressure fuel pump in confined spaces has been solved, enabling efficient manual tightening and disassembly and reducing after-sales service costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2026-03-03
AI Technical Summary
In engine maintenance, the internal hex bolts of the high-pressure fuel pump are located in a confined space, making it difficult to tighten and disassemble without large vehicle equipment, resulting in difficulties and high costs for after-sales service.
Design a tool that includes an adapter, an eccentric socket, an extension bar, and a ratchet wrench. The adapter engages with an internal hex bolt, and the eccentric socket and extension bar extend the operating point. The ratchet wrench's small-angle tightening function and the torque wrench enable efficient tightening and disassembly in confined spaces.
It enables the tightening and loosening of the internal hex bolts of the high-pressure fuel pump through manual operation without the need for large equipment, reducing the difficulty and cost of after-sales service. It is easy to operate and suitable for internal hex bolts in various confined spaces.
Smart Images
Figure CN223961255U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of engines and relates to an engine repair tool, and more particularly to an internal hex bolt tightening tool for use in the confined space of an engine. Background Technology
[0002] Among engine components, the high-pressure fuel pump is a core part, responsible for delivering fuel, establishing fuel pressure, and regulating fuel pressure in real time. The quality of the high-pressure fuel pump's installation directly affects engine performance. Due to the crucial role of the high-pressure fuel pump in the engine, many manufacturers can only choose their existing, mature products. One particular high-pressure fuel pump boasts excellent performance, but it requires the use of Allen bolts for fastening. One of these bolts is obstructed by components after the high-pressure fuel pump is installed in the engine, resulting in limited space around the bolt and making installation and removal difficult.
[0003] During engine assembly in the production workshop, the method for installing the high-pressure fuel pump is to first install it onto the gear housing. Since the cylinder block has not yet been installed, there are no obstructions on the left side of the high-pressure fuel pump, providing sufficient space to tighten the high-pressure fuel pump's fastening bolts first. Then, a large overhead crane is used to lift the high-pressure fuel pump and gear housing as a whole and install them onto the engine cylinder block. This method is feasible for assembly on the production line in the workshop, but large overhead cranes are not available in the aftermarket, making subsequent repair and disassembly quite difficult. Therefore, there is an urgent need to consider a tool for manually installing and removing hex bolts without relying on large lifting equipment. Utility Model Content
[0004] To address the issue in the aftermarket where the hex bolts inside the high-pressure fuel pump cannot be tightened or disassembled in confined spaces when the engine is not being lifted by large cranes, this solution aims to reduce the difficulty of after-sales service and save on after-sales service costs.
[0005] The purpose of this invention is to provide a tool for tightening hexagonal socket head cap bolts in the confined space of an engine. This tool allows for manual tightening of the high-pressure fuel pump hexagonal socket bolts in this confined space to the specified torque, without requiring heavy lifting equipment. It also offers advantages such as ease of use, versatility, simple structure, and portability.
[0006] To achieve the above objectives, the present invention provides a tool for tightening hexagonal socket head cap screws in confined spaces, including an adapter, an eccentric sleeve, an extension rod, and a ratchet wrench. One end of the adapter is a hexagonal head for connecting the hexagonal socket head cap screw, and the other end is a dodecagonal head. One end of the eccentric sleeve has a dodecagonal sleeve surface for connecting the dodecagonal head, and the other end is detachably connected to the end of the extension rod. The end of the ratchet wrench has a dodecagonal sleeve surface for connecting the dodecagonal head. The adapter can be connected sequentially to the eccentric sleeve and the extension rod, or to the ratchet wrench, to adapt to different operational needs in various spaces.
[0007] Preferably, when the hexagonal head of the adapter mates with the hexagonal socket of the socket head cap screw, it can be rotated at a certain angle to mate with the head face, making it convenient to adjust the angle in a confined space.
[0008] Preferably, the end of the connecting rod away from the square head is provided with a square hole for connecting a torque wrench. By rotating the torque wrench, the connecting rod, the eccentric sleeve, the adapter and the internal hex bolt are rotated together.
[0009] Preferably, the end of the eccentric sleeve away from the dodecagonal sleeve surface one is provided with a square hole two, and the end of the connecting rod is a square head that mates with the square hole two.
[0010] Preferably, both sides of the eccentric sleeve are beveled.
[0011] Preferably, when connecting the adapter and the ratchet wrench, the internal hex bolt can be tightened at small angles of 5° each time, which is suitable for gradual tightening operations in confined spaces.
[0012] This utility model provides a tool for tightening hexagonal socket head cap bolts in confined engine spaces. Compared to existing technologies, its advantages are as follows: This utility model enables the tightening and disassembly of high-pressure fuel pump hexagonal socket head cap bolts using only one set of manual tools, without relying on large overhead cranes for lifting. It also ensures consistent installation torque and is easy to operate. This facilitates on-site engine maintenance for after-sales service personnel and reduces after-sales service costs. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of a tool for tightening hexagonal bolts in the confined space of an engine.
[0014] Figure 2 This is a diagram of the space around the hex bolt. Figure 1 ;
[0015] Figure 3 This is a diagram of the space around the hex bolt. Figure 2 ;
[0016] Figure 4 This is a diagram showing the installation of the ratchet wrench, adapter, and bolts. Figure 1 ;
[0017] Figure 5 This is a diagram showing the installation of the ratchet wrench, adapter, and bolts. Figure 2 ;
[0018] Figure 6 This is a diagram showing the installation of the ratchet wrench, adapter, and bolts. Figure 3 ;
[0019] Figure 7 This is a schematic diagram of the end faces of the adapter and the hex bolt. Figure 1 ;
[0020] Figure 8 This is a schematic diagram of the end faces of the adapter and the hex bolt. Figure 2 ;
[0021] Figure 9 This is a schematic diagram showing the installation and use of a ratchet wrench and adapter;
[0022] Figure 10 This is a schematic diagram of the installation of the connecting rod, eccentric sleeve, adapter, and internal hex bolts;
[0023] Figure 11 This is a schematic diagram of the hypotenuse of the eccentric sleeve;
[0024] Figure 12 This is a diagram illustrating the use of the connecting rod and eccentric sleeve. Figure 1 ;
[0025] Figure 13 This is a diagram illustrating the use of the connecting rod and eccentric sleeve. Figure 2 ;
[0026] Figure 14 This is a schematic diagram of a set of adapters with different hexagonal head sizes;
[0027] Figure 15 It is a schematic diagram of a set of eccentric sleeves with different lengths.
[0028] Attached reference numerals: 11. Connecting rod; 11A. Square hole one; 11B. Square head; 12. Eccentric sleeve; 12A. Dodecagonal sleeve face one; 12B. Square hole two; 12C. Bevel one; 12D. Bevel two; 121. Eccentric sleeve one; 122. Eccentric sleeve two; 13. Ratchet wrench; 13A. Dodecagonal sleeve face two; 14. Adapter; 14A. Dodecagonal head; 14B. Hexagonal head; 14B1. Head face one; 14B2. Head face two; 141. Adapter one; 142. Adapter two; 143. Adapter three; 2. Hex socket head cap screw; 2A. Hex socket hole; 2A1. Hole face; 3. Solenoid valve; 4. Cylinder block; 5. Engine support; 6. High-pressure fuel pump. Detailed Implementation
[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0030] This utility model discloses a tool for tightening hexagonal socket head cap screws in the confined space of an engine. The tool mainly consists of an adapter 14, an eccentric socket 12, an extension rod 11, and a ratchet wrench 13. In practical applications, especially during the installation of hexagonal socket head cap screws 2, this tool demonstrates significant advantages.
[0031] like Figure 1 As shown, the tool for tightening the hex socket head cap screw 2 includes an extension rod 11, an eccentric socket 12, a ratchet wrench 13, and an adapter 14. In operation, the adapter 14 is first installed into the hex socket hole 2A of the hex socket head cap screw 2, at which point the hex head 14B of the adapter 14 fits tightly into the hex socket hole 2A of the hex socket head cap screw 2. Next, the ratchet wrench 13 is inserted into the confined space below the hex socket head cap screw 2 and fitted onto the twelve-pole head 14A of the adapter 14. Because the ratchet wrench 13 has a small-angle tightening function of 5° at a time, the hex socket head cap screw 2 can be gradually tightened in a narrow space until the ratchet wrench 13 can no longer tighten it further.
[0032] When the ratchet wrench 13 can no longer tighten the screws, the next step is required. At this point, the eccentric socket 12 is fitted onto the adapter 14, and its angle and direction are adjusted according to the available space. Then, the extension rod 11 is inserted into the square hole 12B of the eccentric socket 12 and extended outwards, thus shifting the tightening point to a wider area. Finally, a torque wrench is inserted into the square hole 11A of the extension rod 11. By rotating the torque wrench, the extension rod 11, eccentric socket 12, adapter 14, and hex bolt 2 are rotated together until the hex bolt 2 reaches the specified torque.
[0033] like Figure 2-3 As shown, during installation, the hex bolt 2 of the high-pressure fuel pump 6 is obstructed from the front by the solenoid valve 3, from the left and top by the cylinder block 4, from the right by the high-pressure fuel pump 6, and from below by the engine support 5, resulting in extremely limited surrounding space. Therefore, traditional tightening tools are difficult to operate directly. This invention effectively solves this problem by shifting the tightening point to a wider space, while simultaneously ensuring a small tightening angle during operation, thus avoiding interference between the tool and the parts.
[0034] like Figure 4-8 As shown, the head of the hex socket head cap screw 2 is a hexagonal structure, while the commonly used ratchet wrench 13 is usually a dodecagonal structure. Therefore, this utility model uses an adapter 14 for transition. The head of the adapter 14 is a dodecagonal head 14A. This design makes the required circumferential angle space smaller when matching tools (the minimum adaptable angle of the dodecagonal head 14A is 360° / 12 = 30°, while the minimum adaptable angle of the hexagonal head 14B is 360° / 6 = 60°). The tail of the adapter 14 is a hexagonal head 14B, which fits tightly with the hexagonal hole 2A of the hex socket head cap screw 2. By changing the mating surfaces of the two, the hole surface 2A1 of the hex socket head cap screw 2 can contact and fit with the head surface 14B1 of the adapter 14, or it can be rotated at a certain angle to fit with the head surface 14B2. This design not only facilitates the adjustment of the angle of the adapter 14 in confined spaces, but also effectively avoids interference with surrounding parts, ensuring smooth engagement with the dodecagonal socket face 13A of the ratchet wrench 13 and the dodecagonal socket face 12A of the eccentric socket 12.
[0035] like Figure 9As shown, the hexagonal head 14B of the adapter 14 is installed in the hexagonal hole 2A of the socket head cap 2, converting the socket head cap 14B into an external dodecagonal head 14A. Then, a ratchet wrench 13 of a certain length is inserted from below the socket head cap 2, i.e., from above the engine support 5, and the dodecagonal socket face 13A of the ratchet wrench 13 is fitted onto the dodecagonal head 14A of the adapter 14. Because the ratchet wrench 13 has a small-angle tightening function of 5° at a time, the socket head cap 2 can be gradually tightened within a limited space until a certain preload torque is reached. However, due to the limited space and the limited length of the ratchet wrench 13, it cannot reach the specified high torque; therefore, an eccentric socket 12 and an extension rod 11 are needed to complete the subsequent tightening operation.
[0036] like Figure 10 and Figure 11 As shown, the design of the eccentric sleeve 12 allows the tightening point of the hexagon socket bolt 2 to be offset to a wider space, thus avoiding interference with surrounding parts. The eccentric sleeve 12 has an appropriate length, which not only avoids obstruction by the solenoid valve 3, but also avoids interference with the cylinder block 4 and the high-pressure fuel pump 6. The two sides of the eccentric sleeve 12 are designed with beveled edge 12C and beveled edge 12D. Compared with the straight edge, the beveled edge provides a larger rotation space, further reducing the possibility of interference with surrounding parts. One side of the eccentric sleeve 12 is a dodecagonal sleeve surface 12A, which facilitates use with the adapter 14; the other side is a square hole 12B, which facilitates use with the connecting rod 11.
[0037] like Figure 10-13As shown, after removing the ratchet wrench 13, select a suitable direction and angle to fit the dodecagonal socket face 12A of the eccentric socket 12 onto the dodecagonal head 14A of the adapter 14. Since both are dodecagonal structures with twelve mating surfaces, the mating surfaces can be selected at a minimum angle of 360° / 12 = 30°, thereby adjusting the angle of the eccentric socket 12 to ensure smooth installation in confined spaces and avoid interference with surrounding parts. Next, fit the square head 11B of the connecting rod 11 into the square hole 12B of the eccentric socket 12. Due to the eccentricity between the square hole 12B and the dodecagonal socket face 12A of the eccentric socket 12, the connecting rod 11 can effectively avoid obstruction by the solenoid valve 3. The length of the connecting rod 11 exceeds the length of the high-pressure fuel pump 6, thus extending the operating point for tightening the hexagon socket bolt 2 to a wider operating space and avoiding interference with the high-pressure fuel pump 6. Finally, install the torque wrench into the square hole 11A of the connecting rod 11. By rotating the torque wrench, the connecting rod 11, eccentric socket 12, adapter 14, and socket head cap 2 will rotate together from position 1 to position 2, thus tightening the socket head cap 2 to the specified torque. Since the socket head cap 2 has already been pre-tightened using the ratchet wrench 13 and adapter 14 in the previous step, only a small tightening angle is needed to achieve the specified torque in this step, and the entire tool set will not interfere with the engine cylinder block 4 and the high-pressure fuel pump 6. In addition, all connections of the entire tool set are rigid connections, ensuring the lossless transmission of tightening torque during the tightening of the socket head cap 2.
[0038] When disassembling the socket head cap screw 2, first use the adapter 14, eccentric socket 12, extension rod 11 and torque wrench to loosen the socket head cap screw 2 in the opposite direction, and then use the ratchet wrench 13 and adapter 14 to unscrew the socket head cap screw 2.
[0039] This utility model is not only applicable to tightening the hexagon socket bolts 2 of the high-pressure fuel pump 6 in confined spaces, but can also be widely applied to tightening operations of hexagon socket bolts 2 in similar confined spaces. Figure 14-15 As shown, a set of adapters 14 can be designed based on this, including adapter one 141, adapter two 142, and adapter three 143. Their hexagonal heads 14B have different sizes, making them suitable for different sizes of hexagonal socket head cap screws 2. Since the positions of obstructions around the hexagonal socket head cap screws 2 vary, a set of eccentric sleeves 12 can also be designed, including eccentric sleeve one 121 and eccentric sleeve two 122. Their eccentricity between the square hole and the dodecagonal sleeve face is different, effectively avoiding the limitations imposed by different obstructions. The connecting rod 11 and the ratchet wrench 13 are interchangeable, thus forming a tool set suitable for tightening hexagonal socket head cap screws 2 of different sizes in various confined spaces.
[0040] Since the dimensions of the hex bolts 2 vary for different engines and the locations of obstacles differ, different tools are required for installation, causing inconvenience to the aftermarket. Therefore, a universal design is adopted, which can be assembled and adapted to cover more models.
[0041] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A tool for tightening hexagonal socket head cap bolts in the confined space of an engine, characterized in that, The device includes an adapter (14), an eccentric sleeve (12), a connecting rod (11), and a ratchet wrench (13). One end of the adapter (14) is a hexagonal head (14B) for connecting an internal hexagonal bolt (2), and the other end is a dodecagonal head (14A). One end of the eccentric sleeve (12) is provided with a dodecagonal sleeve surface one (12A) for connecting the dodecagonal head (14A), and the other end is detachably connected to the end of the connecting rod (11). The end of the ratchet wrench (13) is provided with a dodecagonal sleeve surface two (13A) for connecting the dodecagonal head (14A). The adapter (14) can be connected to the eccentric sleeve (12) and the connecting rod (11) in sequence, or to the ratchet wrench (13), to adapt to the operational needs of different spaces.
2. The hexagonal bolt tightening tool for use in confined spaces within an engine, as described in claim 1, is characterized in that... When the hexagonal head (14B) of the adapter (14) is engaged with the internal hexagonal hole (2A) of the internal hexagonal bolt (2), it can be rotated at a certain angle to engage with the head face (14B2), which facilitates the adjustment of the angle in a narrow space.
3. A tool for tightening hexagonal socket head cap bolts in a confined space of an engine, as described in claim 1 or 2, characterized in that... The end of the connecting rod (11) away from the square head (11B) is provided with a square hole (11A) for connecting a torque wrench. By rotating the torque wrench, the connecting rod (11), the eccentric sleeve (12), the adapter (14) and the internal hex bolt (2) will rotate together.
4. A tool for tightening hexagonal socket head cap bolts in a confined space of an engine, as described in claim 3, is characterized in that... The eccentric sleeve (12) has a square hole (12B) at the end away from the dodecagonal sleeve surface (12A), and the end of the connecting rod (11) is a square head (11B) that mates with the square hole (12B).
5. A tool for tightening hexagonal socket head cap bolts in a confined space of an engine, as described in claim 4, is characterized in that... Both sides of the eccentric sleeve (12) are inclined.
6. A tool for tightening hexagonal socket head cap bolts in a confined space of an engine, as described in claim 1 or 2, characterized in that, When connecting the adapter (14) and the ratchet wrench (13), the internal hex bolt (2) can be tightened at small angles of 5° each time, which is suitable for gradual tightening operations in confined spaces.