Assembly tool for installing crankshaft connecting rod assembly to crankcase

Abstract

The utility model relates to an assembly tool for installing a crankshaft connecting rod assembly to a crankcase, which comprises at least one roughly vertical upright post, a suspension part positioned at the upper part of each upright post and a load-carrying part positioned at the lower part of each upright post, and the load-carrying part is provided with roughly two parallel and separated load-carrying arms. In the working process, the weight bearing arm extends forwards from the rear along the left side and the right side of the lower portion of the crankshaft connecting rod assembly till the weight bearing arm reaches or exceeds the two balance wheels on each side, then the assembling tool and the crankshaft connecting rod assembly are lifted together through the hanging part on the upper portion and then moved to a crankcase, and the crankshaft connecting rod assembly is assembled. And the angle and the direction of the crankshaft connecting rod assembly are finely adjusted manually or mechanically, and the crankshaft connecting rod assembly is installed in a crankcase. According to the assembling tool, when the crankshaft connecting rod assembly is installed on a crankcase, compared with the existing mode that the crankshaft connecting rod assembly is moved and installed after being manually lifted, operation is easy and convenient, time and labor are saved, labor cost is saved, and assembling efficiency is improved.

Description

Technical Field

[0001] The utility model mainly relates to the technical field of assembly, and in particular to an assembly tool for installing a crankshaft connecting rod assembly to a crankcase. Background Art

[0002] The crankshaft is installed in the crankcase and is used to convert the reciprocating translation of the cylinder piston into the rotation of the crankshaft. Figure 1 As shown, it generally includes a thinner front end shaft 11 and a thicker rear end shaft 12. The front end shaft 11 and the rear end shaft 12 are arranged in a colinear manner and are fixed on the crankcase through a bearing 16 for rotation. The central axis of the two is the rotation axis of the crankshaft. A connecting rod journal 13 is connected between the front end shaft 11 and the rear end shaft 12, which is not coaxial but roughly parallel. The big end of the connecting rod assembly 17 is sleeved on the connecting rod journal 13 and can rotate. When working, the piston drives the big end of the connecting rod assembly 17 to rotate around the central axis together with the connecting rod journal 13, driving the crankshaft to rotate synchronously. Usually, in order to balance the rotation imbalance caused by the eccentric setting of the connecting rod journal 13, a pair of counterweights are fixed on the connecting rod journal 13, generally a pair of balance wheels 15 with a certain mass that are approximately semicircular. The balance wheel 15 is a fan-shaped structure, including an arc surface 151 and two radial surfaces 152 that are roughly flat along the radial direction. The arc surface 15 and the connecting rod journal 13 are arranged on both sides opposite to each other, so that the center of gravity of the entire crankshaft connecting rod assembly falls on the central axis, reducing vibration and noise when the crankshaft rotates.

[0003] When assembling an engine or a compressor, the connecting rod assembly 17 is usually connected to the crankshaft first to form a crankshaft connecting rod assembly, and then the crankshaft connecting rod assembly is moved into the crankcase as a whole and assembled in place. Figure 2 As shown, before being assembled into the crankcase, it is first placed on a bracket 10. Since the balance wheel 15 is heavy, the bracket 10 is usually located opposite to the two balance wheels 15, with the arc surface 151 of the balance wheel 15 located at the top and the radial surface 152 facing downward. In addition, limit rods 18 are temporarily fixed on the left and right sides of the connecting rod assembly 17 to prevent the connecting rod assembly 17 from rotating to both sides and falling when moving. The specific operation includes: firstly, the crankshaft connecting rod assembly is lifted from the bracket 10 as a whole, moved and placed into the crankcase, and then the position of the crankshaft connecting rod assembly is finely moved and adjusted until the rear end shaft 12 extends into the large opening of the crankcase. After the crankshaft connecting rod assembly is placed in place and fixed by the bearing 16, the limit rod 18 is removed, and the small ends of each connecting rod are rotated to align with the cylinder mounting holes on the upper part of the crankcase, so that the subsequent small ends of the connecting rod can be rotatably mounted on the cylinder pistons in the mounting holes of each cylinder.

[0004] Therefore, when installing a large engine or compressor, it is necessary to first move the crankshaft connecting rod assembly as a whole into the crankcase, and finely adjust the position and angle of the crankshaft connecting rod assembly until the rear end shaft 12 is inserted into the large opening of the crankcase and the bearing 16 falls into a fixed position on the crankcase, and then the entire crankshaft connecting rod assembly can be put down. In current technology, moving and adjusting the position of the crankshaft connecting rod assembly is basically done manually, but the crankshaft connecting rod assembly is usually heavy (about 50kg) and irregular in shape. Therefore, during the installation process, it is difficult to hold the crankshaft connecting rod assembly and align the two ends of the crankshaft at the same time and adjust the angle, which makes the installer more laborious. Therefore, it is very difficult to align the crankshaft connecting rod assembly with the large opening and install it into the crankcase, the installation cycle is long, and the personnel experience during the installation process is poor.

[0005] Therefore, there is an urgent need for an assembly tool that replaces manpower and is used to install the crankshaft connecting rod assembly into the crankcase. Summary of the invention

[0006] In view of the above-mentioned defects of the prior art, the purpose of the utility model is to provide an assembly tool for installing a crankshaft connecting rod assembly to a crankcase, so as to solve the technical problem that the prior art can only rely on manual handling, resulting in high labor intensity and low efficiency.

[0007] The technical solution of the utility model is as follows:

[0008] An assembly tool for installing a crankshaft connecting rod assembly to a crankcase, comprising at least one approximately vertical column, the lower part of which is provided with two approximately parallel and separated load-bearing arms, the load-bearing arms extending forward approximately horizontally and being used to be inserted under the crankshaft connecting rod assembly to jointly support the radial surfaces of two balance wheels on each side from the left and right sides; the upper part of the column is provided with a suspension structure for connecting to an external structure to move the assembly tool.

[0009] The utility model sets two approximately parallel and separated load-bearing arms, which extend forward from the rear along the left and right sides below the crankshaft connecting rod assembly until reaching or exceeding the two balance wheels on each side, and then lifts the assembly tool and the crankshaft connecting rod assembly together through the upper suspension structure, and then moves them into the crankcase, and then finely adjusts the angle and orientation of the crankshaft connecting rod assembly by manual or machine, and installs it into the crankcase. Compared with the current manual lifting, moving and installation, the technical solution of the utility model is simple and convenient to operate when installing the crankshaft connecting rod assembly to the crankcase, saving time and effort, not only saving labor costs, but also improving assembly efficiency.

[0010] Preferably, the columns are provided in two numbers, connected and fixed by a substantially horizontal cross bar; each column is provided with a load-carrying arm. Two columns are provided, connected and fixed by a cross bar, forming a stable frame structure, which can ensure the safety and stability when carrying the crankshaft connecting rod assembly. Of course, the columns can also be provided in more than two numbers.

[0011] More preferably, the length of the crossbar is adjustable. By adjusting the length of the crossbar, the distance between the uprights can be changed, thereby changing the spacing between the load-carrying arms, so as to adapt to crankshaft connecting rod assemblies of different widths.

[0012] In one embodiment, the horizontal bar includes two partially overlapping sections, and the overlapping section is provided with an open slot along the length direction, and a screw is inserted into the open slot and fixed with a nut. In this embodiment, when the spacing between the weight-carrying arms needs to be changed, it is only necessary to loosen the screw-nut connection, pull apart or press the two sections of the horizontal bar, change the overlapping length, that is, change the length of the open slot, and then tighten the screw and nut after adjusting to a suitable length. It is simple and reliable.

[0013] Of course, the length of the horizontal bar can be adjusted, and it can also be achieved through more technical solutions, for example, the horizontal bar is two cylindrical sections, one section is inserted into the other section and can be rotatably overlapped. In this way, the length of the overlapping part can be adjusted by rotation. Of course, in this embodiment, the connection between each section and the column is also rotatable.

[0014] Other technical solutions include, for example, setting the horizontal bar to be a parallelogram mesh structure, with two diagonal corners fixed on two columns respectively, so that the distance between the two columns can be changed by simple pushing and pulling.

[0015] Preferably, the upper part of the column is provided with a traction plate extending forward approximately horizontally, and the suspension structure is provided on the traction plate, and its projection in the vertical direction approximately corresponds to the position of the middle part of the load-carrying arm. By providing the traction plate and moving the suspension structure forward, it can be ensured that the center of gravity is located directly below the suspension structure when the crankshaft connecting rod assembly is lifted, thereby reducing the need for manual straightening of the crankshaft connecting rod assembly during movement, and preventing accidents such as the crankshaft connecting rod assembly tipping over due to the tilt of the load-carrying arm during movement.

[0016] More preferably, an upper reinforcing plate is fixed at the junction of the traction plate and the column, and is installed above the traction plate. Considering that there is a distance between the suspension structure and the column, a lever arm is formed, and a torque will be generated during suspension, and this torque is offset by the fixed connection between the traction plate and the column. Because the lever arm formed by the fixed connection between the traction plate and the column is very small, the upward pulling force on the root of the traction plate is very large, and it is easy to peel the traction plate from the column, causing a falling accident. Therefore, an upper reinforcing plate is added above the traction plate, the lower edge of the upper reinforcing plate is fixed to the upper surface of the traction plate, and the side of the upper reinforcing plate is fixed to the side of the upper part of the column, so that the upward pulling force on the root of the traction plate can be changed into pressure on the traction plate and the upper part of the column, thereby increasing the stability of the entire connection.

[0017] More preferably, the suspension structure includes two groups, which are fixed to the front and rear of the traction plate respectively. Two suspension points are set at the same time, and the center of gravity of the entire load-bearing arm and the crankshaft connecting rod assembly is located between the two suspension points, so that the force arm of gravity is 0 and the moment is 0, which can further prevent the possibility of overturning accidents.

[0018] In one embodiment, the column is provided with a socket that matches the cross section of the traction plate / the load-carrying arm, and the traction plate / the load-carrying arm is fixed to the column after its proximal end is inserted and extended backward from the socket. That is, the proximal end of the traction plate / the load-carrying arm is inserted into the column to be fixed, and the torque acting on the traction plate / the load-carrying arm is offset by the strength of the traction plate / the load-carrying arm itself and the strength of the socket wall, so that the traction plate / the load-carrying arm can be prevented from being peeled off from the column under the heavy pressure of the crankshaft connecting rod assembly.

[0019] Preferably, it also includes an anti-skid plate fixed to the distal end of the weight-carrying arm, the upper edge of the anti-skid plate being slightly higher than the upper surface of the weight-carrying arm, for preventing the crankshaft connecting rod assembly from sliding off the distal end of the weight-carrying arm. The anti-skid plate is provided to directly block the crankshaft connecting rod assembly when it is placed on the weight-carrying arm to prevent the crankshaft connecting rod assembly from sliding off.

[0020] Preferably, a lower reinforcing plate is further included, which is fixedly connected to the load-bearing arm and the column. The lower reinforcing plate can increase the stability of the fixed connection between the load-bearing arm and the column. The lower reinforcing plate can be arranged above the load-bearing arm to make the structure more compact; it can also be arranged below the load-bearing arm to convert the pressure of the crankshaft connecting rod assembly on the load-bearing arm into pressure on the column.

[0021] The upper reinforcing plate and the lower reinforcing plate are preferably in the form of a right-angled triangle, and the two right-angled sides are respectively fixedly connected to the traction plate / the load-bearing arm and the column, so as to further ensure the firmness of the connection.

[0022] Preferably, the column is also provided with a movable handle for finely adjusting the position and angle of the load-carrying arm. The movable handle is provided to facilitate manual operation. Because the entire assembly tool and the crankshaft connecting rod assembly are in a suspended state, it is easy to manually adjust their orientation to align with the large opening of the crankcase and place it in the crankcase.

[0023] Preferably, a positioning device is provided at the distal end of the load-bearing arm for finely adjusting the position and angle of the load-bearing arm. A positioning device, such as an acoustic or optical probe, a 3D positioning sensor, a satellite, a remote sensing or an infrared positioning probe, is provided to monitor the real-time position and posture of the load-bearing arm and to provide real-time feedback to the control mechanism to control the movement of the external structure, so that the position and posture of the load-bearing arm and / or the crankshaft connecting rod assembly can be precisely adjusted, and the crankshaft connecting rod assembly can be automatically installed to the crankcase throughout the entire process.

[0024] In one embodiment, the load-bearing arm includes a pad located at the top for contacting the radial surface, and at least one load-bearing plate located in the lower vertical direction. In other words, considering the heavy weight of the crankshaft connecting rod assembly, the load-bearing arm is specifically designed to bear the gravity by the load-bearing plate placed in the lower vertical direction, while the pad at the top is only used to contact and hold up the crankshaft connecting rod assembly. Such a design can reduce the weight of the load-bearing arm itself and improve the strength of the load-bearing arm.

[0025] Preferably, the inclination angle of the pad is the same as that of the radial surface. Theoretically, the pad can be of any shape, but it must be able to prevent the crankshaft connecting rod assembly from sliding off by contact. Therefore, the pad preferably has a surface that can fit the radial surface, which can prevent scratches on the radial surface and stabilize the crankshaft connecting rod assembly.

[0026] Preferably, the pad is covered with an anti-slip elastic material layer. Adding the elastic material layer can increase friction and prevent slipping on the one hand, and also buffer and protect the extrusion and friction between the radial surface and the pad on the other hand.

[0027] In one embodiment, the suspension structure is a suspension ring, which is simple and reliable to provide a suspension ring in conjunction with an external structure such as a cable.

[0028] The utility model also discloses a working method of the assembly tool, which comprises:

[0029] The two weight-carrying arms extend from the left and right sides to the bottom of the crankshaft connecting rod assembly respectively; each weight-carrying arm reaches or exceeds the two balance wheels on each side; the suspension structure lifts the assembly tooling and the crankshaft connecting rod assembly; the suspension structure moves the assembly tooling and places the weight-carrying arm and the crankshaft connecting rod assembly into the crankcase; after adjusting the position of the crankshaft connecting rod assembly, it is fixed to the crankcase; the suspension structure lowers and moves the assembly tooling to withdraw the weight-carrying arm from the crankcase. The following will explain the present utility model in detail in combination with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the crankshaft;

[0031] Figure 2 It is a structural schematic diagram of a crankshaft connecting rod assembly;

[0032] Figure 3 It is a structural schematic diagram of the assembly tooling of the utility model;

[0033] Figure 4 It is a structural schematic diagram of the load-bearing arm in the assembly tooling of the utility model;

[0034] Figure 5 This is a structural schematic diagram of the utility model assembly tool loading the crankshaft connecting rod assembly;

[0035] Figure 6 This is a schematic diagram of the utility model after the assembly tool places the crankshaft connecting rod assembly into the crankcase;

[0036] In the figure: 10- bracket, 11- front end shaft, 12- rear end shaft, 13- connecting rod journal, 15- balance wheel, 151- arc surface, 152- radial surface, 16- bearing, 17- connecting rod assembly, 18- limit rod, 20- column, 21- traction plate, 22- cross bar, 23- direction handle, 24- upper reinforcement plate, 25- load-bearing arm, 250- socket, 251- load-bearing plate, 252- pad, 253- anti-skid plate, 254- lower reinforcement plate, 26- lifting ring, 30- crankcase, 31- cylinder mounting hole. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of the present invention, the present invention will be described in more detail below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings, but the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.

[0038] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to another element or there may be a central element at the same time. The terms "vertical", "positive", "negative" and similar expressions used in this article are based on the direction or position relationship shown in the drawings. This is only for the convenience of description, and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0039] In addition, it should be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which the present invention belongs. The terminology used in the specification of the present invention is for the purpose of describing specific embodiments and is not intended to limit the present invention.

[0041] The utility model discloses an assembly tool for installing a crankshaft connecting rod assembly to a crankcase, which is used to replace the existing technology that completely relies on manual labor. The assembly tool of the utility model has an overall structure as follows Figure 3 As shown, it includes two parts, a suspension part located at the upper part and a weight-bearing part located at the lower part, and the two parts are connected by at least one substantially vertical column 20 to form a whole.

[0042] The suspension part may only include a suspension structure, such as a lifting ring 26, fixed on the upper part of the column 20, so that it can be conveniently connected to an external structure, such as a cable, and after being lifted, the assembly tool is moved to the front of the bracket 10 to perform the task of loading the crankshaft connecting rod assembly onto the load-bearing part, and the subsequent task of moving the load-bearing part loaded with the crankshaft connecting rod assembly into the crankcase. More preferably, considering that the large weight of the crankshaft connecting rod assembly will generate a large torque on the lower load-bearing part, causing the assembly tool to tilt or even overturn, a traction plate 21 extending forward approximately horizontally is first fixed on the upper part of the column 20, and the suspension structure is arranged on the traction plate 21, and the projection in the vertical direction roughly corresponds to the position of the middle part of the lower load-bearing part. In this way, the center of gravity of the entire assembly tool and the crankshaft connecting rod assembly is kept roughly directly below the external structure and the suspension structure, so as to reduce the possibility of overturning caused by the torque of gravity on the assembly tool. In a more preferred embodiment, the suspension structure can be provided in two groups, which are respectively fixed to the front center and the rear center of the traction plate 21, so as to keep the gravity between the two groups of suspension structures to prevent the possibility of overturning accidents. Of course, more groups of suspension structures can also be provided in a dispersed manner.

[0043] In order to prevent the traction plate 21 from peeling off the column 20 due to the large gravity moment on the assembly tool, an upper reinforcing plate 24, such as a right-angled triangle rigid plate, is fixed above the traction plate 21. The lower edge of the upper reinforcing plate 24 is fixed to the upper surface of the traction plate 21, and the side of the upper reinforcing plate 24 is fixed to the side of the upper part of the column 20, especially by insertion. In this way, the upward pulling force on the root of the traction plate 21 is changed into pressure on the traction plate 21 and the upper part of the column 20, thereby increasing the stability of the entire connection.

[0044] The weight-bearing part is fixed to the lower part of the column 20 and is used to lift the crankshaft connecting rod assembly. It includes two weight-bearing arms 25 extending horizontally forward. The two weight-bearing arms 25 are separated in parallel to facilitate insertion from the left and right sides of the crankshaft and between the crankshaft connecting rod assembly and the bracket 10. Specifically, after the assembly tool is lifted, it is first moved to the crankshaft connecting rod assembly placed on the bracket 10, located on the side of the front end shaft 11 of the crankshaft, and the two weight-bearing arms 25 are lower than the lower part of the balance wheel 15 and face the left and right sides of the balance wheel 15 forward. Then the assembly tool is moved forward and the weight-bearing arms 25 are kept directly below the two balance wheels 15. Then, along the length direction of the crankshaft, the weight-bearing arms 25 are inserted from the front end shaft 11 to the rear end shaft 12, at least exceeding the position of the balance wheel 15 on the front end shaft 11. Then, the external structure lifts the assembly tool and the crankshaft connecting rod assembly upward through the suspension structure, and moves them to the crankcase for assembly.

[0045] Because the crankshaft connecting rod assembly is usually heavy, and the load-bearing arm 25 is only fixed to the column 20 at one end, the torque on the fixed part between the load-bearing arm 25 and the column 20 is very large. Therefore, it is necessary to consider the structural design of the load-bearing arm 25 itself, and more preferably, the reinforcement design of the connection between the load-bearing arm 25 and the column 20 should also be considered. In a preferred embodiment, the specific structure of the load-bearing arm 25 is as follows: Figure 4 As shown, it includes a pad 252 located at the top for contacting the radial surface 152 and at least one load-bearing plate 251 located in the vertical direction. The height of the load-bearing plate 251 in the vertical direction is greater than the width in the horizontal direction. And, more preferably, the load-bearing plate 251 can be set as a plurality of parallel plates in the vertical plane, ( Figure 4 3 blocks are shown in the figure) to share the weight of the crankshaft connecting rod assembly on the load-bearing arm 25.

[0046] A reinforcement structure may also be provided at the connection between the load-carrying arm 25 and the column 20. Figure 4 As shown, a lower reinforcing plate 254 is provided below the load-carrying arm 25, one side of the lower reinforcing plate 254 is fixed to the side column 20, and the other side is fixed to the lower surface of the upper load-carrying arm 25. The lower reinforcing plate 254 is preferably designed as a long strip structure, fixed to the lower surface of the distal end of the load-carrying arm 25 and the side of the column 20.

[0047] In a more preferred embodiment, the column 20 is provided with a socket 250 that matches the cross section of the load-carrying arm 25, and the proximal end of the load-carrying arm 25 is inserted into and extended out of the socket 250 and then fixed to the column 20. By inserting the proximal end of the load-carrying arm 25 into the column 20, the moment at the connection between the load-carrying arm 25 and the column 20 is fully borne by the strength of the load-carrying arm 25 itself and the material strength of the socket 250, and the reliability is higher.

[0048] In a more preferred embodiment, in order to prevent the crankshaft connecting rod assembly from sliding off the load-bearing arm 25, firstly, the width direction of the pad 252, that is, the left and right tilt angle, can be designed to be the same as the radial surface 152 to ensure that it can completely fit the radial surface 152. Secondly, an anti-skid structure can be set on the load-bearing arm 25, at least on the pad 252, such as adding transverse stripes, protrusions, etc. It can also be set with an anti-skid net, anti-skid sleeve, etc. It is more preferred to cover the pad 252 with an anti-skid elastic material layer, such as rubber, etc. This not only prevents slipping, but also can buffer and protect the surface of the radial surface 152 and the pad 252.

[0049] In order to prevent the crankshaft connecting rod assembly from sliding, in one embodiment, an anti-skid plate 253 is fixed to the far end of the load-bearing arm 25, and the upper edge height of the anti-skid plate 253 is slightly higher than the pad 252, which can prevent the crankshaft connecting rod assembly from sliding down.

[0050] Among them, the column 20 can be one or two, but preferably two. This makes it convenient to install two parallel weight-carrying arms 25 at a certain distance, that is, the two columns 20 are separated by a roughly horizontal cross bar 22 and set at a set distance, and a weight-carrying arm 25 is installed at the lower part of each column 20. In this way, it is also easy to adjust the spacing between the two weight-carrying arms 25 by changing the length of the cross bar 22 to adapt to crankshaft connecting rod assemblies of different widths, and ensure that the weight-carrying arms 25 are accurately inserted into the two radial surfaces 152 of the balance wheel 15 along the left and right sides of the crankshaft. When the cross bar 22 is selected to be adjustable in length, the distance between the two columns 20 can be adjusted by changing the length of the cross bar 22. For example, in one embodiment, the cross bar 22 includes two partially overlapping sections, and the length of the overlapping section can be adjusted by stretching or squeezing the two sections. At the same time, an open groove along the length direction of the cross bar 22 is set in the overlapping section, and a screw is inserted in the open groove to match a nut. In this way, after adjusting the length of the overlapping section, it can be tightened by matching the screw and nut. In another embodiment, the crossbar 22 is divided into two sections. If a cylindrical shape is selected, one section can be inserted into the other section for rotation, and the two sections are connected by a threaded sleeve; other shapes can also be realized by adding other structures between the two sections that can change the insertion depth of the two sections, such as a screw. In a more preferred embodiment, the two columns 20 can also be connected by a parallelogram mesh structure, and at least part of the intersection points of the mesh structure can be fixed, so that it is very convenient to adjust the distance between the two weight-bearing arms 25 by pushing and pulling one or two columns 20 to adapt to crankshaft connecting rod assemblies of different widths.

[0051] After the crankshaft connecting rod assembly is loaded on the assembly tool, Figure 5 As shown, the weight-carrying arms 25 on both sides lift the crankshaft connecting rod assembly from directly below the balance wheel 25, keeping the rear end shaft 12 facing forward, while the connecting rod assembly 17 is constrained by the limit rods 18 on both sides, so that the small head is kept at the top, which is convenient for connecting to the piston. Then the assembly tool carries the crankshaft connecting rod assembly and moves to the rear of the crankcase 30 following the external structure, as shown in FIG. Figure 6 As shown, the load-carrying arm 25 together with the crankshaft connecting rod assembly loaded thereon is extended into the crankcase 30, and then the precise orientation of the crankshaft connecting rod assembly is adjusted, for example, manually through the direction handle 23, or automatically by the positioning device, so that the rear end shaft 12 is inserted into the front large opening of the crankcase 30. After being placed in place, it is contacted and fixed with the crankcase 30 through the bearing 16, and then the limit rod 18 is removed, and then each connecting rod is rotated until the connecting rod small head is aligned with each cylinder mounting hole 31, and the installation can be completed. The connecting rod small head will be rotatably mounted on the cylinder piston in each cylinder mounting hole 31. In the embodiment of the accompanying drawings, three connecting rods and three cylinder mounting holes 31 distributed in three directions are shown.

[0052] Therefore, the assembly tool of the utility model, when working, has the following steps:

[0053] The two weight-carrying arms 25 extend from the left and right sides to the bottom of the crankshaft connecting rod assembly 17 respectively; each weight-carrying arm 25 reaches or exceeds the two balance wheels 15 on each side; the suspension structure lifts the assembly tooling and the crankshaft connecting rod assembly 17; the suspension structure moves the assembly tooling to place the weight-carrying arms 25 and the crankshaft connecting rod assembly 17 into the crankcase 30; after adjusting the posture of the crankshaft connecting rod assembly 17, it is fixed to the crankcase 30; the suspension structure lowers and moves the assembly tooling to withdraw the weight-carrying arms 25 from the crankcase 30. The above description of the utility model in combination with the accompanying drawings is exemplary, and it is obvious that the specific implementation of the utility model is not limited by the above method. As long as the non-substantial improvement is made by adopting the method concept and technical solution of the utility model, or the concept and technical solution of the utility model are directly applied to other occasions without improvement, they are all within the protection scope of the utility model.

Claims

1. An assembly tool for mounting a crankshaft connecting rod assembly to a crankcase, characterized in that: It comprises at least one substantially vertical column, the lower part of which is provided with two substantially parallel and separated load-bearing arms, which extend forward substantially horizontally and are used for being inserted under the crankshaft connecting rod assembly to jointly support the radial direction of the two balance wheels on each side from the left and right sides; the upper part of the column is provided with a suspension structure for connecting an external structure to move the assembly tooling.

2. The assembly tool according to claim 1, characterized in that: The columns are provided in two numbers and are connected and fixed by a substantially horizontal cross bar; each column is provided with a load-bearing arm.

3. The assembly tool according to claim 2, characterized in that: The length of the crossbar is adjustable.

4. The assembly tool according to any one of claims 1 to 3, characterized in that: The upper part of the column is provided with a traction plate extending forward approximately horizontally. The suspension structure is arranged on the traction plate, and its projection in the vertical direction approximately corresponds to the position of the middle part of the load-bearing arm.

5. The assembly tool according to claim 4, characterized in that: The suspension structure comprises two groups, which are respectively fixed to the front and rear of the traction plate.

6. The assembly tool according to claim 4, characterized in that: An upper reinforcing plate is also fixed at the junction of the traction plate and the column and is installed above the traction plate.

7. The assembly tool according to claim 4, characterized in that: The column is provided with a socket matching the cross section of the traction plate / the load-bearing arm. The traction plate / the load-bearing arm is inserted through its proximal end and extends backwards from the socket and is fixed on the column.

8. The assembly tool according to claim 1, characterized in that: It also includes an anti-skid plate fixed to the distal end of the weight-bearing arm, wherein the upper edge of the anti-skid plate is slightly higher than the upper surface of the weight-bearing arm, and is used to prevent the crankshaft connecting rod assembly from sliding off the distal end of the weight-bearing arm.

9. The assembly tool according to claim 1, characterized in that: It also includes a lower reinforcing plate, which is fixedly connected to the load-bearing arm and the column.

10. The assembly tool according to claim 1, characterized in that: A movable handle is provided on the column, or a positioning device is provided at the far end of the load-bearing arm, which is used for finely adjusting the position and angle of the load-bearing arm.

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