Crankshaft assembly, pump body assembly and compressor

Abstract

This application provides a crankshaft assembly, a pump body assembly, and a compressor. The crankshaft assembly includes a crankshaft with an eccentric portion; the eccentric portion has a groove on its side away from the crankshaft axis, the groove extending in an axial direction through the crankshaft; in the cross-section of the crankshaft, the depth direction of the groove includes a circumferentially extending portion. The groove in the eccentric portion allows a portion of the eccentric portion to undergo flexible deformation, reducing the contact load between the eccentric portion and the rollers, and reducing friction and wear.

Description

Technical Field

[0001] This application belongs to the field of compressor technology, specifically relating to a crankshaft assembly, a pump body assembly, and a compressor. Background Technology

[0002] With the development of high speed and miniaturization, compressors are characterized by high oil discharge and slow oil return. The problem of insufficient oil on the relatively moving surfaces of pump body parts is becoming increasingly apparent. The lubrication of friction pairs is weakened, resulting in insufficient oil or even dry friction. This leads to increased surface wear and frictional power consumption, resulting in reduced compressor energy efficiency and decreased reliability. In particular, the eccentric part of the crankshaft drives the rollers to rotate and undergoes relative sliding. The surface of the eccentric part is extremely prone to poor lubrication, and under high contact stress with the rollers, material wear failure occurs. Summary of the Invention

[0003] Therefore, this application provides a crankshaft assembly, a pump body assembly, and a compressor that can solve the problem of material wear between the crankshaft eccentric part and the rollers in the prior art.

[0004] To address the aforementioned problems, this application provides a crankshaft assembly, comprising:

[0005] Crankshaft, including an eccentric section;

[0006] The eccentric portion has a groove on its side away from the crankshaft axis, and the groove extends along the axial direction of the crankshaft; on the cross-section of the crankshaft, the depth direction of the groove includes a circumferentially extending portion.

[0007] Optionally, the crankshaft is provided with a central oil hole, and the bottom of the groove communicates with the central oil hole.

[0008] Optionally, the crankshaft is provided with a radial oil hole, which connects the bottom of the groove and the central oil hole.

[0009] Optionally, the depth direction of the groove from the opening to the bottom is the same as the rotation direction of the crankshaft.

[0010] Optionally, the surface of the crankshaft is provided with at least one of a coating or a texture.

[0011] Optionally, the coating includes one or a combination of hard coating and soft coating, wherein the hard coating is a DLC coating or a ceramic coating, and the soft coating is at least one of PTFE coating, PEEK coating, MoS2 coating, WS2 coating, BaF2 coating, CaF2 coating and GLC coating.

[0012] Optionally, the hard coating is prepared by any of the following methods: coating, plating, carburizing, nitriding, and surface heat treatment; or / and the soft coating is prepared by any of the following methods: coating, plating, phosphating, and sulfidation.

[0013] Optionally, the coating is a combination of a hard coating and a soft coating, with the outermost layer being the soft coating.

[0014] Optionally, the texture includes at least one of groove type and microporous type, wherein the groove type is grid type, straight type or spiral type; and the microporous type is circular hole, elliptical hole, triangular hole, rhomboid hole, square hole, rectangular hole or honeycomb hole.

[0015] Optionally, the depth of the texture is 2 to 100 μm, and the area ratio of the texture is 0.02 to 0.85.

[0016] According to another aspect of this application, a pump body assembly is provided, including the crankshaft assembly as described above.

[0017] According to another aspect of this application, a compressor is provided, including the crankshaft assembly as described above or the pump body assembly as described above.

[0018] This application provides a crankshaft assembly, comprising: a crankshaft including an eccentric portion; the eccentric portion having a groove on a direction away from the crankshaft axis, the groove extending in an axial direction through the crankshaft; and on the cross-section of the crankshaft, the groove including a circumferentially extending portion in the depth direction.

[0019] This application provides a groove in the eccentric part, which allows a portion of the eccentric part to undergo flexible deformation, reducing the contact load between the eccentric part and the roller, and reducing friction and wear. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a rotary compressor according to an embodiment of this application;

[0021] Figure 2 This is a schematic diagram of the crankshaft assembly according to an embodiment of this application;

[0022] Figure 3 This is a schematic diagram of the crankshaft assembly from another perspective, according to an embodiment of this application.

[0023] Figure 4 This is a schematic cross-sectional view of the crankshaft assembly according to an embodiment of this application;

[0024] Figure 5 This is a force analysis diagram of the cross-sectional structure of the crankshaft assembly according to an embodiment of this application;

[0025] Figure 6 This is a schematic diagram of the textured coating coupling treatment structure according to an embodiment of this application;

[0026] Figure 7 This is a schematic diagram of the coating structure under stress and deformation according to an embodiment of this application;

[0027] Figure 8 This is a schematic diagram of the stress and deformation of the coating under extrusion damage according to an embodiment of this application;

[0028] Figure 9 This is another structural schematic diagram of the crankshaft assembly according to an embodiment of this application;

[0029] Figure 10 This is a schematic diagram of the textured coating coupling treatment structure according to an embodiment of this application;

[0030] Figure 11 This is a schematic diagram of the textured coating coupling treatment structure according to an embodiment of this application.

[0031] The reference numerals in the attached figures are as follows:

[0032] 01. Substrate; 02. Coating; 03. Texture; 04. Extrusion damage; 11. Crankshaft; 12. Main bearing; 13. Secondary bearing; 14. Roller; 111. Long shaft section of crankshaft; 112. Eccentric part of crankshaft; 113. Short shaft end of crankshaft; 114. Crankshaft axis; 115. Eccentric part of crankshaft near the axis; 116. Eccentric part of crankshaft away from the axis; 117. Central oil hole; 118. Radial oil outlet; 119. Eccentric groove. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0035] See also Figures 1 to 11 As shown, according to an embodiment of this application, a crankshaft assembly includes:

[0036] Crankshaft 11, including an eccentric portion;

[0037] The eccentric portion has a groove on the axis away from the crankshaft 11, and the groove extends in the axial direction through the crankshaft 11; on the cross-section of the crankshaft 11, the depth direction of the groove includes a circumferentially extending portion.

[0038] This application provides a groove in the eccentric part, which allows a portion of the eccentric part to undergo flexible deformation, reducing the contact load between the eccentric part and the roller 14, and reducing friction and wear.

[0039] Because the eccentric part has a groove, the groove extends axially through the eccentric part, and the groove depth includes a circumferential part, so that the outer part of the groove is deformable. When subjected to radial compression by the outer circumferential roller 14, it can undergo flexible deformation, which can reduce the contact load and friction wear between the eccentric part and the roller 14.

[0040] The depth direction of the groove includes straight and curved types, with straight types being easier to process.

[0041] In some embodiments, the crankshaft 11 is provided with a central oil hole 117, and the bottom of the groove communicates with the central oil hole 117.

[0042] The crankshaft 11 is provided with a central oil hole 117, which is usually used to provide lubricating oil to the crankshaft 11 and its components. In this application, the bottom of the groove is directly connected to the central oil hole 117, which can guide the lubricating oil to the eccentric part and the roller 14, providing sufficient lubrication to the eccentric part and reducing wear.

[0043] In some embodiments, the crankshaft 11 is provided with a radial oil hole, which connects the bottom of the groove and the central oil hole 117.

[0044] The bottom of the groove and the central oil hole 117 are connected by setting radial oil holes. The radial oil holes can be set as blind holes, with the open end away from the bottom of the groove and on the other side of the eccentric part, so as to guide the lubricating oil to flow into this place.

[0045] When the crankshaft 11 rotates, the central oil hole 117 pumps oil upward to the eccentric part and flows out from the radial oil outlet 118 of the eccentric part. A portion of the lubricating oil enters the groove through the radial oil hole connected to the groove and flows out of the groove with the rotation of the crankshaft 11 to the eccentric part and the mating surface with the roller 14 for lubrication.

[0046] In some embodiments, the groove extends from the opening to the bottom in the same direction as the rotation direction of the crankshaft 11.

[0047] When setting the opening orientation of the groove, the depth direction of the groove from the opening to the bottom should be the same as the rotation direction of the crankshaft 11. This allows the lubricating oil to flow smoothly from the groove to the friction surface between the eccentric part and the roller 14 for lubrication. If the orientation is reversed, the lubricating oil will be blocked from flowing out and there will be no lubrication effect.

[0048] In some embodiments, the surface of the crankshaft 11 is provided with at least one of coating 02 or texture 03.

[0049] Due to the deformation of the outer side of the groove, this deformation repeats periodically when the crankshaft 11 rotates at high speed, which can easily cause the coating 02 on the surface of the roller 14 and the eccentric part to fall off or peel off. In order to further enhance the bonding strength between the coating 02 and the substrate, the surface of the crankshaft 11 adopts a structure that combines the coating 02 and the texture 03 to improve the stability of the parts.

[0050] A micro-texture 03 structure is prepared on the material surface, and a soft-hard alternating superimposed coating 02 is prepared. The texture 03 increases the surface area in contact with the coating 02, enhances the adhesion between the coating 02 and the substrate 01. The multi-layer coating 02 is stacked with alternating soft and hard layers. The hard layer is wear-resistant and provides support for the soft layer. The soft layer has a certain elasticity, increases interlayer slip, and has self-lubricating properties. When subjected to stress, the soft layer plays a contact stress buffering role, transforming the original rigid contact into an elastic contact. Interlayer interface slip can prevent crack propagation and reduce the risk of peeling.

[0051] In some embodiments, the coating 02 comprises one or a combination of a hard coating and a soft coating, wherein the hard coating is a DLC coating or a ceramic coating, and the soft coating is at least one of a PTFE coating, a PEEK coating, a MoS2 coating, a WS2 coating, a BaF2 coating, a CaF2 coating, and a GLC coating. Preferably, the hard coating is prepared by any of the following methods: coating, plating, carburizing, nitriding, and surface heat treatment; and / or the soft coating is prepared by any of the following methods: coating, plating, phosphating, and sulfidation. More preferably, the coating is a combination layer of a hard coating and a soft coating, with the soft coating being the outermost layer. Ceramic coatings include CrN, WC, TiCN, FeB, Al2O3, etc.

[0052] "Coating 02" here is a general term, not limited to material coating or plating. It can also refer to any method that alters material properties through physical or chemical means, such as surface heat treatment, sulfurizing, or nitriding. The coating employs an alternating layering of hard and soft materials, with at least one coating layer on the substrate. From the base layer to the surface, a hard coating is applied first, followed by a soft coating, and this process is repeated. A single-layer coating can be either a hard or soft coating, or both can be applied simultaneously. In a multi-layer coating structure, the base layer is ensured to be a hard coating, and the surface layer a soft coating.

[0053] Coating 02 employs an alternating layering of hard and soft layers. The hard layers are wear-resistant and provide support for the soft layers, while the soft layers increase interlayer slippage, possess self-lubricating properties, and reduce friction. This alternation of hard and soft layers gives the entire coating structure multi-layer slippage characteristics, resulting in better friction reduction performance. Simultaneously, the soft layers have a certain degree of elasticity, acting as a buffer against contact forces, and also providing cushioning between layers. Furthermore, the multi-layer coating can prevent crack propagation, reduce the risk of coating peeling induced by flexible deformation of grooves, and avoid direct damage to the substrate in the event of failure. The substrate has at least one layer of coating structure.

[0054] When abnormal wear occurs, the alternating hard and soft multilayer coatings transform the rigid contact of the original pair into the elastic contact of the existing pair. The hard coating has strong wear resistance, and the alternating hard and soft coatings take into account both wear reduction and wear resistance characteristics, which can effectively improve the problem of abnormal friction and wear on the end face.

[0055] In some embodiments, the texture 03 includes at least one of groove type and microporous type, wherein the groove type is grid-shaped, linear, or spiral; the microporous type is circular, elliptical, triangular, rhomboid, square, rectangular, or honeycomb-shaped. Preferably, the depth of the texture 03 is 2–100 μm, and the area ratio of the texture 03 is 0.02–0.85. The area ratio of the texture 03 refers to the ratio of the total area of ​​the texture 03 to the total area of ​​the lubrication distribution area of ​​the texture 03.

[0056] The micropores of Texture 03 can store lubricating oil and provide lubrication under low-oil conditions. The significant hydrodynamic effect provided by Texture 03 enhances the oil film's load-bearing capacity, ensures lubrication reliability, reduces friction, and avoids oil film rupture caused by changes in operating conditions or external disturbances during operation. The depth of Texture 03 is an important parameter affecting its effect, but precise control of the depth during processing is difficult, and its depth usually deviates from the design value. Coating 02 can be used to assist in controlling its processing depth.

[0057] The combination of texture 03 and coating 02 can be achieved by first processing texture 03 on substrate 01 and then preparing coating 02, or by preparing coating 02 first and then processing texture 03, or by first preparing a portion of coating 02, then processing texture 03, and finally preparing the remaining coating 02. The combination of coating 02 and texture 03 has two advantages: firstly, texture 03 increases the surface contact area and enhances the adhesion of coating 02; secondly, due to the different processability of different materials, single-layer or multi-layer coating 02 is beneficial for controlling the depth of texture 03.

[0058] The crankshaft 11 assembly of this application has the following effects:

[0059] Firstly, the flexible deformation of the groove can reduce the contact load between the eccentric part and the roller 14, thereby reducing friction and wear on the eccentric part.

[0060] Secondly, the eccentric groove 119 is connected to the radial oil outlet 118 of the crankshaft 11, providing sufficient lubrication for the mating surfaces of the eccentric part and the bearing.

[0061] Thirdly, the combination of texture 03 and coating 02 solves the problem of peeling damage between coating 02 and substrate that may be induced by the flexible deformation of the groove. The surface texture 03 of the material increases the surface area in contact with coating 02, enhances the adhesion between coating 02 and substrate 01, and prevents coating 02 from falling off.

[0062] Fourth: The micropores of the texture 03 can store lubricating oil and provide lubrication under low-oil conditions;

[0063] Fifth: The significant dynamic pressure effect provided by texture 03 enhances the oil film bearing capacity, ensures lubrication reliability, and avoids oil film rupture caused by changes in operating conditions or external disturbances during operation.

[0064] Sixth: The multi-layer coating 02 alternates between hard and soft layers. The hard layer is wear-resistant and provides support for the soft layer, while the soft layer increases interlayer slippage and has self-lubricating properties, reducing friction.

[0065] Seventh: The multi-layer coating 02 alternates between soft and hard layers. The soft layer has a certain elasticity, which plays a role in buffering the contact force and transforming the original rigid contact into elastic contact, thus improving abnormal wear on the end face.

[0066] Eighthly: Multi-layer coating 02 can prevent crack propagation and avoid direct damage to the base layer when damage occurs, thus playing a protective role.

[0067] Ninth: Single or multi-layer coatings 02 can assist in the precise control of the texture 03 processing depth.

[0068] According to another aspect of this application, a pump body assembly is provided, including the crankshaft assembly as described above.

[0069] According to another aspect of this application, a compressor is provided, including the crankshaft assembly as described above or the pump body assembly as described above.

[0070] like Figure 1 As shown, the compressor includes a crankshaft 11, a main bearing 12, a secondary bearing 13, and rollers 14. The main bearing 12 is mounted on the long shaft section 111 of the crankshaft, the secondary bearing 13 is mounted on the short shaft section 113 of the crankshaft, and the rollers 14 are mounted on the eccentric part 112 of the crankshaft.

[0071] The crankshaft eccentric portion 112 of the compressor is located at position 116 groove 119 away from axis 114. The groove 119 is through in the axial direction and extends in the circumferential and radial directions. The groove 119 is open on one side in the radial direction and connected to the eccentric portion 112 on the other side. And / or the eccentric portion 112 or other surfaces of the crankshaft are prepared by coupling with a textured coating to address the problem of coating peeling failure induced by the groove 119.

[0072] The surface of crankshaft 11 is treated with a textured coating coupling, or with either a coating or a texture, wherein the coating is in a multi-layer stacked form. The textured coating composite structure includes a substrate 01, a coating 02, and a texture 03. The coating 02 is disposed on the surface of the substrate 01, and the texture 03 is distributed on the surfaces of the substrate 01 and the coating 02.

[0073] The component substrate 01 is superimposed with multiple layers of coating 02. The coating 02 is superimposed with alternating hard and soft layers, from the base layer to the surface layer. First, a hard coating is applied, then a soft coating is applied, and the layers are repeatedly superimposed to ensure that the base layer is a hard coating and the surface layer is a soft coating.

[0074] The depth of texture 03 is 2 to 100 μm, preferably 7 μm, and the ratio of the total area of ​​the texture to the total area of ​​the lubrication distribution area ranges from 0.02 to 0.85, preferably 0.10.

[0075] The texture 03 and coating 02 are combined. The texture 03 can be processed on the substrate 01 first and then the coating 02 can be prepared. Alternatively, the coating 02 can be prepared first and then the texture 03 can be processed. Or, a portion of the coating 02 can be prepared first, and then the texture 03 can be processed before the remaining coating 02 is prepared. In this embodiment, the method of preparing the coating 02 first and then processing the texture 03 is adopted.

[0076] Coating 02 is a single layer structure, and it can also be prepared by simultaneously preparing a hard coating and a soft coating, such as by simultaneously treating nitriding and sulfurizing.

[0077] The textured coating coupling treatment can be applied to the friction pair surfaces of any compressor component.

[0078] The crankshaft surface coating 02 employs an alternating layering of hard and soft materials. The hard layers are wear-resistant and provide support for the soft layers, while the soft layers increase interlayer slippage and possess self-lubricating properties, reducing friction. This alternation of hard and soft materials gives the entire coating 02 structure multi-layer slippage characteristics, resulting in better wear-reducing performance. Simultaneously, the soft layers have a certain degree of elasticity, acting as a buffer against contact forces, and there is also a buffering effect between layers. Furthermore, the multi-layer coating 02 can prevent crack propagation, avoiding direct damage to the base layer in the event of failure.

[0079] When abnormal wear occurs, coating 02 comes into contact with other surfaces. The multi-layer coating 02 with alternating soft and hard surfaces transforms the rigid contact of the original pair into the elastic contact of the existing pair. The hard coating has strong wear resistance, and the coating with alternating soft and hard surfaces takes into account both wear reduction and wear resistance characteristics, which can effectively improve the problem of abnormal friction and wear on the end face.

[0080] The combination of coating 02 and texture 03 serves two purposes. First, texture 03 increases the surface contact area, enhancing the adhesion of coating 02. Second, due to the varying processability of different materials, single-layer or multi-layer coating 02 facilitates control over the depth of texture 03. For instance, if the base material or a particular coating layer is difficult to process, and a portion of the texture reaches a certain depth where the depth stops increasing or increases very slowly, then the remaining textures, which have not yet reached the corresponding depth, will increase in depth during further processing, while the original texture will remain relatively unchanged. This allows for control over the texture processing depth. The depth of texture 03 is a crucial parameter affecting the texture effect, but precise depth control during processing is challenging, often deviating from the design value. Coating 02 can be used to assist in controlling its processing depth.

[0081] When coating 02 is under stress, it undergoes elastic deformation, causing a change in the depth of texture 03 from h1 to h2. Since the texture depth affects its dynamic compressive characteristics, and consequently its load-bearing capacity, the elastic deformation of the coating allows the texture depth to automatically adjust according to the external load. By rationally configuring the materials and arrangement of each layer of the coating, coating 02 can automatically change its texture depth to a more suitable depth based on the load magnitude. For example, if the bottom of texture 03 has a coating with higher elasticity, while other areas have no coating or a coating with lower elasticity, under external stress, the bottom of the texture deforms and contracts more, while other areas contract less, resulting in an increased texture depth—that is, the texture depth increases with increasing load. Conversely, if the bottom of texture 03 has a coating with lower elasticity or no coating, while other areas have a coating with higher elasticity, under external stress, the bottom of the texture deforms and contracts less, while other areas contract more, resulting in a shallower texture depth—that is, the texture depth decreases with increasing load. The configuration of the texture and coating can be changed according to actual usage requirements.

[0082] Texture 03 can store lubricating oil and provide lubrication under low oil conditions. The significant hydrodynamic effect provided by Texture 03 enhances the oil film carrying capacity, ensures lubrication reliability, reduces friction, and avoids oil film rupture caused by changes in operating conditions or external disturbances during operation.

[0083] Texture 03 can be processed first, followed by coating 02. The advantage of doing so is that the texture can enhance the adhesion of the coating. Alternatively, some coatings 02 can be prepared first, followed by texture 03, and then the rest of the coatings 02 can be prepared. The advantage of doing so is that the texture enhances the adhesion of the coating, and because the texture and the coating on the bottom and the plane have different distributions, the coating can adjust the texture depth.

[0084] It will be readily understood by those skilled in the art that the above embodiments can be freely combined and superimposed without conflict.

[0085] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above description is merely a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A pump body assembly, characterized by, The pump body assembly comprises a crankshaft (11) and a roller, the crankshaft (11) comprises an eccentric part; The eccentric part is provided with a groove away from the axis of the crankshaft (11), the overall extension direction of the groove is axial and the groove penetrates the eccentric part; the groove opening is provided on the outer surface of the eccentric part, and the groove bottom is located on the inner surface of the eccentric part; in the cross section of the crankshaft (11), the depth direction of the groove contains a circumferential extension segment along the outer circumference of the eccentric part, and the groove penetrates the eccentric part along the axial direction, so that the outer part of the groove is deformed; The depth direction of the groove from the groove opening to the groove bottom is the same as the rotation direction of the crankshaft (11); When the eccentric part contacts the roller, the groove can be flexibly deformed to reduce the contact load and friction wear between the eccentric part and the roller.

2. The pump body assembly of claim 1, wherein, The crankshaft (11) is provided with a central oil hole (117), and the groove bottom communicates with the central oil hole (117).

3. The pump body assembly of claim 2, wherein, The crankshaft (11) is provided with a radial oil hole, which communicates the groove bottom and the central oil hole (117).

4. The pump body assembly of claim 1, wherein, The surface of the crankshaft (11) is provided with at least one of a coating (02) or a texture (03).

5. The pump body assembly of claim 4, wherein, The coating (02) comprises one or a combination of a hard coating and a soft coating, the hard coating is a DLC coating or a ceramic coating, and the soft coating is at least one of a PTFE coating, a PEEK coating, a MoS2 coating, a WS2 coating, a BaF2 coating, a CaF2 coating and a GLC coating.

6. The pump body assembly of claim 5, wherein, The hard coating is prepared by any one of coating, plating, carburizing, nitriding and surface heat treatment; or / and, the soft coating is prepared by any one of coating, plating, phosphating and sulfidation.

7. A pump body assembly according to claim 5 or 6, wherein, The coating (02) is a combined layer of hard coating and soft coating, and the outermost layer is the soft coating.

8. The pump body assembly of claim 4, wherein, The texture (03) comprises at least one of a groove type and a micropore type, the groove type is a grid shape, a straight line shape or a spiral shape; the micropore type is an elliptical hole, a triangular hole, a rhombic hole or a honeycomb hole.

9. The pump body assembly of claim 4, wherein, The texture (03) comprises at least one of a groove type and a micropore type, the groove type is a grid shape, a straight line shape or a spiral shape; the micropore type is a rectangular hole.

10. The pump body assembly of claim 8 or 9, wherein, The depth of the texture (03) is 2-100 μm, and the area ratio of the texture (03) is 0.02-0.

85.

11. A compressor characterized by, The pump body assembly comprises a crankshaft (11) and a roller, the crankshaft (11) comprises an eccentric part;

Images