Crankshaft structure, block assembly using the same, and air compressor

Abstract

Provided are a crankshaft structure, a box assembly using the crankshaft structure, and an air compressor. The crankshaft structure comprises a bearing, and a first shaft part and a second shaft part passing through the bearing from both sides. The difference from the prior art is that the first shaft part and the second shaft part are not pressed against the bearing respectively, but an assembly end of the first shaft part is formed to be in abutment with a connecting hole of the bearing, and then the second shaft part is assembled with the assembly end of the first shaft part. Thus, during assembly, the assembly interference between the shaft parts and the bearing on both sides does not need to be balanced, but the assembly is performed in an asymmetric manner, so as to reduce the equipment shaking caused by the difference in the interference on both sides of the bearing, and improve the equipment running stability. The cooling water channel formed in the box can solve the cooling problem of the overheating inside the box under the premise of ensuring the integration of the box assembly.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air compression equipment, in particular, to a split type crankshaft structure, a box containing the crankshaft structure, and an integrated water-cooled box and air compressor configured with the box. BACKGROUND

[0002] The statements in this section merely provide background information related to the present disclosure and can not constitute prior art.

[0003] An air compressor is a device that changes the pressure of gas in a cylinder by piston compression work. The high and low pressure piston cylinders contained in the common two-cylinder air compressor are often configured to reciprocate alternately, in which one side cylinder builds pressure and the other side releases its pressure. To adapt to the above process, the prior art provides various crankshaft structures, but the known crankshaft structures, due to the existence of process precision and press-fitting error, cause the imbalance of the interference amount between the machined parts, especially between the crankshaft and its bearing seat, and the crankshaft is prone to loose fit and damage after long-term operation.

[0004] On the other hand, the problem is that as the requirement for integration of air compression equipment is getting higher and higher, some existing integrated or split type crankshafts are integrated through box structure. However, while the prior art solves and emphasizes the integration problem, it ignores the heat generated by the operation of the crankshaft, which is gathered in the compact box structure, so that other integrated devices such as motors are always in a high working temperature state. To solve this problem, some known solutions are to configure a cooling pipeline near the location where the heat source occurs in the air compressor, but the bulky pipeline itself is contrary to the requirement of higher integration of the device. SUMMARY

[0005] Therefore, the present application provides a solution to at least one of the above problems.

[0006] To solve the above technical problems, the first aspect of the present application provides a crankshaft structure, which comprises a bearing, and a first shaft part and a second shaft part penetrating the bearing from both sides thereof. The difference from the prior art is that the first shaft part and the second shaft part are not pressed against the bearing respectively, but a fitting end of the first shaft part is formed to be in abutment with a connecting hole of the bearing, and then the second shaft part is fitted with the fitting end of the first shaft part. In this way, when fitting, it is not necessary to balance the fitting interference amount between the shaft parts on both sides and the bearing, but an asymmetric fitting is adopted to reduce the device shaking caused by the difference in interference amount on both sides of the bearing, and improve the running stability of the device.

[0007] To facilitate assembly and positioning, and to improve the tightness of the connection between the first shaft and the second shaft, at least two positioning pins are arranged between the assembly end of the first shaft and the mating end of the second shaft. The assembly end of the first shaft and the mating end of the second shaft respectively form holes, which can be spliced ​​together in the assembled state to form a channel through which the positioning pins can pass.

[0008] The unfolding direction of the first body on the first shaft is opposite to the extension direction of the second body on the second shaft, so that when the first body and the second body clamp the bearing from both sides, the contact positions of the two bodies with the bearing's two side surfaces are symmetrical, thereby maintaining the balance of the transmission assembly after rotation.

[0009] A second aspect of the present invention provides a housing assembly having a crankshaft structure according to the first aspect of the invention. Within the housing, an arc-shaped cooling chamber is formed along the inner wall of its cavity, the cooling chamber being divided into a plurality of communicating cooling channels by partitions. Coolant enters the cooling channels from an inlet at the bottom of the housing and flows along the arrangement path of the cooling channels from one bottom side of the housing to the other bottom side, then returns to the top of the housing at the inlet, thereby achieving sufficient heat exchange with the space within the housing.

[0010] The end cover of the enclosure includes a cover portion that fits onto the end of the enclosure and a control portion that is fitted onto the surface of the enclosure. A portion of the bottom of the control portion is inclined, so that in the assembled state, an open opening is formed between the control portion and the surface of the enclosure. This opening allows for clearance between the control portion and the surface of the enclosure when the end cover is fastened to the enclosure, facilitating the establishment of the fastening relationship between the control portion and the enclosure during assembly. Furthermore, the heat from the enclosure is not transferred to the control portion too quickly, thus affecting the operating temperature of components such as the junction box inside.

[0011] A third aspect of the present invention provides an air compressor comprising a crankshaft structure of the first aspect of the present invention and a housing assembly of the second aspect of the present invention. Attached Figure Description

[0012] Figure 1 For illustrative purposes, this diagram schematically illustrates an existing split crankshaft structure;

[0013] Figure 2 For illustrative purposes only, this diagram schematically shows the structure of the transmission structure in a loosely fitted state in a preferred embodiment of the present invention;

[0014] Figure 3 This is an exploded sectional view, showing... Figure 2 The cross-sectional view of the transmission structure in its assembled state is shown.

[0015] Figure 4 This is a sectional view, showing... Figure 2 The cross-sectional view of the transmission structure in its assembled state is shown.

[0016] Figure 5 is a sectional view showing Figure 2 the sectional structure of the first shaft portion;

[0017] Figure 6 is a sectional view showing Figure 2 the sectional structure of the second shaft portion;

[0018] Figure 7 is a schematic view showing Figure 5 the front view structure of the first shaft portion;

[0019] Figure 8 is a schematic view showing Figure 6 the front view structure of the second shaft portion;

[0020] Figure 9 is a schematic view showing the structure of the case assembly according to another aspect of the present application;

[0021] Figure 10 is a sectional view showing the sectional structure of the end opening of the case assembly on the piston side and the motor side;

[0022] Figure 11 is a sectional view showing Figure 9 the sectional structure of the case assembly;

[0023] Figure 12 is a sectional view showing the sectional structure of the cooling water passage including a plurality of partitions in another embodiment of the present application;

[0024] Figure 13 is a schematic view showing the structure of one end cover in the preferred embodiment of the present application;

[0025] Figure 14 is a side view showing Figure 13 the side view structure of the end cover;

[0026] Figure 15 is a sectional view showing Figure 13 the sectional structure of the end cover in the assembled state with the case. DETAILED DESCRIPTION

[0027] One of the existing split crankshafts is, for example, a split crankshaft disclosed in the Utility Model Patent No. CN217029618U, which is centered on the bearing mounting seat to form an opposed structure of two-cylinder crankshafts. Figure 1For the schematic diagram, the prior structure is shown, such as the bearing seat of the high-pressure cylinder crankshaft and the low-pressure cylinder crankshaft. Considering the manufacturing errors that may exist in the crankshaft and the seat body workpiece, as well as the possible deviation of the pressing force in the pressing process, it may cause the interference amount on one side to be larger than the other side. If the crankshaft with asymmetric interference amount on both sides is used to drive the cylinder body to move, the crankshaft with relatively small interference amount will not meet the assembly requirements due to the interference amount, and the long-term execution result is that the frequent shaking of the crankshaft during the rotating movement eventually leads to the risk of loose assembly or even falling of the components in the crankshaft.

[0028] To solve the problems faced by the existing split crankshaft, the preferred embodiment of the present application first realizes that the workpiece error caused by the manufacturing process cannot be avoided, therefore, if the interference amount is required to be balanced to improve the execution stability of the split crankshaft, the interference fit relationship between the crankshaft and the bearing seat should be improved to minimize or eliminate the influence caused by the above error.

[0029] Another aspect to consider is that the improved structure may still face the problem of difficulty in dissipating internal heat sources to meet the requirement of equipment integration. For example, in some existing improved structures, a double support combined with an independent motor is used in the air compressor. These schemes are to cancel the coupling structure in the earlier scheme, and the crank of the crankcase is connected to the inner circumference of the motor through an independent connecting piece. For example, a kind of air compressor transmission structure is described in the Chinese invention patent with the authorization announcement number CN118855837B, one side of the crankshaft is connected to the main shaft of the motor, compared with the earlier technology, the connecting piece such as coupling is omitted, but due to the associated structure of double support combination, higher requirements are put forward for the concentric machining precision between the components of the transmission structure and the assembly precision. And in this scheme, the driving force of the driving motor is transmitted from the motor side to the piston side through the crank of the transmission structure, which has at least two problems:

[0030] 1) The motor is independently set, in order to adapt to the extension of the motor and the transmission structure in the length direction of the box, at the same time, in order to realize the technical effect of detachable motor side, more space is reserved between the transmission structure and the motor in the prior application scheme. Therefore, relatively speaking, the integration degree of the prior scheme has not been maximized, and there is still room for improvement;

[0031] 2) However, another aspect to consider is that the space left between the motor and the transmission structure forms a space for the motor and the transmission structure. Due to the lack of necessary internal heat source cooling means, in order to avoid the accumulation and transmission of heat between the motor and the piston cylinder on both sides, the prior scheme leaves space between them to improve the problem that heat is difficult to dissipate.

[0032] In general, based on the existing technical knowledge, higher integration and internal heat source heat dissipation are contradictory, that is, higher internal integration will inevitably lead to adverse effects on cooling, and better cooling effect requires space between components. In fact, the technical purpose of the prior application of the example is to configure the motor side to be detachable, which is partly related to the detachable relationship of the transmission structure to facilitate maintenance, and partly to expose the motor side when overheating to alleviate the problem of insufficient cooling means to some extent.

[0033] The preferred embodiment of the present application solves the above problems. At least from the perspective of integration, the motor side box and the piston pump head side box are further integrated, which can shorten the absolute distance between the transmission structure opposite crankshafts, and further "compress" the transmission structure to improve the integration. On the other hand, the bearing seat is set as an integrated structure spliced by multiple concentric components, and during the interference pressing process, the two crankshafts and the bearing seat realize the three combined sleeve setting relationship to achieve the technical purpose of balancing the interference force. Furthermore, considering the cooling problem after higher integration, an axial communication cooling water channel is configured in the integrated box structure from the piston cylinder side to the motor side and back to the piston cylinder side to integrate the motor cooling and air compressor pump head water cooling.

[0034] Embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art can recognize that the described embodiments can be modified in various ways without departing from the spirit and scope of the present application. Therefore, the drawings and description are essentially illustrative, not for limiting the scope of protection of the claims. In addition, in this specification, the drawings are not drawn to scale, and the same reference numerals represent the same parts.

[0035] It should be noted that the "first" and "second" expressions used in the embodiments of the present application are used to distinguish two same name different entities or different parameters. It can be seen that "first" and "second" are only for the convenience of description, and should not be understood as a limitation of the embodiments of the application. The subsequent embodiments will not be described one by one.

[0036] According to the technical idea of the present application, the first aspect is to improve the existing double support transmission structure. Looking back Figure 1 In the existing structure as shown in Figure 1 The installation process of the shaft body and the fixed part is: along the hole center line direction of the opening, the shaft necks of the two shaft bodies are pressed and fitted with the opening respectively, and the pressing directions of the two are opposite. After forming, the two shaft necks and the opening form the same interference fit, and since the profiles of the two ends coincide with each other, the end parts of the two shaft necks are in close contact after the shaft sleeve is pressed tightly. In order to balance the accuracy of the transmission structure after execution, in the preferred scheme, it is required that the interference amount of the shaft necks of the two sides extending into the opening is the same, so thatFigure 1 In the direction shown, the two journals in this transmission structure are symmetrically configured about the center.

[0037] In a first aspect of a preferred embodiment of the present invention, an asymmetrical structure is provided between the aforementioned two components. Here, "asymmetrical" refers both to the asymmetrical structure of the crankshafts at both ends of the bearing and to the fact that the crankshafts at both ends are connected to the bearing in an asymmetrical and non-identical manner, thereby reducing the requirement for equal interference fits on both sides of the transmission structure during assembly. See also... Figure 2 , Figure 2 For illustrative purposes, this diagram schematically illustrates the structure of the transmission structure under loose configuration in a preferred embodiment of the present invention, according to... Figure 2 The direction presented is defined by the transmission direction of the transmission structure (from the motor side to the piston side), which gives rise to a first direction ( Figure 2 If, in a direction from right to left, a first shaft portion 100 and a second shaft portion 200 are defined in the first direction, then the transmission structure is a press-shaped structure extending along the first direction, wherein the first shaft portion 100 and the second shaft portion 200 are assembled in opposite directions from both sides of the central support bearing 300. See also... Figure 3 and Figure 4 , Figure 3 This is a sectional exploded view. Figure 4 The sectional view shows the following: Figure 2 The cross-sectional views of the transmission structure in its assembled and combined states, as shown, combine... Figure 2 It can be seen that it is different from Figure 1 In the preferred embodiment of the present invention, the existing structure shown does not have the first shaft portion 100 and the second shaft portion 200, which are respectively the high and low pressure crankshafts, press-fitted to the support bearing 300 from both sides. Instead, the first shaft portion 100 on one side is provided with a hole for interference fit with the second shaft portion 200 on the other side. Then, the assembly process is to first insert the assembly end of the first shaft portion 100 on one side into the connecting hole on the support bearing 300, and then insert the assembly end of the second shaft portion 200 on the other side into the connecting portion on the first shaft portion 100. The three parts are then combined to form the structure.

[0038] Combination Figure 2 and Figure 4 See Figure 3 The support bearing 300 is a hollow annular part, which is tightly fitted by the cylinder liner 400 on its outer side. The hollow part is the aforementioned connecting hole 301. The connecting hole 301 defines an annular space, and the mating parts on the first shaft part 100 and the second shaft part 200 on both sides are mated with the support bearing 300 in this annular space.

[0039] The connection between the first shaft portion 100 and the second shaft portion 200 includes two parts. First, as mentioned earlier, the second shaft portion 200 includes a mating end for extending into the first shaft portion 100. The mating end extends into the hole of the first shaft portion 100 so that the first and second shaft portions fit together. Second, after the first shaft portion 100 and the second shaft portion 200 are connected, they are also fixed together by inserting a locating pin. Let's first discuss the first shaft portion 100, see... Figure 5 , Figure 5 This is a sectional view, showing... Figure 2 Cross-sectional view of the first axial portion 100. According to... Figure 5 In the display direction, the first shaft portion 100 includes a first body 101, with an assembly end having a hole formed on each side of the first body 101 in the first direction, and a first crankshaft end 102 that performs a rotational action and is connected to a crank, and the surfaces of the assembly end and the first crankshaft end 102 face the two sides of the first direction respectively.

[0040] The assembly end can also be roughly understood as a protrusion extending further in the opposite direction to the first direction from the surface of the first body 101, and the surface of the protrusion is recessed towards the side where the first body 101 is located to form a first hole 103. The structure of the first crankshaft end 102 can be understood as follows: firstly, one end of the first body 101 protrudes in the first direction to form another protrusion, which is used to connect with the crankshaft of the piston cylinder, and its surface is recessed to form a second hole 104. The first hole 103 serves as a mounting hole for the mating end of the second shaft 200, and the mating end of the second shaft 200 mates with the first hole 103. The end formed by the second hole 104 is used to mate with the drive shaft (e.g., the crank of the piston cylinder) on the other side, which will be explained later. It should also be noted that the protrusion of the assembly end of the first shaft 100 extends further along both sides in its radial direction, thereby extending in the radial direction of the first shaft 100 (i.e., Figure 5 A first widening surface 105, roughly fan-shaped, is formed on the vertical direction. When the whole assembly is formed, the function of the first widening surface 105 is to match the second widening surface on the second shaft 200 so that the two sides of the whole formed by the fitting of the support bearing 300 and the cylinder liner 400 can respectively partially fit with the two widening surfaces to maintain the rotational balance of the transmission assembly.

[0041] Figure 6 This is a sectional view, showing... Figure 2The cross-sectional structure of the second shaft portion 200 is shown in the figure. The second shaft portion 200 includes a second body 201, a protrusion extending from one side of the second body 201 in a first direction (which is also the aforementioned mating end 202 for fitting with the first hole 103 of the first shaft portion 100), and a second crankshaft end 203 extending from the other side of the second body 201 toward the motor side (opposite to the first direction). The second crankshaft end 203 is used for connecting to the crank of another piston cylinder, and its end forms a third hole 204 for mating with the drive shaft of the motor. Similar to the first shaft portion 100, the second body 201 also has a protrusion in the radial direction (i.e.,...) Figure 6 Extending further to both sides in the vertical direction of the protrusion, a second widening surface 205 is formed. The second widening surface 205 is roughly rectangular and is located on both sides in the radial direction of the protrusion, forming an arc segment and the edge surface of the arc segment, respectively. In the assembled state, the unfolding direction of the first widening surface 105 and the second widening surface 205 is opposite to that of the central axis of the transmission assembly. This reverse unfolding should be understood as... Figure 2 The directions shown, namely the central axes of the first widening surface 105 and the second widening surface 205 along their length, are both perpendicular to the central axis of the entire transmission assembly. The first widening surface 105 extends downwards perpendicular to the central axis of the entire transmission assembly, and the second widening surface 205 extends upwards perpendicular to the central axis of the entire transmission assembly. Furthermore, the surfaces of the first and second widening surfaces are parallel to each other. (Looking back...) Figure 2 In the assembled state, the support bearing 300 and cylinder liner 400 are respectively fitted to the first widening surface 105 and the second widening surface 205 on both sides in the first direction. This allows the support bearing 300 and cylinder liner 400 at the center of the assembly to be clamped together by opposing support forces in two directions. While ensuring a tight assembly, this reduces the extension width of the first body 101 and the second body 201, thereby lowering the overall counterweight of the transmission assembly while maintaining rotational balance. This completes the first aspect of the mutual assembly of the first shaft portion 100 and the second shaft portion 200.

[0042] A second aspect of assembling the first shaft portion 100 and the second shaft portion 200 is that it also includes a locating pin 500 for achieving a fastening connection between the two. Figure 7 For illustration purposes, it shows Figure 5 The front view of the first axis section is shown. Figure 8 For illustration purposes, it shows Figure 6 The main view of the second axis section is shown. (See also...) Figure 7 The first hole 103 of the first shaft portion 100 also includes two fourth holes 106.

[0043] , fourth hole part 106 is a through hole structure connecting the assembly end of first shaft part 100 and first crank end 102, at the same time, the two openings of fourth hole part 106 in its extension direction are both blind hole shaped opening part, and connecting nut 501 threaded by positioning pin 500 is inserted into positioning pin from one side opening. Referring to Figure 8 , fifth hole part 206 corresponding to fourth hole part 106 is also formed in the butt joint end 202 of second shaft part 200, thus referring back to Figure 3 , in assembly state, part of positioning pin 500 is located in first hole part 103 of first shaft part 100 and further extends into fourth hole part 106, another part of positioning pin 500 is located in fourth hole part 106 of second shaft part 200, thus it should be understood that when first shaft part 100 and second shaft part 200 are butt jointed, butt joint end of second shaft part 200 extends into first hole part 103 of first shaft part 100, positioning pin 500 is arranged in the space formed by fourth hole part 106 and fifth hole part 206 when connecting nut 501 is inserted from the surface of first body 101 of first shaft part 100, extends from the blind hole shaped opening of fourth hole part 106 at this side and is screwed into fifth hole part 206, thus making first shaft part 100 and second shaft part 200 fastened and connected. It should be understood that the one-to-one corresponding configuration of fourth hole part 106 and fifth hole part 206 can play a positioning role, this "positioning" refers to the correspondence between fourth hole part 106 and the opening of second hole part 104 on one hand, so that connecting nut 501 can be smoothly inserted and screwed and assembled, on the other hand, through positioning assembly, the orientation of first widened surface 105 of first shaft part 100 and the orientation of second widened surface 205 of second shaft part 200 are preset, that is, perpendicular to the direction of the overall axis of transmission assembly, and also keep opposite orientation in the radial direction of the assembly. Correspondingly, in assembly state, the orientation of third hole part 204 for connecting with one side of motor and the orientation of second hole part 104 for connecting with rear stage drive shaft are also opposite, and the central axis of second hole part 104 is perpendicular to the extension direction of first body 101, and the central axis of third hole part 204 is perpendicular to the extension direction of second body 201. Although it is not shown in the drawings of the present application, it should be understood that in assembly state, the central axis of motor drive shaft, the central axis of transmission assembly and the central axis of rear stage drive shaft keep parallel and coplanar, so that when the motor is driven, motor drive shaft and rear stage drive shaft rotate asynchronously.

[0044] Compared with the prior art, the high-low pressure crankshaft is pressed from both sides with the bearing (for example, Chinese Patent No. CN217029618U), the transmission structure mentioned in the preferred embodiment of the present application is first inserted into the connecting hole 301 of the supporting bearing 300 when the assembly is in the assembly state, and the first shaft part 100 is tightly fitted between the supporting bearings 300 to form an interference. In the pressed state, the first body 101 on the first shaft part 100 is in contact with the annular surface of the supporting bearing 300. Then, the butt joint end of the second shaft part 200 is inserted into the first hole part 103 of the first shaft part 100 to form a plug-in connection, and the second body 201 on the second shaft part 200 is in contact with the other side of the annular surface of the supporting bearing 300. In this way, the first shaft part 100 and the second shaft part 200 press the supporting bearing from both sides to form a whole transmission structure. Therefore, in the preferred embodiment of the present application, the assembly relationship between the first shaft part 100 and the supporting bearing 300, and the assembly relationship between the second shaft part 200 and the first shaft part 100 are all plug-in connections, which are more stable and compact, and the stress strength of the whole transmission assembly is improved.

[0045] In the existing scheme, the transmission assembly is placed in the box body of the air compressor as a transmission part connecting the piston side and the motor side. In some existing schemes, the box bodies of the piston side and the motor side are independent and combined into a whole in a splicing form. In this scheme, due to the structural difference between the piston side and the motor side, cooling means and cooling devices (usually cooling pipes) need to be arranged on the piston side and the motor side respectively to meet the cooling demand. On the one hand, the additional cooling pipes cause poor integration of the air compressor, and there is a possibility of cooling liquid leakage. On the other hand, part of the transmission assembly is located in the area between the piston side and the motor side, which cannot be covered by the cooling means, causing local overheating of the transmission assembly. Due to excessive accumulation of heat in the local position, the overall temperature in the box space is always high, and the cooling efficiency and effect of the cooling means are poor.

[0046] If the box bodies of the piston side and the motor side are designed as an integrated structure to improve the integration of the air compressor, considering the arrangement direction of the motor and the arrangement direction of the piston cylinder, which are often perpendicular to each other, the space in the box body is always limited in the scheme including the transmission assembly. The additional cooling devices cannot be deployed in the limited space, and even if certain cooling means are arranged in the limited box space, these means will affect the overall weight of the transmission assembly, and the crowded arrangement space in the local area is not conducive to improving the cooling effect in the box body.

[0047] To solve the above problems, the preferred embodiment of the present application realizes that, although the arrangement direction of the piston cylinder cannot be changed, the transmission assembly and the motor can be arranged in the same direction and located in an integrated box, and an internal pipeline for the flow of the cooling liquid is formed inside the integrated box. In order to prolong the flow path of the cooling liquid in the box and make it better to play its cooling role, the extension of the internal pipeline should cover as much as possible the internal space of the box.

[0048] In other possible embodiments of the present application, the internal pipeline can be arranged in a spiral distribution in the radial direction of the box. The spiral distribution specifically refers to that the internal pipeline extends in the length direction of the box from the bottom to the top of the side of the box, and then extends from the top to the bottom, until it extends from one end to the other end of the length direction of the box. In these embodiments, the flow direction of the liquid is from the bottom to the top of the box and then back to the bottom, and so on, so that the internal pipeline has a longer extension path, and the cooling liquid can better play its cooling role. However, even if this box with an internal spiral cooling pipeline is not considered, the complexity of the manufacturing process cannot be further reduced to meet the distribution of the spiral internal pipeline on the side of the box, and because there are multiple inflection points in the spiral pipeline, the flow of the cooling liquid in the spiral pipeline is not smooth, so the cooling liquid can stay in the pipeline for a longer time, but the cooling efficiency is not better.

[0049] In the preferred embodiment of the present application, the box is as shown in Figure 9 The curved line with an arrow in the figure shows the extension path of the cooling pipeline inside the box 600, which is also the flow path of the cooling liquid inside the box 600. As shown in the figure, the cooling liquid enters from the water inlet 601 at the bottom of the end face of one side of the box 600, and is discharged along the internal pipeline to the bottom of the other side of the box 600, then turns from bottom to top and returns to the top position of the side of the box close to the water inlet 601 of the box, and finally is discharged through the top water outlet 602 to the next level equipment. If the two sides of the box are divided into the piston side and the motor side, the flow of the cooling liquid is from the piston side to the motor side and then back to the piston side.

[0050] Continuing to refer to Figure 9In the preferred embodiment, two crankshaft holes are formed on the top surface of the piston side of the box 600, and the two crankshaft holes correspond to the first shaft part 100 and the second shaft part 200 respectively. For the purpose of illustration, the crankshaft hole corresponding to the first shaft part 100 is defined as the first crankshaft hole 603, and the crankshaft hole corresponding to the second shaft part 200 is defined as the second crankshaft hole 604. In the assembled state, the first crankshaft end 102 of the first shaft part 100 is fitted into the crank sleeve of the high-pressure cylinder, and the second crankshaft end 203 of the second shaft part 200 is fitted into the crank sleeve of the low-pressure cylinder. In different preferred embodiments, the correspondence between the crankshaft end and the high / low-pressure cylinder crank can obviously be interchanged.

[0051] Continuing to refer to Figure 9 , the end surfaces of the piston side and the motor side of the box 600 are respectively formed with openings, and the two openings will be closed after assembly and molding. The end opening of the piston side will be covered by the first end cover (front cover) of the box, and the end opening of the motor side will be covered by the second end cover (rear cover) of the box. Referring to Figure 10 , Figure 10 (a) and Figure 10 (b) respectively show the partial cross-sectional structure of the end opening of the piston side and the end opening of the motor side. On both sides along the radial direction of the opening, an arc-shaped water channel port is formed around the opening. Referring to Figure 11 the cross-sectional view angle shown in Figure 9 , it can be seen that the water channel ports at the end openings of the piston side and the motor side are connected to form two arc-shaped cooling water channels extending from the piston side to the motor side in the box 600. A partition plate 605 is arranged in the cooling water channel. The partition plate 605 has the function of separating the arc-shaped cooling water channel into two parts, which are defined as the first water channel 606 and the second water channel 607 for the purpose of illustration. The forming method of the first water channel 606 and the second water channel 607 is as follows: first, an integrated water channel is formed through the box by stretching, and then the partition plate 605 is arranged in the integrated water channel. The partition plate 605 is a long straight piece extending along the length direction of the box 600. The two end portions of the partition plate 605 are both formed at a certain distance from the two end surfaces of the box 600, but the distances from the two end surfaces are different. Among them, the partition plate 605 is kept at a relatively small distance from the end surface of the piston side in order to facilitate the end sealing by friction stir welding with a sealing block, and then the water inlet 601 can be processed on the surface of the friction-welded and sealed end surface. Therefore, the distance between the partition plate 605 and the end surface of the box on this side is relatively small. The partition plate 605 is kept at a certain distance from the end surface of the motor side in order to make the first water channel 606 and the second water channel 607 communicate with each other. In this way, the cooling water can flow from the first water channel 606 to the second water channel 607 at this position to complete the aforementioned turning-back process. Therefore, in order to ensure the flow of the cooling liquid, a sufficient space needs to be reserved between the partition plate 605 and the end surface of the box on this side.

[0052] Of course, in order to increase the flow distance of the cooling liquid in the box, and make it better to play its cooling role, Figure 9 The cooling water channel shown can also contain a plurality of partitions 605, which divide the cooling water channel into more interconnected parts. Such an embodiment is as shown in Figure 12 The structure, referring back to the part of the spiral water channel embodiment, the number of water channels and partitions, needs to be balanced between the cooling efficiency of the cooling liquid and the overall integration of the device, so as to ensure the cooling effect of the box on the internal components.

[0053] In addition to the box and the internal components of the box, in the prior art, the control unit for controlling the rotation of the motor is often externally mounted on the box. Considering the dynamic balance of the whole machine, the control unit is usually configured in a junction box and located on the other side of the piston cylinder relative to the whole machine. Based on the integrated box structure of the piston side and the motor side, the preferred embodiment of the present application further realizes that configuring the control unit at the rear of the box can better balance the dynamic balance effect of the whole machine.

[0054] Referring back to the foregoing, the end openings on both sides of the box 600 need to be sealed, and the end opening on the motor side is sealed by a rear cover structure. Therefore, the preferred embodiment of the present application integrates the rear cover with the junction box containing the control unit to form an integrated structure, further improving the overall integration of the device. For example, the rear cover structure is configured to include a cover body part that covers the end opening of the box, and a control part that closely fits the surface of the box, that is, the cover body part and the control part form a generally "L" shaped structure. However, in this structure, the specifications of the part of the structure that transitions from the cover body part to the control part need to be strictly controlled. If this part is configured too tightly, the assembly of the transition part and the box will become difficult, and the transition part is prone to cracking during long-term operation of the device due to factors such as device vibration and thermal expansion and contraction of the device itself. If the transition part structure is loosely fitted with the box, it is not conducive to the sealing of the end face of the motor side of the box, and the device may produce difficult-to-suppress noise during operation.

[0055] In view of the above two aspects, the preferred embodiment of the present application provides an end cover structure as shown in Figure 13 and Figure 14 As shown in Figure 13 and Figure 14The end cap 700 consists of two parts: a cover portion 701 for fitting with the motor side of the housing 600, and a control portion 702 for carrying a junction box that controls the rotation of the motor. The cover portion 701 extends outward from the base 7011 toward the motor shaft. In a first direction, or in the direction in which the end cap 700 engages with the housing 600, one side of the cover portion 701 forms a closed bottom cover, and the other side forms a cavity 7012 that accommodates the motor shaft. Thus, when the end cap 700 engages with the housing 600, the electrode shaft can at least partially extend into the cavity 7012. (Further details omitted) Figure 13 The body of the control unit 702 extends further in the first direction, thereby forming an angle between the bottom of the body of the control unit 702 and the cover portion 701 in the first direction. At the same time, the bottom of the body of the control unit 702 is partially inclined, that is, an acute angle is formed between the bottom 7021 of the body of the control unit 702 and the cover portion 701. Figure 14 (At the mid-angle Y), it should be understood that this corner position, that is, the part where the cover transitions to the control section, creates an opening between the bottom of the control section and the surface of the enclosure. This opening allows for clearance between the control section and the enclosure surface when the end cover 700 and the enclosure 600 are fastened together. This facilitates the establishment of the fastening relationship during assembly, and prevents heat from the enclosure from being transferred too quickly to the control section, thus affecting the operating temperature of internal components such as the junction box. The assembly state is as follows: Figure 15 The state shown, Figure 15 As shown in the side sectional view, in the assembled state, the control part 702 of the end cover 700 and the top surface of the housing 600 form an open structure.

[0056] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A crankshaft structure, which is a transmission device for transmitting driving force of a drive device, wherein the transmission direction of the crankshaft structure is defined as a first direction, characterized in that, The crankshaft structure comprises a bearing, a hollow portion of the bearing forming a connecting hole bidirectionally extendable in a first direction; a first shaft portion, the first shaft portion comprising a first body, one side of the first body being an assembly end extendable into the connecting hole, the other side of the first body being a first shaft end performing a rotating action, the assembly end comprising a first hole portion, the assembly end extending into the connecting hole in an assembled state so that the first shaft portion is pressed against the bearing; a second shaft portion, the second shaft portion comprising a second body, one side of the second body being an abutting end extendable into the first hole portion, the other side of the second body being a second shaft end performing a rotating action, the abutting end extending into the assembly end in an assembled state so that the asymmetric first shaft portion and the second shaft portion are combined with the bearing to form a structure, wherein a bottom of the first hole portion forms a through hole extending to the side of the first shaft end, the through hole forms openings in the form of blind holes on both sides of the surface of the first body, the abutting end of the second shaft portion forms at least one counterbore corresponding to the through hole, the through hole and the counterbore are communicated to form a positioning groove for a connecting member to pass through in the assembled state, and the connecting member connects and fastens the first shaft portion and the second shaft portion.

2. The crankshaft structure according to claim 1, characterized by The end of the first shaft end is opposite to the opening of the first hole portion on the assembly end.

3. The crankshaft structure according to claim 1, characterized by The surface of the first body forms a fan surface, the surface of the second body forms a rectangular surface, the development direction of the fan surface of the first body is opposite to the extension direction of the rectangular surface of the second body, so that the positions of the first body and the second body in contact with the surfaces of the bearing on both sides are centrally symmetric about the axis of the crankshaft structure in the first direction.

4. A box assembly comprising a piston side and a motor side, characterized in that The box assembly further comprises the crankshaft structure of any one of claims 1 to 3, which transmits the driving force of the motor side to the piston cylinder on the piston side.

5. The box assembly of claim 4, wherein, The side surface of the box assembly forms two crankshaft holes, comprising: a first crankshaft hole corresponding to the first shaft portion of the first shaft portion; a second crankshaft hole corresponding to the second shaft portion of the second shaft portion, wherein the high-pressure cylinder crank and the low-pressure cylinder crank pass through the first crankshaft hole and the second crankshaft hole and are connected with the first shaft portion or the second shaft portion.

6. The box assembly of claim 4, wherein, The box comprises a body and a receiving cavity formed in the body for accommodating the crankshaft structure, and a cooling cavity formed in the body and arranged around the receiving cavity.

7. The box assembly of claim 6, wherein, The cooling cavity is arc-shaped and is arranged partially around the receiving cavity, at least one partition is formed in the cooling cavity, the partition extends along the arrangement direction of the cooling cavity and separates the cooling cavity into a plurality of communicating cooling water channels, wherein the two ends of the partition are spaced apart from the end faces of the box by different distances.

8. The box assembly of any one of claims 4 to 7, wherein, Further comprising an end cover, the end cover is in the form of "L", comprising a cover body portion covering the end of the box and a control portion assembled with the surface of the box, wherein the bottom of the control portion is at least partially inclined to form an open gap between the control portion and the surface of the box.

9. An air compressor characterized by comprising: The box assembly comprises the crankshaft structure or the box assembly of any one of claims 1 to 8.

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