CN111878351A

CN111878351A - Two-stage compressed air compressor

Info

Publication number: CN111878351A
Application number: CN202010809972.0A
Authority: CN
Inventors: 朱彬; 李传武; 钟周乐; 周胜博
Original assignee: Ruili Group Ruian Auto Parts Co Ltd
Current assignee: Zhejiang Ruili air compressor equipment Co.,Ltd.
Priority date: 2020-08-13
Filing date: 2020-08-13
Publication date: 2020-11-03

Abstract

The invention provides a two-stage compressed air compressor, comprising: the high-pressure piston and the low-pressure piston are respectively connected with the eccentric connecting rod through piston pins; the crankshaft is respectively connected with the motor spindle and the eccentric connecting rod, and defines an area between the valve plate and a cylinder cover of the air compressor as a low-pressure cavity and a high-pressure cavity, wherein when the low-pressure piston moves from a lower dead point to an upper dead point and simultaneously the high-pressure piston moves from the upper dead point to the lower dead point, gas in the low-pressure piston cylinder body is compressed and then discharged into the low-pressure cavity from the low-pressure piston cylinder body and then enters the high-pressure piston cylinder body; when the low-pressure piston moves from the upper dead point to the lower dead point and the high-pressure piston moves from the lower dead point to the upper dead point, gas in the cylinder body of the high-pressure piston enters the cylinder body of the high-pressure piston and is discharged to the high-pressure cavity, so that gas in the piston cylinder is compressed for the second time, the exhaust pressure is improved, the exhaust temperature is reduced, the loads of all components of the air compressor are reduced, and the service life of the whole air compressor is prolonged.

Description

Two-stage compressed air compressor

Technical Field

The invention belongs to the technical field of air compressors for vehicles, and particularly relates to a two-stage compressed air compressor.

Background

The air compressor used in the automobile is mainly used as an air source for supplying air to equipment including automobile braking, suspension, door opening and other auxiliary air-using devices, the piston type air compressor is a common automobile electric air compressor, fig. 1 is a sectional view showing a sectional structure in a cylinder of a piston type air compressor of a prior art, referring to fig. 1, the piston air compressor includes two rows of pistons, defined as a first piston 10a and a second piston 20a, the figure shows the distance D between the piston axes of the first piston 10a and the second piston 20a, it is expected that when the air compressor operates the two pistons to reciprocate up and down, inertia force is generated between the crank-link mechanisms of the two pistons due to mass unbalance, and in addition, the distance between the two pistons is larger, so that the inertia moment generated together is also larger.

In the existing air compressor, two cylinders of air are directly discharged after primary compression, the air compression efficiency is low, the energy loss is large, and in the compression process, the friction of the piston in alternate reciprocating motion and the heat generated by compressed air heat all the parts, so that the exhaust temperature is too high, the service life of the components such as the bearing is finally influenced, and the operation stability of the whole air compressor cannot be guaranteed.

In view of this, should improve prior art to solve prior art down other insufficient compression of air compressor machine, exhaust temperature height, the short technical problem of subassembly life.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a two-stage compressed air compressor which can fully compress gas in cylinders of a high-pressure piston and a low-pressure piston, thereby saving energy consumption, reducing the operation temperature and the exhaust temperature of components and ensuring the service life of each component and the operation stability of the whole compressor.

In order to solve the technical problems, the invention provides a two-stage compressed air compressor, wherein two cylinder pistons in a box body of the air compressor are respectively a high-pressure piston and a low-pressure piston, and the tops of cylinder bodies of the high-pressure piston and the low-pressure piston are provided with a valve plate, and the two-stage compressed air compressor further comprises: the high-pressure piston and the low-pressure piston are respectively connected with the eccentric connecting rod through piston pins; the crankshaft is respectively connected with a motor main shaft and the eccentric connecting rod, the motor main shaft rotationally drives the crankshaft to rotate, the valve plate is fixed through a cylinder cover, and an area between the valve plate and the cylinder cover is defined as an airflow cavity, wherein when the low-pressure piston moves from a lower dead point to an upper dead point and simultaneously the high-pressure piston moves from the upper dead point to the lower dead point, gas in the low-pressure piston cylinder body is compressed in a first stage and enters the airflow cavity from the low-pressure piston cylinder body and then enters the high-pressure piston cylinder body; when the low-pressure piston moves from the top dead center to the bottom dead center and the high-pressure piston moves from the bottom dead center to the top dead center, the gas in the high-pressure piston cylinder body is compressed for two stages and is discharged by the high-pressure piston cylinder body.

Preferably, the low pressure piston comprises thereon: the first air inlet valve plate can be connected with the end part of the cylinder body of the low-pressure piston in a covering manner, and the bottom of the cylinder body of the low-pressure piston is sealed by the first air inlet valve plate in a non-pressure-bearing state; the first exhaust valve plate can be connected with the valve plate in a covering mode, and the top of the low-pressure piston is sealed through the first exhaust valve plate in a non-pressure-bearing state; the second air inlet valve plate can be connected with the high-pressure piston in a covering mode and can seal the space between the high-pressure piston and the valve plate in an unpressurized state, and the second air outlet valve plate can be connected with the valve plate in a covering mode and can seal the space between the high-pressure piston and the valve in an unpressurized state.

Further preferably, the first exhaust valve plate and the second exhaust valve plate are both provided with a stroke limiting plate, one end of the stroke limiting plate is fixed with the valve plate and extends obliquely towards the upper part of the exhaust valve, and then the first exhaust valve or the second exhaust valve is turned over towards the direction of the airflow cavity and limited by the stroke limiting plates above the first exhaust valve or the second exhaust valve.

Still further preferably, the high pressure piston and the low pressure piston are both provided with self-lubricating piston rings and guide rings.

Still further preferably, the motor spindle is fixed to the housing by a tension sleeve and a bolt, and the high-pressure piston and the low-pressure piston are mounted to the crankshaft, and the motor spindle and the outer side of the motor spindle are respectively provided with a maintenance-free bearing, wherein a dust-proof oil seal is disposed outside the maintenance-free bearing.

Preferably, the cylinder cover is provided with an exhaust port, wherein the gas compressed in the high-pressure piston in the second stage enters the high-pressure cavity from the second exhaust valve and is then exhausted through the exhaust port on the cylinder cover.

Still preferably, a plurality of silencing holes are formed in the box body, wherein gas enters the box body through the plurality of silencing holes and then enters the low-pressure piston cylinder through the first air inlet valve plate.

Compared with the prior art, the invention has the following beneficial technical effects due to the adoption of the technical scheme:

1. the pistons are arranged in parallel and oppositely and distributed on two sides of the axis direction of the crankshaft, so that the axial distance of the pistons is zero, and the first-order reciprocating inertia moment and the rotating inertia moment are further balanced on the basis of balancing the first-order reciprocating inertia force, the rotating inertia force and the second-order reciprocating inertia moment in the alternate reciprocating constant-speed motion of the two-cylinder piston;

2. furthermore, the distance between the two cylinder pistons is reduced, so that the problem that mutual superposition of first-order reciprocating inertia moment is difficult to balance and eliminate in the prior art by adding a balance weight on a crank is solved;

3. the first-order reciprocating inertia moment and the rotating inertia moment are balanced, so that the vibration problem in the whole operation process of the mechanism is greatly relieved, the stability of equipment operation is ensured, and the service life of the whole mechanism is ensured;

4. the first connecting rod and the second connecting rod of the two-cylinder piston can adopt different shapes or material proportions to realize the same mass and gravity center, for example, the first connecting rod is arranged to be forked from one end to one side to form a V-shaped connecting piece with two big ends, and the two big ends are butted with corresponding cranks of a crankshaft;

5. the piston connecting rod is connected with two offset-arranged cylinder pistons, and the offset two cylinder pistons are also made into the same mass by adopting different material densities, so that the first-order reciprocating inertia force and the rotating inertia force are balanced, and the vibration amplitude of the whole machine in the running state is reduced;

6. the two pistons which are oppositely arranged or arranged in an offset way can reduce the volume of the piston cylinder, so that the structure of the whole machine is more compact, the whole machine arrangement is convenient, the specification of the whole machine is reduced, and the service life of the whole machine is prolonged;

7. a lubricating oil passage which is vertical to the extending direction of the inner hole is formed in the crank, the bottom of the lubricating oil passage further extends towards the end face direction of the two cranks respectively, a plugging cover is arranged at the position of the through hole on the lubricating oil passage, and a plugging ball is arranged in the passage towards the end face direction of the crank, so that the lubricating oil passage forms a seal, and under the action of an external oil pump, pressure lubrication is provided for each bearing bush on the crank;

8. the mode of discharging gas in two cylinders after one-stage compression in the prior art is improved into a mode of discharging gas after two-stage compression, and specifically, the bottom of a low-pressure piston cylinder body is provided with an air inlet valve plate which is opened and closed towards the inner side of the cylinder body, a valve plate which is positioned at one side of a low-pressure piston is provided with an air outlet valve plate which is opened and closed towards an airflow cavity, and a valve plate which is positioned at one side of a high-pressure piston is provided with an air inlet valve plate which is opened and closed towards a high-pressure piston cylinder and an air outlet valve plate which is communicated with the air outlet cavity, so that the gas in the low-pressure piston cylinder enters the high-pressure piston cylinder through the airflow cavity after passing through the first-stage compression piston cylinder, and is discharged after flowing into the air outlet cavity from the high-pressure piston cylinder after secondary compression, and the alternating motion from a lower, the two-stage compressed gas obviously improves the exhaust pressure of the air compressor;

9. the cylinder head is cooled in real time through an external fan in the compression process, all parts heated due to the alternate reciprocating motion of the piston and the heat generated by the compressed gas are cooled, and the high-pressure gas subjected to secondary compression by the high-pressure piston flows back to the exhaust cavity and is then discharged, so that the exhaust temperature is effectively reduced, the operating condition of each component such as a bearing is further improved, the service life of each component is prolonged, and the operating stability of the whole machine is ensured;

10. the stroke limiting plates are respectively arranged on the exhaust valve plates, so that the stroke of the exhaust valve plates is limited by the stroke limiting plates when the exhaust valve plates are opened, and the opening angle of the exhaust valve plates is controlled, so that the piston cylinder is ensured to exhaust outwards stably, the valve plates are ensured to be closed timely, and the compression efficiency of the whole machine is ensured;

11. arranging a dustproof oil seal at the outer side of the bearing, wherein the dustproof oil seal is formed by vulcanizing a rubber piece and a supporting framework, so that the dustproof oil seal extends along the circumferential direction of the shaft surface of the maintenance-free bearing to realize the sealing between the maintenance-free bearing and the outer side of the motor spindle;

12. adopt a split type bent axle transmission structure of multiple spot support, the intensity that the guarantee multiple spot supported, this structure has effectively solved drive disk assembly simultaneously because of processing and assembly error, leads to two cranks shape and position deviation too big, causes the big, the low technical problem in life-span of operation vibration.

Drawings

FIG. 1 is a cross-sectional view of a prior art piston air compressor cylinder with a cross-sectional structure;

FIG. 2 is a schematic view of a piston rod arrangement of a piston air compressor in accordance with a preferred embodiment of the present invention;

FIG. 3 is a side view illustrating a side structure of a piston connecting rod structure of the piston air compressor shown in FIG. 2;

FIG. 4 is a sectional view showing a sectional structure in the direction A-A of FIG. 3;

FIG. 5 is a schematic diagram illustrating the configuration of a counterweight in the piston rod arrangement of the piston air compressor shown in FIG. 2;

FIG. 6 is a state diagram illustrating the piston rod structure of the piston air compressor shown in FIG. 2 rotated 90 degrees;

FIG. 7 is a state diagram illustrating the piston rod structure of the piston air compressor shown in FIG. 2 rotated 180 degrees;

FIG. 8 is a state diagram illustrating the piston rod structure of the piston air compressor shown in FIG. 2 after 270 degrees of rotation;

fig. 9 is a schematic view showing the structure of an oil-free two-stage air compressor using a piston link structure of a piston air compressor in accordance with still another preferred embodiment of the present invention;

fig. 10 is a plan view illustrating a top view structure of the oil-free two-stage air compressor in the preferred embodiment shown in fig. 9;

FIG. 11 is a partial cross-sectional view showing the partial cross-sectional structure of FIG. 10;

fig. 12 is a schematic view illustrating a structure of a multi-point supporting crankshaft of an oil-free air compressor in accordance with another preferred embodiment of the present invention;

fig. 13 is a schematic view illustrating a structure in which a multi-point support crankshaft and a connecting rod are connected to the oilless air compressor shown in fig. 12.

Fig. 14 is a sectional view showing a sectional structure of a two-stage compressed air compressor according to another preferred embodiment of the present invention.

Detailed Description

An embodiment of a two-stage compressed air compressor according to the invention will now be described with reference to the accompanying drawings. Those of ordinary skill in the art will recognize that the described embodiments can be modified in various different ways, without departing from the spirit and scope of the present invention. Accordingly, the drawings and description are illustrative in nature and not intended to limit the scope of the claims. Furthermore, in the present description, the drawings are not to scale and like reference numerals refer to like parts.

It should be noted that, in the embodiments of the present invention, the expressions "first" and "second" are used to distinguish two entities with the same name but different names or different parameters, and it is understood that "first" and "second" are merely for convenience of description and should not be construed as limitations of the embodiments of the present invention, and the descriptions thereof in the following embodiments are omitted.

The piston connecting rod structure of the piston type air compressor in the preferred embodiment of the invention is provided aiming at the problems of large operation vibration and short service life of the piston type air compressor in the prior art under the actual working condition. It is known that the main cause of vibration in piston air compressors is due to the inertia forces or moments of inertia of the unbalanced masses of the crank-link mechanism. Therefore, to eliminate or reduce the vibration of the air compressor, the first considered main method is to balance the structure of the crank link, thereby eliminating or limiting the unbalanced inertial force of the rotating parts or the reciprocating mechanism to limit the vibration within the allowable range.

The preferred embodiment of the invention realizes the reduction of the distance between the axial leads of the two cylinder pistons by arranging the two cylinder pistons in parallel and oppositely, so as to further balance the first-order reciprocating inertia force, the second-order reciprocating inertia force and the rotating inertia moment on the basis of balancing the first-order reciprocating inertia force, the rotating inertia force and the second-order reciprocating inertia moment.

Fig. 2 is a schematic view showing a piston rod structure of a piston type air compressor according to a preferred embodiment of the present invention. As shown in fig. 2, the piston connecting rod structure of the piston type air compressor according to the preferred embodiment of the present invention includes two rows of pistons and a crankshaft 10 connected to the pistons, and the two rows of pistons are connected to the crankshaft 10 through connecting rods, respectively. Specifically, fig. 2 shows the connecting rod arrangement in a non-operating state, in which two rows of pistons are seen to be arranged in parallel opposition along opposite sides of the axis of the crankshaft 10.

Fig. 3 is a side view showing a side structure of a piston connecting rod structure of the piston type air compressor shown in fig. 1. Fig. 4 is a sectional view showing a sectional structure in a direction a-a of fig. 3. As can be seen from fig. 3 and 4, the crankshaft 10 is formed with a plurality of inflection points including two first cranks 11 and a second crank 12 located between the two first cranks 11, and the two pistons are respectively defined as a first piston 21 and a second piston 22 according to the direction shown in fig. 2, then the connecting rod connecting the first piston 21 and the first crank 11 is defined as a first connecting rod 31, and the connecting rod connecting the second piston 22 and the second crank 12 is defined as a second connecting rod 32, as shown in the figure, the first connecting rod 31 and the second connecting rod 32 of the two pistons can adopt different shapes or material proportions to achieve the same mass and gravity center, in the preferred embodiment, the first connecting rod 31 is "V" shaped, and the small end connected with the pistons is branched to form two large ends after extending towards the direction of the crankshaft 10 and respectively connected with the two first cranks 11 by bolts 23, and the second connecting rod 31 is long and straight, i.e. a small end connected to the second piston 22 and a large end connected to the second crank 122 via a bolt 23.

With continued reference to fig. 4, the first crank 11 and the first connecting rod 31 are respectively formed with first inner holes 13 at positions corresponding to the two large ends, and first bearing bushes 14 are disposed in the two first inner holes 13, that is, the two large ends of the first connecting rod 31 are connected to the two first cranks 11 by bolts respectively penetrating through the two first inner holes 13 to be fixed; similarly, a second inner hole 15 is formed at a position of the second crank 12 corresponding to the large end of the second connecting rod 32, a second bearing bush 16 is arranged in the second inner hole 15, and the large end of the second connecting rod 32 is connected with the second crank 12 through a bolt penetrating through the second inner hole 15 to be fixed.

With continued reference to fig. 4, two through holes 17 with opposite opening directions are formed on the end surfaces of the two first cranks 11, and a lubricating oil passage 18 perpendicular to the extending direction of the first inner hole 13 is formed in each through hole 17, which can also be said that the through holes 17 on the two first cranks 11 extend to the bottom in the direction of the other crank, and then extend in the direction of the end surface of the first crank 11 and the direction of the second crank 12 to form two long and narrow passages, and wherein the passages of the two lubricating oil passages 18 extending in the direction of the second crank 12 converge at the position of the second inner hole 15. In the lubricating oil passage 18, the position of the through hole 17 is sealed by a blocking cover 171, and a passage leading to the end face direction of the first crank 11 is sealed by a blocking ball 172, so that the lubricating oil passage 18 forms a sealed oil passage by the blocking cover 171 and the blocking ball 172, and thus, pressure lubrication is realized for the bearing bushes on the first crank shaft 11 and the second crank shaft 12 under the action of an external oil pump.

In the preferred embodiment, setting the offset distance between the first piston 21 and the second piston 22 as e, then setting the hole center distance between the large end and the small end of the first connecting rod 31, or between the large end and the small end of the second connecting rod 32 as l, and setting the crank rotation radius as r, the included angle α between the first crank 11 and the second crank 12 satisfies: cos (a/2) ═ e/(l + r). That is, by changing the size of the angle between the first crank 11 and the second crank 12, the first piston 21 and the second piston 22 can be moved toward each other at a constant speed to reduce the running vibration, and, on the basis of this, it is possible to further reduce the running vibration by adding a balance weight to the crank first crank 11 and the crank second crank 12. FIG. 5 is a schematic diagram illustrating the configuration of a counterweight in the piston rod arrangement of the piston air compressor shown in FIG. 2. The balance weight 19 is provided at the crank position of the crankshaft, and the rotational inertia force generated by the balance weight 19 is balanced with the rotational inertia force generated by the first connecting rod 31 and the second connecting rod 32 during the alternate reciprocating motion of the first connecting rod 31 and the second connecting rod 32. In other embodiments of the present invention, the same technical effect can be achieved by way of the counterweight, in addition to the way of adding the counterweight.

Fig. 6 to 8 show the piston rod structure according to the preferred embodiment of the present invention rotated by 90 degrees, 180 degrees and 270 degrees from the initial state, respectively. Referring to fig. 6 to 8, in actual conditions, the first connecting rod 31 and the second connecting rod 32 perform alternating reciprocating constant-speed motion, so that the two pistons perform corresponding alternating reciprocating constant-speed motion, and as the first connecting rod 31 is in a cross-over type, the first connecting rod 31 gives way for the motion of the second connecting rod 32 during the alternating motion.

In different embodiments of the present invention, besides the way of opposing the piston cylinders in parallel, a way of offset distribution of two cylinders may also be adopted, that is, the air compressor main shaft is used as the axis, and the two cylinders are offset distributed by using the air compressor main shaft as the axis, so that the purpose of reducing the distance between the axes of the two cylinders' pistons can also be achieved. Fig. 9 is a schematic view showing the structure of an oil-free two-stage air compressor using a piston rod structure of a piston air compressor according to still another preferred embodiment of the present invention. Fig. 10 is a plan view illustrating a top view structure of the oil-free two-stage air compressor in the preferred embodiment shown in fig. 9. Fig. 11 is a partial sectional view showing the partial sectional structure of fig. 10. Referring to fig. 9 to 11, the whole machine of the present invention is placed on a pair of front rubber shock-absorbing pads 51 and a pair of rear rubber shock-absorbing pads 52, and two cylinder pistons (61, 62) are distributed in an offset manner by taking the axis of an air compressor as an axis, and as an extension of the application of the piston connecting rod structure, the offset two cylinder pistons are also prepared into the same mass by adopting different material densities, so that the first-order reciprocating inertia force and the rotating inertia force are balanced, and the vibration amplitude of the whole machine in the running state is reduced. One end of the main shaft 40 is engaged with the motor 50, and the other end is engaged with the crankshaft 10, so that the main shaft 40 drives the crankshaft 10 to rotate under the driving of the motor 50, and the connecting rod connected with the crankshaft 10 performs alternating reciprocating constant-speed motion, so that the biased two-cylinder piston performs alternating reciprocating constant-speed motion, and the gas in the cylinder is compressed.

In order to ensure that the bearing can be pressed on the crank during assembly, a split crank is also adopted theoretically, but if the split crank is adopted, the performance life is poor due to the fact that the machining and the assembly are difficult to ensure the integrity and the form and position tolerance are overlarge. In order to solve the technical problem, the invention correspondingly provides a multipoint support crankshaft structure of the oil-free air compressor in a preferred embodiment. Fig. 12 is a schematic view illustrating a structure of a multi-point supporting crankshaft of an oil-free air compressor in accordance with another preferred embodiment of the present invention. Fig. 13 is a schematic view illustrating a structure in which a multi-point support crankshaft and a connecting rod are connected to the oilless air compressor shown in fig. 12. Referring to fig. 12 and 13, the crank structure 100 is connected to the compressor connecting rod 200, the crank structure 100 is configured in three stages, for convenience of description, three stages of the crank structure are defined by its shape as a third crank 101, a fourth crank 102, and a fifth crank 103 connecting the third crank 101 and the fourth crank 102, the third crank 101 and the fourth crank 102 are oppositely disposed with respect to the fifth crank 103, as shown in the figure, a butt joint position of the third crank 101 and the fifth crank 103 forms a first eccentric journal 104, a butt joint position of the fifth crank 103 and the fourth crank 102 forms a second eccentric journal 105, and an end of the third crank 101 not connected to the fifth crank 103 and an end of the fourth crank 102 not connected to the fifth crank 103 form a main journal 106, the main journal 106 corresponds to the main shaft after assembly, a support bearing 107 may be added on the main journal 106, further, a support bearing 107 may be provided on the outer journal of the third crank 101.

In this embodiment, the third crank 101 and the fifth crank 103, and the fifth crank 103 and the fourth crank 102 are connected by forming an interference structure with the transmission positioning pin 108, and are fixed by pressing with the inner ring of the bearing. Specifically, the multi-point supported crankshaft is provided with an eccentric positioning through hole structure on an eccentric crank, and the crankshaft structure is formed by processing two main journals, eccentric crank journals and crank eccentric positioning holes by an integral crankshaft, and further performing heat treatment, surface treatment and the like. And after the finished product is qualified, cutting and separating along the central line of the crank, thereby ensuring the tolerance consistency of the two parts of the separated crank. The multi-point supported crankshaft can adopt the following steps during assembly: the maintenance-free bearing inner ring and a half crank of the third crank 101 are pressed and mounted, a transmission positioning pin shaft 108 is pressed into the eccentric positioning through hole structure in the crank in an interference mode for positioning, and then a half crank of the fifth crank 103 is pressed into the crank. Thereafter, the other half of the fifth crank 103 is assembled with the half of the fourth crank 102 accordingly. In addition, optionally, the transmission positioning pin 108 is flanged and riveted to ensure the integral strength and prevent the separation. The structure process can guarantee the coaxiality of the two separated half crankshaft cranks after press mounting and the coaxiality of the positioning pin shaft, and then can guarantee the coaxiality of the two fulcrum shaft diameters after assembly, so that the transmission operation is stable. In addition, preferably, the maintenance-free bearing of the structural process adopts a maintenance-free double-row maintenance-free bearing, so that two roller bearing raceways in the maintenance-free bearing are uniformly distributed at two ends of two separated half cranks, and the stress balance strength of the crankshaft is reliable.

In practical application, although two rows of pistons can alternately reciprocate at a constant speed, the technical problems that exhaust pressure is insufficient due to insufficient gas compression and exhaust temperature is overhigh due to overheating of equipment are still solved, and the long-term existence of the factors can further cause additional load on components such as a bearing and the like in the motion process of the piston, even influence the service life of the components and the running stability of the whole machine.

In view of the above problem, it is conceivable to increase the exhaust pressure by further compressing the gas, and to decrease the exhaust temperature by lowering the temperature or conducting the gas. Therefore, in the embodiment of the invention, a two-stage compressed air compressor using the crankshaft structure is further provided. Fig. 14 is a sectional view showing a sectional structure of a two-stage compressed air compressor according to another preferred embodiment of the present invention. As shown in fig. 10, 11 and 14, the two-stage compression air compressor in the preferred embodiment includes an offset two-cylinder piston, which is defined as a low pressure piston 61 and a high pressure piston 62, respectively, the high pressure piston 62 and the low pressure piston 61 are fixed to a housing 64 by a tightening sleeve 63 and a plurality of bolts, the high pressure piston 62 and the low pressure piston 61 are connected to an eccentric link 66 by a roller bearing 65, and a maintenance-free bearing 67 is provided at the position where the high pressure piston and the low pressure piston are connected to a crankshaft, on the motor spindle 40, and outside the motor spindle 40, and a dust-proof oil seal 68 is provided outside the maintenance-free bearing 67.

The top of the two-cylinder piston is provided with a valve plate 69 covering the two-cylinder piston, the valve plate 69 is fixed by a cylinder cover 70, and the cylinder cover 70 is provided with a discharge port 71. The valve plate 69 is spaced from the top cover of the air compressor housing 64 to define a cavity area between the valve plate 69 and the top cover of the air compressor housing 64, which is defined as the air flow chamber 72.

The high pressure piston 62 and the low pressure piston 61 are respectively connected to an eccentric connecting rod 66 through a piston pin 85, and the crankshaft 10 is connected to the eccentric connecting rod 66 and the motor spindle 40, so that the eccentric connecting rod 66 is driven by the crankshaft 10 to alternately rotate and reciprocate when the motor spindle 40 rotates, so that the low pressure piston 61 and the high pressure piston 62 alternately reciprocate between respective top dead center and bottom dead center.

The gas is drawn into the housing 64 from the inlet connector 73 of the air compressor, enters the housing 64 through a plurality of muffling holes 74 in the housing 64, and is discharged to the low pressure piston 61. Referring to fig. 12, a first intake valve sheet 75 is disposed at the bottom of the cylinder of the low pressure piston 61, the first intake valve sheet 75 can be fixedly connected to the bottom of the cylinder of the low pressure piston 61 in an opening and closing manner, and in a non-pressure-bearing state, the first intake valve sheet 75 is attached to the bottom of the cylinder of the low pressure piston 61, that is, at this time, the cylinder of the low pressure piston 61 is sealed by the first intake valve sheet 75.

With continued reference to fig. 12, the valve plate 69 is formed with three through holes, one of which for exhaust is located on the valve plate 69 on the side of the low pressure piston 61, defining a first exhaust port 76; the remaining two through-holes are formed in the valve plate 69 on the side of the high-pressure piston 62 and are defined as a second exhaust port 77 and a third exhaust port 78, respectively, and as seen from the drawing, the first exhaust port 76, the second exhaust port 77 and the third exhaust port 78 are disposed so as to communicate the piston cylinder and the air flow chamber, respectively. A first exhaust valve plate 79 is fixed on the first exhaust port 76 in a covering manner, and the first exhaust valve plate 79 can be opened and closed towards one side of the airflow cavity 72; a second air inlet valve plate 80 is fixed on the second air outlet 77 in a covering manner, and the second air inlet valve plate 80 is positioned at the bottom of the valve plate 69 and can be opened towards one side of the cylinder body of the high-pressure piston 62; the third exhaust port 78 is covered and fixed with a second exhaust valve plate 81, and the second exhaust valve plate 81 is located on the top of the valve plate 69 and can be opened toward the airflow chamber 72 side. Similar to the first intake valve sheet 75, in an unpressurized state, the first exhaust valve sheet 79 covers the top of the low-pressure piston 61 to seal between the low-pressure piston 61 and the airflow chamber 72, the second intake valve sheet 80 covers the bottom of the valve plate 69 to seal between the airflow chamber 72 and the cylinder of the high-pressure piston 62, and the second exhaust valve sheet 81 covers the top of the valve plate 69 to seal between the airflow chamber 72 and the cylinder of the high-pressure piston 62.

In order to limit the opening angle of each exhaust valve plate, a stroke limiting plate 82 may be disposed on the first exhaust valve plate 79 and the second exhaust valve plate 81, and the stroke limiting plate 82 is also disposed above the valve plate 69 and is inclined. One end of the stroke limiting plate 82 is fixed to the valve plate 69, and the other end thereof extends in an oblique direction above the exhaust valve plate, so that an area formed between the plate surface of the stroke limiting plate 82 and the surface of the exhaust valve plate is an opening area of the exhaust valve plate. The first exhaust valve plate 79 and the second exhaust valve plate 81 are turned over towards the direction of the airflow cavity 72 and limited by the stroke limiting plate 82 above the first exhaust valve plate and the second exhaust valve plate, so that stable exhaust of the piston cylinder to the airflow cavity is guaranteed, timely closing of the valve plates is guaranteed, and compression efficiency of the whole machine is guaranteed. Further, a self-lubricating piston ring 83 and a guide ring 84 are provided on both the high-pressure piston 62 and the low-pressure piston 61.

When the reciprocating engine works, the high-pressure piston 62 and the low-pressure piston 61 are driven by the crankshaft connecting rod mechanism to alternately reciprocate up and down. When the low-pressure piston 61 moves from the bottom dead center to the top dead center, the volume in the cylinder increases to generate negative pressure, and gas pushes away the first air inlet valve plate 75 from the lower part of the low-pressure piston 61 and is sucked into the airflow cavity 72; when the low-pressure piston 61 moves from the bottom dead center to the top dead center, the volume in the cylinder is reduced, the gas is extruded, the gas pressure is increased until the first exhaust valve plate 79 is pushed to be discharged into the gas flow chamber 72, and at this time, the primary compression of the gas in the first-stage cylinder is completed. Meanwhile, the high-pressure piston 62 moves from the top dead center to the bottom dead center, at this time, the volume in the cylinder increases to generate negative pressure, and under the combined action of the force of the primary compressed gas, the gas compressed by the primary compressed gas in the airflow cavity 72 is sucked into the cylinder from the opening of the second air inlet valve plate 80; when the high pressure piston 62 moves from the bottom dead center to the top dead center, the volume in the cylinder decreases, the gas is squeezed again, the gas pressure increases until the second exhaust valve plate 81 is pushed to exhaust into the gas flow chamber 72 again, and the second compression of the gas is completed at this time. The above process repeats as the piston reciprocates, with the gas being continually compressed and eventually expelled through the discharge port 71.

8. the mode of discharging gas in two cylinders after one-stage compression in the prior art is improved into a mode of discharging gas after two-stage compression, and specifically, the bottom of a low-pressure piston cylinder body is provided with an air inlet valve plate which is opened and closed towards the inner side of the cylinder body, a valve plate which is positioned at one side of a low-pressure piston is provided with an air outlet valve plate which is opened and closed towards an airflow cavity, and a valve plate which is positioned at one side of a high-pressure piston is provided with an air inlet valve plate which is opened and closed towards a high-pressure piston cylinder and an air outlet valve plate which is communicated with the air outlet cavity, so that the gas in the low-pressure piston cylinder enters the high-pressure piston cylinder through the airflow cavity after passing through the first-stage compression piston cylinder, and is discharged after flowing back to the air outlet cavity from the high-pressure piston cylinder after secondary compression, and the alternate movement of the, the two-stage compressed gas obviously improves the exhaust pressure of the air compressor;

9. the cylinder head is cooled in real time through an external fan in the compression process, all parts heated due to friction of alternate reciprocating motion of the piston and heat generated by compressed gas are cooled, and high-pressure gas subjected to secondary compression of the high-pressure piston flows back to the exhaust cavity and then is exhausted, so that the exhaust temperature is effectively reduced, further, the operation working conditions of components such as a bearing and the like are improved, the service life of each component is prolonged, and the operation stability of the whole machine is ensured;

10. the stroke limiting plates are respectively arranged on the exhaust valve plates, so that when the exhaust valve plates are opened towards the airflow cavity, the stroke of the exhaust valve plates is limited by the stroke limiting plates, and the opening angle of the exhaust valve plates is controlled, so that the piston cylinder is ensured to exhaust outwards stably, close back in time, reduce leakage, and ensure compression efficiency;

The present invention has been described in detail, and the embodiments are only used for understanding the method and the core idea of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and to implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. The utility model provides a two-stage compression air compressor, two jar pistons in the air compressor box are high pressure piston and low pressure piston respectively, the cylinder body top of high pressure piston and low pressure piston is provided with the valve plate, its characterized in that still includes:

the high-pressure piston and the low-pressure piston are respectively connected with the eccentric connecting rod through piston pins;

a crankshaft respectively connected with the motor spindle and the eccentric connecting rod, the motor spindle rotationally drives the crankshaft to rotate, the valve plate is fixed by the cylinder cover, and an area between the valve plate and the cylinder cover is defined as an airflow cavity, wherein,

when the low-pressure piston moves from the lower dead point to the upper dead point and the high-pressure piston moves from the upper dead point to the lower dead point, gas in the low-pressure piston cylinder body is compressed in a first stage and enters the airflow cavity from the low-pressure piston cylinder body and then enters the cylinder body of the high-pressure piston;

when the low-pressure piston moves from the top dead center to the bottom dead center and the high-pressure piston moves from the bottom dead center to the top dead center, the gas in the high-pressure piston cylinder body is compressed for two stages and is discharged by the high-pressure piston cylinder body.

2. A two-stage compressed air compressor as claimed in claim 1 including on said low pressure piston:

the first air inlet valve plate can be connected with the end part of the cylinder body of the low-pressure piston in a covering manner, and the bottom of the cylinder body of the low-pressure piston is sealed by the first air inlet valve plate in a non-pressure-bearing state;

the first exhaust valve plate can be connected with the valve plate in a covering mode, and the top of the low-pressure piston is sealed through the first exhaust valve plate in a non-pressure-bearing state;

the second air inlet valve plate can be connected with the high-pressure piston in a covering manner and seals the high-pressure piston and the valve plate in a non-pressure-bearing state,

a second vent flap, which can be connected with the valve plate in a covering manner and seals the high-pressure piston and the valve in a non-pressure-bearing state, wherein,

and a first exhaust port corresponding to the first exhaust valve plate is formed on the valve plate on the low-pressure piston side, and a second air inlet corresponding to the second air inlet valve plate and a third exhaust port corresponding to the second exhaust valve plate are formed on the valve plate on the high-pressure piston side.

3. A two-stage compressed air compressor as claimed in claim 2 wherein the first and second discharge flaps are each provided with a distance limiting plate, one end of which is fixed to the valve plate and extends obliquely towards the top of the discharge valve

The first exhaust valve or the second exhaust valve is turned towards the direction of the airflow cavity and limited by the stroke limiting plates above the first exhaust valve or the second exhaust valve.

4. A two-stage compressed air compressor as claimed in claim 2 wherein both the high pressure piston and the low pressure piston are provided with self-lubricating piston rings and guide rings.

5. A two-stage compressed air compressor according to claim 3 wherein said motor shaft is secured to said housing by means of a tensioning sleeve and bolts, and said high pressure and low pressure pistons are mounted to the crankshaft, on said motor shaft, and outside of said motor shaft, respectively, with maintenance-free bearings, wherein,

and a dustproof oil seal is arranged outside the maintenance-free bearing.

6. A two-stage compressed air compressor as claimed in claim 2 wherein the cylinder head is vented, and wherein,

and after the gas subjected to secondary compression in the high-pressure piston enters the high-pressure cavity from the second exhaust valve, the gas is discharged through the discharge port on the cylinder cover.

7. A two-stage compressed air compressor according to any of claims 2 to 6 wherein a plurality of muffling holes are formed in said case, wherein,

and gas enters the box body through the plurality of silencing holes and then enters the low-pressure piston cylinder through the first air inlet valve plate.