Plunger pump structure of airless sprayer

Abstract

The utility model discloses a plunger pump structure of an airless sprayer, which relates to the field of airless sprayers and comprises a pump body, and a first plunger cavity and a second plunger cavity are arranged in the pump body. The driving device is used for driving the crankshaft to rotate; one end of the first plunger is connected to one eccentric shaft neck of the crankshaft, and the other end of the first plunger is inserted into the first plunger cavity to do reciprocating motion; one end of the second plunger is connected to the other eccentric journal of the crankshaft, and the other end of the second plunger is inserted into the second plunger cavity to do reciprocating motion; the liquid inlet assembly is used for sucking paint in a hopper of the airless sprayer into an inner cavity of the pump body; the liquid outlet assembly is used for discharging the coating from the inner cavity of the pump body; one end of the pressure relief assembly is communicated with the inner cavity of the pump body, and the other end is connected with the hopper through a return pipe; and the pressure protection assembly communicates with the pump body inner cavity and is used for keeping the hydraulic pressure of the pump body inner cavity. A multi-plunger structure and a pressure-regulation-free structure are adopted, the overall service life of a product is effectively prolonged, and the rotating speed of a motor is reduced.

Description

Technical Field

[0001] The utility model relates to the field of airless spraying machines, in particular to a plunger pump structure of an airless spraying machine. Background Art

[0002] An airless sprayer is a spraying device that uses a plunger pump to pressurize the paint. The high-pressure paint is transported to the spray gun through a high-pressure hose, and the pressure is released through the nozzle to form atomization, thereby forming a dense coating on the wall surface. Existing airless sprayers usually use compressed air spraying to replace traditional roller coating and brush coating, but this spraying method relies on air compression. The presence of impurities such as water and oil in the air will cause spots or bubbles on the spray surface, and the spraying efficiency is low. In addition, the plunger pump of the existing airless sprayer generally adopts a single plunger structure, which has the defects of low spraying pressure, poor spraying quality, and short service life. Utility Model Content

[0003] The utility model aims to overcome the deficiencies of the prior art and to provide an airless sprayer plunger pump structure, which adopts a multi-plunger structure and a pressure-adjustment-free structure, effectively prolongs the overall life of the product and reduces the speed of the motor.

[0004] The purpose of the utility model is achieved through the following technical solutions: This airless sprayer plunger pump structure includes:

[0005] A pump body, wherein a first plunger cavity and a second plunger cavity are arranged in the pump body, and the first plunger cavity and the second plunger cavity are respectively communicated with the inner cavity of the pump body;

[0006] A driving device disposed on the driving device housing is used to connect and drive a crankshaft disposed in the driving device housing to rotate, and the driving device housing is connected and fixed to the pump body;

[0007] A first plunger, one end of which is connected to an eccentric journal of the crankshaft and the other end of which is inserted into the first plunger cavity for reciprocating motion;

[0008] A second plunger, one end of which is connected to another eccentric journal of the crankshaft, and the other end of which is inserted into the second plunger cavity for reciprocating motion;

[0009] A liquid inlet assembly is installed on the pump body and is connected to the hopper of the airless sprayer, and is used to suck the paint in the hopper into the inner cavity of the pump body;

[0010] A liquid outlet assembly is installed on the pump body and is used to discharge the paint from the pump body cavity;

[0011] A pressure relief assembly, one end of which is connected to the inner cavity of the pump body, and the other end of which is connected to the hopper through a reflux pipe. The pressure relief assembly is controlled by a knob installed on the pump body to open and close, thereby achieving reflux, pressure relief, and exhaust; and

[0012] The pressure protection component is communicated with the inner cavity of the pump body and is used for maintaining the hydraulic pressure in the inner cavity of the pump body.

[0013] As a further technical solution, the driving device includes a motor fixed to the driving device housing and a gear box driven by the motor. The gear box is installed in the driving device housing and is connected to drive the crankshaft.

[0014] As a further technical solution, the first plunger is connected to one end of the first connecting rod through a latch pin, and the other end of the first connecting rod is set on an eccentric journal of the crankshaft through a first bearing sleeve; the second plunger is connected to one end of the second connecting rod through a latch pin, and the other end of the second connecting rod is set on another eccentric journal of the crankshaft through a second bearing sleeve. The latch pin is inserted into a hole at one end of the first plunger / second plunger, the pin sleeve is fixed in a hole at one end of the first connecting rod / second connecting rod, and the retaining ring is clamped in the grooves at both ends of the latch pin.

[0015] As a further technical solution, a plunger sleeve is provided at a position corresponding to the first plunger cavity and the second plunger cavity in the pump body, and a first sealing ring assembly, a plunger sleeve and a second sealing ring assembly are embedded and installed in each plunger sleeve. The first sealing ring assembly is pressed onto the plunger sleeve by the plunger cover, and the plunger sleeve presses the second sealing ring assembly onto the inner wall of the pump body.

[0016] As a further technical solution, a groove is provided on the outer wall of the plunger sleeve for installing the sleeve sealing ring to seal against the inner wall of the pump body. The first sealing ring assembly and the second sealing ring assembly are both interference fit with the corresponding first plunger or second plunger to form a sliding seal.

[0017] As a further technical solution, the liquid outlet assembly includes a liquid outlet control screw sleeve and a liquid outlet connecting screw sleeve installed on the pump body, a control valve seat is installed on the connecting channel between the second plunger cavity and the inner cavity of the pump body through a control valve seat gasket, a control valve ball is installed on the liquid outlet control screw sleeve through a control spring, and the control valve ball rests on the control valve seat to control the connection and disconnection of the connecting channel; the liquid outlet connecting screw sleeve is sealed and connected to the pump body through a liquid outlet sealing ring, and a liquid outlet is provided on the liquid outlet connecting screw sleeve for externally connecting a high-pressure pipe and a spray gun of an airless sprayer. The liquid outlet control screw sleeve is sealed with the pump body through a control sealing ring.

[0018] As a further technical solution, the liquid inlet component includes an inlet valve sleeve installed on the pump body, a liquid inlet port is opened at a position on the pump body corresponding to the inlet valve sleeve, a liquid inlet valve seat is arranged between the inlet valve sleeve and the inner wall of the pump body, and the inlet valve ball is pressed against the inlet valve seat by an inlet spring, so that the liquid inlet port is connected to the inner cavity of the pump body in one way; a liquid inlet valve seat sealing ring is arranged between the inlet valve seat and the inner wall of the pump body, an outer sealing ring is installed on the outer wall of the pump body at a position corresponding to the inlet valve sleeve, which is used to seal the hopper, and a liquid inlet sealing ring is arranged between the inlet valve sleeve and the inner wall of the pump body.

[0019] As a further technical solution, the pressure relief assembly includes a pressure relief nut threadedly connected to the pump body, a pressure relief valve seat installed in the pump body, a pressure relief valve stem slidably arranged in the pump body, a pressure relief valve ball arranged on the pressure relief valve stem for cooperating with the pressure relief valve seat, and a pressure relief sealing ring installed on the outer wall of the pressure relief valve stem and slidingly sealed with the inner wall of the pump body, a pressure relief spring is supported on the outer wall of the pressure relief valve stem, the other end of the pressure relief spring is pressed on the pressure relief nut, a pressure relief gasket is installed between the pressure relief nut and the pump body, and an inner serrated gasket is arranged at the end of the pressure relief valve stem away from the pressure relief valve seat; a rotating rod is sleeved on the tail end of the pressure relief valve stem for connecting a knob, the inner serrated gasket is pressed on the rotating rod, and the pressure relief valve stem is driven by turning the knob, an inner hole is arranged on the pressure relief valve seat to communicate with the inner cavity of the pump body, and the valve cavity formed between the pressure relief valve seat and the pressure relief valve stem is communicated with the return pipe.

[0020] As a further technical solution, the pressure protection assembly includes a pressure protection sleeve, a pressure protection valve stem and a micro switch. The pressure protection sleeve is threadedly connected to the pump body, one end of the pressure protection valve stem extends into the inner cavity of the pump body, and the other end passes through the pressure protection sleeve and is used to resist the switch button of the micro switch. The micro switch is supported on the pressure protection sleeve through a switch fixing plate, and the micro switch is fixed to the switch fixing plate by screws and nuts. The micro switch is used to electrically connect and control the drive device; a pressure protection spring is supported between the pressure protection sleeve and the pressure protection valve stem to allow the pressure protection valve stem to slide relative to the pressure protection sleeve.

[0021] As a further technical solution, a step is provided on the outer wall of the pressure protection valve stem, one end of the pressure protection spring is against the step, and the other end of the pressure protection spring is against the inner wall of the pressure protection screw sleeve, and the step cooperates with the inner wall of the pump body and the lower surface of the pressure protection screw sleeve to limit the upward and downward sliding stroke of the pressure protection valve stem; a first washer, a pressure protection O-ring and a second washer are sequentially provided on the outer wall of the pressure protection valve stem extending into the pump body cavity to achieve sliding sealing. The screw passes through the switch fixing plate and the micro switch and is locked with a nut to fix the micro switch to the switch fixing plate.

[0022] The beneficial effects of the utility model are:

[0023] 1. Two plungers are arranged in the pump body. The paint is pressed into the liquid outlet assembly through the reciprocating motion of the second plunger, and then pressed out of the liquid outlet through the reciprocating motion of the first plunger. The two plungers work at the same time, which can make the liquid enter the plunger pump more easily, so as to reduce the suction requirements of the liquid inlet, and achieve the purpose of reducing the output power of the motor. It can not only save energy, but also increase the amount of liquid entering the pump body. The liquid material is pressurized quickly, and the liquid material can be pressurized to the pressure required for spraying atomization in a short time, and its working efficiency is greatly improved;

[0024] 2. The pressure in the pump body can be set through the pressure protection component. When the set pressure is reached, the micro switch is triggered and the motor automatically stops running. When the pressure is insufficient, it starts running again. No manual control is required, which is convenient and quick to use.

[0025] 3. With the help of the pressure relief component, air can be returned to the hopper at the beginning of spraying to ensure the spraying quality and reduce paint waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The three-dimensional structure of the utility model is shown in FIG. Figure 1 .

[0027] Figure 2 The three-dimensional structure of the utility model is shown in FIG. Figure 2 .

[0028] Figure 3 It is a schematic diagram of the main structure of the utility model.

[0029] Figure 4 for Figure 3 KK cross-sectional view.

[0030] Figure 5 for Figure 3 MM cross-sectional view.

[0031] Figure 6 for Figure 3 NN cross-sectional view.

[0032] Description of the accompanying drawings: motor 1, gear box 2, first bearing 3, crankshaft 4, first connecting rod 5, second bearing 6, retaining ring 7, latch 8, pin sleeve 9, first plunger 10, plunger cover 11, second plunger 12, first sealing ring assembly 13, outer sleeve sealing ring 14, plunger outer sleeve 15, plunger sleeve 16, second sealing ring assembly 17, liquid outlet control screw sleeve 18, control sealing ring 19, control spring 20, control valve ball 21, control valve seat 22, control valve seat gasket 23, liquid outlet connecting screw sleeve 24, liquid outlet sealing ring 25, rotating rod 26, inner serrated washer 27, pressure relief nut 28, pressure relief gasket 29, pressure relief spring 30, pressure relief sealing ring 31, pressure relief valve stem 3 2. Pressure relief valve ball 33, knob 34, pressure relief valve seat 35, first gasket 36, pressure protection O-ring 37, second gasket 38, pressure protection valve stem 39, pressure protection spring 40, pressure protection screw sleeve 41, micro switch 42, switch fixing plate 43, nut 44, screw 45, liquid inlet valve seat 46, second connecting rod 47, first plunger cavity 48, second plunger cavity 49, drive device housing 50, liquid inlet sealing ring 51, liquid inlet valve screw sleeve 52, liquid inlet valve ball 53, liquid inlet valve seat sealing ring 54, liquid inlet spring 55, reflux pipe 56, pump body 57, liquid outlet 58, outer sealing ring 59, liquid inlet 60, pump body inner cavity 61, connecting channel 62, switch button 63. DETAILED DESCRIPTION

[0033] The utility model will be described in detail below with reference to the accompanying drawings:

[0034] Example: As attached Figures 1 to 6 As shown, the structure of the airless sprayer plunger pump includes a motor 1, a gear box 2, a first bearing 3, a crankshaft 4, a first connecting rod 5, a second bearing 6, a retaining ring 7, a latch 8, a pin sleeve 9, a first plunger 10, a plunger cover 11, a second plunger 12, a first sealing ring assembly 13, a jacket sealing ring 14, a plunger jacket 15, a plunger sleeve 16, a second sealing ring assembly 17, a liquid outlet control screw sleeve 18, a control sealing ring 19, a control spring 20, a control valve ball 21, a control valve seat 22, a control valve seat gasket 23, a liquid outlet connecting screw sleeve 24, a liquid outlet sealing ring 25, a rotating rod 26, an inner serrated gasket 27, a pressure relief nut 28, a pressure relief gasket 29, a pressure relief spring 30, a pressure relief sealing ring 31, a pressure relief valve stem 32, and a pressure relief valve ball 33. , knob 34, pressure relief valve seat 35, first gasket 36, pressure protection O-ring 37, second gasket 38, pressure protection valve stem 39, pressure protection spring 40, pressure protection screw sleeve 41, micro switch 42, switch fixing plate 43, nut 44, screw 45, liquid inlet valve seat 46, second connecting rod 47, first plunger cavity 48, second plunger cavity 49, drive device housing 50, liquid inlet sealing ring 51, liquid inlet valve screw sleeve 52, liquid inlet valve ball 53, liquid inlet valve seat sealing ring 54, liquid inlet spring 55, reflux pipe 56, pump body 57, liquid outlet 58, outer sealing ring 59, liquid inlet 60, pump body inner cavity 61, connecting channel 62, switch button 63, drive device, liquid inlet assembly, liquid outlet assembly, pressure relief assembly and pressure protection assembly.

[0035] Reference Figure 4 A first plunger cavity 48, a second plunger cavity 49 and a pump body inner cavity 61 are provided in the pump body 57, and the first plunger cavity 48 and the second plunger cavity 49 are respectively communicated with the pump body inner cavity 61. Further, the drive device includes a motor 1 and a gear box 2, the motor 1 is fixed on the drive device housing 50, the drive device housing 50 is connected and fixed to the pump body 57, the gear box 2 is installed in the drive device housing 50, the output shaft of the motor 1 drives the gear box 2, the gear box 2 is connected to drive the crankshaft 4 to rotate, and the output shaft of the motor 1, the gear box 2 and the crankshaft 4 are all supported by bearings.

[0036] The first plunger 10 is connected to the right end of the first connecting rod 5 through the latch 8, and the left end of the first connecting rod 5 is sleeved on an eccentric journal of the crankshaft 4 through the first bearing 3. The second plunger 12 is connected to the right end of the second connecting rod 47 through the latch 8, and the left end of the second connecting rod 47 is sleeved on another eccentric journal of the crankshaft 4 through the second bearing 6. Further, the latch 8 is inserted into the hole at one end of the first plunger 10 / second plunger 12, the pin sleeve 9 is fixed in the hole at one end of the first connecting rod 5 / second connecting rod 47, and the retaining ring 7 is clamped in the grooves at both ends of the latch 8. The first plunger 10 is inserted into the first plunger cavity 48 and reciprocates under the drive of the crankshaft 4, and the second plunger 12 is inserted into the second plunger cavity 49 and reciprocates under the drive of the crankshaft 4.

[0037] Preferably, a plunger sleeve 15 is provided at a position corresponding to the first plunger cavity 48 and the second plunger cavity 49 in the pump body 57, and a first sealing ring assembly 13, a plunger sleeve 16 and a second sealing ring assembly 17 are embedded and installed in each plunger sleeve 15. The first sealing ring assembly 13 is pressed against the plunger sleeve 15 by the plunger cover 11, and the plunger sleeve 16 presses the second sealing ring assembly 17 against the inner wall of the pump body 57. Two grooves are provided on the outer wall of the plunger sleeve 15, and the sleeve sealing ring 14 is installed in the grooves, so as to seal relative to the inner wall of the pump body 57. The first sealing ring assembly 13 and the second sealing ring assembly 17 are both interference fit with the corresponding first plunger 10 or second plunger 12 to form a sliding seal.

[0038] like Figure 1 , 2 As shown in FIGS. 3 and 5, the liquid inlet assembly includes a liquid inlet valve sleeve 52 mounted on a pump body 57. A liquid inlet port 60 is provided on the pump body 57 at a position corresponding to the liquid inlet valve sleeve 52. A connecting pipe (not shown in the figure) on the liquid inlet port 60 is connected to the hopper of the airless sprayer, so that the paint in the hopper is sucked into the inner cavity 61 of the pump body. Figure 5 , a liquid inlet valve seat 46 is arranged between the liquid inlet valve screw sleeve 52 and the inner wall of the pump body 57, and the liquid inlet valve ball 53 is pressed against the liquid inlet valve seat 46 through the liquid inlet spring 55, so that the liquid inlet port 60 is in one-way communication with the inner cavity 61 of the pump body. Preferably, a liquid inlet valve seat sealing ring 54 is arranged between the liquid inlet valve seat 46 and the inner wall of the pump body 57, an outer sealing ring 59 is installed on the outer wall of the pump body 57 at a position corresponding to the liquid inlet valve screw sleeve 52, and the outer sealing ring 59 can seal the hopper of the airless sprayer, and a liquid inlet sealing ring 51 is arranged between the liquid inlet valve screw sleeve 52 and the inner wall of the pump body 57.

[0039] like Figure 4As shown, the liquid outlet assembly includes a liquid outlet control screw sleeve 18 and a liquid outlet connecting screw sleeve 24 installed on the pump body 57. A control valve seat 22 is installed on the connecting channel 62 between the second plunger cavity 49 and the inner cavity 61 of the pump body through a control valve seat gasket 23. A control valve ball 21 is installed on the liquid outlet control screw sleeve 18 through a control spring 20. The control valve ball 21 rests on the control valve seat 22 to control the opening and closing of the connecting channel 62 (i.e., to control the opening and closing of the second plunger cavity 49 and the inner cavity 61 of the pump body). Preferably, the liquid outlet connecting screw sleeve 24 is sealed and connected to the pump body 57 through a liquid outlet sealing ring 25. A liquid outlet 58 is provided on the liquid outlet connecting screw sleeve 24. The liquid outlet 58 is used to connect to the high-pressure pipe and spray gun of an airless sprayer to discharge the paint from the inner cavity 61 of the pump body to the spray gun. The liquid outlet control screw sleeve 18 is sealed with the pump body 57 through a control sealing ring 19.

[0040] like Figure 2 , 4 As shown in Figures 5 and 6, the pressure relief assembly includes a pressure relief nut 28 threadedly connected to the pump body 57, a pressure relief valve seat 35 installed in the pump body 57, a pressure relief valve stem 32 slidably arranged in the pump body 57, a pressure relief valve ball 33 arranged on the pressure relief valve stem 32 to cooperate with the pressure relief valve seat 35, and a pressure relief seal ring 31 installed on the outer wall of the pressure relief valve stem 32 and slidingly sealed with the inner wall of the pump body 57. A pressure relief spring 30 is supported on the outer wall of the pressure relief valve stem 32 away from the pressure relief valve seat 35, and the other end of the pressure relief spring 30 is pressed against the pressure relief nut 28, and a pressure relief gasket 29 is installed between the pressure relief nut 28 and the pump body 57. An inner serrated washer 27 is provided at one end (tail end) of the pressure relief valve stem 32 away from the pressure relief valve seat 35, and a rotating rod 26 is sleeved on the tail end of the pressure relief valve stem 32 for connecting the knob 34. The inner serrated washer 27 is pressed against the rotating rod 26. When the knob 34 is turned, the pressure relief valve stem 32 is driven to slide along the inner wall of the pump body 57 through the rotating rod 26. The pressure relief valve seat 35 is provided with an inner hole that is connected to the inner cavity 61 of the pump body. The valve cavity formed between the pressure relief valve seat 35 and the pressure relief valve stem 32 is connected to the reflux pipe 56, so that the pressure relief assembly is connected to the hopper through the reflux pipe 56. At the same time, the pressure relief valve seat 35 is controlled to be opened and closed through the knob 34 to realize reflux, pressure relief and exhaust.

[0041] Reference Figure 6The pressure protection assembly includes a pressure protection screw sleeve 41, a pressure protection valve stem 39 and a micro switch 42. The pressure protection screw sleeve 41 is threadedly connected to the pump body 57. One end of the pressure protection valve stem 39 extends into the inner cavity 61 of the pump body, and the other end penetrates the pressure protection screw sleeve 41 and contacts the switch button 63 of the micro switch 42. The micro switch 42 is supported on the pressure protection screw sleeve 41 through the switch fixing plate 43. The micro switch 42 controls the driving device (motor 1) through electrical connection to automatically maintain the hydraulic pressure of the inner cavity 61 of the pump body. A pressure protection spring 40 is supported between the pressure protection screw sleeve 41 and the pressure protection valve stem 39 to make the pressure protection valve stem 39 slide relative to the pressure protection screw sleeve 41. Preferably, a step is provided on the outer wall of the pressure protection valve stem 39, one end of the pressure protection spring 40 abuts on the step, and the other end of the pressure protection spring 40 abuts on the inner wall of the pressure protection screw sleeve 41, and the step cooperates with the inner wall of the pump body 57 and the lower surface of the pressure protection screw sleeve 41, thereby limiting the upward and downward sliding stroke of the pressure protection valve stem 39. The first gasket 36, the pressure protection O-ring 37 and the second gasket 38 are sequentially provided on the outer wall of the pressure protection valve stem 39 extending into the inner cavity 61 of the pump body to achieve sliding sealing. The screw 45 penetrates the switch fixing plate 43 and the micro switch 42 and is then locked with a nut 44, so that the micro switch 42 is fixedly connected to the switch fixing plate 43.

[0042] The working process of this utility model:

[0043] The plunger pump is driven by the motor 1 to decelerate the gear box 2, and the gear box 2 drives the crankshaft 4, and the eccentric structure (eccentric shaft neck) on the crankshaft 4 drives the first plunger 10 and the second plunger 12 to reciprocate. The paint is sucked into the inner cavity 61 of the pump body from the liquid inlet 60, passes through the liquid inlet component, and is pressed into the liquid outlet component through the reciprocating motion of the second plunger 12. The paint is pressed out of the liquid outlet 58 by the reciprocating motion force of the first plunger 10. When passing through the pressure relief component, since the paint that is just sprayed contains a certain amount of air, the knob 34 can be rotated to make the paint pass through the pressure relief valve seat 35 and the pressure relief valve ball 33 in turn, and then flow into the hopper from the reflux pipe 56. After the air is exhausted, the knob 34 can be rotated in the opposite direction to close the reflux pipe 56, and then normal spraying can be carried out. During spraying, the pressure is set through the pressure protection component. When the pressure in the inner cavity 61 of the pump body reaches the set pressure value, the pressure protection valve stem 39 is lifted up until it hits the switch button 63 of the micro switch 42. The switch button 63 automatically disconnects the circuit and the machine (motor 1) automatically stops running. When the pressure in the inner cavity 61 of the pump body is insufficient, the pressure protection valve stem 39 retreats and the motor 1 starts running again.

[0044] It is understandable that, for those skilled in the art, any equivalent replacement or change to the technical solution and the concept of the utility model should fall within the protection scope of the claims attached to the utility model.

Claims

1. A plunger pump structure for an airless sprayer, characterized in that: include: A pump body (57), wherein a first plunger cavity (48) and a second plunger cavity (49) are arranged in the pump body (57), and the first plunger cavity (48) and the second plunger cavity (49) are respectively communicated with an inner cavity (61) of the pump body; A driving device disposed on a driving device housing (50) is used to connect and drive a crankshaft (4) disposed in the driving device housing (50) to rotate, and the driving device housing (50) is connected and fixed to a pump body (57); A first plunger (10), one end of which is connected to an eccentric journal of the crankshaft (4), and the other end of which is inserted into the first plunger cavity (48) for reciprocating motion; A second plunger (12), one end of which is connected to another eccentric journal of the crankshaft (4), and the other end of which is inserted into the second plunger cavity (49) to perform reciprocating motion; A liquid inlet assembly, mounted on the pump body (57) and connected to the hopper of the airless sprayer, for sucking the paint in the hopper into the inner cavity (61) of the pump body; A liquid discharge assembly, mounted on the pump body (57) and used to discharge the coating material from the inner cavity (61) of the pump body; A pressure relief component, one end of which is in communication with the inner cavity (61) of the pump body, and the other end of which is connected to the hopper via a reflux pipe (56). The pressure relief component is opened and closed by a knob (34) mounted on the pump body (57) to achieve reflux, pressure relief and exhaust; as well as The pressure protection component is communicated with the inner cavity (61) of the pump body and is used to maintain the hydraulic pressure of the inner cavity (61) of the pump body.

2. The airless sprayer plunger pump structure according to claim 1, characterized in that: The drive device comprises a motor (1) fixed to a drive device housing (50) and a gear box (2) driven by the motor (1); the gear box (2) is installed in the drive device housing (50) and is connected to drive a crankshaft (4).

3. The airless sprayer plunger pump structure according to claim 1, characterized in that: The first plunger (10) is connected to one end of a first connecting rod (5) via a latch pin (8), and the other end of the first connecting rod (5) is sleeved on an eccentric journal of a crankshaft (4) via a first bearing (3); the second plunger (12) is connected to one end of a second connecting rod (47) via a latch pin (8), and the other end of the second connecting rod (47) is sleeved on another eccentric journal of the crankshaft (4) via a second bearing (6).

4. The airless sprayer plunger pump structure according to claim 1, characterized in that: A plunger sleeve (15) is provided at a position corresponding to the first plunger cavity (48) and the second plunger cavity (49) in the pump body (57), and a first sealing ring assembly (13), a plunger sleeve (16) and a second sealing ring assembly (17) are embedded and installed in each plunger sleeve (15); the first sealing ring assembly (13) is pressed onto the plunger sleeve (15) by the plunger cover (11), and the plunger sleeve (16) presses the second sealing ring assembly (17) onto the inner wall of the pump body (57).

5. The airless sprayer plunger pump structure according to claim 4, characterized in that: The outer wall of the plunger sleeve (15) is provided with a groove for installing the sleeve sealing ring (14) to seal relative to the inner wall of the pump body (57); the first sealing ring assembly (13) and the second sealing ring assembly (17) are both interference fit with the corresponding first plunger (10) or second plunger (12) to form a sliding seal.

6. The airless sprayer plunger pump structure according to claim 1, characterized in that: The liquid outlet assembly comprises a liquid outlet control screw sleeve (18) and a liquid outlet connecting screw sleeve (24) mounted on a pump body (57); a control valve seat (22) is mounted on a connecting passage (62) between a second plunger cavity (49) and an inner cavity (61) of the pump body; a control valve ball (21) is mounted on the liquid outlet control screw sleeve (18) via a control spring (20); the control valve ball (21) abuts against the control valve seat (22) to control the opening and closing of the connecting passage (62); and a liquid outlet (58) is arranged on the liquid outlet connecting screw sleeve (24) for connecting to a high-pressure pipe and a spray gun of an airless sprayer.

7. The airless sprayer plunger pump structure according to claim 1, characterized in that: The liquid inlet assembly comprises a liquid inlet valve screw sleeve (52) mounted on a pump body (57); a liquid inlet port (60) is provided on the pump body (57) at a position corresponding to the liquid inlet valve screw sleeve (52); a liquid inlet valve seat (46) is arranged between the liquid inlet valve screw sleeve (52) and the inner wall of the pump body (57); a liquid inlet valve ball (53) is pressed against the liquid inlet valve seat (46) via a liquid inlet spring (55) so that the liquid inlet port (60) is in one-way communication with an inner cavity (61) of the pump body; an outer sealing ring (59) is installed on the outer wall of the pump body (57) at a position corresponding to the liquid inlet valve screw sleeve (52) for sealing the hopper.

8. The airless sprayer plunger pump structure according to claim 1, characterized in that: The pressure relief assembly comprises a pressure relief nut (28) threadedly connected to a pump body (57), a pressure relief valve seat (35) installed in the pump body (57), a pressure relief valve stem (32) slidably arranged in the pump body (57), a pressure relief valve ball (33) arranged on the pressure relief valve stem (32) for cooperating with the pressure relief valve seat (35), and a pressure relief sealing ring (31) installed on the outer wall of the pressure relief valve stem (32) and slidingly sealing with the inner wall of the pump body (57); a pressure relief spring (30) is supported on the outer wall of the pressure relief valve stem (32), and the other end of the pressure relief spring (30) is pressed against the pressure relief nut (28). The pressure relief gasket (29) is installed between the pressure relief nut (28) and the pump body (57); an inner serrated gasket (27) is arranged at one end of the pressure relief valve stem (32) away from the pressure relief valve seat (35); a rotating rod (26) is sleeved on the tail end of the pressure relief valve stem (32) for connecting the knob (34); the inner serrated gasket (27) is pressed against the rotating rod (26); the pressure relief valve stem (32) is driven by rotating the knob (34); an inner hole is arranged on the pressure relief valve seat (35) and communicates with the inner cavity (61) of the pump body; and a valve cavity formed between the pressure relief valve seat (35) and the pressure relief valve stem (32) is communicated with the return pipe (56).

9. The airless sprayer plunger pump structure according to claim 1, characterized in that: The pressure protection assembly comprises a pressure protection screw sleeve (41), a pressure protection valve stem (39) and a micro switch (42). The pressure protection screw sleeve (41) is threadedly connected to the pump body (57). One end of the pressure protection valve stem (39) extends into the inner cavity (61) of the pump body, and the other end penetrates the pressure protection screw sleeve (41) and is used to contact a switch button (63) of the micro switch (42). The micro switch (42) is supported on the pressure protection screw sleeve (41) through a switch fixing plate (43), and the micro switch (42) is fixed to the switch fixing plate (43) through a screw (45) and a nut (44). The micro switch (42) is used to electrically connect and control the driving device. A pressure protection spring (40) is supported between the pressure protection screw sleeve (41) and the pressure protection valve stem (39) to enable the pressure protection valve stem (39) to slide relative to the pressure protection screw sleeve (41).

10. The airless sprayer plunger pump structure according to claim 9, characterized in that: A step is arranged on the outer wall of the pressure protection valve stem (39), one end of the pressure protection spring (40) abuts against the step, and the other end of the pressure protection spring (40) abuts against the inner wall of the pressure protection screw sleeve (41), and the step cooperates with the inner wall of the pump body (57) and the lower surface of the pressure protection screw sleeve (41) to limit the upward and downward sliding stroke of the pressure protection valve stem (39); a first gasket (36), a pressure protection O-ring (37) and a second gasket (38) are arranged in sequence on the outer wall of the pressure protection valve stem (39) extending into the inner cavity (61) of the pump body to achieve sliding sealing.

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