A plunger pump

Abstract

The present application relates to the technical field of hydraulic pump, particularly relates to a plunger pump. The plunger pump comprises a motor, a pump body, a rotating shaft assembly, a piston assembly and a pressure relief assembly. The rotating shaft assembly comprises a rotating shaft, a cam and a booster block. The cam and the booster block are sleeved on the rotating shaft. The plunger pump has a booster position and a pressure relief position. In the booster position, the motor drives the rotating shaft to rotate forward, the cam is unlocked in the circumferential direction from the rotating shaft, and the booster block is locked in the circumferential direction on the rotating shaft. In the pressure relief position, the motor drives the rotating shaft to rotate reversely, the cam is locked in the circumferential direction on the rotating shaft, and the booster block is unlocked in the circumferential direction from the rotating shaft. The piston assembly comprises a piston cylinder and a piston rod. The end of the piston rod, which extends out of the piston cylinder, is in contact with the booster block. The pressure relief assembly comprises a pressure relief cylinder, a pressure relief rod and a reset member. When the rotating shaft rotates reversely, the cam drives the pressure relief rod to move in the axial direction against the elastic force of the reset member, so as to open the pressure relief port. The present application adopts mechanical pressure relief. The parts are stable and reliable under high pressure and are not easy to be damaged.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic pump technology, and in particular relates to a plunger pump. Background Technology

[0002] A hydraulic pump is the power component in a hydraulic system, and its performance directly affects the overall performance of the hydraulic system. A piston pump is a type of hydraulic pump that relies on the reciprocating motion of a piston within a cylinder to change the volume of the sealed working chamber, thus achieving oil suction and pressure.

[0003] To prevent damage to the plunger pump and downstream system due to excessive pressure, an existing plunger pump is equipped with a hydraulic solenoid valve. When the pressure in the plunger pump or downstream system exceeds a preset value, the coil of the hydraulic solenoid valve is energized, and the moving iron core overcomes the spring force to attract the stationary iron core, thereby driving the valve core to open the valve port, thus opening the pressure relief channel of the hydraulic system and allowing the cylinder to release pressure.

[0004] Therefore, the structural characteristics of each component in a hydraulic solenoid valve determine the pressure relief of the plunger pump. The stationary and moving iron cores are generally made of brittle materials with weak fracture toughness, impact strength, and bending strength, making them prone to damage under high pressure, resulting in a lower pressure relief of the plunger pump. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a plunger pump that addresses the issue that the solenoid valves used in existing plunger pumps are prone to damage under high pressure, resulting in low pressure relief of the plunger pump.

[0006] To address the aforementioned technical problems, this invention provides a plunger pump, comprising a motor, a pump body, a shaft assembly, a piston assembly, and a pressure relief assembly. The piston assembly and the pressure relief assembly are mounted within the pump body. The shaft assembly includes a shaft, a cam, and a pressure boosting block. The cam and the pressure boosting block are sleeved on the shaft. The output shaft of the motor is connected to the shaft and drives the shaft to rotate clockwise and counterclockwise around its own axis. The plunger pump has a pressure boosting position and a pressure relief position. In the pressure boosting position, the motor drives the shaft to rotate clockwise, the cam is released from circumferential locking with the shaft, and the pressure boosting block is circumferentially locked onto the shaft. In the pressure relief position, the motor drives the shaft to rotate counterclockwise, the cam is circumferentially locked onto the shaft, and the pressure boosting block is released from circumferential locking with the shaft.

[0007] The piston assembly includes a piston cylinder and a piston rod. One end of the piston rod extending out of the piston cylinder contacts and engages with the pressure block. When the shaft rotates forward, the pressure block drives the piston rod to reciprocate axially.

[0008] The pressure relief assembly includes a pressure relief cylinder, a pressure relief rod, and a reset component. The pressure relief rod and the reset component are installed inside the pressure relief cylinder. The pressure relief cylinder is provided with a pressure relief port for the piston cylinder to release pressure. In the pressurization position, the pressure relief rod blocks the pressure relief port. When the rotating shaft reverses, the cam drives the pressure relief rod to move axially against the elastic force of the reset component to open the pressure relief port.

[0009] Optionally, the cam has a first driving surface and a second driving surface. The first driving surface extends along the circumferential direction of the cam and is inclined toward the pressure relief rod. The circumferential extension angle of the first driving surface is less than 360°. The second driving surface is perpendicular to the moving direction of the pressure relief rod. The side of the first driving surface near the pressure relief rod is connected to the second driving surface to guide the pressure relief rod to contact the second driving surface when the cam rotates.

[0010] Optionally, a notch is provided on the outer peripheral wall of the cam, the notch passing through one axial end of the cam near the pressure relief rod. In the pressurization position, the end of the pressure relief rod extends into the notch, the notch forms the first driving surface on the side wall in the reverse direction of the rotating shaft, and the end face of the cam near the pressure relief rod forms the second driving surface.

[0011] Optionally, the pressure relief assembly further includes a rotating component rotatably mounted on the pressure relief rod. The rotation axis of the rotating component is perpendicular to the rotation axis of the cam, and the outer peripheral wall of the rotating component contacts and engages with the first driving surface and the second driving surface when the cam rotates.

[0012] Optionally, it also includes a first stop pin and a first elastic element. The outer wall of the rotating shaft is provided with a first mounting hole extending radially. One end of the first stop pin is inserted into the first mounting hole, and the other end abuts against the inner peripheral wall of the cam. The two ends of the first elastic element abut against the cam and the first stop pin, respectively.

[0013] The inner peripheral wall of the cam is provided with an arc-shaped first stop groove. The radius of the first stop groove gradually increases in the reverse direction of the rotating shaft. The first stop groove smoothly transitions with the inner wall of the cam on one side in the forward rotation direction of the rotating shaft, and forms a first stop step between the other side and the inner wall of the cam. The first stop step is used to stop the first stop pin in a circumferential stop when the rotating shaft reverses.

[0014] Optionally, multiple first stop grooves are provided, and each first stop groove is distributed along the circumferential direction of the cam.

[0015] Optionally, it also includes a second stop pin and a second elastic member. The pressure block is provided with a second mounting hole extending radially. One end of the second stop pin is inserted into the second mounting hole, and the other end abuts against the outer wall of the rotating shaft. The two ends of the second elastic member abut against the pressure block and the second stop pin, respectively.

[0016] An arc-shaped second stop groove is provided on the outer wall of the rotating shaft. The radius of the second stop groove gradually increases along the forward rotation direction of the rotating shaft. The second stop groove smoothly transitions with the outer wall of the rotating shaft on one side in the forward rotation direction, and forms a second stop step between the other side and the outer wall of the rotating shaft. The second stop step is used to stop the second stop pin in a circumferential stop when the rotating shaft rotates forward.

[0017] Optionally, the booster block has a booster surface, which has a non-zero angle with the axis of the piston rod, and the booster surface pushes the piston rod to reciprocate along its axial direction when the booster block rotates.

[0018] Optionally, a steering knuckle is mounted on one end of the piston rod extending out of the piston cylinder. The steering knuckle is ball-jointed to the piston rod, and the side of the steering knuckle facing the pressure surface has an inclined surface adapted to the pressure surface.

[0019] Optionally, the system also includes a rubber sealing ring and multiple metal sealing rings, which are sleeved on the end of the piston rod that extends into the piston cylinder to provide a sealing fit between the piston rod and the piston cylinder. In the axial direction of the piston rod, the rubber sealing ring is installed between two of the metal sealing rings.

[0020] In the plunger pump of the present invention, the forward-rotating motor drives the piston assembly to perform a pressurizing action through the rotating shaft and the pressure boosting block, and the reverse-rotating motor drives the pressure relief assembly to perform a pressure relief action through the rotating shaft and the cam, thereby realizing mechanical pressure relief. Compared with the brittle iron core in the solenoid valve, each part has a greater structural strength, is stable and reliable under greater pressure, and is not easily damaged. Therefore, the plunger pump can withstand a greater pressure relief. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a plunger pump (with the pump body structure hidden) provided in an embodiment of the present invention;

[0022] Figure 2 yes Figure 1 A schematic diagram of the structure after the motor is hidden;

[0023] Figure 3 yes Figure 2 A sectional view;

[0024] Figure 4 yes Figure 2A cross-sectional view from another cutting position;

[0025] Figure 5 yes Figure 2 Schematic diagram of the middle cam

[0026] Figure 6 yes Figure 2 A schematic diagram of the assembly of the rotating shaft and the cam.

[0027] Figure 7 yes Figure 6 A sectional view;

[0028] Figure 8 yes Figure 2 A cross-sectional view of the rotating shaft and the booster block assembled together.

[0029] The reference numerals in the accompanying drawings are as follows:

[0030] 1. Pump body; 11. Oil outlet channel; 12. Pressure relief channel; 13. Oil inlet channel; 14. Oil storage chamber; 2. Motor; 3. Shaft assembly; 31. Shaft; 311. First stop groove; 312. First stop step; 32. Cam; 321. Notch; 322. First drive surface; 323. Second drive surface; 324. Second stop groove; 325. Second stop step; 33. Pressure boosting block; 34. Pressure boosting surface; 35. First stop pin; 36. First elastic element; 37. Second stop pin; 38. Second elastic element; 4. Piston assembly; 41. Piston cylinder; 42. Piston rod; 43. Steering knuckle; 5. Pressure relief assembly; 51. Pressure relief cylinder; 52. Pressure relief rod; 53. Rotating component; 54. Reset component; 6. Metal sealing ring; 7. Rubber sealing ring. Detailed Implementation

[0031] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0032] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a plunger pump, including a motor 2, a pump body 1, a rotating shaft assembly 3, a piston assembly 4, and a pressure relief assembly 5. The piston assembly 4 and the pressure relief assembly 5 are installed inside the pump body 1, and the motor 2 is installed on the pump body 1. The motor 2 is a forward and reverse motor 2.

[0033] The rotating shaft assembly 3 includes a rotating shaft 31, a cam 32, and a booster block 33. The cam 32 and the booster block 33 are sleeved on the rotating shaft 31. The output shaft of the motor 2 is connected to the rotating shaft 31 and is used to drive the rotating shaft 31 to rotate forward and backward around its own axis.

[0034] The plunger pump has a boosting position and a depressurization position. In the boosting position, the motor 2 drives the rotating shaft 31 to rotate forward, the cam 32 is released from the circumferential lock between it and the rotating shaft 31, and the boosting block 33 is circumferentially locked on the rotating shaft 31. Thus, when the rotating shaft 31 rotates forward, the cam 32 does not move and the boosting block 33 rotates with the rotating shaft 31.

[0035] In the pressure relief position, the motor 2 drives the rotating shaft 31 to reverse, the cam 32 is circumferentially locked on the rotating shaft 31, and the pressure boosting block 33 is released from the circumferential lock with the rotating shaft 31. Thus, when the rotating shaft 31 reverses, the cam 32 rotates with the rotating shaft 31, while the pressure boosting block 33 remains stationary.

[0036] like Figure 3 As shown, the piston assembly 4 includes a piston cylinder 41 and a piston rod 42. One end of the piston rod 42 extends out of the piston cylinder 41 and contacts and engages with the pressure boosting block 33. When the rotating shaft 31 rotates forward, the pressure boosting block 33 drives the piston rod 42 to reciprocate along the axial direction. The volume of the sealed working cavity inside the piston cylinder 41 changes to achieve oil suction and oil pressure, thereby increasing the pressure inside the piston cylinder 41.

[0037] like Figure 4 As shown, the pressure relief assembly 5 includes a pressure relief cylinder 51, a pressure relief rod 52, and a reset member 54. The pressure relief rod 52 and the reset member 54 are installed inside the pressure relief cylinder 51. The pressure relief cylinder 51 is provided with a pressure relief port for the piston cylinder 41 to release pressure. When the plunger pump is in the boosting position, the cam 32 is stationary, and the pressure relief rod 52, which is in contact with the cam 32, remains stationary to block the pressure relief port, so that the piston cylinder 41 can be pressurized when suctioning and pressurizing oil.

[0038] When the rotating shaft 31 reverses, the cam 32 drives the pressure relief rod 52 to move axially against the elastic force of the reset member 54, so as to open the pressure relief port, so that the working cavity in the piston cylinder 41 is connected to the outside, thereby relieving pressure.

[0039] When motor 2 drives shaft 31 to rotate forward, pressure booster block 33 rotates while cam 32 remains stationary. When motor 2 drives shaft 31 to rotate in reverse, cam 32 rotates while pressure booster block 33 remains stationary. This allows the pressure relief rod 52, which engages with cam 32 during forward rotation, to remain stationary and block the pressure relief port. The rotating pressure booster block 33 drives piston rod 42 to reciprocate axially within piston cylinder 41, achieving oil suction and pressure relief in piston cylinder 41, thus boosting the pressure of the plunger pump. During reverse rotation, the rotating cam 32 drives pressure relief rod 52 to move axially to open the pressure relief port, allowing the plunger pump to release pressure. Furthermore, by using only motor 2 as a power source to achieve both boosting and depressurizing functions, the overall size of the plunger pump is relatively small, reducing the space requirements for installation.

[0040] It should be noted that the pump body 1 is equipped with an oil storage chamber 14, an oil inlet channel 13, and an oil outlet channel 11. One end of the oil outlet channel 11 is connected to a pressure testing device. The oil storage chamber 14 stores hydraulic oil. The piston cylinder 41 is equipped with an oil inlet communicating with the oil inlet channel 13 and an oil outlet communicating with the oil outlet channel 11. When the volume of the working chamber increases, the hydraulic oil in the oil storage chamber 14 enters the working chamber through the oil inlet, realizing the oil suction of the piston cylinder 41. After oil suction, the piston rod 42 moves in the opposite direction, causing the volume of the working chamber to decrease, thereby increasing the pressure in the working chamber and realizing the pressurization of the plunger pump. The hydraulic oil in the working chamber flows to the oil outlet channel 11 through the oil outlet to transmit the pressure to the pressure testing device. The plunger pump adopts a self-circulating structure. The piston cylinder 41, oil storage chamber 14, oil inlet channel 13 and oil outlet channel 11 are all located inside the pump body 1, so that the hydraulic oil always circulates inside the pump body 1, and the wear parts are all placed in the inner cavity of the pump body 1, eliminating the risk of oil leakage.

[0041] In the plunger pump of the present invention, the forward-rotating motor 2 drives the piston assembly 4 to perform a pressurizing action through the rotating shaft 31 and the pressure boosting block 33, and the reverse-rotating motor 2 drives the pressure relief assembly 5 to perform a pressure relief action through the rotating shaft 31 and the cam 32, thereby realizing mechanical pressure relief. Compared with the brittle iron core in the solenoid valve, each part has a greater structural strength, is stable and reliable under greater pressure, and is not easily damaged. Therefore, the plunger pump can withstand a greater pressure relief.

[0042] In one embodiment, such as Figure 6 As shown, the cam 32 has a first driving surface 322 and a second driving surface 323. The first driving surface 322 extends along the circumference of the cam 32 and is inclined towards the pressure relief rod 52. The circumferential extension angle of the first driving surface 322 is less than 360°. The second driving surface 323 is perpendicular to the moving direction of the pressure relief rod 52. The side of the first driving surface 322 near the pressure relief rod 52 is connected to the second driving surface 323, which guides the pressure relief rod 52 to contact the second driving surface 323 when the cam 32 rotates. Through the special driving surface design, the rotational motion of the cam 32 is converted into the axial linear motion of the pressure relief rod 52, resulting in a simple structure and small space occupation.

[0043] Specifically, when the motor 2 reverses and the cam 32 rotates, the inclined first driving surface 322 pushes the pressure relief rod 52 to overcome the elastic force of the reset member 54 and gradually move downward along its axis to gradually open the pressure relief port until the cam 32 rotates to the point where the second driving surface 323 contacts the pressure relief rod 52. Since the second driving surface 323 is perpendicular to the direction of movement of the pressure relief rod 52, the height of the second driving surface 323 in the direction of movement of the pressure relief rod 52 remains unchanged. Thus, the pressure relief rod 52 remains stationary during the contact with the second driving surface 323, so that the pressure relief port is always open.

[0044] In one embodiment, a notch 321 is provided on the outer peripheral wall of the cam 32, and the notch 321 passes through one axial end of the cam 32 near the pressure relief rod 52. In the pressurized position, the end of the pressure relief rod 52 extends into the notch 321. At this time, the end of the pressure relief rod 52 is not subjected to a force opposite to the elastic force of the reset member 54, so that the pressure relief rod 52 blocks the pressure relief port under the action of the reset member 54. The notch 321 forms a first driving surface 322 on the side wall of the rotating shaft 31 in the reverse direction, and the end face of the cam 32 near the pressure relief rod 52 forms a second driving surface 323.

[0045] In one embodiment, a pressure relief channel 12 is provided inside the pump body 1. One end of the pressure relief channel 12 is connected to the oil outlet channel 11, and the other end is connected to the bottom of the pressure relief cylinder 51 through a pressure relief port. The bottom of the side wall of the pressure relief cylinder 51 is provided with a communication port that communicates with the oil storage chamber 14. The bottom end of the pressure relief rod 52 passes through the pressure relief port and extends into the pressure relief channel 12, and a steel ball is connected to the bottom end of the pressure relief rod 52. The diameter of the steel ball is larger than the diameter of the pressure relief port.

[0046] In the pressurization position, the steel ball on the pressure relief rod 52 blocks the pressure relief port axially upward under the force of the reset member 54. In the pressure relief position, the rotating cam 32 drives the pressure relief rod 52 to move axially downward against the elastic force of the reset member 54, thereby moving the steel ball downward and opening the pressure relief port, so that the hydraulic oil in the piston cylinder 41 can be discharged to the oil storage chamber 14 through the oil outlet channel 11 and the pressure relief channel 12 for pressure relief.

[0047] In one embodiment, the reset member 54 is a compression spring, and the pressure relief rod 52 includes a large diameter section and a small diameter section connected to the lower end of the large diameter section. The compression spring is sleeved on the small diameter section. One end of the compression spring abuts against the step end face between the large diameter section and the small diameter section, and the other end abuts against the bottom wall of the pressure relief cylinder 51. In the pressurized position, the compression spring applies an upward force to the pressure relief rod 52 so that the steel ball blocks the pressure relief port.

[0048] In other embodiments, the reset member 54 may be a rubber block, which is sleeved on the pressure relief rod 52.

[0049] In one embodiment, such as Figure 2 As shown, the pressure relief assembly 5 also includes a rotating member 53, which is rotatably mounted on the pressure relief rod 52. The rotation axis of the rotating member 53 is perpendicular to the rotation axis of the cam 32. When the cam 32 rotates, the outer peripheral wall of the rotating member 53 contacts and engages with the first driving surface 322 and the second driving surface 323, so that the rotating cam 32 pushes the pressure relief rod 52 up and down along its axial direction via the rotating member 53. Because the rotating member 53 is rotatably mounted on the pressure relief rod 52, it converts the circumferential motion of the cam 32 into its own circumferential rotation, transmitting only the axial pushing force to the pressure relief rod 52. The pressure relief rod 52 is not subjected to radial force, thus preventing offset.

[0050] In one embodiment, the rotating component 53 is a bearing, and the end of the pressure relief rod 52 is provided with a radially penetrating rotating hole. The rotating shaft of the bearing is installed in the rotating hole and is positioned towards the side of the pressure relief rod 52 close to the cam 32, so that the outer peripheral wall of the bearing can contact the first driving surface 322 and the second driving surface 323 when the cam 32 rotates.

[0051] In one embodiment, such as Figure 6 and Figure 7 As shown, it also includes a first stop pin 35 and a first elastic member 36. A first mounting hole extending radially is provided on the outer wall of the rotating shaft 31. One end of the first stop pin 35 is inserted into the first mounting hole, and the other end abuts against the inner peripheral wall of the cam 32. The two ends of the first elastic member 36 abut against the cam 32 and the first stop pin 35 respectively.

[0052] The inner wall of the cam 32 is provided with an arc-shaped first stop groove 311. The radius of the first stop groove 311 gradually increases in the reverse direction of the rotating shaft 31. The first stop groove 311 smoothly transitions with the inner wall of the cam 32 on one side in the forward rotation direction of the rotating shaft 31, and forms a first stop step 312 between the other side and the inner wall of the cam 32. The first stop step 312 is used to stop the first stop pin 35 in the circumferential direction when the rotating shaft 31 reverses.

[0053] Specifically, when the motor 2 reverses to drive the rotating shaft 31 to reverse, the first stop pin 35 rotates in the opposite direction along with the rotating shaft 31 to rotate into the first stop groove 311. Under the action of the first elastic member 36, the first stop pin 35 can move radially to always abut against the bottom wall of the first stop groove 311 with the gradually increasing radius, until the first stop pin 35 and the first stop step 312 are circumferentially stopped and engaged, and the cam 32 is locked on the rotating shaft 31, so that the cam 32 rotates with the rotating shaft 31.

[0054] When the motor 2 rotates forward to drive the shaft 31 to rotate forward, the first stop pin 35 rotates in the forward direction and cannot contact the first stop step 312, so that the first stop pin 35 cannot stop the first stop step 312 in the circumferential direction, thereby releasing the lock between the cam 32 and the shaft 31.

[0055] In one embodiment, the first elastic element 36 is a spring, and a raised abutment is provided on the outer peripheral surface of the first stop pin 35. The spring is sleeved on the outer periphery of the first stop pin 35, with one end of the first stop pin 35 abutting against the end face of the abutment and the other end abutting against the bottom of the first mounting hole. When the first stop pin 35 reverses within the first stop groove 311, the spring gradually extends so that the end of the first stop pin 35 always abuts against the bottom wall of the first stop groove 311.

[0056] In one embodiment, multiple first stop grooves 311 are provided, and each first stop groove 311 is distributed along the circumferential direction of the cam 32. Thus, when the first stop pin 35 rotates into any one of the first stop grooves 311, the cam 32 can be circumferentially locked on the rotating shaft 31, reducing the rotation angle of the first stop pin 35 when it changes from the released state to the locked state, and improving the efficiency of the plunger pump in the pressure relief position.

[0057] In one embodiment, such as Figure 8 As shown, it also includes a second stop pin 37 and a second elastic member 38. The pressure block 33 is provided with a second mounting hole extending radially. One end of the second stop pin 37 is inserted into the second mounting hole, and the other end abuts against the outer wall of the rotating shaft 31. The two ends of the second elastic member 38 abut against the pressure block 33 and the second stop pin 37, respectively.

[0058] An arc-shaped second stop groove 324 is provided on the outer wall of the rotating shaft 31. The radius of the second stop groove 324 gradually increases along the forward rotation direction of the rotating shaft 31. The second stop groove 324 smoothly transitions with the outer wall of the rotating shaft 31 on one side in the forward rotation direction, and forms a second stop step 325 between the other side and the outer wall of the rotating shaft 31. The second stop step 325 is used to stop and cooperate with the second stop pin 37 in the circumferential direction when the rotating shaft 31 rotates forward.

[0059] Specifically, one end of the second stop pin 37 passes through the second mounting hole, and under the action of the second elastic member 38, the other end of the second stop pin 37 can always abut against the outer peripheral wall of the rotating shaft 31. When the motor 2 rotates forward to drive the rotating shaft 31 to rotate forward, so that the second stop pin 37 abuts against the second stop groove 324, the second stop step 325 can cooperate with the second stop pin 37 in a circumferential stop, so that the pressure block 33 is locked on the rotating shaft 31, and thus the pressure block 33 can rotate together with the rotating shaft 31.

[0060] When the motor 2 reverses to drive the shaft 31 to reverse, the second stop step 325 of the reversed shaft 31 cannot contact the second stop pin 37, thus releasing the lock between the booster block 33 and the shaft 31.

[0061] In one embodiment, the second elastic element 38 is a compression spring, and a raised first support step is provided on the outer wall of the second stop pin 37. Correspondingly, a second support step is provided on the hole wall of the second mounting hole. The compression spring is sleeved on the second stop pin 37, and its two ends abut against the first support step and the second support step, respectively.

[0062] In one embodiment, the rotating shaft 31 includes a large diameter section and a small diameter section connected to the bottom end of the large diameter section, the cam 32 is sleeved on the outer peripheral surface of the large diameter section, and the pressure block 33 is sleeved on the outer peripheral surface of the small diameter section.

[0063] The rotating shaft assembly 3 also includes a support, which is sleeved on the small-diameter section and fixedly connected to the large-diameter section. Specifically, the end face of the large-diameter section is provided with a threaded hole that extends axially, and the support is provided with a through hole that extends axially. The large-diameter section and the support are connected by bolts. The outer diameter of the support is larger than the inner diameter of the cam 32, and the support can support the cam 32.

[0064] In one embodiment, the shaft assembly 3 further includes a bearing, which is sleeved on the small diameter section and located between the large diameter section and the pressure block 33 in the axial direction of the shaft 31.

[0065] In one embodiment, the booster block 33 includes a booster block 33 body and a mounting block. A mounting groove is formed on the outer wall of the booster block 33 body, and the mounting block is fixed within the mounting groove. The aforementioned second mounting hole is formed on the mounting block. When assembling the plunger pump, the booster block 33 body can be first fitted onto the rotating shaft 31, then the second stop pin 37 and the spring can be mounted on the mounting block, and finally the mounting block can be inserted into the mounting groove, facilitating installation and improving assembly efficiency.

[0066] In one embodiment, two sets of second stop pins 37 and second elastic members 38 are provided, and the two sets of second stop pins 37 are symmetrically distributed along the circumferential direction. Correspondingly, two second mounting holes are provided on the pressure block 33 to balance the force between the pressure block 33 and the rotating shaft 31.

[0067] In one embodiment, the pressure boosting block 33 has a pressure boosting surface 34, which forms a non-zero angle with the axis of the piston rod 42. When the pressure boosting block 33 rotates, the pressure boosting surface 34 pushes the piston rod 42 to reciprocate along its axial direction. Due to the different heights of the pressure boosting surface 34 along the axial direction of the piston rod 42, when the pressure boosting block 33 rotates, points at different heights on the pressure boosting surface 34 contact the piston rod 42, causing the piston rod 42 to move up and down along its axial direction. This changes the volume of the sealed working cavity inside the piston cylinder 41, thereby achieving oil suction and oil pressure.

[0068] The piston cylinder 41 has a variable diameter cavity, including a large diameter cavity and a small diameter cavity connected to the bottom end of the large diameter cavity. A piston block protruding radially outward is provided on the outer peripheral surface of the upper region of the piston rod 42. The piston block is sealed with the large diameter cavity, and the lower end of the piston rod 42 is sealed with the small diameter cavity, so that the piston cylinder 41 and the piston rod 42 form a sealed working cavity.

[0069] When the piston rod 42 moves upward along its axial direction, the volume of the working cavity increases, and the hydraulic oil in the pump body 1 enters the working cavity through the oil inlet at the bottom of the working cavity via the oil inlet channel 13, thus achieving the oil suction action. When the piston rod 42 moves downward along its axial direction, the volume of the working cavity decreases, and the pressure in the working cavity increases. The hydraulic oil in the working cavity enters the oil outlet channel 11 through the oil outlet at the bottom. One end of the oil outlet channel 11 is connected to a pressure testing device to transmit the pressure of the hydraulic oil to the pressure testing device.

[0070] It should be noted that both the oil inlet channel 13 and the oil outlet channel 11 are equipped with check valves, so the hydraulic oil can only flow in one direction.

[0071] In one embodiment, a steering knuckle 43 is installed at one end of the piston rod 42 that extends out of the piston cylinder 41. The steering knuckle 43 is ball-jointed to the piston rod 42. The side of the steering knuckle 43 facing the pressure boosting surface 34 has an inclined surface adapted to the pressure boosting surface 34, so that the steering knuckle 43 can contact the pressure boosting surface 34 when the pressure boosting block 33 rotates to any circumferential angle, thereby increasing the contact area between the piston rod 42 and the pressure boosting block 33 and improving the stability of the piston rod 42 when the pressure boosting block 33 pushes the piston rod 42 axially.

[0072] In one embodiment, the end of the piston rod 42 is spherical, and correspondingly, a spherical groove is provided on the steering knuckle 43. The end of the piston rod 42 is inserted into the spherical groove and is connected to the piston rod 42 by ball joint of the steering knuckle 43.

[0073] In one embodiment, multiple piston rods 42 are provided, and the multiple piston rods 42 are distributed in parallel and spaced apart. Multiple independent piston chambers are provided in the piston cylinder 41. The piston rods 42 are sealed to the corresponding piston chambers. Steering knuckles 43 are installed at the ends of the multiple piston rods 42.

[0074] In one embodiment, four piston rods 42 are provided.

[0075] In one embodiment, the system further includes a rubber sealing ring 7 and a plurality of metal sealing rings 6. The rubber sealing ring 7 and the metal sealing rings 6 are sleeved on one end of the piston rod 42 that extends into the piston cylinder 41, so that the piston rod 42 and the piston cylinder 41 are sealed together. In the axial direction of the piston rod 42, the rubber sealing ring 7 is installed between the two metal sealing rings 6, so that the metal sealing rings 6 protect the rubber sealing ring 7, thereby reducing the wear of the rubber sealing ring 7 under high pressure and extending its service life.

[0076] In one embodiment, the rubber sealing ring 7 is a polytetrafluoroethylene (PTFE) sealing ring.

[0077] In other embodiments, the first driving surface 322 and the second driving surface 323 can be omitted. A special curved surface structure can be designed on the end of the pressure relief rod 52 near the cam 32, including a third driving surface and a fourth driving surface. The third driving surface is set on the outer wall of the pressure relief rod 52 and extends obliquely in the direction of rotation of the cam 32. The fourth driving surface is perpendicular to the rotation axis of the rotating shaft 31 and is connected to the side of the third driving surface near the cam 32. When the cam 32 rotates, it first contacts the third driving surface. Since the third driving surface is oblique, the rotating cam 32 gradually pushes the pressure relief rod 52 downward along the axial direction until it contacts the fourth driving surface.

[0078] In other embodiments, a connecting rod can be provided between the cam 32 and the pressure relief rod 52. One end of the connecting rod is connected to the outer wall of the cam 32, and the other end of the connecting rod is connected to the top of the pressure relief rod 52, so that the cam 32, the connecting rod and the pressure relief rod 52 form a crank-connecting rod mechanism to convert the rotational motion of the cam 32 into the linear motion of the pressure relief rod 52.

[0079] In other embodiments, the first driving surface 322 and the second driving surface 323 can be disposed on the bottom wall of the cam 32. Specifically, a protrusion extending in a circumferential direction can be disposed on the bottom wall of the cam 32. The protrusion includes a first region extending in a circumferential direction and a second region connected to the remaining regions. The height of the first region gradually increases, and the height of the second region is consistent, so that the first driving surface 322 is formed on the first region and the second driving surface 323 is formed on the second region, so that when the cam 32 rotates, the protrusion pushes the pressure relief rod 52 to move axially.

[0080] In other embodiments, the rotating member 53 may be omitted.

[0081] In other embodiments, the first stop pin 35 and the first elastic element 36 can be omitted. A pawl can be hinged to the outer wall of the rotating shaft 31, with the pawl extending in an arc shape. A spring is provided between the pawl and the outer wall of the rotating shaft 31. When the rotating shaft 31 reverses, the pawl is engaged in the first stop groove 311 under the force of the spring and engages with the first stop step 312 circumferentially. Of course, the pawl can also be provided on the cam 32, and the first stop groove 311 can be provided on the rotating shaft 31.

[0082] In other embodiments, the second stop pin 37 and the second elastic member 38 can be omitted. A pawl can be hinged to the inner wall of the pressure block 33, extending in an arc shape. A spring is provided between the pawl and the inner wall of the pressure block 33. When the rotating shaft 31 rotates forward, the pawl is engaged in the second stop groove 324 under the force of the spring to stop in a circumferential manner with the second stop step 325. Of course, the pawl can also be provided on the rotating shaft 31, and the second stop groove 324 can be provided on the pressure block 33.

[0083] In other embodiments, the pressure boosting surface 34 can be omitted, and the pressure boosting block 33 and the piston rod 42 can be connected by a connecting rod, so that the pressure boosting block 33 and the piston rod 42 form a crank mechanism, so that the rotating pressure boosting block 33 can drive the piston rod 42 to move axially.

[0084] In other embodiments, the steering knuckle 43 may be omitted.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A plunger pump, characterized in that, The pump includes a motor (2), a pump body (1), a shaft assembly (3), a piston assembly (4), and a pressure relief assembly (5). The piston assembly (4) and the pressure relief assembly (5) are installed inside the pump body (1). The shaft assembly (3) includes a shaft (31), a cam (32), and a pressure boosting block (33). The cam (32) and the pressure boosting block (33) are sleeved on the shaft (31). The output shaft of the motor (2) is connected to the shaft (31) to drive the shaft (31) to rotate clockwise around its own axis. In the reverse direction, the plunger pump has a boosting position and a depressurization position. In the boosting position, the motor (2) drives the rotating shaft (31) to rotate forward, the cam (32) is released from circumferential locking with the rotating shaft (31), and the boosting block (33) is circumferentially locked on the rotating shaft (31). In the depressurization position, the motor (2) drives the rotating shaft (31) to rotate backward, the cam (32) is circumferentially locked on the rotating shaft (31), and the boosting block (33) is released from circumferential locking with the rotating shaft (31). The piston assembly (4) includes a piston cylinder (41) and a piston rod (42). One end of the piston rod (42) extends out of the piston cylinder (41) and contacts the pressure block (33). When the shaft (31) rotates forward, the pressure block (33) drives the piston rod (42) to reciprocate along the axial direction. The pressure relief assembly (5) includes a pressure relief cylinder (51), a pressure relief rod (52), and a reset member (54). The pressure relief rod (52) and the reset member (54) are installed inside the pressure relief cylinder (51). The pressure relief cylinder (51) is provided with a pressure relief port, which is used to relieve pressure from the piston cylinder (41). In the pressurization position, the pressure relief rod (52) blocks the pressure relief port. When the rotating shaft (31) reverses, the cam (32) drives the pressure relief rod (52) to move axially against the elastic force of the reset member (54) to open the pressure relief port. The cam (32) has a first driving surface (322) and a second driving surface (323). The first driving surface (322) extends along the circumferential direction of the cam (32) and is inclined toward the pressure relief rod (52). The circumferential extension angle of the first driving surface (322) is less than 360°. The second driving surface (323) is perpendicular to the moving direction of the pressure relief rod (52). The side of the first driving surface (322) near the pressure relief rod (52) is connected to the second driving surface (323) to guide the pressure relief rod (52) to contact the second driving surface (323) when the cam (32) rotates. A notch (321) is provided on the outer peripheral wall of the cam (32). The notch (321) passes through one axial end of the cam (32) near the pressure relief rod (52). In the pressurization position, the end of the pressure relief rod (52) extends into the notch (321). The notch (321) forms the first driving surface (322) on the side wall of the rotating shaft (31) in the reverse direction. The end face of the cam (32) near the pressure relief rod (52) forms the second driving surface (323).

2. The plunger pump according to claim 1, characterized in that, The pressure relief assembly (5) also includes a rotating component (53), which is rotatably mounted on the pressure relief rod (52). The rotation axis of the rotating component (53) is perpendicular to the rotation axis of the cam (32). The outer peripheral wall of the rotating component (53) contacts and engages with the first driving surface (322) and the second driving surface (323) when the cam (32) rotates.

3. The plunger pump according to claim 1, characterized in that, It also includes a first stop pin (35) and a first elastic element (36). The outer wall of the rotating shaft (31) is provided with a first mounting hole extending radially. One end of the first stop pin (35) is inserted into the first mounting hole, and the other end abuts against the inner peripheral wall of the cam (32). The two ends of the first elastic element (36) abut against the cam (32) and the first stop pin (35) respectively. The inner peripheral wall of the cam (32) is provided with an arc-shaped first stop groove (311). The radius of the first stop groove (311) gradually increases in the reverse direction of the rotating shaft (31). The first stop groove (311) smoothly transitions with the inner wall of the cam (32) on one side of the rotating shaft (31) in the forward rotation direction, and forms a first stop step (312) between the other side and the inner wall of the cam (32). The first stop step (312) is used to stop and cooperate with the first stop pin (35) in the circumferential direction when the rotating shaft (31) reverses.

4. The plunger pump according to claim 3, characterized in that, Multiple first stop grooves (311) are provided, and each first stop groove (311) is distributed along the circumferential direction of the cam (32).

5. The plunger pump according to any one of claims 1 to 4, characterized in that, It also includes a second stop pin (37) and a second elastic member (38). The pressure block (33) is provided with a second mounting hole extending radially. One end of the second stop pin (37) is inserted into the second mounting hole, and the other end abuts against the outer wall of the rotating shaft (31). The two ends of the second elastic member (38) abut against the pressure block (33) and the second stop pin (37) respectively. An arc-shaped second stop groove (324) is provided on the outer wall of the rotating shaft (31). The radius of the second stop groove (324) gradually increases along the forward rotation direction of the rotating shaft (31). The second stop groove (324) smoothly transitions with the outer wall of the rotating shaft (31) on one side in the forward rotation direction of the rotating shaft (31), and forms a second stop step (325) between the other side and the outer wall of the rotating shaft (31). The second stop step (325) is used to stop and cooperate with the second stop pin (37) in the circumferential direction when the rotating shaft (31) rotates forward.

6. The plunger pump according to any one of claims 1 to 4, characterized in that, The booster block (33) has a booster surface (34), which has a non-zero angle with the axis of the piston rod (42). When the booster block (33) rotates, the booster surface (34) pushes the piston rod (42) to reciprocate along its axis.

7. The plunger pump according to claim 6, characterized in that, A steering knuckle (43) is installed at one end of the piston rod (42) that extends out of the piston cylinder (41). The steering knuckle (43) is ball-jointed to the piston rod (42). The side of the steering knuckle (43) facing the pressure surface (34) has an inclined surface that is adapted to the pressure surface (34).

8. The plunger pump according to any one of claims 1 to 4, characterized in that, It also includes a rubber sealing ring (7) and a plurality of metal sealing rings (6), the rubber sealing ring (7) and the metal sealing rings (6) being sleeved on one end of the piston rod (42) that extends into the piston cylinder (41) so that the piston rod (42) and the piston cylinder (41) are sealed together. In the axial direction of the piston rod (42), the rubber sealing ring (7) is installed between the two metal sealing rings (6).

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