A cam-driven pump

Abstract

This utility model relates to the field of transmission pump technology and discloses a cam-driven pump. The cam-driven pump includes a plunger assembly and a first drive assembly. The plunger assembly has a plunger rod that reciprocates along a first direction. The first drive assembly includes a first drive member and a cam. The first drive member is driven and connected to the cam, and can drive the cam to rotate. The end of the plunger rod is slidably connected to the outer contour of the cam. The outer contour of the cam includes a working section and a return section connected end-to-end. The working section drives the plunger rod to move away from the cam, and the return section drives the plunger rod to move closer to the cam. The arc of the working section is greater than the arc of the return section. Because the arc of the working section is greater than the arc of the return section, the duty cycle of the cam is greater than 50%, improving energy utilization. This utility model, through cam transmission, converts the rotational drive of the first drive member into the linear reciprocating motion of the plunger rod, and improves the duty cycle of the working operation.

Description

Technical Field

[0001] This utility model relates to the field of transmission pump technology, and in particular to a cam-driven pump. Background Technology

[0002] In industry and many specific fields, plunger pumps are key fluid transport and pressurization equipment. Their common working principle is to use a crank-slider mechanism to convert the rotary motion of the motor into the linear reciprocating motion of the plunger, and then use the synchronous opening and closing of two one-way valves to achieve the pressurization and pumping of liquid.

[0003] However, traditional plunger pumps have significant drawbacks. The crank-slider mechanism causes the plunger's linear velocity to vary sinusoidally, and when the plunger retracts, it is in the pressure chamber's suction range, unable to pump liquid. This results in a theoretically low duty cycle for work, of only 50%, leading to low energy utilization efficiency.

[0004] Therefore, there is an urgent need for a cam-driven pump to solve the aforementioned problems. Utility Model Content

[0005] Based on the above, the purpose of this utility model is to provide a cam-driven pump that converts the rotational drive of the first driving member into the linear reciprocating motion of the piston rod through cam transmission, and improves the duty cycle of work.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A cam-driven pump, comprising:

[0008] A plunger assembly having a plunger rod that reciprocates in a first direction;

[0009] A first drive assembly includes a first drive member and a cam. The first drive member is drivably connected to the cam and is capable of driving the cam to rotate. The end of the plunger rod is slidably connected to the outer contour of the cam. The outer contour of the cam includes a working section and a reset section connected end to end. The working section is used to drive the plunger rod to move away from the cam, and the reset section is used to drive the plunger rod to move closer to the cam. The arc of the working section is greater than the arc of the reset section.

[0010] As a preferred technical solution for a cam-driven pump, the reset section includes a return section AC, the first end of which is connected to the last end of the working section. The distance from the last end of the return section AC to the rotation axis of the cam is the same as the distance from the first end of the working section to the rotation axis of the cam.

[0011] As a preferred technical solution for a cam-driven pump, the reset section further includes a waiting section CB. The outline of the waiting section CB is at a constant distance from the rotation axis, and one end of the waiting section CB is connected to the tail end of the return section AC, while the other end is connected to the beginning end of the work section.

[0012] As a preferred technical solution for a cam-driven pump, the return segment AC is concave in shape, the tail end of the return segment AC is tangent to the head end of the waiting segment CB, and the tail end of the waiting segment CB is tangent to the head end of the working segment.

[0013] As a preferred technical solution for a cam-driven pump, the ratio of the arc of the return segment AC to the arc of the waiting segment CB is in the range of 0.5-1.

[0014] As a preferred technical solution for a cam-driven pump, the working section is distributed in an Archimedean spiral pattern.

[0015] As a preferred technical solution for a cam-driven pump, a roller is provided at one end of the plunger rod near the cam, and the roller is rotatably connected to the outer contour of the cam.

[0016] As a preferred technical solution for a cam-driven pump, the plunger assembly further includes a housing, an inlet check valve, and an outlet check valve. The housing is provided with a pressurizing cavity extending along the first direction. The end of the plunger rod opposite to the cam is sealed and slidably connected to the inner wall of the pressurizing cavity. The pressurizing cavity is provided with an inlet and an outlet. The inlet check valve is located at the inlet, and the outlet check valve is located at the outlet.

[0017] As a preferred technical solution for a cam-driven pump, the plunger assembly further includes an elastic element disposed between the plunger rod and the housing, the elastic force of which can drive the plunger rod to conform to the outer contour of the cam.

[0018] As a preferred technical solution of a cam-driven pump, the cam-driven pump further includes a second drive assembly. The cam is tapered along the extension direction of the rotation axis. The second drive assembly is driven and connected to the first drive assembly. The second drive assembly is used to drive the first drive assembly to reciprocate along the direction of the rotation axis.

[0019] As a preferred technical solution for a cam-driven pump, the outer wall of the roller is tapered, and the outer wall of the roller has the same taper as the outer wall of the cam.

[0020] As a preferred technical solution for a cam-driven pump, the first drive assembly further includes a drive seat, the drive seat is provided with a groove, the cam is connected to the bottom of the groove, a guide groove with the same shape as the outer contour is formed between the outer contour of the cam and the inner wall of the groove, and the roller is rotatably connected to the guide groove.

[0021] The beneficial effects of this utility model are as follows:

[0022] This invention provides a cam-driven pump. During operation, a first driving element drives the cam to rotate. The working section, from point B to point A, sequentially slides against the end of a plunger rod. The plunger rod gradually moves away from the cam's rotation axis along a first direction and reaches the pump position. The plunger assembly pumps fluid through the plunger rod. Then, the reset section, from point A to point B, sequentially slides against the end of the plunger rod. The plunger rod gradually moves closer to the cam's rotation axis along the first direction and reaches the suction position. The plunger assembly draws fluid through the plunger rod. Then, the working section of the cam again slides against the end of the plunger rod, achieving a reciprocating cyclic motion of the plunger rod along the first direction. Because the arc of the working section is greater than that of the reset section, the duty cycle of the cam during one revolution is greater than 50%, improving energy utilization. This invention, through cam transmission, converts the rotational drive of the first driving element into the linear reciprocating motion of the plunger rod and improves the duty cycle of the working section. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the cam-driven pump provided in Embodiment 1 of this utility model;

[0025] Figure 2 This is a schematic diagram of the cam structure provided in Embodiment 1 of this utility model;

[0026] Figure 3 This is a cross-sectional view of the cam-driven pump provided in Embodiment 1 of this utility model;

[0027] Figure 4 This is a comparison diagram of the pumping speed of this utility model and a common crank-slider mechanism;

[0028] Figure 5 This is a comparison diagram of the plunger speed of this utility model and common crank-slider mechanisms;

[0029] Figure 6 This is a schematic diagram of the cam-driven pump provided in Embodiment 2 of this utility model;

[0030] Figure 7 This is a schematic diagram of the cam-driven pump provided in Embodiment 3 of this utility model.

[0031] The markings in the image are as follows:

[0032] 1. Plunger assembly; 11. Plunger rod; 111. Push rod; 1111. Limiting protrusion; 112. Plunger; 113. Locking sleeve; 114. Sealing ring; 12. Housing; 121. Pressurizing chamber; 122. Inlet; 123. Outlet; 13. Inlet check valve; 14. Outlet check valve; 15. Roller; 16. Elastic element;

[0033] 2. First drive assembly; 21. First drive component; 22. First fixing plate; 23. Drive base; 231. Guide groove;

[0034] 3. Cam; 31. Working section; 32. Reset section; 321. Return section AC; 322. Waiting section CB;

[0035] 4. Second drive assembly; 41. Second fixing plate; 42. Second drive component; 43. Guide rail; 44. Connecting plate; 45. Lead screw; 46. Lead screw nut. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0037] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0038] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0040] Example 1

[0041] like Figure 1 and Figure 2 As shown, this embodiment provides a cam-driven pump, which includes a plunger assembly 1 and a first drive assembly 2. The plunger assembly 1 is provided with a plunger rod 11 that reciprocates along a first direction. The first drive assembly 2 includes a first drive member 21 and a cam 3. The first drive member 21 is driven and connected to the cam 3 and can drive the cam 3 to rotate. The end of the plunger rod 11 is slidably connected to the outer contour of the cam 3. The outer contour of the cam 3 includes a working section 31 and a reset section 32 connected end to end. The working section 31 is used to drive the plunger rod 11 to move away from the cam 3, and the reset section 32 is used to drive the plunger rod 11 to move closer to the cam 3. The curvature of the working section 31 is greater than the curvature of the reset section 32.

[0042] During operation, the first driving component 21 drives the cam 3 to rotate. The working section 31, from point B to point A, sequentially slides against the end of the plunger rod 11. The plunger rod 11 gradually moves away from the rotation axis of the cam 3 along the first direction and reaches the pump position. The plunger assembly 1 pumps liquid through the plunger rod 11. Then, the reset section 32AB, from point A to point B, sequentially slides against the end of the plunger rod 11. The plunger rod 11 gradually moves closer to the rotation axis of the cam 3 along the first direction and reaches the suction position. The plunger assembly 1 suctions liquid through the plunger rod 11. Then, the working section 31 of the cam 3 slides against the end of the plunger rod 11 again, realizing the reciprocating cyclic motion of the plunger rod 11 along the first direction. Because the arc of the working section 31 is greater than the arc of the reset section 32AB, the duty cycle of the cam 3 during one rotation is greater than 50%, improving energy utilization. This invention uses cam 3 to drive the rotation of the first driving member 21 into the linear reciprocating motion of the plunger rod 11, and improves the duty cycle of the work.

[0043] Furthermore, the reset section 32 includes a return section AC321, the first end of which is connected to the last end of the working section 31. The distance between the last end of the return section AC321 and the rotation axis of the cam 3 is the same as the distance between the first end of the working section 31 and the rotation axis of the cam 3. The contour of the working section 31 gradually moves away from the rotation axis of the cam 3, while the contour of the return section AC321 gradually moves closer to the rotation axis of the cam 3. When the first end A to the last end C of the return section AC321 slides sequentially against the end of the plunger rod 11, the plunger rod 11 moves from the pump level to the suction position.

[0044] More preferably, the reset section 32 further includes a waiting section CB322. The distance between the outline of the waiting section CB322 and the rotation axis remains unchanged, and one end of the waiting section CB322 is connected to the tail end of the return section AC321, while the other end is connected to the head end of the work section 31. When the end of the plunger rod 11 is slidably connected to the outer contour of the reset section 32, it first passes through the return section AC321, realizing the rapid movement of the plunger rod 11 to the suction position and increasing the reset speed. At this time, the suction pressure in the pressurization chamber 121 of the plunger assembly 1 is relatively large, realizing the rapid suction of liquid and increasing the suction speed. When the end of the plunger rod 11 passes through the waiting section CB322, the position of the plunger rod 11 remains unchanged, so that the plunger assembly 1 maintains the suction state under a large suction pressure, and rapidly suctions more liquid.

[0045] More preferably, the return segment AC321 is concave in shape, with its tail end tangent to the head end of the waiting segment CB322, and the tail end of the waiting segment CB322 tangent to the head end of the working segment 31. When the plunger rod 11 is slidably connected to the concave return segment AC321, the plunger rod 11 can quickly return to its original position. Since the tail end of the return segment AC321 is tangent to the head end of the waiting segment CB322, and the tail end of the waiting segment CB322 is tangent to the head end of the working segment 31, the smoothness of the plunger rod 11's movement is improved when the contact area between the plunger rod 11 and the cam 3 transitions from the return segment AC321 to the waiting segment CB322, and when the waiting segment CB322 transitions to the working segment 31.

[0046] Preferably, the ratio of the arc of the return segment AC321 to the arc of the waiting segment CB322 is in the range of 0.5-1. In this embodiment, the ratio of the arc of the return segment AC321 to the arc of the waiting segment CB322 can be 0.5, 0.6, 0.7, 0.8, 0.9, or 1, etc. The ratio of the arc of the return segment AC321 to the arc of the waiting segment CB322 should not be too small. If the return segment AC321 is too small, although it can increase the reset speed of the plunger rod 11, if the reset speed is too large, it will increase the impact force of the plunger rod 11 on the cam 3. The ratio of the arc of the return segment AC321 to the arc of the waiting segment CB322 should not be too large. If the return segment AC321 is too large, the plunger rod 11 resets slowly, reducing the suction pressure and the time the plunger rod 11 is in the suction position, thus reducing the volume of liquid pumped each time, which cannot meet the requirements.

[0047] In existing technologies, the pump body using a crank-slider structure does not move at a constant speed during pumping, resulting in significant fluctuations in the output liquid flow rate. In this embodiment, the working section 31 is distributed in an Archimedean spiral pattern, with the radius of the curve of the working section 31 steadily increasing as the angle changes. When the working section 31 drives the plunger rod 11 from the suction position to the pump liquid level, the plunger rod 11 moves at a constant speed, thereby achieving a more stable liquid booster pumping flow rate.

[0048] In this embodiment, the curve coordinate equation of the work section 31 is:

[0049] X(θ) = (R0 + h*θ)*cos(θ);

[0050] y(θ)=(R0+h*θ)*sin(θ);

[0051] Where θ is the radian of clockwise rotation of cam 3, in rad, and the interval of the working segment 31 after conversion to angle is a°. R0 is the initial radius of the working segment 31, and h is the radius increment of the working segment 31 (the amount of radius increase per radian). It should be noted that the distribution equation of the Archimedean spiral is existing technology.

[0052] Furthermore, such as Figure 3 As shown, the plunger assembly 1 also includes a housing 12, an inlet check valve 13, and an outlet check valve 14. The housing 12 is provided with a pressurizing chamber 121 extending along a first direction. The end of the plunger rod 11 facing away from the cam 3 is sealed and slidably connected to the inner wall of the pressurizing chamber 121. The pressurizing chamber 121 is provided with an inlet 122 and an outlet 123. The inlet check valve 13 is located at the inlet 122, and the outlet check valve 14 is located at the outlet 123. During the process of the plunger rod 11 moving to the suction position, liquid enters the pressurizing chamber 121 through the inlet 122 and the inlet check valve 13. During the process of the plunger rod 11 moving to the pump level, the liquid in the pressurizing chamber 121 is discharged through the outlet check valve 14 and the outlet 123, thus realizing the pumping of liquid.

[0053] In this embodiment, a roller 15 is provided at one end of the plunger rod 11 near the cam 3. The roller 15 is rolled and connected to the outer contour of the cam 3, which reduces the friction between the plunger rod 11 and the cam 3, reduces mutual wear between the two, and facilitates relative movement between the two.

[0054] In this embodiment, the plunger rod 11 includes a push rod 111, a plunger 112, and a locking sleeve 113. The locking sleeve 113 fixes the plunger 112 to one end of the push rod 111 located in the pressurizing chamber 121. The plunger 112 is slidably connected to the inner wall of the pressurizing chamber 121, and the other end of the push rod 111 is slidably connected to the outer contour of the cam 3. When the push rod 111 moves in the first direction, the plunger 112 moves synchronously. The sealing ring 114 is disposed on the outer wall of the plunger 112, realizing the seal between the plunger 112 and the pressurizing chamber 121. With the cooperation of the inlet check valve 13 and the outlet check valve 14, water is drawn in from the inlet 122 and pumped out from the outlet 123 after pressurization.

[0055] Furthermore, the plunger assembly 1 also includes an elastic element 16, which is disposed between the plunger rod 11 and the housing 12. The elastic force of the elastic element 16 can drive the plunger rod 11 to conform to the outer contour of the cam 3. In this embodiment, the elastic element 16 is a spring, and the outer wall of the plunger rod 11 is provided with a limiting protrusion 1111. The spring is sleeved on the plunger rod 11, with one end abutting against the limiting protrusion 1111 and the other end abutting against the outer wall of the housing 12. The spring applies an elastic force to the plunger rod 11 so that the end of the plunger rod 11 always conforms to the outer contour of the cam 3.

[0056] It should be noted that when the cam-driven pump needs to output different flow rates, the rotational speed of cam 3 is adjusted according to the requirements. However, the elastic force of the elastic element 16 does not change with the rotational speed of cam 3. Therefore, it can be considered that the time for the elastic element 16 to push the plunger rod 11 back from the far end is fixed. However, the contact time between the return section 32 of cam 3 and the plunger rod 11 varies. At high speeds, after the plunger rod 11 returns to its original position, cam 3 has already rotated past the return section 32 and directly enters the working section 31. This will cause the reciprocating stroke of the plunger rod 11 to be reduced, the pumped volume to be reduced, and it will be detrimental to the flow rate control accuracy. Therefore, this embodiment sets a waiting section CB322 to wait for the plunger rod 11 to return to its original position, ensuring that the plunger rod 11 has returned to its original position before entering the working section 31, and ensuring that the reciprocating stroke of the plunger rod 11 meets the requirements.

[0057] In this embodiment, the first drive assembly 2 further includes a first fixing plate 22, the first drive component 21 is a motor, the first fixing plate 22 is connected to the housing 12, the motor is fixed on the first fixing plate 22, the first fixing plate 22 is provided with a through hole, and the output shaft of the motor passes through the through hole and is connected to the cam 3.

[0058] This embodiment also provides the working principle of the cam-driven pump. The push rod 111 slides back and forth in the first direction under the limit of the pressurizing chamber 121. The elastic element 16 drives the roller 15 of the push rod 111 to always fit against the outer contour of the cam 3. When the cam 3 rotates clockwise under the drive of the motor, when the cam 3 rotates to the working section 31 and contacts the plunger rod 11, the distance between the edge of the cam 3 and the rotation axis begins to increase, driving the plunger rod 11 to move from the suction position to the pump liquid position. When the cam 3 rotates to the reset section 32 and contacts the plunger rod 11, the distance between the edge of the cam 3 and the rotation axis begins to decrease, and the push rod 111 is pushed back under the action of the elastic element 16, maintaining contact with the reset section 32 of the cam 3. The reset section 32 of the cam 3 and the elastic element 16 cooperate to drive the plunger rod 11 to move from the pump liquid position to the suction position.

[0059] like Figure 4 As shown, when the piston rod 11 travels the same distance, the booster chamber 121 has the same volume, and the cam 3 rotates at the same speed, the pumping speed of this embodiment is compared with that of a common crank-slider mechanism. The work done in this application has a higher duty cycle. Figure 5 As shown, when the piston rod 11 moves at the same distance, the pressurizing chamber 121 has the same volume, and the cam 3 rotates at the same speed, the piston speed in this embodiment is compared with that of a common crank-slider mechanism. The piston speed in this embodiment is more stable and the return time is shorter.

[0060] Example 2

[0061] like Figure 6As shown, this embodiment provides a cam-driven pump. The structure of the cam-driven pump provided in this embodiment is basically the same as that in Embodiment 1. This embodiment will not repeat the structure that is the same as that in Embodiment 1.

[0062] In the prior art, when the cam 3 rotates at high speed, the return speed of the plunger rod 11 is too fast, and the short liquid inlet time of the pressurization chamber 121 may cause air blockage. To solve the above problems, in this embodiment, the cam-driven pump also includes a second drive assembly 4. The cam 3 is tapered along the extension direction of the rotation axis. The second drive assembly 4 is driven and connected to the first drive assembly 2. The second drive assembly 4 is used to drive the first drive assembly 2 to reciprocate along the direction of the rotation axis.

[0063] In this configuration, when the second drive assembly 4 drives the first drive assembly 2 to reciprocate along the rotation axis, the position of the plunger rod 11 remains unchanged. Different outer walls of the cam 3, extending along the rotation axis, contact the plunger rod 11. When the outer wall of the cam 3 with a larger cross-sectional profile contacts the plunger rod 11, the stroke of the plunger rod 11 is reduced; conversely, when the outer wall of the cam 3 with a smaller cross-sectional profile contacts the plunger rod 11, the stroke of the plunger rod 11 is increased, thus achieving adjustment of the plunger rod 11's stroke. By adjusting the plunger rod 11's stroke, when a small flow rate is required, the cam 3's rotation speed can be reduced while simultaneously decreasing the plunger rod 11's stroke; when a large flow rate is required, both the cam 3's rotation speed and the plunger rod 11's stroke can be increased.

[0064] Preferably, the outer wall of the roller 15 is tapered, and the outer wall of the roller 15 has the same taper as the outer wall of the cam 3, so that the outer wall of the roller 15 can fit against the outer wall of the cam 3, thereby improving the stability of the connection between the two.

[0065] In this embodiment, the second drive assembly 4 includes a second fixed plate 41 and a second drive member 42. The second fixed plate 41 is connected to the housing 12 of the plunger assembly 1. The second drive member 42 is fixed to the second fixed plate 41 and is driven to the first drive member 21. The second drive member 42 is used to drive the first drive member 21 to move along the rotation axis of the cam 3.

[0066] Specifically, the second drive assembly 4 further includes a guide rail 43, a connecting plate 44, a lead screw 45, and a lead screw nut 46. The guide rail 43 extends along the rotation axis of the cam 3 and is fixed to the second fixed plate 41. The connecting plate 44 is slidably connected to the guide rail 43. The second drive member 42 is a motor, the output end of which is connected to the lead screw 45, and the lead screw 45 is threadedly connected to the lead screw nut 46. When the motor output end rotates, it can thread-drive the lead screw nut 46, the connecting plate 44, the first drive member 21, and the cam 3 to move along the rotation axis of the cam 3, thereby adjusting the stroke of the plunger rod 11. In other embodiments, the second drive member 42 can also be a cylinder.

[0067] Example 3

[0068] like Figure 7 As shown, this embodiment provides a cam-driven pump. The structure of the cam-driven pump provided in this embodiment is basically the same as that in Embodiment 1. This embodiment will not repeat the structure that is the same as that in Embodiment 1.

[0069] In this embodiment, the first drive assembly 2 further includes a drive seat 23, which has a groove. A cam 3 is connected to the bottom of the groove, and a guide groove 231 with the same shape as the outer contour is formed between the outer contour of the cam 3 and the inner wall of the groove. A roller 15 is rotatably connected to the guide groove 231. By setting the guide groove 231, the elastic element 16 can be eliminated, and the advancement and return of the plunger rod 11 can be driven by the guide groove 231, making the entire mechanism operate more smoothly.

[0070] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A cam-driven pump, characterized in that, include: A plunger assembly (1) is provided with a plunger rod (11) that reciprocates in a first direction; The first drive assembly (2) includes a first drive member (21) and a cam (3). The first drive member (21) is driven to the cam (3) and can drive the cam (3) to rotate. The end of the plunger rod (11) is slidably connected to the outer contour of the cam (3). The outer contour of the cam (3) includes a working section (31) and a reset section (32) connected end to end. The working section (31) is used to drive the plunger rod (11) to move away from the cam (3). The reset section (32) is used to drive the plunger rod (11) to move closer to the cam (3). The arc of the working section (31) is greater than the arc of the reset section (32).

2. The cam-driven pump according to claim 1, characterized in that, The reset section (32) includes a return section AC (321), the beginning of which is connected to the end of the work section (31). The distance between the end of the return section AC (321) and the rotation axis of the cam (3) is the same as the distance between the beginning of the work section (31) and the rotation axis of the cam (3).

3. The cam-driven pump according to claim 2, characterized in that, The reset segment (32) also includes a waiting segment CB (322), the outline of which is at a constant distance from the rotation axis, and one end of the waiting segment CB (322) is connected to the tail end of the return segment AC (321), and the other end is connected to the head end of the work segment (31).

4. The cam-driven pump according to claim 3, characterized in that, The regression segment AC (321) is concave in shape, and the tail end of the regression segment AC (321) is tangent to the head end of the waiting segment CB (322), and the tail end of the waiting segment CB (322) is tangent to the head end of the work segment (31).

5. The cam-driven pump according to claim 3, characterized in that, The ratio of the radian of the regression segment AC (321) to the radian of the waiting segment CB (322) is in the range of 0.5-1.

6. The cam-driven pump according to claim 1, characterized in that, The working section (31) is distributed in an Archimedean spiral pattern.

7. The cam-driven pump according to claim 1, characterized in that, A roller (15) is provided at one end of the plunger rod (11) near the cam (3), and the roller (15) is tactilely connected to the outer contour of the cam (3).

8. The cam-driven pump according to claim 1, characterized in that, The plunger assembly (1) further includes a housing (12), an inlet check valve (13), and an outlet check valve (14). The housing (12) is provided with a pressurizing chamber (121) extending along the first direction. The plunger rod (11) is sealed and slidably connected to the inner wall of the pressurizing chamber (121) at the end away from the cam (3). The pressurizing chamber (121) is provided with an inlet (122) and an outlet (123). The inlet check valve (13) is located at the inlet (122), and the outlet check valve (14) is located at the outlet (123).

9. The cam-driven pump according to claim 8, characterized in that, The plunger assembly (1) further includes an elastic element (16), which is disposed between the plunger rod (11) and the housing (12). The elastic force of the elastic element (16) can drive the plunger rod (11) to conform to the outer contour of the cam (3).

10. The cam-driven pump according to claim 7, characterized in that, The cam-driven pump further includes a second drive assembly (4), the cam (3) is tapered along the extension direction of the rotation axis, the second drive assembly (4) is driven and connected to the first drive assembly (2), and the second drive assembly (4) is used to drive the first drive assembly (2) to reciprocate along the direction of the rotation axis.

11. The cam-driven pump according to claim 10, characterized in that, The outer wall of the roller (15) is tapered, and the outer wall of the roller (15) has the same taper as the outer wall of the cam (3).

12. The cam-driven pump according to claim 7, characterized in that, The first drive assembly (2) further includes a drive seat (23), the drive seat (23) is provided with a groove, the cam (3) is connected to the bottom of the groove, a guide groove (231) with the same shape as the outer contour is formed between the outer contour of the cam (3) and the inner wall of the groove, and the roller (15) is rotatably connected to the guide groove (231).

Images