Structural design method of cam assembly, cam assembly, transmission device and electronic infusion pump
By designing and adjusting the timing relationship and structure of the cam assembly, the problem of unclear cam assembly movement timing was solved, the infusion accuracy and efficiency of the electronic infusion pump were improved, and the accuracy and safety of the infusion process were ensured.
Patent Information
- Application Number
- CN202510910783.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-02
- Publication Date
- 2025-10-10
AI Technical Summary
The existing cam assembly has unclear movement timing, resulting in inaccurate infusion flow and accuracy, and unable to promptly warn of pipeline blockage.
By determining the set timing relationship and base circle of the first, second, and third cam groups, an initial cam structure that meets the standard working process is designed. After verification through simulation software, the cam structure is adjusted to match the infusion requirements to ensure that the cam assembly accurately matches the infusion requirements during movement.
The detailed actions during aspiration and discharge have been optimized to improve the accuracy and efficiency of infusion, ensure that the electronic infusion pump forms sufficient vacuum during aspiration and positive pressure during discharge, and promptly alarm for pipeline blockage.
Smart Images
Figure CN120764092A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electronic infusion pumps, and in particular relates to a structural design method of a cam assembly, a cam assembly, a transmission device and an electronic infusion pump. Background Art
[0002] In the prior art, electronic infusion pumps precisely control the flow rate through an internal transmission device to infuse the liquid in the liquid storage bag into the patient. The transmission device of an electronic infusion pump is generally a peristaltic transmission or an extrusion transmission. Compared with the two, the extrusion transmission device can more conveniently control the infusion accuracy. Electronic infusion pumps generally rely on a cam assembly to achieve extrusion infusion. The timing control logic of the existing cam assembly is unclear and cannot accurately complete the following functions: when aspirating liquid, a sufficiently large vacuum is formed in the tube to draw liquid, while not discharging liquid into the infusion tube close to the human body; when discharging liquid, the internal valve is closed to prevent the liquid from flowing back into the liquid storage bag; when the infusion pipeline is blocked, the alarm cannot be issued in time. It can be seen that the movement timing of the cam assembly affects the infusion flow rate and accuracy.
[0003] A new structural design method of a cam assembly is needed to solve the above problems. Summary of the Invention
[0004] The purpose of the present invention is to provide a structural design method of a cam assembly, which is used to solve the technical problem in the prior art that the cam assembly has low rotation accuracy and causes low infusion accuracy.
[0005] Another object of the present invention is to provide a cam assembly.
[0006] Another object of the present invention is to provide a transmission device.
[0007] Another object of the present invention is to provide an electronic infusion pump.
[0008] The technical solution of the present invention to solve the technical problem is: A structural design method for a cam assembly comprises the following steps: S1: According to the standard working process requirements of the cam assembly, determine the setting timing relationship of the first distal repose angle, the first return angle, and the first push angle in the first cam group, the second distal repose angle, the second return angle, the second proximal repose angle, and the second push angle in the second cam group, and the third distal repose angle, the third return angle, and the third push angle in the third cam group, wherein the third distal repose angle is greater than the sum of the second return angle and the second proximal repose angle, and the sum of the second return angle and the second proximal repose angle is greater than the sum of the first return angle and the first push angle; the first distal repose angle is greater than the sum of the second distal repose angle and the second push angle, and the sum of the second distal repose angle and the second push angle is greater than the sum of the third return angle and the third push angle, so that during the movement of the designed cam assembly, the second distal repose angle enters the working area later than the first distal repose angle; S2: calculating the base circle corresponding to the first cam set, the second cam set and the third cam set according to the first return angle, the first push angle, the second near rest angle, the third return angle and the third push angle; S3: determining the initial cam structure of the first cam set, the second cam set and the third cam set according to the set timing relationship and the base circle corresponding to the first cam set, the second cam set and the third cam set; S4: simulating the initial cam structure of the first cam set, the second cam set and the third cam set by using simulation software to obtain the motion timing relationship of the cam assembly, judging whether the motion timing relationship is consistent with the set timing relationship in step S1, if yes, outputting the cam structure of the first cam set, the second cam set and the third cam set; if no, executing step S5; S5: adjusting the cam structure of the first cam set, the second cam set and the third cam set, and taking the adjusted cam structure as the initial cam structure of the first cam set, the second cam set and the third cam set, and executing step S4. Preferably, the specific steps of step S2 are as follows: taking the transition arc radius between the first return angle and the first push angle as the base circle radius of the first cam set; taking the radius of the second near rest angle as the base circle radius of the second cam set; and taking the transition arc radius between the third return angle and the third push angle as the base circle radius of the third cam set, to obtain the base circle corresponding to the first cam set, the second cam set and the third cam set.
[0009] Preferably, step S5 is specifically as follows: adjusting the cam structure of the first cam set, the second cam set and the third cam set according to the standard working process requirement of the cam assembly, so that the cam structure of the first cam set, the second cam set and the third cam set corresponds to the set timing relationship, taking the adjusted cam structure as the initial cam structure of the first cam set, the second cam set and the third cam set, and executing step S4.
[0010] A cam assembly comprises: a first cam group, a second cam group, and a third cam group, the first cam group being used to drive the first valve member to move, the second cam group being used to drive the extrusion member to move, and the third cam group being used to drive the second valve member to move, the first cam group being used to set a cam structure according to a first distal repose angle, a first return angle, and a first push angle, the second cam group being used to set a cam structure according to a second distal repose angle, a second return angle, a second proximal repose angle, and a second push angle, and the third cam group being used to set a cam structure according to a third distal repose angle, a third return angle, and a third push angle; the third distal repose angle is greater than the sum of the second return angle and the second proximal repose angle, and the sum of the second return angle and the second proximal repose angle is greater than the sum of the first return angle and the first push angle; the first distal repose angle is greater than the sum of the second distal repose angle and the second push angle, and the sum of the second distal repose angle and the second push angle is greater than the sum of the third return angle and the third push angle, so that during the movement of the designed cam assembly, the second distal repose angle enters the working area later than the first distal repose angle.
[0011] A transmission device comprises: an electric motor, a coupling, and a cam assembly. The electric motor drives a first cam group, a second cam group, and a third cam group to rotate through the coupling.
[0012] Preferably, it further comprises: a counting sensor, which is arranged above the cam assembly and collects the number of rotations of the cam assembly.
[0013] Preferably, it further comprises: a pressure sensor, which is arranged outside the infusion pipeline to collect the pressure of the infusion pipeline.
[0014] The utility model relates to an electronic infusion pump, which adopts a transmission device.
[0015] The beneficial effects of the present invention are: The timing relationships between the first, second, and third cam groups are determined based on the standard operating process requirements of the cam assembly. The corresponding base circles for the first, second, and third cam groups are calculated based on the first return angle, first thrust angle, second near-rest angle, third return angle, and third thrust angle. The initial cam structures for the first, second, and third cam groups are then determined based on the set timing relationships and their corresponding base circles. Further simulation verification of the initial cam structures ensures that the cam structures accurately match infusion requirements. The near-rest angles in the first and third cam groups are eliminated, allowing the internal valve and extrusion element to immediately open the pipeline when the electronic infusion pump is aspirating; and the extrusion element and external valve to immediately squeeze the pipeline when the internal valve is closed when the electronic infusion pump is discharging. This optimizes the detailed actions during aspiration and discharge, improving infusion accuracy. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is a flow chart of the structural design method of the present application; Figure 2 is a setting timing relationship diagram of the structural design method of the present application; Figure 3 is a motion timing relationship diagram of the structural design method of the present application; Figure 4 is a simulation result modification diagram of the structural design method of the present application; Figure 5 is a structural diagram of the transmission device of the present application; Figure 6 is a structural diagram of the liquid suction stage in the specific working process of the present application; Figure 7 is a structural diagram of the in-valve stage in the specific working process of the present application; Figure 8 is a structural diagram of the liquid discharge stage in the specific working process of the present application; Figure 9 is a structural diagram of the out-valve stage in the specific working process of the present application. DETAILED DESCRIPTION
[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.
[0018] As shown in Figure 1 , the present application discloses a structural design method of a cam assembly, comprising the following steps: S1: as shown in Figure 2 , according to the standard working process requirements of the cam assembly, the setting timing relationship of the first far rest angle, the first return angle, the first push angle in the first cam group, the second far rest angle, the second return angle, the second near rest angle, the second push angle in the second cam group, and the third far rest angle, the third return angle, the third push angle in the third cam group is determined, wherein the third far rest angle is greater than the sum of the second return angle and the second near rest angle, and the sum of the second return angle and the second near rest angle is greater than the sum of the first return angle and the first push angle; the first far rest angle is greater than the sum of the second far rest angle and the second push angle, and the sum of the second far rest angle and the second push angle is greater than the sum of the third return angle and the third push angle, so that the second far rest angle enters the working area later than the first far rest angle in the motion process of the designed cam assembly; S2: Calculate the base circles corresponding to the first cam group, the second cam group, and the third cam group according to the first return angle, the first push angle, the second near-rest angle, the third return angle, and the third push angle; the specific steps are: use the transition arc radius between the first return angle and the first push angle as the base circle radius of the first cam group; use the radius of the second near-rest angle as the base circle radius of the second cam group; use the transition arc radius between the third return angle and the third push angle as the base circle radius of the third cam group; and obtain the base circles corresponding to the first cam group, the second cam group, and the third cam group.
[0019] S3: determining initial cam structures of the first cam group, the second cam group, and the third cam group according to the set timing relationship and the base circles corresponding to the first cam group, the second cam group, and the third cam group; S4: As Figure 3 As shown, the initial cam structures of the first cam group, the second cam group, and the third cam group are simulated using simulation software to obtain the motion timing relationship of the cam components, and it is determined whether the motion timing relationship is consistent with the set timing relationship in step S1. If so, the cam structures of the first cam group, the second cam group, and the third cam group are output; if not, step S5 is executed; S5: Adjust the cam structures of the first, second, and third cam groups, and use the adjusted cam structures as the initial cam structures of the first, second, and third cam groups, and execute step S4. Specifically, adjust the cam structures of the first, second, and third cam groups according to the standard working process requirements of the cam assembly so that the cam structures of the first, second, and third cam groups correspond to the set timing relationship, use the adjusted cam structures as the initial cam structures of the first, second, and third cam groups, and execute step S4.
[0020] The specific simulation software is Creo software, and the specific steps are as follows: 1. Enter the Creo mechanism module and set the motion reference point on the first valve component 5, the extrusion component 6, and the second valve component 7 respectively. Generally, the highest point of contact of the corresponding cam group is selected as the reference point. 2. In the Creo mechanism module, set the cam connection for the cam group and the follower respectively; select the rotation axis and set the parameters of the motor: the drive amount is set to angular velocity, the coefficient A can be set to 10deg / sec, and the graph is set to speed. 3. Run the mechanism analysis and wait for the analysis to complete. 4. Select the "Measurement Results" option, select the motion reference points of the aforementioned follower respectively, and generate the analysis items. Then click the graphic icon in the upper left corner to generate the motion graph of the reference point.
[0021] like Figure 4As shown, when the motion timing relationship is inconsistent with the set timing relationship in step S1, it is assumed that the error in the simulation result occurs at the liquid suction stage of the electronic infusion pump. At this time, the rotation of the third cam set has not entered the third far rest angle, that is, the third cam set is still rotating within the third push angle, while the rotation of the first cam set and the second cam set has entered the return angle. This state will cause the liquid to enter the external infusion pipeline during actual application, resulting in insufficient liquid suction. Therefore, according to the set timing relationship, the cam assembly in the simulation software is modified, and the third far rest angle of the third cam set is advanced compared to the corresponding region of the first cam set and the second cam set in the current state. That is, the outer contour shape of the third cam set is not changed, and a certain angle of the outer contour is rotated counterclockwise, that is, the time when the third cam set enters the third far rest angle is advanced. Similarly, the adjustment method of all cams in other stages of the electronic infusion pump is the same, which will not be described here.
[0022] As shown in Figure 5 A cam assembly, comprising: a first cam set 3-1, a second cam set 3-2, and a third cam set 3-3, the first cam set 3-1 being used to drive the first valve piece 5 to move, the second cam set 3-2 being used to drive the extrusion piece 6 to move, and the third cam set 3-3 being used to drive the second valve piece 7 to move, the first cam set 3-1 being provided with cam structure according to a first far rest angle, a first return angle, and a first push angle, the second cam set being provided with cam structure according to a second far rest angle, a second return angle, a second near rest angle, and a second push angle, and the third cam set being provided with cam structure according to a third far rest angle, a third return angle, and a third push angle; the third far rest angle being greater than the sum of the second return angle and the second near rest angle, and the sum of the second return angle and the second near rest angle being greater than the sum of the first return angle and the first push angle; and the first far rest angle being greater than the sum of the second far rest angle and the second push angle, and the sum of the second far rest angle and the second push angle being greater than the sum of the third return angle and the third push angle, so that the cam assembly designed in the motion process enters the working area later than the second far rest angle.
[0023] A transmission device, comprising: an electric motor 1, a through coupling 2, a first cam set 3-1, a second cam set 3-2, a third cam set 3-3, a counting sensor 4, and a pressure sensor 8, the electric motor 1 driving the first cam set 3-1, the second cam set 3-2, and the third cam set 3-3 to rotate through the through coupling 2. The counting sensor 4 is arranged above the cam assembly 3 to collect the number of rotations of the cam assembly. The pressure sensor 8 is arranged outside the infusion pipeline 9 to collect the pressure of the infusion pipeline 9, and an alarm is given when the pressure threshold is exceeded.
[0024] An electronic infusion pump adopts the transmission device. The liquid in the infusion pipeline flows by rotating the cam assembly in the transmission device according to the working timing.
[0025] The specific working process of the electronic infusion pump is as follows, refer to Figure 3 : Liquid aspiration stage (V aspiration): Figure 3 It can be seen that the graph of the second valve member 7 is a straight line with the highest point, indicating that the second valve member 7 is in the highest position. At this time, the second valve member 7 squeezes the infusion line 9, closing the corresponding infusion line 9 and maintaining it for a period of time. At this stage, the third cam group 3-3 corresponding to the second valve member 7 is in the third far repose angle stage, and the cam structure is a circular arc segment with equal radius, specifically: Figure 6 The oblique line area at the 3-3 position of the third cam group.
[0026] At this time, the first valve member 5 and the extrusion member 6 are Figure 3 The middle part is a gradually downward curve, that is, the first valve 5 and the extrusion member 6 are moving away from the infusion line 9, opening the corresponding infusion line 9. Figure 3 It can be seen that the extrusion member 6 reaches the lowest point before the first valve 5, which can ensure that the corresponding infusion pipeline gradually increases in volume, forms a vacuum, and sucks enough liquid from the liquid storage bag 10. The first cam group 3-1 corresponding to the first valve 5 and the second cam group 3-2 corresponding to the extrusion member 6 are specifically shown in FIG. Figure 6 The oblique line area of the first cam group 3-1 and the second cam group 3-2; it can be seen that the second cam group 3-2 reaches the lowest point area earlier than the first cam group 3-1.
[0027] Close the inner valve stage (close the inner valve): the first valve member 5 corresponding to the first cam group 3-1 is the inner valve. Figure 3 It can be seen that the second valve 7 is still at the highest point and is in the state of closing the infusion pipeline 9; the straight line of the extrusion member 6 at the lowest point of the stroke indicates that the extrusion member 6 stays for a period of time after reaching the lowest point, and the corresponding second cam group 3-2 is in the second near-rest angle stage, and the cam structure is a circular arc segment with a constant radius, that is, Figure 7 At this stage, the first valve member 5 is an ascending curve, and the first valve member gradually approaches the infusion line 9. After reaching the highest point, the infusion line 9 is closed. Figure 7 It can be seen that the radius of the arc surface of the first cam group 3-1 of the first valve member 5 gradually increases, and gradually moves to the first distal repose angle stage of the first cam group 3-1. The time when the first cam group 3-1 moves to the first distal repose angle stage is earlier than the time when the second cam group 3-2 starts to move to the next stage. In other words, the first valve member 5 closes first, and then the extrusion member 6 and the second valve member 7 move.
[0028] Drainage phase (V drainage): from Figure 3It can be seen that after the first valve component 5 rises to the highest point, it maintains this position for a period of time. The extrusion component 6 is an upward curve, indicating that the extrusion component 6 begins to approach the infusion line 9 and begins to squeeze the infusion line 9. The second valve component 7 is a downward curve, indicating that the second valve component 7 begins to move away from the infusion line 9. The second valve component 7 opens the infusion line 9, and at the same time, under the squeezing action of the extrusion component 6, the liquid medicine in the infusion line 9 begins to be discharged outward. The key point is that the speed at which the extrusion component 6 rises is slightly faster than the speed at which the second valve component 7 falls, so that positive pressure is always maintained in the infusion line and sufficient liquid can be discharged. Figure 8 In the oblique line area, the first cam group 3-1 is an arc segment with a constant radius, that is, the first cam group 3-1 is in the first far repose angle stage; the second cam group 3-2 is an arc segment with a gradually increasing radius, and the third cam group 3-3 is an arc segment with a gradually decreasing radius.
[0029] Close external valve stage (close external valve): the second valve member 7 corresponding to the third cam group 3-3 is the external valve. Figure 3 It can be seen that the first valve member 5 and the extrusion member 6 are both at their maximum stroke and remain there for a period of time. Figure 9 In the shaded area, the first cam assembly 3-1 and the second cam assembly 3-2 are at the first and second distal repose angles, respectively. At this point, the motion curve of the second valve member 7 is an ascending curve, indicating that the third cam assembly 3-3 of the second valve member 7 begins to push the second valve member 7 toward the infusion line 9. After closing the second valve member 7, the first valve member 5 and the extruding member 6 immediately begin to move away from the infusion line 9, beginning the next round of aspiration.
[0030] This solution specifically optimizes the detailed movements during aspiration and discharge. During aspiration, the extruder 6 moves away from the infusion line faster than the first valve 5. This ensures that the corresponding infusion line gradually increases in volume, creating a vacuum and drawing in sufficient liquid. During discharge, the extruder 6 rises slightly faster than the second valve 7 descends, ensuring a constant positive pressure within the infusion line and sufficient liquid can be discharged. This ensures both accuracy and efficiency.
[0031] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.
Claims
1. A structural design method for a cam assembly, characterized in that: The following steps are involved: S1: According to the standard working process requirements of the cam assembly, determine the setting timing relationship of the first distal repose angle, the first return angle, and the first push angle in the first cam group, the second distal repose angle, the second return angle, the second proximal repose angle, and the second push angle in the second cam group, and the third distal repose angle, the third return angle, and the third push angle in the third cam group, wherein the third distal repose angle is greater than the sum of the second return angle and the second proximal repose angle, and the sum of the second return angle and the second proximal repose angle is greater than the sum of the first return angle and the first push angle; the first distal repose angle is greater than the sum of the second distal repose angle and the second push angle, and the sum of the second distal repose angle and the second push angle is greater than the sum of the third return angle and the third push angle, so that during the movement of the designed cam assembly, the second distal repose angle enters the working area later than the first distal repose angle; S2: Calculate the base circles corresponding to the first cam group, the second cam group, and the third cam group according to the first return angle, the first push angle, the second near-rest angle, the third return angle, and the third push angle; S3: determining initial cam structures of the first cam group, the second cam group, and the third cam group according to the set timing relationship and the base circles corresponding to the first cam group, the second cam group, and the third cam group; S4: Using simulation software, simulate the initial cam structures of the first cam group, the second cam group, and the third cam group to obtain the motion timing relationship of the cam components, and determine whether the motion timing relationship is consistent with the set timing relationship in step S1. If so, output the cam structures of the first cam group, the second cam group, and the third cam group; if not, execute step S5; S5: Adjust the cam structures of the first cam group, the second cam group, and the third cam group, and use the adjusted cam structures as the initial cam structures of the first cam group, the second cam group, and the third cam group, and execute step S4.
2. The structural design method of the cam assembly according to claim 1, characterized in that: The specific steps of step S2 are: using the transition arc radius between the first return angle and the first push angle as the base circle radius of the first cam group; using the radius of the second near-rest angle as the base circle radius of the second cam group; using the transition arc radius between the third return angle and the third push angle as the base circle radius of the third cam group; and obtaining the base circles corresponding to the first cam group, the second cam group, and the third cam group.
3. The structural design method of the cam assembly according to claim 1, characterized in that: The step S5 specifically includes: adjusting the cam structures of the first cam group, the second cam group, and the third cam group according to the standard working process requirements of the cam assembly, so that the cam structures of the first cam group, the second cam group, and the third cam group correspond to the set timing relationship, and using the adjusted cam structures as the initial cam structures of the first cam group, the second cam group, and the third cam group, and executing step S4.
4. A cam assembly comprising: The first cam group, the second cam group, and the third cam group, the first cam group is used to drive the first valve member to move, the second cam group is used to drive the extrusion member to move, and the third cam group is used to drive the second valve member to move, characterized in that: the first cam group sets a cam structure according to the first distal repose angle, the first return angle, and the first push angle, the second cam group sets a cam structure according to the second distal repose angle, the second return angle, the second proximal repose angle, and the second push angle, and the third cam group sets a cam structure according to the third distal repose angle, the third return angle, and the third push angle; the third distal repose angle is greater than the sum of the second return angle and the second proximal repose angle, and the sum of the second return angle and the second proximal repose angle is greater than the sum of the first return angle and the first push angle; the first distal repose angle is greater than the sum of the second distal repose angle and the second push angle, and the sum of the second distal repose angle and the second push angle is greater than the sum of the third return angle and the third push angle, so that during the movement of the designed cam assembly, the second distal repose angle enters the working area later than the first distal repose angle.
5. A transmission device, characterized in that: include: An electric motor, a coupling, and a cam assembly according to claim 4, wherein the electric motor drives the first cam group, the second cam group, and the third cam group to rotate through the coupling.
6. The transmission device according to claim 5, characterized in that Also includes: A counting sensor is provided above the cam assembly to collect the number of rotations of the cam assembly.
7. The transmission device according to claim 5, characterized in that Also includes: A pressure sensor is provided outside the infusion pipeline to collect the pressure of the infusion pipeline.
8. An electronic infusion pump, characterized in that: A transmission device according to any one of claims 5 to 7 is used.