Intravenous drip flow control device

Abstract

To provide a drip infusion flow rate control device that is easy to achieve size reduction and easiness of fine adjustment of a flow rate.SOLUTION: A drip infusion flow rate control device includes a cam surface, and a drive unit that rotates the cam surface. The drip infusion flow rate control device presses a drip tube by the rotation of the cam surface. The cam surface includes a first portion and a second portion in this order toward one side of a circumferential direction. The first portion has a radius increasing toward the one side of the circumferential direction. The second portion has a radius increasing more gradually than the first portion toward the one side of the circumferential direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an infusion rate control device.

Background Art

[0002] An infusion rate control device that presses an infusion tube is known (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is desirable that the infusion rate control device as described above is small and that fine adjustment of the flow rate is easy.

[0005] Therefore, an object of the present disclosure is to provide an infusion rate control device that can easily achieve miniaturization and easy fine adjustment of the flow rate.

Means for Solving the Problems

[0006] One aspect of the present disclosure is as follows.

[0007] [1] An infusion rate control device having a cam surface and a drive unit that rotates the cam surface, wherein the infusion tube is pressed by the rotation of the cam surface, the cam surface has a first portion and a second portion in this order facing one side in the circumferential direction, the first portion has a radius that increases toward the one side in the circumferential direction, and the second portion has a radius that increases more gently than the first portion toward the one side in the circumferential direction.

[0008] [2] The drip flow rate control device according to [1], having a slip prevention structure that prevents slippage of the cam surface by frictional force when the drive unit is not in operation.

[0009] [3] The drip flow rate control device according to [2], wherein the second portion has the anti-slip structure.

[0010] [4] The drip flow rate control device according to [3], wherein the first portion does not have the anti-slip structure.

[0011] [5] The drip flow rate control device according to any one of [1] to [4], wherein the cam surface has a third portion with a constant radius located on one side in the circumferential direction relative to the second portion.

[0012] [6] A transition portion connecting the circumferential end of the second portion and the circumferential end of the first portion, A drip flow rate control device according to any one of [1] to [5], comprising: a reference adjustment unit that adjusts the rotational position of the cam surface in cooperation with the transition unit.

[0013] [7] The drip flow control device according to any one of [1] to [6], wherein the second portion is provided over an angular range larger than the angular range in which the first portion is provided.

[0014] [8] The drip flow control device according to any one of [1] to [7], wherein the second portion is provided over an angular range of 180 to 270°.

[0015] [9] The drip flow control device according to any one of [1] to [8], wherein the first portion is provided over an angular range of 30 to 60°.

[0016]

[10] The drip flow rate control device according to any one of [1] to [9], wherein the amount of change in radius between both circumferential ends of the second part is 0.6 to 1.0 mm.

[0017]

[11] The drip flow rate control device according to any one of [1] to

[10] , wherein the amount of change in radius between both circumferential ends of the first part is 1.33 to 1.73 mm.

[0018]

[12] The drip flow rate control device according to any one of [1] to

[11] , comprising a pressing member that presses the drip tube by being pressed by the cam surface.

[0019]

[13] Comprising a detection part for detecting the flow rate in the drip chamber, The drip flow rate control device according to any one of [1] to

[12] , wherein the driving part rotates the cam surface according to the detection result of the detection part.

[0020]

[14] The drip flow rate control device according to

[13] , comprising the drip chamber and the drip tube.

Advantages of the Invention

[0021] According to the present disclosure, it is possible to provide a drip flow rate control device that can easily achieve miniaturization and easy fine adjustment of the flow rate.

Brief Description of the Drawings

[0022] <​​​​​​​​​​​​​​ [Figure 3D] This is a top view showing the state after the cam has rotated further from the state shown in Figure 3C. [Figure 4] Figure 1 is an explanatory diagram showing the force acting between the cam and the pressing member. [Modes for carrying out the invention]

[0023] The embodiments of this disclosure will be described in detail below with reference to the drawings.

[0024] As shown in Figure 1, an intravenous drip flow control device 1 according to one embodiment of the present disclosure includes an infusion controller 2, a drip chamber 3, and an intravenous tube 4. In this embodiment, the intravenous drip flow control device 1 injects a liquid such as physiological saline or a nutrient solution into a living body such as a human body via the drip chamber 3 and the intravenous tube 4. The infusion controller 2 includes a cam 5, a pressing member 6, a drive unit 7, and a detection unit 8. The infusion controller 2 may have a housing 9 that at least partially houses and holds the cam 5, the pressing member 6, the drive unit 7, and the detection unit 8, as shown in the figure. The infusion controller 2 may also have a battery (not shown) in the housing 9 as a power source for the drive unit 7 and the detection unit 8. The housing 9 includes a drip chamber housing 10 that houses the drip chamber 3 and a tube housing 11 that houses the upper end portion of the intravenous tube 4. The infusion controller 2 functions as an electric clamp that automatically adjusts the pressing force to narrow the intravenous tube 4 in order to limit the flow rate due to gravity.

[0025] With an electric clamp, even when the flow rate becomes unstable due to factors such as the height difference between the IV bag and the human body, the thickness of the needle in the IV set, the viscosity of the liquid, or changes in the liquid level in the IV bag over time, the flow rate can be automatically stabilized.

[0026] The drip chamber 3 has an inlet 3a, a dripping section 3b, and an outlet 3c. The inlet 3a, dripping section 3b, and outlet 3c are arranged in this order facing downwards in the vertical direction. The outlet 3c is connected to one end (upper end) of the drip tube 4. Liquid that flows into the drip chamber 3 from a liquid container such as an infusion bag through the inlet 3a drips down in the dripping section 3b, flows out of the drip chamber 3 through the outlet 3c, and is injected into the body through the drip tube 4. The amount of liquid dripped in the dripping section 3b corresponds to the flow rate of liquid injected into the body, i.e., the flow rate of the infusion.

[0027] The detection unit 8 detects the flow rate in the drip chamber 3. The detection unit 8 can be configured, for example, by a drip sensor that detects the liquid dripping in the dripping section 3b. As the drip sensor, for example, an optical sensor such as an infrared sensor or an ultrasonic sensor can be used.

[0028] The drive unit 7 rotates the cam 5 around the rotation axis O. The drive unit 7 may have an electric motor 7a and a reduction gear 7b, as shown in the figure. The reduction gear 7b transmits the rotation of the output shaft of the electric motor 7a to the cam 5 at a reduced rotational speed. The reduction gear 7b may be configured, for example, by a gear mechanism as shown in the figure. As the electric motor, for example, a DC motor, AC motor, stepping motor, or servo motor can be used. With an electric motor, the cam 5 can be easily used in a wide angular range, for example, 360°, and the angle can be easily controlled. A computer (processor), not shown, capable of communicating with the detection unit 8, is located inside the housing 9. The computer controls the rotation of the output shaft of the electric motor 7a (rotation direction, rotation position, rotational speed, etc.) according to the detection result (detected flow rate) of the detection unit 8, and as a result controls the rotation of the cam 5. In this way, the drive unit 7 selectively rotates the cam 5 in one circumferential direction and the other circumferential direction according to the detection result of the detection unit 8.

[0029] The cam 5 has a cam surface 12 formed by the outer circumferential surface of the cam 5. The cam surface 12 rotates around the rotation axis O in conjunction with the rotation of the cam 5 by the drive unit 7. The drip flow rate control device 1 controls the drip flow rate by pressing the drip tube 4 with the rotation of the cam surface 12. By using a configuration in which the drip flow rate is controlled by a rotating cam surface 12, it is possible to achieve miniaturization (and weight reduction) of the drip flow rate control device 1 compared to configurations using linkage mechanisms, rack and pinion, or lead screw mechanisms.

[0030] Miniaturization and weight reduction can achieve the following effects: (i) improved portability, reducing the burden on patients with limited physical strength; (ii) improved equipment management, reducing storage space and lessening the burden on hospitals, etc.; (iii) improved ease of use, making it easy to use in limited spaces such as home healthcare; and (iv) improved medical economics, enabling lower prices.

[0031] As shown in Figure 2, the cam surface 12 has a first portion 12a and a second portion 12b in that order, facing one side in the circumferential direction with respect to the axis of rotation O. The first portion 12a has a radius that increases toward one side in the circumferential direction (counterclockwise direction in Figure 2), and the second portion 12b has a radius that increases more gradually toward one side in the circumferential direction than the first portion 12a. The cam surface 12 also has a third portion 12c with a constant radius located toward one side in the circumferential direction from the second portion 12b, and a fourth portion 12d with a constant radius located toward the other side in the circumferential direction from the first portion 12a (clockwise direction in Figure 2).

[0032] The fourth part 12d, the first part 12a, the second part 12b, and the third part 12c can be configured, for example, to be continuously connected in this order on one side in the circumferential direction, as shown in the figure. The radius of the first part 12a can be configured to gradually and smoothly increase toward one side in the circumferential direction, as shown in the figure. The radius of the first part 12a can be configured to increase at a constant gradient toward one side in the circumferential direction, as shown in the figure. The radius of the second part 12b can be configured to gradually and smoothly increase toward one side in the circumferential direction, as shown in the figure. The radius of the second part 12b can be configured to increase at a constant gradient smaller than that of the first part 12a toward one side in the circumferential direction, as shown in the figure.

[0033] As shown in the figure, it is preferable that the second portion 12b is provided over an angular range (also called the second angular range θ2) that is larger than the angular range (also called the first angular range θ1) over which the first portion 12a is provided.

[0034] The larger the second angular range θ2, the larger the range of drip flow rate settings that can be finely adjusted by the second part 12b, which is preferable. The second angular range θ2 is preferably 180° or more, more preferably 200° or more, and more preferably 220° or more. Furthermore, the second angular range θ2 is preferably 270° or less, more preferably 250° or less, and more preferably 230° or less. The second angular range θ2 is determined in consideration of the first angular range θ1, the third angular range θ3, and the fourth angular range θ4.

[0035] The smaller the first angular range θ1, the easier it is to set the second angular range θ2 to be larger. However, due to the rapid increase in the radius of the first part 12a, the torque required of the electric motor 7a increases. From the viewpoint of reducing the required torque and miniaturizing the electric motor 7a and, consequently, the drip flow rate control device 1, the first angular range θ1 is preferably 30° or more, more preferably 35° or more, and more preferably 40° or more. Furthermore, from the viewpoint of making it easier to set the second angular range θ2 to be larger, the first angular range θ1 is preferably 60° or less, more preferably 55° or less, and more preferably 50° or less.

[0036] In particular, the sum of the second angular range θ2 and the first angular range θ1 is preferably 250° or more, more preferably 255° or more, and even more preferably 260° or more. Furthermore, the sum of the second angular range θ2 and the first angular range θ1 is preferably 290° or less, more preferably 285° or less, and even more preferably 280° or less.

[0037] The angular range in which the third portion 12c is provided (also called the third angular range θ3) needs to be of a certain size in order to obtain the effect of suppressing excessive crushing of the drip tube 4 by keeping the radius of the third portion 12c constant. From this viewpoint, the third angular range θ3 is preferably 20° or more, and more preferably 25° or more. Furthermore, from the viewpoint of making it easier to set a larger second angular range θ2, the third angular range θ3 is preferably 40° or less, and more preferably 35° or less.

[0038] The angular range in which the fourth portion 12d is provided (also called the fourth angular range θ4) needs to be of a certain size corresponding to the width of the pressing member 6 (i.e., the circumferential width at the rear end 6b) in order to ensure that the drip tube 4 is not substantially narrowed by keeping the radius of the fourth portion 12d constant. From this viewpoint, the fourth angular range θ4 is preferably 50° or more, and more preferably 55° or more. Furthermore, from the viewpoint of making it easier to set the second angular range θ2 to be large, the fourth angular range θ4 is preferably 70° or less, and more preferably 65° or less.

[0039] The change in radius between the circumferential ends of the second part 12b (r3-r2), which is obtained by subtracting the radius at the other circumferential end of the second part 12b (second radius r2) from the radius at one circumferential end of the second part 12b (third radius r3), is preferably 0.6 mm or more, more preferably 0.65 mm or more, and even more preferably 0.7 mm or more. The change in radius between the circumferential ends of the second part 12b is preferably 1.0 mm or less, more preferably 0.95 mm or less, and even more preferably 0.9 mm or less.

[0040] The gradient ((r3-r2) / θ2) of the second part 12b is preferably 0.0022 (≒0.6 / 270) mm / deg or more, more preferably 0.0026 (≒0.65 / 250) mm / deg or more, and more preferably 0.0030 (≒0.70 / 230) mm / deg or more. The gradient of the second part 12b is preferably 0.0056 (≒1.0 / 180) mm / deg or less, more preferably 0.0048 (≒0.95 / 200) mm / deg or less, and more preferably 0.0041 (≒0.9 / 220) mm / deg or less.

[0041] The change in radius between the circumferential ends of the first part 12a (r2-r1), which is obtained by subtracting the radius at the other circumferential end of the first part 12a (first radius r1) from the radius at one circumferential end of the first part 12a (second radius r2), is preferably 1.33 mm or more, more preferably 1.38 mm or more, and more preferably 1.43 mm or more. The change in radius between the circumferential ends of the first part 12a is preferably 1.73 mm or less, more preferably 1.68 mm or less, and more preferably 1.63 mm or less.

[0042] The gradient ((r2-r1) / θ1) of the first part 12a is preferably 0.022 (≒1.33 / 60) mm / deg or more, more preferably 0.025 (≒1.38 / 55) mm / deg or more, and more preferably 0.029 (≒1.43 / 50) mm / deg or more. The gradient of the first part 12a is preferably 0.058 (≒1.73 / 30) mm / deg or less, more preferably 0.048 (≒1.68 / 35) mm / deg or less, and more preferably 0.041 (≒1.63 / 40) mm / deg or less.

[0043] The first radius r1 is preferably 5.07 mm or more, more preferably 5.12 mm or more, and even more preferably 5.17 mm or more. The first radius r1 is preferably 5.47 mm or less, more preferably 5.42 mm or less, and even more preferably 5.37 mm or less.

[0044] The pressing member 6 presses against a predetermined portion 4a of the drip tube 4 by being pressed by the cam surface 12. The predetermined portion 4a of the drip tube 4 is restricted from moving within the tube housing 11 by being pressed from one side by the pressing member 6, thereby narrowing and reducing the flow rate.

[0045] The pressing member 6 can be held in the housing 9 in such a way that it can advance relative to a predetermined portion 4a of the drip tube 4 to narrow the predetermined portion 4a and reduce the flow rate (from the position shown in Figure 3A to the position shown in Figure 3D), and can also retract relative to the predetermined portion 4a of the drip tube 4 to expand due to elastic force (restoring force from the elastic deformation of the drip tube 4) and increase the flow rate (from the position shown in Figure 3D to the position shown in Figure 3A).

[0046] In this case, as the cam 5 rotates to the other side in the circumferential direction, the radius at the point of contact P between the cam surface 12 and the retraction end (also called the rear end 6b) of the pressing member 6 increases. As a result, the rear end 6b of the pressing member 6 is pressed by the cam surface 12 against the reaction force F1 from the drip tube 4 acting on the forward end (also called the front end 6a) of the pressing member 6, causing the pressing member 6 to move forward. Also, as the cam 5 rotates to one side in the circumferential direction, the radius at the point of contact P between the cam surface 12 and the rear end 6b of the pressing member 6 decreases, causing the pressing member 6 to move backward due to the pressing force from the drip tube 4. In addition, a biasing member such as a spring that biases the pressing member 6 in the retraction direction may be provided to assist the retraction movement of the pressing member 6.

[0047] As shown in Figure 3A, a predetermined portion 4a of the drip tube 4 can be positioned within the tube housing 11 such that, for example, when the contact point P between the cam surface 12 and the pressing member 6 is at the fourth portion 12d, it is approximately in contact with the front end portion 6a of the pressing member 6 and is in its natural state before elastic deformation.

[0048] From this state, as shown in Figure 3B, the cam surface 12 is rotated to the other side in the circumferential direction. When the contact point P between the cam surface 12 and the pressing member 6 is at the first portion 12a, the steep slope of the first portion 12a allows the pressing member 6 to be advanced with a small rotation angle. Therefore, the deformation range of the drip tube 4, which is not actually used to adjust the drip flow rate, can be efficiently deformed with a small rotation angle of the cam surface 12. As a result, it becomes possible to set a larger angular range for the second portion 12b, which is actually used to adjust the drip flow rate. Therefore, as shown in Figure 3C, it becomes possible to easily and accurately fine-tune the drip flow rate using the second portion 12b.

[0049] As shown in Figure 4, the reaction force F1 from the pressing member 6 is generated at the contact point P between the cam surface 12 and the rear end 6b of the pressing member 6, in the direction of the backward movement of the pressing member 6. Therefore, if the rear end 6b of the pressing member 6 is a planar shape perpendicular to the backward movement, the reaction force F1 from the pressing member 6 acting on the sloping portion (first portion 12a and second portion 12b) of the cam surface 12, where the radius increases toward one side in the circumferential direction, generates a rotational moment M that rotates the cam 5 (cam surface 12) toward one side in the circumferential direction, because the extension of the vector of the reaction force F1 is offset from the axis of rotation O.

[0050] Therefore, it is preferable that the drip flow rate control device 1 has a slip prevention structure 13 (see Figure 4) that prevents the cam surface 12 from slipping by frictional force F2 when the drive unit 7 is not operating. The slip prevention structure 13 prevents the cam surface 12 from rotating due to the rotational moment M when the drive unit 7 is not operating, which would cause the drip flow rate to become unstable. Therefore, after adjusting the drip flow rate by rotating the cam surface 12, the power to the drive unit 7 can be turned off, making it easier to achieve power saving. In addition, the required power supply (battery) is smaller, making it easier to achieve miniaturization. Furthermore, an AFF (Anti-free flow) function can be realized, which prevents the drip flow rate from increasing due to unintended power interruption.

[0051] The anti-slip structure 13 can be formed by applying means such as molding with a high-friction material, molding to create an uneven surface, post-processing to create an uneven surface (such as blasting), or attaching a high-friction material to at least one of the cam surface 12 and the rear end portion 6b of the pressing member 6.

[0052] From the viewpoint of power saving, it is preferable to provide the anti-slip structure 13 in the second part 12b, which is the part that adjusts the drip flow rate. From the viewpoint of power saving, it is preferable not to provide the anti-slip structure 13 in the first part 12a, which is not the part that adjusts the drip flow rate. From the viewpoint of power saving, it is preferable to provide the anti-slip structure 13 in the second part 12b and not in the first part 12a or the rear end portion 6b of the pressing member 6.

[0053] As shown in Figure 3C, when the cam surface 12 rotates further in the circumferential direction from the state where the contact point P between the cam surface 12 and the pressing member 6 is at the second portion 12b, and as shown in Figure 3D the contact point P between the cam surface 12 and the pressing member 6 is at the third portion 12c, the radius of the third portion 12c remains constant, which prevents the drip tube 4 from being excessively crushed, and as a result, prevents damage from occurring.

[0054] The drip flow rate control device 1 preferably has a reference adjustment section 14 for adjusting the rotational position of the cam surface 12 in order to improve the control accuracy of the drip flow rate. The reference adjustment section 14 can be configured to adjust the rotational position of the cam surface 12 by coordinating with a transition section 15 that connects one circumferential end of the second section 12b and the other circumferential end of the first section 12a. The reference adjustment section 14 preferably performs the reference adjustment in cooperation with a stepped section 15a whose radius changes in a stepped manner. In this embodiment, the transition section 15 has a third section 12c, a fourth section 12d, and a stepped section 15a that connects one circumferential end of the third section 12c and the other circumferential end of the fourth section 12d.

[0055] The reference alignment unit 14 can be configured to detect the rotational position of the cam surface 12 by rotating the cam surface 12 and detecting the rotational position of the stepped portion 15a using a switch (such as a push-down switch, optical sensor, or magnetic sensor). Alternatively, the reference alignment unit 14 may be configured to perform reference alignment of the rotational position of the cam surface 12 by rotating the cam surface 12 and stopping the rotation by bringing the stepped portion 15a against a stopper.

[0056] This disclosure is not limited to the embodiments described above and can be modified in various ways without departing from its essence.

[0057] Therefore, the drip flow rate control device 1 according to the above embodiment is a drip flow rate control device 1 that has a cam surface 12 and a drive unit 7 for rotating the cam surface 12, and presses the drip tube 4 by the rotation of the cam surface 12, and can be modified in various ways as long as the cam surface 12 has a first portion 12a and a second portion 12b facing one side in the circumferential direction in that order, the first portion 12a has a radius that increases toward one side in the circumferential direction, and the second portion 12b has a radius that increases more gently toward one side in the circumferential direction than the first portion 12a.

[0058] For example, the cam surface 12 may be configured to not have one or both of the third portion 12c and the fourth portion 12d. The drip flow control device 1 may be configured to directly press the drip tube 4 without using the pressing member 6. The drip flow control device 1 may be configured not to have the anti-slip structure 13. The drip flow control device 1 may be configured not to have the reference alignment portion 14.

[0059] Furthermore, it is preferable that the drip flow rate control device 1 according to the above embodiment has a slip prevention structure 13 that prevents slippage of the cam surface 12 by frictional force F2 when the drive unit 7 is not in operation.

[0060] The drip flow rate control device 1 according to the above embodiment is preferably a drip flow rate control device 1 in which the second part 12b has a slip prevention structure 13.

[0061] In the aforementioned embodiment, it is preferable that the drip flow rate control device 1 is such that the first portion 12a does not have a slip prevention structure 13.

[0062] In the aforementioned embodiment, it is preferable that the drip flow rate control device 1 has a third portion 12c with a constant radius on one side in the circumferential direction of the cam surface 12 relative to the second portion 12b.

[0063] The drip flow rate control device 1 according to the above-described embodiment preferably has a transition portion 15 that connects one circumferential end of the second portion 12b and the other circumferential end of the first portion 12a, and a reference adjustment portion 14 that adjusts the rotational position of the cam surface 12 in cooperation with the transition portion 15.

[0064] In the aforementioned embodiment, it is preferable that the drip flow rate control device 1 is such that the second portion 12b is provided over an angular range larger than the angular range in which the first portion 12a is provided.

[0065] The drip flow rate control device 1 according to the above-described embodiment is preferably a drip flow rate control device 1 in which the second portion 12b is provided over an angular range of 180 to 270°.

[0066] The drip flow rate control device 1 according to the above embodiment is preferably a drip flow rate control device 1 in which the first portion 12a is provided over an angular range of 30 to 60°.

[0067] The drip flow rate control device 1 according to the above embodiment is preferably a drip flow rate control device 1 in which the change in radius between the circumferential ends of the second portion 12b is 0.6 to 1.0 mm.

[0068] The drip flow rate control device 1 according to the above embodiment is preferably a drip flow rate control device 1 in which the change in radius between the circumferential ends of the first portion 12a is 1.33 to 1.73 mm.

[0069] The drip flow rate control device 1 according to the above embodiment is preferably a drip flow rate control device 1 that has a pressing member 6 that presses the drip tube 4 when pressed by a cam surface 12.

[0070] The drip flow rate control device 1 according to the above embodiment has a detection unit 8 that detects the flow rate in the drip chamber 3, Preferably, the drip flow rate control device 1 is such that the drive unit 7 rotates the cam surface 12 according to the detection result of the detection unit 8.

[0071] The drip flow rate control device 1 according to the above-described embodiment is preferably a drip flow rate control device 1 having a drip chamber 3. [Explanation of symbols]

[0072] 1. Infusion flow control device 2. Injection Controller 3 Drip tube 3a Inlet 3b Dripping part 3c Outlet 4. Intravenous drip tube 4a Predetermined part 5 Cam 6 Pressing member 6a Front end 6b Rear end 7 Drive Unit 7a Electric motor 7b reducer 8 Detection unit 9 cabinets 10. Drip chamber housing 11 Tube housing section 12 Cam surface 12a Part 1 12b Part 2 12c 3rd part 12d 4th part 13. Anti-slip structure 14. Reference Alignment Section 15. Transition section 15a Stepped section F1 reaction force F2 Friction force M rotational moment O Rotation axis P contact r1 First radius r2 2nd radius r3 3rd radius θ1 First angular range θ2 Second angular range θ3 Third Angular Range θ4 4th angular range

Claims

1. An intravenous drip flow control device having a cam surface and a drive unit for rotating the cam surface, wherein the rotation of the cam surface presses against the intravenous drip tube, The cam surface has a first portion and a second portion facing one side in the circumferential direction, The first portion has a radius that increases toward one side in the circumferential direction, The second portion has a radius that increases more gradually than the first portion toward one side in the circumferential direction, A drip flow rate control device having a slip prevention structure that prevents slippage of the cam surface by frictional force when the drive unit is not in operation.

2. The drip flow rate control device according to claim 1, wherein the second portion has the anti-slip structure.

3. The drip flow rate control device according to claim 2, wherein the first portion does not have the anti-slip structure.

4. The drip flow rate control device according to claim 1, wherein the cam surface has a third portion with a constant radius on one side in the circumferential direction relative to the second portion.

5. A transition portion connecting the circumferential end of the second portion and the circumferential end of the first portion, The drip flow rate control device according to claim 1, further comprising a reference adjustment unit that performs reference adjustment of the rotational position of the cam surface in cooperation with the transition unit.

6. The drip flow rate control device according to claim 1, wherein the second portion is provided over an angular range larger than the angular range in which the first portion is provided.

7. The drip flow rate control device according to claim 1, wherein the second portion is provided over an angular range of 180 to 270°.

8. The drip flow rate control device according to claim 1, wherein the first portion is provided over an angular range of 30 to 60°.

9. The drip flow rate control device according to claim 1, wherein the change in radius between the circumferential ends of the second portion is 0.6 to 1.0 mm.

10. The drip flow rate control device according to claim 1, wherein the change in radius between the circumferential ends of the first portion is 1.33 to 1.73 mm.

11. The drip flow rate control device according to claim 1, further comprising a pressing member that presses the drip tube by being pressed by the cam surface.

12. It has a detection unit that detects the flow rate inside the drip chamber, The drip flow rate control device according to claim 1, wherein the drive unit rotates the cam surface according to the detection result of the detection unit.

13. The drip flow rate control device according to claim 12, comprising the drip chamber.

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