JP2020020590A - Positive displacement flow detector and motion conversion mechanism - Google Patents

Abstract

To decrease a size of two directions of three directions orthogonal to each other in a positive displacement flow detector.SOLUTION: A motion conversion mechanism is disposed in a center between four cylinders 11 which are formed in a main block 1 such as to be arranged in a circumferential direction of a circle, with an axial direction being a vertical direction, and is provided with a shaft 72 extending upwardly from the main block 1. Each cylinder 11 has a piston 8 inserted therein, the piston 8 being connected to the motion conversion mechanism by a connecting rod 9 such that each piston 8 differs in phase by π/2 from one to the next in sequence in which to be circumferentially arranged. The motion conversion mechanism converts linear reciprocating motion of the piston 8 connected by the connecting rod 9 to rotational motion of the shaft 72.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a positive displacement type flow detector and a motion conversion mechanism that can be used for the positive displacement type flow detector.

As a positive displacement type flow detector, a piston type positive displacement type flow detector shown in FIG. 9 is known (for example, Patent Document 1).
The positive displacement type flow detector illustrated in FIG. 9 includes four cylinders 11_1-11_4 sequentially oriented in different directions by 90 °, and four pistons 12_1-11_4 reciprocating in the cylinders 11_1-11_4. . These four pistons 12_1-12_4 perform reciprocating motions whose phases are sequentially shifted by π / 2 in each cylinder 11_1-11_4, as shown in FIGS. 9a-d.

  A crankshaft 13 is provided at the center of the four cylinders 11_1-11_4, and each piston 12_1-12_4 is connected to a position eccentric from the rotation axis of the crankshaft 13 by each connecting rod 14_1-14_4. I have. The movement of the pistons 12_1-12_4 is transmitted to the crankshaft 13 via the connecting rods 14_1-14_4, and the crankshaft 13 rotates in the direction of the arrow X due to the movement of the pistons 12_1-12_4.

  The inlet of the positive displacement type flow detector is connected to the space on the crankshaft 13 side of each of the cylinders 11_1-11_4. Ports P1-P4 of the respective flow paths 15_1-15_4 are connected to positions of the respective cylinders 11_1-11_4 on the outer peripheral side of the positive displacement type flow detector. In addition, these flow paths 15_1-15_4 are connected to the inner cylinder side position of the positive displacement type flow detector of the adjacent cylinders 11_1-11_4, and the flow paths 15_1-15_4 of the adjacent cylinders 11_1-11_4 are connected. Ports E1 to E4 are provided at positions adjacent to the outlet, and are connected to the outlet of the positive displacement type flow detector.

  In such a configuration, the fluid flowing from the inflow port into the positive displacement type flow detector is such that the piston 12 has a lower dead center side (inner circumference) than the piston 12 of the first cylinder 11 near the upper dead center on the outer circumference side. Side), and flows through the flow path 15 between the first cylinder 11 and the adjacent second cylinder connected to the inner peripheral side of the first cylinder 11, The fluid flows from the port P of the second cylinder 11 into a space closer to the top dead center than the piston 12 of the second cylinder 11. Then, when the piston 12 of the second cylinder 11 moves toward the top dead center, the fluid flowing into the second cylinder 11 passes through the port P of the second cylinder 11 and the first cylinder 11 And the second cylinder is pushed back to the flow path 15. At this time, the piston 12 of the first cylinder 11 connects the port E of the first cylinder 11 with the opening on the inner peripheral side of the first cylinder 11 of the flow path 15 between the second cylinder 11 and the second cylinder 11. The closed space to be closed is located at a position formed by the constriction provided at the center of the piston and the first cylinder 11, and the fluid pushed back to the flow path 15 by the piston 12 of the second cylinder 11 causes the closed space. Through the space, it is pushed out from the opening on the inner peripheral side of the first cylinder 11 to the port E of the first cylinder 11 and flows out to the outlet.

  As a result, with the movement of each piston 12_1-12_4, it flows in the direction of each arrow (except arrow X) shown in FIGS. 9A-D, and a certain amount of fluid flows out to the outlet side per one rotation of the crankshaft 13.

  Therefore, the flow rate that has passed through the positive displacement flow rate detector can be measured from the rotation amount of the crankshaft 13.

JP 2012-181083 A

  When inserting a positive displacement flow detector into a pipe or placing a positive displacement flow sensor near the pipe to detect the flow rate into the pipe through which the fluid of existing equipment or machinery flows, the direction in which the pipe extends Can provide a relatively large space for disposing the positive displacement flow detector, while the direction perpendicular to the pipe extension direction is In many cases, a large space for arranging the flow rate detector cannot be secured.

  When such a flow rate is detected, the size in one direction parallel to the extending direction of the pipe among the sizes in the three orthogonal directions of the positive displacement type flow detector is allowed, but the remaining two directions are allowed. Needs to be small.

  However, in the positive displacement type flow detector shown in FIG. 9, the axial direction of the cylinders is perpendicular to each other for each pair of two cylinders opposed to each other with the crankshaft interposed therebetween. In two directions, it is inevitable that the size of the positive displacement type flow detector becomes larger than twice the cylinder length.

  The motion conversion mechanism provided in the positive displacement type flow detector shown in FIG. 9 for converting a linear reciprocating motion of the piston into a rotary motion by the crankshaft and the connecting rod comprises a piston and the crankshaft while the connecting rod largely swings. In order to transmit the force between the piston and the connecting rod, the side pressure that the piston presses against the inner wall of the cylinder is relatively large due to the difference between the axial direction of the piston and the axial direction of the connecting rod. The pressure loss, which is the difference between the pressure of the fluid flowing from the outlet and the pressure of the fluid flowing out of the outlet, increases.

Therefore, an object of the present invention is to provide a positive displacement type flow detector having a small size in two of three orthogonal directions.
Another object of the present invention is to provide a motion conversion mechanism between a linear reciprocating motion and a rotary motion, which can reduce a side pressure against which the piston is pressed against the inner wall of the cylinder.

  In order to solve the problem, the present invention includes an inlet and an outlet, and a positive displacement type flow detector that detects a flow rate of a fluid flowing from the inlet to the outlet is arranged in the same axial direction. A plurality of cylinders, a plurality of pistons that linearly reciprocate in each cylinder, and transfer a fluid flowing in from the inflow port to the outflow port with the linear reciprocation, and an axial direction that is the same as the axial direction of the cylinder. And a motion conversion mechanism for converting the linear motion of the piston into a rotational motion of the shaft.

  Such a positive displacement type flow sensor, the first direction from the bottom dead center of the piston toward the top dead center side, the second direction is the direction opposite to the first direction, the plurality of cylinders and pistons, The cylinder is arranged along the circumference of a circle having the axis of the shaft as a central axis, the shaft is arranged on the second direction side of the cylinder, and the end of the cylinder in the second direction is an opening, The flow rate detector is provided with a plurality of connecting rods that connect each piston and the motion conversion mechanism through the opening, and the motion conversion mechanism is configured to convert the motion of the connecting rod into a rotational motion of the shaft. May be.

  In this case, each of the connecting rods is moved by the motion conversion mechanism by setting one of the directions along the circumference of a circle around the axis of the shaft as the third direction. And restricts the phase of each piston so that the phase of each piston is delayed by π / 2 with respect to the piston adjacent to the piston in the third direction. The opening of the section is connected to the outflow port, the piston is provided with a constriction at the center in the axial direction, and the positive displacement type flow detector is provided with the inflow opening communicating with the internal space of each cylinder and the flow port. An inflow passage communicating with the inlet, a first opening communicating with the internal space of each cylinder, and a communication passage communicating with the second opening communicating with the internal space of the cylinder adjacent to the cylinder in the third direction. To provide It may be. However, the first opening is provided at least when the piston corresponding to the cylinder adjacent to the cylinder provided with the first opening in the third direction is near bottom dead center. The second opening is provided at a position closer to the top dead center than the piston corresponding to the cylinder, and the piston corresponding to the cylinder provided with the second opening is near the top dead center in the axial direction of the cylinder. When the piston is located at a position closer to the bottom dead center than the piston, and when the piston is near the bottom dead center, the piston is provided at a position within a constricted range of the piston, and the inflow opening is provided in the axial direction of the cylinder. The position is always within the range of the piston corresponding to the cylinder provided with the inflow opening, and when the piston is near the bottom dead center, within the range of the constriction of the piston That it provided in the position.

  According to such a positive displacement type flow detector, since the axes of the cylinder, piston and shaft can all be in the same direction, a positive displacement type flow detector having a small size in two directions orthogonal to the directions of these axes can be realized. . In addition, by increasing the axial size of the cylinder and the stroke amount of the piston, the size of the positive displacement type flow detector per rotation of the shaft can be increased without increasing the size in two directions orthogonal to the directions of these axes. The volume can be expanded.

  Further, in order to solve the problem, the present invention provides, as a motion conversion mechanism for converting between a linear reciprocating motion and a rotary motion, a rotatably supported shaft, and an axis inclined from the rotation axis of the shaft. A motion conversion mechanism including a swash plate supported by the shaft so as to be rotatable relative to the shaft as a rotation axis. The swash plate is constrained not to rotate, and a force having a component in the direction of the rotation axis of the shaft is applied to a position away from the rotation axis of the swash plate in conjunction with the linear reciprocation. .

  The motion conversion mechanism is further supported by the swash plate at a position distant from the rotation axis of the swash plate so as to be rotatable about an axis having a direction from the position toward the rotation axis of the swash plate. The connecting member supporting portion and the object performing a linear reciprocating motion in the rotation axis direction of the shaft are swingably connected along a plane including the rotating shaft of the connecting member supporting portion and the rotating shaft of the shaft. A connection member may be provided. The connecting member supporting portion is connected to the connecting member so that the connecting member can swing about an axis perpendicular to a rotation axis of the connecting member supporting portion as a swing axis. The force is applied to the swash plate from the object via the connecting member support portion and the connecting member.

In this case, the swash plate may be restrained from rotating by the object via the connecting member support and the connecting member.
The motion conversion mechanism provided with these connecting members can be applied as a motion conversion mechanism of the positive displacement type flow detector provided with the connecting rod described above.
In this case, the motion conversion mechanism is provided along the circumference of a circle having the rotation axis of the swash plate as a center axis, and a plurality of the connection member support portions corresponding to each of the plurality of cylinders are provided. The connecting rod connected to the piston of the corresponding cylinder is connected to each connecting member support portion as the connecting member, and in the motion conversion mechanism, each piston is used as the object, from linear reciprocating motion to rotating motion of the shaft. Perform the conversion.

In this case, each of the plurality of pistons may sequentially apply the force to the swash plate via the connecting member connected to the piston and the connecting member support.
Further, the motion conversion mechanism provided with the above-mentioned connecting member is provided with a volume in which the phase of each of the above-mentioned pistons is regulated so as to be delayed by π / 2 from the piston adjacent to the piston in the third direction. When applied as a motion conversion mechanism of a flow rate detector, the plurality of cylinders are arranged at equal angular intervals along a circumference of a circle having the axis of the shaft as a central axis. Providing four connecting member support portions corresponding to each of the four cylinders, the four connecting member support portions being arranged at equal angular intervals along the circumference of a circle having the rotation axis of the swash plate as the center axis, The connecting rod connected to the piston of the corresponding cylinder is connected as the connecting member, and each piston is connected to the piston through the connecting rod and the connecting member support so that the phase of each piston is Is connected to the swash plate so as to have a phase delayed by π / 2 from the piston adjacent in the third direction. In the motion conversion mechanism, the rotation of the shaft is performed from the linear reciprocating motion using each piston as the object. Conversion to exercise may be performed.

  Thus, the linear reciprocating motion of the piston can be converted into the rotational motion of the shaft without substantially swinging the connecting rod, and the side pressure against which the piston is pressed against the inner wall of the cylinder can be reduced.

According to the present invention, it is possible to provide a positive displacement type flow detector having a small size in two of three orthogonal directions.
Further, it is possible to provide a motion conversion mechanism between a linear reciprocating motion and a rotary motion capable of reducing a side pressure against which the piston is pressed against the inner wall of the cylinder.

It is a figure showing appearance of a positive displacement type flow detector concerning an embodiment of the present invention. It is a figure showing the internal composition of the positive displacement type flow detector concerning the embodiment of the present invention. It is a figure showing the shape of the piston concerning the embodiment of the present invention. It is a figure showing a cylinder and a channel of a main block of a positive displacement type flow detector concerning an embodiment of the present invention. FIG. 4 is a diagram illustrating a state of fluid transfer of the positive displacement type flow detector according to the embodiment of the present invention. It is a figure showing composition of a motion conversion mechanism concerning an embodiment of the present invention. It is a figure showing operation of a motion conversion mechanism concerning an embodiment of the present invention. It is a figure showing operation of a motion conversion mechanism concerning an embodiment of the present invention. It is a figure showing composition of a publicly known positive displacement type flow detector.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows the appearance of a positive displacement type flow detector according to the present embodiment.
For convenience, the upper, lower, front, rear, right and left sides of the positive displacement flow detector are determined as shown in the figure. FIG. 1A shows the upper surface of the positive displacement flow sensor, FIG. 1B shows the front surface of the positive displacement flow sensor, and FIG. 1 shows a lower surface of a flow rate detector.

  As shown in the drawing, the positive displacement type flow detector is connected to a main block 1, an inflow side flange 2 connected to a lower part of the main block 1, a cover 3 connected to an upper part of the main block 1, and an upper part of the cover 3. It has an outflow side flange 4, an outflow block 5 connected to an upper part of the outflow side flange 4, and a circuit cover 6 connected to an upper part of the outflow side flange 4.

The inflow-side flange 2 forms an inflow port 21 of a positive displacement type flow detector at the center in the front-rear, left-right direction, and the outflow block 5 forms an outflow port 51 of the positive displacement type flow detector.
Next, FIG. 2a shows a cross section of the positive displacement flow sensor taken along the line AA in FIG. 1a, FIG. 2b shows a cross section taken along the line BB in FIG. 1a, and FIG. 2c shows a cross section of the positive displacement flow sensor taken along the CC line in FIG. , FIG. 2d shows a section taken along line DD in FIG. 1a.

  As shown in the drawing, the positive displacement type flow detector has a space surrounded by an upper surface of the main block 1, an inner peripheral surface of the cover 3, and a lower surface of the outflow side flange 4. Hereinafter, for convenience, this space will be described as “internal space”.

The internal space of the positive displacement type flow detector is connected to the outlet 51 by holes provided in the outlet flange 4 and the outlet block 5.
The main block 1 has four cylinders 11 arranged in a circumferential direction of a circle centered on a vertical axis passing through the center of the main block 1 in the front-rear and left-right directions and having a vertical direction as an axial direction. Are formed. The upper end of each cylinder 11 is open, and the inside of the cylinder 11 is connected to the upper internal space. The lower end of each cylinder 11 is sealed by the inflow side flange 2.

  A motion conversion mechanism is arranged in the center of the upper part of the main block 1 in the front-rear, left-right direction, and housed in the internal space. The motion conversion mechanism includes a shaft bearing 71 fixed to an upper portion of the main block 1, and a shaft 72 extending in the up-down direction, rotatably supported by the shaft bearing 71 about a vertical axis as a rotation axis, and a shaft of the shaft 72. A swash plate 73 and the like are provided so as to be rotatable relative to the shaft 72 with the axis inclined with respect to the axis as the rotation axis.

  Further, a piston 8 is inserted into each cylinder 11, and the phase of each piston 8 is sequentially shifted by a connecting rod 9 on the side of the swash plate 73 of the motion conversion mechanism in the order of arrangement in the circumferential direction. / 2.

Then, the motion converting mechanism converts the linear reciprocating motion of the piston 8 connected by the connecting rod 9 into a rotational motion of the shaft 72 of the motion converting mechanism.
Details of the motion conversion mechanism will be described later.
At the upper end of the shaft 72 of the motion conversion mechanism, a rotation detecting magnet 10 is fixed so as to rotate together with the shaft 72, and a recess provided at a position facing the magnet 10 on the upper surface of the outflow side flange 4 includes: An electronic circuit 402 on which a magnetic field detecting element 401 such as an MR element or a Hall element is mounted is accommodated. Calculate the rotation speed and so on.

The upper part of the electronic circuit 402 is sealed by the circuit cover 6.
Next, FIG. 3A is a perspective view of the piston 8 as viewed obliquely from above, and FIG. 3B is a perspective view of the piston 8 as viewed obliquely from below. The piston 8 has a shape provided with a constriction formed by reducing the diameter at a central portion in the axial direction (vertical direction).

  Now, as shown in FIGS. 2a, 2b, 2c, and 2d, the main block 1 is provided with a common inflow channel 121 and an individual inflow channel 122, and an inflow port connecting the inflow port 21 of the inflow side flange 2 to each cylinder 11. Roads are provided. In addition, the main block 1 is provided with a communication path 123 that connects between the cylinders 11 that are adjacent in the circumferential direction.

Here, FIG. 4A shows an arrangement relationship of the cylinder 11, the common inflow channel 121, the individual inflow channel 122, and the communication channel 123 as viewed from below.
As shown, the common inflow channel 121 is provided at the center of the main block 1, the individual inflow channel 122 extends from the common inflow channel 121 to each cylinder 11, and the communication channel 123 is provided between the adjacent cylinders 11. , Two in parallel with each other in the radial direction of the main block 1.

  In FIG. 4, # 1 to # 4 are identification numbers of the cylinder 11 attached for convenience, and the identification numbers correspond to the left cylinder 11, the front cylinder 11, the right cylinder 11 in the clockwise direction in FIG. 11 and the rear cylinder 11 in this order.

  Next, FIG. 4c1 shows a cross section taken along the line AA in the bottom view of the positive displacement flow detector of FIG. 4b, and FIG. 4c2 shows a cross section taken along the line BB in the bottom view of FIG. 4b. The common inflow path 121 is a flow path extending in the vertical direction that communicates with a hole connected to the inflow port 21 provided in the inflow side flange 2. The flow path extends in the direction.

Next, FIG. 4D shows a cross-sectional view taken along the line C in the bottom view of FIG.
FIG. 4D shows a cross section viewed from the outer peripheral side toward the center, and point k in FIG. 4B corresponds to the left and right ends in FIG.
As shown in FIG. 4D, the communication path 123 is a flow path connecting a position below each cylinder 11 and a position above the adjacent cylinder 11 in the clockwise direction in the circumferential direction in FIG. 4A. In FIG. 4D, the communication path 123 on the center side of the main block 1 among the two communication paths 123 connecting the adjacent cylinders 11 is shown.

  Here, the opening M connected to the inside of the cylinder 11 of the individual inflow passage 122 is formed only when the piston 8 is located near the bottom dead center (upward end of the moving range). It is provided at a position communicating with a space surrounded by the inner wall of the eleventh wall. Further, the opening M of the individual inflow channel 122 is always arranged at a position where the opening M does not fall outside the range of the piston 8 in the vertical direction.

  In addition, among the openings of the communication path 123, the position of the opening P at the upper position, which is the opening on the cylinder 11 side advanced by one clockwise of the cylinder 11 with which the communication path 123 communicates, also indicates that the piston 8 has the bottom dead center. The opening P is provided at a position that communicates with a space surrounded by the constriction of the piston 8 and the inner wall of the cylinder 11 only when it is located near (upward end of the movement range). The opening P at a position above the communication path 123 is a position slightly above the opening M, and only when the piston 8 is located near the top dead center (the lower end of the moving range). 8 above. The opening P communicates with the internal space of the positive displacement flow rate detector via the space above the piston 8 of the cylinder 11 only when the piston 8 is located near the top dead center (the lower end of the movement range). contact.

  Among the openings of the communication path 123, the opening Q at the lower position, which is the opening on the cylinder 11 side advanced by one in the counterclockwise direction of the cylinder 11 with which the communication path 123 communicates, is always up and down which is below the piston 8. The opening Q is always in communication with a space below the piston 8 of the cylinder.

FIG. 5 shows such a fluid transfer operation by the main block 1 and the cylinder 11.
Now, as shown in FIG. 5A, when the piston 8 of the cylinder 11 of # 2 is near the bottom dead center, the opening M and the opening P of the cylinder 11 of # 2 are connected to the inner wall of the cylinder 11 of # 2 and The fluid flowing from the inflow port 21 to the common inflow path 121 and the individual inflow path 122 of the cylinder 11 of # 2 passes through the opening M of the cylinder 11 of # 2. It flows into the space surrounded by the inner wall of the cylinder 11 and the constriction of the piston 8, passes through the opening P of the cylinder 11 of # 2, the communication path 123, the opening Q of the cylinder 11 of # 1, and the piston of the cylinder 11 of # 1. The piston 8 of # 1 is pushed up by the force of the inflowing fluid and moves upward.

Then, the other piston 8 whose phase difference is defined by the motion conversion mechanism also moves counterclockwise with a phase difference of π / 2 from the adjacent piston 8.
The piston 8 of # 3 having a phase difference of π with the piston 8 of # 1 moves downward, and the fluid flowing into the space below the piston 8 of the cylinder 11 of # 3 is transferred to the top dead center by the piston 8. It is pushed out through the opening Q of the cylinder 11 of # 3, the communication path 123, and the opening P of the cylinder 11 of # 4 into the cylinder 11 of # 4, where the opening P is near the piston 8 and above the piston 8. The fluid pushed out above the piston 8 advances into the internal space of the positive displacement type flow detector and flows out from the outlet 51 of the positive displacement type flow detector.

  In the state shown in FIG. 5A, in the cylinders # 1, # 3, and # 4, the opening M is blocked by the piston 8, and the opening P and the space above the piston 8 of the cylinder 11 are both below and below. The fluid does not flow in from the opening M because it is not communicated with. In the state shown in FIG. 5A, in the cylinders # 1, # 2, and # 3, the space above the piston 8 of the cylinder 11 is blocked by the piston 8, so that neither the opening M nor the opening P is in communication. .

  Next, in the state of FIG. 5B in which the phase of each piston 8 is advanced by π / 2 from the state of FIG. 5A, the piston 8 of the cylinder 11 of # 1 is near the bottom dead center, and the opening M of the cylinder 11 of # 1 The opening P communicates with the space surrounded by the inner wall of the cylinder 11 of # 1 and the constriction of the piston 8, and the fluid flowing from the inflow port 21 into the common inflow path 121 and the individual inflow path 122 of the # 1 cylinder 11 Flows into the space surrounded by the inner wall of the # 1 cylinder 11 and the constriction of the piston 8 through the opening M of the # 1 cylinder 11, and the opening P of the # 1 cylinder 11, the communication paths 123, and # 4 The fluid flows into the space below the piston 8 of the # 4 cylinder 11 through the opening Q of the cylinder 11, and the force of the inflowing fluid pushes up the # 4 piston 8 to move upward.

Then, the other piston 8 whose phase difference is defined by the motion conversion mechanism also moves counterclockwise with a phase difference of π / 2 from the adjacent piston 8.
The piston 8 of # 2 having a phase difference of π with the piston 8 of # 4 moves downward, and the fluid flowing into the space below the piston 8 of the cylinder 11 of # 2 is moved to the top dead center by the piston 8. It is pushed out through the opening Q of the cylinder 11 of # 2, the communication path 123, and the opening P of the cylinder 11 of # 3 into the cylinder 11 of # 3, where the opening P is located above the piston 8 and is near. The fluid pushed out above the piston 8 advances into the internal space of the positive displacement type flow detector and flows out from the outlet 51 of the positive displacement type flow detector.

  In the state shown in FIG. 5B, in the cylinders # 2, # 3, and # 4, the opening M is blocked by the piston 8, and the space below the opening P and the space above the piston 8 of the cylinder 11 is also lower. The fluid does not flow in from the opening M because it is not communicated with. In the state of FIG. 5B, in the cylinders # 1, # 2, and # 4, the space above the piston 8 of the cylinder 11 is blocked by the piston 8, and communicates with both the opening M and the opening P. Absent.

  As shown in FIG. 5c showing a state where the phase of the piston 8 has advanced by π / 2 from the state of FIG. 5b, and FIG. 5d showing a state where the phase of the piston 8 has advanced by π / 2 from the state of FIG. The fluid flowing from the opening M of the individual inflow passage 122 of the cylinder #mod (i + 1) is sent to the space below the piston 8 of the cylinder #mod (i), where mod (x) is the remainder of x of x. The operation of flowing the fluid in the space below the piston 8 of the cylinder #mod (i + 2) to the outlet 51 through the space above the piston 8 of the cylinder 11 of the cylinder #mod (i + 3) is denoted by i. , 3, 2, 1, 4, 3, 2, 1, 4, 3,... Are repeatedly performed, and the fluid flowing from the inlet 21 into the common inflow path 121 is It is transferred to 51.

Here, the linear reciprocating motion of the piston 8 is converted into the rotational motion of the shaft 72 by the motion converting mechanism.
Since the volume of the fluid flowing out to the outlet 51 per one reciprocation of the piston 8 is constant, the fluid flowing from the inlet 21 to the outlet 51 through the positive displacement type flow detector per one rotation of the shaft 72. The volume is constant. Therefore, as described above, the flow rate of the fluid flowing from the inlet 21 to the outlet 51 can be measured by detecting the rotation speed of the shaft 72 by the electronic circuit 402.

Next, details of the motion conversion mechanism will be described.
FIG. 6A shows the configuration of the shaft 72 of the motion conversion mechanism.
FIGS. 6a1, a2, a3, and a4 show the appearance of the shaft 72 viewed from the front to the rear of the positive displacement type flow detector when the rotation angles of the shaft 72 are 0, π / 2, π, and 3π / 2, respectively. 6a5 and a6 show the upper surface and the lower surface of the shaft 72 when the rotation angle of the shaft 72 is zero. 6a7 shows the shaft 72 as viewed from obliquely above. The rotation angle of the shaft 72 is measured clockwise when viewed from above.

  As shown in the figure, the shaft 72 has a central cylinder 721 having a cylindrical shape with a part of the upper part having a small diameter, and an inclined disk 722 provided in a flange shape around the central cylinder 721. The inclined disk 722 has a disk shape having an axis inclined with respect to the central axis of the central cylinder 721 as a central axis, and a point (inclined) at the center of the inclined disk 722 on the central axis of the inclined disk 722 in the height direction. The center of the disk 722) is on the central axis of the central cylinder 721.

Next, the configuration of the swash plate 73 is shown in FIG.
Now, for the sake of convenience, it is assumed that the + x direction, the + y direction, and the + z direction of the swash plate 73 are determined as shown in FIG. 6B1, and FIG. 6B1 shows the swash plate 73 viewed from the −y direction toward the + y direction. 6b2 shows the swash plate 73 viewed from the + z direction in the -z direction, and FIG. 6b3 shows the swash plate 73 viewed from the -z direction in the + z direction.

The swash plate 73 is an annular member having a central hole 731 extending in the z direction at the center in the xy directions.
A rod support portion 732 is connected to the outer peripheral surface on the + x direction side, the outer peripheral surface on the −x direction side, the outer peripheral surface on the + y direction side, and the outer peripheral surface on the −y direction side of the swash plate 73, respectively. . Three of the four rod support portions 732 have an arrangement and configuration in which the remaining one rod support portion 732 is rotated by π / 2, π, 3π / 2 around the central axis of the central hole 731. Have.

  FIG. 6B4 shows a cross section taken along line AA of FIG. 6B2. Each rod support portion 732 is supported by a swash plate 73 via a support portion bearing 733, and as shown in FIG. 6b5, a rod support provided on the outer peripheral surface on the + x direction side and the outer peripheral surface on the -x direction side. The portion 732 can rotate with respect to the swash plate 73 with the x direction as a rotation axis, and the rod support portions 732 provided on the outer peripheral surface on the + y direction side and the outer peripheral surface on the −y direction side rotate the y direction in the rotation axis. And can rotate with respect to the swash plate 73.

  Each rod support portion 732 has a swing shaft 734 that pivotally supports the connecting rod 9. As shown in FIG. 6b6, the pivot axis 734 of the rod support portion 732 provided on the outer peripheral surface on the + x direction side and the outer peripheral surface on the −x direction side is in the y direction, and the connecting rod 9 is moved in the x direction. The rocking shaft 734 of the rod support portion 732 provided on the outer peripheral surface on the y direction side and the outer peripheral surface on the −y direction side has an axial direction of the x direction, and connects the connecting rod 9 to the y direction. It is pivotally supported in the direction.

  Next, the front surface when the rotation angle of the shaft 72 is 0 is shown in FIG. 6c1, and the cross section is shown in FIG. 6c2. The swash plate 73 provided with the rod support portion 732 is formed by using a swash plate bearing 74 disposed between the inner wall of the central hole 731 of the swash plate 73 and the outer peripheral surface of the inclined disk 722 of the shaft 72. The central axis of the central hole 731 in the z direction coincides with the central axis of the inclined disk 722, and the central axis of the inclined disk 722 can be rotated around the inclined disk 722 relative to the inclined disk 722 about the central axis of the inclined disk 722. Is connected to the inclined disk 722. Therefore, since the central axis of the inclined disk 722 is inclined with respect to the central axis of the central cylinder 721 of the shaft 72, the swash plate 73 uses the axis inclined with respect to the central axis of the central cylinder 721 of the shaft 72 as the rotation axis. , Around the shaft 72.

  Then, the shaft 72 on which the swash plate 73 is assembled using the swash plate bearing 74 is rotated about a vertical axis as a rotation axis by a shaft bearing 71 fixed to an upper portion of the main block 1 as shown in FIG. It is supported as much as possible.

  As shown in FIG. 7 a 1, the lower end of the connecting rod 9 is connected to four pistons 8. Further, the upper end of the connecting rod 9 is pivotally supported by a swing shaft 734 of each rod support portion 732.

  Here, the arrangement and size of each cylinder 11, the swash plate 73, and the rod support portion 732 are determined such that the swing shaft 734 of the rod support portion 732 passes almost directly above the center of the cylinder 11, that is, the rod support portion 732 The connecting rod 9 pivotally supported by the swing shaft 734 is set to extend substantially vertically.

  Here, FIGS. 7a1, a2, a3, and a4 show the relationship between the piston 8 when the rotation angle of the shaft 72 is 0, π / 2, π, and 3π / 2, respectively, and the shaft 72 and the swash plate 73 of the motion conversion mechanism. It is shown.

  As shown in the figure, the height of the swing shafts 734 of the four rod support portions 732 of the swash plate 73 gradually changes in the order of arrangement around the central axis of the central cylinder 721 of the shaft 72, and returns to the original height after one revolution. , The phase of each piston 8 is different by π / 2.

  As described above, when one of the pistons 8 is pushed upward by the force of the fluid flowing into the space below the piston 8 of the cylinder 11, the connecting rod 9 is connected to the connecting rod 9 via the connecting rod 9 connected to the piston 8. An upward force is applied to the rod supporting portion 732 supported by the swing shaft 734, and this force is a force that changes the inclination of the swash plate 73 and the inclined disk 722. The force that changes the inclination of the inclined disk 722 is applied to the shaft 72 as a force that rotates the shaft 72 so that the inclination of the inclined disk 722 changes.

  Therefore, when one of the pistons 8 is pushed upward by the force of the fluid, the piston 8 moves upward, and the shaft 72 is moved so that the inclination of the swash plate 73 and the inclined disk 722 changes with the movement. While rotating, the other pistons 8 also move in a different phase by π / 2.

  As a result, as shown in FIGS. 7a1, a2, a3, a4, a1, a2,..., The position of the piston 8 and the inclination of the swash plate 73 change, and FIGS. 7b1, b2, b3, b4, b1, b2 ,..., And the linear reciprocating motion of the piston 8 is converted into a rotational motion of the shaft 72 by the motion converting mechanism.

  As shown in FIGS. 7 a 1, a 2, a 3, and a 4, the rod supporting portion 732 is swung according to a change in the inclination of the swash plate 73 so that the connecting rod 9 maintains a posture extending substantially vertically. The shaft 734 rotates with respect to the swash plate 73, and the connecting rod 9 swings with respect to the swing shaft 734.

  On the other hand, as shown in FIG. 8, since the distance d between the swing shaft 734 and the axis of the central cylinder 721 of the shaft 72 slightly changes by Δd according to the inclination of the swash plate 73, the connecting rod 9 is It is necessary to be able to slightly swing from a posture extending in the vertical direction in accordance with the inclination of 73. Therefore, the lower end of the connecting rod 9 is swingably connected to the piston 8 by a piston shaft 81 provided on the piston 8 so that the connecting rod 9 can swing by an angle enough to absorb Δd. The piston shaft 81 extends in a direction perpendicular to the up-down direction and perpendicular to a straight line connecting a point on the central axis of the piston 8 and a point on the axis of the shaft 72. The lower end of the connecting rod 9 is Is pivotally connected to the piston shaft 81 on a plane including the central axis of the shaft 72 and the axis of the shaft 72.

The embodiment of the invention has been described.
In the above embodiment, the case where the number of the sets of the cylinder 11 and the piston 8 is four has been described, but the number of the sets of the cylinder 11 and the piston 8 may be any number as long as it is a multiple of two.

  The motion conversion mechanism described in the above embodiment is a mechanism that can also perform a conversion from a rotary motion to a linear reciprocating motion, and is not limited to the positive displacement type flow detector, and can be applied to any device, from the linear reciprocating motion to the rotary motion. The mechanism can be applied as a mechanism for converting the rotation motion to a linear motion.

  As described above, according to the present embodiment, the axes of the cylinder 11, the piston 8, and the shaft 72 can all be in the same direction. Therefore, it is possible to realize a positive displacement type flow detector having a small size in two directions orthogonal to the directions of these axes.

  Further, by increasing the axial size of the cylinder 11 and the stroke amount of the piston, one rotation of the shaft 72 of the positive displacement type flow detector can be performed without increasing the size in two directions perpendicular to these axial directions. The volume per unit can be increased.

  Further, according to the motion conversion mechanism of the present embodiment, the linear reciprocating motion of the piston 8 can be converted into the rotary motion of the shaft 72 without substantially swinging the connecting rod 9, and the piston 8 The side pressure pressed against the inner wall can be reduced.

  11_1-11_4 ... Cylinder, 12_1-12_4 ... Piston, 13 ... Crankshaft, 14_1-14_4 ... Connecting rod, 15_1-15_4 ... Flow path, 1 ... Main block, 2 ... Inflow side flange, 3 ... Cover, 4 ... Outflow side Flange, 5 outlet block, 6 circuit cover, 7 shaft bearing, 8 piston, 9 connecting rod, 10 magnet, 11 cylinder, 21 inlet, 51 outlet, 72 shaft, 73 ... swash plate, 74 ... swash plate bearing, 81 ... piston shaft, 121 ... common inflow path, 122 ... individual inflow path, 123 ... communication path, 401 ... magnetic field detecting element, 402 ... electronic circuit, 721 ... central cylinder, 722 ... Inclined disk, 731 central hole, 732 rod support, 733 support bearing, 734 rocking shaft.

Claims (9)

A positive displacement type flow detector comprising an inlet and an outlet, and detecting a flow rate of a fluid flowing from the inlet to the outlet,
A plurality of cylinders whose axial direction is aligned in the same direction,
A plurality of pistons that linearly reciprocate in each cylinder and transfer fluid flowing from the inflow port to the outflow port with the linear reciprocation,
A positive displacement type flow detector, comprising: a shaft having an axial direction that is the same as the axial direction of the cylinder; and a motion converting mechanism that converts a linear motion of the piston into a rotational motion of the shaft.
The positive displacement flow detector according to claim 1,
A direction from the bottom dead center of the piston toward the top dead center is a first direction, and a direction opposite to the first direction is a second direction.
The plurality of cylinders and pistons are arranged along a circumference of a circle having the axis of the shaft as a central axis,
The shaft is disposed on the second direction side of the cylinder,
The end of the cylinder in the second direction is open,
The positive displacement flow detector has a plurality of connecting rods connecting each piston and the motion conversion mechanism through the opening,
The displacement conversion mechanism converts a movement of the connecting rod into a rotational movement of the shaft. It is a positive displacement type flow detector of Claim 2, Comprising:
One of the directions along the circumference of a circle having the axis of the shaft as a central axis is defined as a third direction,
The motion conversion mechanism regulates the phase of each piston via each connecting rod such that the phase of each piston is delayed by π / 2 from the piston adjacent to the piston in the third direction. And
An opening at an end on the second direction side of the cylinder communicates with the outlet,
The piston has a constriction at a central portion in the axial direction,
The positive displacement type flow detector,
An inflow opening that communicates with the inflow opening and the inflow port that communicate with the internal space of each cylinder,
A first opening communicating with the internal space of each cylinder, and a communication path communicating with the second opening communicating with the internal space of the cylinder adjacent to the cylinder in the third direction;
The first opening is provided at least in a cylinder provided with the first opening when a piston corresponding to a cylinder adjacent in the third direction to the cylinder provided with the first opening is near bottom dead center. It is provided at a position closer to the top dead center than the corresponding piston,
The second opening is located at a position closer to the bottom dead center than the piston when the piston corresponding to the cylinder provided with the second opening is near the top dead center in the axial direction of the cylinder. When is near the bottom dead center, it is provided at a position within the constriction range of the piston,
The inflow opening is a position which is always within a range of a piston corresponding to the cylinder provided with the inflow opening in the axial direction of the cylinder, and when the piston is near a bottom dead center, A positive displacement type flow detector, which is provided at a position within a range of constriction of a piston.
A motion conversion mechanism for converting between linear reciprocating motion and rotary motion,
A rotatably supported shaft,
A swash plate supported by the shaft, so as to be rotatable relative to the shaft with an axis inclined from the rotation axis of the shaft as a rotation axis,
The swash plate is restrained from rotating,
A motion conversion mechanism, wherein a force having a component in a rotation axis direction of the shaft is applied to a position apart from a rotation axis of the swash plate in conjunction with the linear reciprocating motion.
The motion conversion mechanism according to claim 4, wherein
At a position distant from the rotation axis of the swash plate, a connection member supporting portion supported by the swash plate, rotatable around an axis having a direction from the position toward the rotation axis of the swash plate,
An object that performs a linear reciprocating motion in the rotation axis direction of the shaft, having a connection member that is swingably connected along a plane including the rotation axis of the connection member support portion and the rotation axis of the shaft,
The connecting member supporting portion is connected to the connecting member supporting portion such that the connecting member is swingable about an axis perpendicular to a rotation axis of the connecting member supporting portion as a swing axis,
A motion conversion mechanism, wherein the force is applied to the swash plate from the object via the connection member and the connection member support portion.
The motion conversion mechanism according to claim 4 or 5,
The motion conversion mechanism, wherein the swash plate is restrained from rotating by the object via the connecting member supporting portion and the connecting member.
It is a positive displacement type flow detector of Claim 2, Comprising: The motion conversion mechanism of Claim 5 or 6 is provided as said motion conversion mechanism,
The motion conversion mechanism is disposed along a circumference of a circle having the rotation axis of the swash plate as a central axis, and has a plurality of the connection member support portions corresponding to each of the plurality of cylinders,
The connecting rod connected to the piston of the corresponding cylinder is connected to each connecting member support portion as the connecting member,
The motion conversion mechanism converts a linear reciprocating motion into a rotary motion of the shaft by using each piston as the object, and outputs the displacement. It is a positive displacement type flow detector of Claim 7, Comprising:
Each of the plurality of pistons sequentially applies the force to the swash plate via the connecting member connected to the piston and the connecting member support portion.
It is a positive displacement type flow detector of Claim 3, Comprising: The motion conversion mechanism of Claim 5 or 6 is provided as said motion conversion mechanism,
The plurality of cylinders are arranged at equal angular intervals along a circumference of a circle around the axis of the shaft,
The motion conversion mechanism has four connection member support portions corresponding to each of the four cylinders, which are arranged at equal angular intervals along a circumference of a circle around the rotation axis of the swash plate. ,
The connecting rod connected to the piston of the corresponding cylinder is connected to each connecting member support portion as the connecting member,
Each swash plate is moved through the connecting rod and the connecting member support portion such that the phase of each piston is delayed by π / 2 from the piston adjacent to the piston in the third direction. Connected to
The motion conversion mechanism converts a linear reciprocating motion into a rotary motion of the shaft by using each piston as the object, and outputs the displacement.