JPS6126698Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a device for measuring fluid force of a controlled fluid acting on a fluid control valve.

(Prior Art) It is generally known that in a valve that opens, closes, or switches a fluid flow path, when the valve is opened and fluid begins to flow, a fluid force acts in a direction to close the valve.

To explain this based on Fig. 1, when the valve is moved from the closed state shown by the imaginary line in Fig. 1 to the valve opening direction (direction shown) shown by the solid line and fluid fl starts flowing, this fluid By valve 1
Fluid force acts to push it back in the closing direction (leftward in the figure).

That is, when the outflow hole P2 is opened by the movement of the valve 1, the fluid f flowing in from the inflow hole P1
is discharged from the outflow hole P2 through the recess 1A of the valve 1. At this time, the flow velocity of the fluid f is faster near the wall surface 1b of the valve 1 than near the wall surface 1a. Therefore, according to Bernoulli's theorem, when we compare the fluid force F1 acting on the wall 1a and the fluid force F2 acting on the wall 1b, F1
>F2. Therefore, valve 1 has F(F1-
A force F2) (fluid force) acts to move the valve 1 to the left in FIG.

As described above, the fluid force of the controlled fluid acts on the valve 1 as an interference force.

By the way, power steering devices for vehicles usually use a spool valve in the hydraulic circuit, but for example, if the axial force (fluid force) acting on the spool valve is large, the power steering characteristics will be disturbed accordingly. Therefore, when designing a power steering device, it is necessary to know in advance the fluid force acting on this spool valve.

However, in the conventional measurement method, the fluid force was measured after installing the valve in the place where it would actually be used (for example, in a power steering system, the rotation angle of the valve was measured on the shaft on the handle side). A measuring device for measuring rotational torque was attached to the valve, and the fluid force applied to the valve was measured by manually turning the handle and measuring how much rotational torque was applied to the shaft when the handle was turned by a predetermined angle. ) Measured values must be corrected in consideration of play, friction, gear ratio, etc. of the rotation transmission system (for example, rack and pinion or normal gear mechanism) between the shaft on the handle side and the valve. However, there are problems in terms of reliability, reproducibility, and accuracy.
A sufficient analysis could not be performed.

(Purpose of the invention) Therefore, it is an object of the present invention to be able to detect only the fluid force of the controlled fluid acting on the valve, and to be able to accurately grasp this in correspondence with the displacement position of the valve.

(Structure of the invention) The structure of the invention to achieve the above object is that a valve for fluid control is housed in a valve housing equipped with a flow path system for the fluid to be controlled, such as a pump port, a reservoir port, and an outflow port. A fluid force measuring device consisting of an elastic member to which a strain gauge is attached to a valve displacement member that can be displaced by an arbitrary amount in the same direction as the operating direction of the valve and can be fixed at an arbitrary displacement position. a mechanism that connects the valve via the valve and measures the amount of displacement of the valve displacement member; and a mechanism that measures the force that displaces the valve relative to the valve displacement member as the amount of strain deformation of the elastic member. That's what I prepared for.

(Function) Since it is an independently configured measurement device, the influence of other transmission systems can be eliminated.

By fixing the valve displacement member, the driving force for operating the valve is excluded from the measurement target, and only the fluid force of the controlled fluid can be detected.

Understand that the amount of displacement of the valve displacement member is the original displacement amount of the valve, and replace the force that displaces the valve relative to the valve displacement member with the amount of strain deformation of the elastic material. Since it is grasped as the fluid force of the controlled fluid acting on it, it is possible to accurately grasp the correspondence between the displacement amount of the valve and the fluid force.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. First, in FIG. 2 showing the first embodiment of the fluid force measuring device, a valve housing 2 has a pump port 3 connected to an oil pump (not shown) for inflowing fluid, and a pump port 3 connected to an oil pump (not shown) for introducing fluid into an oil tank (not shown). A reservoir port 4 for returning fluid, and a first outflow port 5 and a second outflow port 6 for outflowing fluid to a hydraulic cylinder (not shown) or the like are provided. Further, this valve housing 2 is provided with a valve sleeve 7. However, this valve sleeve 7 is the valve housing 2 in this example.
Although it is formed integrally with the above, it may be formed separately.

A spool valve 8 is inserted into the valve housing 2, and its left end is connected to a load cell 10 via a fixture 9.

Reference numeral 11 denotes a dummy shaft, which is provided as a substitute for an input shaft in a normal power steering device or the like. This dummy shaft 11 is screwed onto a lid 12 at the right end of the valve housing 2.

A guide plate 13 serves as a guide for the fixture 9, and is interposed between the valve housing 2 and a base 14 provided on the left side thereof. O1
is an O-ring interposed between the valve housing 2 and the base 14.

Next, the displacement mechanism, measurement mechanism, and fluid force measurement mechanism, which are the main parts of the present invention, will be explained.

The load cell 10 is formed in a ring shape, and strain gauges 15,
15 are attached facing each other. This becomes the fluid force measurement mechanism in this example.

A cylindrical communication member 16 is attached to the left end of the load cell 10 in the drawing with a nut N, and is inserted into a hole 14a provided in the base 14 so as to be movable forward and backward. An O-ring O2 is provided between the communication member 16 and the inner peripheral surface of the hole 14a.

A cylindrical threaded rod 17 is connected to the communication member 16, and is screwed into a threaded portion 14b formed on the left side of the hole 14a. And this screw rod 1
A handle 18 is fixed to the left end of 7 with a nut N. Therefore, when the handle 18 is rotated, the threaded rod 17 is moved forward and backward in the left and right directions in the drawing. In addition, the above-mentioned handle 18 and threaded rod 17
The displacement mechanism is mainly composed of. Also,
In this example, the fixture 9 and the spool valve 8 are connected via the bearing B, so the handle 18
Since the rotation when the handle 18 is turned is absorbed by this part, the spool valve 8 does not rotate when the handle 18 is turned.

A differential transformer 19 serves as a measuring mechanism in this example for measuring the amount of displacement of the handle 18 in the axial direction.

Next, the action and effect will be explained. first,
The spool valve 8 to be measured is set inside the valve sleeve 7. After the spool valve 8 is attached to the fixture 9, the lid 12 is used to cover the valve housing 2 from the right side in the figure. This set completion state is the state shown in FIG.

The spool valve 8 set in the embodiment shown in FIG. Ports P1, P4 and P3, P5 for flowing oil from the outside to the inside
are installed opposite each other.

On the other hand, the valve housing 2 is formed with grooves M1 to M4 that are compatible with the ports P1 to P5 formed in the spool valve 8. Groove M3 among these grooves M1 to M4 is the second outflow port 6.
The groove M4 communicates with the first outflow port 5.

In the embodiment shown in FIG. 2, the grooves M1 to M4 formed in the valve housing 2 are pre-formed at positions that can fit the spool valve 8, so other types of spool valves 8 can be measured. When attempting to do so (if the external shape is different or the position of the oil groove etc. is different), the valve housing 2 must of course be replaced with one that can fit it. Therefore, a plurality of different spool valves 8
When a measurement of 1 is expected, it is necessary to prepare in advance a valve housing 2 that is compatible with the measurement. (Or a plurality of measuring devices may be prepared in advance.) Next, a specific measuring method will be explained. When the spool valve 8 is set in the valve housing 2, it is first adjusted to a neutral position. This is adjusted because when the handle 18 is rotated, the threaded rod 17 moves forward and backward due to the worm action of the threaded rod 17.

In this state, when fluid starts to flow from pump port 3, the liquid first enters port P2 and groove M1.
and port P1, groove M2 and port P3, groove M3 and port P4, and groove M4 and port P5. The oil is circulated from the reservoir port 4 to an oil tank (not shown) through a gap 9. Therefore, no fluid flows into or out of the first outflow port 5 and the second outflow port 6.

Next, when the handle 18 is rotated to displace (move) the threaded rod 17 in either the left or right direction in the drawing, the spool valve 8 connected via the load cell 10 and the fixture 9 is moved to the threaded rod 17. and move in the same direction.

The amount of displacement of this spool valve 8 is determined by the amount of displacement of the handle 18.
This is detected by the differential transformer 19 because it is the same as the amount of displacement in the horizontal direction shown in the figure. Therefore, it is possible to know how far the spool valve 8 has been moved based on the output value from the differential transformer 19.

On the other hand, by displacing (moving) the spool valve 8, the flow path is switched, and the fluid flows out from either the second outflow port 6 or the first outflow port 5.

For example, when the spool valve 8 is moved to the right in the figure, the port P2 communicates with the grooves M2 and M4, the groove M1 communicates with the port P1, and the groove M3 communicates with the port P4.

On the other hand, communication between port P2 and grooves M1 and M3 is cut off, communication between port P3 and groove M2 is cut off, and communication between port P5 and groove M4 is cut off.

Therefore, fluid flowing in from the pump port 3 passes through the port P2, flows into the groove M4, and flows out from the first outflow port 5.

At this time, the second outflow port 6 communicates with the reservoir port 4 through the groove M3, the port P4, the gap between the dummy shaft 11 and the spool valve 8, the gap between the fixture 9, and the like.

When the spool valve 8 is moved to the right in the drawing, the flow path is secured as described above and the fluid flows.

Next, when the fluid starts flowing in this way, the pressure of the flowing fluid causes the spool valve 8 to
A force (fluid force) acts to displace it in the axial direction. This force is absorbed by the load cell 10 since the threaded rod 17 is fixed. Therefore, the ring-shaped load cell 10 is deformed into an elliptical shape, and tension acts on the strain gauge 15 attached to the outer periphery of the ring-shaped load cell 10.

Then, the resistance value of the strain gauge changes due to the action of this tension, and the fluid force acting on the spool valve 8 can be measured by reading this resistance change of the strain gauge with a meter or the like. An example of this measurement result is shown in FIG. 4.

In the figure, A indicates the fluid force (axial force) that acts on the spool valve 8 when the spool valve 8 is displaced from the neutral position in the left-right direction in FIG.
represents the fluid force (axial force) that acts when the spool valve is returned from the moving end to the neutral position.

The results measured as described above are used as data on the minimum force required to switch the flow path of the spool valve 8, or as data on the force required to maintain the flow path at a certain opening. Used when designing steering devices, etc.

Next, a second embodiment shown in FIG. 3 will be described. In this second embodiment, a rotary valve 8A is installed in place of the spool valve 8 in the first embodiment.

The rotary valve 8A is formed in a cylindrical shape, and an oil groove P6 is formed on the outer circumferential surface of the rotary valve 8A over approximately half the circumference. This rotary valve 8A is a one-way valve that only opens and closes the flow path,
The state shown in FIG. 3 shows a state in which the flow path is open. Note that in order to close the flow path from this state, the rotary valve 8A may be rotated by a predetermined angle around the axis.

Next, the main parts of this second embodiment will be explained. As mentioned above, since the rotary valve 8A is of the type that opens and closes the flow path by rotating it around the axis, a force in the direction of rotation around the axis is applied to the rotary valve 8A by the fluid. The fixture 9 and the connecting member 16 are connected by two threaded load cells 10A, 10A.

In the second embodiment, the rotary valve 8
In order to displace A only in the rotational direction, a connecting rod 17A having no thread is provided instead of the threaded rod 17 in the first embodiment.
A potentiometer 20 is provided in place of the differential transformer 19 in the first embodiment in order to detect the rotation angle of the handle 18. Reference numeral 21 denotes a V-belt.

Note that the reservoir port 4 is a drain in this embodiment. Further, the first outflow port 5 and the second outflow port 6 communicate with each other through a groove M5. Other components that are the same as those in the first embodiment are designated by the same numbers and their explanations will be omitted.

In the case of this second embodiment, when the rotary valve 8A in the closed state (FIG. 3 shows the open state) is rotated by the handle 18, the flow path opens (the rotation angle of the handle 18 is Fluid (sensed by potentiometer 20) flows from pump port 3 through port P6 into groove M5;
It flows out from the first and second outflow ports 5 and 6.

At this time, as this fluid flows, a force is applied to the rotary valve 8 in the rotational direction around the axis, so that the load cell 10A is deformed. Therefore, by reading the resistance value of the strain gauge 15 that changes due to this deformation using a meter or the like, it is possible to measure the fluid force acting on the rotary valve 10A.

In this way, in the second embodiment, the fluid force acting in the rotational direction around the axis of the rotary valve 8A can be measured.

In addition, in this second embodiment, the case where the one-way valve type rotary valve 8A is measured is explained as an example, but it is also possible to measure the fluid force acting on other spool valves such as two-way valves and four-way valves. . However, in this case, the valve sleeve 7 will of course be replaced with one that is compatible with this. Further, the strain gauge used in the first and second embodiments may be replaced with other piezoelectric elements or the like.

(Effects of the invention) The present invention eliminates the influence of other transmission systems that should be linked to the valve and the influence of the driving force for operating the valve, and reduces only the fluid force of the controlled fluid acting on the valve. Can be detected and measured.

Furthermore, it is possible to accurately grasp the correspondence between this fluid force and the amount of displacement of the valve.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the state in which fluid force acts on the valve, Fig. 2 is a side sectional view showing the first embodiment of the invention, and Fig. 3 is a side sectional view showing the second embodiment of the invention. , FIG. 4 is an explanatory diagram showing the measurement results of the amount of movement of the spool valve and the fluid force. 10,10A...load cell, 15...strength gauge, 17...threaded rod, 18...handle,
19...differential transformer, 20...potentiometer.

Claims (1)

[Claims for Utility Model Registration] A fluid force measuring device comprising a fluid control valve housed in a valve housing equipped with a flow path system for controlled fluid such as a pump port, reservoir port, and outflow port, The valve is connected to a valve displacement member which can be displaced by any amount in the same direction as the operating direction of the valve and can be fixed at any displacement position through an elastic member to which a strain gauge is attached, A fluid control valve comprising: a mechanism for measuring the amount of displacement of the valve displacement member; and a mechanism for measuring the force that displaces the valve relative to the valve displacement member as the amount of strain deformation of the elastic member. A fluid force measurement device for a controlled fluid acting on a fluid.