JP6972742B2 - Viscosity measurement method and equipment for unvulcanized rubber and flow simulation method for unvulcanized rubber - Google Patents

Description

The present invention relates to a method and apparatus for measuring the viscosity of unvulcanized rubber and a method for simulating the flow of unvulcanized rubber. The present invention relates to a method and an apparatus for measuring the viscosity of unvulcanized rubber, which can quickly grasp a viscosity close to the viscosity of the above, and a flow simulation method of unvulcanized rubber using the grasped viscosity.

Rubber products include products manufactured by extruding unvulcanized rubber into a molding mold using an extruder or injecting it using an injection machine. There is also a rubber product manufactured by vulcanizing a molded body molded using unvulcanized rubber in a vulcanization mold. In the manufacturing process of these rubber products, the unvulcanized rubber flows to become vulcanized rubber molded into a predetermined shape. Therefore, if the viscosity of unvulcanized rubber can be grasped and its fluidity can be predicted, it is useful for confirming the quality of rubber products and improving productivity.

As a method for measuring the viscosity of unvulcanized rubber, a capillary rheometer (thin tube type viscometer), a flat plate type rotational viscometer, and the like are known. However, since these measurement methods are premised on measurement in a laboratory environment, the measurement results are the viscosity of unvulcanized rubber in molds (cavities and flow paths) in the manufacturing process of rubber products and the like. Is far apart.

Although it is a method for measuring the viscosity of a thermoplastic resin instead of unvulverized rubber, a method for measuring the viscosity based on the pressure gradient and the flow rate in the flow path of the mold for injecting the thermoplastic resin has been proposed (Patented). See Document 1). However, the measurement method of this proposal requires two pressure sensors, and it is necessary to secure an installation space for them. In order to improve the measurement accuracy, it is necessary to install the detection positions of the two pressure sensors as far apart as possible. Then, the viscosity cannot be measured unless the thermoplastic resin passes through the detection position of each pressure sensor. Therefore, in order to improve the measurement accuracy, the space required for the measuring device becomes larger and larger.

Tokuhei No. 3-3908 Gazette

An object of the present invention is a method and apparatus for measuring the viscosity of unvulcanized rubber, which can quickly grasp the viscosity close to the viscosity of unvulcanized rubber in the manufacturing process of rubber products, etc., while making the space required for viscosity measurement compact. It is an object of the present invention to provide a flow simulation method of unvulcanized rubber using the grasped viscosity.

In order to achieve the above object, in the measurement of the viscosity of the unvulcanized rubber of the present invention, the unvulcanized rubber injected into the flow path having a certain cross-sectional shape is flowed in a state of being filled in the flow path, and one pressure is applied. The pressure is detected at one detection position in the flow path by a sensor, and the detection position and the tip of the unvulcanized rubber in the flow direction can be calculated based on the detected pressure, the flow rate of the unvulcanized rubber, and the flow rate. It is characterized in that the viscosity of the unvulcanized rubber is calculated based on the distance from the position, the detected pressure, the tip position in the flow direction of the unvulcanized rubber, and the flow rate.

In order to achieve the above object, the unvulcanized rubber viscosity apparatus of the present invention has a flow path having a certain cross-sectional shape, and the unvulcanized rubber is injected into the flow path and flowed in a state of being filled in the flow path. The injection means, one pressure sensor that detects the pressure of the flow path at one detection position of the flow path, the flow rate detecting means that detects the flow rate of the unvulcanized rubber in the flow path, and the above. It has a calculation unit for inputting the detected pressure of the pressure sensor and the detected flow rate of the flow rate detecting means, and has the detected pressure , the detected flow rate, the detected position that can be calculated based on the detected flow rate, and the unvulcanized state. It is characterized in that the viscosity of the unvulcanized rubber is calculated by the calculation unit based on the distance from the tip position of the rubber in the flow direction.

Another untreated rubber viscosity measuring device of the present invention includes a flow path having a constant cross-sectional shape and an extrusion means for injecting untreated rubber into the flow path and causing the flow path to flow in a filled state. , One pressure sensor that detects the pressure of the flow path at one detection position of the flow path, and a tip position detecting means that detects the tip position of the unvulverized rubber in the flow direction in the flow path. It has a speed detecting means for detecting the flow speed of the unvulverized rubber, and a calculation unit for inputting the detection pressure of the pressure sensor, the detection tip position of the tip position detecting means, and the detection speed of the speed detecting means. It is characterized in that the viscosity of the unvulverized rubber is calculated by the calculation unit based on the detection pressure, the detection tip position and the detection speed.

In the flow simulation method of unvulcanized rubber of the present invention, the viscosity calculated by the above-mentioned method for measuring the viscosity of unvulcanized rubber is used as the viscosity of the unvulcanized rubber in the simulation, and the flow of the unvulcanized rubber is used. It is characterized by performing a simulation.

According to the viscosity measuring method and apparatus of the present invention, one pressure sensor may be used in the flow path for measuring the viscosity of unvulcanized rubber, and the pressure may be detected at one detection position. In addition, the flow rate of the unvulcanized rubber, or the tip position and the flow rate of the unvulcanized rubber in the flow direction may be detected. Then, the viscosity close to the viscosity in the manufacturing process of the rubber product or the like can be calculated without significantly separating the pressure detection position and the detection position for detecting other data. Therefore, it is possible to quickly grasp the viscosity of unvulcanized rubber in the manufacturing process of rubber products and the like while making the space required for viscosity measurement compact.

According to the flow simulation method of the unvulcanized rubber of the present invention, the viscosity close to the viscosity of the unvulcanized rubber in the manufacturing process can be grasped. The behavior of unvulcanized rubber can be further approximated to the behavior in the actual manufacturing process.

It is explanatory drawing which illustrates the viscosity measuring apparatus of this invention with a cylinder and a flow path as a cross section. It is explanatory drawing which illustrates the state which the unvulcanized rubber is injected into the flow path of FIG. It is a graph which illustrates the relationship between the flow direction tip position of unvulcanized rubber injected into a flow path, and the pressure of a flow path. It is explanatory drawing which illustrates another embodiment of the viscosity measuring apparatus of this invention with a cylinder and a flow path as a cross section. It is explanatory drawing which illustrates the simulation model.

Hereinafter, the method and apparatus for measuring the viscosity of unvulcanized rubber and the method for simulating the flow of unvulcanized rubber of the present invention will be described based on the embodiments shown in the figure.

The unvulcanized rubber viscosity measuring device 1 (hereinafter referred to as the measuring device 1) of the present invention exemplified in FIGS. 1 and 2 has a flow path 2 having a constant cross-sectional shape and an unvulcanized rubber R in the flow path 2. The injection means 3 for injecting, one pressure sensor 6 for detecting the pressure P in the flow path 2, the flow rate detecting means 7 for detecting the flow rate Q of the unvulcanized rubber R in the flow path 2, and the calculation unit 9. have. In this embodiment, the measuring device 1 further includes temperature sensors 8 (8a, 8b, 8c). The detection data by the pressure sensor 6, the flow rate detecting means 7, and the temperature sensor 8 are input to the calculation unit 9.

The flow path 2 may be a tube or a metal piece such as a mold. The cross-sectional shape of the flow path 2 may be a polygon such as a circle, an ellipse, a triangle, a square, or a pentagon, but a circular cross section generally used in an actual manufacturing process is preferable. The cross-sectional area of the flow path 2 is substantially the same over the entire length and extends straight. The flow path 2 is preferably linear.

The injection means 3 may be injected in a state where the flow path 2 is filled with the unvulcanized rubber R, and for example, an extruder or an injection machine for rubber can be used. In this embodiment, as the injection means 3, the tubular cylinder 4 in which the unvulcanized rubber R is housed, the plunger 5a arranged inside the cylinder 4, and the plunger 5a are injected in the injection direction of the unvulcanized rubber R. An extruder having a drive mechanism 5c and a drive mechanism 5c is used. The inner peripheral surface of the cylindrical portion having a constant inner diameter of the cylinder 4 and the outer peripheral surface of the cylindrical portion having a constant outer diameter of the plunger 5a face each other with almost no gap. The injection means 3 further has a temperature adjusting unit 5b for adjusting the temperature of the unvulcanized rubber R. The operation of the temperature adjusting unit 5b and the driving mechanism 5c is controlled by the control unit 5d.

The pressure sensor 6 detects the pressure in the flow path 2 at one detection position in the flow path. That is, in the present invention, only one pressure sensor 6 is used.

In this embodiment, the plunger 5a is an injection moving portion that moves in the injection direction of the unvulcanized rubber R to inject the unvulcanized rubber R into the flow path 2. Therefore, the flow rate detection sensor 7 detects the amount of movement of the plunger 5a in the injection direction of the unvulcanized rubber R per unit time.

The temperature sensor 8 detects the temperature of the unvulcanized rubber R at each detection position. In this embodiment, a temperature sensor 8a for detecting the temperature of the unvulverized rubber R inside the cylinder 4, a temperature sensor 8b for detecting the temperature at the injection port (starting point of the flow path 2) of the injection means 3, and a pressure. It has a temperature sensor 8c that detects the temperature at a position that has passed the detection position of the sensor 6.

A computer or the like can be used as the calculation unit 9. The pressure P detected by the pressure sensor 6, the flow rate Q detected by the flow rate detecting means 7, and the temperature T detected by the temperature sensor 8 are input to the calculation unit 9. In addition, the calculation unit 9 has a known cross-sectional area of the plunger 5a (inner cross-sectional area of the cylinder 4), a cross-sectional area of the flow path 2, the length of the flow path 2, a pressure sensor 6 and a temperature sensor in the flow path 2. The data of the detection positions of 8b and 8c (distances from the start point of the flow path 2 to the respective detection positions) are input.

The calculation unit 9 calculates the viscosity μ of the unvulcanized rubber R based on the input detection pressure P and the detection flow rate Q. The calculation formula for calculating the viscosity μ of the unvulcanized rubber R by the calculation unit 9 is the following formula (1). This equation (1) is an equation for calculating the pressure loss of the Newtonian fluid in the circular pipe flow path.
Pressure loss ΔP = (8 ・ μ ・ Q ・ L) / (πr ⁴ ) ・ ・ ・ (1)
Here, ΔP = (pressure P ₁ at the start point of the measurement section) − (pressure P ₂ at the end point of the measurement section), L is the length of the measurement section, and r is the radius of the flow path 2.

In the present invention, as illustrated in FIG. 3, at the flow direction tip X ₂ of the unvulcanized rubber R flowing in the flow path 2, the pressure in the measurement section is focused on the fact that _{the pressure P 2 in the flow path 2 is zero.} The magnitude of the loss ΔP is acquired. That is, where the detection pressure P at the detection position X _{1 of the pressure sensor 6 is P 1} , the flow path 2 at the _{tip X 2} in the flow direction of the unvulcanized rubber R flowing through the detection position X ₁ Let the pressure P be P ₂ = 0.

The cylinder 4 and the flow path 2 are continuous, and the unvulcanized rubber R flows through the cylinder 4 and the flow path 2 without interruption. Since the unvulcanized rubber R can be regarded as an incompressible fluid, the flow rate Q of the unvulcanized rubber R is the volume of the section in which the plunger 5a moves inside the cylinder 4 in a unit time. That is, the cross-sectional area of the plunger 5a × the unit time movement amount of the plunger 5a is the flow rate Q. Since the unit-time movement amount of the plunger 5a is detected by the flow rate detecting means 7, and the cross-sectional area of the plunger 5a is known, the flow rate Q is known.

_{The tip position X 2} in the flow direction of the unvulcanized rubber R can be calculated based on the flow rate Q. The volume of the section in which the plunger 5a has moved in the unit time inside the cylinder 4 (flow rate Q) is the same as the volume in which the unvulcanized rubber R has moved in the flow path 2 in the unit time. Then, since the flow rate Q is known and the cross-sectional area of the flow path 2 is known, the tip position X _{2 in} the flow direction of the unvulcanized rubber R flowing in the flow path 2 is known. Therefore, the separation distance between the _{tip position X 2 in the} flow direction and the detection position X ₁ which is the length L of the measurement section of the equation (1) is also known.

The formula (1) is a calculation formula applied to the circular pipe flow path, but when the cross-sectional shape of the flow path 2 is other than a circle, the formula (1) is arranged and used.

Next, a procedure for measuring the viscosity μ of the unvulcanized rubber R according to the present invention will be described.

As illustrated in FIG. 1, the unvulcanized rubber R is housed in the cylinder 4 of the injection means 3. At this time, the unvulcanized rubber R is heated to a predetermined temperature by the temperature control unit 5b. Next, as illustrated in FIG. 2, the plunger 5a is moved forward to inject the unvulcanized rubber R from the cylinder 4 into the flow path 2. The unvulcanized rubber R injected into the flow path 2 flows in a state of being filled in the flow path 2.

After the unvulcanized rubber R _{passes through the detection position X 1} of the pressure sensor 6, the detection pressure P of the pressure sensor 6 is input to the calculation unit 9 at an arbitrary time. Further, at this point, the movement amount of the plunger 5a detected by the flow rate detecting means 7 per unit time is input to the calculation unit 9.

The calculation unit 9 calculates the detected flow rate Q of the unvulcanized rubber R in the flow path 2 based on the input amount of movement of the plunger 5a per unit time and the cross-sectional area of the plunger 5a. _{Further, the detection tip position X 2} in the flow path 2 is calculated based on the detected flow rate Q and the cross-sectional area of the flow path 2. Since detection position X ₁ of the pressure sensor 6 is known, the distance from the starting point X ₀ of the channel 2 to the detection end position X _2, detecting the position of the pressure sensor 6 from the starting point X ₀ of the channel 2 By subtracting the separation distance to X _1, the length L of the measurement section in the equation (1) is calculated.

If the pressure P ₂ of the channel 2 at the detection end position X ₂ of the unvulcanized rubber R is zero, the pressure P ₁ of the flow path 6 of the detection position X ₁ of the pressure sensor 6 and the sensed pressure P, (1 ) The numerical value other than the viscosity μ is found. Therefore, the viscosity μ of the unvulcanized rubber R is calculated by the calculation unit 9 using the known data and the equation (1).

The viscosity μ of the unvulcanized rubber R is highly temperature-dependent. Therefore, the viscosity μ is calculated by the temperature control unit 5b under the condition that the unvulcanized rubber R is changed to various temperatures, and the correlation between the viscosity μ and the temperature is determined for each rubber type of the unvulcanized rubber R. It's good to know.

The embodiment of the measuring device 1 illustrated in FIG. 4 is different from the previous embodiment in that the flow rate detecting means 7 of the previous embodiment is omitted, and the other configurations are the same. _{In this embodiment, the temperature sensors 8b and 8c have a tip position detecting means for detecting the tip position X 2} in the flow direction of the unvulcanized rubber R in the flow path 2 and a velocity detection for detecting the flow velocity V of the unvulcanized rubber R. Make it function as a means.

As illustrated in FIG. 2, when the unvulcanized rubber R is injected from the injection means 3 into the flow path 2, the respective temperature sensors 8b and 8c detect the temperature when the flowing unvulcanized rubber R passes through. T rises sharply. The detection positions (separation distances) of the respective temperature sensors 8b and 8c are known, the time point (time) when the detection temperature T suddenly rises can be grasped, and these data are input to the calculation unit 9. The calculation unit 9 calculates the flow velocity V of the unvulcanized rubber R in the flow path 2 as the detection velocity based on these input data.

In this embodiment, the detection pressure P at the detection position X _{1 of the pressure sensor 6 is P 1} , the detection position of the temperature sensor 8c is the tip position X _{2 in the} flow direction, and the pressure P of the flow path 2 is P ₂ = 0. .. Therefore, the pressure P detected by the pressure sensor 6 at the time when the detection temperature T of the temperature sensor 8c rises sharply (when the unvulcanized rubber R reaches the detection position of the temperature sensor 8c) becomes _{P 1.}

Since the cross-sectional area of the flow path 2 is known, the calculation unit 9 calculates the detected flow rate Q of the unvulcanized rubber R in the flow path 2 based on this data and the calculated detection speed V. Here, since the separation distance between the detection position of the pressure sensor 6 and the temperature sensor 8c is known, this separation distance becomes the length L of the measurement section in the equation (1).

As described above, the numerical values other than the viscosity μ in the equation (1) are found. Therefore, the viscosity μ of the unvulcanized rubber R is calculated by the calculation unit 9 using the known data and the equation (1).

In this embodiment, two temperature sensors 8b and 8c arranged apart from each other function as a tip position detecting means and a speed detecting means, but one temperature sensor 8c and one pressure sensor 6 are used as a tip position detecting means and a speed detecting means. It can also function as a means. _{That is, when the unvulcanized rubber R passes through the detection position X 1} of the pressure sensor 6, the detection pressure P rises sharply. The detection position X ₁ of the pressure sensor 6 is known, and the time point (time) when the detection pressure P suddenly rises can be grasped.

Therefore, the pressure sensor 6 is used instead of one of the temperature sensors 8b described in the embodiment of FIG. 4, and is used in combination with the other temperature sensor 8c. Thereby, the detection tip position X2 and the detection speed V of the unvulcanized rubber R in the flow path 2 can be grasped. Therefore , it is also possible to calculate the viscosity μ of the unvulcanized rubber R.

As described above, according to the present invention, in order to measure the viscosity μ of the unvulcanized rubber R, the pressure is detected at _{one detection position X 1 by using one pressure sensor 6 in the flow path 2.} In the flow path 2, the flow rate Q of the unvulcanized rubber R, or the flow direction tip position X ₂ and the velocity V of the unvulcanized rubber R may be detected. _{Then, the detection position X 1} of the pressure sensor 6 and the detection position for detecting the flow rate Q, the tip position X _{2 in the} flow direction, and the velocity V need not be largely separated from each other. Therefore, the space required for viscosity measurement can be made compact as compared with the case where the pressure gradient ΔP of the flow path 2 is detected by using the two pressure sensors 6.

Further, rubber molding has a significantly slower injection speed and extrusion speed than resin molding. Therefore, when two pressure sensors 6 are used, it takes a considerable amount of time for the flowing unvulcanized rubber R to pass through the detection positions of the two pressure sensors 6. Therefore, it is disadvantageous to quickly measure the viscosity μ of the unvulcanized rubber R, but according to the present invention, the viscosity μ of the unvulcanized rubber R can be quickly grasped while avoiding such a demerit. can do.

In order to grasp the viscosity μ of the unvulcanized rubber R while compacting the space required for viscosity measurement, for example, the detection position X ₁ of the pressure sensor 6 is located as close as possible to the injection port of the injection means 3 (several cm to 10 cm). It is preferable to set it at a position where the flow of the unvulcanized rubber R is stable. Further, the flow rate Q may be such that the unvulcanized rubber R is located _{downstream of the detection position X 1} of the pressure sensor 6 and as close as possible to the detection position X ₁ (position of several cm to 10 cm).

Further, according to the present invention, the viscosity close to the viscosity in the manufacturing process of rubber products and the like is calculated as compared with the conventional existing viscometers such as a capillary rheometer (thin tube type viscometer) and a flat plate type rotational viscometer. It is possible to do. It was confirmed by experiments and simulations that the viscosity μ of the unvulverized rubber R measured by the present invention is closer to the viscosity in the manufacturing process of rubber products, etc. than the viscosity measured by the existing viscometer. ing.

In the flow simulation method of the unvulcanized rubber of the present invention, the viscosity μ of the unvulcanized rubber R calculated as described above is used. In the flow simulation, the unvulcanized rubber R is flowed using a computer in the simulation model 10 as illustrated in FIG. In this embodiment, it is a simulation model 10 for manufacturing a vulcanizing bladder by injecting unvulcanized rubber R from an injection machine 11 into a cavity 14 of a molding mold 13 via a flow path 12. The simulation model 10 may be a two-dimensional model or a three-dimensional model. In addition to the viscosity μ, the shape and temperature data of the molding mold 13 (flow path 12 and cavity 14), injection pressure data, and the like are input to the computer.

The viscosity μ used in the simulation is close to the viscosity of the unvulcanized rubber R in the manufacturing process of a rubber product or the like using the unvulcanized rubber R. Since the viscosity greatly affects the fluidity of the unvulcanized rubber R, the behavior of the unvulcanized rubber R flowed by the simulation model 10 is approximated by the behavior in the actual manufacturing process by using this viscosity μ. be able to.

Since the viscosity of the unvulcanized rubber R is highly temperature-dependent, the viscosity μ calculated under temperature conditions close to the temperature of the unvulcanized rubber R in the actual manufacturing process is used in the flow simulation. The present invention can be used for simulations when manufacturing various rubber products such as tires, hoses, fenders, conveyor belts, rubber members constituting these rubber products, and rubber manufacturing equipment members such as bladder. can.

1 Measuring device 2 Flow path 3 Injection means 4 Cylinder 5a Plunger (injection moving part)
5b Temperature control unit 5c Drive mechanism 5d Control unit 6 Pressure sensor 7 Flow detection means 8a, 8b, 8c Temperature sensor 9 Calculation unit 10 Simulation model 11 Injection machine 12 Flow path 13 Molding mold 14 Cavity R Unvulcanized rubber

Claims (8)

The unvulcanized rubber injected into the flow path having a certain cross-sectional shape is flowed in a state of being filled in the flow path, and the pressure is detected and detected at one detection position of the flow path by one pressure sensor. The distance between the detected position and the tip position in the flow direction of the unvulcanized rubber, which can be calculated based on the pressure, the flow rate of the unvulcanized rubber, and the flow rate, or the detected pressure and the unvulcanized rubber. A method for measuring the viscosity of an unvulcanized rubber, which comprises calculating the viscosity of the unvulcanized rubber based on the tip position in the flow direction and the flow rate of the unvulcanized rubber. The method for measuring the viscosity of unvulcanized rubber according to claim 1, wherein the flow rate is acquired based on the amount of movement of the injection moving portion of the injection means for injecting the unvulcanized rubber into the flow path in the injection direction. Claim 1 or 2 for acquiring the flow direction tip position and flow rate of the unvulcanized rubber based on the longitudinal direction detection position and the detection temperature data in the flow path of the temperature sensor that detects the temperature of the flow path. The method for measuring the viscosity of unvulcanized rubber according to the description. A flow path having a constant cross-sectional shape, an injection means for injecting unvulverized rubber into the flow path and flowing the flow path in a state of being filled in the flow path, and a flow path of the flow path at one detection position of the flow path. A calculation in which one pressure sensor for detecting pressure, a flow rate detecting means for detecting the flow rate of the unvulverized rubber in the flow path, a detection pressure of the pressure sensor, and a detected flow rate of the flow rate detecting means are input. Has a part and
The unvulcanized by the calculation unit based on the detected pressure , the detected flow rate, and the separation distance between the detected position and the tip position of the unvulcanized rubber in the flow direction, which can be calculated based on the detected flow rate. An unvulcanized rubber viscosity measuring device characterized in that the viscosity of the rubber is calculated. A flow path having a constant cross-sectional shape, an extrusion means for injecting unvulverized rubber into the flow path and causing the flow path to flow in a state of being filled in the flow path, and a flow path of the flow path at one detection position of the flow path. One pressure sensor for detecting pressure, a tip position detecting means for detecting the tip position in the flow direction of the unvulture rubber in the flow path, and a speed detecting means for detecting the flow rate of the unvulture rubber. , A calculation unit for inputting the detection pressure of the pressure sensor, the detection tip position of the tip position detecting means, and the detection speed of the speed detecting means.
A viscosity measuring device for unvulcanized rubber, characterized in that the viscosity of the unvulcanized rubber is calculated by the calculation unit based on the detection pressure, the detection tip position, and the detection speed. The viscosity measuring device for unvulcanized rubber according to claim 4, wherein the flow rate is acquired based on the amount of movement of the injection moving portion of the injection means in the injection direction. The fifth aspect of claim 5 is configured in which the flow direction tip position and speed of the unvulcanized rubber are acquired based on the longitudinal direction detection position and the detection temperature of the temperature sensor that detects the temperature of the flow path. The described unvulcanized rubber viscosity measuring device. It is characterized in that the flow simulation of the unvulcanized rubber is performed by using the viscosity calculated by the viscosity measuring method of the unvulcanized rubber according to any one of claims 1 to 3 as the viscosity of the unvulcanized rubber in the simulation. A flow simulation method for unvulcanized rubber.

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