Production method and production apparatus for magnetorheological fluid device

Abstract

Provided are a production method and a production apparatus for a magnetorheological fluid device capable of improving the magnetic particle content within a predetermined error range when the magnetic particle content of the magnetorheological fluid supplied to the constituent members of the device before being filled with the magnetorheological fluid is outside the predetermined error range with respect to a specified value. 【Solution means】The production method of the magnetorheological fluid device includes a supply step of supplying a predetermined amount of magnetorheological fluid from a container 20 to a constituent member 10a, a measurement step of measuring the weight of the constituent member 10a supplied with the magnetorheological fluid, a determination step of determining whether the weight or the density of the magnetorheological fluid calculated based on the weight is within a predetermined error range with respect to a specified value, and supplying a dispersion medium or magnetic particles contained in the magnetorheological fluid, or a magnetorheological fluid having a density different from that of the magnetorheological fluid, to the constituent member 10a determined to have a weight or density outside the error range, and a density improvement step of bringing the density of the magnetorheological fluid supplied to the constituent member 10a closer to the specified value.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for producing a magnetorheological fluid device configured such that a magnetorheological fluid is interposed between members and a force corresponding to the strength of a magnetic field applied to the magnetorheological fluid is transmitted between the members.

Background Art

[0002] A magnetorheological fluid (hereinafter also referred to as "MRF") is a functional fluid whose viscosity changes according to the strength of an applied magnetic field. According to a magnetorheological fluid device (hereinafter also referred to as "MRF device") using this MRF, various operations, controls, etc. that are difficult to achieve with devices that do not use MRF can be realized. Note that, for example, the one disclosed in Patent Document 1 can be exemplified as the MRF device.

[0003] MRF is a fluid in which magnetic particles such as iron are dispersed in a dispersion medium such as oil. Even when a magnetic field of the same strength is applied, the higher the proportion of magnetic particles contained in the MRF, the higher the viscosity exhibited, and the lower the proportion of magnetic particles contained in the MRF, the lower the viscosity exhibited. Therefore, in order for the MRF device to exhibit the designed performance, it is important to adjust the proportion of magnetic particles (hereinafter also referred to as "magnetic particle content") in the MRF used in the MRF device to a predetermined value.

[0004] Generally, when a user of an MRF device obtains MRF, they purchase a fixed quantity (e.g., 300 ml, 500 ml, 1000 ml, etc.) of MRF contained in a container. If the MRF device is small and the amount of MRF used for the MRF device is extremely small (e.g., several ml or less), the MRF can be efficiently filled into the MRF device by using a dispenser. When using the dispenser, the obtained MRF is transferred from its container to the syringe of the dispenser for use. Then, by pressurizing the inside of the syringe by the function of the dispenser, the MRF is quantitatively discharged from the discharge port at the lower part of the syringe and filled into the MRF device. Note that dispensers that can be used in this way are disclosed in Patent Documents 2 to 4 and the like. Also, the container may be used as the syringe of the dispenser.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0006] In an MRF device configured such that MRF is interposed between members and a force corresponding to the strength of the magnetic field applied to the MRF is transmitted between the members, since a force corresponding to the viscosity of the MRF is transmitted between the members, if there is variation (error) in the state of the MRF filled in the MRF device (the ratio of magnetic particles contained in the MRF, the particle size distribution of the magnetic particles contained in the MRF), variation also occurs in the force transmitted between the members of the MRF device. In order for the MRF device to exhibit the performance as designed, it is required to make the state of the MRF filled in each MRF device uniform.

[0007] The force transmitted between the members of the MRF device is most affected by the proportion of magnetic particles in the MRF. Due to the nature of the MRF, the magnetic particles contained in the MRF and the dispersion medium do not completely mix. And the magnetic particles contained in the MRF have a particle size distribution. Therefore, in the container, due to aggregation or sedimentation of the magnetic particles, etc., the dispersion state of the magnetic particles may vary depending on the location in the container.

[0008] When the MRF device is small and the amount of MRF used is extremely small (for example, several ml or less), a part of the MRF in the syringe (container) is supplied to the MRF device by a dispenser for filling. However, if the dispersion state of the magnetic particles in the syringe is different, the magnetic particle content in the MRF supplied to the MRF device may deviate significantly from the magnetic particle content in the MRF originally in the syringe.

[0009] Thus, in the case of a small MRF device that requires only an extremely small amount of MRF, even if the magnetic particle content in the MRF in the syringe matches the specified value recommended by the manufacturer of the small MRF device, the magnetic particle content in the MRF actually supplied to the small MRF device may deviate significantly from the above-specified value, and there is a possibility that the proportion (magnetic particle content) of the magnetic particles contained in the MRF supplied to the MRF device varies. If so, the MRF device may not be able to exhibit its original performance.

[0010] In order to manage the state of the MRF supplied to the MRF device, it is important to manage the magnetic particle content in the MRF. A certain amount (volume) of MRF is supplied to each MRF device. If there is variation in the magnetic particle content in the MRF, there will also be variation in the weight of the certain amount of MRF supplied to the MRF device. Therefore, it is conceivable to manage the magnetic particle content in the MRF based on the variation in the weight of the certain amount of MRF supplied to and filled in the MRF device.

[0011] In this case, MRF devices with a magnetic particle content in the filled MRF within a predetermined error range are sent to the next process, and MRF devices with a magnetic particle content in the filled MRF outside the predetermined error range are to be excluded from the production process and the shipping process. And when the proportion of MRF devices excluded from the production process and the shipping process increases, the processing of the excluded MRF devices becomes a problem.

[0012] The present invention was devised in view of the above circumstances, and when the magnetic particle content of the magnetorheological fluid supplied to the constituent members of the device before the magnetorheological fluid is filled is outside a predetermined error range with respect to a specified value, it is possible to improve the magnetic particle content within the predetermined error range. An object of the present invention is to provide a method for producing a magnetorheological fluid device and a production apparatus therefor.

Means for Solving the Problems

[0013] A method for producing a magnetorheological fluid device according to a first aspect of the present invention is a method for producing a magnetorheological fluid device configured such that a magnetorheological fluid is interposed between members and a force corresponding to the strength of a magnetic field applied to the magnetorheological fluid is transmitted between the members. The method includes: a supply step of supplying a predetermined amount of the magnetorheological fluid from a container containing the magnetorheological fluid to a constituent member of a device that is a part of the magnetorheological fluid device excluding the magnetorheological fluid from the magnetorheological fluid device; a measurement step of measuring the weight of the constituent member supplied with the magnetorheological fluid; a determination step of determining whether the measured weight or the density of the magnetorheological fluid calculated based on the measured weight is within a predetermined error range with respect to a specified value; and a density improvement step of bringing the density of the magnetorheological fluid supplied to the constituent member closer to the specified value by supplying only the dispersion medium contained in the magnetorheological fluid, only the magnetic particles contained in the magnetorheological fluid, or a magnetorheological fluid having a density different from that of the magnetorheological fluid supplied in the supply step, to the constituent member determined in the determination step to be outside the predetermined error range with respect to the specified value.

[0014] The production method of the magnetorheological fluid device according to the second aspect of the present invention is as follows in the production method of the magnetorheological fluid device according to the first aspect. In the determination step, it is determined whether the weight or the density that is the object of determination is greater than the upper limit value of a predetermined error range with respect to the specified value. In the determination step, if it is determined that the weight or the density that is the object of determination is greater than the upper limit value of the predetermined error range with respect to the specified value, in the density improvement step, only the dispersion medium contained in the magnetorheological fluid, or a magnetorheological fluid having a density lower than that of the magnetorheological fluid supplied in the supply step, is supplied to the constituent member.

[0015] The production method of the magnetorheological fluid device according to the third aspect of the present invention is as follows in the production method of the magnetorheological fluid device according to the first aspect. In the determination step, it is determined whether the weight or the density that is the object of determination is less than the lower limit value of a predetermined error range with respect to the specified value. In the determination step, if it is determined that the weight or the density that is the object of determination is less than the lower limit value of the predetermined error range with respect to the specified value, in the density improvement step, only the magnetic particles contained in the magnetorheological fluid, or a magnetorheological fluid having a density higher than that of the magnetorheological fluid supplied in the supply step, is supplied to the constituent member.

[0016] According to the production method of the magnetorheological fluid device according to the first to third aspects of the present invention, even if the density of the magnetorheological fluid supplied to the constituent member of the device is outside the predetermined error range with respect to the specified value, the density can be improved so as to approach the specified value later. Since the magnetic particle content of the magnetorheological fluid is correlated with the weight of a predetermined amount of the magnetorheological fluid and the density of the magnetorheological fluid, according to the present invention, when the magnetic particle content of the magnetorheological fluid supplied to the constituent member of the device is outside the predetermined error range with respect to the specified value, it can be said that the magnetic particle content can be improved within the predetermined error range.

[0017] The production method of a magnetorheological fluid device according to a fourth aspect of the present invention is the production method of a magnetorheological fluid device according to any one of the first to third aspects, wherein the device includes, as the constituent members, a rotating plate fixed to a rotating shaft, a first yoke, and a second yoke. In a state where the rotating plate, the first yoke, and the second yoke are assembled to each other, the rotating plate rotates around an axis, the first yoke faces one main surface of the rotating plate with a first gap therebetween, and the second yoke faces the other main surface of the rotating plate with a second gap therebetween. In the supply step, the magnetorheological fluid is supplied from the container containing the magnetorheological fluid to at least one of the first yoke and the second yoke before assembly. In the measurement step, instead of measuring the total weight of the constituent members supplied with the magnetorheological fluid, the weight of the first yoke and / or the second yoke supplied with the magnetorheological fluid is measured. In the density improvement step, for the first yoke and / or the second yoke determined in the determination step not to be within a predetermined error range with respect to the specified value of the weight or density determined in the determination step, only the dispersion medium contained in the magnetorheological fluid, only the magnetic particles contained in the magnetorheological fluid, or a magnetorheological fluid having a density different from that of the magnetorheological fluid supplied in the supply step is supplied, so as to bring the density of the magnetorheological fluid supplied to the first yoke and / or the second yoke closer to the specified value. In the determination step, after determining that the weight or density to be determined is within a predetermined error range with respect to the specified value, or after the density improvement step, an assembly step of assembling the first yoke, the second yoke, the rotating shaft, and the rotating plate is performed.

[0018] The production method of a magnetorheological fluid device according to a fifth aspect of the present invention is the production method of a magnetorheological fluid device according to any one of the first to third aspects, wherein after the density improvement step, the measurement step and the determination step are performed again, and in the determination step performed again, it is determined whether the density of the magnetorheological fluid calculated based on the weight measured in the measurement step after the density improvement step is within a predetermined error range with respect to the specified value.

[0019] The method for producing a magnetorheological fluid device according to the sixth aspect of the present invention is a production device for a magnetorheological fluid device used for implementing the method for producing a magnetorheological fluid device according to any one of the first to third aspects, the supply device for the magnetorheological fluid having the container, a weighing device for measuring the weight of the component member supplied with the magnetorheological fluid, and a density improver supply device for supplying only the dispersion medium contained in the magnetorheological fluid, only the magnetic particles contained in the magnetorheological fluid, or a magnetorheological fluid having a density different from that of the magnetorheological fluid supplied in the supply step, to the component member.

[0020] According to the above production device for a magnetorheological fluid device, the density of the magnetorheological fluid supplied to the component members of the device can be improved later.

Effects of the Invention

[0021] According to the present invention, when the magnetic particle content of the magnetorheological fluid supplied to the component members of the device before being filled with the magnetorheological fluid is outside a predetermined error range with respect to a specified value, the magnetic particle content can be improved within the predetermined error range.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0023] <First Embodiment> Hereinafter, a production method and a production apparatus 1 for a magnetorheological fluid device according to the first embodiment of the present invention will be described. Note that the production method and the production apparatus 1 for the magnetorheological fluid device described in this embodiment and other embodiments relate to a method for steps after a step of supplying magnetorheological fluid to a constituent member of a device that is a part of the magnetorheological fluid device excluding the magnetorheological fluid, and an apparatus used to carry out the method.

[0024] First, the production apparatus 1 used to carry out the production method of the magnetorheological fluid device (MRF device) will be described. As shown in FIGS. 1 and 2, the production apparatus 1 includes an MRF supply device 2, a weighing device 3, a density improvement material supply device 4, and the like.

[0025] In this embodiment, the MRF supply device 2 includes a storage container 5, a stirring device 6, a transfer pipe 7, a container 20, a switching valve 22, a nozzle 23, a flow rate detector 8, a control device 9, and the like. The MRF supply device 2 is not particularly limited as long as it can supply a predetermined amount of MRF to a constituent member 10a of the device (hereinafter also simply referred to as "constituent member 10a") that is a part of the MRF device 10 excluding the MRF.

[0026] The storage container 5 stores the MRF 21 to be supplied to the constituent member 10a. The MRF 21 in the storage container 5 is transferred to the container 20.

[0027] The stirring device 6 is a device for stirring the MRF21 in the storage container 5, and is mainly composed of a stirring blade 61, a shaft 62, a motor 63, etc. The stirring blade 61 is rotatably disposed in the storage container 5 and is rotated by the motor 63 via the shaft 62. In the present embodiment, the driving of the motor 63 is controlled by the control device 9.

[0028] The transfer pipe 7 has a base end portion communicating with the bottom of the storage container 5, and the MRF21 in the storage container 5 is transferred to the container 20 through the transfer pipe 7.

[0029] The container 20 has a syringe 20a having a bottomed cylindrical shape and a piston 20b slidably inserted into the syringe 20a. The syringe 20a can accommodate an amount of MRF21A that can be supplied to a plurality of devices.

[0030] The piston 20b is moved up and down by an actuator 24 which is a piston driving means. The actuator 24 is driven and controlled by the control device 9. When the piston 20b is pulled by the actuator 24 and moved upward with respect to the container 20, the MRF21 is transferred from the storage container 5 into the container 20.

[0031] In the present embodiment, the switching valve 22 is a three-position switching valve. When the valve position of the switching valve 22 is in the first valve position, the transfer pipe 7 and the container 20 are communicated, and the flow path communicating the container 20 and the nozzle 23 is closed. When the valve position of the switching valve 22 is in the second valve position, the container 20 and the nozzle 23 are communicated, and the flow path communicating the transfer pipe 7 and the container 20 is closed. When the valve position of the switching valve 22 is in the third valve position, the flow path communicating the container 20 and the nozzle 23 is closed, and the flow path communicating the transfer pipe 7 and the container 20 is closed. The switching valve 22 is not particularly limited as long as it can switch a flow path such as a three-way cock. It is also possible to use two valves instead of the switching valve. The switching valve 22 is controlled to switch the valve position by a switching valve actuator (not shown) driven based on a command from the control device 9. In the present embodiment, the switching valve 22 is built in the bottom of the container 20.

[0032] The nozzle 23 is attached to the bottom of the container 20. When the MRF 21A is transferred into the container 20 and the switching valve 22 connects the container 20 and the nozzle 23 in communication, and the piston 20b is pushed into the syringe 20a, the MRF 21A in the container 20 is supplied to the component 10a through the nozzle 23. A flow path having a constant cross-sectional area is formed in the nozzle 23.

[0033] The flow rate detector 8 is provided for detecting the flow rate of the MRF passing through the nozzle 23. The amount (volume) of the MRF passing through the nozzle 23 is detected by this flow rate detector 8. In the present embodiment, the flow rate detector 8 transmits information on the flow rate of the MRF passing through the nozzle 23 to the control device 9.

[0034] The control device 9 performs valve position switching control of the switching valve 22, drive control of the actuator 24, drive control of the motor 63, etc. based on various input information.

[0035] It should be noted that the materials of the storage container 5, the transfer pipe 7, the syringe 20a and the piston 20b of the container 20, the stirring blade 61, the shaft 62, etc. are preferably made of non-magnetic materials so as not to affect the magnetic particles in the MRF.

[0036] The weighing device 3 measures the weight of the MRF supplied to the component 10a. In the present embodiment, the weighing device 3 measures, as the weight of the MRF supplied to the component 10a, the weight obtained by subtracting a predetermined weight from the weight of the component 10a to which the MRF is supplied. Here, the predetermined weight is the weight of the component 10a in a state where no MRF is supplied, and is registered in the weighing device 3 in advance. The weight of the component 10a measured individually before supplying the MRF by the weighing device 3 may be used as the predetermined weight. By measuring the predetermined weight individually, the influence of the variation in the weight of the component 10a before MRF supply on the measurement result of the weight of the MRF can be suppressed. The measurement result of the weight is displayed on the display unit 3a of the weighing device 3, and the information on the measurement result of the weight is transmitted to the control device 9.

[0037] The density improver supply device 4 includes a dispersion medium supply device 41 and a magnetic particle supply device 42. The dispersion medium supply device 41 supplies only the dispersion medium 40a contained in the MRF 21 to the constituent member 10a. The magnetic particle supply device 42 supplies only the magnetic particles 40b contained in the MRF 21 to the constituent member 10a. The density improver supply device 4 operates either the dispersion medium supply device 41 or the magnetic particle supply device 42 under the control of the control device 9.

[0038] As shown in FIGS. 1 and 2, the dispersion medium supply device 41 includes a syringe 41a, a piston 41b, an actuator 41c, a nozzle 41d, a valve 41e, and a flow rate detector 41f. The piston 41b is slidably inserted into the syringe 41a. The piston 41b is moved up and down by an actuator 41c which is a piston driving means. The actuator 41c is driven and controlled by the control device 9. The valve 41e is opened and closed by the control device 9, and supplies the dispersion medium 40a contained in the syringe 41a to the constituent member 10a through the nozzle 41d. The flow rate detector 41f transmits information on the flow rate of the dispersion medium 40a passing through the nozzle 41d to the control device 9.

[0039] The magnetic particle supply device 42 includes a container 42a for accommodating the magnetic particles 40b and a valve 42b for opening and closing a magnetic particle discharge port provided at the bottom of the container 42a. The valve 42b is controlled to be opened and closed by a valve actuator (not shown) driven based on a command from the control device 9. When the valve 42b is opened, the magnetic particles 40b in the container 42a are supplied to the constituent member 10a. Note that the control device 9 controls the amount of the magnetic particles 40b supplied from inside the container 42a, for example, by the opening time of the valve 42b or by changing the opening degree of the valve 42b.

[0040] Next, the MRF device 10 will be described. The MRF device 10 is configured such that MRF is interposed between members, and a force corresponding to the strength of the magnetic field applied to the MRF is transmitted between the members. In this specification, the device excluding MRF from the MRF device 10 is simply referred to as the "device". In this embodiment, MRF is supplied to the constituent member 10a of the device. FIG. 3(a) shows the main constituent members 10a of the device, and FIG. 3(b) shows the MRF device 10 in a state where these constituent members 10a are assembled and filled with MRF. As shown in the figure, the device of the MRF device 10 includes, as the constituent member 10a, a first yoke 11, a second yoke 12, a rotating shaft 13, a rotating plate 14, and MRF 21. The first yoke 11 has a first opposing surface 11a that faces one main surface 14a of the rotating plate 14 with a first gap therebetween. The second yoke 12 has a second opposing surface 12a that faces the other main surface 14b of the rotating plate 14 with a second gap therebetween.

[0041] The rotating shaft 13 is rotatably supported about the axis of the MRF device 10 via a bearing 12c press-fitted into a shaft hole 12b formed in the second yoke 12. The rotating plate 14 is, for example, a disk-shaped plate. The rotating plate 14 is fixed to the rotating shaft 13.

[0042] A coil 12d is built into the second yoke 12. The first yoke 11 and the second yoke 12 are each made of a magnetic material. The first yoke 11 and the second yoke 12 are fixed to each other. The first gap and the second gap are filled with MRF 21. The first yoke 11 and the second yoke 12 and the rotating plate 14 transmit torque to each other via the MRF 21. When a current is applied to the coil 12d, a magnetic field is applied to the MRF 21 filled in the first gap and the second gap, and a viscosity corresponding to the current value applied to the coil 12d appears in the MRF 21. Note that the configuration of the MRF device 10 is not limited to the form described in this embodiment, and other configurations of MRF devices may also be used.

[0043] Next, the implementation steps of the production method of the magnetorheological fluid device will be described with reference to FIG. 4.

[0044] First, as the "MRF production process", magnetic particles and a dispersion medium are mixed in a preparation container (not shown), and MRF is produced while measuring the density (volume and weight) so that the magnetic particle content rate thereof becomes a predetermined specified value. Assume that the particle size distribution of the magnetic particles contained in the produced MRF is the same every time. After turning on the power of the control device 9, the produced MRF is transferred to the storage container 5. Note that the control device 9 controls the valve position of the switching valve 22 to the third valve position in the initial state when the power is turned on.

[0045] Next, as the "transfer process", after stirring the MRF 21 in the storage container 5 for a predetermined time, preferably while continuously stirring the MRF 21, the MRF 21 in the storage container 5 is transferred to the container 20. At this time, the amount of the MRF 21 transferred to the container 20 is an amount that can be supplied to a plurality of devices.

[0046] In the present embodiment, when a user performs a predetermined operation (for example, pressing a start button) on the operation unit of the control device 9, the motor 63 of the stirring device 6 rotates, and the MRF 21 in the storage container 5 is stirred by the stirring blade 61 that rotates together with the motor 63, and the magnetic particles are dispersed in the storage container 5. Then, the control device 9 switches the valve position of the switching valve 22 from the third valve position to the first valve position when a predetermined time has elapsed since the start of stirring, to bring the transfer pipe 7 and the container 20 into communication. Subsequently, the control device 9 drives the actuator 24 to raise the piston 20b to transfer the MRF from the storage container 5 to the container 20 through the transfer pipe 7.

[0047] After that, when the piston 20b has risen to a predetermined position and a predetermined amount of MRF has been transferred to the container 20, the control device 9 stops the raising of the piston 20b by the actuator 24, and further switches the valve position of the switching valve 22 from the first valve position to the third valve position to close the flow path communicating the transfer pipe 7 and the container 20. As a result, the transfer of the MRF from the storage container 5 to the container 20 stops.

[0048] Next, as the "supply process", the control device 9 supplies a predetermined amount of the MRF21A in the container 20 to the constituent member 10a (S1). The supply process is carried out a plurality of times each time the transfer process is carried out once. The number of times the supply process is carried out for each constituent member 10a is not particularly limited, and the supply process may be carried out once for each constituent member 10a, or may be carried out a plurality of times for each constituent member 10a.

[0049] In the present embodiment, when a predetermined operation is performed by the user at the operation unit of the control device 9, the control device 9 switches the valve position of the switching valve 22 from the third valve position to the second valve position to put the nozzle 23 and the container 20 in communication with each other. Further, the control device 9 drives the actuator 24 to lower the piston 20b, sends out the MRF21A in the container 20 to the nozzle 23, and supplies it to the constituent member 10a through the nozzle 23. By performing the supply process one or a plurality of times for each constituent member 10a, the MRF of a specified value (specified amount) is supplied. That is, the MRF of the specified value (specified amount) may be supplied by performing the supply process once for each constituent member 10a, or the MRF of the specified value (specified amount) may be supplied by continuously performing the supply process a plurality of times for each constituent member 10a.

[0050] In the present embodiment, the first yoke 11 and the second yoke 12 before assembly among the constituent members 10a are prepared, and the supply process is carried out for the first yoke 11 and the second yoke 12. The constituent member 10a for which the supply process is carried out is not limited to the first yoke 11 and the second yoke 12, and may be at least one of the first yoke 11, the second yoke 12, and the rotating plate 14, and the supply process may be carried out for the rotating plate 14.

[0051] The supply process is performed once for the first yoke 11 and once for the second yoke 12 to supply the required specified amount of MRF 21 to the MRF device 10. The number of times of the supply process to the first yoke 11 and the second yoke 12 is not particularly limited, and the number of times of the supply process for the first yoke 11 and the second yoke 12 may be different. In the present embodiment, the first yoke 11 has a recess for accommodating the second yoke 12, the rotating plate 14, etc., and supplies MRF by discharging it toward the recess. For the second yoke 12, MRF is supplied by discharging MRF toward the second opposing surface 12a. Note that since MRF has high viscosity and the specified amount of MRF discharged toward the second opposing surface 12a is set to be equal to or less than a certain amount, the discharged MRF adheres to the surface of the second yoke 12 and stays on the surface without flowing down.

[0052] In the supply process, when the control device 9 detects, by the flow rate detector 8, that the amount of MRF passing through the nozzle 23 has reached the specified amount, the control device 9 stops the descent of the piston 20b by the actuator 24. Next, the control device 9 switches the valve position of the switching valve 22 from the second valve position to the third valve position to close the flow path communicating the nozzle 23 and the container 20. As a result, the supply of MRF 21A from the container 20 to the first yoke 11 and the second yoke 12 stops.

[0053] However, when continuously supplying MRF 21A to a plurality of components 10a, or when continuously supplying MRF 21A to the same component 10a, after the control device 9 detects, by the flow rate detector 8, that the amount of MRF passing through the nozzle 23 has reached the specified amount, the control device 9 temporarily stops the descent of the piston 20b by the actuator 24, and without switching the valve position of the switching valve 22, the piston 20b may be lowered again until it is detected that the amount of MRF passing through the nozzle 23 has reached the specified amount. In the present embodiment, a specified amount of MRF may be supplied to the first yoke 11, and then, without switching the valve position of the switching valve 22, a specified amount of MRF may be continuously supplied to the second yoke 12.

[0054] After repeating the lowering and temporary stop of the piston 20b such a certain number of times, the control device 9 may switch the valve position of the switching valve 22 to close the flow path communicating the nozzle 23 and the container 20. Note that the amount of the MRF 21A supplied to the component member 10a in one supply step may be an extremely small amount (for example, several ml or less).

[0055] Next, as the "measurement step", the weight of the prescribed amount of the MRF supplied to the component member 10a is measured by the weighing device 3 (S2). The measured weight is displayed on the display unit 3a of the weighing device 3, and the measurement result information is transmitted to the control device 9. In the present embodiment, the weights of the first yoke 11 and the second yoke 12 supplied with the MRF in the supply step and to which the MRF adheres are measured, and the value obtained by subtracting the weights of the first yoke 11 and the second yoke 12 stored as data in the weighing device 3 in advance from the measured weight is the weight of the MRF supplied to the first yoke 11 and the second yoke 12. In the measurement step, it is only necessary to measure the weight of the component member 10a to which the MRF is supplied in the supply step.

[0056] Next, as the "determination step", the control device 9 determines whether the weight of the MRF supplied to the component 10a measured in the measurement step is within a predetermined error range with respect to a predetermined value of the weight of the MRF (S3). In the present embodiment, the determination is made based on the weight of the MRF supplied to the first yoke 11 and the second yoke 12 which are the components 10a. The predetermined value of the weight of the MRF is a value calculated in advance based on the predetermined value of the density of the MRF supplied to the first yoke 11 and the second yoke 12 and the specified amount of the MRF supplied to the component 10a (that is, the predetermined amount × the number of times the supply step is performed). Note that the predetermined value of the density of the MRF supplied to the first yoke 11 and the second yoke 12 and the specified amount of the MRF are both design values determined by the designer or the like of the MRF device 10 so that the MRF device 10 exhibits predetermined performance. In this way, by calculating in advance the predetermined value of the weight of the MRF supplied to the first yoke 11 and the second yoke 12, the magnetic particle content rate contained in the MRF can be managed based on the variation in the weight of the MRF supplied to the first yoke 11 and the second yoke 12. In the determination step, based on the measured weight, the density of the MRF supplied to the first yoke 11 and the second yoke 12 may be calculated, and it may be determined whether it is within a predetermined error range with respect to the predetermined value of the density.

[0057] If the control device 9 determines in the determination step that the measured weight of the MRF is not within the predetermined error range with respect to the predetermined value of the weight of the MRF ( "NO" in S3), it performs a "density improvement step" (S5, S6). In the present embodiment, as the "density improvement step", only the dispersion medium 40a contained in the MRF or only the magnetic particles 40b contained in the MRF are supplied to the first yoke 11 and the second yoke 12 in order to improve the density of the MRF.

[0058] If the control device 9 makes a negative determination in S3 ( "NO" in S3), as a further determination step, it determines whether the measured weight of the MRF is greater than the upper limit value of the predetermined error range or less than the lower limit value of the predetermined error range with respect to the predetermined value of the weight of the MRF (S4).

[0059] When the control device 9 determines that the measured weight of the MRF is greater than the upper limit value of a predetermined error range with respect to the specified value of the weight of the MRF ( "large" in S4), in order to reduce the density of the MRF and make it closer to the specified value, the dispersion medium supply device 41 is operated. In the present embodiment, the dispersion medium supply device 41 supplies the dispersion medium 40a to the first yoke 11 and the second yoke 12 respectively (S5). Therefore, the control device 9 opens the valve 41e, drives the actuator 41c to lower the piston 41b, and supplies the dispersion medium 40a in the syringe 41a to the first yoke 11 and the second yoke 12 respectively through the nozzle 41d. Preferably, the dispersion medium 40a is discharged and supplied toward the MRF supplied in the supply step and adhering to the first yoke 11 and the second yoke 12. When the dispersion medium 40a is supplied to the first yoke 11 and the second yoke 12, the MRF supplied to the first yoke 11 and the second yoke 12 has a reduced density due to the addition of the dispersion medium 40a. The component member 10a for supplying the dispersion medium 40a targets the component member 10a in which the supply step has been carried out.

[0060] The amount of the dispersion medium 40a supplied to the first yoke 11 and the second yoke 12 by the dispersion medium supply device 41 is set by the control device 9 to be an amount such that the density of the MRF supplied to the first yoke 11 and the second yoke 12 is within a predetermined error range with respect to the specified value. For this purpose, for example, the control device 9 calculates the density based on the weight of the MRF measured in the measurement step, and based on the difference between the calculated density value and the specified value of the density, calculates the amount of the dispersion medium 40a required to make the density of the supplied MRF closer to the specified value. Then, the control device 9 supplies the calculated amount of the dispersion medium 40a in the density improvement step. In the present embodiment, the calculated amount of the dispersion medium 40a is equally supplied to the first yoke 11 and the second yoke 12.

[0061] It is also possible to calculate the amount of the dispersion medium 40a supplied by the dispersion medium supply device 41 by other methods. For example, in advance, the supply process and the measurement process are carried out a plurality of times to obtain data on the weights of the MRFs supplied to the first yoke 11 and the second yoke 12, and the weights when the weight of the MRF in the measured data is greater than the upper limit value of a predetermined error range with respect to the specified value are extracted, and the average value of the weights of the MRFs when it is greater than the upper limit value is calculated. Then, based on the calculated average value, the average value of the density of the MRF when it is greater than the upper limit value of the predetermined error range is calculated, and based on the difference between the average value of the density of the MRF when it is greater than the upper limit value and the specified value, the amount of the dispersion medium 40a required to bring the average value of the density of the MRF when it is greater than the upper limit value closer to the specified value is calculated. The amount of the dispersion medium 40a calculated in this way may be set as the amount of the dispersion medium 40a to be supplied in the density improvement process, and the same amount of the dispersion medium 40a may be supplied in each density improvement process.

[0062] Further, in the determination step, when the control device 9 determines that the measured weight of the MRF is less than the lower limit value of a predetermined error range with respect to the specified value of the weight of the MRF ("small" in S4), in order to increase the density of the MRF and bring it closer to the specified value, the magnetic particle supply device 42 is operated to supply magnetic particles 40b to the first yoke 11 and the second yoke 12 respectively (S6). Preferably, the magnetic particles 40b are discharged and supplied toward the MRFs that are supplied in the supply process and adhered to the first yoke 11 and the second yoke 12. The component member 10a for supplying the magnetic particles 40b targets the component member 10a in which the supply process has been carried out.

[0063] The amount of magnetic particles 40b supplied to the first yoke 11 and the second yoke 12 by the magnetic particle supply device 42 is set by the control device 9 to be the amount necessary for the density of the MRF supplied to the first yoke 11 and the second yoke 12 to be within a predetermined error range with respect to a specified value. For this purpose, the control device 9 calculates, based on the difference between the value of the density calculated based on the weight of the MRF measured in the measurement step and the specified value of the density, the amount of magnetic particles 40b necessary to bring the density of the supplied MRF closer to the specified value, and sets this as the amount of magnetic particles 40b to be supplied in the density improvement step. In the present embodiment, the magnetic particles 40b in the amount set in this way are supplied equally to the first yoke 11 and the second yoke 12.

[0064] It is also possible to calculate the amount of magnetic particles 40b supplied by the magnetic particle supply device 42 by other methods. For example, in advance, the supply step and the measurement step are carried out a plurality of times to obtain data on the weight of the MRF supplied to the first yoke 11 and the second yoke 12, the weight when it is smaller than the lower limit value of the predetermined error range with respect to the specified value is extracted from the measured data, and the average value of the weights when it is smaller than the lower limit value is calculated. Then, based on the average value of the weights, the average value of the densities when it is smaller than the lower limit value is calculated, and based on the difference between the average value of the densities when it is smaller than the lower limit value and the specified value, the amount of magnetic particles 40b necessary to bring the average value of the densities when it is smaller than the lower limit value closer to the specified value is calculated. The amount of magnetic particles 40b calculated in this way may be set as the amount of magnetic particles 40b to be supplied in the density improvement step, and the same amount of magnetic particles 40b may be supplied in each density improvement step.

[0065] In S5 or S6 above, after the dispersion medium 40a or the magnetic particles 40b are supplied to the first yoke 11 and the second yoke 12, if the dispersion medium 40a or the magnetic particles 40b overflow from the first yoke 11 or the second yoke 12, the overflowed dispersion medium 40a or magnetic particles 40b can be wiped off or sucked up and processed (S7). This process (S7) is not essential and may be carried out as necessary.

[0066] When the dispersion medium 40a or the magnetic particles 40b are supplied to the first yoke 11 and the second yoke 12 by the density improvement process, the total amount of the MRF supplied to the first yoke 11 and the second yoke 12 may be more than a predetermined amount. Since there is a margin in the space where the MRF is filled in the MRF device 10, even if the amount of the MRF becomes more than the predetermined amount, it has no influence on the performance of the MRF device 10. In particular, for the MRF device 10, it is important to adjust the magnetic particle content rate in the MRF to a predetermined value. Therefore, even if the amount of the MRF is slightly more than the specified value, it is more important to keep the magnetic particle content rate within a predetermined error range with respect to the specified value.

[0067] In the step S3, after determining that the measured weight of the MRF is within a predetermined error range with respect to the specified value of the weight of the MRF ( "Yes" in S3), or after the process of S6, an "assembly process" of assembling the constituent member 10a is carried out (S8 to S12). In the assembly process, a rotating shaft 13 to which the rotating plate 14 is fixed is prepared, and the rotating shaft 13 is assembled to the first yoke 11 (S8). Then, the second yoke 12 is turned upside down and assembled and fixed to the first yoke 11 (S9). Thereafter, the MRF may be settled by rotating the rotating shaft 13 (S10). In particular, in the case of the assembly process after performing S5 or S6, since the state of the MRF is not uniform, it is preferable to perform a process (S10) of settling the MRF before completely assembling the MRF device 10. Thereafter, when a part of the MRF in the MRF device 10 overflows from the gaps of the constituent member 10a, air vent holes provided separately in the constituent member 10a, etc., a process (S11) of removing the overflowed MRF can be performed as necessary. In this way, the MRF device 10 is completed (S12). At this time, in the MRF device 10, the MRF 21 is filled in the first gap and the second gap. S10 and S11 are not essential and may be carried out as necessary, but by carrying out S10 and S11 in the assembly process after performing S5 or S6, the density of the MRF filled in the MRF device 10 can be made to fall within a predetermined error range from the specified value.

[0068] According to the production method of the above magnetorheological fluid device, by measuring and controlling the density of the MRF filled in the MRF device 10 to be within a predetermined error range from the specified value, the variation in the force transmitted between the members of the MRF device can be reduced, and the MRF device 10 is highly likely to exhibit the performance as designed. Note that the particle size distribution of the magnetic particles contained in the MRF filled in the MRF device 10 can also affect the magnitude of the force transmitted between the members of the MRF device. However, when producing the MRF, it is relatively easy to make the particle size distribution of the magnetic particles contained in the MRF constant. Therefore, in this embodiment, it is assumed that the particle size distribution of the magnetic particles contained in the MRF is the same each time.

[0069] And according to the production method and production device 1 of the above magnetorheological fluid device, in the determination step, when it is determined that the weight of the MRF supplied to the first yoke 11 and the second yoke 12 is not within a predetermined error range with respect to the specified value of the weight of the MRF calculated in advance, the weight of the MRF of the MRF device is improved within the error range by the density improvement step, so that it can be used as a product, and the production cost can also be reduced.

[0070] Furthermore, according to the production method and production device 1 of the above magnetorheological fluid device, compared with the case where an error (deviation from the reference value of the force transmitted between the members of the MRF device) is detected in the final inspection of the MRF device 10, the rework is reduced, and the production cost can also be reduced.

[0071] <Second Embodiment> In the first embodiment, in order to improve the density of the MRF supplied to the constituent member 10a in the supply step, only the dispersion medium 40a contained in the MRF or only the magnetic particles contained in the MRF were additionally supplied to the constituent member 10a. However, it is also possible to additionally supply two types of MRFs having different densities from the MRF used in the supply step to the constituent member 10a.

[0072] Next, a production method and a production apparatus 1A for a magnetorheological fluid device according to the second embodiment of the present invention will be described with reference to FIGS. 5 and 6. First, the production apparatus 1A of an MRF device that implements the production method of the magnetorheological fluid device will be described. The production apparatus 1A includes an MRF supply device 2, a weighing device 3, a density improver supply device 4A, and the like. In the following description, when the functions of the members constituting each part perform the same functions as those in the production apparatus 1 described in the first embodiment, even if the shapes and the like are somewhat different, the same reference numerals as those in the first embodiment will be given and the description will be omitted.

[0073] In this embodiment, the MRF supply device 2 and the weighing device 3 have the same configurations as those in the first embodiment. Also, the "MRF production process" and the "transfer process" are carried out in the same manner as in the first embodiment. And the MRF device 10 also uses the same configuration as in the first embodiment.

[0074] The density improver supply device 4A has a first MRF supply device 43 and a second MRF supply device 44. The first MRF supply device 43 supplies an MRF 40c having a lower density (lower magnetic particle content) than the MRF 21A in the container 20 to the component 10a in the density improvement process. The second MRF supply device 44 supplies an MRF 40d having a higher density (higher magnetic particle content) than the MRF 21A in the container 20 to the component 10a. The density improver supply device 4A operates either the first MRF supply device 43 or the second MRF supply device 44 by the control device 9.

[0075] As shown in FIGS. 5 and 6, the first MRF supply device 43 includes a syringe 43a, a piston 43b, an actuator 43c, a nozzle 43d, a valve 43e, and a flow rate detector 43f. The piston 41b is slidably inserted into the syringe 41a. The piston 43b is moved up and down by an actuator 43c which is a piston driving means. The actuator 43c is driven and controlled by the control device 9. The valve 43e is opened and closed by the control device 9, and supplies the low-density MRF 40c accommodated in the syringe 43a to the component member 10a through the nozzle 43d. The flow rate detector 43f transmits information on the flow rate of the low-density MRF 40c that has passed through the nozzle 43d to the control device 9.

[0076] As shown in FIGS. 5 and 6, the second MRF supply device 44 includes a syringe 44a, a piston 44b, an actuator 44c, a nozzle 44d, a valve 44e, and a flow rate detector 44f. The valve 44e is opened and closed by the control device 9, and when the piston 44b is lowered by the actuator 44c, the high-density MRF 40d accommodated in the syringe 44a is supplied to the component member 10a through the nozzle 44d. The flow rate detector 44f transmits information on the flow rate of the high-density MRF 40d that has passed through the nozzle 44d to the control device 9.

[0077] In the present embodiment, in the supply step, when a predetermined amount of the MRF 21A in the container 20 is supplied to the component member 10a, the first yoke 11 before assembly is prepared from the component member 10a, and a predetermined amount of the MRF is supplied only to the first yoke 11. The number of times of the supply step for the first yoke 11 is not particularly limited, and the required amount of the MRF for the MRF device 10 is supplied once or a plurality of times. The component member 10a for which the supply step is carried out is not limited to the first yoke 11, and may be at least one of the first yoke 11, the second yoke 12, and the rotating plate 14, and the supply step may be carried out on the rotating plate 14.

[0078] Next, in the measurement step, the weight of the specified amount of MRF supplied to the first yoke 11 is measured by the weighing device 3 (S2). Then, the value obtained by subtracting the weight of the first yoke 11, which has been stored in the weighing device 3 as data in advance, from the measured weight is the weight of the MRF supplied to the first yoke 11. In the measurement step, it is only necessary to measure the weight of the component member 10a to which the MRF has been supplied in the supply step.

[0079] Next, as the "determination step", the control device 9 determines whether the weight of the MRF supplied to the component member 10a measured in the measurement step, in this embodiment, the amount of MRF supplied to the first yoke 11 of the component member 10a, is within a predetermined error range with respect to the specified value of the weight of the MRF calculated in advance. The specified value of the weight of the MRF is a value calculated in advance based on the specified value of the density of the MRF supplied to the first yoke 11 and the specified amount of the MRF supplied to the first yoke 11 (that is, the specified amount × the number of times the supply step is performed).

[0080] If the control device 9 determines in the determination step that the measured weight of the MRF is not within the predetermined error range with respect to the specified value of the weight of the MRF, the control device 9 performs the "density improvement step". In this embodiment, as the "density improvement step", MRF 40c having a density lower than that of the MRF 21A in the container 20 or MRF 40d having a density higher than that of the MRF 21A in the container 20 is supplied to the first yoke 11.

[0081] When the control device 9 determines that the measured weight of the MRF is greater than the upper limit value of the predetermined error range with respect to the specified value of the weight of the MRF ( "greater" in S4), the control device 9 operates the first MRF supply device 43 to supply MRF 40c having a lower density to the first yoke 11 (S51). Further, when the control device 9 determines that the measured weight of the MRF is less than the lower limit value of the predetermined error range with respect to the specified value of the weight of the MRF ( "less" in S4), the control device 9 operates the second MRF supply device 44 to supply MRF 40c having a lower density to the first yoke 11 (S52). The component member 10a to which the MRF 40c having a lower density or the MRF 40d having a higher density is supplied is the component member 10a for which the supply step has been performed.

[0082] In S51 or S52, the amount of MRF40c with a low density or MRF40d with a high density to be supplied is set by the control device 9 such that the density of the MRF supplied to the first yoke 11 is within a predetermined error range with respect to a specified value. For this purpose, for example, the control device 9 calculates the density based on the weight of the MRF measured in the measurement step, and based on the difference between the calculated density value and the specified density value, calculates the amount of MRF40c with a low density or MRF40d with a high density necessary to bring the density of the supplied MRF closer to the specified value, and sets it as the amount of MRF40c with a low density or MRF40d with a high density to be supplied in the density improvement step. The amount of MRF40c with a low density or MRF40d with a high density set in this way is supplied to the first yoke 11 in the present embodiment.

[0083] As a method for calculating the amount of MRF40c with a low density or MRF40d with a high density to be supplied, other methods may be used. For example, in advance, the supply step and the measurement step are performed multiple times to obtain data on the weight of the MRF supplied to the first yoke 11, the weights when the measured data is greater than the upper limit value of a predetermined error range with respect to the specified value are extracted from the measured data, and the average values of the weights when greater than the upper limit value are calculated respectively. Then, based on the average value of the weights, the average value of the density when greater than the upper limit value of the predetermined error range is calculated, and based on the difference between the average value of the density when greater than the upper limit value and the specified value, the amount of MRF40c with a low density necessary to bring the average value of the density when greater than the upper limit value closer to the specified value is calculated. Similarly, the amount of MRF40d with a high density is also calculated. The amounts of MRF40c with a low density and MRF40d with a high density calculated in this way are set respectively as the amount of MRF40c with a low density and the amount of MRF40d with a high density to be supplied in the density improvement step, and the same amount of dispersion medium 40a may be supplied in each density improvement step. In this case, in the density improvement step, the amounts of MRF40c with a low density and MRF40d with a high density to be supplied are constant amounts.

[0084] In S51 or S52, even if MRF40c with a low density or MRF40d with a high density is supplied, if the density of the MRF supplied to the first yoke 11 cannot be improved within a predetermined error range with respect to the specified value, in this embodiment, as shown in FIG. 7, after the density improvement process, the measurement process and the determination process are performed again.

[0085] In the measurement process performed again after the density improvement process, in the density improvement process, the weight of the first yoke 11 in a state where MRF40c with a low density or MRF40d with a high density is supplied is measured. Then, the value obtained by subtracting the weight of the empty first yoke 11 stored in advance as data from the measured weight is the weight of the MRF supplied to the first yoke 11. The weight of the MRF measured at this time is the total value of the weight of the MRF supplied to the first yoke 11 in the supply process and the weight of MRF40c with a low density or MRF40d with a high density supplied to the first yoke 11 in the density improvement process.

[0086] Next, in the determination process performed again, the control device 9 determines whether the density of the MRF calculated based on the weight of the MRF supplied to the first yoke 11 measured in the measurement process performed again is within a predetermined error range with respect to the specified value (S3). The weight of the MRF for calculating the density uses the value measured in the measurement process, and the volume of the MRF uses the value obtained by adding the volume of MRF40c with a low density or MRF40d with a high density supplied in the density improvement process to the predetermined amount of the MRF first supplied to the first yoke 11. For this purpose, in the density improvement process, the control device 9 adds the flow rate of MRF40c with a low density or the flow rate of MRF40d with a high density transmitted from the flow rate detector 43f or the flow rate detector 44f to the predetermined amount of the MRF. If the control device 9 determines in the determination process that the density of the MRF calculated based on the weight of the MRF supplied to the first yoke 11 is within a predetermined error range with respect to the specified value (''YES'' in S3), then, next, the assembly process is performed. If the control device 9 determines that it is not within the predetermined error range with respect to the specified value (''NO'' in S3), it may be set to perform the density improvement process again.

[0087] In S3, after determining that the measured weight of the MRF is within a predetermined error range with respect to the specified value of the weight of the MRF (i.e., "Yes" in S3), an "assembly process" for assembling the component 10a is performed (S8 to S12). In the assembly process, a rotating shaft 13 with a rotating plate 14 fixed thereto is prepared, and the rotating shaft 13 is assembled to the first yoke 11 (S8). Then, the second yoke 12 is turned upside down and assembled and fixed to the first yoke 11 (S9). Thereafter, the MRF may be adjusted by rotating the rotating shaft 13 (S10). In particular, in the case of the assembly process after performing S51 or S52 and then performing S3 again, since the state of the MRF is not uniform, it is preferable to perform a process (S10) of adjusting the MRF before completely assembling the MRF device 10. Thereafter, if a part of the MRF in the MRF device 10 overflows from the gaps of the component 10a, the air vent holes provided separately in the component 10a, etc., a process (S11) of removing the overflowing MRF can be performed as necessary. In this way, the MRF device 10 is completed (S12). At this time, in the MRF device 10, the MRF 21 is filled in the first gap and the second gap. In the assembly process, if a part of the MRF supplied to the component 10a overflows from the gaps of the component 10a, the air vent holes provided separately in the component 10a, etc., it is possible to remove and process the overflowing MRF as necessary. S10 and S11 are not essential and may be performed as necessary, but by performing S10 and S11 in the assembly process after performing S51 or S52 and then performing S3 again, the density of the MRF filled in the MRF device 10 can be made to fall within a predetermined error range from the specified value.

[0088] According to the production method and production apparatus 1A of the above magnetorheological fluid device, after the density improvement step, the measurement step and the determination step are performed again. Therefore, even if the density improvement step is carried out, the first yoke 11 in which the density of the MRF is not within a predetermined error range with respect to the specified value can be prevented from being directly transferred to the assembly step and used for the assembly of the MRF device 10. And since the density of the MRF supplied to the component 10a of the MRF device 10 is measured and managed so as to be within a predetermined error range from the specified value, the same operational effects as those of the first embodiment are achieved.

[0089] <Third Embodiment> In the production apparatuses 1 and 1A of the first and second embodiments, the MRF is transferred from the storage container 5 to the container 20, and the MRF is supplied from the container 20 to the component 10a. However, the MRF may be directly supplied from the storage container 5 to the component 10a using a piston or the like without passing through the container 20.

[0090] <Fourth Embodiment> In the production apparatuses 1 and 1A of the first and second embodiments, the piston 20b is used as a configuration for transferring the MRF from the storage container 5 to the container 20 and supplying the MRF from the container 20 to the component 10a. However, the present invention is not limited to the piston 20b. When the supply step is performed each time, compressed air may be supplied into the container 20 to send out the MRF in the container 20 from the container 20 to the nozzle 23, and the MRF may be supplied to the component 10a through the nozzle 23.

[0091] <Fifth Embodiment> In the first and second embodiments, the amount (volume) of the MRF sent out from the container 20 to the nozzle 23 is detected by the flow rate detector 8. However, instead of this, it is also possible to use a configuration in which a fixed amount of MRF is supplied to the component 10a each time without measuring the amount (volume) of the MRF using the flow rate detector 8 or the like.

Industrial Applicability

[0092] The present invention can be applied to a production method and a production apparatus of a magnetorheological fluid device that can change the torque transmitted between members by interposing a magnetorheological fluid between members provided to be relatively rotatable and changing the strength of the magnetic field applied to the magnetorheological fluid.

Explanation of Signs

[0093] 1,1A Production apparatus for MRF device 2 Supply device 3 Weighing instrument 4,4A Density improver supply device 40a Dispersing medium 40b Magnetic particles 40c Low-density MRF 40d High-density MRF 41 Dispersing medium supply device 42 Magnetic particle supply device 43 First MRF supply device 44 Second MRF supply device 5 Storage container 6 Stirring device 61 Stirring blade 62 Shaft 63 Motor 7 Transfer pipe 8 Flow rate detector 9 Control device 10 MRF device (magnetorheological fluid device) 10a Component 11 First yoke 12 Second yoke 13 Rotation shaft 14 Rotation plate 20 Container 20a Syringe 20b Piston 21,21A MRF (magnetorheological fluid) 22 Switching valve 23 Nozzle 24 Actuator

Claims

1. A method for producing a magnetorheological fluid device, comprising: interposing a magnetorheological fluid between members; and transmitting a force between the members in accordance with a strength of a magnetic field applied to the magnetorheological fluid, the method comprising the steps of: a supply step of supplying a predetermined amount of the magnetorheological fluid from a container containing the magnetorheological fluid to a component of a device that is a portion of the magnetorheological fluid device excluding the magnetorheological fluid; a measuring step of measuring a weight of the component to which the magnetorheological fluid has been supplied; a determining step of determining whether the measured weight or the density of the magnetorheological fluid calculated based on the measured weight is within a predetermined error range with respect to a specified value; a density improvement step of supplying only a dispersion medium contained in the magnetorheological fluid, only magnetic particles contained in the magnetorheological fluid, or a magnetorheological fluid having a density different from that of the magnetorheological fluid supplied in the supply step to the component member whose weight or density is determined to be not within a predetermined error range from the specified value in the determination step, thereby bringing the density of the magnetorheological fluid supplied to the component member closer to the specified value; Including, The device includes, as the component, The rotor includes a rotating plate fixed to a rotating shaft, a first yoke, and a second yoke. the rotating plate, the first yoke, and the second yoke are configured so that, when assembled together, the rotating plate rotates about an axis, the first yoke faces one main surface of the rotating plate across a first gap, and the second yoke faces the other main surface of the rotating plate across a second gap, In the supplying step, the magnetorheological fluid is supplied from the container containing the magnetorheological fluid to at least one of the first yoke and the second yoke before assembly; In the measuring step, instead of measuring the total weight of the component to which the magnetorheological fluid is supplied, a weight of the first yoke and / or the second yoke to which the magnetorheological fluid is supplied is measured; in the density improving step, to the first yoke and / or the second yoke whose weight or density is determined in the determining step to be not within a predetermined error range with respect to the specified value, only the dispersion medium contained in the magnetorheological fluid, only the magnetic particles contained in the magnetorheological fluid, or a magnetorheological fluid having a density different from that of the magnetorheological fluid supplied in the supplying step is supplied to the first yoke and / or the second yoke, thereby making the density of the magnetorheological fluid supplied to the first yoke and / or the second yoke closer to the specified value; After it is determined in the determination step that the weight or density to be determined is within a predetermined error range with respect to the specified value, or after the density improvement step, an assembly step is carried out in which the first yoke, the second yoke, the rotating shaft, and the rotating plate are assembled.

13. A method for producing a magnetorheological fluid device comprising:

2. 2. A method for producing a magnetorheological fluid device according to claim 1, comprising the steps of: In the determination step, it is determined whether the weight or density being determined is greater than an upper limit of a predetermined error range with respect to the specified value; In the determination step, when it is determined that the weight or density to be determined is greater than an upper limit value of a predetermined error range with respect to the specified value, In the density improving step, only the dispersion medium contained in the magnetorheological fluid or a magnetorheological fluid having a lower density than the magnetorheological fluid supplied in the supplying step is supplied to the component.

13. A method for producing a magnetorheological fluid device comprising:

3. 2. A method for producing a magnetorheological fluid device according to claim 1, comprising the steps of: In the determination step, it is determined whether the weight or density being determined is smaller than a lower limit value of a predetermined error range with respect to the specified value; When it is determined in the determination step that the weight or density being the subject of the determination is smaller than a lower limit value of a predetermined error range with respect to the specified value, In the density improving step, only the magnetic particles contained in the magnetorheological fluid or a magnetorheological fluid having a density higher than that of the magnetorheological fluid supplied in the supplying step is supplied to the component.

13. A method for producing a magnetorheological fluid device comprising:

4. A method for producing a magnetorheological fluid device according to any one of claims 1 to 3, comprising the steps of: After the density improving step, the measuring step and the determining step are carried out again; In the determination step, which is carried out again, it is determined whether or not the density of the magnetorheological fluid calculated based on the weight measured in the measurement step after the density improvement step is within a predetermined error range with respect to the specified value.

13. A method for producing a magnetorheological fluid device comprising:

5. A production apparatus for a magnetorheological fluid device used for carrying out the production method for a magnetorheological fluid device according to any one of claims 1 to 3, comprising: a supply device for the magnetorheological fluid having the container; a weight measuring device for measuring the weight of the component to which the magnetorheological fluid has been supplied; a density improver supplying device for supplying to the component only the dispersion medium contained in the magnetorheological fluid, only the magnetic particles contained in the magnetorheological fluid, or a magnetorheological fluid having a density different from that of the magnetorheological fluid supplied in the supplying step; Equipped with A production device characterized by:

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