Measurement unit and filter device

Abstract

To enable only attaching a single member to measure a differential pressure, and a degree of deterioration of a liquid targeted for filtering of a filter device.SOLUTION: A measurement unit comprises: a housing that has a column-shape columnar part to be provided in a filter device having a filter medium filtering a liquid; a differential pressure detection unit that is provided in the housing, and detects a differential pressure between a pressure on an upstream side of the filter medium and a pressure on a downstream side thereof; a viscosity sensor that measures viscosity of the liquid; and a temperature sensor that measures a temperature of the liquid. Inside of the columnar part, a hollow part having both ends covered is provided. In the hollow part, the viscosity sensor and temperature sensor are provided, and in the housing, a communication hole is provided that communicates with the hollow part and a space outside of the housing.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a measurement unit and a filter device. [Background technology]

[0002] Patent Document 1 discloses a measurement unit including a substantially columnar case, an antenna section provided in the case and having an antenna capable of communicating with an IC tag, and a sensor provided in the case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-076404 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of liquids filtered by a filter device, particularly oils or fuels containing additives, the additives may deteriorate over time and have a detrimental effect on parts, so there is a demand for measuring the degree of deterioration of the liquid. However, in the invention described in Patent Document 1, although the measurement unit can simultaneously read the IC tag and measure the differential pressure between the pressure on the upstream side and the pressure on the downstream side of the filter medium (hereinafter simply referred to as "differential pressure"), it is not possible to measure the degree of deterioration of the liquid filtered by the filter device.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a measurement unit and a filter device that can measure differential pressure and the degree of deterioration of the liquid to be filtered by the filter device by simply attaching one component. [Means for solving the problem]

[0006] In order to solve the above problems, the measuring unit of the present invention comprises, for example, a housing having a columnar columnar portion that is provided in a filter device having a filter material that filters liquid, a differential pressure detection portion provided in the housing that detects the differential pressure between the pressure upstream and the pressure downstream of the filter material, a viscosity sensor that measures the viscosity of the liquid, and a temperature sensor that measures the temperature of the liquid, wherein a hollow portion with both ends covered is provided inside the columnar portion, the viscosity sensor and the temperature sensor are provided in the hollow portion, and the housing is provided with a communication hole that connects the hollow portion to the space outside the housing.

[0007] In order to solve the above problem, a filter device according to another aspect of the present invention comprises, for example, a filter material for filtering liquid, a filter case in which the filter material is provided, and a measurement unit provided in the filter case, the measurement unit comprising a housing having a columnar portion attached to the filter case, a differential pressure detection unit provided in the housing for detecting the differential pressure between the pressure upstream and the pressure downstream of the filter material, a viscosity sensor provided in the columnar portion for measuring the viscosity of the liquid, and a temperature sensor provided in the columnar portion for measuring the temperature of the liquid, the columnar portion having a hollow portion with both ends covered, the viscosity sensor and the temperature sensor provided in the hollow portion, and the housing having a communication hole that connects the hollow portion to the space outside the housing.

[0008] According to the measurement unit and filter device of the present invention, the columnar portion of the housing is provided in the filter device, and the housing is provided with a differential pressure detection portion that detects the differential pressure between the pressure on the upstream side and the pressure on the downstream side of the filter medium of the filter device. A hollow portion with both ends covered is provided inside the housing, and a viscosity sensor and a temperature sensor are provided in the hollow portion. The housing is provided with a communication hole that communicates the hollow portion with the space outside the housing. This makes it possible to measure the differential pressure and the degree of deterioration (obtained from viscosity and temperature) of the liquid to be filtered by the filter device by simply attaching one member.

[0009] The hollow portion may be columnar and disposed along a central axis of the columnar portion, the differential pressure detection portion may have a spool movably disposed inside the hollow portion, the hollow portion may be divided into a first space and a second space by the spool, the viscosity sensor and the temperature sensor may be disposed in the first space, and the communication hole may have a plurality of first communication holes communicating the first space with a space outside the housing and one second communication hole communicating the second space with a space outside the housing. In this way, by dividing the hollow portion into the first space and the second space by the spool and disposing the temperature sensor and the viscosity sensor in the first space, there is no need to provide a separate space for disposing the temperature sensor and the viscosity sensor, and the housing can be made smaller.

[0010] The first communication hole may be two in number and may be provided along a straight line passing through the central axis when viewed along the central axis, which makes it easier for the liquid to be filtered to flow into and out of the first space.

[0011] The first space may communicate with the upstream side through the first communication hole, and the second space may communicate with the downstream side through the second communication hole, and the spool may have a communication part that communicates the first space with the second space, and the cross-sectional area of ​​the communication part may be smaller than the cross-sectional areas of the first communication hole and the second communication hole. The communication part may be a groove provided on the outer peripheral surface of the spool or a hole provided in the spool. That is, the liquid is guided from the first space to the second space through the communication part. This makes it easier for the hydraulic oil to flow into the first space.

[0012] The hydraulic fluid may include a substrate on which the viscosity sensor and the temperature sensor are provided, the substrate being provided along an end face of the hollow portion, whereby the temperature sensor and the viscosity sensor are exposed in the hollow portion, making it possible to accurately grasp the state of the hydraulic fluid.

[0013] The columnar section may include an antenna capable of communicating with an IC tag, the antenna being provided near a tip of the columnar section, and the differential pressure detector, the viscosity sensor, and the temperature sensor being provided closer to the base of the columnar section than the antenna, thereby allowing the IC tag and the antenna to be closer to each other. Effect of the Invention

[0014] According to the present invention, by simply attaching one member, it is possible to measure the differential pressure and the degree of deterioration of the liquid to be filtered by the filter device. [Brief description of the drawings]

[0015] [Figure 1] 2 is a cross-sectional view showing an outline of a return filter 1 and a measurement unit 2. FIG. [Diagram 2] 2 is a cross-sectional perspective view showing an outline of a return filter 1 and a measurement unit 2. FIG. [Diagram 3] FIG. 2 is a cross-sectional perspective view showing an outline of a measurement unit 2. [Figure 4] 2 is a cross-sectional view showing an outline of a measurement unit 2. FIG. [Diagram 5] 2 is a cross-sectional view showing an outline of a measurement unit 2. FIG. [Figure 6] 2 is a block diagram showing the electrical configuration of a control unit 100. FIG. [Figure 7] FIG. 2 is a perspective view showing an outline of a measurement unit 3. [Figure 8] 2 is a cross-sectional view showing an outline of a measuring unit 3. FIG. [Figure 9] FIG. 2 is a perspective view showing an outline of a measurement unit 4. [Figure 10] FIG. 2 is a cross-sectional view showing an outline of a measurement unit 4. [Figure 11] FIG. 2 is a perspective view showing an outline of a measuring unit 4A. [Figure 12] FIG. 2 is a cross-sectional view showing an outline of a measuring unit 4A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiment, a return filter provided in a tank that stores hydraulic oil will be described as an example, but the filter device of the present invention is not limited to a return filter and can be used as a fuel filter, for example. In addition, in the present embodiment, hydraulic oil will be described as an example of a liquid to be filtered, but the liquid to be filtered is not limited to hydraulic oil and may be various liquids containing additives, such as fuel (petroleum-based, ethanol-based).

[0017] <First embodiment> Fig. 1 is a cross-sectional view showing an outline of the return filter 1 and the measurement unit 2. Fig. 2 is a cross-sectional perspective view showing an outline of the return filter 1 and the measurement unit 2, and shows an enlarged view of the main parts of the return filter 1. In Fig. 1, some of the hatching indicating the cross section is omitted.

[0018] The return filter 1 mainly includes a measurement unit 2, a case 10, a filter element 20, a head 30, and an IC tag 40. The measurement unit 2 is attached to the return filter 1 when in use. The IC tag 40 is a small electronic component that is capable of communicating with an antenna 80 (described in detail later) and that uses radio waves received from the antenna 80 to read and write data in a built-in memory in a non-contact manner. Note that the IC tag 40 is not essential.

[0019] The case 10 is made of a highly corrosion-resistant metal (for example, stainless steel) and is provided so as to protrude from the upper surface of the tank 120 into the inside of the tank 120. Although the case 10 is integrated with the tank 120 in FIG. 1, the case 10 may be formed as a separate part from the tank 120.

[0020] The case 10 has a cylindrical shape with a bottom and an open upper end face. The case 10 is hollow inside, and a head 30 is provided to cover the opening at the upper end. The filter element 20 and the like are provided inside the case 10 and the head 30 (corresponding to the filter case of the present invention).

[0021] The case has a bottom surface 11. An outflow portion 12 is provided so as to penetrate the bottom surface 11. The outflow portion 12 communicates between the internal space of the filter element 20 (space S2) and the external space of the case .

[0022] An inlet portion 13 is provided on a side surface of the case 10. The inlet portion 13 allows the hydraulic oil to flow into a space inside the case 10 and outside the filter element 20 (space S1).

[0023] The filter element 20 is a member having a bottomed tubular shape (here, a bottomed cylindrical shape) and is provided in the internal space formed by the case 10 and the head 30. The filter element 20 mainly has a filter medium 21, an inner cylinder 22, a plate 24, and a plate 25.

[0024] The filter medium 21 is a member for filtering liquid, and is a tubular (here, cylindrical) member having openings at both ends. The filter medium 21 is formed by pleating filter paper made of synthetic resin, paper, etc., and connecting both ends of the pleated filter paper to form a cylinder. An inner tube 22 having holes formed over almost the entire area through which hydraulic oil passes is provided inside the filter medium 21. The inner tube 22 is not essential. An outer tube having holes formed over almost the entire area through which hydraulic oil passes may be provided outside the filter medium 21.

[0025] A resin plate 24 is provided at the upper end of the filter medium 21. The plate 24 covers the upper end surfaces of the filter medium 21 and the inner cylinder 22. The plate 24 and the filter medium 21 are bonded together with an adhesive. As the adhesive, various types of organic adhesives whose main material is resin, rubber, or elastomer can be used.

[0026] The plate 24 mainly has a substantially disk-shaped plate-shaped portion 24a provided along the upper end surface of the filter medium 21 so that the filter medium 21 abuts against the lower side, a cylindrical portion 24b provided on the outer peripheral edge of the plate-shaped portion 24a, a cylindrical portion 24c provided on the inner peripheral edge of the plate-shaped portion 24a, and a convex portion 24d provided on the plate-shaped portion 24a. The cylindrical portion 24b protrudes downward (toward the bottom surface 11) from the plate-shaped portion 24a. The cylindrical portion 24c protrudes upward (toward the opposite side to the filter medium 21) and downward from the plate-shaped portion 24a.

[0027] The protrusion 24d protrudes upward from the plate-like portion 24a. An IC tag 40 is provided on the protrusion 24d.

[0028] A plate 25 is provided at the lower end of the filter medium 21. The plate 25 is a substantially hollow disk-shaped member that covers the filter medium 21 and the lower end surface of the inner cylinder 22. A recess 25a into which the filter medium 21 is inserted is formed on the upper surface of the plate 25. The recess 25a and the filter medium 21 are bonded with an adhesive.

[0029] The outflow portion 12 is inserted into a hole 25b formed in approximately the center of the plate 25. The hole 25b and the outflow portion 12 are sealed by a seal member 91 (for example, an O-ring).

[0030] The head 30 is provided on the case 10 and the plate 24 (here, the cylindrical portion 24c) so as to cover the opening on the upper end surface of the case 10.

[0031] The head 30 is formed of a metal having high corrosion resistance (e.g., stainless steel). The head 30 mainly has a tubular portion 31, a cover 32, and an attachment portion 33. The tubular portion 31 has a cylindrical shape and is fixed to the case 10. The cover 32 is a substantially plate-shaped member and is provided on the upper side (+z side) of the tubular portion 31 so as to cover the hollow portion of the tubular portion 31. The cover 32 is detachable from the tubular portion 31. The cover 32 and the tubular portion 31 are sealed by a seal member (e.g., an O-ring) 93.

[0032] The cover 32 is provided with an attachment portion 33. The attachment portion 33 is a substantially cylindrical member and protrudes downward from the cover 32. A valve 47 is provided at the tip (end on the bottom surface 11 side) of the attachment portion 33. The attachment portion 33 is inserted into the cylindrical portion 24c, and the valve 47 is inserted into the space S2. The attachment portion 33 and the cylindrical portion 24c are sealed by a seal member (e.g., an O-ring) 92. Normally, the valve 47 is closed, but when the filter medium 21 becomes clogged and the pressure inside the case 10 increases, the valve 47 opens and the hydraulic oil flows from the space S1 to the space S2, thereby preventing damage to the return filter 1. The valve 47 is already known, so a description thereof will be omitted.

[0033] The inner diameter of the cylindrical portion 31 is larger than the outer diameter of the plate 24. A hole 31a is formed in a side surface of the cylindrical portion 31, penetrating the side surface. The measurement unit 2 is provided in the cylindrical portion 31 by inserting and fixing the measurement unit 2 into the hole 31a. The cylindrical portion 31 (hole 31a) and the measurement unit 2 are sealed by sealing members (e.g., O-rings) 94, 95.

[0034] The head 30 is provided with a flow path 35 that communicates the space S2 with the hole 31a. The flow path 35 is composed of a hole 33a formed in the attachment portion 33, a hole 32a formed in the cover 32, a space 30a between the cover 32 and the cylindrical portion 31, and a hole 31b formed in the cylindrical portion 31. One end of the flow path 35 (one end of the hole 33a) opens to the space S2, and the other end (one end of the hole 31b) opens to a side surface of the hole 31a.

[0035] Next, the measurement unit 2 will be described. Fig. 3 is a cross-sectional perspective view showing an outline of the measurement unit 2. Fig. 4 is a cross-sectional view showing an outline of the measurement unit 2. In Fig. 4, some of the hatching showing the cross section is omitted.

[0036] The measurement unit 2 mainly includes a housing 50, a differential pressure detection section 60, a sensor section 70, and an antenna 80. Hereinafter, the longitudinal direction of the housing 50 is defined as the z direction, and two directions perpendicular to the z direction are defined as the x direction and the y direction. The x direction and the y direction are perpendicular to each other. However, the antenna 80 is not essential.

[0037] The housing 50 mainly has a case 51, covers 52 and 53, an insert member 54, and a fixing member 55. The case 51 has columnar portions 51v and 51w that are attached to the return filter 1 (see FIG. 2). The columnar portion 51v is inserted into the hole 31a. The columnar portion 51w abuts against the end surface of the cylindrical portion 31 where the hole 31a is provided.

[0038] Covers 52 and 53 have a bottomed cylindrical shape and are provided on both ends of case 51. Cover 52 is provided so as to cover one end (+z side) of case 51, and cover 53 is provided so as to cover the other end (-z side) of case 51. Case 51 and cover 52 are sealed by a seal member (e.g., an O-ring) 96, and case 51 and cover 53 are sealed by a seal member (e.g., an O-ring) 97.

[0039] Holes 51a, 51b, 51c, 51d, grooves 51e, 51f, 51g, and 51k are provided in case 51. Both ends of case 51 are end faces 51m and 51n, respectively.

[0040] Hole 51a, hole 51b, and hole 51d are integrated, and hole 51d opens to end face 51n. Hole 51b is provided closer to end face 51m (+z side) than hole 51d, and hole 51a is provided closer to end face 51m than hole 51b. The diameter of hole 51b is larger than the diameter of hole 51a, and the diameter of hole 51d is larger than the diameter of hole 51b. One end of hole 51c opens to the bottom surface of hole 51b, and the other end opens to end face 51n. Hole 51k opens to end face 51m.

[0041] A groove 51e is provided in the hole 51d. An insert member 54 is provided in the hole 51d and the hole 51b, and a fixing member 55 is provided in the groove 51e. The insert member 54 has a small diameter portion 54a and a large diameter portion 54b having a diameter larger than that of the small diameter portion 54a. The large diameter portion 54b is inserted into the hole 51d, and the small diameter portion 54a is inserted into the hole 51b. By attaching the fixing member 55 to the groove 51e in a state where the insert member 54 is inserted into the hole 51d and the hole 51b, the end of the hole 51a on the end face 51n side is covered. As a result, a hollow portion S3 with both ends covered is provided inside the columnar portions 51v and 51w.

[0042] The hollow portion S3 is provided with a differential pressure detection portion 60. The differential pressure detection portion 60 mainly includes a detection unit 61, a spool 62, a magnet 63, and an elastic member 64.

[0043] The spool 62 has a cylindrical shape and is provided so as to be movable in the z direction inside the hollow portion S3. The outer circumferential surface 62b slides along the hole 51b, whereby the spool 62 moves in the z direction.

[0044] The spool 62 divides the hollow portion S3 into a space S4 (corresponding to the second space of the present invention) and a space S5 (corresponding to the first space of the present invention). One end of a hole 51f (corresponding to the second communication hole of the present invention) opens into the space S4. The case 51 and the insertion member 54 are sealed by a seal member (e.g., an O-ring) 98. Therefore, the hydraulic oil does not flow into the hollow portion S3.

[0045] The hole 51f penetrates the side surface of the columnar portion 51v in the radial direction (here, the x direction), and the other end of the hole 51f opens to the outer peripheral surface of the columnar portion 51v. As a result, the hole 51f communicates with the hole 31b (see Figs. 1 and 2) and the space S4. That is, the space S4 communicates with the space S2 (the downstream side of the filter medium 21) through the hole 51f and one end of the flow path 35 (one end of the hole 33a). In addition, one end of the hole 51g (corresponding to the first communication hole of the present invention, described in detail later) opens to the space S5.

[0046] The elastic member 64 is, for example, a coil spring, one end of which is provided on the spool 62 and the other end of which is provided on the bottom surface of the hole 51b. The elastic member 64 applies a force in the -z direction to the spool 62. The magnet 63 is provided on a surface of the spool 62 facing the bottom surface of the hole 51a, i.e., on the surface of the spool 62 on the end surface 51m side.

[0047] The detection unit 61 is provided inside the hole 51b. The position of the detection unit 61 in the z direction is adjustable.

[0048] The detection unit 61 is provided with a magnetic field detection element 61a. The magnetic field detection element 61a detects changes in the magnetic field generated by the magnet 63. A reed switch, a Hall element, or the like may be used as the magnetic field detection element 61a. The detection result of the magnetic field detection element 61a is output to the outside of the measurement unit 2 via a signal line (not shown). The reed switch and the Hall element are already known, so a description thereof will be omitted.

[0049] Further, a sensor unit 70 is provided in the hollow portion S3 (here, space S5). The sensor unit 70 has a temperature sensor 71 (see FIG. 6, described in detail later) that measures the temperature of the liquid, and a viscosity sensor 72 (see FIG. 6, described in detail later) that measures the viscosity of the liquid. Note that the viscosity sensor 72 can be configured, for example, by a MEMS (Micro Electro Mechanical Systems) disclosed in "Ultra-Small Viscosity Sensor Using MEMS Technology" by Yasuyuki Yamamoto and Sohei Matsumoto (Measurement and Control, Vol. 54, No. 5, May 2015, pp. 351-355).

[0050] In this embodiment, the sensor unit 70 has a substrate on which a temperature sensor 71 and a viscosity sensor 72 are mounted, and the substrate is provided along an end face of the hollow portion S3, i.e., in the insertion member 54. As a result, the temperature sensor 71 and the viscosity sensor 72 are exposed to the space S5. In order to accurately grasp the state of the hydraulic oil, it is desirable to arrange the temperature sensor 71 and the viscosity sensor 72 in the vicinity (for example, adjacent to each other). In addition, the substrate has an actuator (not shown), and the entire substrate or a part of the substrate can vibrate.

[0051] The case 51 is provided with a hole 51c aligned with the central axis ax, and the insertion member 54 is provided with a hole 54c aligned with the central axis ax. The substrate 85 and the sensor unit 70 are electrically connected by wires provided inside the holes 51c and 54c. This allows electricity to be supplied to the temperature sensor 71, the viscosity sensor 72, and the actuator, and the measurement results of the temperature sensor 71 and the viscosity sensor 72 are transmitted to the substrate 85.

[0052] Fig. 5 is a cross-sectional view showing an outline of the measurement unit 2. Fig. 4 and Fig. 5 are different in the angle of the cross section of the measurement unit 2. In Fig. 5, some of the hatching showing the cross section is omitted. In Fig. 5, the spool 62 is located furthest on the -z side.

[0053] One end of the hole 51g opens to the hollow portion S3 formed by the holes 51a and 51d, specifically, to the lower side (-z side) of the spool 62, i.e., the space S5. The other end of the hole 51g opens to the outer circumferential surface of the columnar portion 51v. The hole 51g penetrates the side surface of the columnar portion 51v in the radial direction.

[0054] A cover 53 is provided on the outer side of the columnar portion 51v. A hole 53a is provided in the cover 53, penetrating the side surface of the cover 53 in the radial direction. The hole 53a is in communication with the hole 51g.

[0055] There are two holes 51g and two holes 53a (corresponding to the first communication hole of the present invention), and they are provided along a straight line l1 passing through the central axis ax when viewed along the central axis ax, that is, at 180° intervals. Therefore, two holes 51g and two holes 53a are exposed in FIG. 5. The hydraulic oil is caused to flow into the space S5 through the holes 51g and 53a, and by providing two holes 51g and two holes 53a at 180° intervals, the hydraulic oil can easily flow into and out of the space S5. In addition, the hydraulic oil can be caused to flow and the hydraulic oil present in the space S5 can be replaced sequentially. However, the holes 51g and the holes 53a are not limited to being provided at 180° intervals.

[0056] 2, a gap g is formed between the cover 53 and the hole 31a. Therefore, the space S5 communicates with the space S1 (the upstream side of the filter medium 21) via the hole 51g, the hole 53a, and the gap g.

[0057] Returning to the explanation of Figures 3 to 5, an antenna 80 is provided in the space inside the cover 53, which is the space formed by the cover 53 and the case 51. For this reason, the antenna 80 is provided at the tip of the measurement unit 2, and the differential pressure detection section 60 and the sensor section 70 are provided closer to the base of the case 51 (columnar sections 51v, 51w) than the antenna 80.

[0058] Antenna 80 includes a wiring pattern (antenna coil pattern) formed on one surface (for example, the surface facing cover 53) of antenna 80. Since case 51 and cover 53 are sealed with seal member 97, the antenna 80 does not come into contact with hydraulic oil.

[0059] One end of the antenna wire provided in the hole 51c is connected to the antenna coil pattern, and the other end of the antenna wire is connected to the substrate 85. An IC chip (not shown) and the like are mounted on the substrate 85. When radio waves are received from the IC tag 40, a received signal is generated in the substrate 85 via the antenna wire, and the signal is output to the outside of the measurement unit 2 via a signal line (not shown). Similarly, the measurement results of the temperature sensor 71 and the viscosity sensor 72 are also transmitted to the substrate 85.

[0060] Next, the functions of the return filter 1 and the measurement unit 2 thus configured will be described with reference to FIGS.

[0061] When the engine of the work machine is running, hydraulic oil flows into space S1 inside case 10, as shown by the two-dot chain line arrow in Fig. 1. The hydraulic oil that flows into space S1 flows from the outside to the inside of filter medium 21, and dust and other particles in the hydraulic oil are removed by filter medium 21. The filtered hydraulic oil flows out into space S2. The filtered hydraulic oil then flows out of outlet 12 into the tank.

[0062] When the case 10 is filled with hydraulic oil, the differential pressure detection section 60 of the measurement unit 2 shown in Figures 3 and 4 detects the differential pressure between the pressure on the upstream side (space S1) and the pressure on the downstream side (space S2) of the filter medium 21. The space S2 communicates with the space S4 via the hole 51f and the flow path 35, and the spaces S2 and S4 are on the low pressure side. The space S1 communicates with the space S5 via the hole 51g, the hole 53a, and the gap g, and the spaces S1 and S5 are on the high pressure side.

[0063] When there is no clogging of the filter material 21 and the pressure on the high-pressure side (spaces S1, S5) is low, the spool 62 is pushed toward the insertion member 54 by the biasing force of the elastic member 64, and the magnet 63 is in a position farthest from the bottom surface of the hole 51a.

[0064] When the pressure in space S1 increases due to clogging of filter medium 21, spool 62 moves to the bottom side of hole 50a against the biasing force of elastic member 64. Detection unit 61 detects the change in the magnetic field caused by the movement of magnet 63 and transmits the detection result to an external device. When the detection result shows that the pressure difference between space S1 and space S2 is equal to or greater than a certain level, that is, the clogging of filter medium 21 exceeds a predetermined amount, the external device displays a message encouraging replacement of filter element 20.

[0065] Since the clogging of the filter medium 21 is approximately proportional to the operating time of the filter element 20, the operating time of the filter element 20 can be measured by the IC tag 40, the antenna 80 reads the IC tag 40, and the reading result can be transmitted from the measurement unit 2 to an external device. If a counterfeit product not provided with the IC tag 40 is used as the replaced filter element, the IC tag 40 cannot be read, and the external device can display an error or disable the filter device. Also, for example, by reading the IC tag 40 provided on the replaced filter element 20, the external device can determine that a filter element other than the specified filter element is provided.

[0066] Further, the sensor section 70 of the measurement unit 2 measures the temperature and viscosity of the hydraulic oil. Since the hydraulic oil flows into the space S5 through the holes 51g, 53a, and the gap g, the hydraulic oil comes into contact with the temperature sensor 71 and the viscosity sensor 72. This allows the temperature and viscosity of the hydraulic oil to be measured. Since the holes 51g and the holes 53a are provided in pairs at 180° intervals, the hydraulic oil can easily flow in and out of the space S5.

[0067] In addition, since the substrate of the sensor unit 70 has an actuator (not shown), the substrate vibrates in whole or in part, making it easier for the hydraulic oil to flow into and out of the space S5. Therefore, the hydraulic oil in the space S5 is replaced sequentially, and the temperature and viscosity of the hydraulic oil at the current time can be measured. The measurement results of the temperature sensor 71 and the viscosity sensor 72 are transmitted to the substrate 85.

[0068] The substrate 85 has a control unit 100 that performs processing. Fig. 6 is a block diagram showing the electrical configuration of the control unit 100. Functionally, the control unit 100 mainly has a measurement data acquisition unit 101, a deterioration detection unit 102, and a storage unit 103.

[0069] The functional components of the control unit 100 may be further classified into more components depending on the processing content, or one component may execute the processing of multiple components.

[0070] The measurement data acquiring unit 101 acquires measurement results from the temperature sensor 71 and the viscosity sensor 72 of the sensor unit 70. The measurement results of the temperature sensor 71 and the viscosity sensor 72 are output from the measurement data acquiring unit 101 to the deterioration detecting unit 102.

[0071] The storage unit 103 stores the viscosity of the hydraulic oil at an arbitrary temperature (e.g., 30°C), the relationship between temperature and viscosity, etc. (hereinafter, viscosity information). The deterioration detection unit 102 acquires the viscosity information from the storage unit 103 and detects the degree of deterioration of the hydraulic oil based on this information and the measurement results of the temperature sensor 71 and the viscosity sensor 72. As a characteristic of the hydraulic oil, when an additive added to the hydraulic oil deteriorates, the viscosity increases or decreases even if the temperature of the hydraulic oil is the same (for example, when the defoaming agent deteriorates, the viscosity decreases). Therefore, the deterioration detection unit 102 calculates the viscosity when the temperature is 30°C from the measurement results of the temperature sensor 71 and the viscosity sensor 72, and detects that the hydraulic oil has deteriorated when the calculated viscosity deviates from the normal viscosity stored in the storage unit 103 by a certain value or more. The deterioration detection unit 102 outputs the detection result to the outside of the measurement unit 2 via a signal line not shown.

[0072] For example, the control unit 100 can be configured with an IC mounted on the substrate 85. The processing unit may also be configured with a computer system including an arithmetic unit such as a CPU (Central Processing Unit) for executing information processing, and a storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory). For example, the measurement results of the temperature sensor 71 and the viscosity sensor 72 may be output to an external computer system via a signal line (not shown), and the degree of deterioration of the hydraulic oil may be detected by the computer system.

[0073] According to this embodiment, the measurement unit 2 has a differential pressure detection section 60, a temperature sensor 71 and a viscosity sensor 72, the temperature sensor 71 and the viscosity sensor 72 are provided in the hollow section S3 (space S5), and the hydraulic oil flows into the hollow section S3 (space S5) through holes 51g and 53a. Therefore, by simply installing one measurement unit 2, the differential pressure and the degree of deterioration of the hydraulic oil (determined from the temperature and viscosity) can be measured.

[0074] Furthermore, according to this embodiment, by dividing the hollow portion S3 into spaces S4 and S5 by the spool 62 and providing the temperature sensor 71 and the viscosity sensor 72 in the space S5, there is no need to provide separate space for the temperature sensor 71 and the viscosity sensor 72, and the housing 50 can be made smaller.

[0075] Furthermore, according to this embodiment, the two holes 51g and 53a are provided along the straight line l1, that is, at intervals of 180°, so that the hydraulic oil can easily flow in and out of the space S5.

[0076] Furthermore, according to this embodiment, by providing a substrate having a temperature sensor 71 and a viscosity sensor 72 on the end face (insertion member 54) of space S5, the hydraulic oil that flows into space S5 can be reliably brought into contact with the temperature sensor 71 and the viscosity sensor 72, thereby enabling the temperature and viscosity of the hydraulic oil to be accurately measured.

[0077] Furthermore, according to this embodiment, by providing an actuator on the substrate of the sensor section 70, the substrate can be vibrated and hydraulic oil can flow into the space S5 even if the holes 51g and 53a are narrow. This allows the housing 50, i.e., the measurement unit 2, to be made smaller.

[0078] Furthermore, according to this embodiment, the antenna 80 can be provided at the tip of the measuring unit 2, so that the IC tag 40 and the antenna 80 can be brought closer to each other. This improves the detection accuracy.

[0079] <Second embodiment> In the second embodiment of the present invention, the sensor section 70 has a vibrating substrate, and the holes 51g and 53a are narrowed to reduce the size of the measurement unit 2, but the sensor section 70 does not have to have a vibrating substrate. The measurement unit 3 according to the second embodiment will be described below. Like the measurement unit 2, the measurement unit 3 is attached to the return filter 1 when used. Note that the same parts as those in the first embodiment are given the same reference numerals, and description thereof will be omitted.

[0080] Fig. 7 is a perspective view showing an outline of the measurement unit 3. Fig. 8 is a cross-sectional view showing an outline of the measurement unit 3. Hatching showing the cross section is partially omitted in Fig. 8. The measurement unit 3 mainly has a housing 50A, a differential pressure detection unit 60, a sensor unit 70A, and an antenna 80.

[0081] The housing 50A mainly has a case 51A, covers 52 and 53A, an insert member 54A, and a fixing member 55. The case 51A is substantially cylindrical, and has columnar portions 51x and 51w that are attached to the return filter 1 (see FIG. 2). The columnar portion 51x is inserted into the hole 31a. The columnar portion 51x has a different height (height in the z direction) from the columnar portion 51v, but is otherwise similar.

[0082] Cover 53A has a bottomed cylindrical shape and is provided so as to cover the end on the -z side of case 51A. Cover 53A differs from cover 53 in that it does not have hole 53a and that the height of the side surface is high, but is otherwise similar. Insertion member 54A differs from insertion member 54 in that it is high, but is otherwise similar.

[0083] Case 51A is provided with holes 51a, 51i, 51c, 51d, groove 51e, 51f, and 51h. Both ends of case 51A are end faces 51m and 51n, respectively. Hole 51i is different in depth from hole 51b, but is otherwise similar to hole 51b. Hole 51i is provided with hole 51d and groove 51e.

[0084] The hole 51h (corresponding to the first communication hole of the present invention) is a hole penetrating the side surface of the columnar portion 51x in the radial direction. The hole 51h has a larger cross-sectional area than the hole 51g of the measurement unit 2 (see Figs. 3 to 5, etc.). One end of the hole 51h opens into the hollow portion S3 formed by the holes 51a and 51d, specifically, into the lower side (-z side) of the spool 62, that is, into the space S5. The other end of the hole 51h opens into the outer circumferential surface of the columnar portion 51x. Note that, although the hole 51h is a square hole in Figs. 7 and 8, it is not limited to a square hole and may be, for example, a round hole.

[0085] There are two holes 51h, and they are provided along a straight line l2 passing through the central axis ax when viewed along the central axis ax, that is, at 180° intervals. Therefore, two holes 51h are exposed in FIG. 8. By providing two holes 51h at 180° intervals, the hydraulic oil can easily flow in and out of the space S5. In addition, the hydraulic oil present in the space S5 can be sequentially replaced by the flow of the hydraulic oil.

[0086] The sensor unit 70A has a temperature sensor 71 and a viscosity sensor 72. For example, the sensor unit 70A has a substrate on which the temperature sensor 71 and the viscosity sensor 72 are mounted. Note that the sensor unit 70A differs from the sensor unit 70 in that the substrate does not have an actuator.

[0087] A gap is formed between the housing 50A (the columnar portion 51x and the cover 53A) and the hole 31a. Therefore, the space S5 communicates with the space S1 (the upstream side of the filter medium 21) through the gap and the hole 51h.

[0088] When the engine of the work machine is running, the hydraulic oil flows into the space S1 inside the case 10, flows from the outside to the inside of the filter medium 21, dust and the like in the hydraulic oil is removed by the filter medium 21, and the filtered hydraulic oil flows out into the space S2. The filtered hydraulic oil then flows out from the outlet 12 into the tank. When the case 10 is filled with hydraulic oil, the differential pressure detection section 60 of the measurement unit 3 detects the differential pressure between the pressure on the upstream side (space S1) and the downstream side (space S2) of the filter medium 21.

[0089] Further, the sensor section 70A of the measurement unit 3 measures the temperature and viscosity of the hydraulic oil. The hydraulic oil flows into the space S5 through the gap between the hole 51h and the housing 50A, so that the hydraulic oil comes into contact with the temperature sensor 71 and the viscosity sensor 72. This allows the temperature and viscosity of the hydraulic oil to be measured. Since two holes 51h are provided at intervals of 180°, the hydraulic oil can easily flow into and out of the space S5. Since the cross-sectional area of ​​the hole 51h is large, the hydraulic oil can flow into and out of the space S5 through the hole 51h even if the sensor section 70A does not have an actuator.

[0090] According to this embodiment, the measurement unit 3 has a differential pressure detection section 60, a temperature sensor 71 and a viscosity sensor 72, the temperature sensor 71 and the viscosity sensor 72 are provided in the hollow section S3 (space S5), and the hydraulic oil flows into the hollow section S3 (space S5) through the hole 51h. Therefore, by simply installing one measurement unit 3, the differential pressure and the degree of deterioration of the hydraulic oil can be measured.

[0091] Furthermore, according to this embodiment, by enlarging the hole 51h, the temperature and viscosity of the hydraulic oil can be measured simply by providing the temperature sensor 71 and the viscosity sensor 72 in the space S5. In other words, no actuator is required, and the sensor unit 70A can be simply configured.

[0092] <Third embodiment> In the third embodiment of the present invention, a communication part that communicates between the space S4 and the space S5 is provided on the spool. The measurement unit 4 according to the third embodiment will be described below. The measurement unit 4 is provided on the return filter 1, similar to the measurement unit 2. Note that the same parts as those in the first and second embodiments are given the same reference numerals and description thereof will be omitted.

[0093] Fig. 9 is a perspective view showing an outline of the measurement unit 4. Fig. 10 is a cross-sectional view showing an outline of the measurement unit 4. Hatching showing the cross section is partially omitted in Fig. 10. The measurement unit 4 mainly has a housing 50, a differential pressure detection unit 60A, a sensor unit 70A, and an antenna 80.

[0094] The differential pressure detection section 60A mainly includes a detection unit 61, a spool 62A, a magnet 63, and an elastic member 64.

[0095] The spool 62A has a cylindrical shape and is movably provided inside the hollow portion S3. The spool 62A is different from the spool 62 in that it has a groove 62a, but is otherwise similar to the spool 62.

[0096] Groove 62a (corresponding to a communication portion of the present invention) is provided on outer circumferential surface 62b that abuts against hollow portion S3 of spool 62A. Groove 62a communicates space S4 with space S5 along the extension direction (z direction) of spool 62A. Because the cross-sectional area of ​​groove 62a is smaller than the cross-sectional area of ​​holes 51f and 51g, spool 62A can move in the z direction due to the pressure difference between spaces S4 and S5.

[0097] In this embodiment, the two grooves 62a are provided at intervals of 180°, but the number and arrangement of the grooves 62a are not limited to this.

[0098] When the engine of the work machine is running, the hydraulic oil flows into the space S1 inside the case 10, flows from the outside to the inside of the filter medium 21, and dust and the like in the hydraulic oil is removed by the filter medium 21, and the filtered hydraulic oil flows out into the space S2. The filtered hydraulic oil then flows out from the outlet 12 into the tank. When the case 10 is filled with hydraulic oil, the differential pressure detection section 60A of the measurement unit 4 detects the differential pressure between the pressure on the upstream side (space S1) and the downstream side (space S2) of the filter medium 21. In addition, the sensor section 70A of the measurement unit 4 measures the temperature and viscosity of the hydraulic oil.

[0099] Since the groove 62a that communicates the space S4 and the space S5 is provided in the spool 62A, the hydraulic oil is guided from the space S5 to the space S4 via the groove 62a. Therefore, the hydraulic oil easily flows into the space S5 via the hole 51g and the hole 53a.

[0100] According to this embodiment, the measurement unit 4 has a differential pressure detection section 60A, a temperature sensor 71, and a viscosity sensor 72, the temperature sensor 71 and the viscosity sensor 72 are provided in the hollow section S3 (space S5), and the hydraulic oil flows into the hollow section S3 (space S5) through the hole 51h. Therefore, by simply installing one measurement unit 4, the differential pressure and the degree of deterioration of the hydraulic oil can be measured.

[0101] Furthermore, according to this embodiment, by providing the groove 62a, the temperature and viscosity of the hydraulic oil can be measured simply by providing the temperature sensor 71 and the viscosity sensor 72 in the space S5. That is, an actuator is not required, and the sensor unit 70A can be simply configured. Also, since the groove 62a can be formed simply by cutting the outer circumferential surface of the spool 62A, machining is easy.

[0102] In this embodiment, the groove 62a is provided as a communication part that communicates the space S4 and the space S5, but the communication part is not limited to this. Fig. 11 is a perspective view showing an outline of a measurement unit 4A according to a modified example. Fig. 12 is a cross-sectional view showing an outline of the measurement unit 4A. In Fig. 12, some of the hatching showing the cross section is omitted. The measurement unit 4A mainly has a housing 50, a differential pressure detection unit 60B, a sensor unit 70A, and an antenna 80.

[0103] The differential pressure detection section 60B mainly includes a detection unit 61, a spool 62B, a magnet 63, and an elastic member 64.

[0104] The spool 62B has a cylindrical shape and is provided so as to be movable inside the hollow portion S3. The spool 62B is different from the spool 62 in that it has a hole 62c. The spool 62B is otherwise similar to the spool 62.

[0105] Hole 62c (corresponding to a communication portion of the present invention) is provided inside spool 62B and communicates space S4 with space S5. Since the cross-sectional area of ​​hole 62c is smaller than the cross-sectional area of ​​holes 51f and 51g, spool 62B can move in the z direction due to the pressure difference between spaces S4 and S5.

[0106] The shape of the hole 62c is not limited to this, and it is sufficient that one end of the hole 62c opens to the bottom surface 62d of the spool 62B and the other end opens to the outer circumferential surface 62e, and the hole 62c communicates with the space S4 and the space S5.

[0107] According to this modification, the provision of the hole 62c makes it easier for the hydraulic oil to flow into the space S5. Therefore, an actuator is not required, and the sensor unit 70A can have a simple configuration.

[0108] Furthermore, according to this modification, the length (flow path length), shape, etc. of hole 62c can be easily changed, and flow path control can be appropriately performed. For example, when unfiltered hydraulic oil flows through groove 62a as in spool 62A, the inner wall of hole 51b may be worn down by dust contained in the hydraulic oil when the hydraulic oil is highly contaminated, but this does not occur in this modification in which unfiltered hydraulic oil flows through hole 62c.

[0109] Although the embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes within the scope of the gist of the present invention are also included. For example, the above example has been described in detail to clearly explain the present invention, and is not necessarily limited to those having all of the configurations described. In addition, it is possible to replace a part of the configuration of the embodiment with the configuration of another embodiment, and it is also possible to add, delete, or replace other configurations to the configuration of the embodiment.

[0110] In addition, "approximately" is a concept that includes not only the case of being strictly identical, but also an error or deformation that does not lose the identity. For example, "cylindrical shape" is not limited to the case of being strictly cylindrical, but is a concept that includes, for example, a case that can be regarded as being identical to a cylindrical shape. In addition, for example, when expressing orthogonal, parallel, coincident, etc., it includes not only strictly orthogonal, parallel, coincident, etc., but also approximately parallel, approximately orthogonal, approximately coincident, etc.

[0111] In addition, "vicinity" means including a certain range (which can be determined arbitrarily) near a reference position. For example, in the case of "near an end," it is a concept indicating a certain range of an area near the end, which may or may not include the end. [Explanation of symbols]

[0112] 1: Return filter 2, 3, 4, 4A: Measurement unit 10: Case 11: Bottom 12: Outflow section 13:Inflow part 20: Filter element 21: Filter medium 22: Inner cylinder 24: Plate 24a: Plate-shaped part 24b, 24c: Cylindrical part 24d: Convex part 25: Plate 25a: Recess 25b: hole 30: Head 30a: Space 31: Cylindrical part 31a, 31b: Hole 32: Cover 32a: hole 33: Mounting part 33a: hole 35: Flow path 40: IC tag 47: Valve 50: Housing 50A: Housing 51, 51A: Case 51a, 51b, 51d, 51i, 51k: Holes 51c, 51f, 51g, 51h: Hole 51e: Groove 51m, 51n: End face 51v, 51w, 51x: Column part 52, 53, 53A: Cover 53a: hole 54, 54A: Insertion member 54a: Small diameter part 54b: Large diameter section 54c: hole 55: Fixing member 60, 60A, 60B: Differential pressure detection unit 61:Detection unit 61a: magnetic field detection element 62, 62A, 62B: Spool 62a: Groove 62b, 62e: Outer surface 62c: hole 62d: Bottom 63: Magnet 64: Elastic member 70, 70A: Sensor section 71: Temperature sensor 72: Viscosity sensor 80: Antenna 85: Substrate 91, 92, 93, 94, 95, 96, 97, 98: Sealing material 100: Control unit 101: Measurement data acquisition unit 102: Deterioration detection unit 103: Storage section 120: Tank

Claims

1. a housing having a columnar portion provided in a filter device having a filter material for filtering a liquid; A differential pressure detection unit provided in the housing for detecting a differential pressure between the upstream pressure and the downstream pressure of the filter material; a viscosity sensor for measuring the viscosity of the liquid; a temperature sensor for measuring the temperature of the liquid; Equipped with A hollow portion having both ends covered is provided inside the columnar portion, the viscosity sensor and the temperature sensor are provided in the hollow portion, The housing has a communication hole that connects the hollow portion to the space outside the housing. A measuring unit characterized by:

2. the hollow portion is columnar and is provided along a central axis of the columnar portion, the differential pressure detection unit has a spool movably provided inside the hollow portion, The hollow portion is divided into a first space and a second space by the spool, The viscosity sensor and the temperature sensor are provided in the first space, The communication holes include a plurality of first communication holes that communicate the first space with a space outside the housing, and one second communication hole that communicates the second space with a space outside the housing.

2. The measuring unit according to claim 1.

3. The first communication holes are two in number and are arranged along a straight line passing through the central axis when viewed along the central axis.

3. The measuring unit according to claim 2.

4. the first space communicates with the upstream side via the first communication hole, the second space communicates with the downstream side via the second communication hole, the spool has a communication portion that communicates the first space with the second space, The cross-sectional area of ​​the communication portion is smaller than the cross-sectional areas of the first communication hole and the second communication hole.

4. The measuring unit according to claim 2 or 3.

5. The communication portion is a groove provided on the outer peripheral surface of the spool or a hole provided in the spool.

5. The measuring unit according to claim 4.

6. a substrate on which the viscosity sensor and the temperature sensor are provided, The substrate is provided along the end surface of the hollow portion.

4. The measuring unit according to claim 1, wherein the measuring unit is a measuring device.

7. an antenna provided on the columnar portion and capable of communicating with an IC tag; the antenna is provided near the tip of the columnar portion, The differential pressure detection unit, the viscosity sensor, and the temperature sensor are provided closer to the base of the columnar portion than the antenna.

4. The measuring unit according to claim 1, wherein the measuring unit is a measuring device.

8. A filter medium for filtering liquid; a filter case in which the filter material is provided; a measuring unit provided in the filter case; Equipped with The measuring unit a housing having a columnar post attached to the filter case; A differential pressure detection unit provided in the housing for detecting a differential pressure between the upstream pressure and the downstream pressure of the filter material; a viscosity sensor provided on the columnar portion for measuring the viscosity of the liquid; a temperature sensor provided on the columnar portion for measuring the temperature of the liquid; Equipped with A hollow portion having both ends covered is provided inside the columnar portion, the viscosity sensor and the temperature sensor are provided in the hollow portion, The housing has a communication hole that connects the hollow portion to the space outside the housing. A filter device characterized by:

9. the hollow portion is columnar and is provided along a central axis of the columnar portion, the differential pressure detection unit has a spool movably provided inside the hollow portion, The hollow portion is divided into a first space and a second space by the spool, The viscosity sensor and the temperature sensor are provided in the first space, The communication holes include a plurality of first communication holes that communicate the first space with a space outside the housing, and one second communication hole that communicates the second space with a space outside the housing.

9. The filter device according to claim 8.

10. The first communication holes are two in number and are arranged along a straight line passing through the central axis when viewed along the central axis.

10. The filter device according to claim 9.

11. the first space communicates with the upstream side via the first communication hole, the second space communicates with the downstream side via the second communication hole, the spool has a communication portion that communicates the first space with the second space, The cross-sectional area of ​​the communication portion is smaller than the cross-sectional areas of the first communication hole and the second communication hole.

11. The filter device according to claim 9 or 10.

12. The communication portion is a groove provided on the outer peripheral surface of the spool or a hole provided in the spool.

12. The filter device according to claim 11.

13. a substrate on which the viscosity sensor and the temperature sensor are provided, The substrate is provided along the end surface of the hollow portion.

11. A filter device according to any one of claims 8 to 10.

14. An upper plate provided to cover the upper end surface of the filter material; an IC tag provided on the upper plate, the measurement unit has an antenna capable of communicating with an IC tag, the antenna is provided near the tip of the columnar portion, The columnar portion is provided on the filter case so that the antenna is located inside the filter case.

11. A filter device according to any one of claims 8 to 10.

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