Liquid state sensor, liquid state assessment device, and hydraulic unit

Abstract

A liquid state sensor (1) is attached to the middle of a pipe. The present invention comprises: connection parts (31, 32) having a main flow path (20) that relays a flow path of piping; flow-dividing parts (33a-33c, 34, 11) having a bypass flow path (21) that is branched from the main flow path 20; and a detection unit (13) that detects the color of light transmitted through a liquid flowing through the bypass flow path (21). The flow path cross-section of the bypass flow path (21) is formed to be smaller than the flow path cross-section of the main flow path (20), and the detection unit (13) is attached to the side of the bypass flow path (21).

Description

Liquid state sensor, liquid state determination device, and hydraulic unit

[0001] The disclosed technology relates to a liquid state sensor, a liquid state determination device, and a hydraulic unit.

[0002] Regarding the disclosed technology, Patent Document 1 discloses a lubricating oil deterioration sensor. The lubricating oil deterioration sensor is composed of a white LED, an RGB sensor, etc. Then, the light emitted by the white LED is transmitted through a gap into which the lubricating oil penetrates. By receiving the transmitted light with the RGB sensor, the color of the lubricating oil is detected. The degree of deterioration of the lubricating oil can be determined from the change in the color.

[0003] Specifically, the lubricating oil deterioration sensor has a bolt-like appearance. The white LED and the RGB sensor are arranged at its head. And it is screwed to a partition wall so that the protruding end of its shaft portion contacts the lubricating oil. A prism with a gap of about 1 mm formed is attached to the protruding end of the shaft portion. The prism reflects and bends the emitted light. By doing so, the light passes through the gap.

[0004] WO2012 / 074109 A1

[0005] The lubricating oil deterioration sensor of Patent Document 1 has a complex and delicate structure and is prone to false detection.

[0006] That is, this type of sensor is generally attached to an oil tank that stores lubricating oil. In that case, there is almost no flow of lubricating oil in the oil tank. The lubricating oil deterioration sensor is detected by transmitted light passing through a minute gap. Therefore, if foreign matter enters the gap, the foreign matter stays and accumulates in the gap. Therefore, it is prone to false detection.

[0007] Therefore, this specification discloses a technology that can effectively suppress false detection with a simple structure.

[0008] The disclosed technology relates to a liquid state sensor attached in the middle of a pipe through which a liquid flows.

[0009] The liquid state sensor comprises a connection section having a main flow path that relays the flow path of the piping, a diversion section having a bypass flow path branched from the main flow path, and a detection section that detects the color of transmitted light that passes through the liquid flowing through the bypass flow path. The cross-sectional area of ​​the bypass flow path is formed to be smaller than the cross-sectional area of ​​the main flow path, and the detection section is mounted on the side of the bypass flow path.

[0010] This liquid state sensor detects liquids that are in flow. Therefore, it is less susceptible to interference from foreign objects, and false detections can be suppressed.

[0011] The diversion section may have a light-transmitting section formed so that light is transmitted around the bypass channel, and the detection section may have a light-receiving section that receives the transmitted light, with the light-receiving section attached to the light-transmitting section.

[0012] This allows for the detection of the color of transmitted light passing through a liquid using a simple structure.

[0013] The diameter of the bypass channel in the light-transmitting portion may be 5 mm or more and 20 mm or less.

[0014] This allows for accurate detection of the color of transmitted light passing through a liquid, with just the right amount of detection performance.

[0015] The flow distribution section and the connection section may be configured to be separable, and the connection section may be replaceable depending on the size of the piping.

[0016] This makes it easy to apply to existing equipment, offering superior convenience.

[0017] A differential pressure generating mechanism may be provided to generate a pressure difference between the upstream branch and the downstream branch of the main flow channel to which the bypass flow channel branches.

[0018] For example, the differential pressure generating mechanism may include a throttling section provided in the portion of the main flow path between the upstream branch and the downstream branch. Alternatively, it may include an extended end of the bypass flow path protruding into the interior of the downstream branch.

[0019] This would facilitate the flow of liquid into the bypass channel.

[0020] The light-transmitting portion may have a block body formed of a light-transmitting material, in which a part of the bypass channel is formed internally, and the block body may be assembled to the connecting portion so that they are integrated.

[0021] This would allow for a more compact liquid state sensor.

[0022] The flow diversion section may further have two specific bolts having hollow shafts, and the light-transmitting section is fastened to the connection section at two locations, the upstream and downstream portions, with the bolts, thereby assembling the light-transmitting section to the connection section and forming the upstream and downstream portions of the bypass flow path with the bolts.

[0023] This allows specific bolts to function as fastening members and piping. Consequently, advantages such as a reduction in the number of parts and miniaturization of liquid state sensors can be obtained.

[0024] The piping is a return pipe that causes the liquid to flow down toward the liquid level in the tank, and a liquid holding mechanism may be provided to stop the liquid in the bypass channel when the flow of the liquid from the return pipe stops.

[0025] This way, even if the liquid flow stops, the liquid state sensor can still detect the liquid's condition.

[0026] The liquid state sensor may also be applied to a liquid state determination device.

[0027] In other words, the liquid state determination device may include the above-described liquid state sensor and a determination unit electrically connected to the detection unit and having comparative information regarding the state of the liquid, wherein the determination unit determines the state of the liquid based on the output value of the detection unit and the comparative information.

[0028] This liquid state determination device can determine the state of a liquid with high accuracy.

[0029] The liquid state sensor may also be applied to a hydraulic unit.

[0030] That is, the hydraulic unit may include an oil tank for storing hydraulic fluid, an oil supply pipe for distributing the hydraulic fluid from the oil tank, an oil return pipe for returning the hydraulic fluid to the oil tank, and the liquid state sensor described above, wherein the liquid state sensor is attached to either the oil supply pipe or the oil return pipe to detect the state of the hydraulic fluid.

[0031] This hydraulic unit can accurately detect the degree of deterioration of the hydraulic fluid.

[0032] This is a schematic diagram of a hydraulic unit to which the disclosed technology is applied. This is a simplified diagram showing the relationship between the hydraulic unit and its related equipment. This is a schematic diagram showing the structure of the first sensor. This is a schematic diagram showing the parts of the block body and the sensor body. This is a block diagram of the information processing device and its related equipment. This is a schematic diagram showing the second sensor. This is a schematic cross-sectional view along the arrow line Y1 in Figure 5. This is a schematic diagram viewed from the direction of arrow Y2 in Figure 6. This is a schematic diagram showing another example of a differential pressure generation mechanism. This is a schematic diagram showing another example of a differential pressure generation mechanism. This is a schematic diagram showing a suitable location for installing a liquid holding mechanism in the first sensor. This is a schematic diagram showing a suitable location for installing a liquid holding mechanism in the second sensor. This is a schematic diagram showing an example of a liquid holding mechanism. This is a schematic diagram showing an example of a liquid holding mechanism. This is a schematic diagram showing an example of a liquid holding mechanism. This is a schematic diagram showing another form of the detection unit.

[0033] The following describes the disclosed technology. However, the following description is for illustrative purposes only. The terms upstream and downstream used in the description correspond to the direction of liquid flow. The direction of liquid flow is indicated by arrow F in the diagram.

[0034] <Hydraulic Unit> Figure 1 shows a hydraulic unit 100 that handles hydraulic fluid as a suitable example for the application of the disclosed technology. Therefore, in this embodiment, the hydraulic fluid corresponds to a "liquid".

[0035] Figure 2 shows a simplified diagram illustrating the relationship between the hydraulic unit 100 and its related equipment. The hydraulic unit 100 circulates and supplies hydraulic fluid to the external hydraulic equipment 200. The external hydraulic equipment 200 can be any equipment that is driven by hydraulics. Examples of external hydraulic equipment 200 include machine tools, heavy machinery, and hydraulic sluice gates.

[0036] The hydraulic unit 100 includes an oil tank 101 (equivalent to a tank) for storing hydraulic fluid, and a frame 102 mounted on top of the oil tank 101. On the frame 102 are a hydraulic pump 103 (see Figure 2), a motor 104 (see Figure 2) for driving the hydraulic pump 103, an oil cooler 105 for cooling the hydraulic fluid discharged from the hydraulic pump 103, a controller 106 for controlling the motor 104, and a cooling fan 107 for air-cooling the motor 104 and the oil cooler 105.

[0037] As shown in Figure 2, an oil supply pipe 110 and an oil return pipe (distribution return pipe 130, described later) are installed between the hydraulic unit 100 and the external hydraulic equipment 200. The oil supply pipe 110 delivers hydraulic fluid from the oil tank 101 to the external hydraulic equipment 200. On the other hand, the oil return pipe returns the hydraulic fluid that has been delivered to the external hydraulic equipment 200 back to the oil tank 101.

[0038] The oil supply piping 110 consists of one suction pipe 111, one discharge pipe 112, and one or more (multiple in the illustration) distribution supply pipes 113. The suction pipe 111 hangs down into the oil tank 101 with its downstream end connected to the suction port of the hydraulic pump 103. The upstream end of the discharge pipe 112 is connected to the discharge port of the hydraulic pump 103. The downstream end of the discharge pipe 112 is connected to the inlet of the distributor 114.

[0039] The external hydraulic equipment 200 typically has multiple hydraulic drive units (e.g., hydraulic cylinders) that require hydraulic pressure. The distributor 114 distributes and supplies hydraulic fluid to each of these hydraulic drive units. The upstream end of the distribution and supply piping 113 is connected to each of the multiple outlets of the distributor 114. The downstream end of each distribution and supply piping 113 is connected to each hydraulic drive unit of the external hydraulic equipment 200.

[0040] The oil return piping consists of one or more (multiple shown in the illustration) distribution oil return pipes 130. The upstream end of each distribution oil return pipe 130 is connected to the hydraulic drive unit of the external hydraulic equipment 200. The downstream end of each distribution oil return pipe 130 hangs down into the oil tank 101. From the hydraulic drive unit of the external hydraulic equipment 200, hydraulic fluid is returned to the oil tank 101 through these distribution oil return pipes 130.

[0041] The oil return pipe further includes a drain pipe 131 of the hydraulic pump 103. The drain pipe 131 is a pipe for returning the surplus hydraulic oil generated by the hydraulic pump 103. The drain pipe 131 is suspended into the oil tank 101 with its upstream end connected to the drain outlet of the hydraulic pump 103.

[0042] The hydraulic oil in the oil tank 101 is always set so that its liquid level is below a predetermined height located below the upper end of the oil tank 101. Therefore, there is always a space (oil upper space) in the upper part of the oil tank 101. The distribution oil return pipe 130 has a downstream end located below the liquid level and always existing in the hydraulic oil (submerged pipe 130a), and a downstream end located above the liquid level and always existing in the oil upper space (above-oil pipe 130b).

[0043] The submerged pipe 130a allows the hydraulic oil to flow out in the stored hydraulic oil. Therefore, it does not cause the liquid level to foam and does not mix air bubbles into the stored hydraulic oil. On the other hand, there is a distribution oil return pipe 130 where oil leakage occurs in the hydraulic drive unit when back pressure is applied. The downstream end of such a distribution oil return pipe 130 needs to be open to the atmosphere. Therefore, such a distribution oil return pipe 130 is an above-oil pipe 130b (corresponding to a return pipe) that allows the hydraulic oil to flow down toward the liquid level in the oil upper space.

[0044] The sizes of these oil supply pipes 110 and distribution oil return pipes 130 vary depending on their applications and specifications. For example, the sizes of the suction pipe 111 and the discharge pipe 112 allow the entire amount of the circulated and supplied hydraulic oil to flow through. Therefore, these sizes are relatively large. In contrast, the sizes of the distribution supply pipe 113 and the distribution oil return pipe 130 allow the distributed amount of hydraulic oil to flow through. Therefore, these sizes are relatively small.

[0045] In each of the distribution supply pipe 113 and the distribution oil return pipe 130, the individual sizes also vary depending on the distribution amount and specifications. Specifically, pipes with sizes ranging from 10A (outer diameter: 17.3 mm, inner diameter: 12.7 mm) to 125A (outer diameter: 139.8 mm, inner diameter: 130.8 mm) are generally used for these distribution supply pipe 113 and distribution oil return pipe 130.

[0046] <Liquid State Sensor, Liquid State Determination Device> The hydraulic oil deteriorates over time due to oxidation and the like. When the deterioration progresses, it becomes necessary to replace the hydraulic oil. As the deterioration progresses, the color of the hydraulic oil changes. Therefore, the degree of deterioration of the hydraulic oil can be determined from the color change. In order to detect the color of the hydraulic oil and determine the degree of deterioration of the hydraulic oil, a liquid state determination device including a liquid state sensor is installed in the hydraulic unit 100.

[0047] In order to detect the color of the hydraulic oil, the liquid state sensor detects the color of the transmitted light that passes through the hydraulic oil. If the hydraulic oil stored in the oil tank 101 is made the detection target of the liquid state sensor, since there is almost no flow of the hydraulic oil, there is a risk of false detection due to the influence of foreign matter.

[0048] Therefore, in the disclosed technology, the liquid state sensor is attached in the middle of the pipe through which the hydraulic oil flows. The flow of the hydraulic oil can effectively prevent false detection due to the influence of foreign matter.

[0049] As a pipe suitable for attaching the liquid state sensor instead of the oil tank 101, the suction pipe 111, the discharge pipe 112, and the distribution return oil pipe 130 arranged around the oil tank 101 can be considered.

[0050] However, the suction pipe 111 and the discharge pipe 112 have large pressure fluctuations in relation to the hydraulic pump 103. Also, there may be limited places where they can be attached. Therefore, in this embodiment, the liquid state sensor is attached to the distribution return oil pipe 130.

[0051] There are a plurality of distribution return oil pipes 130, and each has a different size. Depending on the structure of the hydraulic unit 100, if the liquid state sensor can be attached to any of these distribution return oil pipes 130, it can be easily applied to the existing hydraulic unit 100.

[0052] For example, the lubricating oil deterioration sensor of Patent Document 1 described above can also be attached to distribution return oil pipes 130 of different sizes. However, because the structure is complex and delicate, it is prone to failure and difficult to repair. It is also necessary to drill holes in the distribution return oil pipe 130. This can cause oil leakage. It is an additional process, and the existing hydraulic unit 100 cannot be used as it is.

[0053] In contrast, detection can be achieved with a relatively simple structure by shining light across the distribution and return oil piping 130 and receiving the light from the side. Furthermore, the existing hydraulic unit 100 can be used as is. The structure is simple and easy to repair.

[0054] However, the distribution and return oil piping 130 is large in size. A high-output light-emitting device is required to obtain the necessary amount of light for detection. As a result, the cost of materials and running costs will be high.

[0055] Therefore, the disclosed technology features a liquid state sensor structure designed to be installed in the middle of a pipe at a low cost. Specifically, a small bypass channel 21 is provided in the distribution and return oil pipe 130, and the color of the transmitted light crossing the bypass channel 21 is detected.

[0056] Specifically, in the first embodiment described later, the liquid state sensor 1 comprises "connection parts" 31, 32 having a main flow path 20 that relays the flow path of the distribution return oil piping 130, "flow division parts" 33a to 33c, 34, 11 having a bypass flow path 21 branched from the main flow path 20, and a "detection part" 13 that detects the color of transmitted light passing through the hydraulic oil flowing through the bypass flow path 21. The flow path cross-section of the bypass flow path 21 is formed to be smaller than the flow path cross-section of the main flow path 20, and the detection part 13 is attached to the side of the bypass flow path 21.

[0057] By configuring the liquid state sensor 1(2) in this way, the hydraulic fluid flows through the bypass channel 21, thus preventing false detections due to foreign matter. Since it detects the hydraulic fluid flowing through the bypass channel 21, which has a small channel cross-section, the detection unit can be configured with appropriate performance according to its detection accuracy. Since detection is performed from the side of the bypass channel 21, the components related to detection can be installed on the outside of the bypass channel 21. Therefore, installation and replacement are easy, and the structure can be made relatively simple.

[0058] The supply of hydraulic fluid is intermittent. The hydraulic fluid flows through the main passage 20 intermittently. However, if there is a difference in the cross-sectional area of ​​the main passage 20 and the bypass passage 21 as described above, when the flow of hydraulic fluid in the main passage 20 suddenly stops, the hydraulic fluid in the bypass passage 21 will flow backward. This also helps to prevent foreign matter from entering the bypass passage 21. The same applies to the second embodiment described later.

[0059] (First Embodiment) Figure 3 shows an example of an assembly-type liquid state sensor (hereinafter also referred to as the first sensor 1). The first sensor 1 is composed of a sensor member 10 and an existing piping member 30.

[0060] Specifically, the piping component 30 includes a pair of T-pipes 31, 31, a short pipe 32, first to third conduit members 33a to 33c, a hose 34, etc. These are integrated by connecting the pair of T-pipes 31, 31 with the short pipe 32.

[0061] A main flow path 20 is formed inside the integrated pair of T-pipes 31, 31 and short pipe 32, which relays the flow path of the distribution and return oil piping 130. The pair of T-pipes 31, 31 and short pipe 32 constitute a "connection section". Therefore, their size (size of the flow path cross-section or diameter of the flow path) is the same as that of the distribution and return oil piping 130.

[0062] Flow channels constituting the bypass channel 21 are formed inside the first to third pipeline members 33a to 33c and the hose 34. The first to third pipeline members 33a to 33c and the hose 34 constitute a "flow diversion section". Therefore, the size of these flow channels is smaller than that of the distribution and return oil piping 130.

[0063] The "connection part" of the first sensor 1 is attached using the connection part of the distribution and return oil piping 130 to be installed. The distribution and return oil piping 130 usually has a connection part that connects two pipes. The "connection part" is interposed between them. Therefore, it can be easily applied to existing hydraulic units 100. By selecting T-pipes 31 and short pipes 32, it can be easily adapted to distribution and return oil piping 130 of different sizes.

[0064] The first pipe member 33a and the second pipe member 33b are screwed to each of the lateral joints of the T-pipe 31. In other words, the "connection section" and the "flow distribution section" are configured to be separable. Therefore, by selecting and interposing joints, the first pipe member 33a and the second pipe member 33b can be screwed to each of the joints of different sizes. The existing distribution and return oil piping 130 can be used as is.

[0065] The first conduit member 33a, located upstream, is connected to the third conduit member 33c via a hose 34. By bending the hose 34 into an L-shape, the end of the first conduit member 33a and the end of the third conduit member 33c are positioned to face each other. The sensor member 10 is then attached to the first conduit member 33a and the third conduit member 33c, interposed between these opposing ends.

[0066] The sensor component 10 of this first sensor 1 consists of a block body 11, a sensor case 12, a sensor body 13 (corresponding to the "detection unit"), a microcontroller 14 (corresponding to the "determination unit"), and the like. The block body 11, the sensor body 13, and the microcontroller 14 are housed in the sensor case 12.

[0067] Figure 4A illustrates the parts of the block body 11 and the sensor body 13. The block body 11 is formed in a rectangular prism shape from a light-transmitting material (for example, transparent resin). Inside the block body 11, a bypass relay channel 21a is formed, extending along the center line of the block body 11.

[0068] The bypass relay channel 21a penetrates the block body 11. The block body 11 is connected to the first and third pipeline members 33a and 33c by screw connections. The bypass relay channel 21a communicates with each of the bypass channels 21 of the first and third pipeline members 33a and 33c.

[0069] The bypass relay channel 21a constitutes a part of the bypass channel 21. Therefore, the block body 11 constitutes a part of the "flow diversion section". In addition, the area around the bypass relay channel 21a is transparent to light. The "light-transmitting section" is composed of the block body 11.

[0070] The sensor body 13 is bolted to the side of the block body 11. The sensor body 13 has a light-emitting part 13a and a light-receiving part 13b on the mounting surface to the block body 11. A reflective material 15 that reflects light is attached to the surface of the block body 11 opposite to the sensor body 13.

[0071] The light-emitting unit 13a emits detection light that passes through the bypass relay channel 21a and is directed toward the reflector 15, as shown by the arrow line A1 in Figure 4A. In this embodiment, the light-emitting unit 13a is a white light-emitting LED. The light-emitting unit 13a emits white detection light. The light-emitting unit 13a may also emit laser light.

[0072] Furthermore, to facilitate detection of the hydraulic fluid color, the diameter of the bypass relay channel 21a is preferably 5 mm to 20 mm. If it is less than 5 mm, the hydraulic fluid flow will be insufficient, and there is a risk of clogging by foreign matter. If it exceeds 20 mm, the size will be excessive for the detection accuracy, resulting in unnecessary costs.

[0073] The light-receiving unit 13b receives transmitted light that has passed through the hydraulic fluid flowing through the bypass relay channel 21a and been reflected by the reflector 15, as shown by the arrow line A2 in Figure 4A. This sensor body 13 is of the reflective type.

[0074] The sensor body 13 may be of the transmissive type. That is, the light-emitting unit 13a and the light-receiving unit 13b are arranged opposite each other via the block body 11. In other words, the reflective material 15 is replaced by the light-receiving unit 13b. Light is then emitted from the light-emitting unit 13a towards the light-receiving unit 13b. The transmitted light that has passed through the hydraulic fluid flowing through the bypass relay channel 21a is received directly by the light-receiving unit 13b.

[0075] The light-receiving unit 13b, although not shown in the figure, includes a light-receiving element that converts the amount of light into an electrical signal, an amplification circuit that amplifies the electrical signal output by the light-receiving element, and an A / D conversion circuit that converts the analog electrical signal amplified by the amplification circuit into a digital electrical signal. The light-receiving element detects the electrical signal converted from the received visible light, separating it into red, green, and blue.

[0076] In other words, the light-receiving element is an RGB color sensor. The light-receiving unit 13b outputs detection values ​​R, G, and B for the red, green, and blue colors contained in the transmitted light. The light-receiving unit 13b is connected to the microcontroller 14 by electrical wiring. These detection values ​​are output as electrical signals from the light-receiving unit 13b to the microcontroller 14.

[0077] Figure 4B shows a block diagram of the microcontroller 14 and its related equipment. The microcontroller 14 has hardware such as a processor 14a, memory 14b, and interface 14c, and software such as processing programs. The microcontroller 14 is connected to the controller 106 of the hydraulic unit 100 by a wire. The microcontroller 14 transmits electrical signals of detected values ​​to the controller 106 and receives control signals from the controller 106.

[0078] The microcontroller 14 is also wirelessly connected to an external information device 201. The microcontroller 14 transmits an electrical signal of the detected value to the external information device 201 and receives a control signal from the external information device 201.

[0079] The microcontroller 14 has comparison information 14d regarding the state of the hydraulic fluid. Based on the detected electrical signal (output value) and the comparison information 14d, the microcontroller 14 determines the state of the hydraulic fluid, that is, the degree of deterioration of the hydraulic fluid.

[0080] Comparative information 14d includes data on the ASTM color of the hydraulic fluid. Specifically, comparative information 14d includes data summarizing the correspondence between the degree of hydraulic fluid degradation and the hue (ASTM color) of the hydraulic fluid. The ASTM color is an indicator of the degree of hydraulic fluid degradation. The higher the ASTM color value, the more advanced the degradation of the hydraulic fluid.

[0081] The microcontroller 14 compares the detected electrical signal with the comparison information 14d. By doing so, the microcontroller 14 can determine the degree of deterioration of the hydraulic fluid. The microcontroller 14 outputs the determination result as an electrical signal to the controller 106 and / or external information device 201. The first sensor 1 and the microcontroller 14 constitute a "liquid state determination device". In Figure 4B, the liquid state determination device is indicated by reference numeral 5.

[0082] (Second form) Figure 5 shows an example of an integrated liquid state sensor (hereinafter also referred to as second sensor 2) as another form of the liquid state sensor. Figure 6 shows a schematic cross-sectional view along the arrow line Y1 in Figure 5. Figure 7 shows a schematic view from the direction of arrow Y2 in Figure 6.

[0083] The basic configuration of the second sensor 2 is the same as that of the first sensor 1. Therefore, we will describe the configuration that differs from that of the first sensor 1. For configurations that are the same as those of the first sensor 1, we will use the same reference numerals and simplify or omit their explanation.

[0084] The second sensor 2 is composed of a sensor member 10 and a piping block 50 (corresponding to the "connection part"). As shown in Figure 5, the piping block 50 is available in multiple different sizes (three are shown as examples in Figure 5) according to the standard size of the distribution return piping 130. The piping block 50 to be used is selected according to the distribution return piping 130 to which it is to be installed.

[0085] The piping block 50 has a rectangular prism shape. Inside the piping block 50, a main flow path 20 is formed that extends and penetrates along its centerline. Threaded portions 50a with female threads are provided at both ends of the main flow path 20. As shown in Figure 6, the piping block 50 is installed in the middle of the distribution and return oil piping 130, interposed at the connection point of the distribution and return oil piping 130 via these threaded portions 50a.

[0086] The sensor component 10 of this second sensor 2 consists of a block body 11, two specific bolts (specific bolts) 52, a sensor case 12, a sensor body 13, a microcontroller 14, and the like.

[0087] Inside the block body 11, a bypass relay channel 21a is formed, extending along the centerline of the block body 11. The bypass relay channel 21a of the second sensor 2 does not penetrate the block body 11. Both ends of the bypass relay channel 21a are located inside the block body 11 and are closed. At two locations on both ends of the block body 11 (the upstream side and the downstream side), a pair of lateral insertion holes 53, 53 are formed, extending perpendicular to the centerline of the block body 11.

[0088] These lateral insertion holes 53 penetrate both ends of the bypass relay channel 21a and also penetrate a pair of opposing first sides of the block body 11. As shown in Figure 7, a sensor body 13 and a reflector 15 are attached to each of the pair of opposing second sides of the block body 11.

[0089] A specific bolt 52 is inserted through each of the lateral insertion holes 53. The specific bolt 52 has a shaft portion 52a with a male thread formed at its tip, and a large-diameter hexagonal head 52b connected to the end of the shaft portion 52a. Inside the shaft portion 52a, an elongated hole 52c is formed, extending along the center line of the shaft portion 52a. In other words, the shaft portion 52a is hollow.

[0090] One end of the elongated hole 52c opens at the tip of the shaft portion 52a. The other end of the elongated hole 52c is located inside the shaft portion 52a and is closed. A lateral through hole 52d is formed on the other end side of the elongated hole 52c, extending perpendicularly to the elongated hole 52c. When a specific bolt 52 is inserted to its limit into the lateral insertion hole 53, the lateral through hole 52d communicates with the bypass relay channel 21a.

[0091] Mounting holes 12a are formed on the bottom surface of the sensor case 12 at two locations corresponding to a pair of lateral insertion holes 53, 53. Two specific bolts 52 inserted through the block body 11 are attached to these mounting holes 12a via inner packing 54. As a result, as shown in Figure 5, the tips of the specific bolts 52 protrude from the bottom surface of the sensor case 12.

[0092] A pair of lateral screw holes 50b, 50b are formed on the side surface of the piping block 50. These lateral screw holes 50b are positioned separately along the main flow path 20, on the upstream and downstream sides. The lateral screw holes 50b are in communication with the main flow path 20.

[0093] The tips of each specific bolt 52 protruding from the bottom surface of the sensor case 12 are screwed (fastened) into each lateral screw hole 50b via the outer packing 55. As a result, the block body 11, while housed in the sensor case 12, is assembled and integrated with the piping block 50.

[0094] Therefore, the second sensor 2 is smaller in size and more compact than the first sensor 1. Furthermore, the size and arrangement of the lateral screw holes 50b are standardized across all sizes of piping blocks 50. Consequently, the sensor member 10 of the second sensor 2 can be shared among multiple piping blocks 50. The piping blocks 50 can be easily replaced.

[0095] The main channel 20 is in communication with the bypass relay channel 21a via the elongated holes 52c and the transverse through-holes 52d located on the upstream and downstream sides. This forms the bypass channel 21 branched from the main channel 20. The portion of the main channel 20 where the transverse screw hole 50b on the upstream side is open constitutes the "upstream branch section," and the portion of the main channel 20 where the transverse screw hole 50b on the downstream side is open constitutes the "downstream branch section." In Figure 6, the upstream branch section 22 is indicated by reference numeral 22, and the downstream branch section 23 is indicated by reference numeral 23.

[0096] By fastening each specific bolt 52 to the piping block 50, the elongated holes 52c and lateral through holes 52d of each specific bolt 52 constitute a part of the bypass channel 21 (the upstream and downstream portions of the bypass channel 21). In other words, the specific bolts 52 function as fastening members and piping. The specific bolts 52 offer advantages such as a reduction in the number of parts and miniaturization.

[0097] As hydraulic fluid flows through the main channel 20, it also flows through the bypass channel 21, as shown by the dashed arrow Fb in Figure 6.

[0098] Furthermore, the piping block 50 of the second sensor 2 is equipped with a mechanism to promote the flow of hydraulic fluid to the bypass passage 21. Specifically, a differential pressure generating mechanism 60 is provided in the piping block 50. The differential pressure generating mechanism 60 generates a pressure difference between the upstream branch 22 and the downstream branch 23 of the main passage 20.

[0099] Figure 6 shows a throttling section 61 as an example of the differential pressure generation mechanism 60. The throttling section 61 is provided in the portion of the main flow path 20 between the upstream branch section 22 and the downstream branch section 23. The throttling section 61 is constructed by making the size of the flow path cross-section smaller than the flow path cross-section of the main flow path 20.

[0100] The hydraulic fluid flowing through the main channel 20 is obstructed at the throttling section 61. This creates a pressure difference between the upstream branch section 22 and the downstream branch section 23, thereby promoting the flow of hydraulic fluid from the upstream branch section 22 to the bypass channel 21.

[0101] The throttling section 61 is not limited to simply narrowing a portion of the main flow path 20. A protruding inward projection may be provided on the inner surface of the main flow path 20. A wall-like rib may also be provided. In other words, the throttling section 61 only needs to have a flow path cross-section smaller than the main flow path 20, regardless of the size in the flow direction. For example, in the case of the first sensor 1, a smaller pipe may be interposed. This allows the throttling section 61 to be realized.

[0102] Figure 8A shows another example of the differential pressure generation mechanism 60. This differential pressure generation mechanism 60 is composed of an extended end 62 of a bypass channel 21 that protrudes into the interior of the downstream branch section 23.

[0103] Specifically, the shaft portion 52a of the downstream specific bolt 52 is longer than the shaft portion 52a of the upstream specific bolt 52. The tip of the shaft portion 52a of the upstream specific bolt 52 is located near the wall surface of the main flow channel 20 or inside the lateral screw hole 50b. In contrast, the shaft portion 52a of the downstream specific bolt 52 protrudes from the wall surface of the main flow channel 20 (extended end portion 62). As a result, the tip of the shaft portion 52a of the downstream specific bolt 52 is located inside the main flow channel 20.

[0104] The hydraulic fluid flowing through the main channel 20 is obstructed by the extended end 62. This disrupts the flow of hydraulic fluid at the downstream branch 23, creating a pressure difference between the upstream branch 22 and the downstream branch 23, thereby promoting the flow of hydraulic fluid from the upstream branch 22 to the bypass channel 21.

[0105] Figure 8B shows another example of the differential pressure generation mechanism 60. This differential pressure generation mechanism 60 is constructed by making the cross-sectional area of ​​the bypass flow path 21 larger on the downstream side than on the upstream side.

[0106] Specifically, the downstream elongated hole 52c is formed with a larger diameter than the upstream elongated hole 52c. The downstream transverse through hole 52d is formed with a larger diameter than the upstream transverse through hole 52d.

[0107] As a result, the hydraulic fluid flows more easily downstream of the bypass channel 21 than upstream. The hydraulic fluid flowing through the main channel 20 exerts an attractive force on the bypass channel 21 toward the main channel 20. Due to the difference in flow ease, a difference in attractive force is created between the upstream and downstream sides of the bypass channel 21, resulting in a pressure difference between the upstream branch 22 and the downstream branch 23. This promotes the flow of hydraulic fluid from the upstream branch 22 to the bypass channel 21.

[0108] (Considerations when installing on piping above the oil level) As described above, within the distribution and return oil piping 130, there is a piping above the oil level 130b whose downstream end is in the space above the oil level, allowing the hydraulic fluid to flow down toward the liquid level. When the liquid state sensor is installed on this piping above the oil level 130b, there is a risk that the liquid state sensor will not function when the hydraulic unit 100 is stopped.

[0109] In other words, when the hydraulic unit 100 is stopped, the hydraulic fluid is not circulated and supplied. Consequently, the flow of hydraulic fluid in the distribution and return oil pipe 130 also ceases. In the case of the above-oil-level pipe 130b, since its downstream end is open to the atmosphere, the hydraulic fluid inside flows out due to gravity. Consequently, hydraulic fluid may flow out of the bypass channel 21, and the bypass channel 21 may become empty.

[0110] If the bypass channel 21 becomes empty, the color of the hydraulic fluid cannot be detected. In other words, the liquid state sensor will not function. The hydraulic fluid deteriorates regardless of whether the hydraulic unit 100 is used or not. Therefore, in hydraulic units 100 that are used infrequently, deterioration of the hydraulic fluid may not be detected.

[0111] Therefore, when attaching the liquid state sensor to the above-oil-level piping 130b, it is preferable to provide the liquid state sensor with a mechanism (liquid holding mechanism 70) that stops the hydraulic fluid from flowing down the above-oil-level piping 130b into the bypass passage 21 when the hydraulic fluid stops flowing down.

[0112] Figures 9A and 9B show, with dashed circles C, locations in the first sensor 1 and second sensor 2 described above where the liquid retention mechanism 70 is suitable for installation. The liquid retention mechanism 70 is preferably installed at the downstream end of the bypass channel 21. This prevents the outflow of hydraulic fluid from the bypass channel 21 even if the inflow of hydraulic fluid into the bypass channel 21 ceases.

[0113] For the first sensor 1, the liquid holding mechanism 70 can be installed by performing additional machining around the downstream end of the block body 11 or by attaching a separate part. For the second sensor 2, the liquid holding mechanism 70 can be installed by performing additional machining around the downstream branch section 23. Figures 10A to 10C show specific examples of the liquid holding mechanism 70.

[0114] Figure 10A shows that the fluid retention mechanism 70 is composed of a pivotable valve body 71. The valve body 71 is installed between the main passage 20 and the downstream end of the bypass passage 21. When the hydraulic unit 100 stops, that is, when the flow of hydraulic fluid from the above-oil-level piping 130b stops, the valve body 71 closes, blocking the passage between the main passage 20 and the bypass passage 21.

[0115] Figure 10B shows that the fluid retention mechanism 70 is composed of a check valve 72. When the hydraulic unit 100 is operating, the check valve 72 opens due to the pressure of the hydraulic fluid flowing through the bypass passage 21. When the hydraulic unit 100 stops, the check valve 72 closes, blocking the connection between the main passage 20 and the bypass passage 21.

[0116] Figure 10C shows that the liquid holding mechanism 70 is composed of a bent channel 73. The bent channel 73 is bent in an inverted U shape toward the upper vertical direction. The upper part of the bent channel 73 is configured to be located above the bypass relay channel 21a.

[0117] As a result, when the hydraulic unit 100 stops, the hydraulic fluid in the bypass relay channel 21a is blocked by the bent channel 73, as shown in Figure 10C. This retains the hydraulic fluid in the bypass relay channel 21a.

[0118] <Another form of the detection unit> In the above-described embodiment, the state of the hydraulic fluid was detected using a sensor body 13 having a light-emitting unit 13a and a light-receiving unit 13b. Alternatively, the state of the hydraulic fluid may be detected using a sensor body 13 having only a light-receiving unit 13b.

[0119] Figure 11 shows a specific example. In this embodiment, the sensor body 13 has only a light-receiving section 13b. The surface of the sensor body 13 facing the block body 11 is exposed to the outside (light-collecting surface 80). This allows external light rays (external light rays L), consisting of natural light or artificial light (such as fluorescent light), to enter the block body 11 through the light-collecting surface 80.

[0120] Then, the light receiving unit 13b receives external light rays that have passed through the hydraulic fluid flowing through the bypass relay channel 21a, and the light receiving unit 13b detects the color of the transmitted light. With this detection unit, the light emitting unit 13a can be omitted, so a liquid state sensor can be realized at a lower cost.

[0121] Furthermore, the disclosed technology is not limited to the embodiments described above. The disclosed technology also includes configurations other than those described in the embodiments.

[0122] For example, the liquid is not limited to oil. Any fluid that can change color is acceptable. The liquid state sensor is preferably installed at a pipe connection point, but it is not limited to that. If there is a branch point in the pipe itself, that can also be used.

[0123] The details described individually for the first sensor 1 and the second sensor 2 are applicable to each other. For example, the first sensor 1 may be provided with the differential pressure generating mechanism 60 described for the second sensor 2.

[0124] 1 First sensor (liquid state sensor) 2 Second sensor (liquid state sensor) 5 Liquid state determination device 10 Sensor component 11 Block body (light transmitting part) 12 Sensor case 12a Mounting hole 13 Sensor body (detection part) 13a Light emitting part 13b Light receiving part 14 Microcontroller (determination part) 14a Processor 14b Memory 14c Interface 14d Comparison information 15 Reflective material 20 Main flow path 21 Bypass flow path 21a Bypass relay flow path 22 Upstream branch 23 Downstream branch 30 Piping component 31 T-pipe (connection part) 32 Short pipe (connection part) 33a-33c Pipe component (flow diversion part) 34 Hose (flow diversion part) 50 Piping block (connection part) 50a Threaded part 50b Side threaded hole 52 Specific bolt 52a Shaft section 52b Head section 52c Slotted hole (bypass passage) 52d Lateral through hole (bypass passage) 53 Lateral insertion hole 54 Inner packing 55 Outer packing 60 Differential pressure generation mechanism 61 Throttle section 62 Extended end section 70 Liquid retention mechanism 71 Valve body 72 Check valve 73 Bent passage 80 Light-gathering surface 100 Hydraulic unit 101 Oil tank 102 Stand 103 Hydraulic pump 104 Motor 105 Oil cooler 106 Controller 107 Cooling fan 110 Oil supply piping 111 Suction piping 112 Discharge piping 113 Distribution supply piping 114 Distributor 130 Distribution return piping (return piping) 130a Piping below oil level 130b Piping above oil level (return piping) 131 Drain piping 200 External hydraulic equipment 201 External information equipment

Claims

1. A liquid state sensor (1, 2) installed in the middle of a pipe (130) through which a liquid flows, comprising: a connection section (31, 32) having a main flow path (20) that relays the flow path of the pipe (130); a diversion section (33a to 33c, 34, 11) having a bypass flow path (21) branched off from the main flow path (20); and a detection section (13) that detects the color of transmitted light that has passed through the liquid flowing through the bypass flow path (21), wherein the cross-sectional area of ​​the bypass flow path (21) is formed to be smaller than the cross-sectional area of ​​the main flow path (20), and the detection section (13) is installed on the side of the bypass flow path (21).

2. A liquid state sensor according to claim 1, wherein the flow division section (33a to 33c, 34, 11) has a light-transmitting section (11) formed so that light is transmitted around the bypass flow path (21), the detection section (13) has a light-receiving section (13b) that receives the transmitted light, and the light-receiving section (13b) is attached to the light-transmitting section (11).

3. A liquid state sensor according to claim 2, wherein the diameter of the bypass channel (21) in the light-transmitting portion (11) is 5 mm or more and 20 mm or less.

4. A liquid state sensor according to any one of claims 1 to 3, wherein the flow distribution section (33a to 33c, 34, 11) and the connection section (31, 32) are configured to be separable, and the connection section (31, 32) can be replaced according to the size of the piping (130).

5. A liquid state sensor according to any one of claims 1 to 4, wherein a differential pressure generating mechanism (60) is provided that generates a pressure difference between the upstream branching portion (22) and the downstream branching portion (23) of the main flow path (20) to which the bypass flow path (21) branches.

6. A liquid state sensor according to claim 5, wherein the differential pressure generating mechanism (60) includes a throttling portion (61) provided in the portion between the upstream branch portion (22) and the downstream branch portion (23) of the main flow path (20).

7. A liquid state sensor according to claim 5 or 6, wherein the differential pressure generating mechanism (60) is configured to include an extended end (62) of the bypass channel (21) that protrudes into the interior of the downstream branch (23).

8. A liquid state sensor according to claim 2 or 3, wherein the light-transmitting portion (11) has a block body formed of a light-transmitting material and having a part of the bypass channel (21) formed inside, and the block body is assembled to the connecting portions (31, 32) and these are integrated.

9. A liquid state sensor according to claim 8, wherein the flow division section (33a to 33c, 34, 11) further has two specific bolts (52) having hollow shafts, and the light-transmitting section (11) is assembled to the connection section (31, 32) by fastening the upstream and downstream portions of the light-transmitting section (11) to the connection section (31, 32) with the bolts (52), and the upstream and downstream portions of the bypass flow path (21) are formed by the bolts (52).

10. A liquid state sensor according to any one of claims 1 to 9, wherein the piping (130) is a return piping (130b) that causes the liquid to flow down toward the liquid level in the tank (101), and a liquid holding mechanism (70) is provided to stop the liquid from flowing down from the return piping (130b) into the bypass passage (21).

11. A liquid state determination device (5), comprising: a liquid state sensor (1, 2) described in any one of claims 1 to 10; and a determination unit (14) electrically connected to the detection unit (13) and having comparative information (14d) relating to the state of the liquid, wherein the determination unit (14) determines the state of the liquid based on the output value of the detection unit (13) and the comparative information (14d).

12. A hydraulic unit (100) comprising: an oil tank (101) for storing hydraulic fluid; an oil supply pipe (110) for supplying the hydraulic fluid from the oil tank (101); an oil return pipe (130) for returning the hydraulic fluid to the oil tank (101); and a liquid state sensor (1, 2) as described in any one of claims 1 to 10, wherein the liquid state sensor (1, 2) is attached to either the oil supply pipe (110) or the oil return pipe (130) to detect the state of the hydraulic fluid.

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