JP2010078328A - Optical sensor device - Google Patents

Abstract

【Task】
When an optical sensor is used in an elevator environment with a lot of dust and oil splashes, contamination of the optical window, lens, mirror, etc. is prevented by a simple method.
[Solution]
A lens barrel 0207 having an opening in contact with an external fluid at one end and an optical window 0206 at the other end, and means for generating thermal convection with respect to the lens barrel.
[Selection] Figure 2

Description

  The present invention relates to an optical sensor-related device, and is particularly suitable for an apparatus that detects a position and speed using an optical sensor in a dirty environment such as an elevator hoistway.

  Conventionally, an absolute position in a hoistway of an elevator car has been detected by using pulses from a rotary encoder connected to a speed governor or a motor sheave. Further, in order to use an optical sensor in a dirty environment, as shown in Patent Documents 1 to 3, a method of pumping clean air prepared outside has been used.

JP-A-6-229819 Japanese Patent Laid-Open No. 8-15583 JP 2005-181090 A

  In absolute position detection using a conventional rotary encoder, the carriage and the rotary encoder are indirectly connected via a rope. It could not be obtained with a small delay time. Furthermore, many problems to be considered remain, such as interference (hook) and cutting with the structures in the hoistway of the rope. This tendency becomes more prominent as the head increases.

In the field of distance measurement, a method using optical detection means such as a laser is generally performed.
If the distance from the car to the upper or lower end of the hoistway can be measured, the absolute position of the car can be measured directly without the intervention of a rope. However, the inside of the elevator hoistway is in an environment in which dirt is likely to be generated due to splashes of oils and fats for lubrication and dust brought in from outside the hoistway. Therefore, the application of the optical sensor requires measures against the above-mentioned contamination.

  In what is shown in Patent Documents 1 to 3, in order to pump clean air prepared externally, in order to ensure clean compressed air, it is necessary to newly provide pumps having movable parts. Increased and decreased maintainability.

  An object of the present invention is to solve the above-described problems of the prior art and prevent functional deterioration due to contamination of an optical sensor. In particular, when an optical sensor is used in an elevator environment with a lot of dust or oil splashes, it is to prevent contamination of an optical window, a lens, a mirror, or the like by a simple method.

  In order to achieve the above object, the present invention has an opening at the end in the direction of gravitational acceleration, an optical window at the end opposite to the direction of gravitational acceleration, and is airtight except for the opening in the direction of gravitational acceleration. And an optical sensor device having an optical sensor device having an optical sensor at a position facing the lower opening of the lens barrel through the optical window from the outside of the lens barrel. And means for generating thermal convection in the fluid in the lens barrel.

  An optical sensor device having a lens barrel having an opening at an end in the direction of gravitational acceleration, in which the fluid in the lens barrel has a flow, and in the vicinity of a location where the flow direction changes, the lens barrel There are locations where the amount of accumulated dust transported by the fluid in the interior is relatively large and small, and optical windows are arranged at locations where the amount of accumulated dust is small.

  According to the present invention, heat convection can be formed in the fluid (air) in the lens barrel by the heating means or the cooling means, or the streamlines caused by the convection can be in a direction in which dirt on the optical window does not adhere. It is possible to prevent functional deterioration due to contamination of the optical sensor.

  FIG. 1 shows an elevator apparatus according to an embodiment of the present invention. A car 0105 and a counterweight 0107 are connected to each other by a main rope 0106, and the main rope 0106 is wound around a hoisting machine 0108. The hoisting machine 0108 drives the main rope 0106 according to a command from the control device 0111. As a result, the car 0105 (hereinafter sometimes simply referred to as “car”) and the counterweight 0107 move in the hoistway. A car-side controller 0201 is mounted on the car, and at least an optical sensor unit 0203 is connected to the car-side controller 0201. The car-side control device 0201 performs determination processing using the measurement value from the optical sensor unit 0203 and other measurement values from the sensor 0204 as necessary, and transmits the determination result to the control device 0111 or as necessary. And / or actuate a car-mounted safety device including the emergency stop device 0114. Measurement values from sensors installed in the car such as 0203 and 0204 may be transmitted to the control device 0111 via the car-side control device 0201 or directly.

  An example of an application that requires an accurate measurement of the absolute position of the car is an end-stage reduction gear (ETSD). By applying this function, the maximum speed in the vicinity of the final floor of the hoistway can be reduced, and various advantages such as shortening of pits and overhead lengths and downsizing of shock absorbers can be obtained. FIG. 16 shows an example of the speed limit threshold when the terminal floor reduction gear is applied. The horizontal axis in the figure is the height from the reference position in the hoistway. For example, the pit floor or the lower final limit switch may be used as a reference. The vertical axis represents the car speed. 0301 is a rated speed, which is the speed at which the car runs normally. 0302 is a speed limit, and when this speed is exceeded, it is necessary to perform a braking operation. In the drawing, 0302 is omitted as one, but usually there are at least two threshold values, a threshold value that serves as a trigger for braking via the main rope and a threshold value that serves as a trigger for the emergency stop operation. Reference numerals 0303 and 0304 denote terminal floor reduction gear operating areas. In the figure, the threshold curves near the top floor and the bottom floor are symmetric, but they may be asymmetric. When the terminal floor reduction gear is used, this function is realized by at least one of the control device 0111 or the car-side control device 0201.

  FIG. 2 shows a configuration example of the optical sensor unit 0203. The optical sensor 0205 faces the fluid 0209 in the lens barrel 0207 through an optical window 0206 made of a lens, a prism, or a transparent material. The heating unit 0208 heats the fluid 0209 in the lens barrel. The cooling unit 0212 cools the fluid 0209 in the lens barrel.

  Here, it is assumed that the lens barrel 0207 faces the opening in the gravitational acceleration direction 0211. Hereinafter, the gravitational acceleration direction is expressed as “down” and the same direction and the opposite direction as “up”. In the lens barrel 0207, the opening through which fluid can enter and exit is only the lower end. The flow path separation wall 0216 assists the formation of thermal convection by separating the flow path of the upward flow and the downward flow. In this embodiment, the flow path separation wall 0216 is used as an installation location of the heating means 0208 and the cooling means 0212. However, the combined use of the flow path separation function and the heating / cooling installation function is not essential.

  FIG. 6 shows an example of the installation location of the heating means and the cooling means. FIGS. 9A to 9D are diagrams in which portions of the optical sensor unit 0203 are extracted. FIG. 5A shows an example in which the heating means 0208 is installed outside the lens barrel 0207. Compared with the heating means installation location shown in FIG. 2 above, the installation location has a larger surface area, so the amount of heat input to the fluid in the lens barrel increases and more efficient heat convection can be generated. . Further, as shown in FIG. 6B, it may be used in combination with the installation of the heating means on the flow path separation wall 0216. Similarly, when the flow path shapes are different, the heating means is provided on the wall surface in contact with the rising heat convection, and the cooling means is provided on the wall surface in contact with the falling heat convection. FIGS. 6C and 6D are examples in the case where the flow path shape is not a concentric cylinder. In any case, by providing an isolation distance between the optical axis where the optical target 0219 is desired from the optical window 0206 and the heating / cooling means position, it is possible to reduce the influence of the heat.

  FIG. 7 shows an example of waste heat means. Whereas the heating means can be installed on an independent wall surface alone, when the cooling means using a Peltier element or the like is installed on an independent wall surface, a means for treating waste heat is required. In cases where the heating means is disposed on the surface adjacent to the cooling means as shown in FIG. 2 and FIGS. 6B and 6D, in many cases, the waste heat of the Peltier element can also serve as the heating means. When waste heat cannot be performed on the adjacent surfaces, waste heat is performed outside the lens barrel 0207 using the heat transfer means 0256 and the heat dissipation means 0257 as shown in FIGS. 7 (a) and 7 (b).

  FIG. 8 shows an example of the waste heat diversion. When a Peltier element is used as the cooling / heating means, the amount of heat generated in the element reaches several times the amount of heat absorption. Therefore, only heat radiation from the surface adjacent to the cooling surface may cause an adverse effect due to an imbalance in the heat balance in the lens barrel, such as the wall surface temperature exceeding a desirable temperature range. Then, the heat which generate | occur | produces at the time of cooling can be shared by the some heating means installation location 0208-1, 0208-2 and the thermal radiation means 0257, and can prevent a local temperature rise.

  FIG. 3 shows an example of use of a deflector (baffle plate). The present embodiment is an example in which a desired thermal convection is maintained in the lens barrel even when the moving body in which the lens barrel is installed has a high speed. Here, the desired direction of heat convection is assumed to be a direction rising at the periphery of the lens barrel and descending at the center.

  In FIG. 3A, when the moving direction of the lens barrel with respect to the surrounding fluid is 0250, most of the region in the opening of the lens barrel is in a state higher than the ambient pressure (hereinafter referred to as positive pressure). In the figure, the positive pressure region at the lens barrel opening is indicated by H. Here, as shown in FIG. 7B, when the moving direction of the lens barrel is 0251, the atmospheric pressure is low at the outer periphery of the lens barrel opening due to the entrainment of the surrounding fluid (hereinafter referred to as negative pressure). It becomes. This region is indicated by L in the figure. When the center of the lens barrel opening is in the positive pressure region and the peripheral portion is in the negative pressure region as shown in FIG. 4B, a flow opposite to the desired thermal convection is formed depending on the degree of the pressure difference. To do. The above positive pressure / negative pressure region schematically shows a tendency of temporal / spatial average. Actually, the Reynolds number in the actual operation area of the elevator varies due to turbulent flow or Karman vortex. However, if the temporal / spatial average continues to be positive / negative pressure, it will cause backflow.

  Therefore, a deflector 0252 is newly provided as shown in FIG. Even when the moving direction of the lens barrel is 0251, the deflector forms a positive pressure region in almost all the region of the lens barrel opening, so that a desired heat convection direction can be maintained. This is because the negative pressure region due to the entrainment of the surrounding fluid is formed further outside the periphery of the lens barrel opening due to the action of the deflector. On the other hand, even when the movement direction of the lens barrel is 0250 with the deflector as shown in FIG. 10 (c), positive pressure is applied in almost all regions of the lens barrel opening. The direction of convection can be maintained. Further, as described above, the positive pressure region formed here has a temporal / spatial average tendency, and is therefore fluctuated by turbulence or the like. However, since the fluid forming the thermal convection in the lens barrel has inertia, the influence of the above fluctuation can be reduced. The inertia of the fluid and the flow velocity of the heat convection can be increased by extending the length of the lens barrel, and thus are adjusted as appropriate according to the application environment of the lens barrel. An example of a deflector shape capable of realizing the above functions within a standard elevator operating speed range is shown in FIG. An example of the value of D is 0.05 m. Each dimension d need not be exactly the same value.

  The shape of the lens barrel is not necessarily a double cylinder as long as the necessary heat convection flow rate can be obtained and the effect of preventing the adhesion of dust on the optical window surface can be obtained. For example, as shown in FIG. 4, by using a lens barrel having a rectangular cross section, advantages such as improvement in production and use of a planar heat generation / absorption element can be expected.

  FIG. 5 is an example of selecting an optical window arrangement location. Since the mass of the dust is not 0, it cannot follow the flow due to inertia near the point where the direction of the flow vector of the in-cylinder fluid changes, and adheres to the vicinity of a specific location. In FIG. 9A, when the location where dust accumulates by heat convection in the lens barrel is 0253, the optical window can be provided at the position P or Q in FIG. Similarly, in the case where the shape of the lens barrel is another shape such as a double cylinder, the optical window is arranged avoiding accumulation of dust. Even in the case of a symmetrical lens barrel shape, dust accumulation is not always symmetrical. This is because there is a bias in the flow velocity distribution around the lens barrel due to the structure generally present around the lens barrel. Therefore, the above characteristics are taken into consideration when arranging the optical windows. The location 0253 where the dust accumulates can be predicted by calculation in addition to the experiment. When the optical axis can be shifted between the light emitting element and the light receiving element, as shown in FIG. 5B, the optical window for the light emitting unit 0254 and the optical window for the light receiving unit 0255 are placed at different locations. Can be arranged. In particular, when a semiconductor laser is used as the light emitting element, the diameter of the optical window on the light emitting side can be reduced, so that the degree of freedom of the optical window installation position is increased. This is advantageous when the portion where the dust accumulation location 0253 is avoided is narrow.

  FIG. 9 shows an example in which natural cooling is used as the cooling means. In general, a Peltier element that can perform both cooling and heating is more expensive than a heater that performs only heating. Therefore, if a heater is used as the heating means and the cooling is natural cooling, the apparatus can be configured at low cost. In FIG. 9, the heat in the lens barrel is cooled by using the heat radiating means 0258-2 in the lens barrel connected to the heat radiating means 0258-1 outside the lens barrel by the heat transfer means 0256. The heating means 0208 is composed of an element having only a heat generating action such as a heater.

  FIG. 10 shows the effect of the channel cross-sectional area ratio. A cross section AA ′ of the lens barrel 0207 is shown in the lower part of FIG. Although illustration of the heating / cooling means is omitted, the direction of the heat convection is a downward flow on the inside of the flow path separation wall 0216 and an upward flow on the outside. Assuming that the cross-sectional area inside the flow path separation wall 0216 is Sd and the cross-sectional area of the portion surrounded by the flow path separation wall and the lens barrel is Sa, the ratio Vd / Va between the downward flow speed Vd and the upward flow speed Va. Is approximately Sa / Sd. For example, if the cross-sectional area Sd of the downward flow portion is half of the cross-sectional area Sa of the upward flow portion, the flow velocity of the downward flow is approximately twice the flow velocity of the upward flow. When the flow velocity of the downward flow portion is large, the probability that particles enter the front surface of the optical window 0206 via the vicinity of the central axis of the lens barrel from the lens barrel opening can be reduced.

  FIG. 11A shows an example of control of the heating / cooling means. In this embodiment, the temperature of the wall surface on which the heating unit 0208 and the cooling unit 0212 are installed is controlled to a preset value. Here, it is assumed that heating and cooling can be independently controlled. The temperature sensor 0220 detects the temperature of the wall surface where the target heating / cooling means is installed. When the temperature of the fluid adjacent to the wall surface is measured, measures such as filter processing may be taken because the measured value tends to fluctuate. The detected value is compared with the set temperature held in the temperature set value holding means 0221 using the temperature comparison means 0222, and the heating / cooling means is driven by the drive means 0223 as necessary. In the figure, -H attached to the symbol indicates a heating means, and -L indicates a control means corresponding to the cooling means. Tref.H and Tref.L are temperature setting values corresponding to the heating means and the cooling means, respectively. Tref.H is, for example, the temperature of the lens barrel surrounding fluid measured using the ambient temperature sensor 0224 + ΔTh, and Tref.L is set to the temperature of the lens barrel surrounding fluid−ΔTl. Now, assuming that ΔTh = 10 ° C. and ΔTl = 10 ° C. in a cylindrical lens barrel having a height of about 0.5 m and an outer diameter of 0.05 m, if the wall friction is neglected, the downward flow is about 0.5 m / s. Can be generated. The descending flow velocity in the lens barrel is not necessarily higher than the moving speed of the lens barrel. This is because the pressure of the fluid around the lens barrel that accompanies the movement acts on the downward flow portion and the upward flow portion of the lens barrel opening similarly. Further, the absolute values of ΔTh and ΔTl are not necessarily equal. In addition, ΔTh and ΔTl may be changed according to the moving speed of the moving object on which the optical sensor unit 0203 is installed. In this case, in consideration of the thermal time constant, ΔTh and ΔTl may be started to increase / decrease at a stage before the time when the moving body is predicted to start moving to form an appropriate temperature difference. In the case of an elevator, there are many means that can easily analogize the movement start time of the car, such as pushing down the door closing button in the car and the door closing time-out. Prior to the transfer start time, a larger flow rate of thermal convection is formed due to a larger temperature difference. Conversely, when the moving body does not operate for a while, energy consumption may be reduced by using thermal convection with a smaller flow velocity.

  The ambient temperature sensors 0224-H and 0224-L may share one sensor. The temperature sensor is installed at a location where heat from the heating unit 0208 and the cooling unit 0212 is not affected. Further, a plurality of ambient temperature sensors 0224 may be installed in a hoistway that is a movement range of the car 0105. Among the measured values of a plurality of ambient temperature sensors, when the maximum temperature is T-EnvMax and the minimum temperature is T-EnvMin, T-EnvMax is used for calculating Tref.H, or T-EnvMax is calculated for calculating Tref.L. By applying at least one of using EnvMin, it contributes to stable generation of thermal convection in the lens barrel.

  In FIG. 11A, the temperature control of both the heating unit 0208 and the cooling unit 0212 is performed. However, at least one of the control units may be controlled. For example, when a Peltier element is used as the heating / cooling means, it is preferable to control the temperature of only the heating means 0208. FIG. 11B is an example in which only the heating means 0208 is controlled. Since the amount of heat generated by the Peltier element reaches several times the amount of heat absorption, if the temperature control is performed only on the cooling means side, the temperature on the heating means side may exceed the appropriate temperature of the optical sensor unit 0203 related equipment such as a lens barrel. There is. Therefore, the temperature control on the heating unit 0208 side is performed, and the cooling side uses the heat absorption amount corresponding to the heat generation amount set in the heating unit as it is. Even in this case, the cooling means generates a downward flow in order to relatively lower the temperature of the fluid in the lens barrel, and it is possible to form a thermal convection in the lens barrel together with the upward flow on the heating means side.

  FIG. 12 shows an example of heating / cooling means control based on the flow rate. In this configuration, by comparing the flow velocity value obtained by the flow velocity sensor 0260 with the flow velocity set in the flow velocity set value holding unit 0261 using the flow velocity comparison unit 0262, the flow rate of the thermal convection in the lens barrel is within an appropriate range. Control. The driving unit 0223 drives at least one of the heating unit 0208 or the cooling unit 0212. This method can be expected to have a more direct effect by using the flow rate of thermal convection, which is the source of the anti-smudge function of the optical sensor unit, as a controlled variable. On the other hand, due to the influence of the turbulent flow near the opening of the lens barrel, the fluctuation of the detected value of the flow velocity sensor becomes large, and there is a possibility that a filter with a large time constant is required. If the installation position of the flow velocity sensor 0260 is on the upward flow side, there is an advantage that the optical path on the front surface of the optical window 0206 is less likely to be an obstacle. If the installation position of the flow velocity sensor 0260 is set to the downstream flow side, it is advantageous in terms of detection sensitivity when applying the thermal convection acceleration by the cross-sectional area ratio shown in FIG. In addition, since the position where the flow velocity sensor is installed is behind the optical window on the flow path, the possibility of disturbing the streamline near the optical window due to the turbulent flow generated by the flow velocity sensor can be reduced.

  The lens barrel opening desired from the optical window does not necessarily have to be directed in the direction of gravitational acceleration. FIG. 14 is a diagram illustrating the relationship between the direction of the lens barrel opening and the direction of gravity. When dust and oil and fat mist can be prevented from adhering to the optical window only by thermal convection, the lens barrel opening is directed in the direction opposite to the gravitational acceleration (upward) as shown in Figs. It is possible to make it. By not limiting the directing direction of the lens barrel opening downward, the degree of freedom in configuring the optical sensor unit 0203 increases. For example, when used for an elevator, the optical target 0219 can be installed above the hoistway. This configuration is advantageous when it is more difficult to prevent the optical target 0219 from being contaminated than the optical sensor unit 0203. As shown in FIGS. 14C and 14D, thermal convection can be generated even when the lens barrel opening is inclined or orthogonal to the direction of gravitational acceleration. When the lens barrel opening is in an oblique direction, it can be used for a moving body whose moving direction is oblique with respect to gravitational acceleration, such as a slanting elevator or escalator. This can be used when there is a detection target on the hoistway wall in the oblique direction. The same applies to the case where the opening is perpendicular to the gravitational acceleration direction. For example, it can be used when detecting a detection target such as a barcode or an optical marker installed on the side wall of the hoistway from a general elevator that is not skewed. Further, the present invention is not limited to the embodiment shown in FIG. 14, and the dirt prevention method of this embodiment can be applied to the case where the optical sensor unit 0203 is installed in a place other than the car, such as a hoistway wall.

  FIG. 15 shows an application example of the particle trap. By providing the particle trap shown in FIG. 0263 before reaching the optical window on the flow path, the number of particles reaching the vicinity of the optical window is reduced. In addition to the labyrinth structure, the particle trap may be a filter or the like if pressure loss is appropriate. The difference between the pressures P1 and P2 before and after the particle trap may be used to also serve as a part of the function of the flow velocity detection means.

The elevator block diagram by one Embodiment of this invention. The block diagram of the optical sensor unit by one Embodiment of this invention. The figure which shows the example which uses the deflector by one Embodiment of this invention. The figure which shows the flow-path shape by one Embodiment of this invention. The figure which shows the example of the optical window arrangement | positioning location selection by one Embodiment of this invention. The figure which shows the example of the heating / cooling means installation place by one Embodiment of this invention. The figure which shows the example of the waste heat means by one Embodiment of this invention. The figure which shows the example of the shunt of the waste heat by one Embodiment of this invention. The figure which shows the example using the natural cooling means by one Embodiment of this invention. The figure which shows the effect by the flow-path cross-sectional area ratio by one Embodiment of this invention. The figure which shows the example of the heating / cooling means control by one Embodiment of this invention. The figure which shows the example of the heating / cooling means control by one Embodiment of this invention. The figure which shows the example of a deflector shape. The figure which shows the relationship between a lens-barrel opening part direction and a gravity direction. The figure which shows the example of application of the particle | grain trap by one Embodiment of this invention. The figure which shows the speed limit pattern at the time of utilization of the termination | terminus floor reduction gear apparatus by one Embodiment of this invention.

Explanation of symbols

0102 guide rail 0105 car (car)
0106 Main rope 0107 Balance weight 0108 Hoisting machine 0109 Brake 0111 Control device 0114 Emergency stop device 0201 Car side control device 0203 Optical sensor unit 0204 Other sensor 0205 Optical sensor 0206 Optical window 0207 Lens barrel 0208 Heating means 0209 Fluid in the barrel 0211 Gravity acceleration Direction 0212 Cooling unit 0213 Upflow forming unit 0214 Downflow forming unit 0216 Channel separation wall 0219 Optical target 0220 Temperature sensor 0221 Temperature set value holding unit 0222 Temperature comparing unit 0223 Driving unit 0224 Ambient temperature sensors 0250, 0251 Deflector
0253 Dust accumulation location 0254 Light emitting unit 0255 Light receiving unit 0256 Heat transfer means 0257 Heat flux 0258 Heat flux 0260 Flow rate sensor 0261 Flow rate set value holding means 0262 Flow rate comparison means 0263 Particle trap 0301 Rated speed 0302 Limit speed 0303, 0304 Operating range

Claims (9)

  An optical sensor device having an optical sensor or an optical window at a position where the lens barrel opening is desired via the fluid in the lens barrel, the optical sensor device having an opening with respect to the surrounding fluid, An optical sensor device comprising means for heating or cooling the fluid.   An optical sensor device having a lens barrel having an opening with respect to the surrounding fluid, the means for causing thermal convection in the fluid in the lens barrel, and the amount of dust deposited in the lens barrel by the thermal convection. An optical sensor or an optical window is arranged at a position where the lens barrel opening is desired from a location where the amount of dust accumulated is relatively small, depending on the position in the lens barrel and making it non-uniform. An optical sensor device.   3. The optical sensor device according to claim 1, further comprising a structure in the lens barrel that separates a heat convection flow path in the lens barrel along a length direction of the lens barrel.   4. The optical system according to claim 1, wherein the entire region of the lens barrel opening is less than the pressure of the surrounding fluid in both cases where the optical sensor device moves in the desired direction of the opening from the optical sensor or the optical window and vice versa. An optical sensor device comprising a baffle for guiding ambient fluid so as to be in a relatively high region.   5. The apparatus according to claim 1, wherein at least a means for detecting a temperature of a wall surface or fluid in the lens barrel, a means for comparing a temperature measurement value with a temperature set value, a means for heating or cooling the lens barrel. An optical sensor device having one side and means for driving them.   5. The apparatus according to claim 1, wherein at least one of means for detecting a flow velocity of the fluid in the lens barrel, means for comparing the flow velocity measurement value with the flow velocity setting value, means for heating the lens barrel, and means for cooling the lens barrel; An optical sensor device having means for driving them.   7. The optical sensor device according to claim 1, wherein a ratio of a length from the opening end of the lens barrel to the optical sensor or the optical window with respect to the lens barrel opening diameter is 3 or more.   A mobile system comprising the optical sensor device according to claim 1.   An elevator system comprising the optical sensor device according to claim 1.

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