JP4783816B2 - Apparatus for measuring coefficient of friction on lid surface for underground structure and method of use - Google Patents

Description

  The present invention relates to an apparatus for measuring a friction coefficient of a surface of a cover for an underground structure against a vehicle tire and a method for using the apparatus.

  Since there is no end to the accident of a two-wheeler falling on a manhole iron cover that has become wet due to rainfall, various measures are being sought. It is common knowledge for those who use motorcycles to be careful with wet iron covers, but this is not always well known to motorbike class users. The coefficient of friction of asphalt pavement in rainy weather is around 0.45-0.6, while the coefficient of friction in wet metal products such as manhole iron covers is around 0.2, and the coefficient of friction on the road Will suddenly change. For this reason, in particular, in a motorbike class with low running stability, even a slight slip is likely to cause a fall, and there is a possibility of an unexpected major accident when sliding.

  Iron lid manufacturers are taking measures such as forming an anti-slip pattern with uneven patterns on the surface of the iron lid, filling it with anti-slip paint to prevent slip, or calling attention by coloring. Since the design of the concavo-convex pattern differs from city to city, the anti-slip performance is not the same, and it is necessary to confirm the friction coefficient when using the iron lid. Although there are various techniques for measuring the slip resistance, Patent Nos. 1129813, 1641983, and 1671471 related to DF tester (trademark) of Nihon Sangyo Co., Ltd. defined in ASTM: E-1911-98. The invention can automatically record the relationship between the friction coefficient and the speed from various conditions when the road surface friction measurement rubber body is rotated and brought into contact with the road surface. This is one standard indicator as can be understood from the standardization, but it uses a rubber body or a similar measuring member, such as a motorcycle tire and a manhole cover. It is not suitable for measuring the coefficient of friction with the surface.

  In addition, ASTM: E-303-93 has a measuring instrument called “BPN testing machine”, which is a “method for measuring surface friction characteristics using an English pendulum sliding resistance testing machine”. A portable version of OY PSM (original machine) developed at the Tohoku Institute of Technology Hidetomo Ono Laboratory in 1984 is known. However, these both evaluate the slip on the pedestrian (shoe) and the pavement or flooring, and the speed range is different, which is suitable for measuring the friction coefficient between the motorcycle tire and the manhole cover. Not to say.

  Japanese Patent Laid-Open No. 10-38791 is an invention that aims to detect the static friction coefficient and the dynamic friction coefficient of the lid surface of the underground structure container lid with high accuracy. It is pointed out that there is an extreme difference in the measured value due to the combination of the ruggedness and the uneven pattern on the iron lid surface. The invention of Japanese Patent Application Laid-Open No. 2003-232721 is said to be a dynamic friction coefficient measuring device that can accurately measure even a surface to be measured with severe irregularities. However, to measure for 3 seconds at a speed of 30 km per hour, a distance of several tens of meters is necessary, and an iron lid having a diameter of about 0.6 meters cannot be measured. Thus, in the conventional measuring method and apparatus, the measuring unit is different from the actual one, and an approximate value is measured. The large slip test vehicle used by the JH Test Laboratory (Japan Highway Public Corporation) is supposed to be able to obtain the correct measurement result because the measurement tire is brought into contact with the road while running, so that it is possible to obtain the correct measurement result. The time for passing through the surface of the structural iron lid is extremely short, and accurate measurement cannot be desired.

JP-A-53-57082 JP 60-6847 JP 60-149946 A JP 10-38791 A JP 2003-232721 ASTM: E-1911-98 ASTM: E-303-93

  This invention is made paying attention to the said point, The subject is measuring the friction coefficient of the cover body surface for underground structures with respect to a vehicle tire correctly. Another object of the present invention is to make it possible to measure a dynamic friction coefficient with respect to the surface of a lid of a tire of a two-wheeled vehicle, for example, which travels on the surface of a cover for an underground structure in a state close to actual traveling. . Another object of the present invention is to provide an apparatus for measuring a friction coefficient on the surface of a lid for an underground structure that is as small as a manhole iron lid and is practical. Another object of the present invention is to realize a method capable of freely controlling the measurement time of the friction coefficient.

In order to solve the above-described problems, the present invention provides an apparatus for measuring the friction coefficient of the surface of a lid for an underground structure against a vehicle tire , a table on which the measurement lid is arranged substantially horizontally, and a surface of the measurement lid A main shaft arranged almost perpendicular to the upper part of the measurement lid so as to take an arrangement substantially perpendicular to the center, and a fixed axis provided at the lower end of the main shaft with an arrangement perpendicular to the axial direction of the main shaft. A rotating shaft for attaching the measurement tire to the fixed shaft, provided in the radial direction with the main shaft as a center, and so that the measurement tire goes around a path set only on the surface of the measurement lid; It consists of an elevating mechanism for arranging the measurement lid and the measurement tire so that they can be relatively contacted and separated so that the measurement tire contacts and rotates on the surface of the measurement lid. As a lid for underground structures Use the usable and, as a measure tire, indeed may be used as a vehicle tire, and creates a condition close to the actual running by using one driving possible, rotating the measurement tire When the vehicle is locked from the state by the braking mechanism, a measure is taken to calculate the friction coefficient based on the contact load generated on the measurement tire measured by the load cell and the friction force. .
In addition, the present invention is a device for measuring the friction coefficient of the surface of the lid for an underground structure with respect to a vehicle tire, and a table on which the measurement lid is arranged substantially horizontally and substantially orthogonal to the center of the measurement lid The main shaft is disposed substantially perpendicular to the upper part of the measurement lid, the base is provided at the lower end of the main shaft, and the main shaft is disposed on the base. The measurement tire is in contact with the surface of the measurement lid and the rotating shaft for mounting the measurement tire so that the measurement tire circulates on a path set only on the surface of the measurement lid and is provided in the radial direction as the center. And a lifting mechanism for disposing the measurement lid and the measurement tire so that they can be relatively contacted and separated from each other, and can be used as a lid for an underground structure as a measurement lid. Use things or When a measurement tire that is actually usable as a vehicle tire and capable of running is used to create conditions close to actual running, and the measuring tire is locked from a rotating state by a braking mechanism The means for calculating the friction coefficient based on the contact load and the friction force generated in the measurement tire measured by the load cells is provided.

  One object of the friction coefficient measuring apparatus according to the present invention is to measure the friction coefficient of the surface of a cover for an underground structure against a tire of a two-wheeled vehicle as accurately as possible. For example, a tire for a 10-inch wheel of a moped bicycle passing through the surface of a manhole iron cover having a standard diameter of φ600 mm may be considered as a typical size for carrying out the present invention. In the present invention, in order to carry out measurement in a state close to actual traveling, a thing having a surface unevenness pattern that can actually be used as a cover for an underground structure is used as a measurement cover, and actually as a tire for a motorcycle. What can run is used as a measurement tire. In other words, the actual measurement lid and measurement tire are used for the measurement, and air of a predetermined pressure is injected into the measurement tire. Of course, a small tire for a light vehicle or a tire of a size that can be rotated on the surface of a cover for an underground structure can be a measurement tire.

  In the present invention, a configuration is adopted in which the measurement lid and the measurement tire are arranged so as to be relatively contacted and separated by the lifting mechanism so that the measurement tire contacts and rotates on the surface of the measurement lid. Because it is relative, the lifting mechanism either raises or lowers the table supporting the measurement lid relative to the measurement tire, or raises or lowers the measurement tire relative to the measurement lid by axial movement of the main shaft. One or both of the configurations can be taken (the invention according to claim 2). In other words, the table supporting the measurement lid can be moved up and down with respect to the measurement tire, and the measurement tire can be moved up and down with respect to the measurement lid by moving the main shaft in the axial direction. Permissible.

  In the present invention, the rotation of the main shaft that is arranged substantially orthogonal to the center of the measurement lid surface causes the measurement tire to go around a path set on the surface of the measurement lid, thereby creating conditions close to actual running. . When the measurement lid is a circular iron lid, the main shaft is arranged at a position that coincides with the center of the circle. In the case of a square iron lid, the main axis is arranged so as to coincide with the intersection of the diagonal lines. Further, the main shaft has a sleeve joint composed of a fixed shaft provided in the radial direction around the main shaft and a rotating shaft rotatable with respect to the fixed shaft, and the measurement tire is attached to the rotating shaft constituting the sleeve joint. It is preferable that the braking mechanism and the load cell are arranged on the fixed shaft side (the invention according to claim 3). This sleeve joint can also have a structure that can be rotated around the axis of the cylinder axis and the cylinder axis and can be slid in the axial direction (radial direction). In order to be able to adjust the rotation radius of the measurement tire, the rotation radius of the sleeve joint can be changed by changing the rotation axis of the sleeve joint according to the size of the measurement lid, or the rotation axis can be changed by an expansion / contraction mechanism during measurement. Can be moved in the axial direction to change the radius of rotation so that it can be selectively changed according to the size of the measurement lid, or a measurement over a wide range on the lid surface can be performed. This becomes possible (the invention according to claim 4).

  The sleeve joint can be provided in two radial directions (diameter direction) with the main shaft as the center. One of the sleeve joints is provided with a measurement tire, and the other is provided with a counter tire for balancing the load. (Invention of claim 5) The manhole iron cover is generally a taper fitting lid that causes the outer peripheral surface of the lid and the inner peripheral surface of the receiving frame to be tapered, but there is also an iron lid with insufficient taper fitting. There is an iron lid called a flat support that does not bite. If an iron cover with insufficient fitting is used, it can be assumed that the opposite side of the tire grounding part will lift up and the test cannot be performed. The test can be performed without any trouble.

  When the measurement tire is locked by the braking mechanism from the rotating state, the friction coefficient is calculated based on the ground contact load and friction force generated on the measurement tire measured by the load cells. While it is not impossible to measure the ground contact load and friction force even after reaching the lock after braking, if it is difficult to take a correspondence with speed, etc., qualitatively know the tendency of the friction force change from the start of braking to the lock. It can be used for that. As the load cells, a pressure gauge, a strain gauge (strain gauge), and the like can be used. The above measurement can be carried out in a dry state or a wet state, and in order to cope with the latter case, a water supply device for bringing the surface of the measurement lid into a wet state is provided (the invention according to claim 6). .

  The main shaft has a base that is arranged almost horizontally at the lower end of the main shaft, and the base has a tire set mounting portion at a predetermined radius centered on the main shaft. And can be configured to be attached to and detached from the mounting portion of the base together with the fork (invention of claim 7). The base is provided for attaching the tire set, and can take a form such as a straight line as well as a disk form. In the case of a disk-like form, the weight is somewhat soft but the moment of inertia is large, so the tendency to decrease the spindle speed during braking is eased, and the disturbance of rotational balance is reduced due to the shape of the disk, and the friction coefficient is measured. This is also advantageous in terms of preventing vibration of the entire apparatus. On the other hand, in the case of the linear form, the rotating portion can be reduced in weight, but there are advantages and disadvantages such as a relatively small moment of inertia.

  It is significant that the tire is mounted on the fork to form a tire set and can be handled as a tire set. In other words, it is sufficient to use at least one bolt and at most two bolts to attach the fork, so the number of hub bolts is less than the number of hub bolts. Tires can be easily replaced without loosening or tightening the tires one by one. In addition, by providing several attachment points in the radial direction, it is possible to easily change the rotation radius of the tire that circulates around the measurement lid surface.

  Torque detection load cells are arranged between the main shaft and the base attached to the lower end thereof, and the table supporting the measurement lid is composed of two upper and lower tables, and load detection load cells are arranged between the upper and lower tables. It is a desirable configuration to take the configuration arranged (the invention according to claim 8). If load cells are installed near the tires, the surface of the measurement lid may get wet due to water supply, which may impair the durability of the load cells. If used, the structure may be complicated and expensive, and the damage is not small. On the other hand, load cells are divided into load detection and torque detection, load detection cells are arranged between the base on which the tire set is mounted and the main shaft, and the load is detected under the table that supports the measurement lid. By arranging the load cells for use, there is no risk of getting water. In addition, two types of load cells for torque detection and load cells for load detection are required, but there are many advantages such as being relatively simple and inexpensive and easy to handle.

  Making the table that supports the measurement lid with two upper and lower tables contributes to improvement in measurement accuracy. That is, since the table receives a rotational force due to the tire drag torque, if load cells are arranged directly on the table, a lateral force other than the ground load is applied to the load cells, which causes a reduction in measurement accuracy. For this reason, with respect to the upper table that rotates slightly upon receiving the rotational force, for example, it is engaged with four struts constituting the apparatus to receive the rotational force, and the load cells are installed on the lower table that does not receive the rotational force. By adopting a configuration in which the load cells and the upper table are connected to each other by a spherical washer or the like, the lateral force that affects the measurement accuracy can be eliminated from the load cells. Therefore, load cells for detecting a ground load are arranged at three locations (stable points for determining a plane) on the lower table, and the lower table is supported by, for example, four lifting devices, so that the load can be distributed.

Furthermore, according to the present invention, a table for arranging the measurement lid substantially horizontally, and a main shaft arranged substantially vertically on the top of the measurement lid so as to take an arrangement substantially perpendicular to the center of the surface of the measurement lid. A fixed shaft or base provided at the lower end of the main shaft with an arrangement perpendicular to the axial direction of the main shaft, provided on the fixed shaft or base in the radial direction about the main shaft, and a measurement tire The measurement lid and measurement are performed so that the measurement tire contacts the surface of the measurement lid and rotates so that the measurement tire circulates the path set only on the surface of the measurement lid. It is composed of an elevating mechanism for arranging the tires so that they can be relatively contacted and separated from each other, and as a measurement lid, what can actually be used as a lid for an underground structure is used, and actually as a measurement tire As vehicle tires It is possible to use the measurement tire measured by the load cell when the measurement tire is locked by the braking mechanism from the rotation state by creating a condition close to the actual traveling by using the one that is usable and capable of traveling. A method of using a friction coefficient measuring device having a configuration for calculating a friction coefficient based on a generated ground load and friction force, and rotating a main shaft while keeping a measurement tire locked, thereby freely measuring time. It is possible to take a method of being configured to be controllable.
In addition, the present invention is a device for measuring the friction coefficient of the surface of the lid for an underground structure with respect to a vehicle tire, and a table on which the measurement lid is arranged substantially horizontally and substantially orthogonal to the center of the measurement lid The main shaft is disposed substantially perpendicular to the upper part of the measurement lid, the base is provided at the lower end of the main shaft, and the main shaft is disposed on the base. The measurement tire is in contact with the surface of the measurement lid and the rotating shaft for mounting the measurement tire so that the measurement tire circulates on a path set only on the surface of the measurement lid and is provided in the radial direction as the center. And a lifting mechanism for disposing the measurement lid and the measurement tire so that they can be relatively contacted and separated from each other, and can be used as a lid for an underground structure as a measurement lid. Use things or When a measurement tire that is actually usable as a vehicle tire and capable of running is used to create conditions close to actual running, and the measuring tire is locked from a rotating state by a braking mechanism In the method of using a friction coefficient measuring device having a configuration for calculating a friction coefficient based on a contact load generated on a measurement tire measured by a load cell and a frictional force, the main shaft while the measurement tire is locked The measurement time can be freely controlled by rotating the.

  The apparatus according to claim 1 can be used so that the measurement time can be freely controlled by rotating the main shaft while the measurement tire is locked, which uses the apparatus according to the present invention. This is the first thing that can be realized, and the characteristics of the present invention can be seen here.

  Since the present invention is configured and operates as described above, the friction coefficient of the surface of the lid for the underground structure against the vehicle tire is measured using the actual measurement lid and the actual measurement tire. There is an effect that it is possible to measure accurately by circling the path set on the surface. In addition, according to the present invention, it is possible to measure, in particular, a dynamic friction coefficient of a vehicle tire that travels on the surface of the lid for an underground structure under conditions close to actual traveling. Further, according to the present invention, it is possible to provide a friction coefficient measuring device on the surface of a cover for an underground structure that is as small as a manhole iron cover and is practical. Further, according to the present invention, since the tire can be handled as a tire set mounted on a fork, the tire replacement is greatly facilitated, and the table supporting the measurement lid is composed of two upper and lower tables, and torque detection. Since the load cells for load and the load cells for load detection can be arranged separately, the degree of freedom of the device configuration is increased and the accuracy is also improved.

  Hereinafter, the friction coefficient measuring device 10 on the surface of a lid for an underground structure according to the present invention will be described in more detail with reference to the illustrated embodiment. 1 to 3 show an apparatus of Example 1 according to the present invention, and a manhole iron cover having a standard diameter of φ600 mm, which is actually used as a cover for an underground structure, is used as a measurement cover 11. The manhole iron cover of Example 1 is a taper fitting lid that causes a taper fitting with the inner tapered surface of the receiving frame 12 at the outer tapered surface, and the receiving frame 12 is installed on the table 13. Is provided so as to be movable up and down by an elevating mechanism 14. An uneven pattern 11a having a height difference of about 6 mm is formed as a non-slip on the surface of the measurement lid 11, and the friction coefficient due to this non-slip is matched with the friction coefficient on the asphalt pavement surface. In addition to the load setting applied to the measurement tire 15, the elevating mechanism 14 can cope with tire replacement and tire size conversion.

  In the present embodiment, an actual two-wheeled vehicle tire is used as the measurement tire 15 at a predetermined air pressure, and the test tire in Example 1 is a 10-inch wheel tire for a moped bicycle. The measurement tire 15 is disposed at the lower end of the main shaft 16 that is disposed substantially orthogonal to the center of the measurement lid surface. The lower end of the main shaft 16 of Example 1 is provided with a sleeve joint 19 including a fixed shaft 17 and a rotary shaft 18 fixedly attached in a radial direction around the main shaft 16, and the measurement tire 15 is the above-described rotation that constitutes the sleeve joint 19. The shaft 18 is easily attached and detached. The main shaft 16 is driven by a motor 20 and is rotated by bringing the measurement tire 15 into contact with the measurement lid. Thus, between the measurement tire 15 and the measurement lid 11, a condition close to the actual travel is created that goes around the path set on the lid surface. The rotation of the measurement tire 15 is a secondary rotation based on the main rotation of the main shaft 16, but can be driven in the same manner as an actual wheel.

  The lifting mechanism 14 may be configured to move the measurement tire 15 up and down by moving the spindle in the axial direction with respect to the table 13 supporting the measurement lid 11. FIG. 4 shows Example 2 in which an upper table 13a that is moved up and down by an elevating mechanism 14 is provided at the upper part of the apparatus frame, and a motor 20 and a main shaft 16 driven thereby are installed on the table 13a. Other configurations may be the same as those described above with reference to Example 1, so that reference numerals are used and detailed description will not be repeated.

  A braking mechanism 21 for locking the measurement tire 15 from the rotation state is installed between the fixed shaft 17 and the rotation shaft 18 constituting the sleeve joint 19, and the lid surface and the measurement tire 15 are locked when locked. In order to measure the friction force generated between them, load cells 22 composed of strain gauges are installed. In the case of illustration, the load cells 22 use a biaxial strain gauge capable of simultaneously measuring the tire ground contact load (f1) and the frictional force (f2), and the output is a PC (personal computer) that constitutes the measuring device calculation unit. In the measurement device calculation unit, the data regarding the measured frictional force is calculated by predetermined software together with the data of the ground load generated on the measurement tire 15. On the other hand, it is possible to easily measure the ground load and the frictional force separately using two strain gauges for one axis (see FIG. 7).

  The device 10 of the present invention includes a water supply device 23 for bringing the surface of the measurement lid 11 into a wet state. An example water supply device 23 is provided with a large number of nozzles 25 on the inner periphery of a sprinkling pipe 24 formed in a ring shape substantially the same shape as the measurement lid 11 to spray water on the surface of the measurement lid 11. 24a shows a water supply part. A large number of nozzles 25 are formed in different directions so that the entire surface of the lid body gets wet evenly and quickly. The water supply device 23 can create a wet state on the ground contact surface of the measurement tire 15 (see FIG. 5). In addition, the connection part of the water supply part 24a becomes a gas-liquid switching type | mold, and it becomes possible to switch now a dry state and a wet state rapidly.

  By making the rotation radius of the measurement tire 15 adjustable, the radius of the circuit path can be changed according to the size of the measurement lid 11. FIG. 6 shows Example 3 of the present invention, which is a system in which an extension shaft 26 having a similar connection flange 26a is interposed in a connection flange 18a provided at the tip of the rotary shaft 18 of the sleeve joint 19. According to the method, only by preparing a plurality of extension shafts 26 having different lengths, it is possible to adjust the size of the circumference path radius of the measurement tire 15 without requiring a mechanical change. FIG. 7 shows Example 4 of the present invention in which the circuit path radius can be dynamically adjusted, and the rotating shaft 18 is moved in the axial direction by a hydraulic mechanism (see FIG. 8), whereby the circuit path radius is externally operated. This is an example that can be changed. In FIG. 8, when a telescopic mechanism comprising a piston 18 'and a cylinder 17' is added to the sleeve joint 19, and when the hydraulic pressure pressurized by the pump is applied from the port 17a, the piston 18 'is pushed out and the measurement tire is measured. 15 is moved outward to increase the turning radius, or by removing the hydraulic pressure from the port 17a and making the inside of the cylinder 17 'a negative pressure, the measurement tire 15 is pushed back at atmospheric pressure to reduce the turning radius. is doing. By adjusting the radius of the circular path in this way, the width of the measurement range can be expanded as shown in the lower part of FIGS. 7A and 7B.

  The manhole iron cover is generally a taper fitting lid in which the outer peripheral surface of the lid body and the inner peripheral surface of the receiving frame are biting on the tapered surface, but as described above, the iron lid with insufficient taper fitting, There is also an iron lid called a flat support that does not bite, and when an insufficiently fitted iron lid is used, as shown in Fig. 9, the opposite side of the tire grounding part will be lifted up, making it impossible to test Therefore, it is possible to balance the load applied to the surface of the lid body by installing a counter tire in advance. FIG. 10 shows Example 5 of the apparatus of the present invention, in which sleeve joints 19 and 19 'are provided in two radial directions, that is, in a diametrical direction around the main shaft 16, and the measurement tire 15 is attached to one of the sleeve joints 19 therein. The other sleeve joint 19 'is provided with a counter tire 15' that balances the load, and the measurement tire 15 and the counter tire 15 'have the same radius of rotation. Also for Example 5, Example 2 (elevating device that can be installed up and down), Example 3 and Example 4 (Adjusting the size of the radius of the circular path) of the embodiment of the present invention shown so far can be applied.

  In order to use such an apparatus 10 of the present invention, the measurement lid 11 and the measurement tire 15 are first brought into contact with each other with an appropriate pressure by operating the lifting mechanism 14 by operating a control unit (not shown). FIG. 3 shows the above state. When the control unit is further operated in this state, the motor 20 is started and the main shaft 16 rotates, so that the measurement tire 15 pressed against the surface of the measurement lid body 11 starts rotating around the rotation axis, and at the same time the measurement is performed. The surface of the lid 11 is circulated by a preset path. Accordingly, the rotation of the measurement tire 15 is caused by friction with the lid body surface with the rotation of the main shaft 16.

When it is confirmed that the rotation of the measurement tire 15 has reached the specified speed, the braking mechanism 21 is activated by operating the control unit, and the measurement tire 15 is locked, depending on the coefficient of friction due to the uneven pattern 11a on the surface of the measurement lid. A tangential force is generated. At this time, the friction coefficient measurement time can be freely controlled by continuing the rotation of the motor 20, but this is a novel measurement method that is possible only by using the apparatus 10 of the present invention. Moreover, the effect peculiar to the present invention that the measurement tire 15 continues to go around the path set on the surface of the measurement lid 11 is an indispensable condition for accurate measurement. Moreover, ideal measurement results can be obtained because conditions close to actual driving are created. Under such conditions that are close to actual conditions, the contact load and the frictional force are detected by the load cells 22,
Friction coefficient = friction force (f2) / contact load (f1)
Is calculated by

  Furthermore, the apparatus 30 of Example 6 according to the present invention will be described with reference to FIG. The apparatus 30 of Example 6 also uses a manhole iron lid having a standard diameter of φ600 mm, which is actually used as a lid for an underground structure, as a measurement lid 11 and also a tire for a 10-inch wheel of a moped bicycle. Is the same as that of Example 1 in that it is a taper fitting lid, and the uneven pattern 11a having a height difference of about 6 mm is formed on the surface. The apparatus 30 of Example 6 is characterized in that a tire is a tire set 40 integrated with a fork 41, and a load cell for torque detection and a load cell for load detection are used as load cells. In addition, about a structure part which is common in Example 1 etc., a code | symbol is used and description is not repeated.

  In Example 6, the main shaft 31 connected to the motor shaft is a short shaft, a load cell 33 for torque detection is installed at the lower end of the main shaft 31 with a slip ring 32 interposed therebetween, and drag torque is measured. A base plate 34 is attached to the lower end portion thereof with a substantially horizontal arrangement perpendicular to the main shaft axis direction. As shown in FIG. 14, the base 34 has a disk shape with a large moment of inertia, and the tire set mounting portion 35 is used for measurement tires and counter tires at arbitrary positions on a line in the diameter direction of the disk. Are provided in two places. The tire set mounting portion 35 has three shaft holes 36a, 36b, 36c and an engaging groove 38 formed on the lower surface of the base along these hole rows, and the tire set 40 is attached to its mounting base 39. It is configured to be detachably attached. The counter tire mounting portion 35 'also has three shaft holes 36a', 36b ', 36c' and an engagement groove 38 'formed on the lower surface of the base along these hole rows. The tire set 40 includes a fork 41 and a tire 42 attached to the fork 41, and is engaged with the engagement groove 38 at the attachment base 39 to fit the bolts 37 into the shaft holes 36a to 36c. The same applies to the counter tire.

  Since the tire set mounting portion 35 can be provided at any position (36a to 36c) on the diameter direction line of the disk, Example 7 in FIG. 16A (assembled in the shaft hole 36c) and FIG. 16B (assembled in the shaft hole 36a). As shown in FIG. 4, a plurality of locations are prepared in accordance with different sizes of the measurement lid 11. Further, when only the measurement tire 42 is used, the measurement lid 11 can be lifted as a reaction of the ground load (FIG. 18). Accordingly, the tire set attachment portion 35 is provided at a symmetrical position on the line in the diameter direction of the disk, the measurement tire 42 is attached to one tire set attachment portion 35, and the counter tire 42 is attached to the other tire set attachment portion 35 ′. 'Can be mounted (FIG. 19). The tire set 40 is provided with a braking mechanism 45 that acts on the rotation shaft 44 of the measurement tire 42 attached to the fork 41 to lock the measurement tire 42 from the rotation state. However, braking is not necessarily required for the counter tire 42 '.

  In the apparatus of Example 6, the receiving frame 12 is installed on the upper table 46, which is composed of two upper and lower tables 46 and 47. The two upper and lower tables 46 and 47 are supported by an elevating mechanism 48 installed at four locations so as to be movable in the vertical direction. Here, since the upper table 46 is slightly rotated by receiving the rotational force by the tire drag torque, the upper table 46 is engaged with the four struts 49 constituting the apparatus frame at the four corners to receive the rotational force and receive the rotational force. The load cells 50 for load detection are installed at equal intervals on the lower table 47 that is not present, and the load cells 50 and the upper table 46 are connected to each other by a spherical washer 51 so as to be relatively movable (FIG. 20). Thereby, when the load cells are arranged directly on the table, a lateral force (lateral load) other than the ground load is applied to the load cells to prevent the measurement accuracy from being lowered.

  In the apparatus of Example 6, an upper table 52a that is moved up and down by an elevating mechanism 52 is provided on the upper part of the apparatus frame, and the entire tire set attached to the substrate 34 can be moved up and down (Example 8 in FIG. 17). reference). Therefore, in the example 8 of FIG. 17, the lifting mechanism 48 that lifts and lowers the lower table 47 is unnecessary. Reference numeral 53 denotes a support base, which may be provided as necessary. FIG. 21 shows a state in which a wet state is created on the ground contact surface of the measurement tire 15 by the water supply device 23. As is clear from the figure, the water sprayed from the water supply device 23 to the tire ground contact surface is the upper table. Since it does not reach the load detection load cells 50 arranged on the lower surface of 46, and does not reach the load detection load cells 33, the durability can be improved without impairing their functions. .

  In the invention according to Example 6 and the related configuration, since the measurement tire 42 is handled in units of the tire set 40, a tire that can actually run as a tire for a motorcycle is used as the measurement tire. In the present invention, the tire attaching / detaching operation, which is usually performed by tightening or loosening three, four or more hub bolts, is configured to attach or detach the fork 41 to the base 34, so that the number of the tire attaching / detaching operations is about one or two. Bolts can be attached and detached, and the effect of shortening the time and improving the measurement efficiency can be obtained. Also, by changing the turning radius of the measurement tire 42 by providing a plurality of tire set attachment portions 35 at different rotational radii. There is also an advantage that it can be easily handled. Example 6 In each of the following examples, the torque detection load cell 33 is arranged in relation to the mounting portion of the base 34 on which the tire set 40 is suspended, and the table supporting the measurement lid 11 is composed of two upper and lower tables. Since load detection load cells 50 are arranged between the upper and lower tables, it can be implemented without using multi-axis load detection load cells, and each load cell is located at a position where water spray is inevitable in the experiment. It is not necessary to worry about deterioration of durability due to water wetting. Further, the upper one of the upper and lower tables 46 and 47 can be rotated slightly, and a lateral force other than the ground load due to the drag torque of the measurement tire 42 can be absorbed, so that load cells for load detection are used. 50 can improve the measurement accuracy. In relation to the measurement accuracy, it is also possible to expect a contribution due to the moment of inertia of the disk-shaped base plate 34 and good rotation balance.

  As described above, in the present invention, a manhole iron cover surface having a standard diameter of φ600 mm, for example, a practical speed of 10 km / h to 30 km / h or more using a small-diameter tire such as a scooter type moped bicycle. The experiment can be repeated in the region, and the measurement time can be set freely. Furthermore, by using the water supply device 23 in combination, the experiment can be performed in either a dry state or a wet state.

  In addition, with respect to the method of the present invention in which the measurement tire contacts and rotates on the surface of the measurement lid 11, a method of fixing the tire side and horizontally rotating the iron lid side is also conceivable. However, in that case, the water supply by the water supply device is scattered around due to centrifugal force, resulting in a state different from the actual situation, causing a problem that the water film is cut. Further, it is necessary to firmly fasten the side of the iron lid to be rotated horizontally to the rotating device side. However, the method of the present invention in which the measurement lid 11 is fixed can be downsized as a whole and is therefore weak. This is advantageous because it only requires fastening.

The top view which shows Example 1 of the friction coefficient measuring apparatus in the cover body surface for underground structures which concerns on this invention. FIG. 3 is a side cross-sectional explanatory view showing the device. Side surface explanatory drawing which shows raising / lowering of the table in an apparatus same as the above. Side surface explanatory drawing which similarly shows Example 2 of the apparatus which concerns on this invention. Side surface explanatory drawing which shows the water supply state in this invention apparatus. FIG. 4 also shows Example 3 of the apparatus according to the present invention, in which A is a side cross-sectional explanatory view at a standard turning radius, and B is a side cross-sectional explanatory view at an extended rotating radius. Similarly, FIG. 4 shows Example 4 of the apparatus according to the present invention, in which A is a side cross-sectional explanatory view at a rotation radius before extension, and B is a side cross-sectional explanatory view at a rotation radius after extension. Explanatory drawing which shows an example of the mechanism which moves a rotating shaft to an axial direction. Explanatory diagram of a possible problem. Side surface sectional explanatory drawing which similarly shows Example 5 of the apparatus which concerns on this invention. The top view which similarly shows Example 6 of the apparatus which similarly concerns on this invention. Side surface explanatory drawing in an apparatus same as the above. Side surface explanatory drawing which shows raising / lowering of the table in an apparatus same as the above. The top view which similarly shows the base | substrate in the apparatus which concerns on this invention. The side view which similarly shows the relationship between a base | substrate, a tire set, and an underground structure. Similarly, FIG. 7 shows Example 7 of the apparatus according to the present invention, in which A is a side cross-sectional explanatory view at a standard turning radius, and B is a side cross-sectional explanatory view at an adjusted turning radius. Side surface sectional explanatory drawing which similarly shows Example 8 of the apparatus which concerns on this invention. Explanatory drawing which similarly shows the state which can occur in the driving | operation of the apparatus which concerns on this invention. Explanatory drawing regarding the example of the countermeasure of the state shown in FIG. The principal part expansion explanatory drawing of the thing of Example 6 of the apparatus which concerns on this invention. Side surface explanatory drawing which shows the water supply state in the same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Friction coefficient measuring device 11 Measuring lid 12 Receiving frame 13 Table 14 Lifting mechanism 15 Measurement tire 15 'Counter tire 16 Main shaft 17 Fixed shaft 18 Rotating shaft 19, 19' Sleeve joint 20 Motor 21 Braking mechanism 22 Load cell 23 Water supply device 24 Sprinkling pipe 25 Nozzle 26 Extension shaft 30 Friction coefficient measuring device 31 Main shaft 32 Slip ring 33 Torque detection load cells 34 Base 35 Tire set mounting portion 35 'Counter tire set mounting portion 36 Shaft hole 37 Bolt 38 Engaging groove 39 Mounting base 40 Tire set 41 Fork 42 Measurement tire 44 Rotating shaft 45 Braking mechanism 46, 47 Table 48 Lifting mechanism 49 Strut 50 Load detection load cell 51 Spherical washer 52 Lifting mechanism 53 Support base

Claims (11)

An apparatus for measuring a coefficient of friction of a lid surface for an underground structure against a vehicle tire,
A table on which the measurement lid is arranged almost horizontally;
A main axis arranged substantially perpendicular to the upper part of the measurement lid so as to take an arrangement substantially perpendicular to the center of the measurement lid surface,
A fixed shaft provided at the lower end of the main shaft, with an arrangement perpendicular to the axial direction of the main shaft;
A rotating shaft for attaching the measurement tire so that the fixed tire is provided in a radial direction with the main shaft as a center, and the measurement tire goes around a path set only on the surface of the measurement lid,
It is composed of an elevating mechanism for arranging the measurement lid and the measurement tire so that they can be relatively contacted and separated so that the measurement tire contacts and rotates on the surface of the measurement lid ,
By using a measurement lid that can actually be used as a lid for an underground structure , and a measurement tire that can actually be used as a vehicle tire and that can travel Create conditions close to actual driving,
When the measurement tire is locked from a rotating state by a braking mechanism, the lid for an underground structure has a configuration for calculating a friction coefficient based on a ground load and a friction force generated on the measurement tire measured by load cells. Coefficient of friction measurement device on the surface. An apparatus for measuring a coefficient of friction of a lid surface for an underground structure against a vehicle tire,
A table on which the measurement lid is arranged almost horizontally;
A main axis arranged substantially perpendicular to the upper part of the measurement lid so as to take an arrangement substantially perpendicular to the center of the measurement lid surface,
A base provided at the lower end of the main shaft with an arrangement perpendicular to the axial direction of the main shaft;
A rotating shaft for mounting the measurement tire so that the measurement tire circulates on a path set only on the surface of the measurement lid, provided in the radial direction around the main axis on the base ,
It is composed of an elevating mechanism for arranging the measurement lid and the measurement tire so that they can be relatively contacted and separated so that the measurement tire contacts and rotates on the surface of the measurement lid ,
By using a measurement lid that can actually be used as a lid for an underground structure , and a measurement tire that can actually be used as a vehicle tire and that can travel Create conditions close to actual driving,
When the measurement tire is locked from a rotating state by a braking mechanism, the lid for an underground structure has a configuration for calculating a friction coefficient based on a ground load and a friction force generated on the measurement tire measured by load cells. Coefficient of friction measurement device on the surface. The lifting mechanism has either or both of a configuration in which the table supporting the measurement lid is moved up and down with respect to the measurement tire, or the measurement tire is moved up and down with respect to the measurement lid by moving the spindle in the axial direction. The friction coefficient measuring device on the surface of the lid for an underground structure according to claim 1 or 2. The main shaft has a sleeve joint including a fixed shaft provided in the radial direction around the main shaft and a rotary shaft provided to be rotatable with respect to the fixed shaft, and the measurement tire rotates as a constituent of the sleeve joint. The friction coefficient measuring device on the surface of a lid for an underground structure according to claim 1, wherein the device is attached to a shaft and has a structure in which a braking mechanism and load cells are arranged on the fixed shaft side. In order to be able to adjust the rotation radius of the measurement tire, the rotation axis of the sleeve joint can be changed by changing the rotation axis of the sleeve joint according to the size of the measurement lid, or the rotation axis can be changed by an expansion / contraction mechanism during measurement. The friction coefficient measuring device on the surface of a cover for an underground structure according to claim 4, wherein the device has a configuration in which the radius of rotation can be changed by moving in the axial direction. 6. The underground joint according to claim 4 or 5, wherein the sleeve joint is provided in two radial directions with the main shaft as a center, a measurement tire is provided in one sleeve joint, and a counter tire for balancing the load is provided in the other sleeve joint. A friction coefficient measuring device on the surface of a structural lid. The friction coefficient measuring device on the surface of a cover for underground structures according to claim 1 or 2, further comprising a water supply device for bringing the surface of the measurement cover into a wet state. The main shaft has a base disposed substantially horizontally at its lower end, and the base has a tire set mounting portion at a predetermined radius centered on the main shaft, and the tire set is attached to the fork via the rotating shaft. The friction coefficient measuring apparatus on the surface of a lid for an underground structure according to claim 2, comprising a tire mounted structure, wherein the fork is attached to and detached from a base mounting portion. Torque detection load cells are arranged between the main shaft and the base attached to the lower end thereof, and the table supporting the measurement lid is composed of two upper and lower tables, and load detection load cells are arranged between the upper and lower tables. The friction coefficient measuring device on the surface of the lid for an underground structure according to claim 2 or 8, wherein the friction coefficient measuring device has an arranged configuration. A table on which the measurement lid is arranged almost horizontally;
A main axis arranged substantially perpendicular to the upper part of the measurement lid so as to take an arrangement substantially perpendicular to the center of the measurement lid surface,
A fixed shaft provided at the lower end of the main shaft, with an arrangement perpendicular to the axial direction of the main shaft;
A rotating shaft for attaching the measurement tire so that the fixed tire is provided in a radial direction with the main shaft as a center, and the measurement tire goes around a path set only on the surface of the measurement lid,
It is composed of an elevating mechanism for arranging the measurement lid and the measurement tire so that they can be relatively contacted and separated so that the measurement tire contacts and rotates on the surface of the measurement lid ,
By using a measurement lid that can actually be used as a lid for an underground structure , and a measurement tire that can actually be used as a vehicle tire and that can travel Create conditions close to actual driving,
When the measurement tire is locked from a rotating state by a braking mechanism, a friction coefficient measuring device having a configuration for calculating a friction coefficient based on a ground load and a friction force generated on the measurement tire measured by a load cell is used. A way to
A method for using a friction coefficient measuring device on a surface of a lid for an underground structure, wherein the measuring time can be freely controlled by rotating the main shaft while the measuring tire is locked. An apparatus for measuring a coefficient of friction of a lid surface for an underground structure against a vehicle tire,
A table on which the measurement lid is arranged almost horizontally;
A main axis arranged substantially perpendicular to the upper part of the measurement lid so as to take an arrangement substantially perpendicular to the center of the measurement lid surface,
A base provided at the lower end of the main shaft with an arrangement perpendicular to the axial direction of the main shaft;
A rotating shaft for mounting the measurement tire so that the measurement tire circulates on a path set only on the surface of the measurement lid, provided in the radial direction around the main axis on the base ,
It is composed of an elevating mechanism for arranging the measurement lid and the measurement tire so that they can be relatively contacted and separated so that the measurement tire contacts and rotates on the surface of the measurement lid ,
By using a measurement lid that can actually be used as a lid for an underground structure , and a measurement tire that can actually be used as a vehicle tire and that can travel Create conditions close to actual driving,
When the measurement tire is locked from a rotating state by a braking mechanism, a friction coefficient measuring device having a configuration for calculating a friction coefficient based on a ground load and a friction force generated on the measurement tire measured by a load cell is used. A way to
A method for using a friction coefficient measuring device on a surface of a lid for an underground structure, wherein the measuring time can be freely controlled by rotating the main shaft while the measuring tire is locked.

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