Surveying instrument

The invention provides a surveying instrument, in which an output shaft of an ultrasonic motor is attachably and detachably connected by a bolt to a lower end of a horizontal shaft of a frame unit supported rotatably in a horizontal direction, a rotating plate is fixed to the output shaft, a vibration generating component is formed on an outer circumferential portion of the rotating plate, a stator in close contact with the vibration generating component via a predetermined friction torque T1 is rotatably provided on the output shaft, the stator is restricted on a rotation by a whirl-stop unit, ultrasonic vibration is generated in the vibration generating component and the output shaft is rotated.

BACKGROUND OF THE INVENTION

The present invention relates to a surveying instrument including a horizontal rotation driving unit with high accuracy and a simple structure.

A surveying instrument, e.g., a total station has a telescope unit for sighting a measuring point. The telescope unit is supported by a frame unit rotatably in a vertical direction, and further, the frame unit is supported rotatably in a horizontal direction by a base unit. Further, the total station includes a motor for rotating the telescope unit and a motor for rotating the frame unit.

Conventionally, a used motor is an electric motor. An output shaft of the electric motor and a rotation shaft of a rotation unit are connected via a first gear provided on the output shaft and a second gear provided on the rotation shaft and meshed with the first gear. Thereby, a mechanism is configured so that a rotating force of the electric motor is transmitted to the rotation unit via the first gear and the second gear. Further, there is a backlash in meshing between the first gear and the second gear. Since the backlash affects a rotational accuracy and a rotation positioning accuracy, the backlash needs to be made as small as possible. Particularly in a surveying instrument, an accuracy of a rotation angle is required by a unit of seconds. Thus, a highly accurate gear is needed, and further, high assembling accuracy is also required. For this reason, a manufacturing cost is high. Further, the backlash becomes large due to an abrasion of the gear or the like, and the accuracy is lowered over time.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a surveying instrument, without an error caused by a backlash or the like and including a horizontal rotation driving unit with high accuracy and a simple structure.

To attain the object as described above, in a surveying instrument according to the present invention, an output shaft of an ultrasonic motor is attachably and detachably connected by a bolt to a lower end of a horizontal shaft of a frame unit supported rotatably in a horizontal direction, a rotating plate is fixed to the output shaft, a vibration generating component is formed on an outer circumferential portion of the rotating plate, a stator in close contact with the vibration generating component via a predetermined friction torque T1is rotatably provided on the output shaft, the stator is restricted on a rotation by a whirl-stop unit, ultrasonic vibration is generated in the vibration generating component and the output shaft is rotated.

Further, in the surveying instrument according to the present invention, the stator has an intermediate fixed disk, a fixed disk and a friction sheet interposed between the intermediate fixed disk and the fixed disk, and a friction torque T2generated between the intermediate fixed disk and the fixed disk is set smaller than the friction torque T1.

Further, in the surveying instrument according to the present invention, a connection flange is provided on a lower end of the horizontal shaft, an output flange is provided on an upper end of the output shaft, the output flange is fixed to the connection flange by the bolt inserted from below, and through holes for bolt insertion are drilled in the stator and the rotating plate.

Further, in the surveying instrument according to the present invention, holes for cable insertion are formed at a central portion of the horizontal shaft and the output shaft, a slip ring is provided on a lower end of the output shaft, a first connector and a second connector are attachably and detachably provided on the slip ring, a first cable for supplying power to the vibration generating component is connected to the first connector, a second cable connected to a power supply unit incorporated in the frame unit is connected to the second connector, and power is supplied to the vibration generating component via the second cable, the second connector, the first connector and the first cable.

Furthermore, in the surveying instrument according to the present invention, the whirl-stop unit has a joint holder provided on a fixed side and a connection element provided on the stator, the joint holder has a ball holder for pressing a metal ball by a compression spring in a circumferential direction to the connection element and a connection pin holding the connection element by the ball holder and provided spanning over the joint holder and capable of tilting and wherein the whirl-stop unit restricts a displacement of the connection element in a rotating direction and absorbs a displacement in a radial direction between the joint holder and the connection element by tilting of the connection pin.

According to the present invention, in the surveying instrument, an output shaft of an ultrasonic motor is attachably and detachably connected by a bolt to a lower end of a horizontal shaft of a frame unit supported rotatably in a horizontal direction, a rotating plate is fixed to the output shaft, a vibration generating component is formed on an outer circumferential portion of the rotating plate, a stator in close contact with the vibration generating component via a predetermined friction torque T1is rotatably provided on the output shaft, the stator is restricted on a rotation by a whirl-stop unit, ultrasonic vibration is generated in the vibration generating component and the output shaft is rotated. As a result, the horizontal shaft and the output shaft are directly connected, there is not an error caused by a backlash or the like, an accuracy is improved, the ultrasonic motor can be assembled and separated by connection-detachment between the horizontal shaft and the output shaft, and disassembling/assembling performances and maintainability of the surveying instrument are improved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A description will be given below on an embodiment of the present invention by referring to the attached drawings.

FIG. 1is an entire view showing a surveying instrument1according to the present embodiment and inFIG. 1, reference numeral2denotes a leveling unit, and reference numeral3denotes a surveying instrument main body.

The surveying instrument main body3is installed on the leveling unit2, and the surveying instrument main body3is configured to be leveled to a horizontal state by the leveling unit2.

The surveying instrument main body3has a frame unit4, a horizontal rotation driving unit5and a telescope unit6. The horizontal rotation driving unit5is located on a lower end portion of the frame unit4and is mounted on the leveling unit2and supports the frame unit4capable of horizontal rotation.

On the frame unit4, the telescope unit6is provided rotatably around a horizontal axis7as the center. The telescope unit6incorporates a distance measuring unit (not shown), and the distance measuring unit projects a modulated laser beam or a pulsed light as a distance measuring light toward an object to be measured (not shown), receives a reflected distance measuring light from the object to be measured and performs a distance measurement.

Further, a horizontal rotation angle of the frame unit4and a vertical rotation angle of the telescope unit6are detected by a horizontal angle encoder (not shown) and a vertical angle encoder (not shown), respectively.

Based on a distance measuring result, a horizontal angle as detected and a vertical angle as detected, three-dimensional data of a measuring point or an object to be measured is measured.

Next, by referring toFIG. 2andFIG. 3, a detailed description will be given on the horizontal rotation driving unit5.

A motor casing11has a rigidity and strength as required and is liquid-tightly constituted by an upper case12and a lower case13. Inside the motor casing11, a horizontal motor (an ultrasonic motor)14by ultrasonic wave driving is accommodated. The lower case13is mounted on a base unit10of the leveling unit2in a spigot-joint method. Here, the motor casing11functions as a case for accommodating the horizontal motor14and also functions as a structural member for supporting the frame unit4.

A bearing block15extending upward is provided on an upper surface of the upper case12, and a horizontal shaft17penetrating up and down the bearing block15is rotatably provided. On an upper end of the horizontal shaft17, a flange18is formed, and on the flange18, a frame8of the frame unit4is fixed by a bolt9.

Between the flange18and an upper end of the bearing block15, a thrust bearing16is provided, and by means of the thrust bearing16, a vertical load of the surveying instrument main body3is supported.

On a lower end of the horizontal shaft17, a ring19is screwed up. The ring19is fixed to the horizontal shaft17so as to be rotated integrally with the horizontal shaft17.

On the ring19, a connection flange21is fixed from below by a bolt20. Further, on the connection flange21, the horizontal motor14is fixed by a bolt23. Further, the horizontal motor14can be removed from the connection flange21(that is, the horizontal shaft17) by removing the bolt23.

By referring toFIG. 3, a further description will be given on the horizontal motor14.

On an upper end of an output shaft41of the horizontal motor14, an output flange22is formed. A peripheral edge portion22aof the output flange22is thick, and the output flange22has a shape in which a recessed portion is formed at a center part. Further, at a position as required of the peripheral edge portion22a,a hole penetrating in a radial direction or a groove is formed (in the figure, a hole22bis indicated). On a lower surface of the output flange22, a rotating plate24is fixed. A diameter of the rotating plate24is larger than the output flange22, and on an outer circumferential portion of the rotating plate24extending from the output flange22, a vibration generating component25with a ring shape is provided.

On a lower surface of the vibration generating component25, comb teeth25aare formed over a total circumference. On an upper surface of the vibration generating component25, a piezoelectric ceramic (a piezoelectric element)26with a thin-plate ring shape is fixed in close contact concentrically with the rotating plate24.

On a lower side of the rotating plate24, an intermediate fixed disk27is provided. The intermediate fixed disk27is rotatably fitted with the output shaft41and the intermediate fixed disk27is capable of displacement in an axial direction. On an outer circumferential portion of the intermediate fixed disk27, a ring-shaped rib27ais formed, and the rib27ais in close contact with an lower surface of the vibration generating component25via a first friction sheet28.

A fixed disk32is rotatably fitted with the output shaft41via a bearing31and further, the fixed disk32is capable of displacement in an axial direction. Between the fixed disk32and the intermediate fixed disk27, a second friction sheet33is interposed.

On the lower end portion of the output shaft41, a fixing nut34is screwed up, and between the fixing nut34and the bearing31, a compression spring35is provided. The compression spring35is provided in a compressed state so as to act a required pressing force between the vibration generating component25and the rib27aand between the intermediate fixed disk27and the fixed disk32.

Further, by the pressing force applied by the compression spring35, a relationship between a friction torque T1, which is generated between the vibration generating component25and the intermediate fixed disk27, and a friction torque T2, which is generated between the intermediate fixed disk27and the fixed disk32, is T1>T2. Further, T2is larger than a driving torque required for the horizontal motor14during a normal operation.

On the lower end of the output shaft41, a slip ring36is mounted. A first connector38a(seeFIG. 2) is attachable to and detachable from the slip ring36, and a second connector38b(seeFIG. 2) is attachable to and detachable from the slip ring36. The first connector38aand the second connector38bcan be connected/disconnected via the slip ring36. It is to be noted that the first connector38aand the second connector38bmay be capable of connecting or disconnecting directly.

To the first connector38a,a first cable39ais connected, and the first cable39ais connected to the piezoelectric ceramic26. Further, to the second connector38b,a second cable39bis connected, and the second cable39bis connected to a power supply unit (not shown) included inside the frame unit4.

The first cable39ais wired to reach from the piezoelectric ceramic26through the hole22band a hole formed at a center of the output shaft41to the first connector38a.The second cable39bis wired to reach from the second connector38bthrough a hole formed at a center of the output shaft41and a hole formed at a center of the horizontal shaft17to the power supply unit.

By supplying an electric power from the power supply unit to the vibration generating component25, the comb teeth25aare ultrasonically vibrated, and it is so arranged that a relative rotation is generated between the intermediate fixed disk27and the vibration generating component25.

Further, between the intermediate fixed disk27and the fixed disk32, a friction force acts, and the intermediate fixed disk27and the fixed disk32are rotatable with respect to the output shaft41. Therefore, the intermediate fixed disk27and the fixed disk32are rotated integrally. Further, as described later, between the fixed disk32and the lower case13(that is to say, a fixing member), a whirl-stop unit45is provided, and a rotation of the fixed disk32is restricted.

Therefore, the intermediate fixed disk27and the fixed disk32function as a stator, and the output shaft41(that is, the output flange22) functions as a rotor. By supplying power to the piezoelectric ceramic26and by controlling power supplying, the output flange22is rotated in a required direction at a required rotation speed.

Next, a description will be given on mounting of the horizontal motor14to the bolt23.

As described above, the horizontal motor14, in which the rotating plate24, the intermediate fixed disk27, the fixed disk32or the like are concentrically assembled to the output shaft41, is constituted as a unit.

The output flange22has a function as an output end of the horizontal motor14and also has a function as a joint for connecting the horizontal motor14to the horizontal shaft17.

In the output flange22, a bolt hole for the bolt23is drilled. Further, a through hole42ais drilled in the fixed disk32, a through hole42bis drilled in the intermediate fixed disk27and further a through hole42cis drilled in the rotating plate24, respectively. The through hole42a, the through hole42b,and the through hole42ccan be aligned on the same axis, and in a state aligned on the same axis, the bolt23can be inserted into a bolt hole from below through the through hole42a,the through hole42b,and the through hole42cand further, the bolt23can be screwed to the connection flange21.

That is to say, by the bolt23, the horizontal motor14can be connected to the connection flange21(that is to say, the horizontal shaft17).

The slip ring36is mounted on the output shaft41after the horizontal motor14is connected to the horizontal shaft17. Further, the first connector38aof the first cable39ais connected to the slip ring36and the second cable39bis connected to the second connector38b.

Therefore, after individually assembling only the horizontal motor14and adjusting, the horizontal motor14can be assembled into the horizontal shaft17, and the assembling and adjusting of the horizontal motor14can be carried out in parallel with assembling and adjusting of the surveying instrument main body3. Further, it is possible to remove the horizontal motor14and to adjust individually.

On the slip ring36, ring-shaped contacts40are formed concentrically and multiply, and to the contact40, sliding contacts37are connected. To the sliding contacts37, a cable37ais connected, and it is so arranged that a communication with an outside and power supplying from the outside can be carried out via the sliding contact37.

Next, by referring toFIG. 4, a description will be given on the whir stop unit45.

As described above, the horizontal motor14is mounted on the lower end of the horizontal shaft17, and a relative rotation is possible between the output flange22and the intermediate fixed disk27, the fixed disk32. However, in order to obtain a rotating force from the output shaft41, the intermediate fixed disk27and the fixed disk32needs to be fixed.

The whirl-stop unit45connects the fixed disk32and the lower case13to each other and restricts a rotation of the fixed disk32.

The whirl-stop unit45has a joint holder47and the joint holder47is mounted on the lower case13by a bolt48. The joint holder47is manufactured by machining, die-casting or the like and has a rigidity and a strength as required.

Further, on the joint holder47, a recessed portion49extending in a tangential direction of the lower case13(a tangential direction of a circle around an axis of the output shaft41as the center) is formed. The recessed portion49is surrounded by a L-shaped brim portion50positioned on an outer circumferential side and a thick base portion51positioned on a base side (lower side inFIG. 4) of the recessed portion49in three sides, and a center side is open.

To the recessed portion49, a ball holder52having an L-shaped outer shape is fixed by a bolt53at one spot. Further, the ball holder52is in contact with the brim portion50. Further, the ball holder52is capable of positional adjustment by a pushing screw5.

In the ball holder52, a cylindrical hole55with an axis in a tangential direction is drilled, and in the cylindrical hole55, a compression spring56is accommodated in a compressed state. Further, at a forward end of the compression spring56, a metal bail or preferably a steel ball57is provided.

In the base portion51, a pin accommodating hole58is drilled so as to be concentric with the cylindrical hole55, and a hole bottom of the pin accommodating hole58is made to be a circular cone. In the pin accommodating hole58, a connection pin65is inserted. Both ends of the connection pin65are formed a spherical shape.

A diameter of the pin accommodating hole58is larger than a diameter of the connection pin65, and the connection pin65is capable of tilting around a base end as the center in a state where the base end is fitted with the circular cone.

To the fixed disk32, a connection plate61is fixed by a bolt62. The connection plate61is manufactured by machining, die-casting or the like and has a rigidity and a strength as required.

In the connection plate61, a connection element61ais provided to protrude at a forward end. The connection element61ais inserted between the ball holder52and the base portion51.

Further, in the connection element61a,a pin receiving hole63is drilled so as to be concentric with the pin accommodating hole58. A hole bottom of the pin receiving hole63is made to be a circular cone.

In the pin receiving hole63, a forward end portion of the connection pin65is inserted, and the connection pin65is provided by spanning between the pin accommodating hole58and the pin receiving hole63.

With a surface on a side opposite to the pin receiving hole63of the connection element61a,the steel ball57comes into contact.

On a contact surface of the steel ball57, a pressing force by the compression spring56acts in a tangential direction (a circumferential direction), and a pressing reaction force from the connection pin65acts on a hole bottom of the pin receiving hole63. Further, by a reaction of the compression spring56, the ball holder52is given a rotating force in a counterclockwise direction (inFIG. 4), and the ball holder52is brought into close contact with the brim portion50and an attitude is fixed.

Therefore, a position in a circumferential direction of the connection plate61is determined by the base portion51via the connection pin65. Further, in a case where the connection plate61is displaced in a radial direction with respect to the joint holder47, the steel ball57slides against the connection plate61, and the connection pin65tilts, and a displacement of the connection plate61is absorbed.

Thus, the whirl-stop unit45restricts a rotation of the fixed disk32and moreover, if the output shaft41is eccentric with respect to the horizontal shaft17, a rotational deviation caused by an eccentricity is absorbed.

A description will be given on a horizontal rotation driving by the horizontal motor14.

When a voltage is applied to the piezoelectric ceramic26, the comb teeth25aare ultrasonically vibrated and a relative rotation generates between the intermediate fixed disk27and the rotating plate24.

Since the intermediate fixed disk27is fixed to the lower case13via the fixed disk32and the whirl-stop unit45, the output shaft41, that is, the output flange22is rotated.

A rotating force of the output shaft41is transmitted to the horizontal shaft17via the output flange22, and the frame unit4is horizontally rotated.

Even in a case where an error is generated by mounting of the output flange22to the connection flange21and the output shaft41becomes eccentric with respect to the horizontal shaft17, as described above, the eccentricity is absorbed by the whirl-stop unit45, and the eccentricity does not influence a rotation of the horizontal shaft17. Further, even if the horizontal motor14itself has a run out, the error of the horizontal motor14itself does not influence a rotational accuracy of the horizontal shaft17.

That is to say, according to the present embodiment, there is no need to carry out with high accuracy a mounting of the horizontal motor14to the horizontal shaft17.

Further, since the horizontal motor14and the horizontal shaft17are directly connected to each other, a backlash or the like is not interposed in a power transmission path, power can be transmitted with high accuracy and a deterioration of accuracy over time does not occur.

Next, a description will be given on a case where an excessive load is generated in the output shaft41during driving of the horizontal motor14, e.g., a case where the surveying instrument main body3interferes with a foreign object and rotation of the surveying instrument main body3is restricted. Since a friction torque12between the intermediate fixed disk27and the fixed disk32is set smaller than a friction torque T1between the rotating plate24and the intermediate fixed disk27, a slip is generated between the intermediate fixed disk27and the fixed disk32, and only the intermediate fixed disk27is rotated. That is to say, the horizontal motor14itself has a safety function against an overload.

Therefore, such a situation that an excessive load is applied to the horizontal motor14and the horizontal motor14is damaged is prevented. It is to be noted that the fact that the surveying instrument main body3is restricted is detected by the horizontal angle encoder (not shown), and driving of the horizontal motor14is stopped.

Further, even if the surveying instrument1is in a halt state, a stop state of the surveying instrument main body3is maintained by a friction torque of the horizontal motor14, and by giving a lager rotating force than the friction torque T2between the intermediate fixed disk27and the fixed disk32, the frame unit4can be rotated in a required direction.

Next, in a case where maintenance with respect to the horizontal motor14is carried out, after the lower case13is removed from the upper case12, the second connector38band the first connector38aare removed and the slip ring36is removed.

The through hole42a,the through hole42band the through hole42care aligned on the same axis, and the bolt23is removed from the connection flange21.

Since the horizontal motor14is fixed to the connection flange21only by the bolt23, the horizontal motor14can be removed integrally. Therefore, a removal and an assembling are easy and a maintainability is excellent.

It is to be noted that, in a case where there is a space above the upper case12, a hole or a window for bolt insertion is formed in the upper case12, and the connection flange21and the output flange22may be fixed from above by a bolt. Further, in the present embodiment, the connection flange21and the horizontal shaft17are provided separately but the connection flange21may be formed integrally on a lower end of the horizontal shaft17.

Further, in the embodiment as described above, the horizontal motor14is provided on a lower end of a rotation shaft (the horizontal shaft17), but it is needless to say that the horizontal motor14can be similarly provided on an upper end.