Rotation detector detecting rotation of rotating machine and system provided with rotation detector

A rotation detector which can improve the manufacturing efficiency of a rotating machine. The rotation detector is provided with a connecting part which is fastened in contact with a rotating part of the power part, an output shaft which extends from the connecting part to one side in the axial direction, and a moving part which is comprised of a connecting part and output shaft and, further, has a detected region which is formed at a maximum outer circumferential surface of the connecting part and output shaft, and a fixed part which is fastened to the connecting part at the outside in the radial direction and which detects a change in magnetic field which is generated along with rotation of the detected region.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a rotation detector which detects rotation of a rotating machine and a system which is provided with a rotation detector.

2. Description of the Related Art

In the field of servo motors and other rotating machines, it is known to install a rotation detector for obtaining information relating to rotation such as the rotational speed, rotational angle, etc., of the rotating machine (for example, see Japanese Patent Publication No. 2006-10436A). This rotation detector is provided with a moving part which rotates together with an output shaft of the rotating machine and a fixed part which is fastened at the outside of the moving part in the radial direction and which detects a change of a magnetic field which occurs along with rotation of the moving part.

In a conventional rotating machine, the moving part of the rotation detector has been made as a member independent from the rotating part of the rotating machine. Therefore, to secure the performance of the rotation detector, when assembling the rotating machine, precisely positioning the moving part of the rotation detector with respect to the rotating part of the electric motor is necessary. Due to this, it is complicated and improvement of the manufacturing efficiency becomes difficult.

Specifically, the detected part of a rotation detector for which high precision positioning is demanded must be produced separately as an independent ring member separate from the rotation output member which is fastened to the rotating part of the rotating machine. This ring member is fit over the rotation output member when assembling of the rotating machine.

When assembling, the rotation output member which is fastened to the rotating part of the rotating machine is fastened to the rotating part so as to become concentric with the rotating part of the rotating machine, then the ring member at which the detected part is provided is fastened to the rotation output member so as to become concentric with the axis of rotation. Therefore, two steps of precise centering are necessary. Due to this, the assembly process of the rotating machine is complicated and the manufacturing efficiency of the rotating machine is reduced.

The present invention, in consideration of the above problem, has as its object the provision of a rotation detector which can improve the manufacturing efficiency. Further, the present invention has as another object the provision of a system which is provided with a rotating machine and a rotation detector which can improve the manufacturing efficiency.

SUMMARY OF THE INVENTION

As one aspect of the present invention, a rotation detector for detecting rotation of a rotating machine, comprising a moving part including a connecting part fastened in contact with a rotating part of the rotating machine; an output shaft extending from the connecting part to one side in the axial direction; and a first detected part formed at a first outer circumferential surface which has a maximum outside diameter in the connecting part and the output shaft; and a fixed part fastened separated from the first outer circumferential surface at the outside in the radial direction, and detecting a change in a magnetic field which occurs with rotation of the first detected part is provided.

Further, an end face of the output shaft at the one side in the axial direction and an end face at the connecting part at the other side in the axial direction positioned opposite to that end face may be provided with a hole or a projection which is concentric with the center of the output shaft and first outer circumferential surface.

The rotation detector may further comprise a ring-shaped second moving part which is made as a separate member from the moving part, and which is fastened to the moving part. The second moving part may have a second detected part at a second outer circumferential surface of the second moving part. In this case, the first detected part may include a plurality of recesses or projections which are formed at the first outer circumferential surface so as to be arranged at equal intervals in the circumferential direction, while the second detected part may include a single recess or projection which is formed at the second outer circumferential surface. The fixed part detects a change in the magnetic field which occurs with rotation of the first detected part and second detected part.

Further, as a second aspect, the moving part may have a second detected part which is integrally formed with the first detected part so as to adjoin it in the axial direction. In this case, the first detected part may include a plurality of recesses or projections which are formed at the first outer circumferential surface so as to be arranged at equal intervals in the circumferential direction, while the second detected part may include a single recess or projection which is formed at the first outer circumferential surface. The fixed part detects a change in the magnetic field which occurs with rotation of the first detected part and second detected part. Further, a groove may be formed between the first detected part and the second detected part so as to extend in the circumferential direction over the entire first outer circumferential surface.

DETAILED DESCRIPTION

Below, embodiments of the present invention will be explained in detail based on the drawings. First, referring toFIG. 1, the configuration of a system10according to one embodiment of the present invention will be explained. Note that, in the following explanation, the rotation axis O1of the electric motor11is the axial direction, the left direction inFIG. 1is the front in the axial direction, and the right direction inFIG. 1is the back in the axial direction.

The system10is provided with an electric motor11which is set inside of a housing12and a rotation detector100for detecting rotation of the electric motor11. The electric motor11is a servo motor or other such motor which is electrically controlled and is fastened in a space13which is defined at the inside of the housing12.

The electric motor11has a power output part14which generates rotational force and a rotating part15which outputs rotation which is generated by the power output part14. The power output part14includes a stator (not shown), and a rotor (not shown) disposed to be able to rotate. A coil is wound around the surface of the stator. Further, the rotor includes magnets.

If current flows to this coil from a power source which is set at the outside (not shown), the stator causes a rotating magnetic field to be formed around the axis O1. The rotor receives electromagnetic force in the circumferential direction due to the rotating magnetic field which is generated by the stator. As a result, the rotor rotates around the shaft.

The rotating part15is mechanically coupled to the rotor of the power output part14and rotates together with the rotor. The rotating part15is attached to the power output part14so as to extend to the outside of the power output part14and to be able to rotate.

The rotation detector100has a moving part101which is fastened to the rotating part15of the electric motor11; and the fixed part102which is fastened separated from the moving part101to the outside in the radial direction. The moving part101rotates together with the rotating part15.

Next, referring toFIG. 2andFIG. 3, the configuration of the moving part101according to the present embodiment will be explained. The moving part101is made of e.g., iron or another ferromagnetic material. The moving part101has a columnar-shaped connecting part103which is fastened in contact with the rotating part15of the electric motor11shown inFIG. 1; and a columnar-shaped output shaft105which extends from an end face104of the connecting part103at the front in the axial direction toward the front in the axial direction. The connecting part103and output shaft105are arranged concentrically with each other and have a common center axis O2.

Note that, in the assembled state as shown inFIG. 1, the moving part101is fastened to the rotating part15of the electric motor11so that the center axis O2of the moving part101and the rotation axis O1of the electric motor11match each other. The output shaft105has a diameter smaller than the connecting part103and a length in the axial direction longer than the connecting part103. The output shaft105is a member which outputs the rotational force generated by the power output part14to an external equipment (for example, a robot arm) which is connected to the electric motor11.

At the outer circumferential surface of the part which has the maximum outside diameter in the moving part101, a detected region107is formed. In the present embodiment, the part having the maximum outside diameter in the moving part101is a stepped part112provided at the connecting part103. The detected region107is formed on the outer circumferential surface of this stepped part112. The detected region107includes a second detected part108formed adjacent to the end face104of the connecting part103; and a first detected part109formed adjacent to the second detected part108at the back in the axial direction of the second detected part108.

At the first detected part109, a plurality of recesses111′ which are inwardly recessed from the outer circumferential surface of the stepped part112of the connecting part103and projections111which have outside diameters the same as the stepped part112are formed so as to be alternately arranged. Each of the projections111of the first detected part109has the same width in the circumferential direction. The projections111are formed so as to be arranged at substantially equal intervals in the circumferential direction over the entire stepped part112of the connecting part103. On the other hand, at the second detected part108, only a single projection110which has an outside diameter the same as the stepped part112of the connecting part103is formed.

Note that, in the present embodiment, the projection110of the second detected part108is formed so as to continuously extend from one of the projections111of the first detected part109. In other words, the projection110and the corresponding single projection111are formed by a single projection which extends in the axial direction. The center of the stepped part112is arranged to be concentric with the center axis O2. In other words, the center of curvature of each of the outer surface of the projection110matches with the center axis O2.

The dimensions of the projections110and111which constitute the detected region107, such as the width in the axial direction, height in the radial direction, and radius of curvature of the stepped part112, are strictly controlled with predetermined tolerances. In particular, the projections111of the first detected part109are formed for example by using a CNC machine tool to cut the stepped part112of the connecting part103by a method controlled to a high precision while strictly controlling them in dimensions.

A total of four mounting holes113are formed on the end face104of the connecting part103so as to be arranged at substantially equal intervals in the circumferential direction. The moving part101is fastened to the rotating part15of the electric motor11via four bolts which are passed through the mounting holes113and screwed into the rotating part15of the electric motor11.

Referring again toFIG. 1, the fixed part102is supported by the housing12so as to be separated from the detected region107provided at the moving part101by a predetermined distance (for example, 0.1 mm) to the outside in the radial direction. The fixed part102has magnets (not shown) which are arranged at the outside in the radial direction of the detected region107and magnetoresistance elements (not shown) which are arranged between the detected region107and the magnets.

A magnetoresistance element is a resistance element which changes in resistance value in accordance with the intensity of the magnetic field in which the element is placed. A bias voltage is applied between the two terminals of this magnetoresistance element. The voltage of the magnetoresistance element is detected as the output voltage. The fixed part102detects the change in the output voltage of the magnetoresistance element at this time to thereby detect the change in magnetic field which is generated along with the rotation of the detected region107.

Next, referring toFIG. 1toFIG. 3, the operation of the rotation detector100according to the present embodiment will be more specifically explained. When the power output part14of the electric motor11drives the rotating part15to rotate, the moving part101also rotates together with the rotating part15. Then, the detected region107formed at the connecting part103also rotates relative to the fixed part102.

With rotation of the detected region107, the projection110of the second detected part108passes once a position corresponding to a magnetoresistance element for second detected part108disposed in the fixed part102, during the moving part101rotates by one turn. When the projection110of the second detected part108passes the position corresponding to the magnetoresistance element for second detected part108, the magnetic field near the magnetoresistance element for second detected part108is stronger.

The fixed part102detects the change in this magnetic field as a change of the output voltage of the magnetoresistance element and outputs it as an electrical signal which is generated each time the electric motor11turns once. The rotation detector100outputs the electrical signal as an origin signal (single turn signal) for determining a position serving as the reference for the rotational angle (origin position).

In the same way, with rotation of the detected region107, the projections111of the first detected part109successively pass a position corresponding to a magnetoresistance element for first detected part109built in the fixed part102. The fixed part102detects the changes of the magnetic field near the magnetoresistance element for first detected part109which were generated due to passing the projections111as changes of the output voltage of the magnetoresistance element. Then, the fixed part102outputs an electrical signal generated exactly the number of times corresponding to the number of projections111with each turn of the electric motor11.

The rotation detector100outputs a signal which is obtained by further electrically processing the above electrical signal as an angle signal for detecting the rotational angle of the electric motor11. Based on the origin signal and angle signal thus obtained, information relating to rotation, such as the rotational angle, rotational position, rotational speed, etc., of the electric motor11is obtained.

According to the present embodiment which is provided with the above configuration, it is possible to improve the manufacturing efficiency of the system10. This will be explained below. Generally, for the rotation detector100, it is necessary to precisely position the detected region107for rotation detection with respect to the fixed part102, in order to precisely detect rotation of the electric motor11.

Specifically, the axial direction positions of the first detected part109and second detected part108of the detected region107have to substantially match the axial direction positions of the magnetoresistance element for first detected part109and magnetoresistance element for second detected part108of the fixed part102. The tolerance in this case is, for example, about 0.5 mm. Further, the detected region107and the fixed part102have to be arranged to face each other with a predetermined interval in the radial direction. This interval is set to 0.1 mm. The tolerance of this interval is about 0.02 mm.

As explained above, in the conventional art, the detected part of a rotation detector for which high precision positioning was demanded was produced as an independent ring member separate from the rotation output member fastened to the rotating part of the rotating machine, and then ring member was fit over the rotation output member in the assembly process of the rotating machine. As a result, the process of assembly of a system which is provided with the rotating machine and the rotation detector becomes complicated. This leads to a drop in the manufacturing efficiency of the system.

On the other hand, in the present embodiment, the moving part101which constitutes the rotation detector100has an output shaft105and a detected region107formed at the connecting part103and is directly fastened to the rotating part15of the electric motor11. In other words, the moving part101according to the present embodiment has both the function of detecting rotation of the electric motor11and the function of outputting rotational force of the electric motor11to an external equipment.

According to this configuration, it is possible to directly form a detected region107on the rotation output member (i.e., the moving part101) which is fastened to the rotating part15of the power output part14by cutting the stepped part112of the connecting part103by a precisely controlled method with using e.g., a CNC machine tool.

Due to this, it is possible to eliminate the centering work necessary for precisely positioning the detected region107which had previously been necessary. As a result, it is possible to simplify the work, so it is possible to improve the manufacturing efficiency of the system10. Further, it is easier to raise the concentricity compared with centering of the detected part of a separate member.

Further, in the past, the ring member at which the detected part was provided had to be fastened by bolting etc. to the rotation output member which was fastened to the rotating part of the electric motor. However, according to this embodiment, such bolting work becomes unnecessary and the number of parts can be cut. Further, there is also no rattling between the rotational output member and the detected part due to looseness of the bolts, so the reliability can be improved.

Next, referring toFIG. 4, a moving part201according to another embodiment of the present invention will be explained. Note that, members similar to the above embodiment are assigned the same reference numerals and detailed explanations will be omitted. The moving part201is provided with a connecting part103and a columnar shape output shaft205which extends from the end face104of the connecting part103at the front in the axial direction toward the front in the axial direction.

The output shaft205has a relatively large outside diameter and small length in the axial direction compared with the output shaft105of the embodiment which is shown inFIG. 2. In the present embodiment, a total of four mounting holes204are formed so as to be arranged at equal intervals in the circumferential direction and extend from the end face202of the output shaft205at the front in the axial direction to the end face203of the connecting part103at the back in the axial direction. The moving part201is fastened to the rotating part15of the electric motor11through four bolts which are passed through the mounting holes204and screwed into the rotating part15of the electric motor11.

Next, referring toFIGS. 5A and 5B, a moving part301according to another embodiment of the present invention will be explained. The moving part301shown inFIGS. 5A and 5Bhas generally the same configuration as the moving part101shown inFIG. 2. Specifically, the moving part301has a columnar-shaped connecting part103fastened in contact with the rotating part15of the electric motor11; and a columnar shape output shaft105extending from the end face104of the connecting part103at the front in the axial direction toward the front in the axial direction.

The moving part301has a hole303which is inwardly recessed from the end face302of the connecting part103at the back in the axial direction; and a hole305which is inwardly recessed from the end face304of the output shaft105at the front in the axial direction. These holes303and305are arranged concentrically with the center axis O2of the moving part301. In other words, the centers of the holes303and305match the center axis O2.

These holes303and305are formed before the step of forming the detected region107. When forming the detected region107on the stepped part112of the connecting part103, the stepped part112of the connecting part103is cut by using these holes303and305as reference. Due to this, it is possible to raise the concentricity with respect to the center axis O2of the detected region107while forming the detected region107with a high precision.

Note that, the moving part301may have, instead of the above holes303and305, a through hole which extends from the end face302of the connecting part103to the end face304of the output shaft105. Further, the moving part301may have a projection which sticks out from the end face302of the connecting part103and a projection which sticks out from the end face304of the output shaft105.

Such through holes or projections, like the above holes303and305, are arranged concentrically with the center axis O2of the moving part301. In this case, these through holes or projections may be used as references for raising the concentricity with respect to the center axis O2of the detected region107in the step of forming the detected region107.

Next, referring toFIG. 6andFIG. 7, a moving part assembly400according to one embodiment of the present invention will be explained. The moving part assembly400is an element which constitutes a rotation detector together with the above fixed part102and which is fastened to the rotating part15of the electric motor11. The moving part assembly400comprises a first moving part401and a second moving part402.

The first moving part401is made of e.g. iron or another such ferromagnetic material. The first moving part401includes a columnar-shaped connecting part403fastened in contact with the rotating part15of the electric motor11; a columnar-shaped boss part405extending from the end face404of the connecting part403at the front in the axial direction toward the front in the axial direction; and a columnar-shaped output shaft407extending from the end face406of the boss part405at the front in the axial direction toward the front in the axial direction.

The boss part405has an outside diameter smaller than the connecting part403and a length in the axial direction smaller than the connecting part403. Further, the output shaft407has an outside diameter which is smaller than the boss part405and a length in the axial direction which is longer than the boss part405. The output shaft407is a member which outputs the rotational force generated by the power output part14to an external equipment (for example, robot arm) which is connected to the electric motor11.

The connecting part403, the boss part405, and the output shaft407are arranged concentrically with each other and have a common center axis O3. The part having the maximum outside diameter in the first moving part401is the stepped part408which is provided at the connecting part403. On the outer circumferential surface of the stepped part408, the first detected part409is formed. Specifically, the first detected part409includes recesses411′ which are recessed inward from the outer circumferential surface of the stepped part408of the connecting part403; and a plurality of projections411which have outside diameters same as the stepped part408.

Each of the projections411has a same width in the circumferential direction. The projections411are formed so as to be arranged at substantially equal intervals in the circumferential direction over the entire circumference of the stepped part408of the connecting part403. Further, a total of four screw holes410are formed at the end face404of the connecting part403.

A total of four mounting holes113are formed at the boss part405so as to be arranged at equal intervals in the circumferential direction. The first moving part401is fastened to the rotating part15of the electric motor11via four bolts which are passed through the mounting holes113and screwed into the rotating part15of the electric motor11.

On the other hand, the second moving part402is an annular shape ring member having a common center axis O3with the first moving part401and which is made of iron or another such ferromagnetic material similar as the first moving part401. The second moving part402has a second detected part413at its outer circumferential surface412. Specifically, the second detected part413includes a single recess416which is recessed inward from the outer circumferential surface412. Further, the second moving part402has a total of four through holes (not shown).

The second moving part402is fastened to the first moving part401via four bolts41which are passed through the through holes and are screwed into the screw holes410of the connecting part403. At this time, the end face417of the second moving part402at the back side in the axial direction and the end face404of the connecting part403at the front side in the axial direction are in surface contact, and the inner circumferential surface415of the second moving part402and the outer circumferential surface419of the boss part405face each other with a predetermined interval.

When fastening the moving part assembly400to the rotating part15of the electric motor11, the moving part assembly400is fastened to the rotating part15so that the center axis O3of the moving part assembly400and the axis O1of the electric motor11match each other.

The first detected part409formed at the first moving part401is used for acquiring the above angle signal. On the other hand, the second detected part413formed at the second moving part402is used for obtaining the above origin signal.

As explained above, the second detected part413includes a single recess416. Therefore, while the electric motor11turns once, the magnetic field near the magnetoresistance element for second detected part413changes just once. The fixed part102arranged radially outside of the second detected part413outputs a corresponding electrical signal. In this way, the electrical signal generated by the recess416can also be used as the origin signal in the same way as the electrical signal generated by the projection110inFIG. 2.

In the present embodiment, the second moving part402having the second detected part413for acquiring the origin signal is made as a separate member from the first moving part401. According to this embodiment, it is possible to improve the manufacturing efficiency as a rotation detector, which will be explained below.

If N number of projections411is formed in the circumferential direction in the first detected part409, the fixed part102successively outputs N number of the electrical signals generated by the first detected part409while the electric motor11turns once.

On the other hand, the fixed part102outputs one electrical signal generated by the second detected part413while the electric motor11turns once. Thus, the electrical signals by the first detected part409are successively generated over the entire circumference of the stepped part408.

For this reason, when the center of the first detected part409does not match the rotation axis of the electric motor11(i.e., when it is off-centered), the cycle of each of the electrical signals continuously change, and as a result, detection error occurs. In order to prevent such detection error, it is necessary to precisely position the first detected part409relative to the rotation axis of the electric motor11.

On the other hand, as explained above, the electrical signal generated by the second detected part413is only generated once every turn, and therefore is not significantly influenced even though an eccentricity of the axes of the second detected part413and the electric motor11is occurred. Accordingly, the second detected part413does not have to be as precisely positioned relative to the fixed part102as with the first detected part409.

According to the present embodiment, the first detected part409for which precise positioning is demanded is directly formed at the first moving part401which is fastened to the rotating part15of the electric motor11, while the second moving part402allowed for a relatively wider tolerance is made as a separate member from the first moving part401and fastened to the first moving part401via bolts with a tolerance of loose fitting.

According to this embodiment, similar as the above embodiment, it is possible to eliminate the centering work of the first detected part409. Further, the second detected part413having a simpler shape than the first moving part401can be efficiently mass produced by a separate process from the first moving part401.

Further, in the above way, by fastening the mass produced second moving part402to the first moving part401by bolting or other such simple work, a moving part assembly400can be assembled. Due to this, the manufacturing efficiency as a rotation detector can be improved.

Next, referring toFIG. 8andFIG. 9, a moving part assembly500according to another embodiment of the present invention will be explained. The moving part assembly500comprises a first moving part401similar to the embodiment shown inFIG. 6and a second moving part502according to the present embodiment.

The second moving part502has a columnar-shaped main part503having a second detected part413; and a columnar-shaped boss part505projecting from the axially back end face504of the main part503toward the back in the axial direction. The second detected part413provided at the main part503is similar to that of the above embodiment and includes a single recess416.

The boss part505has an outside diameter smaller than the main part503and a length in the axial direction smaller than the main part503. Further, the second moving part502has a total of four through holes506. The second moving part502is fastened to the first moving part401via bolts414which are passed through these through holes506and screwed into the screw holes410(FIG. 6) which are formed in the first moving part401.

As shown inFIG. 8, in the state where the moving part assembly500is assembled, a groove507is formed between the end face404of the connecting part403at the front in the axial direction of the first moving part401and the end face504of the main part503at the back in the axial direction of the second moving part502. This groove507extends over the entire circumference of the moving part assembly500and has a length in the axial direction which corresponds to the boss part505of the second moving part502.

Due to this groove507, the first detected part409provided at the first moving part401and the second detected part413provided at the second moving part502are separated from each other by exactly a distance corresponding to the length in the axial direction of the boss part505of the second moving part502.

By separating the first detected part409and the second detected part413from each other in this way, the origin signal obtained by the recess416of the second detected part413and the angle signal obtained by the projections411of the first detected part409can be detected with a high precision as better separated individual signals.

Next, referring toFIG. 10andFIG. 11, a moving part601according to still another embodiment of the present invention will be explained. The moving part601, like in the embodiment shown inFIG. 2, comprises a connecting part103and output shaft105. The part having the maximum outside diameter in the moving part601is the stepped part612provided at the connecting part103. The detected region607is formed on the outer circumferential surface of this stepped part612.

Specifically, the detected region607includes a second detected part608formed adjacent to the end face104of the connecting part103; and a first detected part609formed at the back of the second detected part608in the axial direction. In the first detected part609, pluralities of recesses611′ which are recessed inward from the outside surface of the stepped part612and projections611which have the same outside diameter as the stepped part612are formed so as to be alternately arranged.

Each of the projections611has same width in the circumferential direction and formed so as to be arranged at substantially equal intervals over the entire circumference of the stepped part612of the connecting part103. On the other hand, in the second detected part608, only a single projection610having the same outside diameter as the stepped part612is formed.

In the present embodiment, a groove613is formed between the first detected part609and the second detected part608. This groove613has a predetermined width in the axial direction and extends in the circumferential direction over the entire circumference of the stepped part612of the connecting part103. Due to this groove613, the projections611of the first detected part609and the projection610of the second detected part608are separated from each other by exactly a distance corresponding to the width in the axial direction of the groove613.

By arranging the projection610and the projections611separated from each other in this way, the origin signal obtained by the projection610of the second detected part608and the angle signal obtained by the projections611of the first detected part609can be detected with a high precision as better separated individual signals.

Note that, in the above embodiments, the case where the connecting part and output shaft were columnar shaped was explained, but the invention is not limited to this. For example, they may also be polygonal shapes or elliptical shapes or other such shapes.

Further, in the above embodiments, the detected part was explained as including recesses or projections. However, the invention is not limited to this. So long as able to use rotation of the detected part to change the magnetic field between the magnets of the fixed part and the detected part, the detected part may also be of any type. For example, the detected part may have magnets which are arranged in the circumferential direction and may have a material which changes in magnetism in the circumferential direction.

Further, in the above embodiments, the case where the stepped part which was provided at the connecting part was the part which has the maximum outside diameter in the first moving part was explained. However, the invention is not limited thereto. The rotating shaft part may also be the part which has the maximum outside diameter in the first moving part. In this case, the first detected part may be formed at the outer circumferential surface of the rotating shaft part.

Further, in the above embodiments, an electric motor was explained as one example of a rotating machine and the case where the rotation detector according to the present invention was used for detecting the rotation of the electric motor was explained. However, the invention is not limited to this. The rotation detector according to the present invention can detect rotation of a broad range of rotating machines such as generators and heat engines which are driven to operate by combustible fuel.

As explained above, according to the present invention, by precisely cutting the outer circumferential surface of the connecting part, it becomes possible to directly form the detected part on the moving part which is fastened on the rotating part of the rotating machine. Due to this, it is possible to eliminate the centering work necessary for precisely positioning the detected part which had been required in the past. As a result, it is possible to simplify the work of assembling a rotating machine, and therefore it is possible to improve the manufacturing efficiency of a rotating machine.

Further, the moving part which forms part the rotation detector has an output shaft and a detected part, so is provided with both the function of detecting the rotation of the rotating machine and the function of outputting the rotational force of the rotating machine to an external equipment. Due to this, it is possible to reduce the power transmission error due to rattling or backlash which occurs at the time of transmission of rotational force to external equipment.

Further, in the past, the ring member at which the detected part is provided had to be fastened by bolting, etc., to the rotation output member which is fastened to the rotating part of the electric motor, but such bolting work becomes unnecessary and the number of parts can be reduced.

Above, the present invention was explained through embodiments of the present invention, but the above embodiments do not limit the invention relating to the claims. Further, all combinations of features which were explained in the embodiment are not necessarily essential for the invention. Further, the above embodiments can be changed or improved in various ways as clear to a person skilled in the art. Such changed or improved embodiments are also included in the technical scope of the present invention as clear from the claim language.