JPH07298555A - Servomotor - Google Patents

Abstract

PURPOSE:To reduce the number of parts by excluding the dual structure of an encoder frame and a cover and reducing the occupied space of a light encoder and the like in the periphery of a rotational position detector. CONSTITUTION:A printed wiring board 4 is mounted in a fully-closed condition in the outer end surface of a cylindrical body 11 in the anti-operation side end surface of a sheath 1. A module 3a is mounted inside the printed wiring board 4 so that the direction of light is directed to the axial direction. The periphery of the rotary disk 3b of a light encoder 3 is located in a groove 3s, and the rotary disk 3b is mounted at the end 2b of a shaft passing through the sheath 1 through a bushing 3c. A notch window 12 through which the module 3a can pass in the radial direction and which is opened in the outer end surface is provided in the cylindrical body 11. A detachable window cover 13 is mounted in the notch window 12, and a cable is pulled out from the window cover 13. Electronic parts and the like are mounted inside the printed wiring board 4. Since the outer surface of the printed wiring board 4 is exposed to outside air, it is easy to cool.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servomotor characterized by a rotational position detector mounting structure. Here, the rotational position detector is an optical encoder, a magnetic encoder, an inductive encoder, or the like. Among them, the servo motor is suitable for mounting an optical encoder, and the servo motor is a permanent magnet type synchronous motor, an induction motor driven by an inverter, or the like.

[0002]

2. Description of the Related Art FIG. 17 is a front view showing a cross section of a main part of a conventional servo motor. In the figure, the jacket 1 is formed of a bracket 1a on the driving side, a frame 1b, and a bracket 1c on the non-driving side. A stator and a rotor (not shown) are incorporated inside the outer cover 1. The drive shaft end 2a of the shaft penetrates the operating side of the jacket 1 and the shaft end 2b penetrates the non-operating side.

A mounting seat 201a is provided on the end face of the outer cover 1 on the side opposite to the driving side.
The module 3a of the optical encoder 3 is integrally incorporated in the encoder frame 201 attached by. The printed wiring board 4 is attached to a common end face of the support column 201b of the encoder frame 201 and the module 3a, and the electronic component 4 is attached to the printed wiring board 4.
a, etc. are implemented. The outer circumference of the rotary disc 3b of the optical encoder 3 is located in the groove 3s of the module 3a, and the rotary disc 3b is attached to the shaft end 2b penetrating the jacket 1 with the set screw 3d via the bush 3c. The rotating disc 3b and the bush 3c are fixed to each other with an instant adhesive or tightened with a ring nut, but the rotating disc 3b may be directly attached to the shaft end 2b. The module 3a has a light emitting element 3x and a light receiving element 3y, and light passes through a slit (not shown) of the rotating disc 3b. The encoder frame 201, the printed wiring board 3, and the optical encoder 4 are enclosed in a fully closed state by a cover 202 attached to the end face of the jacket 1 on the side opposite to the driving side for dustproofing, and the cable 5 penetrates the cable bush 203. Then, it is pulled out from the cover 202. The encoder frame 201 has a horseshoe shape such that the column 201b is not provided on the opposite side of the module 3a. Light emitting element 3 from this horseshoe-shaped gap
The groove 3 of the module 3a in which x and the light receiving element 3y are integrated.
The rotary disk 3b is inserted into s in the radial direction. Rotating disk 3
The relational dimension between b and the module 3a is also inspected and adjusted from the horseshoe-shaped gap of the encoder frame 201.

[0004]

In the above-mentioned conventional example, the encoder frame 201 and the cover 202 have a double structure.
Therefore, a gap between the encoder frame 201 and the cover 202 in the radial direction of a and b is defined as the electronic component 4 of the printed wiring board 4.
An axial gap c is required between a and the bottom of the cover 202. In addition, the mounting seat 2 of the encoder frame 201
The axial dimension of the servomotor increases by the thickness d of 01a.

An object of the present invention is to provide a servo motor which can eliminate the double structure of an encoder frame and a cover to reduce the space occupied by a rotary position detector such as an optical encoder and reduce the number of parts. It is in.

[0006]

In the servomotor of the invention 1, a cylindrical body is formed on an end surface of a motor casing on the side opposite to the driving side, and a printed wiring board is attached to the outer end surface of the cylindrical body in a fully closed state. The fixed portion of the rotary position detector is attached to the inside of the printed wiring board, and the rotary portion of the rotary position detector is attached to the end of the shaft that penetrates the jacket.

In the servomotor of the second aspect of the present invention, a cylindrical body is formed on the end surface of the motor casing on the side opposite to the driving side, and the printed wiring board is attached to the outer end surface of the cylindrical body in a fully closed state. The optical encoder module is installed inside so that the direction of light is axial, the outer circumference of the optical encoder's rotating disk is located in the groove of the module, and the rotating disk is installed at the shaft end that penetrates the jacket. A tubular body is provided with a cutout window that allows the module to pass in the radial direction and opens on the outer end surface, and a detachable window cover is attached to the cutout window. Servo motor to do.

According to a third aspect of the present invention, a bottom is formed on the electric motor side of the tubular body according to the second aspect, and a heat insulating means is interposed between the bottom and the end surface of the jacket. In the servomotor of the invention 4, a tubular body is formed on the end face of the electric motor on the side opposite to the driving side, the printed wiring board is attached to the outer end face of the tubular body in a fully closed state, and the optical wiring is provided inside the printed wiring board. The encoder module is mounted so that the light direction is axial, the outer circumference of the optical encoder's rotating disk is located in the groove of the module, and the rotating disk is installed at the shaft end that penetrates the jacket. A jig hole is opened in the axis of the board, a rotating disk can be attached to and detached from a jig that passes through the jig hole from the outside of the printed wiring board, and a hole plug can be attached to and removed from the jig hole. is there.

A fifth aspect of the present invention is the same as the fourth aspect, wherein the shaft end is provided with a mounting seat that fits into the shaft hole of the rotating disk and an axial screw hole.
The jig is a jig shaft that fits into the edge of the shaft hole, a ring that surrounds the jig shaft and fits into the jig hole, a bellows that is provided at the tip of the ring and that adheres closely to the rotating disk, and a jig. Formed from a flange that abuts the rotating disc by integrating the shaft and ring, vacuum means that can apply vacuum pressure is provided in the space between the bellows and the jig shaft, and the screw is screwed into the screw hole to rotate. A disc is attached to the shaft end.

In a sixth aspect of the present invention, in the fourth aspect, the rotating disk is fixed to the bush so that the bush projects from the shaft end, and the bush is provisionally fitted to the temporary shaft of the jig having the flange and the temporary shaft, so that A work window for temporarily fixing the bush to the shaft end is provided in the cylindrical body with a screw, and a window plug can be attached to and detached from the work window. A seventh aspect of the invention is the invention of the fourth aspect, wherein the jig is formed of a flange and a taper collet, and the taper collet is elastically and detachably fitted into a shaft hole of the rotating disc or a hole of a bush for fixing the rotating disc. It is a thing.

In the servomotor of the invention 8, a cylindrical body is formed on the end surface of the motor casing on the side opposite to the driving side, and the printed wiring board is attached to the outer end surface of the cylindrical body in a fully closed state. The module of the optical encoder is mounted inside so that the direction of the light is in the radial direction, the annular plate on the outer circumference of the rotating disk of the optical encoder is located in the groove of the module, and the rotating disk is at the shaft end that penetrates the jacket. Is attached.

In the servomotor of the invention 9, a printed wiring board is attached to a protrusion provided on the end surface of the motor casing on the side opposite to the driving side, and the optical encoder module is mounted on the outer end surface of the printed wiring board so that the direction of light is in the axial direction. , The outer circumference of the rotary disc of the optical encoder is located in the groove of the module, the rotary disc is attached to the shaft end that penetrates the jacket through the bush, and the printed wiring board, the optical encoder, and the bush are attached. In a servomotor in which and are surrounded by a cover in a fully closed state, an annular groove having a bottom inner diameter dimension α is formed in a bush having a thickness of γ, and an inner diameter β of an inner diameter β that is engaged with the annular groove in the printed wiring board A temporary holding hole and an insertion hole with an inner diameter δ are formed at a position eccentric in a direction away from the module in the radial direction. The temporary holding hole and the insertion hole are continuous at least in a continuous portion with a width β, and α <β <γ There is a relation of <δ.

In the servomotor according to the tenth aspect of the invention, the printed wiring board is attached to the protrusion provided on the end surface of the electric motor on the side opposite to the driving side, and the optical encoder module is mounted on the outer end surface of the printed wiring board so that the direction of light is axial. , The outer circumference of the rotary disc of the optical encoder is located in the groove of the module, the rotary disc is attached to the shaft end that penetrates the jacket through the bush, and the printed wiring board, the optical encoder, and the bush are attached. In a servomotor in which and are surrounded by a cover in a fully closed state, an annular groove having a bottom inner diameter dimension α is formed in a bush having a thickness of γ, and an inner diameter β of an inner diameter β that is engaged with the annular groove in the printed wiring board and is located at the axis center. A temporary holding hole is formed, and the temporary holding hole is cut out in the radial direction away from the module with a cutout having at least a width β, and has a relationship of α <β <γ.

In the servomotor of the eleventh aspect of the present invention, a cylindrical body is formed on the end surface of the outer casing of the electric motor on the non-driving side, and the printed wiring board is attached to the outer end surface of the cylindrical body in a fully closed state. One of the light emitting part and the light receiving part of the optical encoder is mounted inside so that the light is directed in the axial direction, and the other part is mounted on the end face of the jacket, and the optical encoder rotates between the one part and the other part. The outer periphery of the disc is located, a rotating disc is attached to the shaft end that penetrates the outer cover, and the light emitting portion and the light receiving portion are connected by electrical connecting means.

In the servomotor of the invention 12, a printed wiring board is attached to a protrusion provided on the end surface of the motor casing on the side opposite to the driving side, and one of the light emitting portion and the light receiving portion of the optical encoder is attached to the outer end surface of the printed wiring board. Part is attached so that the light is directed in the axial direction, and the other part is attached to the bottomed cylindrical encoder cover that is attached to the end face of the outer cover on the non-operation side, and the other part of the optical encoder is installed between the one part and the other part. The outer circumference of the rotating disk is located, the rotating disk is attached to the shaft end that penetrates the outer cover, and the light emitting section and the light receiving section are connected by electrical connection means.

[0016]

According to the first aspect of the present invention, since the tubular body and the printed wiring board also serve as the encoder frame and the cover, the double structure of the encoder frame and the cover is eliminated, and the rotary position detector and the printed wiring board are provided. The surrounding space is reduced and the number of parts is reduced.
Further, since the outside of the printed wiring board is exposed to the outside, cooling is improved.

According to the second aspect of the invention, since the tubular body and the printed wiring board also serve as the conventional encoder frame and cover, the double structure of the encoder frame and the cover is eliminated, and the optical encoder and the printed wiring board are eliminated. The surrounding space is reduced and the number of parts is reduced. Further, since the outside of the printed wiring board is exposed to the outside, cooling is improved. Assembly is simple, and the printed wiring board and the module are moved to their original positions by the module passing the notched window of the cylindrical body in the radial direction on the rotary disk attached to the shaft end. Since the notch window is open to the outer end surface of the tubular body, this radial passage is possible.

According to the invention 3, the heat of the electric motor is prevented from being conducted to the space for the optical encoder, the printed wiring board and the like. According to the invention 4, as in the invention 2, since the tubular body and the printed wiring board also serve as the conventional encoder frame and the cover, the double structure of the encoder frame and the cover is eliminated, and the optical encoder and the printing are provided. The occupied space around the wiring board shrinks,
The number of parts is reduced. Further, since the outside of the printed wiring board is exposed to the outside, cooling is improved. The assembly is simple, and the jig is inserted from the outside of the jig hole at the center of the printed wiring board to temporarily hold the rotating disk with the printed wiring board and the module. Then, these can be assembled by axially confronting the outer casing through which the shaft end penetrates.

According to the fifth aspect of the invention, the jig shaft, the ring, the bellows and the flange form a jig to temporarily hold the rotating disk with the printed wiring board or module. Since the screw hole for the screw that fixes the rotating disk to the shaft end faces the axial direction, the jig hole of the printed wiring board is also used for the screw tightening work of the driver.
According to the sixth aspect of the present invention, the flange and the temporary shaft form a jig to temporarily hold the rotating disk to the printed wiring board or module. After assembly, the screw that fixes the bush to the temporary shaft in the radial direction can be removed from the work window. Further, the working window 44 allows the positional relationship between the assembled module 3a and the rotating disk 3b to be reliably inspected.

According to the seventh aspect of the invention, the flange and the taper collet form a jig to temporarily hold the rotating disk to the printed wiring board or module. Does not require temporary holding screws. Invention 8
According to the invention, as in the second aspect, the tubular body and the printed wiring board are
Since it also serves as the encoder frame and the cover of the conventional example, the double structure of the encoder frame and the cover is eliminated, the exclusive space around the optical encoder is reduced, and the number of parts is reduced. Further, since the outside of the printed wiring board is exposed to the outside, cooling is improved. Since the annular plate is moved in the groove of the module in the axial direction for assembly, the assembly is easy, and a cutout window, a work window, or a jig is not required.

According to the ninth aspect of the invention, the protrusion is simple, the double structure of the conventional encoder frame and the cover is eliminated, the exclusive space around the optical encoder is reduced, and the number of parts is reduced. The assembling method of the present invention is such that the bush is axially inserted into the insertion hole at the eccentric position of the printed wiring board on the vertical axis, and then the bush is moved radially from the eccentric position to the axial center to form the annular groove of the bush. Engage the insertion holes in the printed wiring board. Since γ <δ, insertion is possible, and because α <β <γ, the annular groove and the insertion hole engage with each other, and the printed wiring board and the rotating disk should come off in directions other than the opposite direction of the movement. , The printed wiring board and the rotating disk form a temporary assembly. This temporary assembly is attached to the electric motor temporary assembly.

According to the tenth aspect of the invention, as in the ninth aspect of the invention, the protrusion is simple, and the dual structure of the encoder frame and the cover of the conventional example is eliminated to reduce the exclusive space around the optical encoder, and The points will decrease. The assembling method of the present invention is
The vertical axis is moved radially from the outer edge of the printed wiring board through the notch to engage the insertion hole of the printed wiring board with the annular groove of the bush. Since α <β <γ, the annular groove and the insertion hole are engaged with each other, and the printed wiring board and the rotating disk are not disengaged except in the opposite direction of the movement, and the printed wiring board and the rotating disk are separated from each other. Form a temporary assembly. This temporary assembly is attached to the electric motor temporary assembly.

According to the eleventh aspect of the present invention, since the tubular body and the printed wiring board also serve as the encoder frame and the cover of the conventional example, the double structure of the encoder frame and the cover is eliminated, and the peripheral area of the optical encoder is occupied. Space is reduced and the number of parts is reduced.
Further, since the outside of the printed wiring board is exposed to the outside, cooling is improved. Since the light emitting part and the light receiving part are separated, the assembly is simple, and the light emitting part, the rotating disk, and the printed wiring board on which the light receiving part is mounted are simply assembled in this order in the axial direction. Good.

According to the twelfth aspect of the invention, the protrusion is simple, the double structure of the encoder frame and the cover is eliminated, the exclusive space around the optical encoder is reduced, and the number of parts is reduced. Assembling is simple and the light emitting part and the light receiving part are separated, so the printed wiring board, the light receiving part, the rotary disk and the encoder cover with the light emitting part assembled on the outer cover are axially simple in this order. All you have to do is assemble.

[0025]

1 is a front view showing a cross section of a main part of a servomotor according to a first embodiment, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a view of a cylindrical body of FIG. 4 is a front view showing a cross section of a main part of a servo motor according to a second embodiment, FIG. 5 is a front view showing a cross section of a main part of a servo motor according to a third embodiment, and FIG. 6 is a front view showing an assembling method of FIG. 7 is a front view showing a cross section of a main part of a servo motor according to a fourth embodiment, FIG. 8 is a cross-sectional view taken along the line CC of FIG. 7, and FIG. 9 is a view illustrating a jig and a bush according to the fifth embodiment. FIG. 11 is a front view showing a partial cross section and a rotation-illustrated side surface, and FIG. 10 is a front view showing a cross section of a main part of a servomotor according to a sixth embodiment.
1 is a front view showing a cross section of a main part of a servomotor of Example 7,
FIG. 12 is a front view of the printed wiring board, module and rotating disk of FIG. 11, FIG. 13 is a front view of the printed wiring board and module of the eighth embodiment, and FIG. 14 is a diagram of the servomotor of the ninth embodiment. 15 is a front view showing a cross section taken along the line EE of FIG.
4 is a sectional view taken along line DD of FIG. 4, and FIG. 16 is a front view showing a sectional view of a main part of the servomotor of the tenth embodiment. In the conventional example and in each drawing, those denoted by the same reference numerals have approximately the same function, and duplicate explanation may be omitted.

In the first embodiment shown in FIGS. 1, 2 and 3, the jacket 1 is formed of a driving side bracket 1a, a frame 1b and an anti-driving side bracket 1c. A stator and a rotor (not shown) are incorporated inside the outer cover 1. The drive shaft end 2a of the shaft is on the operating side of the jacket 1 and the shaft end 2 is on the non-operating side.
b penetrates. The tubular body 11 is formed on the end surface of the outer cover 1 on the side opposite to the driving side, and the printed wiring board 4 is attached to the outer end surface of the tubular body 11 in a fully closed state. The module 3a of the optical encoder 3 is attached to the inside of the printed wiring board 4 such that the direction of light is in the axial direction. The optical encoder 3 is provided in the groove 3s of the module 3a.
The outer circumference of the rotating disk 3b is located, and the rotating disk 3b is attached to the shaft end 2b penetrating the jacket 1. The tubular body 11 is provided with a cutout window 12 through which the module 3a can pass in the radial direction and which opens to the outer end surface, and a detachable window cover 13 is attached to the cutout window 12.

The rotating disk 3b has a bush 3c at the shaft end 2b.
It is attached with the set screw 3d via the
The b and the bush 3c are fixed to each other with an instant adhesive or tightened with a ring nut. Further, the rotating disk 3b may be directly attached to the shaft end 2b. The module 3a has a light emitting element 3x and a light receiving element 3y, and light passes through a slit (not shown) of the rotating disc 3b. Although the cable 5 is pulled out from the window cover 13, the printed wiring board 4
Alternatively, the cable 5a may be drawn out from the outside of the cable like a chain line 5a. Inside the printed wiring board 4, electronic components 4
Although “a” or the like is mounted, an electronic component or the like, which itself has dust resistance and insulation properties and is strong against external force, may be mounted on the outside of the printed wiring board 4. The printed wiring board 4 may be one in which a conductor is printed and wired on an insulating board (referred to as an ordinary printed wiring board),
If a conductor is printed and wired on a metal plate through an insulating thin film (referred to as a metallic printed wiring board), cooling is further excellent.

According to the first embodiment, the tubular body 11 and the printed wiring board 4 have the encoder frame 201 and the cover 202 of the conventional example.
Since the double function of the encoder frame 201 and the cover 202 is eliminated, the exclusive space around the optical encoder 3 is reduced and the number of parts is reduced. Also, printed wiring board 4
Since the outside of the is exposed to the outside, cooling is improved. In particular, cooling is further improved by using a metallic printed wiring board.
The assembly of the first embodiment is simple, and the module 3a and the electronic component 4a are mounted on the inside of the printed wiring board 4 in which the rotary disk 3b is attached to the shaft end 2b. The notch window 12 is passed in the radial direction and moved to the original position. Since the notch window 12 is opened on the outer end surface of the tubular body 11, this radial passage is possible. Complete the assembly by tightening screws. The notch window 12 is also used when the set screw 3d is screwed to attach the rotating disk 3b to the shaft end 2b.

The second embodiment shown in FIG. 4 is different from the first embodiment in that a bottom 21 is formed on the electric motor side of the tubular body 11, and a heat insulating means is provided between the bottom 21 and the end face of the jacket 1. Is the point of being inserted. By providing the projection 22 on the end surface of the jacket 1 (or on the end surface of the bottom 21), the space 23 formed between the bottom 21 and the end surface of the jacket 1 serves as a heat insulating means. Packing 2
4 secures the dustproof property of the space for the optical encoder 3 and the like formed by the printed wiring board 4, the tubular body 11 and the bottom 21. Similarly, the dustproof property of the inside of the jacket 1 through which the shaft end 2b penetrates is secured. In addition to this structure, an ordinary heat insulating plate may be sandwiched between the bottom 21 and the end surface of the jacket 1. According to the second embodiment, the heat of the electric motor is prevented from being conducted to the space for the optical encoder 3 and the like.

The third embodiment shown in FIGS. 5 and 6 is the first embodiment.
Alternatively, the notch window 12 of the tubular body 11 according to the second embodiment is eliminated to enable the assembly in the axial direction even if the rotating disk 3b interferes with the groove 3s of the module 3a in the axial direction. Is. In the figure, a tubular body 11 is formed on the end face of the outer cover 11 on the non-driving side, and the printed wiring board 4 is attached to the outer end face of the tubular body 11 in a fully closed state. The module 3a of the optical encoder 3 is attached to the inside of the printed wiring board 4 such that the direction of light is in the axial direction. The outer circumference of the rotary disc 3b of the optical encoder 3 is located in the groove 3s of the module 3a, and the rotary disc 3b is directly attached to the shaft end 2b penetrating the outer cover 11 without the bush 3c. The rotating disk 3b is fixed by the washer 2c and the screw 2d. The structure up to this point is different only in the mounting structure of the rotating disk 3b and the shaft end 2b, and the other structure is the same as that of the first or second embodiment. As a supplementary note, the mounting structure of the rotating disk 3b and the shaft end 2b may be the structure of the third embodiment in the first and second embodiments.

A feature of the third embodiment is that a jig hole 31 is formed in the shaft center of the printed wiring board 4, and the rotary disc 3b is attached to and detached from a jig 32 that is inserted from the outside of the printed wiring board 4 into the jig hole 31. Enabled A hole plug 33 is detachably attached to the jig hole 31, and the hole plug 33 is attached in the final step of assembly to ensure dustproofness. The shaft end 2b includes a mounting seat 2e that fits into the shaft hole 3e of the rotating disc 3b and a screw hole 2f. The detailed structure of the jig 32 will be described with reference to FIG. The jig 32 includes a jig shaft 32a fitted to the edge of the shaft hole 3e, and the jig hole 3 surrounding the jig shaft 32a.
1 includes a ring 32b, a bellows 32c provided at the tip of the ring 32b and closely attached to the rotating disc 3b, and a flange 32d that abuts against the printed wiring board 4 by integrating the jig shaft 32a and the ring 32b. It is formed. Bellows 32
Vacuum means 32e capable of applying a vacuum pressure is provided in the space between c and the jig shaft 32a. The rotating disk 3b is attached to the shaft end 2b by screwing the screw 2d into the screw hole 2f.

The assembling method of the third embodiment will be described. Jig hole 3
1 is fitted with the ring 32b of the jig 32 and the flange 32
After bringing d into contact with the printed wiring board 4, the jig shaft 32a is fitted with the edge of the shaft hole 3e of the rotating disk 3b to form the vacuum means 32e.
Is operated, the bellows 32c is attracted to the rotating disc 3b. In this way, the rotating disk 3b is temporarily held on the printed wiring board 4 via the jig 32. At this time, the module 3a
The outer periphery of the rotating disk 3b is located in the groove 3s of the module 3
It is possible to maintain the original correct positional relationship between a and the rotating disk 3b. Thereafter, the printed wiring board 4, the module 3a, and the rotating disk 3b that are temporarily held by the jig 32 are moved in the axial direction by the jacket 1 having the shaft end 2b, and the shaft end 2b is moved.
When the shaft hole 3e of the rotating disk 3b is fitted into the
e is released and the jig 32 is removed. The rotating disk 3b is fixed to the shaft end 2b with a screw 2d. At the same time, the printed wiring board 4 is fixed to the tubular body 11 with bolts or the like not shown. The hole plug 33 is attached to the jig hole 31, and the assembly is completed.

According to the third embodiment, as in the first embodiment, the tubular body 11 and the printed wiring board 4 are the same as the encoder frame 2 of the conventional example.
01 and the cover 202, the encoder frame 20
The dual structure of 1 and the cover 202 is eliminated, the exclusive space around the optical encoder 3 is reduced, and the number of parts is reduced.
Further, since the outside of the printed wiring board 4 is exposed to the outside, cooling is improved. In particular, cooling is further improved by using a metallic printed wiring board. Compared to the first embodiment, the jig 32 is required, but the jig hole 31 is replaced with the hole plug 3 instead of the notch window 12.
Since the dustproof property is maintained at 3, the dustproof property is sure.

A feature of the fourth embodiment shown in FIGS. 7 and 8 is that a jig hole 41 is formed in the shaft center of the printed wiring board 4 and the jig 42 is inserted from the outside of the printed wiring board 4 into the jig hole 41. The rotating disk 3b is detachable. Hole plug 43 in the jig hole 41
Is removable. In this case, the rotating disk 3b is fixed to the bush 3c so that the bush 3c projects from the shaft end 2b. The bush 3c is temporarily fitted to the temporary shaft 42b of the jig 42 having the flange 42a and the temporary shaft 42b, and can be temporarily fixed by the radial screw 42c. Bush 3c to shaft end 2
A work window 44 for fixing to b is provided in the tubular body 11, and a window plug 45 can be attached to and detached from the work window 44.

The assembling method of the fourth embodiment will be described. Jig hole 4
1. Fit the temporary shaft 42b of the jig 42 into the flange 42a
Is brought into contact with the printed wiring board 4, and then the bush 3c of the rotating disk 3b is fitted to the temporary shaft 42a and temporarily fixed by the screw 42c. In this way, the rotating disc 3b is temporarily held on the printed wiring board 4 via the jig 42, and the module 3a and the rotating disc 3 are held.
It is possible to maintain the original correct positional relationship with b. Thereafter, the printed wiring board 4, the module 3a, and the rotating disk 3b that are temporarily held by the jig 42 are moved in the axial direction by the jacket 1 having the shaft end 2b, and the rotating disk 3b is moved to the shaft end 2b. The bush 3c is fitted. The rotating disk 3b is fixed to the shaft end 2b with the set screw 3d using the work window 44. At the same time, the printed wiring board 4 is fixed to the tubular body 11 with bolts or the like not shown. Then, screw 42c to work window 44
Then, the jig 42 is removed by removing with a driver 46. The hole plug 43 is attached to the jig hole 41 and the window plug 45 is attached to the work window 44, and the assembly is completed.

According to the fourth embodiment, similarly to the first embodiment, the tubular body 11 and the printed wiring board 4 are the same as the encoder frame 2 of the conventional example.
Since it also serves as 01 and the cover 202, the double structure is eliminated, the exclusive space around the optical encoder 3 is reduced, and the number of parts is reduced. Further, since the outside of the printed wiring board 4 is exposed to the outside, cooling is improved. Jig 4 compared to Example 1
2 is required, but since the jig hole 41 is replaced by the hole plug 43 and the work window 44 is protected by the window plug 45 in place of the cutout window 12, the dustproof property is ensured, and the work window 44 is assembled. The subsequent positional relationship between the module 3a and the rotating disk 3b can be reliably inspected. When a long screw in which the screw 42c and the driver 46 are integrated is used, the work window 44 is a cutout window that opens to the outer end surface of the tubular body 11.

A feature of the fifth embodiment shown in FIG. 9 is that the jig 5 is used.
2 is formed of a flange 52a and a tapered collet 52b. The taper collet 52b is elastically and detachably fitted into the hole of the bush 3c for fixing the rotating disc 3b (or directly to the shaft hole of the rotating disc 3b (the same as the shaft hole 3e of the third embodiment)). To do. Other structures and assembling methods are described in the third embodiment.
And the same as Example 4. According to the fifth embodiment, the fourth embodiment
In addition to the effects of the above, the temporary fixing screw and its attachment / detachment in the fourth embodiment are unnecessary.

In Example 6 shown in FIG. 10, a tubular body 11 is formed on the end face of the motor casing 1 on the side opposite to the driving side, and the printed wiring board 4 is attached to the outer end face of the tubular body 11 in a fully closed state. To be The module 63a of the optical encoder 63 is mounted inside the printed wiring board 4 so that the direction of light is directed in the radial direction.
The annular plate 63c on the outer periphery of the rotating disc 63b of the optical encoder 63 is located in the groove 63s of the module 63a. A rotary disc 63b is attached to a shaft end 2b penetrating the jacket 1 via a bush 63d.

According to the sixth embodiment, as in the first embodiment, the tubular body 11 and the printed wiring board 4 are arranged in the same manner as the encoder frame 2 of the conventional example.
01 and the cover 202, the encoder frame 20
The dual structure of 1 and the cover 202 is eliminated, the exclusive space around the optical encoder 3 is reduced, and the number of parts is reduced.
Further, since the outside of the printed wiring board 4 is exposed to the outside, cooling is improved. In particular, cooling is further improved by using a metallic printed wiring board. In the sixth embodiment, the rotary disc 63b is provided with the annular plate 63 having a slit (not shown), which is difficult to manufacture, but the annular plate 6 is provided in the groove 63s of the module 63a.
Since 3c is moved in the axial direction for assembly, there is an advantage that the assembly is easy and a cutout window, a working window, and a jig are not required.

In the seventh embodiment shown in FIGS. 11 and 12, the jacket 1 is formed of a driving side bracket 1a, a frame 1b and a non-driving side bracket 1c. A stator and a rotor (not shown) are incorporated inside the outer cover 1. The drive shaft end 2a of the shaft is on the operating side of the jacket 1 and the shaft end 2 is on the non-operating side.
b penetrates. It is the same as the conventional example. As a feature of the embodiment, a printed wiring board 72 is attached to a protrusion 71 provided on an end surface of the jacket 1 on the side opposite to the driving side, and the module 3a of the optical encoder 3 has an axial direction of light on the outer end surface of the printed wiring board 72. It is mounted so that it faces the. The electronic component 4a and the like are mounted on the printed wiring board 72. The outer circumference of the rotary disk 3b of the optical encoder 3 is located in the groove 3s of the module 3a, and the rotary disk 3b is attached to the shaft end 2b penetrating the jacket 1 via the bush 73. Printed wiring board 72, optical encoder 3, and bush 7
3 and 3 are surrounded by a cover 74 in a fully closed state. Compared to the conventional example, the printed wiring board 72 and the rotating disc are axially reversed in position in structure.

As a structure and dimensional characteristics, an annular groove 73a having a bottom inner diameter α is formed in a bush 73 having a thickness γ. On the other hand, the provisional holding hole 72a of the inner diameter β located at the axis B by engaging the annular groove 73a on the printed wiring board 72, and the module 3
An insertion hole 72b having an inner diameter δ is formed at a position A that is eccentric in a direction away from a in the radial direction, and the temporary holding hole 72a and the insertion hole 7 are formed.
2b is continuous with at least a continuous portion 72c having a width β. The dimensional relationship is α <β <γ <δ.

According to the seventh embodiment, the protrusion 71 is simple, the double structure of the conventional encoder frame 201 and the cover 202 is eliminated, and the exclusive space around the optical encoder 3 is reduced. The points will decrease. A characteristic assembling method of the seventh embodiment will be described. The shaft end 2b is projected from the outer cover 1 to assemble a temporary electric motor assembly. A bush 73 having the rotating disk 3b fixed thereto and a printed wiring board 72 having the module 3a and the electronic component 4a mounted thereon are prepared. With the vertical axis, the insertion hole 7 at the eccentric position A of the printed wiring board 72
2b, the bush 73 is inserted in the axial direction, and then the bush 73 is moved from the position A to the axial center B in the radial direction as shown by the arrow P to form the insertion hole 72b of the printed wiring board 72 in the annular groove 73a of the bush 73. Engage. Since γ <δ, insertion is possible, and because α <β <γ, the annular groove 73a and the insertion hole 72b are engaged with each other, and the printed wiring board 72 and the rotary disk 3b are in directions other than the direction opposite to the arrow P. The printed wiring board 72 and the rotating disk 3b form a temporary assembly. This temporary assembly is attached to the electric motor temporary assembly, and the screw 75 and the set screw 3d are tightened.

The eighth embodiment shown in FIG. 13 is the same as the seventh embodiment except for the printed wiring board.
The bush 73 is formed with an annular groove 73a having an inner diameter dimension α of the bottom. On the other hand, the printed wiring board 82 is provided with a temporary holding hole 82a having an inner diameter β and located at the axial center by engaging with the annular groove 73a.
The temporary holding hole 82a is notched in the outer edge of the printed wiring board 82 by a notch 82b having a width β at least in the direction away from the module 3a in the radial direction. The dimensional relationship is α <β <γ.

According to the eighth embodiment, as in the seventh embodiment, the double structure of the encoder frame 201 and the cover 202 of the conventional example is eliminated, the exclusive space around the optical encoder 3 is reduced, and the number of parts is reduced. Decrease. In the assembling method of the eighth embodiment, instead of inserting the bush 73 through the insertion hole 72b, the bushing 73 is inserted from the outer edge of the printed wiring board 82 through the notch 82b. 14
And in Example 9 shown in FIG. 15, the jacket 1 is formed of a bracket 1a on the driving side, a frame 1b, and a bracket 1c on the non-driving side. A stator and a rotor (not shown) are incorporated inside the outer cover 1. The drive shaft end 2a of the shaft penetrates the operating side of the jacket 1 and the shaft end 2b penetrates the non-operating side.

A feature of the embodiment is that a tubular body 11 is formed on the end face of the outer casing 1 on the side opposite to the driving side, and the printed wiring board 4 is attached to the outer end face of the tubular body 11 in a fully closed state with a screw 11a. The light receiving portion 91y of the optical encoder 91 is mounted inside the printed wiring board 4 together with the electronic component 4a so that the light is directed in the axial direction. The light emitting portion 91x is attached to the end surface of the jacket 1 with a screw 91a. The outer circumference of the rotating disk 3b of the optical encoder 91 is located between the light emitting section 91x and the light receiving section 91y, and the rotating disk 3b is attached to the shaft end 2b penetrating the jacket 1 via the bush 3c. 91x and the light-receiving part 91y are connected by the connector 92 which has a male connector and a female connector.
The connector 92 may be an electrical connection means such as a vinyl insulated wire or a flexible printed wiring board. The printed wiring board 4 may be an ordinary printed wiring board, but if it is a metallic printed wiring board, the printed wiring board 4 is strong against external force and further excellent in cooling. Further, the light emitting portion 91x and the light receiving portion 91y may be exchanged with each other, but it is advantageous to attach the light receiving portion 91y having many output terminals to the printed wiring board 4. In order to accurately align the mutual positional relationship of the optical axes of the light emitting portion 91x and the light receiving portion 91y and the positional relationship with these axial centers, ordinary positioning pins and holes are used. The light receiving portion 91y is mounted on the printed wiring board 4 by the lead 91b. A cable 5 may be mounted on the printed wiring board 4.

According to the ninth embodiment, the tubular body 11 and the printed wiring board 4 are the encoder frame 201 and the cover 202 of the conventional example.
Since the double structure of the encoder frame 201 and the cover 202 is eliminated, the exclusive space around the optical encoder 91 is reduced, and the number of parts is reduced. Further, since the outside of the printed wiring board 4 is exposed to the outside, cooling is improved. In particular,
Cooling is even better with metallic printed wiring boards. Assembling is simple, and conventionally, the rotary disc 3b is radially inserted from the horseshoe-shaped gap of the encoder frame 201 into the groove 3s of the module 3a in which the light emitting element 3x and the light receiving element 3y are integrated. In the embodiment, since the light emitting part 91x and the light receiving part 91y are separated, the light emitting part 91x, the rotating disk 3b, and the printed wiring board 4 on which the light receiving part 91y is mounted are axially arranged in this order in the jacket 1. All you have to do is assemble it easily.

In the tenth embodiment shown in FIG. 16, the jacket 1
Of the printed wiring board 10 on the projection 101 provided on the end face on the side opposite to the driving side of
2 is attached. The light receiving portion 103y of the optical encoder 103 is attached to the outer end surface of the printed wiring board 102 so that the light is directed in the axial direction. The light emitting portion 103x is attached to the bottomed cylindrical encoder cover 104 attached to the end surface of the outer cover 1 on the side opposite to the operation side. The outer circumference of the rotating disk 3b of the optical encoder 103 is located between the light emitting section 103x and the light receiving section 103y, and the rotating disk 3b is attached to the shaft end 2b penetrating the jacket 1. The light emitting unit 103x and the light receiving unit 103y are connected to the connector 92.
Connected by.

According to the tenth embodiment, the protrusion 101 is simple, the double structure of the encoder frame 201 and the cover 202 is eliminated, the exclusive space around the optical encoder 103 is reduced, and the number of parts is reduced. To do. Assembling is similar to that of the ninth embodiment, and since the light emitting portion 103x and the light receiving portion 103y are separated, the printed wiring board 102, the light receiving portion 103y, the rotating disk 3b, and the light emitting portion 103x are provided on the outer cover 1. It suffices to simply assemble the encoder cover 104 in which the above is assembled in this order in the axial direction.

[0049]

According to the servo motor of the invention 1, since the printed wiring board is mounted on the outer end surface of the cylindrical body in a fully closed state, the double structure of the encoder frame and the cover is eliminated, and the rotary position detector. Also, there is an effect that the exclusive space around the printed wiring board is reduced and the number of parts is reduced. Further, since the outside of the printed wiring board is exposed to the outside, there is an effect that cooling is improved. According to the servo motor of the invention 2, since the printed wiring board is attached to the outer end surface of the cylindrical body in a fully closed state, the double structure of the encoder frame and the cover is eliminated, and the peripheral portion of the optical encoder or the printed wiring board is eliminated. There is an effect that the exclusive space is reduced and the number of parts is reduced, and there is an effect that cooling is improved because the outside of the printed wiring board is exposed to the outside. Since the cutout window is open to the outer end surface of the tubular body, the printed wiring board and module can be assembled by moving the module through the cutout window of the tubular body in the radial direction to the original position. The effect is that it will be possible.

According to the third aspect of the invention, the heat insulation means has an effect of preventing heat of the electric motor from being conducted to the space for the optical encoder, the printed wiring board and the like. According to the invention 4, since the printed wiring board is attached to the outer end surface of the tubular body in a fully closed state, the double structure of the encoder frame and the cover is eliminated, and the exclusive space around the optical encoder and the printed wiring board is provided. There is an effect that the size of the printed wiring board is reduced and the number of parts is reduced. Further, since the outside of the printed wiring board is exposed to the outside, cooling is improved. Since a jig hole to which a jig can be applied is provided in the printed wiring board and the rotary disk is temporarily held with the printed wiring board and the module, there is an effect that a notched window which is disadvantageous in dustproofness can be eliminated.

According to the fifth aspect of the invention, since the screw for fixing the rotating disk to the shaft end faces in the axial direction, the jig hole of the printed wiring board is also used for the work of the screw tightening driver, and the cutout window is formed. It has the effect of being eliminated. According to the sixth aspect of the invention, there is an effect that the positional relationship between the assembled module and the rotating disk can be surely inspected by the work window.

According to the seventh aspect of the invention, there is an effect that a temporary holding screw is unnecessary. According to the eighth aspect of the invention, since the printed wiring board is attached to the outer end surface of the tubular body in a fully closed state, the double structure of the encoder frame and the cover is eliminated, and a dedicated space around the optical encoder and the printed wiring board is provided. There is an effect that the size of the printed wiring board is reduced and the number of parts is reduced. Further, since the outside of the printed wiring board is exposed to the outside, cooling is improved. Since the annular plate is moved in the groove of the module in the axial direction for assembly, the assembly is easy and there is an effect that a cutout window, a work window, or a jig is not required.

According to the ninth or tenth aspect of the invention, the simple structure eliminates the double structure of the encoder frame and the cover of the conventional example, reduces the space occupied by the optical encoder, and reduces the number of parts. effective. In assembly,
Since the insertion hole or notch is used in the printed wiring board, there is an effect that the problem that the printed wiring board and the module geometrically interfere with each other in the axial direction at the original position is solved. The effect is that the inspection and adjustment of is easy.

According to the servomotor of the eleventh aspect of the present invention, the double structure of the encoder frame and the cover is eliminated by the cylindrical body and the printed wiring board, the exclusive space around the optical encoder is reduced, and the number of parts is reduced. The outer side of the printed wiring board is exposed to the outside so that cooling is improved. Since the light emitting portion and the light receiving portion are separated, there is an effect that the assembling is simple and only the axial direction is required.

According to the servo motor of the twelfth aspect, the protrusion is simple, the dual structure of the encoder frame and the cover is eliminated, and the exclusive space around the optical encoder is reduced,
This has the effect of reducing the number of parts. Since the light emitting portion and the light receiving portion are separated, there is an effect that the assembling is simple and only the axial direction is required.

[Brief description of drawings]

FIG. 1 is a front view showing a cross section of a main part of a servo motor according to a first embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a view of the cylindrical body of FIG. 2 as seen from the direction of arrow B.

FIG. 4 is a front view showing a cross section of a main part of a servo motor according to a second embodiment.

FIG. 5 is a front view showing a cross section of a main part of a servo motor according to a third embodiment.

FIG. 6 is a front view showing the assembly method of FIG.

FIG. 7 is a front view showing a cross section of a main part of a servo motor according to a fourth embodiment.

FIG. 8 is a sectional view taken along line CC of FIG.

FIG. 9 is a front view showing a cross section of a main part of a jig and a bush according to a fifth embodiment and a rotationally illustrated side surface.

FIG. 10 is a front view showing a cross section of a main part of a servo motor according to a sixth embodiment.

FIG. 11 is a front view showing a cross section of a main part of a servo motor according to a seventh embodiment.

12 is a front view of the printed wiring board, module, and rotating disk of FIG.

FIG. 13 is a front view of a printed wiring board and a module of Example 8.

FIG. 14 is a main part E-E of FIG. 2 of the servomotor of Example 9;
Front view showing cross section

FIG. 15 is a sectional view taken along line DD of FIG.

FIG. 16 is a front view showing a cross section of a main part of a servo motor according to a tenth embodiment.

FIG. 17 is a front view showing a cross section of a main part of a conventional servo motor.

[Explanation of symbols]

1 Jacket 1a Bracket 1b Frame 1c Bracket 2a Drive shaft end 2b Shaft end 2c Washer 2d Screw 2e Mounting seat 2f Screw hole 3 Optical encoder 3a Module 3b Rotating disc 3c Bushing 3d Set screw 3e Shaft hole 3s Groove 3x Light emitting element 3y Element 4 Printed wiring board 5 Cable 5a Cable 11 Cylindrical body 12 Cutout window 13 Window cover 21 Bottom 22 Protrusion 23 Space 24 Packing 31 Jig hole 32 Jig 32a Jig shaft 32b Ring 32c Bellows 32d Flange 32e Vacuum means 33 hole Plug 71 Protrusion 72 Printed wiring board 72a Temporary holding hole 72b Insertion hole 72c Continuous portion 73 Bushing 73a Annular groove 74 Cover 91 Optical encoder 91x Light emitting portion 91y Light receiving portion 92 Connector 101 Protrusion 102 Printed wiring board 103 Optical encoder 1 3x emitting portion 103y receiving unit 104 encoder cover

Claims (12)

[Claims] 1. A cylindrical body is formed on an end surface of an outer casing of an electric motor on a side opposite to a driving side, a printed wiring board is attached to the outer end surface of the cylindrical body in a fully closed state, and a rotational position is detected inside the printed wiring board. A servo motor in which a fixed portion of the rotary position detector is attached to a shaft end that penetrates the outer cover. 2. A tubular body is formed on an end surface of the outer casing of the electric motor on the side opposite to the driving side, a printed wiring board is attached to the outer end surface of the tubular body in a fully closed state, and an optical encoder is provided inside the printed wiring board. The module is mounted so that the direction of light is in the axial direction, the outer circumference of the rotating disc of the optical encoder is located in the groove of the module, and the rotating disc is attached to the shaft end that penetrates the outer casing. A servo motor characterized in that a notch window that allows the module to pass in the radial direction and opens to the outer end surface is provided, and a detachable window cover is attached to the notch window. 3. The servomotor according to claim 2, wherein a bottom is formed on the electric motor side of the tubular body, and a heat insulating means is interposed between the bottom and the end surface of the jacket. Servomotor. 4. A cylindrical body is formed on an end surface of the outer cover of the electric motor on the non-driving side, a printed wiring board is attached to the outer end surface of the cylindrical body in a fully closed state, and an optical encoder is provided inside the printed wiring board. The module is mounted so that the direction of light is in the axial direction, the outer circumference of the rotary disc of the optical encoder is located in the groove of the module, and the rotary disc is mounted on the shaft end that penetrates the outer cover. A jig hole is opened in the shaft center, a rotating disk can be attached to and detached from a jig that is inserted through the jig hole from the outside of the printed wiring board, and a hole plug can be attached to and detached from the jig hole. Servo motor to do. 5. The servomotor according to claim 4, wherein the shaft end is provided with a mounting seat that fits into the shaft hole of the rotating disk and a screw hole in the axial direction, and the jig fits into the edge of the shaft hole. A jig shaft, a ring surrounding the jig shaft and fitted in a jig hole, a bellows provided at the tip of the ring and in close contact with the rotating disk, and the jig shaft and the ring are integrated to form a rotating disk. It is characterized in that it is formed with a flange that abuts against, a vacuum means that can apply a vacuum pressure is provided in the space between the bellows and the jig shaft, and that the screw is screwed into the screw hole and the rotating disk is attached to the shaft end. Servo motor to be. 6. The servomotor according to claim 4, wherein the rotating disk is fixed to the bush, the bush projects from the shaft end, and the bush is temporarily fitted to the temporary shaft of a jig having a flange and a temporary shaft. It is possible to temporarily fix with a screw in the radial direction, a working window for fixing the bush to the shaft end is provided in the cylindrical body,
Servo motor characterized in that a window plug can be attached to and detached from the work window. 7. The servomotor according to claim 4, wherein the jig is formed of a flange and a taper collet, and the taper collet is elastically arranged in a shaft hole of the rotating disk or a hole of a bush for fixing the rotating disk. A servo motor characterized by being detachably fitted. 8. A tubular body is formed on an end surface of the outer casing of the electric motor on the side opposite to the operation side, a printed wiring board is attached to the outer end surface of the tubular body in a fully closed state, and an optical encoder is provided inside the printed wiring board. The module is mounted so that the direction of light is directed in the radial direction, the annular plate on the outer circumference of the rotary disc of the optical encoder is located in the groove of the module, and the rotary disc is mounted on the shaft end that penetrates the outer cover. Characteristic servo motor. 9. A printed wiring board is attached to a protrusion provided on the end surface of the motor casing on the side opposite to the driving side, and an optical encoder module is attached to the outer end surface of the printed wiring board so that the direction of light is in the axial direction. The outer circumference of the rotary disc of the optical encoder is located in the groove of the module, and the rotary disc is attached to the shaft end that penetrates the jacket through the bush, and the printed wiring board, the optical encoder, and the bush are all covered by the cover. In a servo motor enclosed in a closed state, a bush with a thickness of γ has an annular groove with an inner diameter of α at the bottom, and the printed wiring board has an inner diameter β that engages with the annular groove and is located at the shaft center.
, And an insertion hole with an inner diameter δ is formed at a position that is eccentric in the direction away from the module in the radial direction. The temporary holding hole and the insertion hole are continuous at least in a continuous portion of width β, and α <β < A servo motor having a relationship of γ <δ. 10. A printed wiring board is attached to a protrusion provided on an end surface of an outer casing of an electric motor on a side opposite to a driving side, and an optical encoder module is attached to an outer end surface of the printed wiring board so that a light direction is directed in an axial direction. The outer circumference of the rotary disc of the optical encoder is located in the groove of the module, and the rotary disc is attached to the shaft end that penetrates the jacket through the bush, and the printed wiring board, the optical encoder, and the bush are all covered by the cover. In a servo motor enclosed in a closed state, a bush with a thickness of γ has an annular groove with an inner diameter of α at the bottom, and the printed wiring board has an inner diameter β that engages with the annular groove and is located at the shaft center.
And a temporary holding hole is formed in the outer edge of the printed wiring board by a notch having at least a width β in the direction away from the module in the radial direction, and α <β <γ is satisfied. Servomotor. 11. A cylindrical body is formed on an end surface of an outer casing of an electric motor on the side opposite to the driving side, a printed wiring board is attached to the outer end surface of the cylindrical body in a fully closed state, and an optical encoder of the inside is attached to the printed wiring board. One of the light emitting part and the light receiving part is attached so that the light is directed in the axial direction, the other part is attached to the end surface of the outer cover, and the outer circumference of the rotary disk of the optical encoder is located between the one part and the other part. A servomotor characterized in that a rotating disk is attached to a shaft end which is located and penetrates an outer cover, and the light emitting portion and the light receiving portion are connected by an electrical connecting means. 12. A printed wiring board is attached to a protrusion provided on an end surface of an outer casing of an electric motor on a side opposite to a driving side, and one of a light emitting portion and a light receiving portion of an optical encoder has an optical axis on the outer end surface of the printed wiring board. The other side is attached to the bottomed cylindrical encoder cover that is attached to the end face on the non-operation side of the jacket, and the outer circumference of the rotating disk of the optical encoder is between the one side and the other side. Is located, a rotary disk is attached to the shaft end that penetrates the outer cover, and the light emitting portion and the light receiving portion are connected by an electrical connecting means.