JPS5939705B2 - limited rotary galvanometer - Google Patents

Description

[Detailed description of the invention] This invention relates to a galvanometer and its stator assembly.

This type of assembly must be rigidly constructed to ensure accuracy during operation and also to resist honing of the cylindrical internal pole face of the stator assembly forming the space for the galvanometer rotor. No. To provide rigidity, the laminated stator pieces with the coils in place are usually aligned with each other and with loaded magnets and a suitable jig, with rivets or screws between the top and bottom plates. The screws are tightened, the jig is removed and the assembly is placed into an aluminum can.

Honing of the stator pole faces is then performed to couple proper alignment of the faces with the subsequently installed rotor. One disadvantage of such current configurations is that when the jig is removed, a stress is released and the laminate pieces spring back to some degree, resulting in misalignment of the individual laminate pieces and increasing the need for honing. do. A significant percentage of assemblies may be discarded because the misalignment is too severe to be corrected by honing. Another disadvantage of such a construction is that enveloping with epoxy is labor intensive, requiring partial filling and froth removal before complete filling. The epoxy enclosure is also somewhat fragmentable, allowing movement of the stator relative to its mount.
Furthermore, in conventional galvanometers having iron rotors, the stator components are subject to large reaction forces from the rotor, and microscopic movement of components within the stator components is likely to occur. These movements create deleterious hysteresis which has a very large effect on the rotor positional accuracy. Welding the laminates to overcome some of these drawbacks increases manufacturing costs considerably. The inventors believe that injection molding a hard thermoplastic outer layer that cools, solidifies and contracts around the galvanometer stator creates a circumferential tension that securely holds the stator parts together and provides even greater flexibility at less cost. We have discovered that it can be useful in making effective galvanometers.

The stiff layer eliminates the need for epoxy enclosures or aluminum cans, reduces the need for honing, and reduces movement of the stator parts themselves and their interiors more than in galvanometer assemblies with conventional iron rotors. can be made significantly smaller to prevent harmful hysteresis from occurring. The hard molded layer also allows the use of sintered stator pieces, which eliminates the additional problems and costs associated with stators formed from laminate pieces. The invention therefore features a limited rotary galvanometer having a multi-part stator and a rotor mounted for rotation on an axis relative to the stator.

According to the invention, a molded outer layer of hard thermoplastic material extends around the stator and is subjected to circumferential tension as a result of shrinkage and solidification of the thermoplastic material upon cooling after molding. This layer serves to securely hold the stator parts against movement. The invention also provides a section of rigid synthetic material that is integral with the layer surrounding the galvanometer and serves to house and position each of a set of electrical connector members for engagement with an external connector. It is characterized by

This device avoids the problem during molding of plastic leaking along previously used flexible electrical leads, and achieves an inexpensive configuration that is easily attached to external circuitry. . Preferably the housed electrical connector is a rigid pin insulated from each other by a molded material, and the electrical connector member is embedded in the molded material and preferably has a central hole and It is connected to a printed wiring board surrounding the rotor,
The electrical connector members are grouped to receive the external plug, and a detent molded of a rigid material, preferably a molded cantilever spring, retains the plug. In a preferred arrangement, the galvanometer has at least one permanent magnet and a hard thermoplastic layer presses the stator parts and the magnet together to maintain them in a fixed position, thereby providing a constant The magnetic properties are maintained in a magnetic circuit established between the stator and the magnets, with stator parts on each side of the rotor axis and a magnetic circuit between opposing stator parts on each side of the rotor axis. There are a pair of magnets, one of which is located at the top, and the stator parts are held together prior to molding by a mechanical retention device which alone cannot properly hold the stator pieces in the correct position during operation of the galvanometer. A mechanical retainer is embedded in a hard thermoplastic layer that secures the stator parts against movement, and the stator consists of at least two shaped sintered metal pieces placed around the rotor. and the shaped sintered piece has a holding device formed on the outside of the sintered piece held by the holding device, and the shaped sintered piece has no holes. , the retainable formation has an external groove, and the mechanical retaining device has a retaining pin in the groove and engaging the sides of the groove, and the stator is vertically It has a plurality of nearly identical planar metal laminates stacked one on top of the other, with a hard thermoplastic layer molded around the laminates that binds the laminates to each other and to the rotor. The coils wrapped around the stator are embedded in an injection molded material that is integrated with a hard thermoplastic layer to help keep it in a fixed position. Made of nylon reinforced with a glass-like material and at least 0.5 mm thick, the hard thermoplastic outer layer is oriented around the axis of the stator and around the end plates thereof. The layers are molded around the stator in both directions, and in either direction the layers are under circumferential tension as a result of the solidification and shrinkage of the thermoplastic material after molding, which serves to securely fasten the stator parts. There is.

The invention also includes the steps of preparing a stator having a plurality of parts to receive a rotor rotating on an axis relative to the stator, including an outer layer of hard thermoplastic material extending around the stator. the step of injection molding (the material is allowed to shrink upon cooling from its molding temperature) and cooling, solidifying and shrinking the material so that it is permanently under circumferential tension, thereby causing the outer layer to The present invention features a method of manufacturing a limited rotary galvanometer having the steps of: helping to securely fix stator parts against movement;

Preferably, the molding step involves introducing a thermoplastic material in such a way that the mold is placed close around the stator and magnet parts to produce a continuous layer surrounding said parts, and the circumference generated by this layer is The method of manufacture consists of forcing the stator parts and the magnets together due to tension to create a magnetic circuit with constant magnetic properties, and the manufacturing method includes a A stator part in the form of a burnt metal piece is provided, which alone cannot secure this metal piece during operation of the galvanometer.

the metal piece by a mechanical retention device engaged with the grippable formation, and the injection molding step includes embedding the retention device in the thermoplastic layer. and the cooling step creates a circumferential tension that secures the metal pieces against movement relative to the rotor axis, and the manufacturing method provides a stator component in the form of a plurality of substantially identical planar metal laminate pieces. The tightening step includes aligning the laminates with respect to mandrels in a vertical stack that are arranged to align the pole faces of the laminates with respect to the rotor axis, and the The steps include introducing a thermoplastic material while aligning the laminates with the mandrel, and cooling and contracting the material substantially at the outer surface of the stator to impart a positive inward force to the laminates. The method includes the step of aligning the laminates against each other and against the mandrel in a fixed position relative to the rotor axis, the method of manufacturing including the step of aligning the laminates against each other and in a fixed position relative to the rotor axis to form a continuous layer surrounding the stator component. The method also includes introducing a thermoplastic material into the interior of the stator component and surrounding the interior of the stator. Next, the structure and manufacturing method of a preferred configuration example of the present invention will be explained.

1 to 5, the stator 18 for the limited rotary galvanometer is of laminated construction with its shaft 44 and end plates 24, 28 (see FIGS. 2 and 3, respectively).
A hard thermoplastic outer layer 19 is molded around it (see figure).

The pole piece assembly 20 is formed from a number of identical thin laminate pieces 22 stacked vertically with die cast aluminum plates 24 and 28 at the bottom and top, respectively. The assembly is held together by aluminum rivets passing through holes in the laminates and end plates. A winding 34 is wound around the assembly in a recess 36 on each side of the long end of the assembly, and two permanent magnets 38 are arranged between the assemblies in a recess 40 on the other side. A generally cylindrical depression is formed in the center of the stator 18 by the various components described above. The outer layer 19 is injection molded nylon that is 35% glass filled and shrinks and solidifies by more than 1% (approximately 3%) upon cooling.

This layer should be at least 20,000 pounds per square inch (P
si) (approximately 1400 kg/d) and 5000 ps for a duration of 104 hours at room temperature.
i (has a creep rate of about 350 kg/(V7F)).
The bending tensile strength of this material is 12000 ps at room temperature.
i (approximately 840 kg/C7l). Plate 24 has a groove 46 with a resin flow space between the plate and magnet 38.

The injection molded material fills the groove 4 between the magnet 38 and the plate 24.
6 and other openings not shown to fill the interior space within the stator and also surround the windings and magnets as indicated by 36a and 48a in FIG.

An annular collar 50, which serves to seat the torsion bar attached to the rotor 52 during final assembly, is molded into and secured by the material (see FIG. 4). (The function of the torsion bar is described in the inventor's US Pat. No. 3,624,574.

The molded hard outer layer 19 is under circumferential tension in the direction indicated by lines x and y and arrows in FIG. 5 as a result of solidification and shrinkage upon cooling from molding. The circumferential tension is transferred to the laminate 22 and serves to press it together with the magnet (see compression arrow A in FIG. 2) and also against each other, making it under prestressed conditions producing excellent hysteresis-free operation. Fix it so that it does not move. 6 to 9 show another embodiment in which the layer 19' is shaped only in the direction around the axis 44' and the collar 50' is integral with the plate 28'. There is.

The exposed end plate 24' of the molded assembly is clamped against the metal mounting middle plate 51. This configuration allows unimpeded heat flow from the interior of the galvanometer to the mounting plate, which acts as a heat dissipator. A limited rotation rotor 52' is shown assembled with a stator in these figures and drives a mirror 53' as an optical scanner. Other parts corresponding to the parts in the first configuration example correspond to prime C)
It is indicated by a number. An alternative arrangement using sintered metal pole pieces instead of laminated pieces is illustrated in FIGS. 9 and 10. Stator 100 is made of 50% nickel and 50% iron.
070 in the form of two 1 inch (approximately 2.54 CTrL) high pole pieces 102. Each pole piece has a recess 104 for the winding and a pole face 106 defining a cylindrical rotor space. A magnet 114 is located between the pole pieces 102 . A vertical groove 105 is formed on the outer surface of the pole piece 102 . The pole pieces are located between plates 108 and 110 by aluminum pins 112 which are fixed to the plates and which are in grooves 105 and engage opposite surfaces thereof. are doing. A hard thermoplastic outer layer 19' is molded around the stator as described above for laminated stators.
A configuration example having the characteristics of the improved connector of the present invention is the first example.
It is illustrated in FIGS. 5 to 20.

Galvanometer 218 is surrounded by a hard thermoplastic outer layer 219 and is generally attached to a pole piece assembly 220 as in the previous configuration.
, drive winding 234, pick-off winding 234', magnet 23
8 and a rotor 252. The windings are connected to circuitry on the printed wiring board and male connector pins 262 that are electrically connected to the circuitry. board 260
is completely surrounded by layer 219 and has a centering hole 261 surrounding rotor 252 . Pin 262 is soldered to plate 260 and bent at right angles so that it passes through layer 219 and is exposed in recess 264. A detent member 266 in the form of a molded cantilever spring extends integrally from its root in layer 219 to form one wall of recess 264. An external plug 270 for connecting the galvanometer to an external circuit is configured to fit into the recess 264 and has a recessed female connector 224 that engages the pin 262.

As plug 270 is inserted into the recess, member 266 is deflected slightly upwardly against plug 270, but returns to its original position when ridges 268 on the detent member engage corresponding grooves 272 in plug 270. lock in the correct position. Metal collar 250 of FIGS. 15 and 18 is generally annular and includes an integral tongue 251 extending through layer 219 to outer wall 217. Metal collar 250 of FIGS.

Collar 250 and tongue 251 are integral with plate 210. Hole 274 passes through tongue 251 and collar 250. This hole receives a set screw 276 that secures a torsion bar bushing 278 to one end of a torsion bar 280. No. 5 of Inventor's U.S. Pat. No. 3,624,574
As shown in the figure, the torsion bar 1 (2 in the figure)
0') is fixed to one end of the rotor (12' in the drawing). Layer 219 is shaped to be substantially flush with the end surface of collar 250. Manufacturing of the laminated stator is carried out by aligning the laminated pieces 22 with a temporary jig. The magnets 38 are temporarily secured to the assembly and the stator parts are tightened in place between the end plates. Four holes 32 in the end plates and laminates receive rivets 30. The peening process on the reppet compresses the rivet to close the hole and tighten the assembly, but this is not sufficient to be satisfactory for galvanometer operation. With the stator component in position relative to the central axle 80 (FIGS. 11-14), the mold is closed around the component.

The mold has a bottom plate 82 to which a fixed mandrel 80, a positioning rod 84, and a take-out pin 86 are fixed. The central portion 88 of the mold has a hole 85 through which a rod 84 extends. The stator parts of FIGS. 1-4 are placed in the mold and spaced apart from the bottom of the central section 88 by pins 86, which also allow the layer 19 to connect the screw mounting holes 23 in the plate 24. It helps to keep it uncovered. (The stator end plates 24' in the configuration examples of FIGS. 6 to 9 engage with corresponding molding surfaces,
It is therefore kept free of injection molding materials. ) Molten thermoplastic material is introduced through a port 92 in the top molding piece 90 and immediately flows into a cavity 93 around the exterior of the stator.

This material then flows through the space between the magnet 38 and the groove 46 to reach the interior and form the enclosure 48a. Material also flows through the end space 49 and around the winding 34 to surround the internal winding at 36a. Such inward flow occurs after the material has filled around the outer surface of the stator. Because it enters the interior space late and also has a large exterior surface area, the molten plastic layer tends to hold the magnet in place without forcing it outwardly from the recess in the stator piece. As the outer layer cools, solidifies and contracts, the resulting circumferential stress exerts a net inward force on the laminate. As indicated by compression arrow A in FIG. stabilize. Ejection pins 86 allow gas to escape and serve to remove the stator from the mold.

Another example of a configuration using a shaped sintered metal pole piece with a shaped groove 105 is a pin 11 that engages the groove 105.
2 by aligning and fixing the sintered pieces between plates 108 and 110. There is no need to drill through holes in the plate, nor do holes need to be provided in the laminate. Although the retention device alone will not be sufficient to secure the laminate during operation of the galvanometer, the continuous outer layer 119 of hard thermoplastic material, when molded as described above, will hold the laminate in place. applying an inward force to press the laminate pieces together with the magnet under prestressed conditions in such a way as to maintain the operating force without separation or adverse hysteresis, It also stabilizes in a fixed position relative to the shaft. For other configurations, the stator component is configured to positively engage the corresponding face of the magnet before it reaches the mandrel, ensuring high voltage contact between the pole piece and the magnet. . If it is desired to mold the material only around the axis of the stator, as is the case in the configurations of FIGS. 6-9, molding pieces 82, 88 and 90
are designed to prevent flow onto the metal end plate 24.

This leaves the end plate exposed and allows heat to be transferred away to the adjacent surface to cool the galvanometer. The fabrication of the example configuration of FIG. 15 is illustrated in FIGS. 18 and 19.

Pins 262 are soldered to printed wiring board 260 and the stator assembly is placed in a mold around mandrel 80'. A metal molded plug body 282 attached to the mold wall 88' by two rods 284 is attached to the pin 262.
to prevent flowing thermoplastic material from covering it and to position and support pins and wiring boards during molding. The molten thermoplastic material enters the gap around plate 260 and the exposed portion of pin 262 through port 92' and, upon cooling, supports and insulates them. A cantilever detent 266 is formed in the gap between the mold 90' and the plug body 282. A ridge 268 is formed by the recess 286. After molding, the plug body 282 is removed and the pin 2
A portion of 62 is exposed. Because the tongue 251 extends to the mold wall, it has an exposed surface in the finished product, so there is no need to drill holes in the layer 219 to attach the set screw 276. Various modifications are possible within the scope of the invention.

For example, additional shaped sintered pieces can be stacked around the rotor to provide a greater height, preferably less than 3 inches (about 7.60!n).
The layer can be reinforced with other materials, including but not limited to carbon.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the stator in a first preferred configuration with flexible electrical leads projecting through the molding layer; FIG. 2 is a perspective view taken along line 2--2 of FIG. FIG. 3 is a horizontal cross-sectional view of the cut stator, shown at 3-- in FIG. 2.
Figure 4 is a vertical sectional view taken along line 3.
5, which is a vertical cross-sectional view taken along line 4-4 in the figure.
FIG. 6 is a schematic perspective view of the stator laminates and magnets under circumferential tension; FIG. 6 is a perspective view of another configuration example with the sides of the layers partially cut away; FIG. 8 and 9, which are bottom views of the configuration example shown in FIG. 6, are vertical sectional views taken along lines 8-8 and 9-9 in FIG.
0 is an exploded perspective view of a preferred stator formed from a piece of sintered metal; FIG. 11 is a cross-sectional view of the stator of FIG. 10 with a mold; and FIG. 12 is a fixation in the mold. FIG. 13 is a plan view of the mold and stator, FIG. 14 is a perspective view of the mold and stator, and FIG. 15 is a side sectional view of the molded material. 16 is a perspective view of a preferred configuration with an enclosed printed wiring board and connector pins; FIG. 16 is a vertical cross-sectional view of a portion of the configuration of FIG. 15 during molding; FIG. 18 is a vertical sectional view taken along line 18-18 in FIG. 15; FIG. 19 is a vertical cross-sectional view taken along line 19-19 in FIG. 15. FIG. 20, which is a sectional view, is an exploded perspective view showing parts of the configuration example of FIG. 15. In these figures, 18 is a stator, 19 is a thermoplastic outer layer, 22 is a laminate, 24 and 28 are end plates, 30 is an aluminum rivet, 26 is a printed circuit board, 38 is a magnet, and 52 is a rotor. , 100 is a stator, 102 is a magnetic pole piece,
105 is a vertical groove, 108 and 110 are plates, 112 is an aluminum pin, 224 is a female connector, 250 is a metal collar, 251 is a tongue, 262 is a male connector pin,
266 is a detent member, 270 is an external plug, 276
indicates a set screw.

Claims (1)

[Scope of Claims] 1. A stator part having juxtaposed parts comprising a permanent magnet and at least one pole piece, and a stator part mounted for rotation relative to said stator part on an axis. A limited rotary galvanometer comprising a rotor and a continuous outer layer of synthetic resin material extending around said stator component, said rotor being a movable iron rotor, and said rotor being a movable iron rotor; The material is a reinforced thermoplastic material with a shrinkage of at least 1 percent when cooled from the molding temperature, said continuous resin layer having a ring shape subject to circumferential tension resulting from shrinkage and solidification after molding. a member, said shaped ring-shaped member exerting a compressive stress on said stator part so as to force said magnets and said pole pieces against each other with a preload, thereby controlling the motion of said ferrous rotor. said limited rotation type, characterized in that said preload prevents movement within said stator parts and the occurrence of a corresponding detrimental hysteresis, improving the accuracy of the deflection of the galvanometer pointer. Galvanometer. 2 Mechanical retaining devices which alone cannot adequately hold said stator parts in the correct position during operation of the galvanometer.
For example, the stator parts are held by 24, 28, 30) in FIG. A galvanometer according to claim 1, characterized in that the galvanometer is embedded in a layer. 3 a stator part having juxtaposed parts comprising a permanent magnet and at least one pole piece; a rotor mounted for rotation relative to said stator part on an axis; a continuous outer layer of synthetic resin material extending around a child part; the synthetic resin material is reinforced and has a shrinkage rate of at least 1 percent when cooled from the molding temperature; and cooling and solidifying the material. said cooling, solidifying and shrinking step, said continuous synthetic resin layer comprising a ring-shaped member subjected to circumferential tension resulting from said shrinking and solidifying after molding; and further characterized in that the molded ring-shaped member exerts a compressive stress on the stator component so that the magnet and the pole piece press against each other with a preload, and the rotation the child is a moving iron rotor, said preload prevents movement within said stator parts and the creation of a corresponding harmful hysteresis;
The method for manufacturing the limited rotation type galvanometer described above, characterized by improving the accuracy of the deflection of the pointer of the galvanometer. 4. Providing said stator part in the form of a shaped sintered metal piece with a molded outer surface retainable formation, which alone cannot secure said metal piece during operation of the galvanometer; holding said metal piece in said grippable formation by a mechanical holding device, said injection molding step including embedding said holding device in said synthetic resin layer; 3. The limitation of claim 3, wherein said cooling step creates said circumferential tension to fix said metal piece against movement relative to said rotor axis. Manufacturing method of rotary galvanometer.