CN86102500A - Electric variable speed and control transmission - Google Patents

Abstract

An electrically variable and controlled transmission, particularly for industrial sewing machines, includes a continuously operable motor with a flywheel and a brake-coupling element connected to the motor. The cooling ribs define cooling channels on the stator frame for effective cooling. A fan of the circular flywheel type is an axial-radial blower whose suction zone extends as far as the coupling surface of the circular flywheel. A particularly strong cooling effect can thus be given to the brake end cap.

Description

Electric speed change and control transmission

The present invention relates to an electric speed changing and controlling transmission device which is particularly suitable for industrial sewing machines.

Refer to U.S. Patent No. 4,556,132 for a transmission of this type. This transmission has an annular cooling channel surrounding the stator frame, through which air is drawn by a fan-shaped circular flywheel. Cooling channels are also located radially outside the circular flywheel, through which air is drawn in and out as the flywheel rotates. The air is primarily discharged axially, flowing between cooling ribs fixed to the outer periphery of the brake end shield. This does not guarantee satisfactory cooling, especially in the case of a circular flywheel subject to high thermal stresses.

An object of the present invention is to provide a speed-changing and control transmission particularly suitable for use in industrial sewing machines which ensures satisfactory cooling of the motor and coupling and braking components.

According to the present invention, a significant amount of the heat generated by the motor is dissipated into the cooling air flowing between the cooling fins fixed to the stator frame, significantly reducing the temperature of the housing (where seamstresses particularly dislike high temperatures). Because the air flows essentially along the straight lines extending from the cooling channels defined by the fins, there is minimal air turbulence and low resulting noise. Since the fan suction area of the axial-radial blower extends almost to the coupling surface, excellent cooling is ensured in this critical area.

And fan provided by the invention has enough suction capacity, simultaneously, allows cooling air to enter in the radial fan of the circular flywheel of high thermal stress and go in a very large part.Just can obtain providing radial passage of high suction capacity and high cooling capacity with a simple construction form.

Furthermore, the present invention changes the direction of the air exhausted from the radial passages formed in the circular flywheel and merges it with the air flow for cooling the outer periphery of the brake end cover.

Cooling at the brake end cap is further enhanced. Furthermore, the present invention provides particularly strong cooling of the outer side of the brake end cap while also facilitating the early removal of some of the hot air, potentially containing lint, drawn through the air duct. Furthermore, thanks to the circular flywheel, the present invention facilitates directing the cooling air at the brake end cap to areas of high thermal stress on the brake components. Furthermore, the present invention facilitates dissipating heat generated at the coupling coil or brake coil into the cooling air along this direct path.

Furthermore, the present invention further reduces the heat dissipated by the housing surrounding the stator frame.

According to the present invention, an electric speed change and control transmission device, particularly suitable for use in industrial sewing machines, includes a continuously rotatable motor, a flywheel having a clutch surface and connected to the motor, and a clutch-brake assembly connected to the motor. The transmission device also includes a drive shaft. The clutch-brake assembly includes a clutch brake disc non-rotatably connected to the drive shaft. The clutch-brake assembly also includes a non-rotatable brake support bracket with a brake surface. The clutch-brake disc can selectively frictionally engage with the brake surface of the brake support bracket or with the clutch surface of the flywheel. The motor includes a stator frame and an outer housing defining a cooling region surrounding the stator frame. The flywheel forms a fan for drawing in cooling air. Cooling channels defined by cooling fins are located on the stator frame, and the fan is an axial-radial blower having a suction region extending proximate the clutch surface.

For a better understanding of the present invention and its objects, please refer to the following description and drawings, and the scope of the present invention will be set forth in the appended claims.

Now please refer to the attached figure:

Figure 1 shows a longitudinal sectional view of the shaft of the transmission device according to the present invention comprising a motor and a brake - coupling member;

Figure 2 shows the brake in Figure 1 - an enlarged view of the coupling member;

Figure 3 shows a portion cut from the brake - coupling member;

FIG. 4 shows another section cut from the brake coupling component.

The transmission device shown in the figures includes a motor 1 and a brake-clutch assembly. Motor 1 preferably comprises a generally cylindrical stator frame 3, on which a stator coil 4 and a layered coil 5 are conventionally located centrally. A rotor 7 is also mounted centrally on a central longitudinal axis 6. The rotor is connected to a motor shaft 8, which rotates on bearings located on end caps 9 and 10. The end cap 10, remote from the brake-clutch assembly 2 (brake-clutch assembly), is preferably cast integrally with the stator frame 3. The motor shaft rotates in a bearing located in a bearing bore 11. This bearing is preferably a rolling bearing assembly 12, which is a radial-axial ball bearing. The inner ring 13 of the rolling bearing 12 is supported on a collar 14 on the motor shaft 8. On the other axial side, the outer ring 15 of the rolling bearing 12 is supported on a stop ring 17 via a prestressed helical compression spring 16. The stop ring is preferably cast as one piece with the end cover 10. In this way, on the one hand, it can be ensured that the rolling bearing 12 does not move axially on the motor shaft 8, and on the other hand, the axial position of the motor shaft 8 can be adjusted within the allowable adjustment range of the spring 16.

The end cap 9 is preferably integrally cast with the generally cylindrical housing 18 and connected to the stator frame 3 by connecting screws 20 via centering pins 19, positioned along the centerline of the shaft 6. The motor shaft 8 is also preferably supported in a bearing bore 21 in the end cap 9 by a rolling bearing 22, which is a radial-axial ball bearing. The inner ring 23 of the rolling bearing 22 preferably rests on a collar 24 on the motor shaft 8, while the outer ring 25 of the rolling bearing 22 is preferably supported on the other side, that is, the side facing the component 2, and is abutted against a locking ring 27 fixed in the bearing bore by a prestressed helical compression spring 26. This ring performs the same supporting function as the retaining ring 17 on the end cap 10. The spring 26 serves to load the outer ring 25 of the rolling bearing 22 in the bearing direction, thereby suppressing any noise generated there. If the outer ring of the rolling bearing is not resting against anything, it will vibrate and generate noise. The tension of the spring 26 must be significantly less than that of the spring 16 to avoid counteracting the latter's effect.

A circular flywheel 29 is preferably fixed in a torsionally fixed manner to the extension shaft 28 of the motor shaft 8 by means of a tongue-and-groove connection 30 and is equipped with a rolling bearing 22. The free front end of the hub 31 of the circular flywheel 29 preferably rests against the inner ring 23 of the rolling bearing 22 and is preferably pressed axially against the inner ring 23 by means of a nut 33 which is screwed onto the threaded rod 32 of the extension shaft 28 and is simultaneously fixed axially in position relative to the motor shaft 8. The portion of the motor shaft 8 comprising the rotor 7, the rolling bearings 12, 22, and the circular flywheel can be displaced along the central longitudinal axis 6, with springs 16 and 26 acting in the direction of displacement, respectively, exerting opposing forces.

The outer temple 18 is covered on the side remote from the motor 1 by a brake end cover 34 (brake bearing bracket), which is preferably fixed in the center position of the housing 18 and coaxial with the axis 6 by a centering collar 35. The brake end cover 34 is preferably fastened to a suitable flange 37 of the housing by screws 36.

The drive shaft 38, coaxially positioned with the central longitudinal axis 6, preferably rotates on fully rotatable bearings, one in a bearing hole 39 in the brake end 34 and the other in a bearing hole 40 in the circular flywheel 29 opposite the latter. The drive shaft 38 preferably rotates on rolling bearings 41 and 42, which are radial-axial ball bearings located in the bearing holes 39 and 40, respectively. A coupling-brake disk 43 (clutch-brake disk) is preferably mounted on the drive shaft 38 between the rolling bearings 41 and 42. This coupling-brake disk preferably includes an outer pivot ring 44 made of a magnetic material. A spring washer 45 is preferably secured to the outer edge of this pivot ring 44 by screws 47. The spring washer 45 is preferably secured to an annular collar 48 protruding radially from the drive shaft 38 by screws 47 in the area of the inner edge of the pivot ring 44. This fixing method using a thin spring washer 45 allows the pivot ring 44 to move along the axis 6 and remain coaxial with it.

An annular friction pad, serving as a coupling surface 49 (clutch surface), is preferably fixed to the side of the pivot ring 44 facing the circular flywheel 29. This pad is intended to mate with an annular linear coupling surface 50 (clutch surface) on the front side of the facing circular flywheel 29. The pivot ring 44 preferably has a ring member 51 on its outer periphery, extending axially toward the circular flywheel 29. This ring member 51 preferably extends to the circular flywheel 29 with only a small axial clearance a of a few tenths of a millimeter. The outer periphery of the annular coupling surface 49 (clutch surface) substantially abuts the inner periphery of the ring member 51.

The brake end cap 34 includes a coupling coil housing 52 (clutch coil housing). This housing preferably surrounds the pivot ring 44, leaving only a small radial gap b of a few tenths of a millimeter. Preferably, a radially outer ring member 53 of the housing surrounds a radial peripheral portion 54 of the circular flywheel 29 adjacent to the coupling surface 50, leaving only a radial gap c of a few tenths of a millimeter. An annular electromagnetic coupling coil 51 (clutch coil) is preferably mounted within the coupling coil housing 52, which is partially fixed to the brake end cap 34. When the coupling coil 51 is energized, a magnetic circuit 56 flows from the coupling coil housing 52 through the housing member 53, closing the radial gap c, the peripheral portion 54 of the circular flywheel 29, the circular flywheel 29, the axial gap a, the ring member 51 of the pivot ring 44, and the radial gap b, returning to the coupling coil housing 52. This causes the coupling surface 49 of the coupling-brake disc 43 to press against the coupling surface 50 of the circular flywheel 29, thereby coupling the motor shaft 8 to the transmission shaft 38 as the circular flywheel 29 rotates.

The pivot ring 44 is preferably equipped with a friction pad serving as a brake pad 57 on the side facing away from the circular flywheel 29. This brake pad is preferably secured to the pivot ring 44 by adhesion or a similar fixing method. An annular linear brake surface 58 on the brake end cap 34 engages with the friction pad. The coupling surface 49 is preferably fixed to one side of the frame 44, along with the spring washer 45. The annular brake pad 57 is preferably seated in a suitably mating annular recessed surface 59 on the frame 44. The pivot ring, preferably made of a magnetic material, extends radially inward from the recessed surface 59 to the vicinity of the annular collar 48, creating an annular linear magnetic transmission surface 60 on the pivot ring 44. This surface 60 faces a brake coil housing surface 61 radially inward of and aligned with the brake surface 58, preferably leaving an axial gap d of approximately a few tenths of a millimeter between them. A brake coil housing 62 is preferably provided on the brake end cap 34. The front of the brake coil housing is preferably covered by the brake coil housing surface 61. An annular brake coil 63 is preferably arranged in this brake coil housing 62 in such a manner that, on the one hand, magnetic flux can be transported radially within the brake coil 63 and radially outside the brake coil 63, but always within the brake pad 57. When the brake coil is energized, a brake magnetic circuit 64 is generated, wherein one magnetic circuit 64a extends radially out of the brake coil 63, passes through the brake coil housing 62, the axial gap d between the brake coil housing surface 61 and the magnetic transmission surface 60 (in each case, between the brake pad 57 and the brake coil 63), passes through the pivot ring (here radially pointing toward the center), and returns to the brake coil housing 62 through the axial gap d radially inside the brake coil 63. Another path 640 of the brake magnetic circuit 64 radially penetrates the coupling coil housing 52, passes through the radial gap b, radially passes through the pivot ring 44 and points toward the center, where the two paths 64a and 64b meet again.

As shown in FIG3 , the coupling coil housing 52 preferably includes an axial-radial undercut located in the area of the ring 51 facing the brake pad 57. This undercut preferably extends to a depth such that the ring 51 extends approximately one millimeter into the undercut, toward the brake end cap. The radial and axial distances of this undercut from the nearest area of the ring 51 are preferably greater than 0.5 mm, and even greater than 1 mm. This allows a radial magnetic path from the coupling coil housing 52 to pass through the radial gap b. Consequently, when the coupling coil 55 is energized, the possibility of the ring 51 on the frame 44 "sticking" to the brake end cap 34 is eliminated.

The coupling magnetic circuit 56 preferably passes only approximately axially through the axial gap a, thereby generating an appropriate coupling force in this area. Alternatively, the coupling magnetic circuit 56 may also pass only axially through the radial gap c between the peripheral portion 54 of the circular flywheel 29 and the shell 53 of the coupling coil housing 52. This allows a displacement force to be applied to the component consisting of the rotor 7, motor shaft 8, and circular flywheel 29, causing it to move axially against the spring forces of springs 16 and 26. This is achieved by an additional recess. A recess 66 on the coupling coil housing 52 preferably extends radially outward so that the peripheral portion 54 of the circular flywheel 29 can axially extend into the recess by approximately 0.5 to 1 mm.

Another recess 67 is preferably provided on the circular flywheel 29. This constrains the cylindrical peripheral portion 54 on the side facing away from the coupling-brake disc 43. The housing member 53 preferably extends axially into this recess 67. The minimal displacement of the peripheral portion 54 relative to the coupling-brake disc ensures that when the coupling coil 55 is energized, no force is exerted on the circular flywheel 29 in the direction of the coupling-brake coil 43. Instead, a very small force is exerted in the opposite direction on the circular flywheel 29. This ensures that when the coupling coil 55 is energized, the circular flywheel 29 does not move in the direction of the coupling-brake disc 43. The coupling coil 55 and the brake coil 63 are preferably connected in such a way that the coupling magnetic path 56 and the brake magnetic path 64b run in opposite directions in the region of the coupling coil housing 52 through which they pass. This results in a more rapid dissipation of the magnetic flux and a more rapid movement of the coupling-brake disc from its position on the circular flywheel 29 to its position on the brake support 34, and vice versa. As can be seen from FIG2 , the width of the air gap between the coupling surface 49 and the coupling surface 50 is preferably about 0.1 to 0.2 mm. That is, when switching from the braking state to the coupled state and vice versa, the pivot ring 44 with the brake pad 57 and the coupling surface 49 only needs to move a very short distance in both cases. FIG3 shows an enlarged view of the air gap 68 between the brake pad 57 and the brake surface 58 during coupling.

The inner ring 69 of the rolling bearing 41 supported on the brake end cap is preferably supported on a stop collar 70 on the drive shaft 38 on the side facing the circular flywheel 29. The outwardly facing outer ring 71 of this rolling bearing 41 preferably rests on an adjusting nut 72, which is screwed into an external thread 73 around the bearing hole 39 in the brake end cap 34. The adjusting nut 72 is preferably fixed in position relative to the brake end cap by a set screw 74. During displacement from the brake coupling 2, the position of the drive shaft 38 is securely fixed by the adjusting nut 72 and the bearing seat of the rolling bearing 41.

The side of the inner ring 75 (the inner ring 75 of the rolling bearing supported in the circular flywheel 29) facing the coupling-brake disk 43 preferably rests on a stop 76 fixed to the drive shaft 38, which stop is formed by a locking ring, and the side of the inner ring 75 facing the motor 1 is a free surface.

The side of the outer ring 77 of the rolling bearing 42 that faces the coupling-brake disc 43 is a free surface. The side of the outer ring 77 that faces the motor 1 preferably rests on a fixed sleeve 78 mounted in the bearing bore 40. The fixed sleeve 78 preferably has a narrow slot 79 into which a tenon 80 of a safety plate 81 secured by the nut 33 extends, thereby securing the fixed sleeve 78 against the circular flywheel 29 by torsion. The drive shaft 38 preferably has a continuous hole 82 through which an adjustment screw 83 is threaded into a threaded hole 84 in the shaft extension 28. This adjustment screw can be adjusted using a screwdriver or similar tool. Adjusting the adjustment screw 83 in this manner effectively adjusts the axial position of the adjustment screw, or more specifically, the axial position of the adjustment screw relative to the motor shaft and, therefore, the circular flywheel 29, due to the radially outwardly projecting stop ring 85 attached to the adjustment screw. One of the bimetallic discs on the adjustment screw 83 is preferably supported on the stop ring 85. The outer edge of the opposing disc (i.e., the outer edge of the bimetallic disc closest to the coupling-brake disc 43) preferably rests on an annular edge 87 of the fixing sleeve 78. The axial position of the circular flywheel 29 relative to the drive shaft 38 can be varied by adjusting the shaft extension 28 by screwing it in and out. Because the compression spring 16 continuously presses the motor shaft 8 together with the circular flywheel 29 toward the coupling-brake disc 43, the static pressure of the coupling-brake disc 43 with the brake pads 57 can be adjusted by adjusting the adjusting nut 72 in the rear area of the brake end cap 34. This also adjusts the air gap 68 between the coupling surface 49 and the coupling surface 50. When neither the coupling coil 55 nor the brake coil 63 is energized, the coupling-brake disc 43 preferably rests against the brake surface 58 of the brake end cap 34 with an adjustable initial pressure. If the coupling surface 49 and the brake pads 57 expand due to thermal loads from frequent switching, this will also cause the circular flywheel 29 to heat up accordingly. This heat is transferred to the bimetallic discs 86, causing them to bend, causing the discs to bend and press against each other according to their arrangement. This causes the adjustment screw 83, along with the motor shaft 8 and circular flywheel 29, to move toward the motor 1 against the tension of the spring 16. This compensates for the reduction in air gap 68 caused by the thermal expansion of the coupling surface and brake pad 57. This compensation is necessary because the air gap width should typically be 0.1 mm to prevent creaking noise when connecting the coupling-brake disc 43. However, this tiny air gap must be precisely maintained during operation and must not be allowed to decrease.

As shown in FIG1 , cooling fins 98 are preferably mounted on the stator frame 3 . These fins are preferably distributed over the stator frame area and extend radially parallel to the axis 6 . A cup-shaped cover 99 enclosing the cooling fins 98 is preferably pushed over the entire stator frame 3 . The faceplate 100 of the cover 99 preferably rests on spacers 101 , which are preferably cast integrally with the end cap 10 . The cover 99 is preferably secured to the spacers 101 by screws 102 . The faceplate 100 of the cover 99 preferably has openings to allow cooling air to enter. The generally cylindrical housing 104 of the cover 99 preferably rests on projections 105 on the cooling fins 98 , making only point-to-point contact with the cover 99 . Heat conduction is from the stator frame 3 through the cooling fins 98 to the cover 99 , resulting in minimal heat generation and minimal temperature rise in the cover 99 .

Cooling ribs 106 corresponding to cooling ribs 98 are preferably also mounted in housing 18. They preferably extend partially radially between end shield 9 and housing 18, so that they also support the end shield. A free space 107 is preferably provided between circular flywheel 29 of end shield 9, and cooling channels 108 formed between ribs 98 and stator frame 3 or housing 104 of cover 99, or between cooling ribs 106, end shield 9, and housing 18, communicate with this free space.

The circular flywheel 29 preferably has a suction area 109 on the side facing the motor 1. This suction area is preferably an annular space and communicates with the free space 107 surrounding the hub 31 of the circular flywheel 29. Radial channels preferably extend outward from this suction area 109. These channels are defined by axially and radially extending fins 111, which are preferably cast integrally with the circular flywheel. An annular air guide ring 112 is preferably fixed to the side of the fins 11 facing away from the circular flywheel by screws 113. This ring defines radial channels extending to the motor 1. The fan formed in this way is an axial-radial blower.

The cooling air drawn through the openings passes through the cooling passages 108, through the free space 107, through the suction zone 109, and then through the radial passages 110 in the direction indicated by arrows 114. As shown in FIG1 , since the suction zone 109 extends to the vicinity of the coupling surface 50, very effective cooling efficiency is provided to the critical light area of the coupling surface 50.

Air flows out through radial passages 110 between cooling fins 115 located on the outer periphery and front of the brake end cap 34. An annular sheet metal cover 117 is preferably secured to the exterior of the front side of the brake end cap 34 using screws 116. This allows a portion of the air flowing between the cooling fins 115 to change direction, flowing radially inward, as indicated by arrows 118, cooling the front surface of the brake end cap 34. The brake end cap 34 preferably includes an annular groove serving as a swirl chamber near the braking surface 58 of the brake end cap 34 and radially between the coupling coil 55 and the brake coil 63. This groove extends to the vicinity of the coupling coil 55, the brake coil 63, and the braking surface 58. Within this chamber, air swirls in the direction indicated by arrows 118 before being discharged through an outlet 120 located radially inward of the sheet metal cover 117 near the adjusting nut 72.

Redirecting the cooling air flowing out of the radial channel 10 into an air flow rolling between the cooling fins 115 and parallel to the axis 6 is preferably carried out in a redirecting guide area 121, the outer side of which is defined by the housing 18.

Although the preferred embodiment of the present invention has been described, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention. It is therefore intended that all such changes and modifications be included within the spirit and scope of the present invention.

Claims (9)

1, a kind of electric shift that industrial sewing machine uses and transmission device of control of being specially adapted to, it comprises: the motor of an energy Continuous Drive, one has clutch surfaces and is connected to flywheel on the said motor, a clutch-brake component that is connected on the said motor, a power transmission shaft, above-mentioned clutch-brake component comprises a clutch-brake disc, this dish is connected on the above-mentioned power transmission shaft without spin, above-mentioned clutch-brake component also comprises the braking frame support bracket with a brake area, above-mentioned clutch-brake disc can selectively be made friction engagement with the above-mentioned brake area of above-mentioned braking frame support bracket or with the above-mentioned clutch surfaces of above-mentioned flywheel, said motor has a rotor frame and by around the shell that cooled region limited of said stator framework, above-mentioned flywheel has formed the fan of a suction cooling air, cooling fin on the said stator framework defines the cooling duct, said fans be a kind of axially-air blast of radial mode, air blast has the suction district of an extension near above-mentioned clutch surfaces.

2, the device that requires according to claim 1, the above-mentioned suction district of a transmission device includes a ring groove and a radial passage of drawing with above-mentioned groove on above-mentioned flywheel.

3, the device that requires according to claim 2, transmission device are included in the fin on the above-mentioned flywheel and are installed in a air guide ring on the flywheel, and above-mentioned radial passage is exactly determined by above-mentioned fin on the above-mentioned flywheel and above-mentioned air guide ring.

4, the device that requires according to claim 2, a transmission device comprises a guidance field of guiding again in the back, above-mentioned radial passage of above-mentioned flywheel, and the outer surface of above-mentioned braking frame support bracket has cooling fin, and these fins and above-mentioned guidance field join.

5, the device that requires according to claim 4, the above-mentioned cooling fin of a transmission device on above-mentioned braking frame support bracket extends to the front of above-mentioned braking frame support bracket always.

6, the device that requires according to claim 5, a transmission device comprises a metallic plate lid, the above-mentioned cooling fin that extends to above-mentioned braking frame support bracket front has at least a part to be covered in by above-mentioned metallic plate lid.

7, the device that requires according to claim 6, a transmission device has a groove in the above-mentioned front of above-mentioned braking frame support bracket, and this groove extends near the above-mentioned brake area always.

8, the device that requires according to claim 7, a transmission device comprises a clutch coil and a restraining coil on above-mentioned braking frame support bracket, and the groove in the above-mentioned front of above-mentioned braking frame support bracket extends to the above-mentioned clutch coil on above-mentioned braking frame support bracket and the zone of above-mentioned restraining coil always.

9, the device that requires according to claim 1, a transmission device only has sub-fraction to lean on above-mentioned shell at the above-mentioned cooling fin on the rotor frame.

Images