JP4696536B2 - Varnish impregnation apparatus and varnish impregnation method - Google Patents

Description

  The present invention relates to a varnish impregnation apparatus and a varnish impregnation method for dripping and impregnating varnish into a winding coil inserted and disposed in a stator core.

For example, in a motor stator used in a vehicle or the like, a varnish is dropped on a winding coil inserted and disposed in a slot of a stator core so that the electric insulation, vibration resistance, oil resistance, Improved chemical properties and heat dissipation.
For example, in the method of dripping and impregnating a varnish disclosed in Patent Document 1, a stator core having a winding coil inserted therein is held so that its axial direction is a horizontal direction. And while rotating this stator core, varnish is dripped at the coil end part which a part of winding coil protrudes from the axial direction edge part of a stator core.

  As a result, the varnish dripped onto the coil end part is permeated by capillary action into the insertion arrangement part where the remaining part of the winding coil is inserted and arranged in the slot of the stator core, and the entire winding coil is impregnated with the varnish. I am letting. Further, by performing the above-described dripping impregnation, varnish is prevented from adhering to portions other than the slots, insulating paper, and winding coils in the stator core, that is, the axial end, outer peripheral portion, and inner peripheral portion of the stator core.

  However, in the varnish impregnation method of Patent Document 1, the varnish dripping impregnation is performed in an atmospheric pressure state. For this reason, air remains at atmospheric pressure between the winding coil insertion portion and the slot, and the permeation rate of the varnish decreases, and in some cases, the varnish penetrates the entire winding coil uniformly. I can't let you. This makes it difficult to shorten the varnish impregnation time and to improve the varnish impregnation rate.

In the varnish impregnation method of Patent Document 2, the stator (rotor) is housed in a bag having airtightness and flexibility, the inside of the bag is brought into a vacuum pressure state, and the varnish is injected into the bag. A method of impregnating the varnish by rotating the stator together with the bag is disclosed.
However, in this varnish impregnation method, the stator is rotated while immersing a part of the stator in the varnish, and the entire stator including the stator core is impregnated with the varnish. For this reason, the varnish adheres to a portion that does not need to be impregnated with the varnish.

  Moreover, the varnish impregnation method of patent document 2 forms a vacuum pressure state once, performs impregnation of a varnish, returns to an atmospheric pressure state, and is further impregnated with a varnish. Therefore, it has not been sufficient to shorten the impregnation time of the varnish in the winding coil in the stator and improve the impregnation rate of the varnish.

JP 2003-189523 A Japanese Patent Laid-Open No. 11-41878

  The present invention has been made in view of such conventional problems, and prevents the varnish from adhering to a portion of the stator core where varnish impregnation is not necessary, thereby shortening the varnish impregnation time and improving the varnish impregnation rate. An object of the present invention is to provide a varnish impregnation apparatus and a varnish impregnation method.

The first invention comprises a rotating means capable of holding and rotating a stator core having a winding coil inserted therein,
Varnish dripping means for dripping varnish on the winding coil;
A vacuum tank in which the rotating means and the varnish dropping means are disposed;
A vacuum pump for evacuating the vacuum tank;
In positive pressure, while rotating the stator core by said rotation means, have rows dropping of the varnish by the varnish dropping means to the winding coil in said stator core, then evacuated in the vacuum tank by the vacuum pump A varnish impregnation apparatus characterized in that the inside of the vacuum tank is brought into a negative pressure state and then air is supplied into the vacuum tank so that the inside of the vacuum tank is brought into a positive pressure state again. (Claim 1).

The varnish impregnation apparatus of the present invention improves the impregnation of the varnish into the winding coil inserted and disposed in the stator core by alternately forming a negative pressure state and a positive pressure state.
That is, the varnish impregnation apparatus of the present invention includes the rotating means, the varnish dropping means, a vacuum tank, and a vacuum pump, and evacuating the vacuum tank by the vacuum pump and supplying air to the vacuum tank. It is configured to perform alternately.

When performing the dropping impregnation of varnish to insert disposed windings coils on the stator core with the varnish impregnation apparatus can adopt the following method.
That is, as the dropping impregnation method, firstly, to hold the stator core by the rotation means which is arranged in a vacuum tank, the vacuum tank in a positive pressure state, while rotating the stator core by the rotation means, the winding in the stator core The varnish is dropped onto the wire coil by the varnish dropping means. At this time, the dropped varnish is inserted from the coil end portion where a part of the winding coil protrudes from the axial end of the stator core, and the remaining portion of the winding coil is inserted into the slot of the stator core. Penetrate toward the installation.

Next, the vacuum tank is evacuated by a vacuum pump to bring the vacuum tank into a negative pressure state. At this time, evacuation is also performed in the slots of the stator core formed by inserting the winding coils. Therefore, the varnish that has penetrated into the insertion arrangement portion in the slot can more easily penetrate into the axial center portion of the slot.
Thereafter, air is supplied into the vacuum tank, and the inside of the vacuum tank is again brought into a positive pressure state. At this time, the varnish that has penetrated into the insertion portion in the slot is pressurized by the air supplied into the vacuum tank and can further penetrate into the axial center of the slot.

  Further, after the inside of the vacuum tank is brought into a positive pressure state, the varnish is dropped again on the winding coil, the inside of the vacuum tank is brought into a negative pressure state by the vacuum pump, and then brought to the positive pressure state again. Thereafter, the negative pressure state and the positive pressure state can be repeatedly formed in the same manner as described above, and varnish dripping impregnation can be performed.

For reference, as another drip impregnation method, first, the stator core is held by a rotating means disposed in the vacuum tank, and the vacuum tank is evacuated by a vacuum pump. At this time, evacuation in the slot of the stator core formed by inserting the winding coil is also performed, and the air remaining in the slot is reduced.

In addition to performing this vacuuming, the varnish is dropped onto the winding coil in the stator core by the varnish dropping means while rotating the stator core by the rotating means. At this time, the dropped varnish is inserted from the coil end portion where a part of the winding coil protrudes from the axial end of the stator core, and the remaining portion of the winding coil is inserted into the slot of the stator core. Penetrate toward the installation. And since the air in the slot is reduced, the penetration of the varnish into the insertion arrangement portion is accelerated.
The rotation of the stator core and the dripping of the varnish can be performed after the vacuum tank is in a negative pressure state.

Next, air is supplied into the vacuum tank to bring the inside of the vacuum tank into a positive pressure state. At this time, the varnish that has penetrated into the insertion portion in the slot is pressurized by the air supplied into the vacuum tank, and can more easily penetrate into the axial center of the slot.
In addition, after the vacuum tank is brought into a positive pressure state, the vacuum tank is again evacuated by the vacuum pump, and varnish is dropped onto the winding coil, and then the positive pressure state is again reached. Thereafter, the negative pressure state and the positive pressure state can be repeatedly formed in the same manner as described above, and varnish dripping impregnation can be performed.

For reference, the remaining one of the dripping impregnation methods is that the stator core is held by rotating means disposed in the vacuum tank, and the stator core is rotated by the rotating means, while the stator core is rotated by the varnish dropping means to the winding coil in the stator core. Drip varnish.
Then, evacuation of the vacuum tank by the vacuum pump and supply of air to the vacuum tank are repeated, and dripping impregnation of the varnish is performed while appropriately changing the vacuum tank between a negative pressure state and a positive pressure state. Also by this, the varnish that has penetrated into the insertion portion in the slot can be easily penetrated into the central portion in the axial direction of the slot.

Thus, by dripping the varnish while rotating the stator core using the rotating means, it is possible to prevent the varnish from being locally biased and impregnated in the circumferential direction of the winding coil.
Moreover, since dripping of the varnish is directly performed on the winding coil, it is possible to prevent the varnish from adhering to the axial end portion, the outer peripheral portion, and the inner peripheral portion of the stator core.

  Therefore, according to the varnish impregnation apparatus of the present invention, the varnish impregnation in the stator core is performed by repeatedly forming the negative pressure state and the positive pressure state, and dropping the varnish while rotating the stator core in at least one of the states. It is possible to prevent the varnish from adhering to an unnecessary part, shorten the varnish impregnation time, and improve the varnish impregnation rate.

A second invention is a varnish impregnation method in which a winding coil inserted and disposed in a stator core is dripped and impregnated with a varnish.
In a positive pressure state, while rotating the stator core arranged in the vacuum tank, varnish is dropped onto the winding coil in the stator core, and then the vacuum tank is evacuated by a vacuum pump , In the varnish impregnation method, the inside of the tank is brought into a negative pressure state, then air is supplied into the vacuum tank, and the inside of the vacuum tank is brought into a positive pressure state again (Claim 4).

The varnish impregnation method of the present invention improves the impregnation of the varnish into the winding coil inserted and disposed in the stator by alternately forming a negative pressure state and a positive pressure state.
And also in this invention, the said dripping impregnation method is employable similarly to the invention of the said varnish impregnation apparatus.

  Therefore, according to the varnish impregnation method of the present invention, it is possible to prevent the varnish from adhering to a portion of the stator core that does not require varnish impregnation, shorten the varnish impregnation time, and improve the varnish impregnation rate.

A preferred embodiment in the first and second inventions described above will be described.
In the first and second inventions, the negative pressure state can be any vacuum pressure state lower than atmospheric pressure. For example, the negative pressure state can be set to -0.01 to -0.1 [MPa · G]. Further, the positive pressure state can be an atmospheric pressure state, or can be set to, for example, 0 to 0.1 [MPa · G].
In addition, the negative pressure state and the positive pressure state are repeated as many as two or more sets when the formation of the negative pressure state and the positive pressure state (formation of the positive pressure state and the negative pressure state) is one set. Can be formed. For example, the number of times of repeatedly forming the negative pressure state and the positive pressure state can be 2 to 10 sets.

  In the first aspect of the invention, the varnish impregnating apparatus has energizing means for energizing the winding coil, and the dropping of the varnish from the varnish dropping means to the winding coil is performed by the energizing means. It is preferable to carry out while energizing the winding coil. In the second aspect of the invention, it is preferable that the varnish is dropped while energizing the winding coil.

  In these cases, by energizing the winding coil, the winding coil self-heats due to its electric resistance, and by generating a magnetic field by energization, an eddy current is generated in the stator core, and the stator core is inductively heated. The winding coil can be heated. Therefore, the winding coil can be heated from the inside, and the varnish can be more rapidly permeated into the insertion portion of the winding coil inserted and disposed in the slot of the stator core. Therefore, the impregnation time of the varnish can be further shortened, and the impregnation rate of the varnish can be further improved.

In the first aspect of the invention, it is preferable that an air blower for supplying air into the vacuum tank is connected to the vacuum tank.
In this case, air can be rapidly supplied into the vacuum tank by the air blower, and the time for performing the drop impregnation of the varnish can be further shortened.

Below, the varnish impregnation apparatus and the varnish impregnation method concerning the Example of this invention are demonstrated with drawing.
Example 1
As shown in FIGS. 1 to 3, the varnish impregnation apparatus 1 of this example holds the stator core 91 in which the winding coil 92 is inserted and is rotatable, and the energization that energizes the winding coil 92. Means 4, varnish dropping means 5 for dropping varnish on winding coil 92, vacuum tank 6 having rotating means 2 and varnish dropping means 5 disposed therein, and evacuation in vacuum tank 6 And a vacuum pump 71 to perform.

The vacuum tank 6 is formed with an air supply port 62 for supplying air into the vacuum tank 6 and an air exhaust port 61 to which a vacuum pump 71 is connected. An air blower 72 that supplies air into the vacuum tank 6 is connected to the air supply port 62.
The varnish impregnation apparatus 1 is configured to alternately perform evacuation of the vacuum tank 6 by the vacuum pump 71 and supply of air to the vacuum tank 6 by the air blower 72.

Further, the varnish impregnation apparatus 1 rotates the stator core 91 by the rotating means 2 and supplies the winding coil 92 to the winding coil 92 in the stator core 91 while energizing the winding coil 92 by the energizing means 4 in the atmospheric pressure state as a positive pressure state. The varnish dropping means 5 is configured to drop the varnish.
This will be described in detail below.

As shown in FIGS. 1 and 2, the varnish impregnation apparatus 1 includes an energizing cable terminal 411 formed at the end of the energizing cable 41 in the energizing means 4 and a lead formed at the end of the lead wire 93 in the winding coil 92. A connection jig 8 for electrical connection with the line terminal 931 is provided. The connection jig 8 includes a cable side jig portion 81 to which the energizing cable terminal 411 is attached and a lead wire side jig portion 82 to which the lead wire terminal 931 is attached. The cable side jig portion 81 and the lead wire side. The jig part 82 is configured to be detachable from each other.
When the varnish is dropped and impregnated, the connection jig 8 electrically connects the terminal of the energizing cable 41 and the lead wire 93 terminal, and the energizing means 4 energizes the winding coil 92 in the stator 9. Possible states can be formed.

As shown in FIGS. 4 and 5, the object to be impregnated with the varnish by the varnish impregnation apparatus 1 of this example is a stator 9 used in a three-phase motor. The stator 9 is formed by inserting and arranging three-phase winding coils 92U, V, and W of a U-phase, a V-phase, and a W-phase in a stator core 91.
The winding coil 92 of each phase is formed by winding an electric wire a plurality of times, and is inserted into a slot 911 of the stator core 91, and a pair of insertion arrangement portions 921 and an axial end portion 913 of the stator core 91. And a pair of coil end portions 922 that protrude from the front end. In addition, the winding coil 92 of this example forms a continuous coil in which a plurality are connected. Further, the electric wire is formed by bundling a plurality of wires formed by insulating coating.

As shown in FIG. 4, the winding coil 92 is inserted and disposed in the stator core 91 in the order of the U phase, the V phase, and the W phase, and the coil end portion 922 of the U phase winding coil 92 </ b> U includes the stator core 91. The coil end portion 922 of the W-phase winding coil 92W is on the innermost side in the radial direction of the stator core 91, and the coil end portion 922 of the V-phase winding coil 92V is in the middle of both. It is arranged.
In addition, the lead wire terminal 931 of this example includes a U-phase, V-phase, and W-phase lead wire terminal 931 corresponding to the three-phase winding coil 92. The cable side jig portion 81 and the lead wire side jig portion 82 are configured to electrically connect the three energizing cable terminals 411 and the three-phase (three) lead wire terminals 931, respectively. Yes.

As shown in FIG. 1, the varnish impregnation apparatus 1 of this example can be controlled by the control means 10, and the rotating means 2, energizing means 4, varnish dropping means 5, vacuum pump 71 and air blower 72 are controlled by the control means 10. Is electrically connected.
That is, the control means 10 includes a timing at which the rotating means 2 rotates the stator core 91, a timing at which the winding coil 92 is energized by the energizing means 4, and a timing at which the varnish is dropped onto the winding coil 92 by the varnish dropping means 5. The timing of evacuating the vacuum tank 6 by the vacuum pump 71, the timing of supplying air into the vacuum tank 6 by the air blower 72, and the like can be controlled.
Further, the control means 10 of this example is configured to alternately repeat evacuation of the vacuum tank 6 by the vacuum pump 71 and supply of air to the vacuum tank 6 by the air blower 72 for a predetermined time. Yes.

The stator core 91 is embedded with a temperature detector (not shown) such as a thermistor. By detecting the temperature of the stator core 91 using this temperature detector, it is possible to monitor the temperature of the three-phase motor configured using the stator 9.
The connection jig 8 is connected only to the energizing cable terminal 411 and the lead wire terminal 931. However, in order to detect the temperature of the stator 9 when the varnish is impregnated, the temperature detector in the temperature detector is used. A wire terminal (not shown) can be connected to an input wire terminal (not shown) in the control means 10.
In this case, the control means 10 monitors the temperature of the stator core 91 detected by the temperature detector, and controls the energization means 4 so that the temperature of the stator core 91 becomes a temperature suitable for varnish impregnation. can do.

  As shown in FIG. 1 and FIG. 2, the rotating means 2 of this example is provided with a rotating motor 21, a rotating main shaft 22 connected to the output shaft of the rotating motor 21, and a movable main shaft 22. A chuck portion 23 capable of gripping the inner peripheral side of the stator core 91 and a torsion preventing mechanism 24 for preventing the energizing cable 41 in the energizing means 4 from being twisted when the stator core 91 is rotated by the rotating means 2. .

  The rotation main shaft 22 is disposed in the horizontal direction, and the chuck portion 23 is constituted by a plurality of movable chucks 231 that can protrude outward in the radial direction with respect to the rotation main shaft 22. Further, the chuck portion 23 presses a plurality of (for example, three or four) circumferential positions on the inner circumferential side of the stator core 91 by the movable chuck 231 with the axial direction of the stator core 91 oriented in the horizontal direction. The stator core 91 can be held. When the varnish is dropped and impregnated, the stator core 91 can be rotated with its axial direction set in the horizontal direction.

As shown in FIGS. 1 and 2, the rotary motor 21 of this example is configured to reciprocately rotate the rotary main shaft 22 at a predetermined rotation angle. The torsion prevention mechanism 24 is configured using a cable bearer 24 that holds the energization cable 41 and can be rotated by the rotation of the rotary main shaft 22.
When the rotary motor 21 is configured to continuously rotate the rotary main shaft 22 in one direction, the twist preventing mechanism 24 can be configured using a slip ring instead of using the cable bear 24. The slip ring is disposed in the middle of the energization cable 41, electrically connects one side and the other side of the energization cable 41, and by a plurality of connection ring portions formed around the central axis of the rotation main shaft 22. It can be rotated with electrical connection.

  As shown in FIG. 2, the rotating means 2 has a bracket 25 for fixing the cable side jig portion 81, and the energizing cable terminal 411 in the energizing means 4 is connected to the cable side jig portion fixed to the bracket 25. 81. Further, the cable side jig portion 81 is fixed to the bracket 25 so as to be able to face the cable side jig portion 81.

As shown in FIGS. 1 and 2, the transport means 3 of this example advances and retreats between the placement portion 31 on which the stator core 91 is placed and the outer circumference side of the rotation main shaft 22 in the rotation means 2. And a slide mechanism 32. The slide mechanism 32 is configured to move the mounting portion 31 forward and backward in the same direction as the axial direction of the rotary main shaft 22 in the rotating means 2, and rotates the stator 9 before impregnating the varnish mounted on the mounting portion 31. The main shaft 22 is carried in and the varnish-impregnated stator 9 is carried out from the rotary main shaft 22.
In addition, the slide mechanism 32 is comprised by the conveyance conveyor etc., and can be made to advance / retreat using a conveyance motor.

  As shown in FIG. 1, the energizing means 4 of this example is constituted by a high-frequency power supply device 40 that generates a three-phase high-frequency current. The high-frequency power supply device 40 outputs a three-phase high-frequency current that is out of phase to the stator core. The three-phase winding coil 92 inserted and disposed in 91 is energized. In addition, the energization cable terminal 411 is crimped to the distal end portion of the energization cable 41 through which a current for energization from the high frequency power supply device 40 flows.

Moreover, the high frequency power supply device 40 can form a high frequency current by increasing the frequency of a commercial three-phase AC power supply using an inverter or the like.
The energization means 4 energizes the winding coil 92 in the stator 9 to cause the winding coil 92 to self-heat due to its electric resistance, and to generate an eddy current in the stator core 91 due to the generation of a magnetic field by energization. By induction heating 91, the stator 9 can be heated to a temperature suitable for varnish dripping impregnation.

  As shown in FIGS. 1 and 2, the varnish dropping means 5 of this example includes a storage tank (not shown) for storing the varnish, a pump (not shown) for feeding the varnish from the storage tank, and this pump. A liquid feed pipe connected to the discharge port, a varnish dropping nozzle 51 connected to the tip of the liquid feed pipe, and a valve (not shown) disposed in the liquid feed pipe.

The varnish dropping nozzle 51 includes a U-phase nozzle 51U that drops varnish on the U-phase winding coil 92, a V-phase nozzle 51V that drops varnish on the V-phase winding coil 92, and a W-phase winding coil. 92 has a W-phase nozzle 51W for dropping varnish. The U-phase nozzle 51U and the V-phase nozzle 51V are disposed at positions where varnish is dropped from the outer peripheral side of the stator core 91 with respect to the U-phase winding coil 92 and the V-phase winding coil 92, respectively. . The W-phase nozzle 51 </ b> W is disposed at a position where varnish is dropped from the inner peripheral side of the stator core 91 with respect to the W-phase winding coil 92.
Further, the varnish is dropped by the nozzles 21U, V, and W with respect to the coil end portion 922 formed by protruding a part of the winding coil 92 from the axial end portion 913 of the stator core 91.

As shown in FIGS. 1 and 2, the vacuum tank 6 of this example includes a container body 65 and an opening / closing door 66 that can be opened and closed with respect to the container body 65. Further, the slide mechanism 32 of the transport means 3 of this example advances the placement portion 31 into the container main body 65 with the open / close door 66 of the vacuum tank 6 opened, and carries the stator core 91 to the rotation means 2. It is configured as follows.
Further, as shown in FIG. 3, the vacuum tank 6 of this example detects an exhaust deodorizing device 73 that exhausts the solvent in the varnish that evaporates when the varnish is heated, and the concentration of the evaporated solvent and the like. A gas concentration detector 731 is provided. The control means 10 is configured to monitor the concentration of the solvent or the like detected by the gas concentration detector 731 and control the heating amount by the energization means 4.

Next, a method for impregnating the varnish into the winding coil 92 inserted and disposed in the stator core 91 using the varnish impregnation apparatus 1 will be described, and the effects thereof will be described.
In this example, the cycle of varnish dripping → evacuation → positive pressure is repeated.
As shown in FIG. 2, in performing the varnish impregnation, first, a stator core 91 into which the winding coil 92 is inserted and placed is placed on the placing portion 31 in the conveying means 3, and the end of the winding coil 92 is placed. The lead wire side jig portion 8 is attached to the lead wire terminal 931 formed in the portion.

Next, the stator core 91 placed on the placement portion 31 is carried by the slide mechanism 32 in the transport means 3 to the outer peripheral side of the rotation main shaft 22 in the rotation means 2 disposed in the vacuum tank 6. At this time, the cable side jig part 81 and the lead wire side jig part 82 are connected to each other, and a state in which the electricity supply means 4 can energize the three-phase winding coil 92 in the stator core 91 is formed.
As shown in FIG. 1, when the stator core 91 is carried to the outer peripheral side of the rotation main shaft 22, the chuck portion 23 in the rotating means 2 is operated, and the stator core 91 is held by the plurality of movable chucks 231 in the chuck portion 23.

  Next, as shown in FIG. 1, the varnish dropping means 5 applies the varnish dropping means 5 to the coil end portion 922 of the winding coil 92 in the stator core 91 while rotating the stator core 91 by the rotating means 2 in the vacuum tank 6 in the atmospheric pressure state. Is dropped. At this time, the dropped varnish penetrates from the coil end portion 922 toward the insertion arrangement portion 921.

Next, the vacuum tank 71 is evacuated to bring the vacuum tank 6 into a negative pressure state (vacuum pressure state). At this time, evacuation is also performed in the slot 911 of the stator core 91 into which the winding coil 92 is inserted (see FIG. 4). Therefore, the varnish that has penetrated into the insertion arrangement portion 921 in the slot 911 can more easily penetrate into the axial center of the slot 911.
The negative pressure state can be set to -0.05 to -0.1 [MPa · G].

  Then, air is supplied into the vacuum tank 6 by the air blower 72, and the inside of the vacuum tank 6 is again brought into the atmospheric pressure state. At this time, the varnish that has penetrated into the insertion arrangement portion 921 in the slot 911 is pressurized by the air supplied into the vacuum tank 6 and can further penetrate into the axial center portion of the slot 911.

  Further, after the inside of the vacuum tank 6 is brought into the atmospheric pressure state, the varnish is dropped again on the winding coil 92, the inside of the vacuum tank 6 is brought into the negative pressure state by the vacuum pump 71, and thereafter, the atmospheric pressure state is brought back again. . Thereafter, the negative pressure state and the atmospheric pressure state are repeatedly formed as appropriate, and the varnish can be dropped and impregnated.

In this manner, by dropping the varnish while rotating the stator core 91 using the rotating means 2, it is possible to prevent the varnish from being locally biased and impregnated in the circumferential direction of the winding coil 92. it can.
Further, since the varnish is dropped directly on the winding coil 92, the axial end 913, the outer peripheral portion, and the inner peripheral portion of the stator core 91 (the inner peripheral surface of the teeth 912 formed between the slots 911). It is possible to prevent the varnish from adhering to (see FIG. 4).

  Therefore, according to the varnish impregnation apparatus 1 and the varnish impregnation method of the present example, adhesion of the varnish to the portion of the stator core 91 where varnish impregnation is not necessary is prevented, the varnish impregnation time is shortened and the varnish impregnation rate is reduced. Can be improved.

( Reference Example 1 )
This example is an example showing a method of rotating the stator core 91 and dropping varnish in a negative pressure state. In this example, the cycle of evacuation / varnish dropping → positive pressure is repeated.
That is, in this example, first, the stator core 91 is held by the rotating means 2 arranged in the vacuum tank 6, and the vacuum tank 71 is evacuated by the vacuum pump 71. At this time, evacuation in the slot 911 of the stator core 91 formed by inserting the winding coil 92 is also performed, and the air remaining in the slot 911 is reduced.

  Further, while vacuuming is performed by the vacuum pump 71 and the stator core 91 is rotated by the rotating means 2, the varnish is dropped onto the coil end portion 922 of the winding coil 92 in the stator core 91 by the varnish dropping means 5. At this time, the dropped varnish penetrates from the coil end portion 922 toward the insertion arrangement portion 921. Further, since the air in the slot 911 is reduced, the penetration of the varnish into the insertion arrangement portion 921 is accelerated.

The rotation of the stator core 91 and the dripping of the varnish can be performed after the vacuum tank 6 is in a negative pressure state.
Further, when the varnish is dropped in the negative pressure state, if the degree of the negative pressure is too large, the varnish may be defoamed. Therefore, when the vacuum pump 71 is evacuated, the pressure in the vacuum tank 6 is −0. It is preferable to carry out so that it may become 0.01--0.07 [MPa * G].

Next, air is supplied into the vacuum tank 6 by the air blower 72 to bring the inside of the vacuum tank 6 into an atmospheric pressure state. At this time, the varnish that has penetrated into the insertion portion 921 in the slot 911 is pressurized by the air supplied into the vacuum tank 6, and can more easily penetrate into the axial center of the slot 911. . Further, after the inside of the vacuum tank 6 is brought into the atmospheric pressure state, the inside of the vacuum tank 6 is again brought into the negative pressure state by the vacuum pump 71 and the varnish is dropped onto the winding coil 92, and then the atmospheric pressure state again. To. Thereafter, the negative pressure state and the atmospheric pressure state are repeatedly formed as appropriate, and the varnish can be dropped and impregnated.
Also in this example, other configurations and operations are the same as those in the first embodiment, and the same effects as those in the first embodiment can be obtained.

( Reference Example 2 )
In this example, the stator core 91 is rotated and the varnish is dropped in both the atmospheric pressure state and the negative pressure state. In this example, the evacuation → positive pressure cycle is repeated while the varnish is dropped.
In other words, in this example, the stator core 91 is held by the rotating means 2 disposed in the vacuum tank 6, and the stator core 91 is rotated by the rotating means 2 while the varnish dropping means 5 rotates the coil of the winding coil 92 in the stator core 91. The varnish is dropped onto the end portion 922.

Then, evacuation in the vacuum tank 6 by the vacuum pump 71 and supply of air to the vacuum tank 6 are repeated, and dripping of the varnish while appropriately changing the vacuum tank 6 between a negative pressure state and an atmospheric pressure state. Impregnation is performed. Also by this, the varnish that has permeated the insertion arrangement portion 921 in the slot 911 can be easily permeated into the central portion of the slot 911 in the axial direction.
Also in this example, when the varnish is dropped in the negative pressure state, the negative pressure state in the vacuum tank 6 is preferably -0.01 to -0.07 [MPa · G].
Also in this example, other configurations and operations are the same as those in the first embodiment, and the same effects as those in the first embodiment can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the varnish impregnation apparatus of Example 1 and the reference examples 1 and 2 in the state which performs the dripping impregnation of a varnish. Explanatory drawing which shows the varnish impregnation apparatus of the state before Example 1 and the reference examples 1 and 2 before conveying a stator core to a rotation means. BRIEF DESCRIPTION OF THE DRAWINGS Overall explanatory drawing which shows the varnish impregnation apparatus in Example 1 and Reference Examples 1 and 2. FIG. FIG. 3 is an explanatory diagram showing the stator in the first embodiment and the first and second reference examples as viewed from the axial direction of the stator core. Explanatory drawing which shows the stator in Example 1 and the reference examples 1 and 2 typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Varnish impregnation apparatus 2 Rotating means 3 Conveying means 4 Current supply means 5 Varnish dripping means 6 Vacuum tank 71 Vacuum pump 72 Air blower 9 Stator 91 Stator core 911 Slot 92 Winding coil 921 Insertion arrangement part 922 Coil end part

Claims (5)

Rotating means capable of holding and rotating the stator core with the winding coil inserted therein,
Varnish dripping means for dripping varnish on the winding coil;
A vacuum tank in which the rotating means and the varnish dropping means are disposed;
A vacuum pump for evacuating the vacuum tank;
In a positive pressure state, while rotating the stator core by the rotating means, the varnish is dropped by the varnish dropping means to the winding coil in the stator core, and then the vacuum tank is evacuated by the vacuum pump. A varnish impregnation apparatus characterized in that the vacuum tank is made to be in a negative pressure state, then air is supplied into the vacuum tank, and the vacuum tank is again brought into a positive pressure state.   2. The varnish impregnation apparatus according to claim 1, further comprising energizing means for energizing the winding coil, and dropping of the varnish from the varnish dropping means to the winding coil is performed by the energizing means. A varnish impregnation apparatus characterized in that the varnish impregnation is performed while energizing a wire coil.   3. The varnish impregnation apparatus according to claim 1, wherein an air blower for supplying air into the vacuum tank is connected to the vacuum tank. In the varnish impregnation method of dripping and impregnating the varnish into the winding coil inserted and arranged in the stator core,
In a positive pressure state, while rotating the stator core arranged in the vacuum tank, varnish is dropped onto the winding coil in the stator core, and then the vacuum tank is evacuated by a vacuum pump , A varnish impregnation method, wherein the inside of a tank is brought into a negative pressure state, then air is supplied into the vacuum tank, and the inside of the vacuum tank is brought into a positive pressure state again.   5. The varnish impregnation method according to claim 4, wherein the varnish is dropped while energizing the winding coil.

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