JPWO2019026340A1 - Vacuum pump - Google Patents

Abstract

A vacuum pump according to one embodiment of the present invention includes a first unit and a second unit. The first unit includes a rotor core, a first rotating shaft that supports the rotor core and extends in a uniaxial direction, and a pump housing that houses the first rotating shaft. The second unit includes a cylindrical member, a stator core, a motor housing, a seal ring, and a regulating member. The cylindrical member has an open end and a closed end, and accommodates the rotor core. The stator core is disposed around the cylindrical member. The motor housing contains a cylindrical member and a stator core and is coupled to the pump housing. The seal ring is disposed between the cylindrical member and the motor housing. The restricting member is attached to the motor housing and faces the opening end of the cylindrical member in the uniaxial direction.

Description

  The present invention relates to a vacuum pump having a canned motor.

  As a volumetric transfer type dry vacuum pump, for example, a biaxial screw pump is known. This type of screw pump includes a housing having a suction port and a discharge port, and a pair of screw shafts housed in the housing, and transfers gas from the suction port to the discharge port by rotating the pair of screw shafts. Configured to do.

  On the other hand, in this type of vacuum pump, a canned motor is widely used as a drive source for rotating each screw shaft. The canned motor has a cylindrical can inserted into a gap between the rotor core and the stator core. Since the rotor core is sealed by the can, leakage of gas that has entered the rotor core through the bearing portion to the atmosphere (outside air) side is prevented.

  For example, in Patent Document 1, a can opening is formed in a flange shape, and the rotor and the stator core are hermetically isolated by a seal ring disposed along the periphery of the flange-shaped opening. A motor is disclosed.

JP 2014-39366 A

  In a vacuum pump provided with a canned motor, typically, after the can is mounted on the stator core side via a seal ring, the rotor core is incorporated into the can. At this time, due to the magnetic interaction between the rotor core and the stator core, the rotor core comes into contact with the inner peripheral surface of the can, and the relative position between the stator core and the can changes. The seal ring may fall off.

  In view of the circumstances as described above, an object of the present invention is to provide a vacuum pump capable of preventing the positional deviation of the seal ring and improving the assembly workability.

In order to achieve the above object, a vacuum pump according to an embodiment of the present invention includes a first unit and a second unit.
The first unit includes a rotor core, a first rotating shaft that supports the rotor core and extends in a uniaxial direction, and a pump housing that houses the first rotating shaft.
The second unit includes a cylindrical member, a stator core, a motor housing, a seal ring, and a regulating member. The cylindrical member has an open end and a closed end, and accommodates the rotor core. The stator core is disposed around the cylindrical member. The motor housing accommodates the cylindrical member and the stator core and is coupled to the pump housing. The seal ring is disposed between the cylindrical member and the motor housing. The restriction member is attached to the motor housing and faces the opening end of the cylindrical member in the uniaxial direction.

  According to the vacuum pump, the displacement of the cylindrical member in the second unit is suppressed by the regulating member. Accordingly, when the first and second units are assembled, the seal ring in the second unit can be prevented from being displaced or dropped, and the assembly workability can be improved.

The motor housing may include a mounting portion that supports the seal ring, and the cylindrical member may further include a first cylindrical portion, a second cylindrical portion, and a stepped portion.
The first cylindrical portion includes the open end portion and contacts the seal ring. The second cylindrical portion includes the closed end portion and has an outer diameter smaller than that of the first cylindrical portion. The step portion is provided between the first cylindrical portion and the second cylindrical portion, and has an outer diameter continuously or stepwise from the first cylindrical portion toward the second cylindrical portion. to shrink.
Thereby, the position shift of the seal ring supported by the mounting portion can be prevented when the cylindrical member is assembled to the stator core.

The first unit further includes a second rotating shaft and a timing gear attached to the first rotating shaft and rotating the second rotating shaft, and the motor housing houses the stator core. You may have a motor chamber and the gear chamber which accommodates the said timing gear.
This eliminates the need for a separate casing for forming the gear chamber, and can further improve the assembly workability.

  The closed end of the cylindrical member may have a dome shape. Thereby, the intensity | strength improvement of a cylindrical member can be aimed at.

A method for assembling a vacuum pump according to an aspect of the present invention includes preparing a first unit in which a first rotating shaft that supports a rotor core is incorporated in a pump housing.
The motor housing includes a cylindrical member, a stator core disposed around the cylindrical member, a seal ring disposed between the outer peripheral surface of the cylindrical member and the inner peripheral portion of the motor housing, and an open end of the cylindrical member A second unit incorporating a restricting member facing the part is prepared.
The rotor core is accommodated in the cylindrical member, and the pump housing and the motor housing are coupled to each other.

  As described above, according to the present invention, it is possible to improve the assembly workability by preventing the positional deviation of the seal ring.

It is a cross-sectional view of a vacuum pump according to an embodiment of the present invention. It is a transverse cross section of a vacuum pump which shows the 1st and 2nd unit in the above-mentioned vacuum pump separately. It is an expanded sectional view of the cylindrical member which comprises the said 2nd unit. It is a schematic sectional drawing of the principal part of the said 2nd unit explaining the effect | action of the said cylindrical member. It is a schematic sectional drawing which shows one structural example of the canned motor which concerns on a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Configuration of vacuum pump]
FIG. 1 is a cross-sectional view of a vacuum pump according to an embodiment of the present invention.
In the figure, the X axis, the Y axis, and the Z axis indicate three axial directions orthogonal to each other, and the Z axis corresponds to the height direction.

  The vacuum pump 100 of the present embodiment is configured with a screw pump. The vacuum pump 100 includes a first unit U1 and a second unit U2. FIG. 2 is a cross-sectional view of the vacuum pump 100 showing the first unit U1 and the second unit U2 separately.

(First unit)
The first unit U1 constitutes a pump body of the vacuum pump 100. The first unit U1 includes a pump housing 11 and first and second screw shafts 21 and 22 (first and second rotating shafts).

  The pump housing 11 has a first housing part 111 and a second housing part 112. The first and second housing portions 111 and 112 are made of a metal material such as an aluminum alloy or stainless steel, and are connected to each other via a positioning pin P1 and an annular seal member S1. The positioning pins P1 are provided at a plurality of positions on the outer peripheral side of the seal member S1.

  The first housing portion 111 includes a pump chamber 13 that rotatably accommodates the first and second screw shafts 21 and 22, and an intake port 14 that is connected to an exhaust pipe of a vacuum chamber (not shown). The second housing portion 112 has a pair of through holes H through which the first and second screw shafts 21 and 22 pass, and an exhaust port 15 communicating with the pump chamber 13. For example, a silencer or an exhaust gas detoxifying device may be connected to the exhaust port 15.

  The first and second screw shafts 21 and 22 each have an axis parallel to the Y-axis direction, and are disposed in the pump chamber 13 adjacent to each other in the X-axis direction. The first screw shaft 21 has spiral teeth 21s, and the second screw shaft 22 has spiral teeth 22s that mesh with the teeth 21s. Each of the first and second screw shafts 21 and 22 is constituted by a single screw.

  The teeth 21s and 22s have substantially the same shape except that the twisting directions are opposite to each other. The teeth 21 s and 22 s mesh with each other with a slight gap so that one tooth is located between the other teeth (grooves). The outer peripheral surface of the tooth 21s is opposed to the inner wall surface of the pump chamber 13 and the outer peripheral surface of the shaft portion of the second screw shaft 22 (the bottom portion of the groove between the teeth 22s) with a slight gap. On the other hand, the outer peripheral surface of the teeth 22s is opposed to the inner wall surface of the pump chamber 13 and the outer peripheral surface of the shaft portion of the first screw shaft 21 (the bottom of the groove between the teeth 21s) with a slight gap.

  The intake port 14 and the exhaust port 15 communicate with each other via the pump chamber 13. The intake port 14 is provided on the suction end side of the first and second screw shafts 21, 22, and the exhaust port 15 is provided on the discharge end side thereof. The first and second screw shafts 21 and 22 are rotatably disposed in the pump chamber 13 via bearings B1 and B2 installed on the suction end side and the discharge end side thereof.

  The positions of the intake port 14 and the exhaust port 15 are not limited to the above example, and can be changed as appropriate. For example, the exhaust port 15 may be provided in the first housing part 111. The pump housing 11 is not limited to the case where the first and second housing portions 111 and 112 are combined. The pump housing 11 may be formed of a single housing part or a combination of three or more housing parts. May be. In the case where the pump housing 11 is configured by combining three or more housing parts, the intake port 14 is provided, for example, in a housing portion located on the most intake side.

  The first screw shaft 21 is connected to a motor 40 that is a drive source of the vacuum pump 100. The first screw shaft 21 is provided with a synchronous gear 23 that meshes with a synchronous gear 24 attached to the discharge end side shaft portion of the second screw shaft 22, and is attached to the first screw shaft 21 by the motor 40. The rotational driving force is transmitted to the second screw shaft 22 via the synchronous gears 23 and 24. The motor 40 rotates the first and second screw shafts 21 and 22 so as to transfer the gas in the vacuum chamber sucked from the intake port 14 toward the exhaust port 15.

  The first unit U <b> 1 further includes a rotor core 41 that is one component of the motor 40. The rotor core 41 is supported (press-fitted) on the distal end portion (the distal end portion of the discharge end side shaft portion) 21a of the first screw shaft 21. The motor 40 may be a DC motor or an AC motor. In the present embodiment, the rotor core 41 is made of a cylindrical permanent magnet material in which N poles and S poles are alternately arranged in the circumferential direction, but may be made of an electromagnet.

(Second unit)
Next, the second unit U2 will be described.

  The second unit U2 is configured as a motor unit that drives the pump body. The second unit U2 includes a motor housing 31, a cylindrical member 32, a stator core 42, which is one component of the motor 40, a seal ring S3 disposed between the motor housing 31 and the cylindrical member 32, and a regulating member. 34.

  The motor housing 31 is made of a metal material such as aluminum alloy or stainless steel, and is connected to the pump housing 11 (second housing portion 112) via a positioning pin P2 and an annular seal member S2. The positioning pins P2 are provided at a plurality of positions on the outer peripheral side of the seal member S2. The motor housing 31 is provided with an internal passage 313 through which a cooling medium such as cooling water circulates.

  The motor housing 31 includes a motor chamber 311 that holds the stator core 42 and a gear chamber 312 that accommodates the synchronous gears 23 and 24.

  The motor chamber 311 is formed by a substantially cylindrical space. The opening end of the motor chamber 311 opposite to the gear chamber 312 is covered with a protection plate 33 attached to the tip of the motor housing 31 via a plurality of screws N1. The protection plate 33 is made of a plate material having an opening such as a lattice plate or punch metal, for example, and the motor chamber 311 communicates with the outside air (atmosphere) through the opening. Thereby, the heat dissipation effect of the motor chamber is enhanced.

  The gear chamber 312 is defined between the motor housing 31 and the pump housing 11 (second housing portion 112), and can store lubricating oil (not shown) that lubricates the synchronous gears 23 and 24 and the bearing B2. Configured. The gear chamber 312 is configured to be able to communicate with the pump chamber 13 through the bearing B <b> 2 and the through hole H of the pump housing 11. The through hole H may be provided with a contact type or non-contact type seal that partitions the pump chamber 13 and the gear chamber 312.

  The motor housing 31 further includes an annular support wall 314 (see FIG. 2) formed between the motor chamber 311 and the gear chamber 312. The support wall 314 protrudes radially inward from the motor chamber 311, and a mounting groove in which a seal ring S <b> 3 in contact with the outer peripheral surface of the cylindrical member 32 is mounted is formed at the inner peripheral end. The support wall portion 314 is configured as a mounting portion that supports the seal ring S3.

  The stator core 42 is accommodated in the motor chamber 311. The stator core 42 is composed of a laminated body of a plurality of magnetic steel plates formed in an annular shape, and is disposed around the cylindrical member 32. A plurality of coils 43 of U, V, and W phases connected to a power source (not shown) are wound around the stator core 42.

  The outer peripheral surface of the stator core 42 is fixed to the inner peripheral surface of the motor chamber 311. The fixing method is not particularly limited. In the present embodiment, the outer peripheral surface of the stator core 42 is fixed to the motor chamber 311 by shrink fitting. The inner peripheral surface of the stator core 42 is opposed to the outer peripheral surface of the rotor core 41 with the cylindrical member 32 interposed therebetween.

  The cylindrical member 32 is disposed between the rotor core 41 and the stator core 42 and accommodates the rotor core 41 therein. The cylindrical member 32 has an axial center that is concentric with the first screw shaft 21, and the axial length (the height of the cylindrical member 32) is the thickness of the support wall 314 and the axial direction of the motor chamber 311. It almost matches the total length.

  FIG. 3 is an enlarged cross-sectional view of the cylindrical member 32.

  The cylindrical member 32 is configured by an injection molded body of a synthetic resin material such as PPS (polyphenylene sulfide) having an open end 321 and a closed end 322. By forming the cylindrical member 32 from a nonmagnetic, nonconductive synthetic resin material, desired motor characteristics can be ensured without hindering electromagnetic interaction between the rotor core 41 and the stator core 42. it can.

  The cylindrical member 32 is formed of a stepped cylindrical body, and includes a first cylindrical portion 323, a second cylindrical portion 324, and a step portion 325.

  The first cylindrical portion 323 includes an open end 321 and has an outer peripheral surface that comes into contact with the seal ring S3. The second cylindrical portion 324 includes a closed end portion 322 and has an outer diameter smaller than that of the first cylindrical portion 323. For example, the second cylindrical portion 324 has an outer diameter equivalent to the inner diameter of the stator core 42. The outer diameter of the step portion 325 decreases continuously or stepwise from the first cylindrical portion 323 toward the second cylindrical portion 324. The step portion 325 typically includes a tapered surface. However, the step portion 325 may be configured so that the diameter is discretely reduced stepwise.

  Both the first and second cylindrical portions 323 and 324 have the same inner diameter. That is, the first cylindrical portion 323 is formed thicker than the second cylindrical portion 324, and the strength on the opening end 321 side is improved. The closed end 322 is also formed thicker than other regions of the second cylindrical portion 324, so that the strength of the closed end 322 can be improved. In addition, since the closed end 322 is formed in a dome shape, the stress associated with the fluctuation of the internal pressure of the cylindrical member 32 can be dispersed. A rib for improving the strength may be provided on the outer surface of the closed end 322.

  Further, since the cylindrical member 32 has the stepped portion 325, when the cylindrical member 32 is assembled to the motor chamber 311, it is possible to prevent the seal ring S3 from dropping from the support wall portion 314 (mounting portion). And the 2nd cylindrical part 324 is formed thinly, The magnetic gap between the rotor core 41 and the stator core 42 can be made small.

  For example, as shown in FIGS. 4A to 4C, the cylindrical member 32 is inserted into the motor chamber 311 from the gear chamber 312 side. At this time, the seal ring S <b> 3 attached to the support wall portion 314 is in sliding contact with the outer peripheral surface of the first cylindrical portion 323 via the step portion 325 of the cylindrical member 32. Since the step portion 325 is configured with the tapered surface as described above, the seal ring S3 can get over the step portion 325 without dropping from the mounting groove of the support wall portion 314 and reach the first cylindrical portion 323. Can do.

  The cylindrical member 32 is inserted into the motor chamber 311 until the step portion 325 is in contact with the inner peripheral end portion of the stator core 42. At this time, the opening end portion 321 of the cylindrical member 32 is positioned to align with the opening surface 314a (see FIG. 3) of the support wall portion 314 on the gear chamber 312 side, or positioned closer to the motor chamber 311 than the opening surface 314a. The closed end 322 of the cylindrical member 32 may be in contact with the protective plate 33 or may be opposed to the protective plate 33 with a predetermined gap.

  The regulating member 34 is for preventing the cylindrical member 32 from being detached from the motor chamber 311. The restriction member 34 is attached to the support wall portion 314 via a plurality of screw members N2, and faces the opening end portion 321 of the cylindrical member 32 in the Y-axis direction. The regulating member 34 is in contact with the opening end 321 of the cylindrical member 32 and regulates the movement of the cylindrical member 32 in the axial direction relative to the stator core 42.

  The regulating member 34 is configured by a plate-like component having an opening 341. The size of the opening 341 is larger than the outer diameter of the rotor core 41, and has an arbitrary size smaller than the outer diameter of the opening end 321 of the cylindrical member 32. In the present embodiment, the opening 341 has an opening diameter that is equal to the inner diameter of the opening end 321 of the cylindrical member 32.

  The regulating member 34 is typically made of a metal plate, but may be made of a synthetic resin material such as PPS. The thickness of the regulating member 34 is not particularly limited, and may be configured to be elastically deformable.

[Operation of vacuum pump]
Next, the operation of the vacuum pump 100 of the present embodiment configured as described above will be described.

  By driving the motor 40, the first screw shaft 21 and the second screw shaft 22 are relatively rotated. The gas in the vacuum chamber connected to the intake port 14 is transferred to the exhaust port 15 by the rotation of the first and second screw shafts 21 and 22. Thereby, the inside of the vacuum chamber is evacuated.

  The rotor core 41 is sealed by the cylindrical member 32. For this reason, the gas that has entered the gear chamber 312 and the rotor core 41 from the pump chamber 13 via the bearing B2 is prevented from leaking out of the pump (atmosphere). Furthermore, since the outside of the cylindrical member 32 is open to the atmosphere, the heat dissipation of the stator core 42 is enhanced, and in combination with the cooling effect by the cooling medium circulating in the internal passage 313 of the motor housing 31, it can be used at high loads. The deterioration of the characteristics of the motor 40 is suppressed.

  Further, since the closed end 322 of the cylindrical member 32 has a dome shape, the stress acting on the closed end 322 due to the pressure difference between the inside and outside of the cylindrical member 32 can be effectively dispersed. Thereby, the intensity | strength of the cylindrical member 32 can be improved.

  The cylindrical member 32 may be configured to be movable in the motor chamber 311 in the axial direction by a predetermined amount (for example, a displacement corresponding to the elastic deformation amount of the regulating member 34) due to the pressure difference. Even with such a structure, the pressure acting on the cylindrical member 32 can be reduced.

[Assembly method of vacuum pump]
Then, the assembly method of the vacuum pump 100 of this embodiment is demonstrated.

  In the method of assembling the vacuum pump 100 according to the present embodiment, the step of preparing the first unit U1, the step of preparing the second unit U2, and the first and second units U1 and U2 are coupled to each other. Process.

  As shown in FIG. 2, the first unit U <b> 1 is manufactured by incorporating a first screw shaft 21 that supports the rotor core 41 and a second screw shaft 22 into the pump housing 11.

  In the present embodiment, after the first and second screw shafts 21 and 22 are assembled in the first housing portion 111, the second housing portion 112 is moved to the first via the plurality of positioning pins P1 and the seal member S1. The housing part 111 is coupled. A plurality of bolts are used for coupling the first and second housing parts 111 and 112, not shown.

  The second unit U <b> 2 is disposed in the motor housing 31 between the cylindrical member 32, the stator core 42 disposed around the cylindrical member 32, and the outer peripheral surface of the cylindrical member 32 and the inner peripheral portion of the motor housing 31. The seal ring S3 and the regulating member 34 facing the opening end 321 of the cylindrical member 32 are assembled.

  In the present embodiment, the stator core 42 and the protection plate 33 are fixed to the motor chamber 311 of the motor housing 31, and the cylindrical member 32 is assembled in the motor chamber 311 after the seal ring S 3 is mounted in the mounting groove of the support wall 314. It is done. Since the cylindrical member 32 includes the step portion 325, the cylindrical member 32 can be stably assembled to the motor chamber 311 without dropping the seal ring S3 from the support wall portion 314 (FIGS. 4A to 4C).

  After the cylindrical member 32 is assembled, the regulating member 34 facing the open end 321 of the cylindrical member 32 is assembled to the motor housing 31 (support wall 314). The open end 321 may be in contact with the regulating member 34 or may face the regulating member 34 with a predetermined gap.

  In the coupling process of the first and second units U1 and U2, the pump housing 11 and the motor housing 31 have a plurality of positioning pins P2 in a state where the first and second units U1 and U2 are aligned in the Y-axis direction. And are coupled to each other via the seal member S2. A plurality of bolts are used for coupling the pump housing 11 and the motor housing 31 even if not shown.

  When the first and second units U1 and U2 are coupled, the rotor core 41 enters the cylindrical member 32 until the pump housing 11 and the motor housing 31 are in contact with each other. Since the cylindrical member 32 is fixed to the motor housing 31 via the seal ring S <b> 3, the rotor core 41 accommodated in the motor chamber 311 is sealed by the cylindrical member 32. Thereby, a canned motor is constituted.

  Here, when the rotor core 41 is incorporated toward the motor chamber 311, the inner surface of the cylindrical member 32 may come into contact with the stator core 42 due to magnetic interaction (magnetic force) with the stator core 42. In the present embodiment, the cylindrical member 32 is held inside the motor housing 31 while being sandwiched between the stator core 42 and the regulating member 34. For this reason, even if the cylindrical member 32 receives the contact pressure in the radial direction by the rotor core 41, the relative position in the motor chamber 311 is prevented from changing and the mounting position of the seal ring S3 is not changed. The rotor core 41 can be stably incorporated up to a position facing the stator core 42 in the circumferential direction.

  For example, FIG. 5 shows a configuration of a canned motor 500 according to a comparative example. In the figure, a cylindrical member 52 that accommodates the rotor core 61 has a flange-shaped opening end 521 and is attached to the motor housing 51 via a seal ring 80 disposed along the periphery of the opening end 521. . A rotating shaft 71 that supports the rotor core 61 is connected to the pump housing 54 via a bearing 72. The pump housing 54 is coupled to a motor housing 51 that houses the stator core 62 via an annular seal member 82.

  At this time, when the rotor core 61 is inclined with respect to the Y-axis direction and contacts the inner peripheral surface of the cylindrical member 52 due to the magnetic interaction between the rotor core 61 and the stator core 62, the attitude of the cylindrical member 52 changes or the cylindrical member 52 is changed. There is a possibility that the mounting position of the seal ring 80 is displaced due to the change in the posture or the seal ring 80 is dropped.

  Further, since the seal ring 80 is disposed around the flange-shaped opening end 521 of the cylindrical member 52, the seal ring 80 cannot get over the opening end 521 when the cylindrical member 52 is mounted on the motor housing 51. May be pushed away to the stator core 62 side, or the mounting position may be partially shifted. Since such a state of the seal ring 80 cannot be confirmed after the cylindrical member 52 is mounted, the canned motor 500 may be assembled without finding a sealing failure of the cylindrical member 52.

  On the other hand, according to the vacuum pump 100 of the present embodiment, as shown in FIG. 2, the cylindrical member 32 is held inside the motor housing 31 with being sandwiched between the stator core 42 and the regulating member 34. Therefore, the change in the relative position of the cylindrical member 32 in the motor chamber 311 is restricted. Thereby, even if the contact pressure in the radial direction is received by the rotor core 41, the mounting position of the cylindrical member 32 and the seal ring S3 is prevented from changing, and the assembling work is facilitated.

  In the canned motor 500 according to the comparative example, since the opening end 521 of the cylindrical member 52 has a flange shape, stress concentration is caused at the boundary between the flange portion and the cylindrical portion according to the pressure change inside the cylindrical member 52. There is a problem that the cylindrical member 52 is likely to be repeatedly damaged and easily damaged.

  On the other hand, in this embodiment, since the cylindrical member 32 is formed in a straight cylindrical shape having no flange portion at the opening end portion 321, the stress accompanying the pressure change inside the cylindrical member 32 is applied to the inside of the cylindrical member. Can be received on the entire wall. Thereby, even when the cylindrical member 32 is made of a relatively low-strength material such as a synthetic resin, the cylindrical member 32 is reliably prevented from being damaged by the pressure change, and the durability of the vacuum pump 100 is improved. Can be increased.

  Furthermore, according to the vacuum pump 100 of the present embodiment, since the regulating member 34 for positioning the cylindrical member 32 is provided in the motor chamber 311, a screw fastening portion is provided on the cylindrical member 32 and directly fixed to the motor chamber. As compared with the above, local deformation of the cylindrical member 32 due to the pressure change can be prevented. Moreover, since the open end 321 of the cylindrical member 32 attached to the support wall 314 via the seal ring S3 is formed in a cylindrical shape, the stress generated with the pressure change is applied to the circle of the open end 321. The desired pressure resistance characteristics of the cylindrical member 32 can be ensured by uniformly dispersing in the circumferential direction.

  On the other hand, according to the present embodiment, since the tapered step portion 325 is provided on the peripheral surface portion of the cylindrical member 32, when the cylindrical member 32 is assembled to the motor housing 31, the seal ring S <b> 3 varies in its mounting position. It is possible to stably ride up to the first cylindrical portion 323 side without causing the above. As a result, unintended displacement of the seal ring S3 due to the mounting of the cylindrical member 32 can be prevented, and the reliability of the seal ring S3 during pump assembly can be ensured, and the assembly workability can be improved. .

  Furthermore, according to this embodiment, since the motor housing 31 has not only the motor chamber 311 but also the gear chamber 312, a separate casing for forming the gear chamber 312 becomes unnecessary, and assembly workability is further improved. Improvements can be made.

  As mentioned above, although embodiment of this invention was described, this invention is not limited only to the above-mentioned embodiment, Of course, a various change can be added.

  For example, in the above embodiment, the screw pump has been described as an example of the vacuum pump 100. However, the present invention is not limited to this, and the present invention can also be applied to a roots pump or a mechanical booster pump.

  The present invention can also be applied to a rotary pump and a scroll pump having a single rotating shaft.

  Furthermore, the cylindrical member 32 does not have the step portion 325 and may be configured straight. In this case, for example, at the time of maintenance, the cylindrical member can be extracted from the front end side of the motor housing 31 to which the protection plate 33 is attached.

DESCRIPTION OF SYMBOLS 11 ... Pump housing 13 ... Pump chamber 14 ... Intake port 15 ... Exhaust port 21 ... 1st screw shaft 22 ... 2nd screw shaft 23, 24 ... Synchronous gear 31 ... Motor housing 311 ... Motor chamber 312 ... Gear chamber 314 ... Support wall portion 32 ... cylindrical member 321 ... open end portion 322 ... closed end portion 323 ... first cylindrical portion 324 ... second cylindrical portion 325 ... step portion 34 ... regulating member 40 ... motor 41 ... rotor core 42 ... stator core 100 ... Vacuum pump B1, B2 ... Bearing S3 ... Seal ring U1 ... First unit U2 ... Second unit

Claims (7)

A first unit comprising: a rotor core; a first rotating shaft that supports the rotor core and extends in a uniaxial direction; and a pump housing that houses the first rotating shaft;
A cylindrical member that has an open end and a closed end, and accommodates the rotor core; a stator core disposed around the cylindrical member; a motor that accommodates the cylindrical member and the stator core and is coupled to the pump housing A housing, a seal ring disposed between the cylindrical member and the motor housing, and a regulating member attached to the motor housing and opposed to the opening end of the cylindrical member in the uniaxial direction. A vacuum pump comprising: The vacuum pump according to claim 1,
The motor housing has a mounting portion that supports the seal ring,
The cylindrical member is
A first cylindrical portion including the open end and in contact with the seal ring;
A second cylindrical portion including the closed end and having an outer diameter smaller than the first cylindrical portion;
A step portion provided between the first cylindrical portion and the second cylindrical portion, the outer diameter of which decreases continuously or stepwise from the first cylindrical portion toward the second cylindrical portion; In addition, it has a vacuum pump. The vacuum pump according to claim 1 or 2,
The first unit further includes a second rotation shaft, and a synchronous gear attached to the first rotation shaft and rotating the second rotation shaft,
The motor housing includes a motor chamber that houses the stator core and a gear chamber that houses the synchronous gear. The vacuum pump according to claim 3,
The first and second rotating shafts are a pair of screw shafts. A vacuum pump according to any one of claims 1 to 4,
The said cylindrical member is a vacuum pump comprised with a synthetic resin material. A vacuum pump according to any one of claims 1 to 5,
The closed end has a dome shape. Preparing a first unit incorporating a first rotating shaft supporting a rotor core in a pump housing;
The motor housing includes a cylindrical member, a stator core disposed around the cylindrical member, a seal ring disposed between an outer peripheral surface of the cylindrical member and an inner peripheral portion of the motor housing, and an open end of the cylindrical member Preparing a second unit incorporating a regulating member facing the part,
A method for assembling a vacuum pump, wherein the rotor core is accommodated in the cylindrical member, and the pump housing and the motor housing are coupled to each other.

Images