JP2005240747A - Vane rotary type vacuum pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dissolve a problem that a shaft rattles in an axial direction, noise is increased due to rattling of a roll bearing, and the noise is increased due to rattling of a rotor around the shaft. <P>SOLUTION: A motor shaft 222 and a mechanical shaft 123 are supported by first and second rolling bearings 155 and 235. The first rolling bearing 155 is constituted that a motor shaft 222 is pressed in an inner ring 155a and fixed, a spring 241 is situated between a inner ring 235a of the second rolling bearing 235 and a fastener 223 situated on the motor shaft 222, and rattling is prevented from occurring by exerting pressurization in a direction in which inner rings 135a and 235a of the two rolling bearings 155 and 235 are repulsive. Or, rattling is prevented from occurring in a way that a power is transmitted through a key 124 made of resin interposed between the shaft 123 and a rotor 121. These constitutions reduce the generation of noise. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vane rotary type vacuum pump used without oil.

  Conventionally, in a vane rotary type vacuum pump used without oil of this type, the rotor can be freely moved in the axial direction with respect to the shaft. (For example, refer to Patent Document 1).

  FIG. 5 is a side view of a conventional vane rotary type rotary vacuum pump described in Patent Document 1, and a part of the rotary vacuum pump is shown in cross section. FIG. 6 is an enlarged view around the rotor of FIG. It is sectional drawing of the principal part shown. 5 and 6, the casing of the pump mechanism unit includes a flat base 331, a cylinder member 60 positioned on the other surface side of the base 331, and a lid member 70 that sandwiches the cylinder member 60 together with the base 331, Specific spacer members 500, 500 ′ are arranged between the rotor 80 and the casing, in particular, at both end surfaces of the rotor 80.

  The rotary drive shaft 32 that supports the rotor 80 has a surface portion that is partially cut into a D-shaped cross section, and is key-coupled to the center hole of the rotor 80 that fits into it. Therefore, the rotor 80 can move in the axial direction on the rotational drive shaft 32, but is integral with the rotational drive shaft 32 in the rotational direction.

The spacer members 500 and 500 ′ function as a stopper for the rotor 80 that attempts to move in the axial direction while ensuring an appropriate clearance between the rotor 80 and the casing.
JP 2002-195178 A

  However, such a conventional configuration has a problem that when the rotor rotates, the rotor rattles in the gap between the center hole and the shaft, and noise increases. In addition, the shaft supported by the rolling bearing is also configured to be able to move freely in the axial direction within the range of the looseness of the rolling bearing, and noise is similarly caused by the shaft rattling in the axial direction within the rolling bearing. It had the problem of becoming larger.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a vane rotary type vacuum pump that can suppress noise during operation even if there are gaps in the assembly of components constituting the pump mechanism. To do.

  In order to solve the above-described conventional problems, the vane rotary type vacuum pump of the present invention supports the shaft with the first and second rolling bearings, and the first rolling bearing press-fits and fixes the shaft to the inner ring. The inner ring of the second rolling bearing is inserted into the inner ring with a clearance fit, and the inner ring of the second rolling bearing and the shaft are engaged by a spring, so that the inner ring of the first rolling bearing and the second ring are engaged with each other. The configuration is such that a pressurizing force that repels the inner ring of the rolling bearing in the axial direction is applied.

As a result, the shaft receives the force of the spring and is pressed in the direction of the first rolling bearing, and the inner ring of the first rolling bearing and the inner ring of the second rolling bearing are pushed in opposite directions by the force of the spring. Therefore, there is no gap between the inner ring and the outer ring in the rolling bearing, the shaft and the rolling bearing do not rattle during operation, and noise is reduced.

  The vane rotary vacuum pump of the present invention is configured to transmit power by interposing a resin key between the shaft and the rotor.

  As a result, even if there is a gap between the central hole of the rotor of the pump mechanism and the shaft, the impact sound generated by rattling during operation is mitigated by the resin key, and the noise is reduced.

  The vane rotary vacuum pump of the present invention can reduce noise during operation by reducing rattling noise generated from the gap of the pump mechanism.

  According to a first aspect of the present invention, a cylindrical rotor is disposed in a cylinder having a cylindrical inner wall in a state of being eccentric from the central axis of the cylinder, and the rotor is provided with a plurality of grooves in the direction of the central axis. A plate-like vane made of a self-lubricating material is fitted in a slidable state, and a front plate and a rear plate are arranged on the end face of the cylinder so as to sandwich the rotor and vane, thereby providing a plurality of pump spaces. In the vane rotary type vacuum pump in which a shaft is provided at the center of the rotor to form a pump mechanism and a motor is disposed on the opposite side of the rear plate from the pump mechanism to drive the shaft. Provided with a first rolling bearing, a second rolling bearing provided in a motor casing for housing the motor, the shaft being supported by these first and second rolling bearings, The bearing is fixed by press-fitting the shaft into the inner ring, and the shaft is inserted into the inner ring of the second rolling bearing with a clearance fit, and the inner ring of the second rolling bearing and the shaft are engaged by a spring. Thus, by applying a pressurizing force that causes the inner ring of the first rolling bearing and the inner ring of the second rolling bearing to repel each other in the axial direction, the shaft receives the force of the spring and receives the force of the first rolling bearing. Since the inner ring of the first rolling bearing and the inner ring of the second rolling bearing are pushed in opposite directions by the force of this spring, there is no gap between the inner ring and the outer ring in the rolling bearing. The shaft and the rolling bearing do not rattle, and noise can be reduced.

  In particular, the second invention is the vane rotary type vacuum pump according to the first invention, wherein the outer ring of the first rolling bearing is fixed to the rear plate by press-fitting or fixed with an adhesive. Since the outer ring of the bearing is in close contact with the rear plate, there is no gap between the rolling bearing and the rear plate. As a result, there is no air leakage from the motor to the pump mechanism through the gap. (Performance) can be increased.

  According to a third aspect of the invention, in particular, in the vane rotary type vacuum pump of the first or second aspect, the outer ring of the second rolling bearing is fixed to the motor casing by press-fitting or adhesive. Since the outer ring of the second rolling bearing is in close contact with the motor casing, there is no slip between the outer ring and the motor casing. As a result, there is no wear in the housing part of the second rolling bearing and the life of the vacuum pump is extended. can do.

According to a fourth aspect of the present invention, a cylindrical rotor is disposed in a cylinder having a cylindrical inner wall in a state of being eccentric from the central axis of the cylinder, and the rotor is provided with a plurality of grooves in the direction of the central axis. A plate-like vane made of a self-lubricating material is fitted in a slidable state, and a front plate and a rear plate are arranged on the end face of the cylinder so as to sandwich the rotor and the vane, thereby providing a plurality of pump spaces. In a vane rotary vacuum pump in which a shaft is provided at the center of the rotor to form a pump mechanism, and a motor is disposed on the opposite side of the rear plate from the pump mechanism to drive the shaft. By using a resin key in between to transmit power, even if there is a gap between the center hole of the rotor of the pump mechanism and the shaft, there will be rattling during operation. Thus will the impact sound generated is reduced by the resin key can lower the resulting noise.

  According to a fifth aspect of the invention, in particular, in the vane rotary type vacuum pump according to the fourth aspect of the invention, the resin key is composed of a disk and a plurality of columnar protrusions provided on the outer peripheral portion thereof. By adopting a configuration that is arranged between the plates, the force is reliably transmitted from the mechanical shaft to the rotor by the keys of the plurality of columnar protrusions, and the impact is received by sharing the impact with the plurality of resin keys. The life of the resin key can be extended by relaxing.

  In the sixth invention, in particular, in the vane rotary type vacuum pump of the fourth or fifth invention, the resin key is made of polyoxymethylene (polyacetal resin) to increase the mechanical strength of the resin key. In addition, the resin key can be injection-molded, and as a result, an easy-to-make vacuum pump can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a vane rotary type vacuum pump according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view of a pump mechanism part of the vane rotary type vacuum pump according to Embodiment 1.

  1 and 2, the vane rotary vacuum pump of the present invention includes a pump mechanism unit 100, a motor unit 200 that drives the pump mechanism unit 100, and a cooling circuit unit 300 that cools the motor unit 200. Yes.

  The pump mechanism unit 100 includes a cylinder 111 having a cylindrical inner wall, a cylindrical rotor 121, a vane 131 made of a self-lubricating material, and a front plate 141 and a rear plate that sandwich these to form a plurality of pump spaces 161. 151. The rotor 121 is arranged in a state of being eccentric from the central axis of the cylinder 111, and the vane 131 is slidably fitted in a plurality of grooves 122 provided in the direction of the central axis of the rotor 121. On both sides thereof, a front plate 141 and a rear plate 151 are arranged adjacent to each other to form a pump space 161. In addition, a mechanical shaft 123 is provided at the central axis of the rotor 121, and the rotor 121 rotates as the mechanical shaft 123 rotates, and accordingly the vane 131 moves inside the rotor groove 122. During operation, the tip of the vane 131 slides in contact with the inner wall of the cylinder 111, so that the pump space 161 is partitioned, and suction, compression, and discharge are repeated to perform the pump function.

  In FIG. 2, both the suction port 142 and the discharge port 143 are provided on the front plate 141, and the working fluid sucked from the suction port 142 reaches the pump space 161, is confined by the vane 131, and then compressed with rotation. The air is exhausted from the discharge port 143. In this cycle, in order to suppress the so-called vane jumping phenomenon in which the vane 131 moves away from the inner wall of the cylinder 111, a back pressure groove 144 is provided in the front plate 141, and pressure is applied to the vane back surface 132 of the vane 131 to force In particular, the vane tip is pressed against the inner wall of the cylinder 111. The back pressure groove 144 is divided into a plurality of portions, and an optimum back pressure is applied at each rotational position by changing the back pressure according to the rotational phase of the vane 131.

  The motor unit 200 includes a stator 211, a motor rotor 221, and a motor casing 231. The stator 211 is sandwiched between the end plate 151 and the motor casing 231 from both sides, and includes a motor rotor 221 therein. A motor shaft 222 is provided on the central axis of the motor rotor 221, one end of which is supported by a first rolling bearing 155 provided in the rear plate 151, and the other end is a second provided in the motor casing 231. Are supported by a rolling bearing 235. As the rolling bearing used here, a grease-enclosed ball bearing is desirable. Further, the motor shaft 222 and the mechanical shaft 123 are integrated shafts, and the rotation of the motor rotor 221 directly becomes the rotation of the rotor 121, so that no power transmission loss occurs.

  The cooling circuit unit 300 includes a cooling fan 311 and an air guide 321. A cooling fan 311 is attached to the end of the motor shaft 222 opposite to the pump mechanism, and the periphery of the cooling fan 311 is surrounded by an air guide 321 to prevent wind from being dispersed. In addition, a plurality of through holes are provided in the axial end surface of the motor casing 231, and the motor unit 200 is cooled by forming a wind circuit.

  Corresponding to the first invention, the first rolling bearing 155 has the motor shaft 222 press-fitted and fixed to the inner ring 155a, and the motor shaft 222 is fitted into the inner ring 235a of the second rolling bearing 235 with a gap. It is inserted in the state of. Further, a spring 241 is installed between the inner ring 235a of the second rolling bearing 235 and the stopper 223 provided on the motor shaft 222, and the inner ring 155a of the first rolling bearing 155 and the second rolling bearing 235 are arranged. A pressure is applied to repel the inner ring 235a in the axial direction. In this embodiment, a coil spring is used as the spring 241; however, a wave spring may be used.

  With this configuration, the motor shaft 222 (mechanical shaft 123) is always pressed in the direction of the pump mechanism 100 by the force of the spring 241 and does not rattle in the axial direction during operation. At the same time, due to the force of the spring 241, the inner ring 155a of the first rolling bearing 155 is pressed toward the pump mechanism 100, while the inner ring 235a of the second rolling bearing 235 is pressed toward the cooling circuit 300, Shaking of the ball existing between the inner and outer rings is suppressed. As described above, the motor shaft 222 and the first and second rolling bearings 155 and 235 do not rattle during operation, and an effect that noise is reduced can be obtained.

  Further, in the pump mechanism unit 100, the pressure in the pump space 161 is lower than the atmospheric pressure due to the rotation of the rotor 12, so that the air present in the vicinity of the motor unit 200 is a gap around the outer ring 155b of the first rolling bearing 155, After that, it tries to flow into the pump space 161 through a gap between the mechanical shaft 123 and the center hole of the rear plate 151. At this time, in the present embodiment, the first rolling bearing 155 is constantly pushed toward the pump mechanism unit 100 in the rear plate 151, so that the end surface of the outer ring 155b is in close contact with the rear plate 151, and the air Inflow is cut off. Thereby, the amount of air sucked from the suction port 142 is increased, and the volumetric efficiency (performance) of the vacuum pump is increased. Further, since the air in the vicinity of the motor unit 200 does not flow, the odorous substance contained in the motor stator 211 does not flow into the pump space 161, and the problem of the odor of the air discharged from the discharge port 143 is also obtained. .

Corresponding to the second invention, the outer ring 155b of the first rolling bearing 155 is fixed to the rear plate 151 by press fitting or adhesive. As a result, the outer ring 155b of the first rolling bearing 151 comes into close contact with the rear plate 155, so that there is no gap between the first rolling bearing 155 and the rear plate 151. As a result, the motor mechanism 200 and the pump mechanism section are passed through the gap. Air leakage into 100 is eliminated, and the volumetric efficiency (performance) of the vacuum pump can be further increased. Moreover, the problem of the odor resulting from the motor stator part 211 can be solved similarly to the above.

  Corresponding to the third aspect of the invention, the outer ring 235b of the second rolling bearing 235 is fixed to the motor casing 231 by press-fitting or adhesive. As a result, the outer ring 235b of the second rolling bearing 235 comes into close contact with the motor casing 235, so that there is no slip between the outer ring 235b and the motor casing 235. As a result, wear of the storage portion of the second rolling bearing 235 is eliminated. As a result, the life of the vacuum pump can be extended.

(Embodiment 2)
3 and 4 are cross-sectional views of the vane rotary type vacuum pump according to the second embodiment of the present invention.

  This embodiment relates to the fourth to sixth inventions. In the vane rotary vacuum pump shown in the first embodiment, power is transmitted by interposing a resin key 124 made of resin between the mechanical shaft 123 and the rotor 121. It is configured to do. In general, a minute gap is provided between the center hole of the rotor 121 of the pump mechanism 100 and the mechanical shaft 123 so that the rotor 121 can freely move in the axial direction. Impact sound is generated by minute vibrations (shaking) around the shaft 123. However, in this embodiment, since the resin key 124 is interposed, the impact sound is relieved by the resin, and as a result, the noise can be reduced.

  Corresponding to the fifth aspect of the invention, as shown in FIG. 4, the resin key 124 is composed of a disk 125 and three columnar protrusions 126 provided on the outer periphery thereof. It is arranged between the end face and the front plate 151. With this configuration, force is reliably transmitted from the mechanical shaft 123 to the rotor 121 by the keys of the three columnar protrusions 126, and the three resin keys share and receive the impact, thereby reducing the impact. The life of the resin key 124 can be extended. The shape of the resin key 124 is not limited to the above-mentioned disk + plurality of columnar projections, and even if it is a normal rectangular parallelepiped key (parallel key), if the material is resin, the noise reduction effect is achieved. Is obtained.

Corresponding to the sixth invention, the material of the resin key 124 is polyoxymethylene (polyacetal resin). For example, Duracon (registered trademark) of Polyplastics Co., Ltd. is suitable, and among polyoxymethylenes, an acetal copolymer is desirable because it is thermally stable. As a result, the mechanical strength of the resin key can be increased, the resin key can be injection-molded, and a vacuum pump that is easy to manufacture can be provided.
Of course, the invention of Embodiment 1 and the invention of Embodiment 2 can be combined, and noise can be further reduced.

  As described above, the vane rotary type vacuum pump according to the present invention aims to reduce noise by preventing rattling of the shaft and the rolling bearing and reducing impact noise caused by rattling between the rotor and the shaft. Therefore, it can also be applied to uses such as household health appliances and medical treatment appliances.

Sectional drawing of the vane rotary type vacuum pump in Embodiment 1 of this invention Sectional drawing of the pump mechanism part of the vane rotary type vacuum pump in Embodiment 1 of this invention Sectional drawing of the vane rotary type vacuum pump in Embodiment 2 of this invention The perspective view of the key and its fitting part of the vane rotary type | mold vacuum pump in Embodiment 2 of this invention It is the figure which looked at the conventional vane rotary type rotary vacuum pump from the side, and the figure which showed a part in section Sectional drawing of the principal part which expands and shows the rotor periphery of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Pump mechanism part 111 Cylinder 121 Rotor 122 Rotor groove 123 Mechanical shaft 124 Resin key 125 Disk 126 Columnar protrusion 131 Vane 141 Front plate 151 Rear plate 155 1st rolling bearing 155a Inner ring 155b Outer ring 161 Pump space 200 Motor part 222 Motor shaft 231 Motor casing 235 Second rolling bearing 235a Inner ring 235b Outer ring 241 Spring

Claims (6)

A cylindrical rotor is disposed in a cylinder having a cylindrical inner wall in an eccentric state from the central axis of the cylinder, and the rotor is provided with a plurality of grooves in the direction of the central axis, and these grooves are self-lubricated. A plate-like vane made of a flexible material is slidably fitted, and a front plate and a rear plate are arranged on the end face of the cylinder so as to sandwich the rotor and vane to form a plurality of pump spaces. A pump mechanism portion is provided with a shaft at the center of the rotor, a motor is disposed on the opposite side of the rear plate from the pump mechanism portion, and the motor drives the shaft, thereby the pump space. Is a vane rotary vacuum pump that generates expansion and contraction,
A first rolling bearing is provided in the rear plate, a second rolling bearing is provided in a motor casing that houses the previous motor, the shaft is supported by the first and second rolling bearings, and the first rolling bearing is provided. In the rolling bearing, the shaft is press-fitted and fixed to the inner ring, the shaft is inserted into the inner ring of the second rolling bearing with a clearance fit, and the inner ring and the shaft of the second rolling bearing are spring-loaded. The vane rotary vacuum pump is applied by applying a pressurizing force that causes the inner ring of the first rolling bearing and the inner ring of the second rolling bearing to repel each other in the axial direction. 2. The vane rotary vacuum pump according to claim 1, wherein an outer ring of the first rolling bearing is fixed to the rear plate by press-fitting or adhesive. The vane rotary vacuum pump according to claim 1 or 2, wherein an outer ring of the second rolling bearing is fixed to the motor casing by press-fitting or adhesive. A cylindrical rotor is disposed in a cylinder having a cylindrical inner wall in an eccentric state from the central axis of the cylinder, and the rotor is provided with a plurality of grooves in the direction of the central axis, and these grooves are self-lubricated. A plate-like vane made of a flexible material is slidably fitted, and a front plate and a rear plate are arranged on the end face of the cylinder so as to sandwich the rotor and vane to form a plurality of pump spaces. A pump mechanism portion is provided with a shaft at the center of the rotor, a motor is disposed on the opposite side of the rear plate from the pump mechanism portion, and the motor drives the shaft, thereby the pump space. Is a vane rotary vacuum pump that generates expansion and contraction,
A vane rotary vacuum pump in which power is transmitted by interposing a resin key made of resin between the shaft and the rotor. 5. The vane rotary vacuum pump according to claim 4, wherein the resin key includes a disk and a plurality of columnar protrusions provided on an outer periphery of the disk, and the resin key is disposed between an end surface of the shaft and the front plate. . 6. The vane rotary vacuum pump according to claim 4, wherein the resin key is made of polyoxymethylene (polyacetal resin).

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