JP2012225328A - Scroll type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scroll type compressor for preventing flaking in a part in contact with a bush of a radial bearing, while preventing an increase in rolling resistance of a spiral wall of a scroll member to be paired even in high-speed rotation.SOLUTION: In this scroll type compressor, the bush 23 is fitted around an eccentric shaft 17 arranged in an end part of a driving shaft 12, and the bush 23 is relatively rotatably supported by the radial bearing 24 arranged in a boss part 22b formed on a back face of a turning scroll member 22, and the bush 23 is provided with a balance weight 32 integrated with the bush. When the bush 23 tilts, an outer peripheral surface of the bush is brought into contact with the radial bearing 24 only on the end part side provided with the balance weight 32. Specifically, a clearance A between the eccentric shaft 17 and an inner peripheral surface of an eccentric hole 23a of the bush 23 is formed smaller than a clearance C between the radial bearing 24 and the outer peripheral surface of the bush 23.

Description

  The present invention relates to a scroll compressor used in a refrigeration cycle of a vehicle air conditioner, and more particularly to an eccentric shaft provided at an end portion of a drive shaft mounted on a boss portion of an orbiting scroll member via a bush and a radial bearing. The present invention relates to a scroll-type compressor having a configuration to do so.

  The scroll type compressor has a fixed scroll member having an end plate and a spiral wall standing upright from the end plate, and has an end plate opposed to the fixed scroll member and a spiral wall standing upright from the end plate. And a pair of scroll members combined with each of the spiral walls and rotating the orbiting scroll member in a state where rotation is restricted (revolving motion), so that the space between the spiral walls of both scroll members is reduced. The compression chamber formed in the above is moved to the center while reducing the volume to compress the working fluid.

  In such a scroll compressor, the orbiting scroll member has a boss portion formed on the back surface of the end plate, and an eccentric shaft provided at one end of the drive shaft is mounted on the boss portion via a radial bearing. The shaft is supported so as to be able to oscillate (revolve) around the axis of the drive shaft.

  At this time, if there is a clearance between the side surfaces of the scroll walls of both scroll members, the high-pressure gas leaks from the compression chamber on the central side (downstream side) to the outer peripheral side (upstream side), so the compression efficiency is impaired. End up. For this reason, a bush as an intermediate member is disposed between the eccentric shaft of the drive shaft and the radial bearing (bearing portion) provided on the boss portion of the orbiting scroll member, and the compression reaction force acting on the orbiting scroll member is distributed. Using the force, the orbiting scroll member is urged in the radial direction of the fixed scroll member so that the side surface of the spiral wall of the orbiting scroll member abuts on the side surface of the spiral wall of the fixed scroll member without being separated. A mechanism that varies the amount of revolution radius is employed (Patent Documents 1 to 3).

  Among these, the scroll compressor disclosed in Patent Document 1 has a bush 103 attached to the boss portion 102 of the orbiting scroll member 101 as shown in FIG. This is a so-called slide-type bush that is relatively unrotatable with respect to the eccentric shaft 105 provided at one end of the shaft and can move slightly in the radial direction. Further, the eccentric shaft 105 is provided with a curved surface portion 106 so that even if the drive shaft 104 is deformed by the compressive force or centrifugal force of the orbiting scroll member 101, the bearing portion does not cause a single contact. . Further, the publication also discloses a configuration in which the balance weight 107 is provided on the drive shaft 104 at a position shifted in the axial direction from the bush 103.

  As shown in FIG. 7, the scroll compressor disclosed in Patent Document 2 is configured such that an eccentric shaft 112 provided at one end of a drive shaft 111 is connected to a boss portion of an orbiting scroll member 115 via a bush 113 and a radial bearing 114. In the configuration that is pivoted on 117, the balance weight 116 is supported by being press-fitted into the outer peripheral surface of the bush 113, and rotates together with the bush 113. The balance weight 116 extends outward in the radial direction of the boss portion 117 of the orbiting scroll member 115 so that the acting point of the centrifugal force acting on the balance weight 116 is as close as possible to the acting point of the centrifugal force acting on the orbiting scroll member 115. Is provided.

  As shown in FIG. 8, in the scroll compressor disclosed in Patent Document 3, a bush 122 integrally provided with a balance weight 121 is assembled to an eccentric shaft 124 provided at the tip of a drive shaft 123. Is disclosed in which the orbiting scroll member 125 is revolved by pivoting it on a boss portion 126 provided on the rear surface of the orbiting scroll member 125 via a radial bearing 127. The balance weight 121 is provided so as to project outside the boss portion 126 of the orbiting scroll member 125, as in Patent Document 2, but it also projects to the opposite side (motor side) of the orbiting scroll member 125. Since it is provided, the overhang in the radial direction is suppressed, and a device for avoiding an increase in the diameter of the orbiting scroll member 125 is devised.

JP-A-8-42467 JP-A-8-42477 JP 2010-196630 A

  However, in the configuration of Patent Document 1 (FIG. 6), the portion where the balance weight 107 is provided is not the bush 103 but the drive shaft 104, so that the centrifugal force is canceled and the balance is maintained in the entire compressor. However, since it does not act to counteract the centrifugal force that pushes the orbiting scroll member 101 radially outward, the contact load between the spiral wall 101a of the orbiting scroll member 101 and the spiral wall 108a of the fixed scroll member 108 is reduced. This increases the rolling resistance of the spiral walls 101a and 108a at the time of high speed rotation, and the reliability of the spiral walls is impaired.

  Further, in the configuration of FIG. 7 (FIG. 7), since the balance weight 116 is provided so as to protrude outside the boss portion 117, the rotation prevention mechanism 118 is further provided to avoid interference with the balance weight 116. Therefore, the orbiting scroll member 115 is increased in size and hinders downsizing of the compressor. Further, since the weight of the orbiting scroll member 115 becomes heavy, there is also a disadvantage that the balance weight 116 must be increased in order to balance it.

  Furthermore, in the configuration of Patent Document 3 (FIG. 8), the balance weight 121 is provided so as to protrude on the opposite side (motor side) from the orbiting scroll member 125, so the centrifugal force of the balance weight 121 is a radial bearing. It acts on the end of the bush 122 protruding from 127, and the shaft center of the bush 122 tends to tilt with respect to the shaft center of the eccentric shaft 124. For this reason, in order to reduce the inclination of the bush 122, conventionally, the clearance between the radial bearing 127 and the outer peripheral surface of the bush 122 is set as small as possible, and the force that the bush 122 tends to tilt by the radial bearing 127 is used. However, at the time of high-speed rotation, the local contact of the bearing inner ring exceeds the proof stress, and there is a disadvantage that flaking occurs.

  In particular, in a configuration in which a needle bearing is used as the radial bearing, according to the conventional design concept, as shown in FIG. 9A, a gap between the inner peripheral surface of the radial bearing 24 and the outer peripheral surface of the bush 23 is provided. Clearance (in the case of a needle bearing, the clearance between the roller 24a and the outer peripheral surface of the bush 23) C is made as small as possible (C is made smaller than the clearance A between the bush 23 and the eccentric shaft 17). Although designed, the balance weight 32 is provided at the end of the bush 23, and the center of gravity of the balance weight 32 is offset from the center of the eccentric shaft 17 provided at the end of the drive shaft 12, so that FIG. As shown in FIG. 2, the shaft center of the bush 23 is inclined with respect to the shaft center of the eccentric shaft 17, and the centrifugal force of the balance weight 32 in this state causes the bush 23 to Acting on the orbiting scroll member 22 through a fine radial bearing 24. At this time, since the clearance C is formed smaller than the clearance A, two inner surfaces of the radial bearing 24 (the end portion provided with the balance weight 32 are provided to support the bush 23 inclined by the centrifugal force F1 of the balance weight 32. Near [site separated by L1 in the axial direction from the location where the centrifugal force of the balance weight 32 acts] and in the vicinity of the end away from the balance weight 32 [separate L2 in the axial direction from the location where the centrifugal force of the balance weight 32 acts The load (F2, F3) is received at two locations (L2> L1]). For this reason, the load of F2 is increased by the amount of F3 generated, and the local load is received at the portion receiving the load of F2. Becomes remarkably large and flaking tends to occur.

  The present invention has been made in view of such circumstances, and flaking is performed at a contact portion with a bush of a radial bearing while suppressing an increase in rolling resistance of a spiral wall of a scroll member that forms a pair even during high-speed rotation. The main object is to provide a scroll compressor that avoids the occurrence of the above. In addition to this, another object is to reduce the size of the compressor.

  In order to achieve the above object, a scroll compressor according to the present invention is provided with a fixed scroll member that has an end plate and a spiral wall that is erected from the end plate, the movement in the radial direction of the housing being restricted, The orbiting scroll member disposed opposite to the fixed scroll member and having an end plate and a spiral wall erected from the end plate, a drive shaft for transmitting rotational power, and an end portion of the drive shaft, the drive shaft An eccentric shaft provided at a position shifted with respect to the axis of the shaft, a radial bearing fitted in a boss formed on the back surface of the orbiting scroll member, and an eccentric hole into which the eccentric shaft is inserted, A bush that is externally fitted to the eccentric shaft through the eccentric hole and is rotatably supported by the radial bearing, and a balance way that is provided at one end of the bush and is integral with the bush. With the door, when said bushing is inclined, scroll compressor, characterized in that the outer peripheral surface of the bush and so as to abut against the radial bearing only the end portion side of the balance weight is provided.

  Therefore, if the balance weight centrifugal force acts on the portion that is axially displaced from the radial bearing (the end of the bush that protrudes from the radial bearing), the balance weight centrifugal force causes the bush axis to be eccentric. When the bush is tilted, the outer peripheral surface of the bush comes into contact with the radial bearing only at the end side where the balance weight is provided. It becomes possible to avoid a situation in which the end of the bush that moves the local load away from the balance weight abuts against the radial bearing to increase significantly. For this reason, since it becomes possible to reduce the eccentric load which arises in a radial bearing, the proof stress of a radial bearing is raised relatively and generation | occurrence | production of the flaking which arises in the contact part with the outer peripheral surface of the bush of a radial bearing is suppressed. It becomes possible.

  Here, when the bush is tilted, a specific configuration in which the bush is brought into contact with the radial bearing only at the end portion side where the balance weight is provided is as follows: the eccentric shaft and the inner peripheral surface of the eccentric hole provided in the bush. The clearance is A, the fitting length between the eccentric shaft and the inner peripheral surface of the eccentric hole provided in the bush is B, the clearance between the radial bearing and the outer peripheral surface of the bush is C, and the fitting between the radial bearing and the outer peripheral surface of the bush When the length is D, it may be set so that A / B <C / D.

  Further, with the above-described configuration, even if the point at which the centrifugal force of the balance weight acts is shifted in the axial direction from the radial bearing, the offset load (the contact between the bush and the radial bearing) due to the inclination of the bush. (Local load at the contact point) can be suppressed within an allowable range. Therefore, when the anti-rotation mechanism is disposed on the radially outer side of the boss portion of the orbiting scroll member, the balance weight is removed from the orbiting scroll member. You may make it project so that it may protrude positively and may avoid interference with a rotation prevention mechanism.

  According to such a configuration, even when the rotation prevention mechanism is provided close to the outside of the boss portion of the orbiting scroll member, it is possible to provide the balance weight so as to avoid interference with the rotation prevention mechanism. It becomes possible to reduce the outer shape of the rotation prevention mechanism, and thereby to reduce the outer diameter of the orbiting scroll member.

  Further, a needle bearing may be used as the radial bearing. Needle bearings are compact and lightweight, but contact surface pressure becomes excessive when the shaft is in contact with the shaft center of the bearing, so it is not suitable for supporting axial loads and shaft tilt. Since the local load with the bush can be reduced as described above, the proof stress can be relatively increased, and the needle bearing can sufficiently cope with it. For this reason, the weight of the bearing can be reduced, and the radial dimension can be made compact, so that the balance weight can also be reduced in weight.

  As described above, according to the present invention, the eccentric shaft provided at the end of the drive shaft is connected to the radial bearing provided at the boss portion of the orbiting scroll member via the bush provided integrally with the balance weight. When the bush is tilted, the outer peripheral surface of the bush is brought into contact with the radial bearing only at the end side where the balance weight is provided. The local load is not significantly increased at the contact portion between the surface and the radial bearing, and flaking can be avoided at the contact portion between the radial bearing and the bush. For this reason, it is possible to avoid the occurrence of flaking at the contact portion with the bush of the radial bearing while suppressing an increase in rolling resistance of the spiral wall of the scroll member that makes a pair even at high speed rotation. It becomes.

  Further, with the above-described configuration, even when the balance weight is formed to protrude away from the orbiting scroll member, the local load at the contact portion between the outer peripheral surface of the bush and the radial bearing is within an allowable range. Therefore, by forming the balance weight so as to project away from the orbiting scroll member, even if a rotation prevention mechanism is provided close to the outside of the boss, interference with this is avoided. As a result, the outer diameter of the rotation prevention mechanism and the orbiting scroll member can be reduced.

  Furthermore, since it is possible to reduce the local load at the contact portion between the bush and the radial bearing, the radial bearing can be sufficiently accommodated by the needle bearing. The weight of the scroll member can be reduced, and the weight of the balance weight provided for canceling the centrifugal force of the orbiting scroll member can be reduced.

FIG. 1 is a cross-sectional view showing an example of the overall configuration of a scroll compressor according to the present invention. FIG. 2A is a cross-sectional view showing a state in which a bush is externally fitted to an eccentric shaft provided at an end portion of a drive shaft, and this bush is supported by a radial bearing provided at a boss portion of the orbiting scroll member. FIG. 2 (b) is an exploded perspective view of FIG. 2 (a). 3A and 3B are diagrams showing the bush, wherein FIG. 3A is a view seen from one side in the axial direction, FIG. 3B is a side sectional view of the bush, and FIG. 3C is the other side in the axial direction. It is the figure seen from. 4A and 4B are diagrams showing the balance weight, where FIG. 4A is a view seen from one side in the axial direction, FIG. 4B is a side sectional view of the balance weight, and FIG. 4C is the other side in the axial direction. It is the figure seen from the side. FIG. 5 shows a state in which an eccentric shaft provided at the end of the drive shaft is mounted on a radial bearing provided at the boss portion of the orbiting scroll member via a bush having a balance weight provided at one end. It is an enlarged view shown, (a) is a figure which shows the state which the drive shaft is not rotating, (b) is a figure which shows the state in which the drive shaft rotated and the bush inclined. FIG. 6 is a cross-sectional view showing a conventional scroll compressor. FIG. 7 is a cross-sectional view showing another conventional scroll compressor. FIG. 8 is a cross-sectional view showing still another conventional scroll compressor. FIG. 9 shows a conventional example in which an eccentric shaft provided at an end portion of a drive shaft is mounted on a radial bearing provided at a boss portion of an orbiting scroll member via a bush having a balance weight provided at one end portion. It is an enlarged view which shows a state, (a) is a figure which shows the state which the drive shaft is not rotating, (b) is a figure which shows the state in which the drive shaft rotated and the bush inclined.

The scroll compressor according to the present invention will be described below with reference to the drawings.
In FIG. 1, a scroll compressor 1 is an electric compressor suitable for a refrigeration cycle using a refrigerant as a working fluid, and a compression mechanism 3 is arranged on the left side in the figure in a housing 2 made of an aluminum alloy. In addition, an electric motor 4 for driving the compression mechanism 3 is disposed on the right side in the drawing. In FIG. 1, the right side in the drawing is the front side of the compressor 1, and the left side in the drawing is the rear side of the compressor.

  The housing 2 includes a compression mechanism housing member 2 a that houses the compression mechanism 3, an electric motor housing member 2 b that houses the electric motor 4 that drives the compression mechanism 3, and an inverter that houses an inverter device (not shown) that drives and controls the electric motor 4. The housing member 2c is positioned with the positioning pins 7 and fastened in the axial direction with the fastening bolts 8.

A partition wall 10 formed integrally with a shaft support portion 9a is provided on the side of the motor housing housing member 2b that faces the compression mechanism housing housing member 2a, and is opposed to the motor housing housing member 2b of the inverter housing housing member 2c. A partition wall 11 in which a shaft support portion 9b is integrally formed is provided on the side to be supported, and a drive shaft 12 is rotatably supported by the shaft support portions 9a and 9b of the partition walls 10 and 11 via bearings 13 and 14, respectively. Yes. The partition wall 10, 11 formed in the motor housing housing member 2 b and the inverter housing housing member 2 c has a compression mechanism housing portion 15 a in which the inside of the housing 2 houses the compression mechanism 3 from the rear, and a motor in which the motor 4 is housed. It is partitioned into a housing portion 15b and an inverter housing portion 15c that houses the inverter device.
In this example, the inverter accommodating portion 15c is defined by fixing the lid body 16 to the inverter accommodating housing member 2c with a bolt or the like (not shown).

  The compression mechanism 3 is of a scroll type having a fixed scroll member 21 and an orbiting scroll member 22 disposed to face the fixed scroll member 21, and the fixed scroll member 21 is allowed to move in the axial direction with respect to the housing 2. The movement in the radial direction is restricted by the positioning pin 28, a disc-shaped end plate 21a, and a cylinder that is provided over the entire periphery along the outer edge of the end plate 21a and is erected forward. An outer peripheral wall 21b and a spiral spiral wall 21c extending forward from the end plate 21a inside the outer peripheral wall 21b.

  The orbiting scroll member 22 is composed of a disc-shaped end plate 22a and a spiral spiral wall 22c erected rearward from the end plate 22a, and is erected on the back surface of the end plate 22a. The eccentric shaft 17 provided at the rear end portion of the drive shaft 12 and eccentrically with respect to the shaft center of the drive shaft 12 is supported by the boss portion 22b via the bush 23 and the radial bearing 24. It is provided so that it can revolve around the axis.

  The fixed scroll member 21 and the orbiting scroll member 22 are meshed with each other with respective spiral walls 21c and 22c. The end plate 21a and the spiral wall 21c of the fixed scroll member 21 and the end plate 22a and the spiral of the orbiting scroll member 22 are engaged with each other. A compression chamber 25 is defined in a space surrounded by the wall 22c.

  Further, a thin plate-shaped annular thrust trace 26 is sandwiched between the outer peripheral wall 21 b of the fixed scroll member 21 and the partition wall 10, and the fixed scroll member 21 and the partition wall 10 are interposed via the thrust trace 26. It is faced.

  The thrust trace 26 is formed of a material excellent in wear resistance, and a central hole through which a boss portion 22b of the orbiting scroll member 22 and an Oldham ring 27 (to be described later) are inserted is formed in the center. The fixed scroll member 21, the thrust trace 26, and the motor housing housing member 2 b are defined in the radial direction by positioning pins 28 that are inserted into pin insertion holes formed in the thrust trace 26.

  The shaft support portion 9a formed integrally with the partition wall 10 of the electric motor housing member 2b has a through hole in the center, and the inner surface thereof is formed in a stepwise manner toward the thrust trace 26, From the front side farthest from the thrust trace 26, the bearing housing 31 in which the bearing 13 is housed, is integrally formed with the bush 23, or is externally fitted to the bush so as not to rotate relative to the bush 23. A weight accommodating portion that accommodates a balance weight 32 that rotates with the rotation of the drive shaft 12 (in this example, the balance weight 32 is formed separately from the bush 23 and is fitted on the bush 23 so as not to rotate relative to the bush 23). 33, formed following the weight accommodating portion 33, and prevents the orbiting scroll member 22 from rotating with the orbiting scroll member 22. Oldham accommodating portion 34 for accommodating the Oldham ring 27 are formed.

  Therefore, the orbiting scroll member 22 is rotated by the rotation of the drive shaft 12, but revolves around the axis of the drive shaft 12 while the rotation is restricted by the Oldham ring 27.

  Between the outer peripheral wall 21b of the fixed scroll member 21 and the outermost peripheral portion of the spiral wall 22c of the orbiting scroll member 22, the suction chamber for sucking the refrigerant introduced from the suction port 40 described later through the suction passage 45. 35 is formed, and behind the fixed scroll member 21 in the housing, the refrigerant gas compressed in the compression chamber 25 is discharged through a discharge hole 36 formed substantially at the center of the fixed scroll member 21. A chamber 37 is defined between the rear end wall of the compression mechanism housing member 2a. The refrigerant gas discharged into the discharge chamber 37 is pumped to an external refrigerant circuit through the discharge port 38.

  On the other hand, the stator 41 and the rotor 42 which comprise the electric motor 4 are provided in the electric motor accommodating part 15b formed in the part ahead of the partition wall 10 in the housing 2. FIG. The stator 41 includes a cylindrical iron core 43 and a coil 44 wound around the iron core 43, and is fixed to the inner surface of the housing 2 (electric motor housing member 2b). The drive shaft 12 is fixedly mounted with a rotor 42 made of a magnet rotatably accommodated inside the stator 41, and the rotor 42 is rotated by a rotating magnetic force formed by the stator 41. It is designed to rotate. The stator 41 and the rotor 42 constitute an electric motor 4 composed of a brushless DC motor.

  A suction port 40 for sucking refrigerant gas into the motor housing portion 15b is formed on the side surface of the housing 2 (motor housing housing member 2b), and a gap between the stator 41 and the housing 2 (motor housing housing member 2b). In addition, the refrigerant flowing from the suction port 40 into the motor housing portion 15b is guided to the suction chamber 35 through a hole formed in the partition wall 10 and a gap formed between the fixed scroll member 21 and the housing 2. A suction path 45 is configured.

  The inverter device housed in the inverter housing member 2c is electrically connected to the stator 41 via a terminal (airtight terminal) 60 attached to a through hole 61 formed in the partition wall 11, and is connected to the motor 4. Power is supplied from the inverter device.

  Therefore, when the rotor 42 rotates and the drive shaft 12 rotates by supplying power to the electric motor 4, the orbiting scroll member 22 rotates around the eccentric shaft 17 in the compression mechanism 3. It revolves around the axis of the member 21. At this time, since the orbiting scroll member 22 is prevented from rotating by the rotation preventing mechanism including the Oldham ring 27, only the revolving motion is allowed.

  Due to the revolving motion of the orbiting scroll member 22, the compression chamber 25 moves while gradually reducing the volume from the outer peripheral side of the scroll walls 21c, 22c of both scroll members to the center side, so that the suction chamber 35 sucks into the compression chamber 25. The compressed refrigerant gas is compressed, and the compressed refrigerant gas is discharged into the discharge chamber 37 through the discharge hole 36 formed in the end plate 21 a of the fixed scroll member 21. Then, it is sent to the external refrigerant circuit through the discharge port 38.

  In the above configuration, the bush 23 described above has a columnar shape as shown in FIGS. 2 and 3 and extends in the axial direction at a position shifted in the radial direction from the axial center, and the eccentric shaft. 17 is formed, and a concave portion 23b having a diameter larger than that of the eccentric hole 23a is formed at the end portion on the orbiting scroll member side. A weight fitting allowance 23c for reducing the outer diameter and fitting the balance weight 32 is formed.

As shown in FIG. 4, the balance weight 32 includes an annular fitting portion 32a, and a fan-shaped weight body 32b integrally formed on the periphery of the fitting portion 32a over a predetermined angular range. The fitting portion 32a is externally fitted to the outer periphery of the weight fitting allowance 23c of the bush 23 by, for example, press fitting, and rotates together with the bush 23.
This balance weight is formed so as to project closer to the orbiting scroll member and also to extend away from the orbiting scroll member, thereby shortening the radial dimension and preventing interference with the Oldham ring 27. The required mass is secured while avoiding it.

  The eccentric shaft 17 has a cylindrical shape in which an annular groove 17a is formed in the vicinity of one end, and an annular groove 17a is formed in a fitting hole 12a formed in an end surface of the drive shaft 12 facing the orbiting scroll member 22. The end on the opposite side is press-fitted and fixed, and the end on the annular groove side is inserted into the eccentric hole 23a of the bush 23 so as to be relatively rotatable and protruded into the recessed portion 23b and protruded into the recessed portion 12b. The bush 23 is attached to the portion by fitting the circlip 29 into the annular groove 17a. For this reason, the bush 23 is attached so as to be rotatable relative to the eccentric shaft 17 while restricting movement of the eccentric shaft 17 in the axial direction.

The radial bearing 24 fitted in the boss portion 22b of the orbiting scroll member 22 is constituted by a needle bearing in which a large number of needle-like rollers 24a are arranged at equal intervals in the circumferential direction, and the bush 23 is interposed between the outer peripheral surface and the bush 23. A predetermined clearance is provided so as to allow relative rotation.
In this example, the radial bearing 24 has 14 rollers, the length of the roller portion (the axial fitting length with the outer peripheral surface of the bush 23) is set to 10 mm, and the roller diameter is set to 2.5 mm. Further, the fitting length in the axial direction between the bush and the eccentric shaft is set to 15 mm, and the diameter of the eccentric shaft is set to 6 mm.

  By the way, according to the conventional general design method, the radial bearing and the member supported by the radial bearing (in this embodiment, the bush) are in contact with each other in a state as parallel as possible to allow for clearance of the member. Is usually set as small as possible. That is, the radial bearing 24 using a needle bearing is light and compact, but is not suitable for supporting an axial load or a shaft inclination. The common sense in design is to reduce the eccentric load with the needle by suppressing the inclination of the bush by managing to the same.

However, since the balance weight 32 is attached to one end portion of the bush 23 in a portion protruding in the axial direction from the radial bearing 24, the shaft center of the bush 23 is made eccentric by the centrifugal force of the balance weight 32 (drive shaft 12). ) To be tilted with respect to the axis. For this reason, if the inclination of the bush 23 is compensated by reducing the clearance between the outer peripheral surface of the bush 23 and the radial bearing 24, as described above, the bush 23 is moved to the radial bearing 24 at two different locations in the axial direction. There is an inconvenience that flaking occurs due to a significant increase in the offset load at the abutting portion of the bush 23 on the end side where the balance weight 32 of the bush 23 is provided.
For this reason, in the present invention, as shown in FIG. 5 (a), it is inserted into the eccentric hole 23a in order to reduce the local load (eccentric load) on the end portion side where the balance weight of the bush is provided. The clearance A between the outer peripheral surface of the eccentric shaft 17 and the inner peripheral surface of the eccentric hole 23a is set to be smaller than the clearance C between the outer peripheral surface of the bush 23 and the inner peripheral surface of the radial bearing 24. Yes.

More specifically, the clearance between the outer peripheral surface of the eccentric shaft 17 and the inner peripheral surface of the eccentric hole 23a provided in the bush 23 is A, and the clearance between the outer peripheral surface of the eccentric shaft 17 and the inner peripheral surface of the eccentric hole 23a is When the fitting length is B, the clearance between the outer peripheral surface of the bush 23 and the inner peripheral surface of the radial bearing 24 is C, and the fitting length between the outer peripheral surface of the bush 23 and the inner peripheral surface of the radial bearing 24 is D. A = 6-22 μm, C = 24-48 μm,
A / B <C / D
It is set to become.

  Therefore, in such a configuration, the center of gravity of the balance weight 32 provided at the end of the bush 23 protruding from the radial bearing 24 is displaced from the center of the eccentric shaft 17 (the centrifugal force of the balance weight). 5 acts on the end of the bushing 23 protruding from the radial bearing 24), the axis of the bushing 23 is tilted with respect to the axis of the eccentric shaft 17, as shown in FIG. In this state, the outer peripheral surface of the bush 23 comes into contact with the radial bearing 24, and the centrifugal force of the balance weight 32 acts on the orbiting scroll member 22 via the bush 23 and the radial bearing 24. Offset power. At this time, the clearance A between the outer peripheral surface of the eccentric shaft 17 inserted into the eccentric hole 23 a and the inner peripheral surface of the eccentric hole 23 a is between the outer peripheral surface of the bush 23 and the inner peripheral surface of the radial bearing 24. Since the clearance is set to be smaller than the clearance C, the inclination of the bush 23 is regulated by the eccentric shaft 17 (mainly supported by the eccentric shaft 17), and comes into contact with the radial bearing 24 only at one place (the outer periphery of the bush 23). The surface abuts only on the end side where the balance weight 32 is provided, and does not abut on the radial bearing on the end side away from the balance weight 32). For this reason, since F3 (shown in FIG. 9) does not occur, the load F2 acting on the portion that comes into contact with the radial bearing 24 on the end side where the balance weight 32 is provided is not significantly increased. No, it is almost the same size as F1.

However, in actual operation, the force of the component on the near side to the back side is applied to the paper surface by the compression reaction force accompanying the compression in the compression chamber 25 between the orbiting scroll member 22 and the fixed scroll member 21. The bush 23 and the radial bearing 24 come into contact with each other at the point where the resultant force acts. For this reason, in the conventional form, since forces in the opposite directions of F3 and F2 act at two locations on the front side and the rear side of the bush 23, the contact portion is twisted three-dimensionally. In this case, since the load of F3 does not act, such torsional contact is suppressed.
In the above-described configuration, the inclination of the bush 23 is supported by the outer peripheral surface of the eccentric shaft 17 and the fitting portion of the eccentric hole 23a provided in the bush 23. Therefore, the eccentric shaft 17 and the eccentric hole 23a are supported. However, since the bush 23 does not rotate relative to the eccentric shaft 17, no slip or rolling occurs in the contact portion. There is no risk of flaking or wear.

  As described above, in the general design method, C is managed by processing the outer peripheral surface of the bush 23 according to the dimension of the inner peripheral surface of the radial bearing 24 (so-called matching processing). In the above-described configuration, since it is not necessary to manage C to be small, matching processing is omitted. Here, the matching process can be applied to the clearance management of A (the outer peripheral surface of the eccentric shaft 17 is processed in accordance with the dimension of the inner peripheral surface of the eccentric hole 23a), and A = 6 to 12 μm. In this way, the inclination of the bush supported by A can be further reduced without increasing the number of processing steps as compared with the prior art.

  Therefore, it is possible to reduce the unbalanced load acting on the radial bearing 24 (roller 24a), and even if the bush 23 comes into contact with the roller 24a of the radial bearing 24 and locally contacts, flaking is generated. It becomes possible to suppress the relative strength of the radial bearing 24 (there is no need to increase the size of the radial bearing 24 in order to ensure the strength of the radial bearing 24).

  Further, in the above-described configuration, the balance weight 32 is formed so as to protrude in a direction away from the orbiting scroll member 22, so that it is possible to suppress the length of the balance weight in the radial direction and to rotate the balance weight 32. The balance weight 32 can be provided so as not to interfere with the prevention mechanism (Oldham ring 27). For this reason, an increase in the diameter of the Oldham ring 27 can be avoided, and the outer diameter of the orbiting scroll member can be reduced.

  Furthermore, in the above-described configuration, since a needle bearing is used as the radial bearing 24, the weight of the bearing itself can be reduced, and the radial dimension can be reduced. It is possible to reduce the weight of the balance weight.

DESCRIPTION OF SYMBOLS 1 Scroll type compressor 2 Housing 21 Fixed scroll member 21a End plate 21c Swirl wall 22 Orbiting scroll member 22a End plate 22b Boss part 22c Swirl wall 23 Bush 23a Eccentric hole 24 Radial bearing 32 Balance weight

Claims (4)

A movement of at least the radial direction with respect to the housing is restricted, a fixed scroll member having an end plate and a spiral wall standing from the end plate, and a fixed scroll member disposed opposite to the fixed scroll member, and standing from the end plate and the end plate. An orbiting scroll member having a spiral wall provided, a drive shaft for transmitting rotational power, an eccentric shaft provided at an end of the drive shaft and deviated from the axis of the drive shaft; A radial bearing internally fitted in a boss formed on the back surface of the orbiting scroll member, and an eccentric hole into which the eccentric shaft is inserted. The radial shaft is externally fitted to the eccentric shaft through the eccentric hole and the radial In a scroll compressor comprising a bush supported to be relatively rotatable on a bearing, and a balance weight provided at one end of the bush and integrated with the bush,
A scroll compressor characterized in that when the bush is inclined, the outer peripheral surface of the bush is brought into contact with the radial bearing only at the end portion side where the balance weight is provided. The clearance between the eccentric shaft and the inner peripheral surface of the eccentric hole provided in the bush is A, the fitting length between the eccentric shaft and the inner peripheral surface of the eccentric hole provided in the bush is B, and the radial When the clearance between the bearing and the outer peripheral surface of the bush is C, and the fitting length between the radial bearing and the outer peripheral surface of the bush is D,
A / B <C / D
The scroll compressor according to claim 1, wherein   An anti-rotation mechanism is provided on the radially outer side of the boss portion of the orbiting scroll member, and the balance weight projects in a direction away from the orbiting scroll member, thereby avoiding interference with the anti-rotation mechanism. The scroll type compressor according to claim 1 or 2, characterized by the above-mentioned.   The scroll compressor according to any one of claims 1 to 3, wherein the radial bearing is a needle bearing.

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