JP5818554B2 - Electric compressor - Google Patents

Description

  The present invention relates to an electric compressor used for, for example, a vehicle air conditioner, and more particularly to a compressor having an improved main shaft for transmitting power of an electric motor to a compression mechanism.

  For example, a scroll-type electric compressor 100 disclosed in Patent Document 1 includes a housing 103, a fixed scroll 105 and a orbiting scroll 107 that compress refrigerant, and a main shaft that drives the orbiting scroll 107, as shown in FIG. 109, a drive bush part 111, and an inverter motor 113. The rotational driving force of the inverter motor 113 is transmitted to the orbiting scroll 107 via the main shaft 9 and the drive bush portion 111.

  As shown in FIG. 7A, the main shaft 109 includes a columnar crankshaft 115 fixed to the inverter motor 113, a disk-shaped fitting portion 117 having a larger radius than the crankshaft 115, and a crankshaft. 115 and a crankpin 119 that is eccentric from the central axis 115 and extends along the central axis.

Since the fitting portion 117 is a portion that is fitted and supported by the radial bearing 123 by being press-fitted, the outer periphery thereof needs to be processed with high accuracy. Further, the crank pin 119 needs to be fitted with the drive bush portion 111, and it is also necessary to be processed with high accuracy in order to reduce wear.
Such machining of the main shaft 109 is performed using a lathe. However, since both the fitting portion 117 and the crank pin 119 need to have high-precision finished surfaces, they are fitted when machining the outer periphery of the crankshaft 115. It should be avoided to chuck the joint portion 117 and the crank pin 119 directly. Therefore, as shown in FIG. 7B, the chucking jig J attached to the fitting portion 117 and the crankpin 119 is gripped by the chucking device, and the tip of the crankshaft 115 is supported by the center S. Process it.

JP 2008-208717 A

However, the work of attaching the chucking jig J becomes a factor that increases the manufacturing cost. In addition, when the chucking jig J is used, the machining accuracy tends to be inferior to machining by directly chucking the spindle 109.
The present invention has been made based on such a problem, and a spindle capable of machining the outer periphery of a crankshaft without leaving a chucking mark on a fitting portion or a crankpin without using a chucking jig. An object is to provide an electric compressor provided.

An electric compressor of the present invention includes a compression mechanism that compresses a refrigerant, an electric motor that generates a rotational force that drives the compression mechanism, a main shaft that transmits the rotational force generated by the electric motor to the compression mechanism, and a main shaft. And a bearing to support.
The main shaft according to the present invention includes a fitting portion, a crankshaft, and a crankpin.
When the fitting portion is fitted into the bearing, the main shaft is rotatably supported by the bearing.
The crankshaft is provided on one surface side in the axial direction of the fitting portion. Also. The crankshaft is fixed to the electric motor.
The crank pin is provided on the other surface side in the axial direction of the fitting portion. Also. The crankpin outputs a rotational force toward the compression mechanism.
The main shaft also includes a chucking portion. The chucking portion is provided between the fitting portion or between the fitting portion and the crank pin. The chucking portion has an arc surface having a smaller radius of curvature than the fitting portion on the outer periphery.

The chucking part according to the present invention includes at least two forms.
The 1st form is provided between a fitting part and a crankpin. This chucking portion has a disk-like outer shape. The outer periphery of this chucking portion is entirely made of a circular arc surface.
The 2nd form is provided in a fitting part. This chucking part is comprised by the circular arc surface which recedes toward the center axis | shaft of a fitting part rather than the outer periphery of a fitting part. And this chucking part is provided in the several places of the outer peripheral direction of a fitting part, Preferably it is provided in three or more places.

  In the electric compressor of the present invention, it is preferable that the chucking portion is disposed inside the bearing. Since the gap formed between the chucking portion and the bearing functions as an oil reservoir that holds the lubricating oil, it is possible to prevent the surroundings from being deficient in the lubricating oil.

  According to the present invention, the chucking portion having an arc surface having a smaller radius of curvature than the fitting portion is provided between the fitting portion of the main shaft or the fitting portion and the crank pin. The chucking portion can be gripped by the chucking device of the machine tool without attaching a jig. Therefore, the spindle can be machined with high accuracy. Moreover, since the chucking portion is fitted to another member of the electric compressor, for example, it does not need to be a finished surface, and a chucking mark may remain.

It is sectional drawing which shows schematic structure of the electric scroll type compressor in this Embodiment. The main axis in this Embodiment is shown, (a) is a side view, (b) is a top view. It is the elements on larger scale of the electric scroll type compressor in this Embodiment. It is a figure which shows the positional relationship of the main axis | shaft in this Embodiment, and the bearing which supports a main axis | shaft. It is a top view which shows the modification of the main axis | shaft in this Embodiment. It is sectional drawing which shows schematic structure of the conventional electric scroll compressor. A conventional spindle is shown, (a) shows a spindle alone, and (b) shows a situation where it is supported by a lathe for cutting.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
In this embodiment, an example applied to a horizontal type scroll type electric compressor driven by an inverter motor will be described.
[Scroll compressor main elements]
As shown in FIG. 1, the electric compressor 1 includes a housing 3, a fixed scroll 5 and a orbiting scroll 7 (compression mechanism) that compress refrigerant used in a vehicle air conditioner, and a main shaft 9 that drives the orbiting scroll 7. The drive bush 11 and the inverter motor 13 are provided.

[housing]
The housing 3 is a housing that houses the fixed scroll 5, the orbiting scroll 7, the main shaft 9, the inverter motor 13, and the like. The housing 3 includes a first housing 15, a second housing 17, and a motor case 19.

  The first housing 15 is a member formed in a bottomed cylindrical shape, and the fixed scroll 5 is fixed to the bottom surface. A discharge chamber 21 into which the refrigerant compressed by the fixed scroll 5 and the orbiting scroll 7 flows is formed between the fixed scroll 5 and the first housing 15.

The second housing 17 is disposed so as to be sandwiched between the first housing 15 and the motor case 19.
A radial bearing 23 that rotatably supports the main shaft 9 is provided in the second housing 17, and a suction passage 25 that extends along the central axis of the main shaft 9 is provided in the second housing 17. .

As shown in FIG. 1, the motor case 19 is a member formed in a bottomed cylindrical shape, and a stator 63 of the inverter motor 13 is fixed therein. The motor case 19 is provided with a suction port (not shown) through which refrigerant flows from the outside and an inverter housing box 27.
The inverter accommodation box 27 is opened toward the outside in the radial direction of the motor case 19, and an inverter portion 65 that controls the drive of the inverter motor 13 is accommodated therein.

[scroll]
As shown in FIG. 1, the fixed scroll 5 and the orbiting scroll 7 form a closed compression chamber C to compress the refrigerant.
The fixed scroll 5 includes a fixed end plate 29 and a spiral fixed wrap 31 extending from the fixed end plate 29 toward the orbiting scroll 7.
A discharge hole 33 is provided in the center of the fixed end plate 29, and the refrigerant compressed in the compression chamber C is discharged to the discharge chamber 21 through the discharge hole 33.

The orbiting scroll 7 includes an orbiting end plate 35 and a spiral orbiting wrap 37 extending from the orbiting end plate 35 toward the fixed scroll 5. The orbiting scroll 7 is supported by the main shaft 9 and the rotation preventing portion 39 so as to be revolved.
The turning end plate 35 includes a cylindrical boss portion 41 extending toward the main shaft 9 on a surface facing the main shaft 9. The boss portion 41 is provided with a turning portion bearing 54 that rotatably supports the bush 53 to which the revolution driving force by the main shaft 9 is transmitted.

[Spindle]
As shown in FIG. 1, the main shaft 9 is a columnar member that extends from the inverter motor 13 toward the orbiting scroll 7. As shown in FIGS. 2 and 3, the main shaft 9 includes a columnar crankshaft 43 fixed to the rotor 61, a disc-shaped fitting portion 45 having a diameter larger than that of the crankshaft 43, and the crankshaft 43. And a crankpin 47 extending along the central axis from a position eccentric from the central axis.
The crankshaft 43 has a central axis arranged substantially horizontally and transmits a rotational driving force generated by the rotor 61 and the stator 63 to the orbiting scroll 7.
The fitting portion 45 is a portion that is fitted and supported by the radial bearing 23, and the crankshaft 43 is provided on one surface side in the axial direction, and the crankpin 47 is provided on the other surface side. The fitting portion 45 is provided with a limit hole 49 on the other surface side where the limit pin 55 (FIG. 3) is inserted. The fitting portion 45 is supported by the radial bearing 23 by being press-fitted into the inner ring 23i.
The crank pin 47 is a columnar member that transmits the rotational driving force transmitted to the crankshaft 43 to the orbiting scroll 7 and drives the orbiting scroll 7 to orbit. The crank pin 47 extends toward the orbiting scroll 7 along the central axis of the crankshaft 43 from a position eccentric from the center of the fitting portion 45.

The limit hole 49 adjusts the revolution radius of the orbiting scroll 7 together with the limit pin 55.
The limit hole 49 is a hole extending toward the crankshaft 43 along the central axis of the crankshaft 43 from another eccentric position different from the crankshaft 43 in the fitting portion 45. The diameter of the limit hole 49 is formed larger than the diameter of the limit pin.

The main shaft 9 includes a chucking portion 51 between the fitting portion 45 and the crank pin 47. The chucking portion 51 is a disk-shaped member that is formed coaxially with the fitting portion 45 and has a smaller diameter than the fitting portion 45. The disk-shaped chucking portion 51 can be easily processed and formed by a lathe. The crank pin 47 and the limit hole 49 are provided in the plane area of the chucking portion 51.
When machining the outer periphery of the crankshaft 43, the chucking device holds the chucking portion 51 at one end of the main shaft 9, and the other end supports the front end surface of the crankshaft 43 by a so-called center. Since the chucking portion 51 is not fitted with another member after being assembled to the electric compressor 1, it is possible that a chucking mark remains on the outer periphery.
The main shaft 9 is supported at one end (chucking portion 51) by a chucking device and at the other end by a center S (FIG. 7B).

A chucking device mainly used for a lathe is a scroll chuck. This chucking device incorporates a cam having a spiral (scroll) -like groove, and a plurality of claws for gripping a workpiece can be opened and closed simultaneously by rotating only one handle. A scroll chuck having three claws is the mainstream. An independent chuck in which each of the claws individually operates is also used for the lathe. Many of these chucking devices have four claws.
The chucking portion 51 is held along the tangent line by the claw because the gripped outer periphery forms an arc surface even in any chucking device having any number of claws of 2 to 4. Therefore, since the main shaft 9 including the chucking portion 51 is securely gripped by the gripping claws, it is difficult to cause positional displacement during processing and can be processed with high accuracy. In addition, since the main shaft 9 can be gripped without using a jig, the cost reduction effect due to the reduction in man-hours is remarkable. In addition, the other effect by providing the chucking part 51 is mentioned later.

[Drive bush]
A drive bushing 11 is provided between the main shaft 9 and the orbiting scroll 7 as shown in FIGS.
As shown in FIG. 4, the drive bush portion 11 includes a bush 53, a limit pin 55, and a counterweight 57.
The bush 53 is a substantially cylindrical member that is disposed between the crankpin 47 and the boss portion 41 and transmits the revolving driving force to the orbiting scroll 7. A crank hole 59 into which the crank pin 47 is inserted is formed at a position eccentric from the center of the bush 53.
The limit pin 55 is a cylindrical member that is disposed between the bush 53 and the fitting portion 45 and adjusts the revolution radius of the orbiting scroll 7 together with the limit hole 49. The limit pin 55 extends toward the fitting portion 45 along the central axis of the main shaft 9 from another eccentric position in the bush 53 different from the crank pin 47.

  The counterweight 57 is a member that adjusts the pressing force of the orbiting scroll 7 against the fixed scroll 5 and balances it. The counterweight 57 is a bowl-shaped member extending in a semicircular shape from the circumferential surface on the main shaft 9 side in the bush 53 toward the radially outer side.

[motor]
The inverter motor 13 is a motor that is rotationally driven by a frequency-controlled alternating current, and is an electric part that drives the orbiting scroll 7 to revolve.
As shown in FIG. 1, the inverter motor 13 includes a rotor 61 and a stator 63 for revolving the orbiting scroll 7 via the main shaft 9 and the drive bush portion 11, and an inverter unit 65 for controlling an alternating current supplied to the stator 63. And are provided.

The rotor 61 generates a rotational driving force by an alternating magnetic field formed by the stator 63, and includes a permanent magnet formed in a cylindrical shape. A crankshaft 43 of the main shaft 9 is fixed to the rotor 61.
The stator 63 rotates the rotor 61 by forming an alternating magnetic field based on the alternating current supplied from the inverter unit 65. The stator 63 is fixed to the inner peripheral surface of the motor case 19 by a method such as shrink fitting.

  The inverter unit 65 controls an alternating current supplied to the stator 63 and is arranged in the inverter housing box 27. The inverter unit 65 includes a capacitor 67, a plurality of substrates 71 including electronic elements such as a power transistor 69, and a terminal 73.

[Compressor operation]
Next, the procedure in which the electric compressor 1 having the above-described configuration compresses the refrigerant will be described.
The frequency of the direct current supplied from the outside of the inverter is controlled by an electronic element such as the power transistor 69 of the inverter unit 65 and supplied to the stator 63.
The stator 63 forms an alternating magnetic field based on the alternating current whose frequency is controlled, and the rotor 61 generates a rotational driving force by interaction with the formed alternating magnetic field. The rotational driving force generated by the rotor 61 is transmitted to the main shaft 9.

  The rotational driving force is transmitted to the crankshaft 43 and the fitting portion 45 of the main shaft 9, and the crankpin 47 is driven to rotate by the rotation of the fitting portion 45. The orbiting motion of the crankpin 47 is transmitted to the orbiting scroll 7 through the bush 53 and the boss portion 41. The orbiting scroll 7 is driven to revolve while its rotation motion is restricted by the rotation prevention unit 39.

When the orbiting scroll 7 is driven to revolve, the compression chamber C formed between the fixed scroll 5 takes in the refrigerant flowing into the electric compressor 1 from the motor case 19 and compresses it. Specifically, the compression chamber C takes in the refrigerant at the outer peripheral ends of the fixed scroll 5 and the orbiting scroll 7. Then, due to the revolution of the orbiting scroll 7, the compression chamber C decreases in volume as it moves from the outer peripheral end toward the center along the fixed lap 31 and the orbiting wrap 37, and compresses the taken-in refrigerant.
The refrigerant compressed in the compression chamber C is discharged to the discharge chamber 21 through the discharge hole 33 of the fixed scroll 5 and is discharged from the discharge chamber 21 to the outside of the housing 3 (first housing 15).

[effect]
The main shaft 9 of the electric compressor 1 includes a chucking portion 51, and the outer periphery of the crankshaft 43 can be processed while the chucking portion 51 is directly gripped by the chucking device. Therefore, it is possible to save the labor of mounting the jig as in the conventional case, which contributes to the reduction of the manufacturing cost of the main shaft 9 and consequently the electric compressor 1.

Moreover, the electric compressor 1 in which the main shaft 9 including the chucking portion 51 is assembled also has the following effects.
The fitting portion 45 (or the periphery of the radial bearing 23) of the main shaft 9 has a required amount of lubricating oil constantly flowing between the metal members, for example, between the crankpin 47 and the drive bushing portion 11, for example. It is desired to be secured. In the present embodiment, the chucking portion 51 has a smaller diameter than the fitting portion 45. In addition, when the fitting portion 45 of the main shaft 9 is supported by the radial bearing 23, the chucking portion 51 is disposed inside the inner ring 23 i of the radial bearing 23. At this time, the thickness of the fitting portion 45 and the thickness of the chucking portion 51 is smaller than the thickness of the radial bearing 23. Therefore, a ring-shaped gap G (FIG. 3) is provided between the chucking portion 51 and the inner ring 23i so as to surround the periphery of the chucking portion 51. The lubricating oil supplied to the periphery of the radial bearing 23 enters and stays in the gap G. The gap G functions as a reservoir for lubricating oil and can supply a necessary amount of lubricating oil to the surroundings.

  Next, the chucking portion 51 prevents the stress generated in the fitting portion 45 from acting on the crank pin 47 by press-fitting the fitting portion 45 into the radial bearing 23 (inner ring 23i). That is, in the case of the conventional main shaft 109 shown in FIGS. 6 and 7, when the fitting portion 117 is press-fitted into the radial bearing 23, stress is generated in the fitting portion 117, and the fitting portion 117 may be deformed. Then, a displacement corresponding to this deformation, that is, a positional deviation occurs in the crank pin 119 provided in the fitting portion 117. This misalignment makes it difficult to fit the crank pin 119 and the drive bushing 111. On the other hand, in the case of the present embodiment, the chucking portion 51 is not in contact with the radial bearing 23, and therefore is smaller than the fitting portion 45 even if stress occurs. In this embodiment, since the crank pin 47 is provided via the chucking portion 51, the crank pin 47 does not shift or can be minimized. The crank pin 119 and the drive bush part 111 can be reliably fitted.

[Examples of changes]
In the above-described embodiment, the example in which the chucking portion 51 is disposed inside the inner ring 23i of the radial bearing 23 has been shown. However, the present invention is not limited thereto, and as shown in FIG. Includes a configuration in which is disposed outside the radial bearing 23 (inner ring 23i). Further, the present invention includes a form in which a part of the chucking portion 51 is disposed inside the inner ring 23i of the radial bearing 23 and a part is disposed outside the radial bearing 23 (inner ring 23i).
When the chucking portion 51 is disposed inside the inner ring 23i of the radial bearing 23, if the thickness of the fitting portion 45 is too thin, the fitting portion 45 cannot sufficiently receive the load from the radial bearing 23. . Therefore, as shown in FIG. 4B, the thickness of the chucking portion 51 may be set so as to exceed the range where the load is received from the rolling element 23b of the radial bearing 23 (arrow in the figure). preferable. On the other hand, it is preferable that the chucking portion 51 has a thickness of 3 mm or more in order to appropriately chuck with the chucking device.

Moreover, in the above embodiment, the chucking part 51 is provided between the fitting part 45 and the crankpin 47, and the whole outer periphery is used as the circular arc surface, but the present invention is not limited to this. For example, as shown in FIG. 5, the chucking portion 46 is formed in a specific region on the outer periphery of the fitting portion 45 where the nail of the chucking device hits. The chucking portion 46 has an arc surface 46 c whose radius of curvature is smaller than the radius of the fitting portion 45. The arc surface 46 c is retracted from the outer periphery of the fitting portion 45 toward the central axis of the fitting portion 45. In this example, the chucking portions 46 are formed at three locations at equal intervals corresponding to the chucking device including three gripping claws, but the number of the chucking portions 46 is arbitrary. In the example of FIG. 5, the chucking portion 46 is provided in a predetermined range in the axial direction of the fitting portion 45, but may be provided so as to penetrate in the axial direction of the fitting portion 45.
In the main shaft 9 shown in FIG. 5, a chucking portion 46 provided on the outer periphery of the fitting portion 45 is held by a nail of the chucking device. Further, since no chucking marks are left on the fitting portion 45 except the chucking portion 46, the surface of the fitting portion 45 press-fitted into the radial bearing 23 can ensure high processing accuracy.
In this case, it is preferable that the position where the chucking portion 46 is provided is provided in the same region through a large number of processed spindles 9. Since the position at which the spindle 9 is gripped by the chucking device is substantially the same, the machining conditions of each spindle 9 can be made uniform. Therefore, it is possible to reduce variations in accuracy of the individual spindles 9 to be machined.
In addition to the above, as long as the gist of the present invention is not deviated, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.

DESCRIPTION OF SYMBOLS 1 Electric compressor 3 Housing 5 Fixed scroll 7 Orbiting scroll 9 Main shaft 11 Drive bush part 13 Inverter motor 23 Radial bearing 23b Rolling element 23i Inner ring 43 Crankshaft 45 Fitting part 46, 51 Chucking part 46c Arc surface 47 Crank pin 61 Rotor 63 Stator C Compression chamber G Air gap

Claims (3)

A compression mechanism for compressing the refrigerant;
An electric motor for generating a rotational force for driving the compression mechanism;
A main shaft that transmits the rotational force generated by the electric motor to the compression mechanism;
A bearing that rotatably supports the main shaft,
The main shaft is
A fitting portion to be fitted to the bearing;
A crankshaft provided on one surface side in the axial direction of the fitting portion and fixed to the electric motor;
A crank pin that is provided on the other surface side in the axial direction of the fitting portion and outputs the rotational force toward the compression mechanism;
A chucking portion provided between the fitting portion or the fitting portion and the crank pin, and having an arc surface having a smaller radius of curvature than the fitting portion on an outer periphery;
An electric compressor comprising: The chucking portion is
A disk-shaped member provided between the fitting portion and the crank pin,
The electric compressor according to claim 1. The bearing is a radial bearing;
The chucking portion is disposed inside an inner ring constituting a radial bearing.
The electric compressor according to claim 2.

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