JP6587827B2 - Fluid machinery - Google Patents

Description

  The present invention relates to a fluid machine, and more particularly to a fluid machine suitable for use in a Rankine circuit of a heat utilization device.

  The fluid machine disclosed in Patent Literature 1 includes a fixed scroll and a movable scroll, two scroll units that respectively perform the inflow and out of the working fluid in accordance with the revolving swivel movement of the movable scroll with respect to the fixed scroll, and the revolving swirl of each movable scroll. Two rotation mechanisms for converting the movements into rotational movements, rotation shafts respectively connected to the bosses respectively protruding from the back surfaces of the movable scroll substrates facing the two scroll units via the respective rotation mechanisms, A rotor disposed between the two scroll units and having a rotating shaft press-fitted, and an electric unit having a stator surrounding the rotor are provided.

Japanese Patent No. 4402199

  The fluid machine is a so-called twin scroll fluid machine, and the rotating shaft connected to the two scroll units is likely to be decentered and declinated. The eccentricity and declination of the rotating shaft can cause damage to the connecting part of the rotating shaft and sliding members (radial bearings, etc.) in the vicinity of the connecting part or lock during operation of the fluid machine, and excessive frictional force on the sliding member. And a large mechanical loss may occur in the operation of the fluid machine. On the other hand, in order to eliminate the eccentricity and declination of the rotating shaft, assembly errors and dimensional errors of the fluid machine must be strictly managed, resulting in a decrease in productivity of the fluid machine. In general, a means for eliminating the eccentricity and declination of the rotating shaft using a shaft coupling such as Oldham coupling is also conceivable. However, due to the presence of the shaft coupling, the fluid machine becomes longer in the axial direction, which may hinder downsizing.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a fluid machine that can improve both reliability and productivity while achieving downsizing. .

In order to achieve the above object, a fluid machine according to the present invention includes two scroll units each having a fixed and a movable scroll, and each of the movable fluids flowing in and out in accordance with a revolving orbiting motion of the movable scroll with respect to the fixed scroll, and each movable scroll. Two revolving mechanisms for reciprocating the revolving revolving motion and the revolving motion, and the bosses respectively projecting from the back surfaces of the movable scroll substrates facing each other of the two scroll units are connected to each other via the revolving mechanisms. A rotating shaft that generates a rotating motion, a rotor that is disposed between the two scroll units, and into which the rotating shaft is press-fitted, and an electric unit that has a stator that surrounds the rotor, the rotating shaft is connected to one of the turning mechanisms. A large-diameter shaft portion having a crank pin, a medium-diameter shaft portion press-fitted into the rotor and having a smaller diameter than the large-diameter shaft portion, and the other turning mechanism It is connected, than the medium diameter shaft portion possess a small diameter shaft portion of the small-diameter, each pivoting mechanism, preventing the rotation of movable scroll each orbital during exercise.

  According to the present invention, both reliability and productivity can be improved while downsizing a fluid machine.

It is a longitudinal section of a fluid machine concerning one embodiment of the present invention. It is a disassembled perspective view which shows the spline shaft coupling of FIG. It is a perspective view which expands and shows the external tooth of the spline shaft of FIG. It is the figure which showed the sliding state with the tooth | gear tip of the external tooth of FIG. 3, and the tooth bottom of an internal tooth. It is the figure which showed the sliding state with the tooth surface of the external tooth of FIG. 3, and the tooth surface of an internal tooth.

Hereinafter, a fluid machine 1 according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a fluid machine 1 is used as, for example, a Rankine circuit of a vehicle waste heat utilization device (not shown), and is used as a small power generation device for recovering heat of exhaust gas discharged from a vehicle engine and generating electric power. Used. The fluid machine 1 includes two expansion units (scroll units) 2A and 2B, and a power generation unit (electric unit) 4 disposed between the expansion units 2A and 2B.

  The refrigerant as the working fluid that has been brought into a low-temperature liquid state by the Rankine circuit receives the heat of the exhaust gas generated by the engine. As a result, the refrigerant is heated to a high-temperature and high-pressure superheated steam state. The expansion units 2A and 2B expand the refrigerant in the superheated steam state, and convert the thermal energy of the refrigerant into torque (rotational force) and output it. Torque output from the expansion units 2A, 2B is transmitted to the power generation unit 4.

  The power generation unit 4 is appropriately connected to an electrical load such as a battery that uses or stores the generated power. Thus, the heat energy of the refrigerant generated by the heat of the exhaust gas of the engine is converted into torque output from the expansion units 2A and 2B, and further converted into electric energy by the power generation unit 4 and used outside the fluid machine 1. Is done.

  The expansion units 2A and 2B are scroll type expanders each having a swivel mechanism 6a and 6b as a mechanism part. In the case of this embodiment, the expansion units 2A and 2B have the same diameter and a spiral winding direction. Scrolls are used in opposite directions. The expansion unit 2A has a fixed scroll 8a and a movable scroll 10a arranged to mesh with the fixed scroll 8a. On the other hand, the expansion unit 2B has a fixed scroll 8b that is in a reverse rotation direction when the expansion unit 2A is in a normal rotation direction, and a movable scroll 10b that is arranged to mesh with the fixed scroll 8b. .

  Refrigerant expansion chambers 12a and 12b are formed between the fixed scroll 8a and the movable scroll 10a, and between the fixed scroll 8b and the movable scroll 10b, respectively. Refrigerant inlet ports 14a and 14b are opened on the back surfaces 8a2 and 8b2 of the substrates 8a1 and 8b1 of the fixed scrolls 8a and 8b, respectively. Refrigerant flowing into the expansion units 2A and 2B from the Rankine circuit through the inlet ports 14a and 14b revolves around the movable scrolls 10a and 10b with respect to the fixed scrolls 8a and 8b as the refrigerant expands in the expansion chambers 12a and 12b. Then, the gas flows out from the expansion units 2A and 2B through an outlet port (not shown) and is returned to the Rankine circuit.

  The back surfaces 10a2, 10b2 of the substrates 10a1, 10b1 of the movable scrolls 10a, 10b are positioned to face each other, and bosses 16a, 16b protrude from the back surfaces 10a2, 10b2, respectively. Rotating shafts 18 are connected to the bosses 16a and 16b positioned to face each other in the fluid machine 1 via the turning mechanisms 6a and 6b, respectively. As will be described in detail later, each of the turning mechanisms 6a and 6b forms a mechanism for converting the revolving turning motion of each of the movable scrolls 10a and 10b into the rotation motion of the rotary shaft 18, respectively.

  The power generation unit 4 includes a rotor 20 into which the rotary shaft 18 is press-fitted and a stator 22 that surrounds the rotor 20. The rotor 20 is formed of, for example, a permanent magnet and is rotated together with the rotating shaft 18. The stator 22 has a yoke 22a fitted in the casing 24 of the power generation unit 4 and a plurality of sets of coils 22b wound around the yoke 22a. The coil 22b is wired so as to generate a three-phase alternating current as the rotor 20 rotates, and the generated alternating current is externally loaded from the hermetic terminal 26 protruding from the casing 24 of the power generation unit 4 through the lead wire. To be supplied.

  Here, the rotary shaft 18 of the present embodiment is formed of a large diameter shaft portion 28, a medium diameter shaft portion 30, and a small diameter shaft portion 32. The large-diameter shaft portion 28 has a crank pin 28a at the tip, and is connected to one turning mechanism 6a by the crank pin 28a. The medium-diameter shaft portion 30 is formed with a smaller diameter than the large-diameter shaft portion 28 via a constricted portion 30 a between the medium-diameter shaft portion 28 and is press-fitted into the rotor 20 of the power generation unit 4. The small-diameter shaft portion 32 is formed with a smaller diameter than the medium-diameter shaft portion 30 via the taper portion 30b, and is connected to the other turning mechanism 6b.

  One turning mechanism 6a has an eccentric bush 36a rotatably disposed in the boss 16a via a needle bearing 34a, and a crank pin 28a is inserted into the eccentric bush 36a. The other turning mechanism 6b has an eccentric bush 36b that is rotatably disposed in the boss 16b via a needle bearing 34b, and a crankpin bush 40 that forms a connecting portion 38 with the small-diameter shaft portion 32. .

  The crankpin bushing 40 includes a crankpin portion 40a that is inserted into the eccentric bushing 36b, and a bushing portion 40b that is integrated with the crankpin portion 40a. The connecting portion 38 is formed in the bush portion 40b. As the refrigerant expands in the respective expansion chambers 12a and 12b, the movable scrolls 10a and 10b are revolved with respect to the fixed scrolls 8a and 8b, respectively. The revolving revolving motion is rotated by the revolving mechanisms 6a and 6b. It is converted into a rotational motion of the shaft 18.

  The fluid machine 1 also includes a pair of radial bearings 42a and 42b that rotatably support the large-diameter shaft portion 28 and the small-diameter shaft portion 32 of the rotary shaft 18, respectively. These radial bearings 42a and 42b are fixed to a partition wall (end portion) 46a1 of a casing 46a and a partition wall 24a of the casing 24, respectively, which will be described later. In the case of the present embodiment, the radial bearings 42a and 42b are the same and have the same inner diameter.

  Each of the turning mechanisms 6a and 6b has ball couplings 44a and 44b that prevent the rotation of the movable scrolls 10a and 10b during the revolving turning motion and receive a thrust load. The ball coupling 44a is disposed between the back surface 10a2 of the movable scroll 10a and the partition wall 46a1 of the casing 46a facing the back surface 10a2. A radial bearing 42a is press-fitted and fixed inside the partition wall 46a1. On the other hand, the ball coupling 44b is disposed between the back surface 10b2 of the movable scroll 10b and the partition wall 24a of the casing 24 facing the back surface 10b2.

  The expansion units 2A and 2B include casings (scroll unit casings) 46a and 46b, respectively, in which the movable scrolls 10a and 10b are accommodated so as to be capable of revolving. The casing 46a is formed in a cup shape having a partition wall 46a1 and an open end 46a2. An outer peripheral portion 8a3 of the fixed scroll 8a is fitted in the opening end 46a2 in the radial direction of the rotary shaft 18, and an O-ring (first elastic member) 48a is interposed between the opening end 46a2 and the outer peripheral portion 8a3. A seal portion (first seal portion) 50a is formed.

  On the other hand, the casing 46b is formed in a cylindrical shape, and the outer peripheral portion 8b3 of the fixed scroll 8b is fitted in one opening end 46b1 in the radial direction of the rotary shaft 18, and between the opening end 46b1 and the outer peripheral portion 8b3. A seal portion (first seal portion) 50b is formed through an O-ring (first elastic member) 48b.

  The seal portions 50a and 50b form seal surfaces 50a1 and 50b1 along the axis of the rotary shaft 18 on the outer peripheral portions 8a3 and 8b3, respectively. The O-rings 48a and 48b are mounted in annular seal grooves 50a2 and 50b2 that are recessed in the seal surfaces 50a1 and 50b1, respectively. Along with the formation of the seal portions 50a and 50b, the O-rings 48a and 48b rotate the inner peripheral surfaces 46a3 and 46b3 of the casings 46a and 46b from the outer peripheral portions 8a3 and 8b3 side of the fixed scrolls 8a and 8b by the elastic force. Each is pressed toward the radial direction of 18.

  The power generation unit 4 includes a casing (electric unit casing) 24 in which a stator 22 is fitted. The casing 24 is formed in a cup shape having a partition wall 24a and an open end 24b. An outer peripheral surface 46a4 of the partition wall 46a1 of the casing 46a of the expansion unit 2A is fitted in the opening end 24b in the radial direction of the rotary shaft 18, and an O-ring (second ring) is provided between the opening end 24b and the outer peripheral surface 46a4. A seal part (second seal part) 50c is formed via an elastic member 48c. A radial bearing 42b is press-fitted and fixed inside the partition wall 24a.

  On the other hand, on the outer peripheral surface 24a1 forming the small diameter end of the partition wall 24a of the casing 24 of the power generation unit 4, the other open end (end portion) 46b2 of the cylindrical casing 46b of the expansion unit 2B is in the radial direction of the rotary shaft 18. A seal portion (second seal portion) 50d is formed between the opening end 46b2 and the outer peripheral surface 24a1 via an O-ring (second elastic member) 48d.

  The seal portions 50c and 50d form seal surfaces 50c1 and 50d1 along the axis of the rotary shaft 18 on the outer peripheral surfaces 46a4 and 24a1, respectively. The O-rings 48c and 48d are mounted in annular seal grooves 50c2 and 50d2 that are recessed in the seal surfaces 50c1 and 50d1, respectively. With the formation of the seal portions 50c and 50d, the O-rings 48c and 48d cause the inner peripheral surfaces 24c and 46b3 of the casings 24 and 46b to face the radial direction of the rotary shaft 18 from the outer peripheral surfaces 46a4 and 24a1 side by these elastic forces. Press each.

Hereinafter, the outline of the assembly procedure of the rotating shaft 18 in the fluid machine 1 will be described. First, the crank pin 28a is inserted into the eccentric bush 36a while the large-diameter shaft portion 28 is press-fitted inside the radial bearing 42a.
Next, the inside of the casing 24 in which the stator 22 is assembled is prepared. Further, the rotary shaft 18 is inserted into the rotor 20 from the small diameter shaft portion 32 side, and the medium diameter shaft portion 30 is press-fitted into the rotor 20.

On the other hand, the bush portion 40b of the crankpin bush 40 is press-fitted into the casing 24 inside the radial bearing 42b. Finally, the casing 46b is connected to the casing 24 by fitting the casing 46b and the casing 24 while connecting the small diameter shaft portion 32 to the bush portion 40b.
Thus, the assembly of the rotary shaft 18 and the connection of the substrates 8a1 and 8b1 of the fixed scrolls 8a and 8b, the casings 46a and 46b of the expansion units 2A and 2B, and the casing 24 of the power generation unit 4 are completed at the same timing. A sealed housing of the machine 1 is formed.

Here, as shown in FIG. 2, the small diameter shaft portion 32 is a spline shaft, and outer teeth 52 are formed on the outer peripheral surface 32 a of the small diameter shaft portion 32.
On the other hand, the bush portion 40b of the crankpin bush 40 has a bottomed cylindrical shape, and an inner tooth 54 with which the outer teeth 52 are engaged by inserting the small diameter shaft portion 32 is formed on the inner peripheral surface 40b1. Yes. That is, the connecting portion 38 between the small-diameter shaft portion 32 and the bush portion 40b includes an external tooth 52 provided on the outer peripheral surface 32a of the small-diameter shaft portion 32 and an internal tooth 54 provided on the inner peripheral surface 40b1 of the bush portion 40b. The spline shaft coupling 56 is formed. In the spline shaft coupling 56, the shape and size of a part of the opposing external teeth 52 and internal teeth 54 may be changed complementarily to serve as positioning means for the small diameter shaft portion 32 and the bush portion 40b.

As shown in FIG. 3, the external teeth 52 are formed by applying crowning to the teeth forming the involute spline. The inner teeth 54 are formed as parallel teeth forming an involute spline.
Specifically, as shown in FIG. 4, a convex crowning process is applied to the tooth tip 52 a of the external tooth 52.

  On the other hand, as shown in FIG. 5, convex crowning is also applied to the tooth surface 52 b of the external tooth 52. Thus, the rotation shaft 18 is allowed to deviate from the rotation shaft 18 at the connecting portion 38.

  As described above, in the fluid machine 1 of the present embodiment, the rotary shaft 18 is formed of the large diameter shaft portion 28, the medium diameter shaft portion 30, and the small diameter shaft portion 32, whereby the large diameter shaft portion 28 with respect to the radial bearing 42a. The press fitting, the press fitting of the medium diameter shaft portion 30 to the rotor 20, the press fitting of the bush portion 40b of the crank pin bush 40 to the radial bearing 42b, and the formation of the connecting portion 38 are sequentially performed at the same timing as the connection of the casings 24, 46a, 46b. Can do. Therefore, it is possible to improve the assembling property of the rotating shaft 18 and the housing in the fluid machine 1 and to improve the productivity of the fluid machine 1.

Further, the bush portion 40b is press-fitted inside the radial bearing 42b, whereby the axial length of the rotary shaft 18 is prevented from being increased with the formation of the connecting portion 38, and the size reduction of the fluid machine 1 is promoted. Can do.
Further, in each casing 24, 46 a, 46 b, the seal portions 50 a to 50 d that are fitted in the radial direction of the rotary shaft 18 are formed, so that the center of the inner diameter of each casing 24, 46 a, 46 b is the axis of the rotary shaft 18. To be aligned. Therefore, the assembly accuracy of the fluid machine 1 can be improved.

Further, the O-rings 48a to 48d absorb the eccentricity generated between the casings 24, 46a, 46b and the rotary shaft 18 due to the assembly error of the fluid machine 1 and the dimensional errors of the components of the fluid machine 1. can do. Therefore, it is not necessary to strictly manage assembly errors and dimensional errors of the fluid machine 1, so that the productivity of the fluid machine 1 can be improved.
Further, the connecting portion 38 is formed by the spline shaft coupling 56, and convex crowning is applied to both the tooth tip 52a and the tooth surface 52b of the external tooth 52, so that the deflection angle of the rotating shaft 18 at the connecting portion 38 is reduced. Permissible.

  Here, it is assumed that a spline shaft coupling in which the outer teeth 52 and the inner teeth 54 are both parallel teeth is used for the connecting portion 38. In this case, due to the assembly error of the fluid machine 1 and the dimensional error of the components of the fluid machine 1, the rotary shaft 18 is assembled with an inclination with respect to the radial center of the fluid machine 1, and 52 inclines and slides, and a twisting force acts on the radial bearing 42b.

  When the force in the twisting direction acts on the radial bearing 42b, the radial bearing 42b is damaged or locked. As a result, an excessive frictional force is generated in the connecting portion 38 and the radial bearing 42b. Large machine losses can occur.

  On the other hand, in the present embodiment, both the radial and circumferential declination of the rotating shaft 18 due to the assembly error and dimensional error of the fluid machine 1 in the connecting portion 38 are allowed, so that the connecting portion 38 Since it is not necessary to strictly manage the assembly error and dimensional error of the fluid machine 1 that influence, both the reliability and productivity of the fluid machine 1 can be improved.

Although the description of the embodiment of the present invention has been completed above, the present invention is not limited to this form, and various modifications can be made without departing from the spirit of the present invention.
For example, the connecting portion 38 may be formed by a gear coupling other than the spline shaft coupling 56 or a coupling by a key groove. Even in this case, the productivity of the fluid machine 1 is improved at least as compared with the prior art by improving the assembling property of the rotating shaft 18 in the fluid machine 1 and absorbing the eccentricity generated with the rotating shaft 18. can do.

  Further, the scroll diameters of the expansion units 2A and 2B may not be the same, and the radial bearings 42a and 42b may not be the same. However, by making the expansion units 2A and 2B and the radial bearings 42a and 42b the same type having a small diameter, the diameter of the fluid machine 1 as a whole can be reduced, and the possibility of diverting existing component parts is also increased. Thereby, it is possible to realize the fluid machine 1 capable of taking in a large amount of refrigerant while reducing the manufacturing cost of the fluid machine 1 and thus improving the productivity of the fluid machine 1.

Further, one or both of the expansion units 2A and 2B can be used as a compression unit, and a motor unit that drives the compression unit may be used instead of the power generation unit 4, or a power generation unit You may use the electric power generation drive unit which added the motor drive function to 4. FIG.
Moreover, the fluid machine 1 of this embodiment is applicable not only to the waste heat utilization apparatus for vehicles but to the Rankine circuit of various heat utilization apparatuses.

1 Fluid machinery 2A, 2B Expansion unit (scroll unit)
4 Power generation unit (electric unit)
6a Turning mechanism (one turning mechanism)
6b Turning mechanism (the other turning mechanism)
8a, 8b Fixed scroll 8a3, 8b3 Outer peripheral part 10a, 10b Movable scroll 10a1, 10b1 Substrate 10a2, 10b2 Back 16a, 16b Boss 18 Rotating shaft 20 Rotor 22 Stator 24 Casing (Case for electric unit)
28 Large-diameter shaft portion 28a Crank pin 30 Medium-diameter shaft portion 32 Small-diameter shaft portion 32a Outer peripheral surface of small-diameter shaft portion 36b Eccentric bush 38 Connection portion 40 Crank pin bush 40a Crank pin portion 40b Bush portion 40b1 Inner peripheral surface 42a of bush portion, 42b Radial bearing 46a, 46b Casing (scroll unit casing)
46a1 Partition wall (end)
46b2 Open end (end)
48a, 48b O-ring (first elastic member)
48c, 48d O-ring (second elastic member)
50a, 50b Seal part (first seal part)
50c, 50d Seal part (second seal part)
52 External teeth 52a Tooth tips 52b Tooth surface 54 Internal teeth 56 Spline shaft coupling

Claims (7)

Two scroll units each having a fixed and a movable scroll, and each of the working fluid flowing in and out in accordance with a revolving orbiting motion of the movable scroll with respect to the fixed scroll;
Two revolving mechanisms for mutually converting the revolving revolving motion and the rotational motion of each of the movable scrolls;
Rotating shafts that are coupled to the bosses respectively projecting from the back surfaces of the movable scroll substrates facing each other of the two scroll units via the turning mechanisms, respectively, and generate the rotational motion;
A rotor disposed between the two scroll units, the rotary shaft being press-fitted, and an electric unit having a stator surrounding the rotor;
The rotation axis is
A large-diameter shaft portion having a crankpin connected to the one turning mechanism;
A medium diameter shaft portion having a smaller diameter than the large diameter shaft portion, and press-fitted into the rotor;
Coupled to said other turning mechanism, possess a small diameter shaft portion of smaller diameter than the in-diameter shaft portion,
Each said turning mechanism is a fluid machine which prevents rotation of each said movable scroll during each revolution turning motion . The other turning mechanism is
An eccentric bushing rotatably disposed within the boss;
A crankpin bushing having a crankpin portion inserted through the eccentric bushing and a bushing portion forming a connecting portion with the small diameter shaft portion;
The fluid machine includes a pair of radial bearings that rotatably support the large-diameter shaft portion and the small-diameter shaft portion of the rotating shaft,
The fluid machine according to claim 1, wherein the bush portion is press-fitted inside a radial bearing on the small-diameter shaft portion side.   The two scroll units are fitted to the outer peripheral portion of the fixed scroll in the radial direction of the rotating shaft, and a first seal portion is formed between each of the outer peripheral portions via an annular first elastic member. The fluid machine according to claim 2, comprising two scroll unit casings.   Arranged between the scroll casings, fitted into the respective end portions of the scroll casings in the radial direction of the rotary shaft, and annular second elastic members between the end portions, respectively. The fluid machine according to claim 3, comprising a casing for an electric unit that forms two second seal portions. The bush portion has a bottomed cylindrical shape,
The said connection part is formed by the coupling by the gear which engages the outer peripheral surface of the said small diameter shaft part, and the inner peripheral surface of the said bush part, or a keyway. Fluid machinery.   The connecting portion is formed by a spline shaft joint including external teeth provided on the outer peripheral surface of the small-diameter shaft portion and internal teeth provided on the inner peripheral surface of the bush portion and meshed with the external teeth. The fluid machine according to claim 5.   The fluid machine according to claim 6, wherein the external teeth are subjected to convex crowning on both the tooth tips and the tooth surfaces.

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