Patent Grant
12338825
This application is based on PCT filing PCT/JP2022/024058, filed Jun. 16, 2022, which claims priority from Japanese Patent Application No. 2021-134809, filed Aug. 20, 2021, the entire contents of each are incorporated herein by reference.
The present disclosure relates to a bearing structure including a shaft provided with an oil feed hole and a slide bearing configured to support the shaft, a compressor, and a refrigeration cycle apparatus.
In general, a rotary machine such as a compressor includes a bearing structure including a shaft configured to rotate and a slide bearing configured to hold the shaft so that the shaft can rotate. The shaft is provided with an oil feed hole through which lubricating oil is supplied to sliding parts of the shaft and the slide bearing. There is a conventional compressor including a main oil feed hole provided inside a shaft and extending in an axial direction and a branch oil feed hole branching off from the main oil feed hole in a radial direction of the shaft (see, for example, Patent Literature 1). While the shaft is rotating, lubricating oil in the main feed oil hole is subjected to centrifugal force acting outward in the radial direction, whereby the lubricating oil flows from the main oil feed hole to the branch oil feed hole and is supplied to sliding parts of the shaft and a slide bearing. One possible factor that causes abrasion on the sliding parts is that foreign matter such as abrasion powder generated on the sliding parts is supplied together with the lubricating oil to the sliding parts via an oil feed structure of the shaft. The foreign matter supplied together with the lubricating oil to the sliding parts is carried in a direction of rotation of the shaft along with sliding movements of the shaft and the slide bearing while being sandwiched between an outer circumferential surface of the shaft and an inner circumferential surface of the slide bearing. At this point in time, the outer circumferential surface of the shaft and the inner circumferential surface of the slide bearing are scraped against by the foreign matter, whereby abrasion occurs on the sliding parts to generate abrasion powder to further increase the amount of foreign matter (including abrasion powder) inside the compressor. Accordingly, abrasion of the slide bearing and the shaft by the foreign matter is effectively reduced by separating the foreign matter from the lubricating oil.
In the compressor of Patent Literature 1, an oil feed groove communicating with the branch oil feed hole and extending in the axial direction is provided in a location on the outer circumferential surface of the crank shaft (shaft) where the branch oil feed hole is provided in a circumferential direction and that is furthest forward in the direction of rotation of the crank shaft. Further, in the compressor of Patent Literature 1, a drain groove not communicating with the branch oil feed hole but extending in the axial direction is provided in a location on the outer circumferential surface of the crank shaft that is further backward in the direction of rotation than the location where the oil feed groove is provided in the circumferential direction, and a sliding area is formed between the oil feed groove and the drain groove. The compressor of Patent Literature 1 is configured such that of the foreign matter supplied to the gap between the crank shaft and the slide bearing via the branch oil feed hole, foreign matter of a certain size (e.g. foreign matter that is larger than this gap) is either drained out of the bearing structure by being trapped in the oil feed groove immediately after leaving an oil feed port or drained out of the bearing structure by being trapped in the drain groove after leaving the oil feed port and passing through the sliding area.
However, in the compressor of Patent Literature 1, since foreign matter separating spaces such as the oil feed groove and the drain groove are provided further backward than, that is, downstream of, the oil feed port in the direction in which the lubricating oil flows, the amount of foreign matter that is supplied to the gap between the slide bearing and the crank shaft cannot be reduced. Further, in the compressor of Patent Literature 1, a portion of the foreign matter supplied to the gap between the slide bearing and the crank shaft that has a size about equal to or smaller than the gap (clearance) between the slide bearing and the crank shaft remains without being trapped in the oil feed groove or the drain groove and abrades the sliding parts. Accordingly, Patent Literature 1 cannot sufficiently bring about an effect of reducing abrasion on sliding parts of a rotor such as a shaft and a slide bearing.
The present disclosure was made to solve problems such as those noted above and has as an object to provide a bearing structure, a compressor, and a refrigeration cycle apparatus with an ever-further reduction in abrasion on sliding parts of a rotor and a slide bearing.
A bearing structure according to an embodiment of the present disclosure is a rotary machine including a rotor having a cylindrical shape and having a main oil feed hole through which lubricating oil passes and that is provided in an axial direction and a slide bearing provided outward in a radial direction with a gap between the rotor and the slide bearing and configured to hold the rotor so that the rotor rotates around an axis. The rotor is provided with a branch oil feed hole through which the gap and the main oil feed hole communicate with each other and through which the lubricating oil passes. A foreign matter separating portion configured to separate foreign matter from the lubricating oil is provided further backward in a direction of rotation of the rotor than the branch oil feed hole.
Further, a compressor according to an embodiment of the present disclosure includes the bearing structure and a closed vessel housing the bearing structure.
Further, a refrigeration cycle apparatus according to an embodiment of the present disclosure includes a refrigerant circuit in which the compressor, an evaporator, a pressure reducing device, and a condenser are connected via refrigerant pipes.
According to an embodiment of the present disclosure, a foreign matter separating portion configured to separate foreign matter from lubricating oil is provided further backward in the direction of rotation than the branch oil feed hole. Therefore, even in a case in which foreign matter is contained in lubricating oil flowing through the rotor, the action of inertial force on lubricating oil and foreign matter flowing through the branch oil feed hole is utilized so that foreign matter that is higher in density than the lubricating oil can be separated from the lubricating oil in the foreign matter separating portion. This inhibits foreign matter from being supplied from the branch oil feed hole of the rotor to the gap between the rotor and the slide bearing, thus making it possible to further reduce abrasion on sliding parts of the slide bearing and the shaft than has conventionally been the case.
As shown in
In Embodiment 1, the rotor is constituted by the shaft 3, and an outer circumferential portion 32 of the shaft 3 slides over an inner circumferential surface 21 of the slide bearing 2. A gap G (i.e. a clearance) is formed between the outer circumferential portion 32 of the shaft 3 and the inner circumferential surface 21 of the slide bearing 2.
Inside the shaft 3, a main oil feed hole 5 through which lubricating oil flows is provided in an axial direction. The term “axial direction” here means a direction in which the axis Ax of the shaft 3 extends. The main oil feed hole 5 has a substantially cylindrical shape whose central axis is the axis Ax of the shaft 3 and has an opening at a lower end of the shaft 3 in the axial direction. As the shaft 3 rotates, the lubricating oil flows into the main oil feed hole 5 via the opening. The lubricating oil in the main oil feed hole 5 may flow in the axial direction and be pressure-fed by an oil feed pump or other devices.
Further, the shaft 3 is provided with a columnar branch oil feed hole 6 branching off from the main oil feed hole 5 outward in the radial direction. The branch oil feed hole 6 has an inlet in an inner circumferential surface 33 of the shaft 3 and an outlet 320 in the outer circumferential portion 32 of the shaft 3 so that the gap G between the shaft 3 and the slide bearing 2 and the main oil feed hole 5 communicate with each other. As the shaft 3 rotates, the lubricating oil flowing into the main oil feed hole 5 passes through the branch oil feed hole 6 and is drained via the outlet 320.
The gap G between the outer circumferential portion 32 of the shaft 3 and the inner circumferential surface 21 of the slide bearing 2 is filled with lubricating oil drained from the branch oil feed hole 6 of the shaft 3. Friction between the inner circumferential surface 21 of the slide bearing 2 and the outer circumferential portion 32 of the shaft 3 during rotation of the shaft 3 is reduced by the lubricating oil.
The lubricating oil in the main oil feed hole 5 may contain foreign matter 8 such as abrasion powder. The foreign matter 8 such as abrasion powder is generated, for example, on sliding parts or other parts of the slide bearing 2 and the shaft 3. The foreign matter 8 circulates through the closed vessel of the rotary machine together with the lubricating oil. Therefore, if the foreign matter 8 is supplied directly to the gap between the slide bearing 2 and the shaft 3 without being separated from the lubricating oil, the foreign matter 8 may cause further abrasion to increase in amount.
To address this problem, a structure for separation of foreign matter (hereinafter also referred to as “foreign matter separating portion”) is provided in a flow passage of the lubricating oil up to the supply of the lubricating oil to the gap G between the sliding parts of the slide bearing 2 and the shaft 3. There are three options of where to provide a foreign matter separating portion: a place in the branch oil feed hole 6 of the shaft 3 that is at or close to the outlet 320, a place in the middle of the branch oil feed hole 6, and a place in the branch oil feed hole 6 that is at or close to the inlet. In one configuration, a foreign matter separating portion may be provided in one of the three places. In an alternative configuration, foreign matter separating portions may be provided in two or more of the three places.
In the bearing structure 1 of Embodiment 1, a foreign matter separating portion configured to separate the foreign matter 8 from the lubricating oil is provided in the middle of the branch oil feed hole 6. Specifically, a recessed foreign matter separating space 7a serving as a foreign matter separating portion is provided in an inner wall portion 31a of an inner wall 31 of the branch oil feed hole 6 that is backward in a direction of rotation (direction of an arrow R) and upstream from the outlet 320. In other words, the foreign matter separating space 7a is not connected directly to the main oil feed hole 5 and communicates with the main oil feed hole 5 via part of the branch oil feed hole 6 that is at or close to the inlet, and is not connected directly to the gap G and communicates with the gap G via part of the branch oil feed hole 6 that is at or close to the outlet 320.
A mechanism by which, in a case in which foreign matter 8 is contained in the lubricating oil in the main oil feed hole 5, the foreign matter 8 is separated from the lubricating oil prior to the supply of the lubricating oil to the gap G is described with reference to
Further, in a rotating system of coordinates that rotates at the same angular velocity as the shaft 3, the foreign matter 8 is subjected to not only the centrifugal force but also Coriolis force (indicated by an outline arrow Fc in
Meanwhile, a similar Coriolis force acts on lubricating oil inside the branch oil feed hole 6; however, due to a density difference between the lubricating oil and the foreign matter 8, the Coriolis force acting on the foreign matter 8 is greater than the Coriolis force acting on the lubricating oil. Therefore, the trajectory of the foreign matter 8 indicated by the arrow F2 in the drawing is curved further backward in the direction of rotation than a trajectory of the lubricating oil indicated by an arrow F1 in the drawing, so that the foreign matter 8 and the lubrication oil separate from each other inside the branch oil feed hole 6. Moreover, the foreign matter 8 moving to continuously approach the inner wall portion 31a that is backward in the direction of rotation (direction of the arrow R) enters the foreign matter separating space 7a provided in the inner wall portion 31a and is trapped upstream from the outlet 320.
In the example shown in
The rotor of Embodiment 1 is constituted by the shaft 3, and in the example shown in
As noted above, a bearing structure 1 according to Embodiment 1 includes a rotor having a cylindrical shape and having a main oil feed hole 5 through which lubricating oil passes and that is provided in an axial direction and a slide bearing 2 provided outward in a radial direction with a gap G between the rotor and the slide bearing and configured to hold the rotor so that the rotor rotates around an axis. The rotor is provided with a branch oil feed hole 6 through which the gap G and the main oil feed hole 5 communicate with each other and through which the lubricating oil passes. A foreign matter separating portion (e.g. a foreign matter separating space 7a) configured to separate foreign matter from the lubricating oil is provided further backward in a direction of rotation of the rotor (i.e. further forward in a direction opposite to the direction of rotation) than the branch oil feed hole 6.
According to this configuration, a foreign matter separating portion configured to separate the foreign matter 8 from the lubricating oil is provided further backward in the direction of rotation (direction of the arrow R) than the branch oil feed hole 6. Therefore, even in a case in which foreign matter 8 is contained in lubricating oil flowing through the rotor, the action of inertial force on lubricating oil and foreign matter 8 flowing through the branch oil feed hole 6 is utilized so that foreign matter 8 that is higher in density than the lubricating oil can be separated from the lubricating oil in the foreign matter separating portion. This inhibits foreign matter 8 from being supplied from the branch oil feed hole 6 of the rotor to the gap between the rotor and the slide bearing 2, thus making it possible to further reduce abrasion on sliding parts of the slide bearing 2 and the shaft 3 than has conventionally been the case.
Further, the foreign matter separating portion is a recessed foreign matter separating space 7a provided in an inner wall portion 31a of an inner wall 31 of the branch oil feed hole 6 that is backward in the direction of rotation. According to this configuration, even if foreign matter 8 moves from the main oil feed hole 5 of the rotor to the branch oil feed hole 6 with the flow of lubricating oil, the action of Coriolis force, which is a type of inertial force, on lubricating oil and foreign matter 8 flowing through the branch oil feed hole 6 is utilized so that foreign matter 8 that is higher in density than the lubricating oil can be separated from the lubricating oil by flowing into the foreign matter separating space 7a. This makes it possible to reduce the supply of foreign matter 8 to the sliding parts of the slide bearing 2 and the rotor.
Further, the foreign matter separating space 7a has, in the axial direction, a width that is greater than or equal to a width of at least the branch oil feed hole 6 in the axial direction. This better allows more foreign matter 8 to flow into the foreign matter separating space 7a in the branch oil feed hole 6.
As shown in
As noted above, in the modification shown in
According to this configuration, the foreign matter separating space 7a is constituted by the foreign matter drain hole 32f shown in
As shown in
Embodiment 2 is different from Embodiment 1 in that the shaft 3 is constituted by a plurality of elements so that the branch oil feed hole 6 is divided. In other respects, Embodiment 2 is identical to Embodiment 1. Components of Embodiment 2 that are identical to those of Embodiment 1 are given identical reference signs, and Embodiment 2 is described with a focus on differences from Embodiment 1.
An example configuration of the shaft 3 is described with reference to
The first element 3a has a first planar portion 35a intersecting at a right angle with the center line of the branch oil feed hole 6 and passing through the foreign matter separating space 7a, and the second element 3b too has a second planar portion 35b intersecting at a right angle with the center line of the branch oil feed hole 6 and passing through the foreign matter separating space 7a. The first planar portion 35a and the second planar portion 35b are each a plane substantially parallel to the axis Ax. It should be noted that
First fitting portions 36a constituted, for example, by indented surfaces are formed at both ends of the first planar portion 35a in the first element 3a in a transverse direction, and second fitting portions 36b constituted, for example, by indented surfaces to fit the first fitting portions 36a are formed at both ends of the second planar portion 35b in the first element 3b in a transverse direction. The second fitting portions 36b of the second element 3b form a pair of lugs (not illustrated) provided to wrap around an outer circumferential side of the first element 3a, and by this pair of lugs, the first element 3a is configured not to fall off outward in a radial direction of the second element 3b. The fit between the first fitting portions 36a and the second fitting portions 36b causes the first planar portion 35a of the first element 3a and the second planar portion 35b of the second element 3b to face each other.
Next, a method for manufacturing such a shaft 3 is described. First, as shown in
Further, as shown in
As shown in
After that, the first element 3a and the second element 3b are assembled together so that the first fitting portions 36a of the first element 3a and the second fitting portions 36b of the second element 3b engage with each other, whereby the branch oil feed hole 6 and the foreign matter separating space 7a are formed.
In the manufacturing method, the timing of execution of the step of forming the branch oil feed hole 6 is not limited to the aforementioned timing. For example, the step of forming the branch oil feed hole 6 may be executed prior to the step of separating the shell element into the first element 3a and the second element 3b.
Further, the number of elements that constitute the shaft 3 and the shape of each element that constitutes the shaft 3 are not particularly limited to those noted above.
As shown in
Although not illustrated, the modification of Embodiment 2 is configured such that a lower end portion of the first element 3a and an upper end portion of the second element 3b fit each other, and a lower surface portion of the first element 3a and an upper surface portion 35c of the second element 3b face each other.
In the modification shown in
In a case in which the branch oil feed hole 6 and the foreign matter separating space 7a are each quadrangular in cross-section as shown in
In the example shown in
Further, in the bearing structure 1 according to Embodiment 2, the rotor is constituted by a shaft 3, and the shaft 3 is constituted by a first element 3a including part of the branch oil feed hole 6 and a second element 3b including a remaining part of the branch oil feed hole 6.
This makes it possible to form the foreign matter separating space 7a by performing milling from a division surface (such as the first planar portion 35a) between the first element 3a and the second element 3b, thus eliminating the need for a special device such as a 3D printer and making it possible to avoid an increase in manufacturing cost.
The sleeve 9 is fixed to the shaft 3 and rotates at the same rotation speed as the shaft 3. That is, in Embodiment 3, the sleeve 9 is a mating element that slides over the slide bearing 2, and lubricating oil is supplied to a gap G (see
As shown in
Note here that the statement that the sleeve oil feed hole 62 and the shaft oil feed hole 61 are arranged in a straight line means that as shown in
Although, in
A first outer circumferential recessed portion 32a formed by a recess in the outer circumferential portion 32 of the shaft 3 may be provided backward in the direction of rotation (direction of the arrow R) at an edge of the outlet 320 of the shaft oil feed hole 61. The foreign matter separating space 7a is formed by the first outer circumferential recessed portion 32a of the shaft 3 and an inner circumferential surface 91 of the sleeve 9. That is, in Embodiment 3 too, the foreign matter separating space 7a is provided in the inner wall portion 31a of the inner wall 31 of the branch oil feed hole 6 that is backward in the direction of rotation (direction of an arrow R) and upstream from the outlet 920.
The following describes an example of a method for manufacturing a bearing structure 1 of Embodiment 3. After the sleeve oil feed hole 62 has been formed in the sleeve 9 and the shaft oil feed hole 61 and the first outer circumferential recessed portion 32a have been formed in the shaft 3, the sleeve 9 is fitted and fixed onto the outer circumferential portion 32 of the shaft 3 so that the sleeve oil feed hole 62 and the shaft oil feed hole 61 face each other.
It should be noted that the timing of formation of the branch oil feed hole 6 is not limited to the aforementioned case. For example, after the sleeve oil feed hole 62 and the shaft oil feed hole 61 have been bored from the outer circumferential portion 92 of the sleeve 9 with the sleeve 9 fitted onto the outer circumferential portion 32 of the shaft 3, the sleeve 9 and the shaft 3 may be detached, and the first outer circumferential recessed portion 32a may be formed in the shaft 3.
As noted above, in the bearing structure 1 according to Embodiment 3 too, foreign matter 8 is separated from the lubricating oil in the branch oil feed hole 6 and trapped in the foreign matter separating space 7a; therefore, as in the case of Embodiment 1, an effect of making it possible to further reduce abrasion of sliding parts than has conventionally been the case is brought about.
Further, in Embodiment 3, the rotor is constituted by a cylindrically shaped shaft 3 and a cylindrically shaped sleeve 9 fitted onto an outer circumferential portion 32 of the shaft 3 and configured to rotate with the shaft 3. The branch oil feed hole 6 of the rotor incudes a shaft oil feed hole 61 provided in the shaft 3 and a sleeve oil feed hole 62 provided in the sleeve 9. A first outer circumferential recessed portion 32a formed by a recess in the outer circumferential portion 32 of the shaft 3 is provided backward in the direction of rotation (direction of the arrow R) at an opening edge (edge of the outlet 320) of the shaft oil feed hole 61. The foreign matter separating space 7a is formed by the first outer circumferential recessed portion 32a of the shaft 3 and an inner circumferential surface 91 of the sleeve 9.
According to this configuration, a bearing structure 1 having a foreign matter separating space 7a in the middle of a branch oil feed hole 6 can be manufactured by providing the first outer circumferential recessed portion 32a in the outer circumferential portion 32 of the shaft 3 with the shaft 3 and the sleeve 9 detached from each other and then assembling the shaft 3 and the sleeve 9 together. This makes it possible to easily manufacture the bearing structure 1 without using a special device such as a 3D printer.
Further, in a circumferential direction of the rotor, the sleeve oil feed hole 62 is provided in a location that is identical to that of the shaft oil feed hole 61, and the branch oil feed hole 6 of the rotor is constituted by the shaft oil feed hole 61 and the sleeve oil feed hole 62. This prevents the main flow of lubricating oil from being blocked in the branch oil feed hole 6, thus making it possible to smoothly supply the lubricating oil to the sliding parts while separating the foreign matter 8 into the foreign matter separating space 7a.
In the bearing structure 1 of Embodiment 4 too, as in the case of Embodiment 3, the rotor is constituted by a shaft 3 and a sleeve 9 Note, however, that Embodiment 4 is different from Embodiment 3 in the shape of the branch oil feed hole 6 of the rotor. In the following, a configuration of the bearing structure 1 according to Embodiment 4 is described with reference to
In Embodiment 4, as shown in
A second outer circumferential recessed portion 32b formed by a recess in the outer circumferential portion 32 of the shaft 3 is provided forward in the direction of rotation (direction of the arrow R) at the edge of the outlet 320 of the shaft oil feed hole 61. The oil feed space 63 is formed by the second outer circumferential recessed portion 32b of the shaft 3 and the inner circumferential surface 91 of the sleeve 9. That is, Embodiment 4 is configured such that the outer circumferential portion 32 of the shaft 3 has recesses both backward and forward in the direction of rotation (direction of the arrow R) at the edge of the outlet 320 of the shaft oil feed hole 61.
In the example shown in
The following describes an example of a method for manufacturing a bearing structure 1 of Embodiment 4. The sleeve oil feed hole 62 is formed in the sleeve 9, and the shaft oil feed hole 61 is formed in the shaft 3. Further, the first outer circumferential recessed portion 32a and the second outer circumferential recessed portion 32b are formed by passing the cutting tool 200 in a transverse direction along a plane perpendicular to the center line of the shaft oil feed hole 61 while keeping the cutting tool 200 in contact with the outer circumferential portion 32 of the shaft 3. After that, the sleeve 9 is fitted and fixed onto the outer circumferential portion 32 of the shaft 3 so that the second outer circumferential recessed portion 32b of the shaft 3 and the sleeve oil feed hole 62 face each other.
As noted above, in the bearing structure 1 according to Embodiment 4 too, foreign matter 8 is separated from the lubricating oil in the branch oil feed hole 6 and trapped in the foreign matter separating space 7a; therefore, as in the case of Embodiment 1, an effect of making it possible to further reduce abrasion of sliding parts than has conventionally been the case is brought about.
Further, in Embodiment 4, in a circumferential direction of the rotor, the sleeve oil feed hole 62 is provided further forward in the direction of rotation (direction of the arrow R) than the shaft oil feed hole 61. A second outer circumferential recessed portion 32b formed by a recess in the outer circumferential portion 32 of the shaft 3 is provided forward in the direction of rotation at the opening edge (edge of the outlet 320) of the shaft oil feed hole 61, and an oil feed space 63 is formed by the second outer circumferential recessed portion 32b of the shaft 3 and the inner circumferential surface 91 of the sleeve 9. Moreover, the branch oil feed hole 6 of the rotor is constituted by the shaft oil feed hole 61, the sleeve oil feed hole 62, and the oil feed space 63.
This makes it possible to increase the capacity of a space in which to retain foreign matter 8 upstream from the outlet 920 in the branch oil feed hole 6 and makes it possible to accumulate more foreign matter 8 within the rotor, thus inhibiting foreign matter 8 from flowing outward from the outlet 920. Further, providing the sleeve oil feed hole 62 in a location that is further forward in the direction of rotation (direction of the arrow R) than the shaft oil feed hole 61 sets up a configuration in which the branch oil feed hole 6 is curved frontward in the direction of rotation upstream from the sleeve oil feed hole 62. This inhibits foreign matter 8 from reaching the sleeve oil feed hole 62 by being subjected to greater Coriolis force than the lubricating oil. A reason for this is that in the shaft 3 in rotation, a force in the direction of rotation that is greater than Coriolis force acting in a direction opposite to the direction of rotation does not act on foreign matter 8. Accordingly, in Embodiment 4, the amount of foreign matter 8 that is supplied to the gap G between the slide bearing 2 and the sleeve 9 can be further reduced than in the case of Embodiment 3, in which the branch oil feed hole 6 is provided in a straight line.
In the bearing structure 1 of Embodiment 5 too, as in the case of Embodiment 3, the rotor is constituted by a shaft 3 and a sleeve 9 Note, however, that Embodiment 5 is different from Embodiment 3 in the shape of the shaft 3. In the following, a configuration of the bearing structure 1 according to Embodiment 5 is described with reference to
In Embodiment 5, the shaft 3 includes a crowning portion 3c in which the outer circumferential portion 32 is barreled. The crowning portion 3c is provided in part of the shaft 3 in the axial direction. The sleeve 9 is fitted and fixed onto the outer circumferential portion 32 of the shaft 3 to cover an outer circumferential portion of the crowning portion 3c, and the crowning portion 3c and the sleeve 9 rotate at the same rotation speed. The crowning portion 3c is provided so that the slide bearing 2 and the sleeve 9 maintain a parallel positional relationship with each other even in a case in which the shaft 3 becomes inclined.
The shaft oil feed hole 61 and the first outer circumferential recessed portion 32a are provided in the crowning portion 3c of the shaft 3, and the foreign matter separating space 7a is formed by the first outer circumferential recessed portion 32a provided in the crowning portion 3c and the inner circumferential surface 91 of the sleeve 9. Although
As noted above, in the bearing structure 1 according to Embodiment 5 too, foreign matter 8 is separated from the lubricating oil in the branch oil feed hole 6 and trapped in the foreign matter separating space 7a; therefore, as in the case of Embodiment 1, an effect of making it possible to further reduce abrasion of sliding parts than has conventionally been the case is brought about.
Further, in Embodiment 5, a crowning portion 3c in which the outer circumferential portion 32 of the shaft 3 is barreled is provided in part of the shaft 3 in the axial direction, and the shaft oil feed hole 61 and the first outer circumferential recessed portion 32a are provided in the crowning portion 3c of the shaft 3. Moreover, the sleeve 9 is fitted on the outer circumferential portion 32 of the shaft 3 to cover an outer circumference of the crowning portion 3c. This makes it possible to, even in a case in which the shaft 3 is provided with the crowning portion 3c, apply a configuration in which foreign matter 8 is separated, increasing versatility.
As in the case of Embodiment 5, the bearing structure 1 according to Embodiment 6 too is configured such that the shaft 3 is provided with a crowning portion 3c, that the sleeve 9 is provided to cover an outer circumferential portion of the crowning portion 3c, and that the first outer circumferential recessed portion 32a is provided in the outer circumferential portion of the crowning portion 3c. Note, however, that Embodiment 6 is different from Embodiment 5 in that foreign matter storage grooves 32c and foreign matter drain grooves 32d are provided in the outer circumferential portion 32 of the shaft 3. In the following, a configuration of the bearing structure 1 according to Embodiment 6 is described with reference to
The first outer circumferential recessed portion 32a, the foreign matter storage grooves 32c, and the foreign matter drain grooves 32d are formed in a portion of the outer circumferential portion 32 of the shaft 3 covered with the sleeve 9. The foreign matter storage grooves 32c are circumferentially provided in locations away from the first outer circumferential recessed portion 32a in the axial direction. The foreign matter drain grooves 32d cause the first outer circumferential recessed portion 32a and the foreign matter storage grooves 32c to communicate with each other. Foreign matter 8 trapped in the foreign matter separating space 7a flows into the foreign matter storage grooves 32c via the foreign matter storage grooves 32c and is collected by the foreign matter storage grooves 32c.
In the example shown in
The shapes of the foreign matter drain grooves 32d are determined with reference to the orientation of Coriolis force acting on the foreign matter 8. In the example shown in
In Embodiment 6 too, as in the case of Embodiment 5, the shaft oil feed hole 61 is provided in the crowning portion 3c of the shaft 3. In the example shown in
The foreign matter 8 trapped in the foreign matter separating space 7a by separating from the lubricating oil due to the action of Coriolis force is further collected by flowing from the foreign matter separating space 7a into foreign matter storage grooves 32c through the foreign matter drain grooves 32d due to the action of Coriolis force. In the case of Embodiment 6, the foreign matter 8 does not flow backward from the foreign matter storage grooves 32c into the foreign matter separating space 7a as long as the shaft 3 does not rotate in the opposite direction, as the foreign matter drain grooves 32d are provided.
As noted above, in the bearing structure 1 according to Embodiment 6 too, foreign matter 8 is separated from the lubricating oil in the branch oil feed hole 6 and trapped in the foreign matter separating space 7a; therefore, as in the case of Embodiment 1, an effect of making it possible to further reduce abrasion of sliding parts than has conventionally been the case is brought about.
Further, in Embodiment 6, foreign matter storage grooves 32c provided away from the first outer circumferential recessed portion 32a in the axial direction and foreign matter drain grooves 32d through which the first outer circumferential recessed portion 32a and the foreign matter storage grooves 32c communicate with each other are formed in a portion of the outer circumferential portion 32 of the shaft 3 covered with the sleeve 9.
According to this configuration, foreign matter 8 trapped in the foreign matter separating space 7a is collected in the foreign matter storage grooves 32c, whereby more foreign matter 8 can be retained within the rotor. This makes it possible to reduce the amount of foreign matter 8 that is supplied to the gap G between the slide bearing 2 and the sleeve 9. Furthermore, the foreign matter 8 thus collected can be retained in flow passages that are deeper than the outlet 920, that is, the foreign matter storage grooves 32c. This inhibits foreign matter 8 once trapped in the foreign matter separating space 7a from flowing again into the branch oil feed hole 6, making it possible to more surely reduce the amount of foreign matter 8 that is supplied to the gap G.
Further, a crowning portion 3c in which the outer circumferential portion 32 of the shaft 3 is barreled is provided in part of the shaft 3 in the axial direction, and the shaft oil feed hole 61 and the first outer circumferential recessed portion 32a are provided in the crowning portion 3c of the shaft 3. The sleeve 9 is fitted on the outer circumferential portion 32 of the shaft 3 to cover an outer circumference of the crowning portion 3c, and the foreign matter storage grooves 32c are provided at ends of the crowning portion 3c in the axial direction.
According to this configuration, the shape of the crowning portion 3c can be utilized to provide recesses such as the first outer circumferential recessed portion 32 and the foreign matter drain grooves 32d in the barreled outer circumferential portion of the barreled crowning portion 3c and provide the foreign matter storage grooves 32c at constricted ends of the crowning portion 3c. This makes it possible to easily form a structure in which foreign matter 8 is retained between the crowning portion 3c and the sleeve 9.
As shown in
As shown in
As a method for forming the foreign matter separating space 7a and the oil feed space 63 in continuity in the shaft 3 of the first modification of Embodiment 6, there is for example a method for removing part of the outer circumferential portion of the crowning portion 3c in a circumferential direction by milling as in the case of Embodiment 4.
As noted above, in the first modification of Embodiment 6, in a portion of the outer circumferential portion 32 of the shaft 3 covered with the sleeve 9, foreign matter storage grooves 32c are provided at a distance from the opening edge (edge of the outlet 320) of the shaft oil feed hole 61 and at both ends of the opening edge in the axial direction. The first outer circumferential recessed portion 32a is provided astride two of these foreign matter storage grooves 32c in the axial direction. This makes it unnecessary to provide foreign matter drain grooves 32d, thus simplifying the manufacturing process.
Further, in the first modification of Embodiment 6, in a portion of the outer circumferential portion 32 of the shaft 3 covered with the sleeve 9, foreign matter storage grooves 32c are provided at a distance from the opening edge (edge of the outlet 320) of the shaft oil feed hole 61 and at both ends of the opening edge in the axial direction. The first outer circumferential recessed portion 32a and the second outer circumferential recessed portion 32b are provided in continuity and provided astride two of these foreign matter storage grooves 32c in the axial direction. Moreover, the shaft oil feed hole 61 intersects at an angle with side surfaces 32s of the first outer circumferential recessed portion 32a and the second outer circumferential recessed portion 32b and is inclined backward in the direction of rotation.
This causes lubricating oil containing foreign matter 8 to be released into a space away from the sleeve oil feed hole 62, thus inhibiting the foreign matter 8 from reaching the sleeve oil feed hole 62 by being subjected to greater Coriolis force than the lubricating oil. This results in making it possible to further reduce the amount of foreign matter 8 that is supplied to the gap G.
As shown in
In the third modification, as shown in
Although not illustrated, a foreign matter drain space 32e may be provided in the lower cylindrical portion 3d as well as the cylindrical portion 3d above the shaft oil feed hole 61. Although, in
Further, the shapes of the foreign matter drain grooves 32d of
Furthermore, as shown in
As noted above, in the third modification shown in
As noted above, in a case in which the foreign matter separating space 7a and the foreign matter drain space 32e are provided in the sleeve 9 too, foreign matter 8 trapped in the foreign matter separating space 7a is drained out of the bearing structure through the foreign matter drain space 32e as in the case in which the foreign matter separating space 7a and the foreign matter drain space 32e are provided in the shaft 3. This results in making it possible to further reduce the amount of foreign matter 8 that is supplied to the gap G.
As shown in
While the shaft 3 is rotating, the lubricating oil is suctioned upward in an oil feed direction (direction of an arrow Fo) from a lower end of the shaft 3 into the main oil feed hole 5. The lubricating oil in the main oil feed hole 5 moves upward while generating a swirl flow in the same direction as the direction of rotation (direction of the arrow R) of the shaft 3. Foreign matter 8 present in lubricating oil forming a swirl flow swirls with the lubricating oil. Due to the action of centrifugal force on the foreign matter 8, the foreign matter 8 flows in the same direction as the direction of rotation (direction of the arrow R) of the shaft 3 along the inner circumferential surface 33 of the shaft 3 in part of the main oil feed hole 5 that is far away from the axis Ax. Foreign matter 8 swirling along the inner wall surface (inner circumferential surface 33) of the main oil feed hole 5 is blocked by the wall portion 7b1 of the foreign matter separating wall 7b from moving forward in the direction of rotation and trapped in the space 7a1 that is further backward in the direction of rotation than the entrance of the branch oil feed hole 6.
As noted above, in the bearing structure 1 according to Embodiment 7 too, a foreign matter separating portion in which foreign matter 8 is separated from the lubricating oil is provided further backward in the direction of rotation than the branch oil feed hole 6; therefore, as in the case of Embodiment 1, an effect of reducing abrasion of sliding parts by the foreign matter 8 is brought about.
Further, the bearing structure 1 according to Embodiment 7 includes a foreign matter separating wall 7b extending from an entrance of the branch oil feed hole 6 into the main oil feed hole 5, and a space 7a1 formed further backward in the direction of rotation that the entrance of the branch oil feed hole 6 by the foreign matter separating wall 7b functions as a foreign matter separating portion. This makes it possible to separate foreign matter 8 from lubricating oil and trap the foreign matter 8 upstream of the entrance of the branch oil feed hole 6 in the direction in which the lubricating oil and the foreign matter 8 flow, making it possible to inhibit the foreign matter 8 from being suctioned through the entrance of the branch oil feed hole 6.
The compressor 12 includes a closed vessel 103 constituting an outer shell, a fixed scroll 101, an orbiting scroll 102, and a crank shaft 107 having an eccentric portion 30. The closed vessel 103 is provided with a suction port 109 through which refrigerant is suctioned and a discharge port 110 through which compressed refrigerant is discharged. The crank shaft 107 is equivalent to the aforementioned shaft 3. The crank shaft 107 is configured to transmit, to the orbiting scroll 102, motive power that compresses refrigerant. The fixed scroll 101 and the orbiting scroll 102 each have a spiral tooth shape.
Further, the compressor 12 includes a cylindrically shaped slider 106 and a cylindrically shaped sleeve 9. The slider 106 is fitted on the eccentric portion 30 of the crank shaft 107. The sleeve 9 is fitted in such a place on the crank shaft 107 as to support reaction force that is generated when refrigerant is compressed by rotating the orbiting scroll 102. Further, the compressor 12 includes an orbiting bearing 105 fitted onto the slider 106, a main bearing 104 fitted onto the sleeve 9, a main oil feed hole 5 provided inside the crank shaft 107, and a branch oil feed hole 6 provided astride the crank shaft 107 and the sleeve 9. Further, an oil feed pump 111 is attached to a lower portion of the crank shaft 107. The oil feed pump 111 is caused by rotation of the crank shaft 107 to suck up lubricating oil from an oil sump 108 and send the lubricating oil to the main oil feed hole 5.
As noted above, a compressor 12 according to Embodiment 8 includes the bearing structure 1 and a closed vessel 103 housing the bearing structure 1. This makes it possible to, even if foreign matter 8 present in the oil sump 108 is sent to the main oil feed hole 5 via the oil feed pump 111, inhibit the foreign matter 8 from being supplied to sliding parts of the main bearing 104 and the sleeve 9. This makes it possible to reduce abrasion of the sliding parts, lengthening the life of the compressor 12.
It should be noted that the present disclosure is not limited to being applied to the compressor 12 but may be applied to another rotary machine having a configuration in which lubricating oil is supplied to sliding parts of the rotor and the sliding bearing 2 via the rotor. Further, a refrigeration cycle apparatus 10 to which the compressor 12 of the present disclosure is applied is not limited to the aforementioned air-conditioning cooling equipment.
The refrigerant circuit 11 is formed by the compressor 12, an outdoor heat exchanger 14, a pressure reducing device 15, an indoor heat exchanger 16, or other devices being connected by refrigerant pipes. The compressor 12 is configured to compress refrigerant and cause the refrigerant to circulate through the refrigerant circuit 11. The outdoor heat exchanger 14 and the indoor heat exchanger 16 are configured to cause the refrigerant and air to exchange heat with each other. The pressure reducing device 15 is constituted, for example, by an expansion valve and configured to expand and decompress the refrigerant. Further, in the example shown in
The flow switching device 13 enables switching between cooling and heating. The refrigeration cycle apparatus 10 includes a controller (not illustrated) configured to control various actuators. The controller controls, for example, the frequency of the compressor 12, the opening degree of the pressure reducing device 15, and the switching of the flow switching device 13. During cooling operation, as indicated by solid arrows in
It should be noted that the configuration of the refrigerant circuit 11 is not limited to the aforementioned configuration. For example, the flow switching device 13 may be omitted.
A refrigeration cycle apparatus 10 according to Embodiment 8 includes a refrigerant circuit 11 in which the compressor 12, an evaporator (e.g. an indoor heat exchanger 16), a pressure reducing device 15, and a condenser (e.g. an outdoor heat exchanger 14) are connected via refrigerant pipes. According to this configuration, including the compressor 12 with a reduction in abrasion on sliding parts by foreign matter 8 brings about improvement in reliability of the refrigeration cycle apparatus 10.
1: bearing structure, 2: bearing, 3: shaft, 3a: first element, 3b: second element, 3c: crowning portion, 3d: cylindrical portion, 5: main oil feed hole, 6: branch oil feed hole, 6a: branch oil feed wall inner wall, 7a: foreign matter separating space, 7a1: space, 7b: foreign matter separating wall, 7b1: wall portion, 7c: foreign matter separating wall forming element, 8: foreign matter, 9: sleeve, 10: refrigeration cycle apparatus, 11: refrigerant circuit, 12: compressor, 13: flow switching device, 14: outdoor heat exchanger, 15: pressure reducing device, 16: indoor heat exchanger, 21: inner circumferential surface, 30: eccentric portion, 31: inner wall, 31a: inner wall portion, 32: outer circumferential portion, 32a: first outer circumferential recessed portion, 32b: second outer circumferential recessed portion, 32c: foreign matter storage groove, 32d: foreign matter drain groove, 32e: foreign matter drain space, 32f: foreign matter drain hole, 32fo: exit, 320: outlet, 32r: inner wall portion, 32s: side surface, 33 inner circumferential surface, 35a: first planar portion, 35b: second planar portion, 35c: upper surface portion, 36a: first fitting portion, 36b: second fitting portion, 61: shaft oil feed hole, 62: sleeve oil feed hole, 63: oil feed space, 91: inner circumferential surface, 92: outer circumferential portion, 920: outlet, 101: fixed scroll, 102: orbiting scroll, 103: closed vessel, 104: main bearing, 105: orbiting bearing, 106: slider, 107: crank shaft, 108: oil sump, 109: suction port, 110: discharge port, 111: oil feed pump, 200: cutting tool, Ax: axis, G: gap
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-134809 | Aug 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/024058 | 6/16/2022 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2023/021829 | 2/23/2023 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20160047381 | Tanaka et al. | Feb 2016 | A1 |
| Number | Date | Country |
|---|---|---|
| 102021122169 | Mar 2023 | DE |
| S53-007708 | Jan 1978 | JP |
| 2003-042080 | Feb 2003 | JP |
| 2004-162837 | Jun 2004 | JP |
| 2009-167849 | Jul 2009 | JP |
| 2015-161209 | Sep 2015 | JP |
| 2014155923 | Oct 2014 | WO |
| WO-2017145281 | Aug 2017 | WO |
| Entry |
|---|
| International Search Report and Written Opinion mailed on Aug. 2, 2022, received for PCT Application PCT/JP2022/024058, filed on Jun. 16, 2022, 9 pages including English Translation. |
| Notice of Reasons for Refusal mailed on Mar. 14, 2023, received for JP Application 2022-578668, 10 pages including English Translation. |
| Number | Date | Country | |
|---|---|---|---|
| 20250101985 A1 | Mar 2025 | US |
