JP3931991B2 - Shoe - Google Patents

Description

The present invention relates to a shoe, and more particularly to a shoe that is used in, for example, a swash plate compressor and slides with a swash plate.

Conventionally, as a swash plate compressor, a compressor including a swash plate provided rotatably and a shoe having a sliding surface sliding with the swash plate is known (for example, Patent Document 1 and Patent Document 2).
Japanese Patent Laid-Open No. 10-153169 JP 2002-317757 A

By the way, the above-described conventional swash plate compressor has recently been used under conditions of high speed and high load and a small amount of lubricating oil. Thus, recently, the operating conditions of swash plate compressors have become increasingly severe, and as a result, the swash plate and shoes wear more seriously, and there is a problem that they are likely to be seized.
Furthermore, in order to improve the sliding characteristics of the shoe, the surface of the sliding surface of the shoe has been subjected to surface treatment and modification. There was a drawback that the cost was high.

In view of the circumstances described above, the present invention provides a shoe having a sliding surface that slides with a swash plate.
A hardened portion consisting of a large number of minute annular bulges is formed on the sliding surface, and the radially inner side of each of the annular bulges is a recess capable of storing lubricating oil. On the radially outward side of the bulging portion, a lubricating oil passage made of a mesh-like concave portion through which lubricating oil can flow is formed,
Furthermore, when the area of the quenching target region forming the annular bulging portion is S1, and the total area of all the annular bulging portions is S2, the convex area ratio as a value of S2 / S1 is 0.45. The annular bulging portion is formed so as to be 0.8.

  According to such a configuration, as is apparent from the test results described later, a shoe having better seizure resistance than the conventional one can be provided.

The present invention will be described below with reference to the illustrated embodiment. In FIG. 1, a sliding device 1 is provided in a housing of a swash plate compressor. The sliding device 1 includes a swash plate 3 that is attached to a rotating shaft 2 that is pivotally supported in the housing, and a plurality of shoes 4 that slide on the swash plate 3.
The swash plate 3 is formed in a disc shape, and both end surfaces of the swash plate 3 are flat sliding surfaces 3 A and 3 A that slide with the shoe 4.
On the other hand, the shoe 4 is formed in a hemispherical shape as a whole, and is composed of a sliding surface 4A that slides on the sliding surface 3A of the swash plate 3 and a hemispherical convex surface 4B that has a hemispherical shape.

In the housing of the swash plate compressor, a plurality of pistons 5 are arranged in parallel to and surrounding the rotary shaft 2. A pair of two shoes 4 is slidably held in an arc-shaped cutout 5A formed at one end of each piston 5, and the cutout 5A in this state is attached to the outer peripheral portion of the swash plate 3. Simultaneously with the arrangement, the sliding surfaces 4A of each pair of shoes 4 are brought into contact with the sliding surfaces 3A of the swash plate 3.
When the rotary shaft 2 is rotated, the swash plate 3 rotates, and the sliding surfaces 3A, which are both end surfaces of the swash plate 3, and the sliding surfaces 4A of the shoes 4 of each set slide, and accordingly. Thus, each piston 5 is moved back and forth in the axial direction via each pair of shoes 4.
The configuration described above is not different from that of a conventionally known sliding device.

Therefore, the shoe 4 of this embodiment is made of SUJ2 which is an iron-based material, and the substantially flat sliding surface 4A consisting of an end surface has a medium-high shape whose center side is slightly raised (about 2 μm) from the outer peripheral edge. ing. Thus, when the sliding surface 4A slides with the sliding contact surface 3A of the swash plate 3, the lubricating oil is easily drawn between the sliding surfaces 4A and 3A.
In this embodiment, the seizure resistance of the sliding surface 4A is improved by irradiating and irradiating a laser as described later with the entire sliding surface 4A of the shoe 4 as the quenching target region.

That is, the process of quenching on the sliding surface 4A in this embodiment will be described. First, as shown in FIGS. 2 to 3, the sliding surface 4A of the shoe 4 (base material) manufactured using SUJ2 as a material is shown. The YAG laser is irradiated so as to draw a large number of circles 6 having the same diameter with the entire region as the quenching target region.
The diameter of each circle 6 is set to 0.8 mm, and each circle 6 is positioned at each intersection when assuming virtual parallel lines having the same vertical and horizontal pitches P over the entire sliding surface 4A. The circle 6 is drawn around each intersection. In this embodiment, the pitch P is set to 1.1 mm, and the quenching width B by irradiating the sliding surface 4A with laser so as to draw the circle 6 is set to 0.3 mm. .
The output of the YAG laser irradiating the sliding surface 4A is 50 W, and the condenser lens is set so that the YAG laser is focused at a position 2 mm deep with respect to the surface of the sliding surface 4A. Therefore, the YAG laser is irradiated in a defocused state on the surface of the sliding surface 4A.

As shown in FIGS. 4 and 5, the locations of the respective circles 6 on the sliding surface 4 </ b> A irradiated with the laser in this way bulge into an annular bulging portion 7, and the radial bulging portion 7 in the radial direction is formed. A taper-shaped recess 8 whose bottom is constricted is formed on the adjacent inner side. That is, by irradiating the sliding surface 4A with a laser so as to draw the circles 6, the crater-like annular bulging portion 7 is formed at the location of the circle 6 irradiated with the laser. Further, on the radially outward side of each annular bulging portion 7, a mesh-like concave portion 10 that communicates with each other and reaches the outer peripheral portion of the sliding surface 4 </ b> A is formed.
Each annular bulging portion 7 and its inner portion 11 in the depth direction (a portion above the broken line 9) have a hardness of about Hv100 with respect to Hv750 which is the hardness of the base material of the shoe 4. Quenching has been done.
On the other hand, the radially inward side of each annular bulging portion 7 and the outer side of the annular bulging portion 7 (location of the concave portion 8 and the mesh-shaped concave portion 10) on the sliding surface 4A are annealed and are not quenched. The hardness of the portion is lower than that of the base material by about Hv100.

In the present embodiment, by irradiating the laser as described above with the entire sliding surface 4A of the shoe 4 as the quenching target region, first, a large number of minute annular bulging portions 7 and concave portions 8 and mesh-shaped concave portions 10 are formed. Form.
After that, all the annular bulging portions 7 on the sliding surface 4A are temporarily deleted by lapping to make the sliding surface 4A smooth, and then the sliding surface 4A is buffed and processed. Ends.
After the processing is completed in this manner, as shown in FIG. 6, the annular bulge is formed at each circle 6 (the annular bulging portion 7) irradiated with the laser over the entire sliding surface 4A. An annular bulging portion 7 ′ similar to the portion 7 is formed, and a concave portion 8 ′ similar to the concave portion 8 is formed radially inward of each annular bulging portion 7 ′. Furthermore, a lubricating oil passage 10 'formed of a mesh-shaped recess through which the lubricating oil can flow is formed outward of each annular bulging portion 7' in the radial direction.
This is because the initial annular bulging portion 7 is deleted by lapping, and then buffing is performed, so that the hardness of the inner portion 11 in the depth direction of the annular bulging portion 7 is the peripheral portion thereof. Therefore, the annular bulging portion 7 ′, the concave portion 8 ′, and the lubricating oil passage 10 ′ are formed by leaving the high hardness portion in the annular shape.
In the present embodiment, a quenching portion is formed by a large number of annular bulging portions 8 ′ formed in this way. Each recess 8 'functions as a reservoir for storing the lubricating oil, and the lubricating oil can flow in the lubricating oil passage 10'.
In this embodiment, as described above, the sliding surface 4A is laser-quenched and then lapped and then buffed, but the axial direction of the sliding surface 4A by lapping and buffing is used. Since the grinding amount is about several μm, there is substantially no change in the area of the sliding surface 4A.

Further, as shown in FIG. 6, the height h of each annular bulge 7 ′ (depth of the recess 8 ′) is 0.1 to 0.3 μm, and the maximum width W of the cross section of the annular bulge 7 ′ ( The radial dimension of the hem is about 0.3 mm. That is, the quenching width of the annular bulging portion 7 ′ as the quenching portion is about 0.3 mm. Moreover, the diameter D1 of the peak part of each annular bulging part 7 ′ is 0.8 mm, which is the same as the diameter of the circle 6 at the time of laser irradiation. As shown in FIG. 7, the outer diameter DL of the annular bulging portion 7 ′ is about 1.1 mm, and the inner diameter D0 of the annular bulging portion 7 ′ is about 0.5 mm.
In this embodiment, the total area of the sliding surface 4A, which is the quenching target region when irradiating the laser, is S1, and the total of all the annular bulging portions 7 ′ formed on the sliding surface 4A. The annular bulging portion 7 'is formed so that the value of S2 / S1 as the convex portion area ratio is 0.3 to 0.8 when the area of S2 is S2. In other words, in this embodiment, the ratio of the total area of the portion (annular bulging portion 7 ′) actually laser-quenched to the area of the quenching target region (the area of the sliding contact surface 4A) is 0.3-0. .8.
In addition, in the said Example, although the whole sliding surface 4A is made into the hardening object area | region, as illustrated in FIGS. 10-12, the principal part of the sliding surface 4A is made into the hardening object area | region, and the above-mentioned in the area | region As described above, the annular bulging portion 8 ′ may be formed by irradiating a laser. In this case, the area of the minimum virtual circle or virtual frame surrounding the quenching target area is the area of the quenching target area.
In the present embodiment shown in FIG. 2 in which the entire area of the sliding surface 4A is the quenching target area, the circle 12 serving as the outline of the sliding surface 4A is the smallest virtual circle surrounding the quenching target area.
As can be seen from the test results described later, according to this embodiment, the seizure resistance of the shoe 4 can be improved. Further, according to the test results conducted by the inventors of the present application, in order to obtain better seizure resistance of the shoe 4, the annular bulge is formed so that the area ratio of the convex portion is 0.45 to 0.8. It is desirable to form part 7 '.

FIG. 8 shows the difference in the convex area ratio when the pitch P shown in FIG. 3 is different from the inner diameter D0 of the annular bulging portion 7 ′ as the shoe 4 of this embodiment.
FIG. 9 shows the test results of the seizure surface pressure performed on the shoe 4 of the present embodiment including the one illustrated in FIG. 8 and the normal shoe as the prior art.
Here, in the shoe of the prior art, the sliding surface is not laser-hardened, and the sliding surface is a flat surface. The swash plate as the counterpart material was also made of a brass material containing Mn and Si in the shoes of the prior art and this example. Test conditions for seizure resistance are as follows.
(Test conditions)
Swash plate rotation speed: 1000 rpm increments by 9 steps per minute: Maximum rotation speed 9000 rpm (circumferential speed 38 m / s)
Surface pressure: Increased by 2.7 MPa in 1 minute increments with preload of 2.7 MPa: Until seizure Oil mist amount: 0.05 to 0.25 g / min Nozzle position fixed Oil: Refrigerating machine oil Seizure condition: Shaft torque 4.0 N · m over That is, with the sliding surface 4A of the shoe 4 in pressure contact with the swash plate 3, the rotational speed of the swash plate 3 is increased under the above conditions. On the other hand, the surface pressure when the shoe 4 was pressed against the swash plate 3 was increased under the above conditions, and it was determined that seizure occurred when the axial torque applied to the swash plate 3 exceeded 4.0 N · m. The same applies to the prior art.

A black circle in FIG. 9 shows the shoe 4 of the present example. When the convex area ratio is larger than 0.3, good seizure resistance is obtained, and in particular, the convex area ratio. In the range from 0.45 to the upper limit of 0.8, the seizure surface pressure is 19.1 MPa or more, and extremely good seizure resistance is obtained. Here, the upper limit means a state in which adjacent annular bulging portions 7 ′ are formed on the sliding surface 4 </ b> A in the most dense state without interfering with each other.
On the other hand, those indicated by white circles in FIG. 9 show the test results of conventional normal products, and all are 5 MPa or less.
As is apparent from the test results shown in FIG. 9, the shoe 4 of this example has superior seizure resistance compared to the conventional one. As can be understood from the test results shown in FIG. 9, the area ratio of the annular bulging portion 7 ′ is preferably 0.46 to 0.8 in order to obtain better seizure resistance.
Further, on the sliding surface 4A of the shoe 4 of the present embodiment, a plurality of annular bulging portions 7 ′ are formed, and a concave portion 8 ′ for storing lubricating oil is formed radially inward thereof. Lubricating oil is stored in these recesses 8 '. In addition, a lubricating oil passage 10 'formed of a mesh-shaped recess is formed at an outer position adjacent to each annular bulging portion 7'. Therefore, the load capacity of the sliding surface 4A of the shoe 4 can be improved, and as a result, the shoe 4 having excellent wear resistance can be provided.

In the above-described embodiment, the entire area of the sliding surface 4A of the shoe 4 is set as an area to be quenched by the laser, and the annular bulging portion 7 ′ is formed therein. However, when sliding with the swash plate 3, A required region where the pressure is increased may be set as a region to be quenched by laser, and the annular bulging portion 7 ′ may be formed there.
That is, as shown in FIG. 10, even if the inner side of the virtual circle 21 on the center side is set as the quenching target region except for the outer peripheral region on the sliding surface 4A, a large number of annular bulge portions 7 ′ are formed there. good. Further, as shown in FIG. 11, a donut-shaped portion divided by large and small virtual circles 22 and 23 on the center side of the sliding surface 4A is used as a quenching target region, and a large number of annular bulge portions 7 'are formed there. You may do it. Furthermore, as shown in FIG. 12, an annular bulging portion 7 ′ may be formed on a required portion in the circumferential direction on the sliding surface 4 </ b> A as a quenching target region.
As shown in FIGS. 10 to 12, even when the annular bulge 7 ′ is formed only in the quenching target region that is a part of the sliding surface 4 </ b> A, the convex area ratio is within the above-described range (0 .3 to 0.8) can provide the shoe 4 having good seizure resistance.

In each of the above embodiments, each annular bulging portion 7 'is formed at the intersection of vertical and horizontal parallel lines. However, as shown in FIG. 13, the annular bulging portions 7' are formed in a staggered manner. Also good.
In the above-described embodiment, the diameters of the circles when irradiating the sliding surface 4A with the laser are all the same diameter. However, as shown in FIG. The annular bulging portion 7 ′ may be formed by drawing a circle having a smaller diameter than the other one (center position in FIG. 14).
Further, as shown in FIG. 15, the annular bulging portion 7 ′ may be formed by irradiating the sliding surface 4A with a laser so as to draw an ellipse .
In the above-described embodiment, SUJ2 is used as the material for the shoe 4. However, the present invention is not limited to this, and other iron-based materials may be used.
Furthermore, the above-described annular bulging portion or bulging portion may be formed by irradiating the sliding surface with an electron beam instead of the laser quenching by the above-described laser irradiation to perform quenching.

Sectional drawing which shows one Example of this invention. FIG. 2 is a front view of a sliding surface of the shoe shown in FIG. 1. The enlarged view of the principal part in the manufacture process of the shoe shown in FIG. The enlarged view of the principal part of FIG. Sectional drawing which follows the VV line | wire of FIG. Sectional drawing of the principal part which follows the VI-VI line of FIG. The enlarged plan view of the principal part of FIG. The figure which illustrated the convex part area ratio. The figure which shows the test result of a prior art and a present Example. The front view of 4 A of sliding surfaces which show the other Example of this invention. The front view of 4 A of sliding surfaces which show the other Example of this invention. The front view of 4 A of sliding surfaces which show the other Example of this invention. The enlarged front view of the principal part of the sliding surface which shows the other Example of this invention. The enlarged front view of the principal part of the sliding surface which shows the other Example of this invention. The front view of the cyclic | annular bulging part which shows the other Example of this invention .

Explanation of symbols

3 ... Swash plate 4 ... Shoe 4A ... Sliding surface 7 '... Annular bulging part (hardened part)

Claims (4)

In a shoe with a sliding surface that slides with a swash plate,
A hardened portion consisting of a large number of minute annular bulges is formed on the sliding surface, and the radially inner side of each of the annular bulges is a recess capable of storing lubricating oil. On the radially outward side of the bulging portion, a lubricating oil passage made of a mesh-like concave portion through which lubricating oil can flow is formed,
Furthermore, when the area of the quenching target region forming the annular bulging portion is S1, and the total area of all the annular bulging portions is S2, the convex area ratio as a value of S2 / S1 is 0.45. The above-mentioned annular bulging portion is formed so as to be 0.8. Each of the annular bulges is formed by irradiating the surface of the base material with a laser so as to draw a large number of minute circles, then lapping the surface of the base material and then buffing the base material. The shoe according to claim 1, wherein: The annular swelling portion, claim 1 or claim 2, characterized in that it is formed at a position of an intersection of the staggered or horizontal and vertical parallel lines with respect to the required range of the entire or the sliding surface of the sliding surface Shoe. The shoe according to claim 1 , wherein the annular bulging portion is formed by irradiating a sliding surface with a laser or an electron beam.

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