Waveform retainer

Abstract

[Problem] To provide a waveform retainer having no possibility of being damaged even when used for a ball bearing of a scroll type electric compressor or the like, having no high difficulty of press working, and hardly causing deformation when balls are inserted into pocket parts. [Solution] Provided is a waveform retainer 1 composed of one waveform annular member 2. The annular member 2 is composed of: pocket parts 3 each having an inlet 5 into which a ball G, serving as a rolling element of a ball bearing, enters from an axial direction J and having a substantially U-shape when viewed in a radial direction; and flat plate parts 4 connecting inlet-side end parts 6 of the adjacent pocket parts 3. The pocket parts 3 have: first pocket parts A in each of which the space of the inlet 5 is smaller than the diameter of the ball G; and second pocket parts B in each of which the space of the inlet 5 is larger than the diameter of the ball G. The first pocket parts A are not adjacent to each other in the circumferential direction.

Description

Waveform retainer

[0001] The present invention relates to a waveform retainer used for ball bearings, and particularly to a waveform retainer suitable for use as a ball bearing for a scroll type electric compressor or the like.

[0002] As a retainer used for a ball bearing, there is a waveform retainer using a waveform annular member formed by performing punching and bending processes on a steel plate by pressing (see, for example, Patent Documents 1 and 2).

[0003] The waveform retainer 5 of Patent Document 1 has a pair of waveform annular members 10. The annular member 10 has a plurality of concave pocket portions 11 for holding balls 4 that are rolling elements, and flat plate portions 12 that connect adjacent pocket portions 11. The waveform retainer 5 of Patent Document 1 abuts a pair of annular members 10 in the axial direction, forms a pocket 17 for accommodating the balls 4 in the opposing pocket portions 11 of the annular member 10, and inserts a rivet 20 into the through-hole 13 of the flat plate portion 12 and caulks the axial ends.

[0004] On the other hand, the waveform retainer 5 of Patent Document 2 consists of one waveform annular member, so rivets are unnecessary. The waveform retainer 5 of Patent Document 2 has a pocket portion 7 that wraps around the balls 4 that are rolling elements, and flat plate portions 8 that connect adjacent pocket portions 7, and the shape of the pocket portion 7 is an arc that exceeds 180 degrees and is less than 360 degrees.

[0005] Japanese Patent Application Laid-Open No. 2017-48834 German Patent Application Publication No. 102017110180 Specification

[0006] For example, in a scroll type electric compressor that can be made more compact and whose scroll rotation speed can be arbitrarily controlled, when a ball bearing is used as the bearing between the bush fitted and fixed to the eccentric shaft and the movable scroll body, a state occurs where a load intermittently acts on the balls that are rolling elements or does not act. As a result, the revolution speed of a specific ball changes rapidly, causing excessive forward and backward movement of the ball, and thus a collision occurs between the ball and the retainer that holds the ball (see, for example, paragraphs

[0004] -

[0008] of Patent Document 1).

[0007] In a corrugated retainer 5 having a pair of corrugated annular members 10 and rivets 20, such as in Patent Document 1, repeated forces act to separate the mating surfaces of the flat plate portions 12 of the pair of annular members 10 due to the collision, so it is necessary to take measures to prevent damage to the annular members 10 and rivets 20 due to fatigue.

[0008] Therefore, in the retainer 5 of Patent Document 1, as a measure to prevent the aforementioned damage, the peripheral edge 14 of the through hole 13 formed in the flat plate portion 12 of the pair of annular members 10 is formed to be thicker than the surrounding portion 15, as shown in Figure 3 of Patent Document 1. This avoids interference between the crimping jig and the retainer 5 during the riveting process of the corrugated retainer 5, and allows the use of rivets 20 with the largest possible radial size.

[0009] However, as explained with reference to Figures 2 and 3 of Patent Document 1, in the corrugated retainer 5 of Patent Document 1, it is difficult to press-form the peripheral edge 14 of the through hole 13 of the flat plate portion 12 to be thicker than the surrounding portion 15, and there are limitations on the size of rivets that can be used. Therefore, it is difficult to manufacture, and the risk of rivet breakage due to the aforementioned collision remains.

[0010] A corrugated retainer 5 consisting of a single corrugated annular member, as described in Patent Document 2, has a pocket portion 7 shaped like an arc exceeding 180 degrees but less than 360 degrees, and holds one ball 4 in one pocket portion 7. Therefore, since there are no mating surfaces of the flat portions of the pair of annular members and no rivets connecting and fixing the pair of annular members, there is no need to take measures to prevent the aforementioned damage.

[0011] However, in the corrugated metal holder 5 of Patent Document 2, the shape of all pocket portions 7 is an arc exceeding 180 degrees but less than 360 degrees, and all pocket portions 7 are structured to hold the ball 4 in the axial direction. Therefore, when press-molding the corrugated metal holder 5, it is necessary to forcibly remove all pocket portions 7, making the processing difficult.

[0012] Furthermore, in the assembly of the ball bearing 1 shown in Figure 3 of Patent Document 2, when inserting the balls 4 into the corrugated retainer 5, it is necessary to elastically deform all the pocket portions 7 shown in Figure 1 of Patent Document 2 to insert the balls 4. Therefore, there is a risk that the stress acting on the flat plate portions 8 between adjacent pocket portions 7 may deform the corrugated retainer 5 itself.

[0013] The present invention aims to provide a corrugated retainer that is not prone to damage when used in ball bearings of scroll-type electric compressors, is not difficult to press-form, and is less likely to deform when balls are inserted into the pocket.

[0014] The corrugated retainer according to the present invention is a corrugated retainer consisting of a single corrugated annular member. The annular member consists of a substantially U-shaped pocket portion in radial view having an entrance into which balls, which are rolling elements of a ball bearing, enter from the axial direction, and a flat plate portion connecting the entrance-side ends of adjacent pocket portions. The pocket portion has a first pocket portion in which the distance between the entrances is smaller than the diameter of the ball, and a second pocket portion in which the distance between the entrances is larger than the diameter of the ball, and the first pocket portions are not adjacent in the circumferential direction.

[0015] In this embodiment, the distance between the openings of the first pocket when the ball is not inserted is preferably 94% to 99% of the diameter of the ball.

[0016] With this type of corrugated retainer configuration, since it consists of a single corrugated annular member rather than a pair of corrugated annular members connected and fixed with rivets, there is no risk of damage even when used in ball bearings of scroll-type electric compressors and the like that rotate and revolve simultaneously.

[0017] Furthermore, the roughly U-shaped pocket portion in radial view has a first pocket portion where the distance between the entrances into which the ball enters from the axial direction is smaller than the diameter of the ball, and a second pocket portion where the distance between the entrances is larger than the diameter of the ball, and the first pocket portions are not adjacent in the circumferential direction. Therefore, it is not necessary to forcibly form the entire pocket portion, and only the first pocket portions that are not adjacent in the circumferential direction need to be forcibly formed, so the difficulty of processing is not high.

[0018] Furthermore, since the spacing between the entrances of the second pocket is greater than the diameter of the ball, there is no need to elastically deform the second pocket when inserting the ball into the second pocket, and it is sufficient to elastically deform the first pocket when inserting the ball into the first pocket which is not adjacent in the circumferential direction. Therefore, deformation of the corrugated retainer is less likely to occur when the ball is inserted into the pocket.

[0019] As described above, the corrugated retainer of the present invention does not risk damage even when used in ball bearings of scroll-type electric compressors, is not difficult to press-form, and is less prone to deformation when balls are inserted into the pocket.

[0020] Figure 1 is a perspective view showing a corrugated metal holder and a ball held in the holder according to an embodiment of the present invention. Figure 1 is a plan view of the corrugated metal holder and ball. Figure 1 is a front view of the corrugated metal holder and ball. Figure 1 is a partial cross-sectional view of the first pocket portion and ball of the corrugated metal holder in Figure 1, taken from the rotational axis side, of a cross-section obtained by cutting the ball through a cylindrical plane including the pitch circle diameter of the ball. Figure 1 is a partial cross-sectional view of the second pocket portion and ball of the corrugated metal holder in Figure 1, taken from the rotational axis side, of a cross-section obtained by cutting the ball through a cylindrical plane including the pitch circle diameter of the ball. Figure 4 is a partial cross-sectional view corresponding to Figure 4, showing the state before the ball is inserted into the first pocket portion.

[0021] The corrugated retainer according to the present invention is suitable for use in ball bearings that rotate while revolving, such as those used in scroll-type electric compressors or planetary gear mechanisms. Embodiments of the present invention will be described below with reference to the drawings.

[0022] In this specification, the direction parallel to the rotational axis of a ball bearing (for example, see reference numeral O in Figures 1 and 2) is called the "axial direction" (for example, see arrow J in Figures 1 and 3), and the direction perpendicular to the rotational axis is called the "radial direction" (for example, see arrow R in Figures 1 and 2). The radial direction approaching the rotational axis is called the "radial inward direction" (for example, see arrow RI in Figure 2), and the radial direction moving away from the rotational axis is called the "radial outward direction" (for example, see arrow RO in Figure 2). A "circumferential direction" (for example, see arrow C in Figure 2) is defined with respect to the direction of the rotational axis. Furthermore, a view from the radial outward direction is called a front view.

[0023] [Waveform Holder] As shown in Figure 1-3, the waveform holder 1 consists of a single wave-shaped annular member 2. The annular member 2 consists of a pocket portion 3 that is roughly U-shaped in radial R view and has an entrance 5 into which the balls G, which are rolling elements of the ball bearing, enter from the axial direction J, and a flat plate portion 4 that connects the entrance-side ends 6 of adjacent pocket portions 3. The pocket portions 3 form pockets P for holding the balls G and are arranged equally in the circumferential direction C, for example. In this embodiment, multiple pocket portions 3 are arranged equally in the circumferential direction C, but depending on the specifications of the ball bearing, multiple pocket portions 3 may be arranged unequally in the circumferential direction C.

[0024] The corrugated retainer 1 is formed from an iron plate (SPCC, SUS, etc.) by press working. The formed corrugated retainer 1 may be strengthened by heat treatment or nitriding treatment, or its sliding properties may be improved by surface treatment.

[0025] [Pocket section] The pocket section 3 has a first pocket section A in which the spacing E1 of the entrances 5 is smaller than the diameter D of the ball G (E1 < D), as shown in Figure 4, and a second pocket section B in which the spacing E2 of the entrances 5 is larger than the diameter D of the ball G (E2 > D), as shown in Figure 5.

[0026] [Arrangement of the First and Second Pockets] As shown in Figure 1-2, the first pocket A is not adjacent to any other pocket A in the circumferential direction C. When the number of balls G and pockets 3 is odd, as shown in Figure 1-2, there is one second pocket B adjacent to a ball in the circumferential direction C. When the number of balls G and pockets 3 is even, neither the first pocket A nor the second pocket B is adjacent to any other pocket B in the circumferential direction C. That is, when the number of balls G and pockets 3 is even, the first pocket A and the second pocket B are arranged alternately in the circumferential direction C.

[0027] [Evaluation of the numerical range of the entrance spacing of the first pocket section by analysis] The spacing of the entrances 5 in the state before inserting the ball G into the first pocket section A shown in Figure 6 was defined as E0, and the change in the spacing of the entrances 5 when inserting the ball into the first pocket section A was determined by analysis. The above analysis was an elastoplastic analysis that took springback into consideration, and was performed with no balls G inserted into the second pocket sections B adjacent to the first pocket section A. The spacing of the entrances 5 E1 in the state with the ball G inserted into the first pocket section A shown in Figure 4 may widen due to plastic deformation when the ball G is inserted into the first pocket section A, resulting in E1 > E0.

[0028] Let (E1 - E0) / E0 be the percentage change in the distance of the entrance 5 after inserting ball G into the first pocket A.

[0029] The "entrance interval" is defined as the percentage (E0 / D) × 100 (%) obtained by normalizing E0 by the diameter D of the ball G. For cases 1 to 8 (93.50% to 99.50%) in Table 1, the percentage of the rate of change [(E1 - E0) / E0] × 100 (%) is determined by the above analysis.

[0030] (Determination Method) If the percentage of the change is 0.3% or less, it is considered "acceptable" (within the specified range under the product's usage conditions), and if the percentage of the change exceeds 0.3%, it is considered "unacceptable" (outside the specified range under the product's usage conditions). However, even if the percentage of the change is 0.3% or less, it will be considered "unacceptable" if it is undesirable in terms of ball G falling out or functional specifications.

[0031]

[0032] (Judgment Results) The judgment results are shown in Table 1. Case 1 ("Inlet spacing" is 93.5%) is "Unacceptable" when the percentage of the change in the inlet spacing exceeds 0.3%, and Case 8 ("Inlet spacing" is 99.5%) is "Unacceptable" when it is undesirable due to ball G falling out or functional standards.

[0033] In cases 2 to 7, that is, when the "inlet spacing" is between 94% and 99%, the percentage of the change is 0.3% or less, and therefore it is within the standard range under the product's usage conditions. Furthermore, it is not undesirable in terms of ball G falling out or functional standards, and is therefore judged as "acceptable."

[0034] Based on the above, a preferred embodiment is one in which the spacing E0 of the entrance 5 of the first pocket A in the state where the ball G shown in Figure 6 is not inserted is 94% to 99% of the diameter D of the ball G (0.94D ≤ E0 ≤ 0.99D).

[0035] [Effects] According to the configuration of the corrugated retainer 1 according to the embodiment of the present invention, it consists of a single corrugated annular member 2, and a substantially U-shaped pocket portion 3 in radial view, which has an entrance 5 into which the balls G, which are rolling elements of a ball bearing, enter from the axial direction J, is held in place of the annular member 2. Therefore, compared to a configuration consisting of a pair of corrugated annular members and rivets as in Patent Document 1, the number of parts can be reduced and the rivet crimping process can be reduced.

[0036] Furthermore, the configuration of the corrugated retainer 1 is not one in which a pair of corrugated annular members are connected and fixed with rivets, as in Patent Document 1, but rather consists of a single corrugated annular member 2. Therefore, there is no risk of damage even when used in ball bearings of scroll-type electric compressors and the like that revolve while rotating on their own axis.

[0037] Furthermore, according to the configuration of the corrugated retainer 1, the pocket portion 3, which is roughly U-shaped in radial view, has a first pocket portion A (Figure 4) where the distance E1 of the entrances 5 into which the ball G enters from the axial direction J is smaller than the diameter D of the ball D, and a second pocket portion B (Figure 5) where the distance E2 of the entrances 5 is larger than the diameter D of the ball G, and the first pocket portion A is not adjacent in the circumferential direction C (Figure 2). Therefore, as in Patent Document 2, it is not necessary to forcibly form the entire pocket portion 3, and it is sufficient to forcibly form only the first pocket portion A that is not adjacent in the circumferential direction C, so the difficulty of processing is not high.

[0038] Furthermore, according to the configuration of the waveform holder 1, the spacing E2 of the entrance 5 of the second pocket B is larger than the diameter D of the ball G (Figure 5). Therefore, when inserting the ball G into the second pocket B, it is not necessary to elastically deform the second pocket B. When inserting the ball G into the first pocket A, which is not adjacent in the circumferential direction C, it is sufficient to elastically deform the first pocket A. Thus, deformation of the waveform holder 1 is less likely to occur when inserting the ball G into the pocket 3.

[0039] All embodiments described above are illustrative and not limiting. Various improvements and modifications can be made without departing from the scope of the present invention.

[0040] 1. Corrugated retainer 2. Annular member 3. Pocket section 3A. Inner surface 4. Flat section 5. Entrance 6. Entrance side end A. First pocket section B. Second pocket section C. Circumferential direction D. Ball diameter E0. Distance of entrances before inserting a ball into the first pocket section E1, E2. Distance of entrances G. Ball J. Axial direction O. Rotational center axis P. Pocket R. Radial direction RI. Radial inward RO. Radial outward

Claims

1. A corrugated retainer comprising a single corrugated annular member, wherein the annular member comprises a substantially U-shaped pocket portion in radial view having an entrance into which balls, which are rolling elements of a ball bearing, enter from the axial direction, and a flat plate portion connecting the entrance-side ends of adjacent pocket portions, the pocket portion having a first pocket portion where the distance between the entrances is smaller than the diameter of the ball, and a second pocket portion where the distance between the entrances is larger than the diameter of the ball, and the first pocket portions are not adjacent in the circumferential direction.

2. The waveform holder according to claim 1, wherein the distance between the openings of the first pocket when the ball is not inserted is 94% to 99% of the diameter of the ball.

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