JP2017172736A - Resin-made cage for bearing, manufacturing method of the same and rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin-made cage for a bearing excellent in strength on a weld part and to provide a manufacturing method of the same or the like.SOLUTION: An annular resin-made cage for a bearing is an injection molding body of resin composition, and includes a plurality of pocket parts 4 which retain rolling bodies, pillar parts of axial direction located between respective pocket parts and annular parts which fix the pillar parts on both sides in the axial direction. Therein, on a portion of at least one side of the pillar parts and the annular parts, weld lines are provided on one portion or a plurality of portions of circumferential directions, shapes near the weld lines of the portions are asymmetrical with respect to cross-sections X along the weld lines, for example, on a cage outer side end surface of the annular part, a plurality of thinning parts 3 formed at a regular interval in a circumferential direction and ribs 2 formed between the thinning parts 3 are provided, the weld lines are located on the ribs 2 and shapes of the ribs 2 have uneven thickness of circumferential direction in a radial direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cage for a rolling bearing used in railway vehicles, automobiles, industrial machines and the like. In particular, the present invention relates to a resin cage formed by injection molding a resin composition and a method for manufacturing the same. The present invention also relates to a rolling bearing using the resin cage.

  In the rolling bearing, rolling elements such as balls and cylindrical rollers are arranged in a raceway space between an inner ring and an outer ring, and these rolling elements are held by a cage. Conventionally, metal materials such as high-strength brass have been used for bearing cages. Metal cages are heavy, and wear is generated in the bearing during use, accelerating the deterioration of the lubricant. Therefore, from the viewpoint of extending the life and weight of the bearing (lubricant), the cage is being made of a synthetic resin material. However, it is inferior in strength to metal cages such as high-strength brass, and moreover, resin cages are generally manufactured by injection molding, but this gives dimensional accuracy compared to metal material machining. Is difficult.

  In the case of manufacturing an annular cage using a resin material by injection molding, as shown in FIG. 9, a molten resin 17 is injected into a mold cavity 16 through a runner 18 and a gate 19 with high pressure. Go. At this time, the molten resin 17 injected from the gate 19 into the mold cavity 16 is branched in a complicated manner, and joined again after moving the same distance to form a molten resin joint called a weld 20.

  Conventionally, various proposals have been made for resin cages as methods for ensuring the strength and accuracy of such welds. For example, Patent Document 1 proposes a cage that makes it easy to ensure accuracy such as roundness and cylindricity by disposing the gate portion in the center in the axial direction of the column portion. In Patent Document 2, in a cage in which a gate part and a weld part are located in separate pillar parts, a corner part of the pocket part is adjusted and a pillar part in which the gate part is located and a pillar part in which the weld part is located. A cage having improved breakage resistance has been proposed. Patent Document 3 proposes a cage in which the strength of the weld portion is improved by optimizing the orientation of the reinforcing fiber material.

JP 2002-5176 A JP 2011-52784 A JP 2012-87890 A

  FIG. 10 shows an example of a conventional resin cage for bearings manufactured by injection molding. The cage 11 includes a plurality of pocket portions 12 for holding rolling elements, an axial column portion 13 formed between the pocket portions 12, and an annular portion 14 for fixing the column portions 13 on both sides in the axial direction. And comprising. Gates 15 that are equally distributed in the circumferential direction are provided in the inner diameter portion of the pillar portion 13, and the resin injected from the gate 15 into the mold cavity forms a weld portion (weld line) at the broken line portion of the figure. The gate 15 is disposed at the center in the axial direction of the column portion 13 (see Patent Document 1).

  There are various types of the gate 15 described above, those provided on the inner diameter side of the arbitrary column portion 13, those provided on the annular portion 14 instead of the column portion 13 (both tunnel gates), and gates on the end face of the cage. (Side gate), and an annular gate continuous to the annular portion 14 (disc gate). Depending on the number and position of the gate, the number and position of the weld line will differ even for cages of the same shape, but the common thing is that the colliding resins are bonded with sufficient strength to improve the strength of the weld. It is to be.

  Since the resin is injected into the cavity space at a high pressure, if the inflow speed is too high, the air in the cavity is rapidly compressed, and the bond between the resins at the weld portion is weakened and the weld strength is reduced. On the other hand, if the inflow rate of the resin is too slow, the resin is cooled before reaching the weld, and the bond between the resins is weakened. In general, as shown in FIG. 11A, the resin bites in firmly, and the weld area increases as the bonding area increases. On the other hand, as shown in FIG. 11 (b), if the fluidity of the tip of the resin to be bonded is deteriorated due to a decrease in temperature, when the resins collide with each other at the weld portion, they do not sufficiently bite each other. Becomes weaker. In addition, the arrow in FIG. 13 shows the flow of resin.

  For molds with complex cavities such as cages for bearings, it is not easy to secure the required weld strength (tensile strength) for the usage conditions, and how to improve this strength Is an important issue. In order to avoid an increase in manufacturing cost, it is desired to improve the strength by simpler means.

  This invention is made | formed in view of such a background, and it aims at providing the resin-made cage for bearings which is excellent in the intensity | strength in a weld part, and its manufacturing method. It is another object of the present invention to provide a rolling bearing using the resin cage.

  The bearing resin cage of the present invention is an annular bearing resin cage that is an injection molded body of a resin composition, and the cage includes a plurality of pocket portions that hold rolling elements, An axial column located between the pockets, and an annular portion for fixing the column on both sides in the axial direction, and at least one portion of the column and the annular portion It has a weld line at one or a plurality of locations in the direction, and the shape of the portion in the vicinity of the weld line is asymmetric with respect to a cross section along the weld line.

  A plurality of thinned portions formed at equal intervals in the circumferential direction and ribs formed between the thinned portions on the outer end surface of the annular portion of the cage, and the weld line is formed on the ribs. And the rib shape is (1) circumferential thickness is non-uniform in the radial direction, (2) circumferential thickness is non-uniform in the axial direction, and (3) axial thickness. Is at least one of non-uniform in the radial direction.

  A plurality of thinned portions formed at equal intervals in the circumferential direction and ribs formed between the thinned portions on the outer end surface of the annular portion of the cage, and the weld line is formed on the ribs. One of the meat thinning portions located and adjacent to the rib has at least one of a convex portion protruding from the surface constituting the meat thinning portion and a concave portion recessed from the surface constituting the meat thinning portion. It is characterized by.

  The resin composition is a resin composition obtained by blending glass fiber or carbon fiber with a polyamide resin.

  The manufacturing method of the resin cage for bearings of the present invention is a method for manufacturing the above cage of the present invention, and is equally spaced in the circumferential direction with respect to the mold cavity of the shape of the cage. The resin composition is injection-filled and molded from a plurality of gates provided.

  In this manufacturing method, two or more gates having different resin flow rates are provided as the gate. Further, the plurality of gates are provided in each of the pillar portions, and two or more gates having different axial positions in the respective pillar portions are provided as the gates.

  In this manufacturing method, as the gate, (1) two or more gates having different angles with respect to the mold cavity of the directly connected runner, and (2) two or more gates having different diameter dimensions of the directly connected runner One of the above is provided.

  The rolling bearing of the present invention is a rolling bearing having a rolling element and a cage for holding the rolling element, wherein the cage is a resin cage for bearings of the present invention.

  The bearing resin cage of the present invention includes a plurality of pocket portions for holding rolling elements, axial column portions positioned between the pocket portions, and an annular portion for fixing the column portions on both sides in the axial direction. And at least one of the pillar part and the annular part has a weld line at one or more places in the circumferential direction, and the shape of the part in the vicinity of the weld line extends along the weld line. Since the cross section is asymmetric with respect to the cross section, the flow of the molten resin in the weld portion can be disturbed during injection molding, and the joining area can be increased, so that a cage excellent in the strength of the weld portion can be obtained.

  On the outer end surface of the annular portion of the cage, there are a plurality of thinned portions formed at equal intervals in the circumferential direction, and a rib formed between the thinned portions, and the weld line is positioned on the rib. The rib shape is as follows: (1) circumferential thickness is non-uniform in radial direction, (2) circumferential thickness is non-uniform in axial direction, and (3) axial thickness is non-uniform. Since it is at least one of non-uniform in the radial direction, it can be manufactured only by slightly changing the shape of a conventional rib. For this reason, the strength of the weld portion can be improved without increasing the manufacturing cost.

  On the outer end surface of the annular portion of the cage, there are a plurality of thinned portions formed at equal intervals in the circumferential direction, and a rib formed between the thinned portions, and the weld line is positioned on the rib. In addition, since one of the meat thinning portions adjacent to the rib has at least one of a convex portion projecting from the surface constituting the meat thinning portion and a concave portion recessed from the surface constituting the meat thinning portion, Manufacture can be performed only by applying a slight shape change to the meat thinning portion. For this reason, as described above, the strength of the weld portion can be improved without increasing the manufacturing cost.

  Since the resin composition is a resin composition obtained by blending glass fiber or carbon fiber with polyamide resin, the moldability is excellent, the cage strength is excellent, and the weight can be further reduced.

  In the method for manufacturing a resin cage for a bearing according to the present invention, since two or more gates having different resin flow rates such as different hole diameters are provided as gates, the amount of resin injected and filled from each gate is balanced. It can be broken down and the flow of the molten resin in the weld portion can be disturbed, and the strength of the weld portion can be improved. In addition, as the gate, two or more gates having different axial positions in each column portion, two or more gates having different angles with respect to the mold cavity of the directly connected runner, and the diameter dimension of the directly connected runner By providing two or more different gates, the strength of the weld portion can be improved in the same manner.

  Since the rolling bearing of the present invention uses the resin cage for bearings of the present invention, it is possible to prevent the occurrence of problems such as breakage of the cage at the weld portion while employing the resin cage.

It is a top view which shows a general resin cage. It is a partially expanded view etc. which show an example of the resin cages of this invention. It is a partially expanded view which shows the other example of the resin cage of this invention. It is a partially expanded view etc. which show the other example of the resin cage of this invention. It is a partially expanded view etc. which show the other example of the resin cage of this invention. It is a figure which shows an example of a gate shape and a position. It is a figure which shows an example of the injection filling structure. It is sectional drawing which shows an example of the rolling bearing of this invention. It is a figure which shows the flow of resin in the metal mold | die cavity at the time of injection molding. It is a perspective view which shows the conventional resin cage. It is a schematic diagram which shows the mode of resin in a weld part. It is a figure which shows the outline | summary of a cage tensile testing machine. It is a figure which shows the flow analysis result of a weld line.

  The bearing resin cage will be described with reference to FIG. FIG. 1A is a perspective view of an annular retainer, and FIG. 1B is a plan view of a retainer having ribs and thinned portions on the outer end face of the retainer. As shown in FIG. 1A, an annular resin cage 1 ′ includes a plurality of pocket portions 4 that hold rolling elements and a column portion 6 that is positioned between the pocket portions 4 along the axial direction. And an annular portion 5 for fixing the column portion 6 on both sides in the axial direction. Since the gates 7 that are equally distributed in the circumferential direction are provided in the inner diameter portion of the column portion 6, a weld portion (weld line) is formed at the circumferential center position of the portion that constitutes each pocket portion 4 in the annular portion 5. (Same location as FIG. 10).

  The resin cage 1 '' shown in FIG. 1 (b) has the same overall configuration as the cage shown in FIG. 1 (a), while the meat thinning portion 3 and the meat thinning portions 3 are arranged on the cage end face. Ribs 2 are formed between the two. In general, in injection molding, it is preferable to make the resin passage cross-sectional area in the mold cavity substantially constant. When the resin cage 1 ′ as shown in FIG. 1 (a) is manufactured by injection molding, the annular portion becomes too thick, so that the thinning is performed by performing the thinning as shown in FIG. 2 (b). On the other hand, the rib 2 is formed as described above because it is desired to secure a bonding area as much as possible in the weld portion while the portion 3 is formed. That is, the weld line is located in the rib 2 portion.

  In order to improve the strength of the weld part in the resin cage, it is important how the high temperature resin is bonded in a disordered state in the weld part, and it is also important to increase the bonding area. In order to achieve this, in the cage of the present invention, the shape in the vicinity of the weld line such as a rib is set to be asymmetric with respect to the cross section along the weld line. Due to this asymmetrical shape, the flow of the resin in the welded portion is disturbed, the bonding area is increased, or a combination thereof can provide a high bonding force. In addition, the cross section along a weld line is formed as a surface which divides | segments an annular part or a column part in the circumferential direction by employ | adopting the gate of equal distribution in the circumferential direction. Hereinafter, specific details of the shape will be described with reference to FIGS.

An example of the resin cage for bearings of the present invention will be described with reference to FIG. FIG. 2 is an enlarged view (FIG. 2 (a)) and a perspective view (FIG. 2 (b)) around the rib and the thinned portion in the resin cage. The rib 2 shown in FIG. 2 (a) is formed between two thinned portions 3 among a plurality of thinned portions 3 formed at equal intervals in the circumferential direction, and the thickness in the circumferential direction is a diameter. The direction is non-uniform. Specifically, the thickness of the rib 2 in the axial direction is constant, the outer diameter side wall thickness t _wo is set smaller than the inner diameter side wall thickness t _wi , and the rib 2 has one surface 2a. The other surface 2b is inclined so as to expand in the circumferential direction toward the inner diameter side. The weld line in the cage 1 is located at the approximate center of the rib 2 in the circumferential direction. The rib 2 has an asymmetric shape with respect to the cross section X along the weld line.

Another example of the resin cage for bearings of the present invention will be described with reference to FIG. 3 (a) and 3 (b) are enlarged views of the periphery of the rib and the fillet portion in each resin cage, and FIG. 3 (a) is a view of the annular portion viewed from the outer diameter direction. FIG. 3B is a view of the weld cross section viewed from the circumferential direction. The rib 2 shown in FIG. 3 (a) is formed between two thickened portions 3 among a plurality of thickened portions 3 formed at equal intervals in the circumferential direction, and the thickness in the circumferential direction is axial. The direction is non-uniform. Specifically, the radial thickness of the rib 2 is constant, the wall thickness t _we on one end surface side is set smaller than the wall thickness t _wm on the other end surface side, On the other hand, the other surface 2b is inclined so as to expand in the circumferential direction toward the other end surface. The rib 2 has an asymmetric shape with respect to a cross section along the weld line.

In addition, the rib 2 shown in FIG. 3B has a non-uniform axial thickness in the radial direction. Specifically, the thickness of the rib 2 in the circumferential direction is constant, the outer diameter side thickness t _do is set smaller than the inner diameter side thickness t _di , and the rib 2 surface 2c is on the inner diameter side. The shape is inclined so as to spread in the axial direction.

  In each form shown in FIG. 2 and FIG. 3, by making the thickness of the end face ribs unequal with respect to the circumferential direction, the radial direction, and the axial direction, the flow of the resin in the weld portion is disturbed, or the bonding area To increase the strength at the weld.

  Another example of the resin cage for bearings of the present invention will be described with reference to FIG. FIG. 4A is an enlarged view of the periphery of the rib and the thinned portion in the resin cage, and FIG. 4B is a cross-sectional view taken along line A-A ′ in FIG. The rib 2 shown in FIG. 4 is formed between two meat thinning portions 3 among a plurality of meat thinning portions 3 formed at equal intervals in the circumferential direction. The rib 2 itself is a rib having a normal shape. Here, in the surface 3b which comprises the meat thinning part 3 adjacent to the rib 2, the recessed part 3c recessed from this surface is provided. The recess 3c becomes a protrusion in the cavity at the time of injection molding, obstructs the flow of the molten resin, and can disturb the flow at the weld portion formed at the position of the rib 2. In addition, you may provide this recessed part 3c in the surface 3a which comprises the meat thinning part 3. FIG.

  Another example of the resin cage for bearings of the present invention will be described with reference to FIG. FIG. 5A is an enlarged view of the periphery of the rib and the thinned portion in the resin cage, and FIG. 5B is a cross-sectional view taken along the line B-B ′ in FIG. The rib 2 shown in FIG. 5 is a rib having a normal shape as in FIG. Here, in the surface 3a which comprises the meat thinning part 3 adjacent to the rib 2, the convex part 3d which protrudes from this surface is provided. This convex part 3d becomes a sudden expansion part in the cavity at the time of injection molding, and can disturb the flow at the weld part formed at the position of the rib 2. In addition, you may provide this convex part 3d in the surface 3b which comprises the meat thinning part 3. FIG.

  In each form shown in FIG. 4 and FIG. 5, a cross-section along the weld line formed in the rib has a shape near the weld line by providing a concave portion or a convex portion in the thinned portion adjacent to the rib. As a result, the shape becomes asymmetric. In the mold cavity, the concave portion becomes a protrusion and the convex portion becomes a rapidly expanding portion, and the strength in the weld portion is improved by inducing disturbance of the flow of the molten resin.

  2 to 5 may be provided alone or in combination. Further, it is only necessary that the weld line be positioned on the rib, and the position of the gate may be provided in either the column portion or the annular portion. The number of gates can also be set as appropriate. As the gate method, a tunnel gate, a side gate, a disk gate, or the like can be provided as appropriate in accordance with the formation position.

  The manufacturing method of the resin cage for bearings of the present invention is a method for manufacturing the cage of the present invention as described above. For a mold cavity having a cage shape including the above-mentioned non-uniform ribs, for example, a molten resin of a predetermined resin composition from a plurality of gates provided at equal intervals in the circumferential direction in a portion that becomes a pillar portion Injection molded. The mold used in this manufacturing method is composed of a fixed mold (fixed-side mold) and a movable mold (movable-side mold) that can be clamped and opened with respect to the fixed mold. The mold cavity is formed by the fixed mold and the movable mold that are clamped. In addition, about the pocket part of an annular | circular shaped holder | retainer, it can also form with the metal mold | die using a slide core.

  It was confirmed that the tensile strength was improved as a result of carrying out molding by adjusting the resin passage flow rate of several gates out of the total number of gates in the test cage to be smaller than that of other gates. For this reason, it is considered that the balance of the resin injected into the cavity is intentionally changed, whereby disturbance in the weld portion can be induced and the strength of the weld portion can be improved. Hereinafter, the details of a specific form will be described based on FIG. 6 and FIG.

  An example of the gate shape and position in the manufacturing method of the resin cage for bearings of the present invention will be described with reference to FIG. FIG. 6A shows an example of the gate shape, and FIG. 6B shows an example of the gate position. In addition, all are the figures which looked at the holder | retainer from the internal diameter side. In the example shown in FIG. 6A, equally spaced gates 7a and 7b are arranged in the circumferential direction on the inner diameter portions of the plurality of column portions 6, and the respective gate diameter dimensions are different. There may be two or more gates having different gate diameters, and all the gates may have different diameters. In the example shown in FIG. 6B, equally-spaced gates 7a and 7b are arranged in the circumferential direction on the inner diameter portions of the plurality of column portions 6, and the axial positions of the respective column portions 6 are different. Similar to the above, it is sufficient that there are two or more gates having different axial positions in each column portion, and all the gates may have different axial positions.

  An example of the injection filling structure in the manufacturing method of the resin cage for bearings of the present invention will be described with reference to FIG. 7A and 7B, the molten resin passes through the spool 8a, and then passes through the runner 8b and is injected and filled into the mold cavity 10 through the gate 9. In the example of FIG. 7A, the angles of the runners 8b and 8c directly connected to the gate 9 are different. Thereby, the direction of the resin injected into the mold cavity 10 can be made non-uniform. Moreover, in the example of FIG.7 (b), the diameter dimension of runners 8b and 8c differs. As a result, due to the difference in the cavity cross-sectional reduction ratio of the runner / gate, the disturbance in the weld portion can be induced by the difference in the state of the resin injected from each gate 9. It is sufficient that there are two or more gates with different runner structures directly connected as described above, and all the gates may have different runner structures.

  6 and 7 may be provided alone or in combination. Moreover, you may provide these forms in combination with the form of said FIGS. 2-5 suitably.

  The resin composition used as the material for the resin cage for bearings of the present invention can be used as long as it can be injection-molded and has sufficient heat resistance and mechanical strength as the cage material. . Examples of the synthetic resin used as the base resin of the resin composition include polyamide 6 (PA6) resin, polyamide 6-6 (PA66) resin, polyamide 6-10 (PA610) resin, polyamide 6-12 (PA612) resin, Polyamide (PA) resin such as polyamide 4-6 (PA46) resin, polyamide 9-T (PA9T) resin, polyamide 6-T (PA6T) resin, polymetaxylene adipamide (polyamide MXD-6) resin, injection molding Fluorine resin, polyethylene (PE) resin such as low density polyethylene, high density polyethylene, ultra high molecular weight polyethylene, polyacetal (POM) resin, polyphenylene sulfide (PPS) resin, polyether ether ketone (PEEK) resin, polyamideimide ( PAI) resin, polyetherimide PEI) resins, and injection moldable polyimide (PI) resin. Among these synthetic resins, it is preferable to use PA resin because of excellent heat resistance and injection moldability. Each of these synthetic resins may be used alone or a polymer alloy in which two or more kinds are mixed.

  In addition, in order to improve the mechanical strength such as the elastic modulus of the cage, these resin compositions have glass fibers, aramid fibers, carbon fibers, various mineral fibers (whiskers), etc. as long as they do not impair the injection moldability. It is preferable to blend the fibrous reinforcing material. In particular, glass fibers or carbon fibers are preferably blended because they are excellent in reinforcing effect and availability. As a compounding range of a fibrous reinforcement, it is about 15 to 40 weight% with respect to the whole resin composition, for example. In addition, additives other than the fibrous filler can be blended within a range that does not impair the function and injection moldability of the cage.

  The rolling bearing of the present invention is a bearing using the above-described resin cage for bearings of the present invention. An example of the rolling bearing of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view of a rolling bearing (cylindrical roller bearing). As shown in FIG. 8, the rolling bearing 31 includes an inner ring 32 having an inner ring raceway surface 32a on the outer periphery, an outer ring 33 having an outer ring raceway surface 33a on the inner periphery, and an inner ring raceway surface 32a and an outer ring raceway surface 33a. A plurality of cylindrical rollers 34, which are rolling elements that roll, and a resin cage 1 that holds the cylindrical rollers 34 at equal intervals in the circumferential direction with pocket portions. This resin cage 1 is the bearing resin cage of the present invention. This rolling bearing can prevent problems such as breakage of the cage in the weld. Further, by adopting a resin cage, it is possible to extend the life of the lubricant and reduce the weight of the bearing.

  In addition, although the retainer for cylindrical roller bearings was illustrated in FIG. 8, if it is the shape which has a weld part at the time of injection molding, it can apply also to other arbitrary bearings (for example, needle roller bearing etc.).

Example 1
A cage having the shape shown in FIG. 2 (the overall shape is shown in FIG. 1A) was formed using a resin molding pellet in which glass fiber was blended with 25% by weight of PA66 resin. The gate at the time of injection molding is in the center of the inner diameter part of the column part, and a weld part (weld line) is formed at the center in the circumferential direction of the part constituting each pocket part of the annular part. In order to confirm the tensile strength of the weld portion of the cage, a cage tensile test was performed using the produced cage. As shown in FIG. 12, the cage tensile test is performed using a test apparatus 22 having a tension jig 23 having a semi-circular jig 24 and a tension jig 23 'having a semi-circular jig 24'. The retainer 21 was set in the apparatus so that the weld portion was in a horizontal position, and was performed at a predetermined tensile speed. Note that FIG. 12A is a cross-sectional view taken along the line CC ′ in FIG.

Comparative Example 1
A cage was produced under the same material and under the same conditions as in Example 1 except that the shape of the rib of the cage was changed to the conventional shape (FIG. 1B), and the tensile strength of the weld portion was confirmed.

  As a result of the test, it was confirmed that Example 1 was superior to Comparative Example 1 in the tensile strength of the weld portion. The tensile strength of Example 1 was about 110% compared to Comparative Example 1.

  Moreover, the result of the flow analysis at the time of injection molding on the same conditions as Example 1 is shown in FIG. From this result, it was confirmed that a left and right uneven weld line was formed with respect to the center of the rib.

  Since the resin cage for bearings of the present invention is excellent in strength at the weld portion, it can be suitably used as a cage for rolling bearings used in railway vehicles, automobiles, industrial machines and the like.

DESCRIPTION OF SYMBOLS 1 Resin cage 2 Rib 3 Thinning part 4 Pocket part 5 Ring part 6 Column part 7 Gate 8a Spool 8b Runner 9 Gate 10 Mold cavity 11 Cage 12 Pocket part 13 Column part 14 Ring part 15 Gate 16 Gold Mold cavity 17 Molten resin 18 Runner 19 Gate 20 Weld part 21 Cage (test piece)
22 Test Equipment 23 Tension Jig 24 Semicircle Jig 31 Rolling Bearing 32 Inner Ring 33 Outer Ring 34 Cylindrical Roller

Claims (9)

A resin cage for an annular bearing, which is an injection molded body of a resin composition,
The cage includes a plurality of pocket portions for holding rolling elements, an axial column portion positioned between the pocket portions, and an annular portion for fixing the column portion on both sides in the axial direction.
At least one part of the pillar part and the annular part has a weld line at one or more places in the circumferential direction, and the shape of the part in the vicinity of the weld line is a cross section along the weld line. A bearing cage made of resin, which is asymmetric with respect to the bearing. A plurality of meat thinning portions formed at equal intervals in the circumferential direction and ribs formed between the meat thinning portions on an outer end face of the annular portion of the cage, and the weld line includes the ribs. Located in
The shape of the rib is (1) circumferential thickness is non-uniform in radial direction, (2) circumferential thickness is non-uniform in axial direction, and (3) axial thickness is radial. 2. The resin cage for a bearing according to claim 1, wherein the cage is at least one of non-uniform. A plurality of meat thinning portions formed at equal intervals in the circumferential direction and ribs formed between the meat thinning portions on an outer end face of the annular portion of the cage, and the weld line includes the ribs. Located in
One of the meat thinning portions adjacent to the rib has at least one of a convex portion protruding from a surface constituting the meat thinning portion and a concave portion recessed from a surface constituting the meat thinning portion. The resin-made cage for bearings according to claim 1 or 2.   4. The resin cage for a bearing according to claim 1, wherein the resin composition is a resin composition obtained by blending a glass fiber or a carbon fiber with a polyamide resin. It is a manufacturing method of the resin-made cage for bearings according to any one of claims 1 to 4,
A resin cage for bearings, characterized in that the resin composition is injected and filled from a plurality of gates provided at equal intervals in the circumferential direction into a mold cavity having the shape of the cage. Production method.   6. The method of manufacturing a resin cage for a bearing according to claim 5, wherein two or more gates having different resin passage flow rates are provided as the gate.   The plurality of gates are provided at positions where the pillars are formed, and two or more gates having different axial positions in the pillars are provided as the gates. The manufacturing method of the resin-made cage for bearings of description.   As the gate, either (1) two or more gates having different angles with respect to the mold cavity of the directly connected runner, and (2) two or more gates having different diameter dimensions of the directly connected runner are provided. The method for manufacturing a resin cage for a bearing according to claim 5, 6 or 7. A rolling bearing having a rolling element and a cage for holding the rolling element,
A rolling bearing, wherein the cage is a resin cage for bearings according to any one of claims 1 to 4.