CN111536145A - A kind of plastic-coated bearing and its production method - Google Patents

Abstract

The invention belongs to the field of bearings, and particularly relates to a plastic-coated bearing and a manufacturing method thereof. The wheel body design through will wrap the plastics bearing is for having the structure of first plastic body and second plastic body, and first plastic body and second plastic body can be moulded plastics twice to it is less to make the first plastic body of moulding plastics time gum volume, can effectually avoid leading to the mounting hole excessively to reduce (excessively extrudeing the bearing) in the first plastic body cooling process. Furthermore, when the first plastic body is independently injected, the first plastic body can be injected into a more compact structure, so that the hardness, impact resistance, friction resistance and other performances of the plastic coated bearing wheel body are improved. The second plastic body is designed to be coated outside the first plastic body, so that the bearing, the first plastic body and the second plastic body form the plastic-coated bearing with a stable and firm structure.

Description

A kind of plastic-coated bearing and its production method

technical field

The invention belongs to the field of door and window hardware accessories, and particularly relates to a plastic-coated bearing and a manufacturing method thereof.

Background technique

Plastic-coated bearings generally refer to a layer of plastic on the outside of the bearing. The plastic materials are generally nylon PA, polyoxymethylene POM and engineering plastics polypropylene and PP. Outsourcing plastic has certain hardness, impact resistance, friction resistance and certain self-lubrication. Plastic-coated bearings are widely used in machinery and equipment, industrial assembly lines, furniture and hardware accessories. According to different application purposes, the shape of the plastic-coated bearing can be made into different shapes, such as pulleys with grooves, rollers without grooves, etc.

The existing manufacturing method of the plastic-covered bearing is to use the injection molding process to directly inject an outer plastic layer outside the bearing. Increasing the injection pressure can make the outer plastic layer denser (higher density), thereby improving the hardness, impact resistance, friction resistance and other properties of the outer plastic layer; however, excessive injection pressure will cause the outer plastic layer to be injected. The increase in the amount of glue and the increase in the amount of glue injection will lead to the excessive shrinkage of the outer plastic layer during the cooling process, which will cause the bearing to be stuck or locked due to excessive extrusion of the bearing. Therefore, it is difficult to improve the hardness, impact resistance, friction resistance and other properties of the outer plastic layer of the existing plastic-covered bearing.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a plastic-coated bearing and a manufacturing method thereof in view of the above-mentioned defects of the prior art, so as to solve the hardness, impact resistance, friction resistance and other properties of the outer plastic layer of the existing plastic-coated bearing. Difficult to improve and other defects.

The technical solution adopted by the present invention to solve the technical problem is to provide a plastic-coated bearing, which includes a bearing and a wheel body arranged outside the bearing, and the wheel body includes:

a first plastic body, a mounting hole is formed on the first plastic body, and the bearing is fixed in the mounting hole;

A second plastic body, the second plastic body is wrapped outside the first plastic body.

A further preferred solution of the present invention is that: the first plastic body is further formed with one or more auxiliary holes, the auxiliary holes penetrate through the first plastic body; the second plastic body includes filling the auxiliary holes the filling part and the outer covering part covering the first plastic body.

A further preferred solution of the present invention is that: the auxiliary hole communicates with the mounting hole on the hole wall of the mounting hole.

A further preferred solution of the present invention is that the auxiliary hole completely penetrates the hole wall of the mounting hole in the axial direction, so that the hole wall of the mounting hole forms a broken section of hole wall or multiple sections of hole wall spaced apart from each other.

A further preferred solution of the present invention is that: the first plastic body has a convex ring in the middle of the outer side surface, the second plastic body is provided with an annular track groove on the outer side, and the convex ring is located at the bottom of the annular track groove.

A further preferred solution of the present invention is that a concave-convex anti-detachment structure is provided between the outer side surface of the first plastic body and the second plastic body.

A further preferred solution of the present invention is that: the anti-detachment structure includes an annular groove disposed on the outer side surface of the first plastic body and symmetrically disposed with respect to the annular protrusion, and an annular groove disposed on the second plastic body and disposed symmetrically with respect to the annular protrusion. An annular snap ring clamped in the annular snap groove.

A further preferred solution of the present invention is that: a plurality of bosses are formed at the end of the first plastic body, and the second plastic body also fills the area between the plurality of bosses.

A further preferred solution of the present invention is that: the end face of the boss is flush with the surface of the second plastic body filling the area between the bosses.

Another technical solution adopted by the present invention to solve the technical problem is to provide a manufacturing method of a plastic-coated bearing, comprising the following steps:

injecting a first plastic body to form a mounting hole on the first plastic body;

Fix the bearing into the mounting hole;

A second plastic body is injection molded so that the second plastic body covers the first plastic body.

A further preferred solution of the present invention is: when the first plastic body is injection molded, one or more auxiliary holes are further formed on the first plastic body, and the auxiliary holes pass through the first plastic body; injection molding When the second plastic body is formed, the second plastic body is also filled with the one or more auxiliary holes.

A further preferred solution of the present invention is that: when the first plastic body is injection molded, the auxiliary hole is also made to pass through the mounting hole on the hole wall of the mounting hole.

The beneficial effect of the present invention is that, by designing the wheel body of the overmolded bearing to have a structure with a first plastic body and a second plastic body, the first plastic body and the second plastic body can be injection-molded twice, so that the first plastic body and the second plastic body can be injected twice. When the first plastic body is injection molded, the amount of glue is small, which can effectively avoid excessive shrinkage of the mounting hole (excessive extrusion of the bearing) during the cooling process of the first plastic body. Further, when the first plastic body is individually injection-molded, the first plastic body can be injection-molded into a denser structure, thereby improving the hardness, impact resistance and friction resistance of the plastic-coated bearing wheel body. The second plastic body is designed to cover the outside of the first plastic body, so that the bearing, the first plastic body and the second plastic body form a plastic-covered bearing with a stable structure.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is a schematic diagram of the three-dimensional structure of the plastic-coated bearing according to the first embodiment of the present invention;

2 is a schematic diagram of an explosion structure of a plastic-coated bearing according to Embodiment 1 of the present invention;

3 is a schematic three-dimensional structure diagram of a first plastic body according to Embodiment 1 of the present invention;

4 is a schematic cross-sectional structural diagram of a first plastic body according to Embodiment 1 of the present invention;

5 is a schematic diagram of the three-dimensional structure of a second plastic body according to Embodiment 1 of the present invention;

6 is a schematic cross-sectional structure diagram of a second plastic body according to Embodiment 1 of the present invention;

FIG. 7 is a schematic cross-sectional structural diagram of the plastic-coated bearing according to the first embodiment of the present invention.

Detailed ways

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

Example 1

As shown in FIGS. 1 and 2 , the overmolded bearing of this embodiment includes a bearing 1 and a wheel body 2 disposed outside the bearing 1 , and the wheel body 2 includes a first plastic body 21 and a second plastic body 22 . A mounting hole 211 is formed on the first plastic body 21 , and the bearing 1 is fixed in the mounting hole 211 ; the second plastic body 22 is wrapped around the first plastic body 21 . By designing the wheel body 2 with the overmolded bearing to have the structure of the first plastic body 21 and the second plastic body 22, the first plastic body 21 and the second plastic body 22 can be injected in two times, so that the first injection molding A plastic body 21 has a small amount of glue, which can effectively avoid excessive shrinkage (shrinkage) of the first plastic body 21 during the cooling process, resulting in excessive shrinkage of the mounting hole 211 (excessive extrusion of the bearing 1 ). Further, when the first plastic body 21 is individually injection-molded, the first plastic body 21 can be injection-molded into a denser structure, thereby improving the hardness, impact resistance and friction resistance of the overmolded bearing wheel body 2 . The second plastic body 22 is designed to cover the outside of the first plastic body 21 , so that the bearing 1 , the first plastic body 21 and the second plastic body 22 form a plastic-covered bearing with a stable structure. The plastic-covered bearing with the above structure can not only improve the hardness, impact resistance and friction resistance of the plastic-covered bearing wheel body 2 through the first plastic body 21 , but also can change the existing integral outer plastic layer to the first plastic layer. The plastic body 21 and the second plastic body 22 are two plastic bodies, thereby reducing the glue amount of the first plastic body 21 and preventing the bearing 1 from being locked or stuck due to excessive shrinkage of the first plastic body 21 .

As shown in FIG. 2 , the first plastic body 21 is further formed with one or more auxiliary holes 212 , and the auxiliary holes 212 pass through the first plastic body 21 ; the second plastic body 22 includes filling the The filling part 221 of the auxiliary hole 212 and the covering part 222 covering the first plastic body 21 . The provision of the auxiliary holes 212 can further reduce the glue amount of the first plastic body 21 on the one hand, and can be used as a glue flow channel when the second plastic body 22 is injected on the other hand. After the second plastic body 22 is formed, its filling part 221 is fitted into the auxiliary hole 212 , and both ends of the filling part 221 are respectively connected to the covering parts 222 covering the first plastic body 21 , so that the bearing 1 , the first plastic body 21 and the second plastic body 22 form a plastic-coated bearing with a stable structure. Further, the auxiliary hole 212 passes through the mounting hole 211 on the hole wall of the mounting hole 211 . Preferably, the auxiliary hole 212 completely penetrates the hole wall of the installation hole 211 in the axial direction, so that the hole wall of the installation hole 211 forms a broken section of hole wall or multiple sections of hole walls spaced apart from each other (in FIG. 2 , Three sections). Since the first plastic body 21 has the mounting hole 211 and one or more auxiliary holes 212 on the hole wall of the mounting hole 211 penetrating the mounting hole 211, the mounting hole 211 has a certain elastic expansion and contraction performance , so that the bearing 1 can be fixed in the mounting hole 211 after the first plastic body 21 is formed, so as to avoid the situation that the bearing 1 is stuck or locked when the first plastic body 21 cools and shrinks.

As shown in FIGS. 3-7 , a convex ring 213 is provided in the middle of the outer side of the first plastic body 21 , and an annular track groove 223 is provided on the outer side of the second plastic body 22 , and the convex ring 213 is located in the annular track groove 223 bottom. Between the outer surface of the first plastic body 21 and the second plastic body 22 , a concave and convex anti-drop structure 23 is provided. The disengagement prevention structure 23 can make the combination of the first plastic body 21 and the second plastic body 22 more stable, and prevent cracking or separation between the second plastic body 22 and the first plastic body 21 when the overmolded bearing runs on the track. Preferably, the anti-detachment structure 23 includes an annular groove 231 disposed on the outer surface of the first plastic body 21 and symmetrically disposed with respect to the convex ring 213, and an annular groove 231 disposed on the second plastic body 22 and clamped An annular snap ring 232 is provided in the annular groove 231 . The annular grooves 231 are symmetrically arranged on both sides of the convex ring 213, so that when the overmolded bearing runs on the track, the track will keep pressing the annular snap ring 232 on the second plastic body 22 against the annular groove 231 Inside, cracking or separation between the second plastic body 22 and the first plastic body 21 is further prevented. It should be noted that the protruding ring 213 located at the bottom of the annular track groove 223 includes the case where the protruding ring 213 is exposed to the annular track groove 223, and also includes the case where the protruding ring 213 is not exposed (that is, the groove wall of the annular track groove 223 is not exposed). formed entirely from the second plastic body 22). In the case that the convex ring 213 is exposed on the annular track groove 223, it can abut the track when the overmolded bearing runs on the track, and with the excellent hardness of the first plastic body 21, the performance of impact resistance and friction resistance can undertake most of the The force of the orbit. Under the condition that the convex ring 213 is not exposed on the annular track groove 223 (not shown in the figure), when the overmolded bearing runs on the track, the annular track groove 223 receives the force from the track and passes through the bottom wall of the annular track groove 223. It is transmitted to the convex ring 213, and the convex ring 213 (the first plastic body 21) at this time can play the role of an internal support frame.

As shown in FIGS. 3-7 , a plurality of bosses 214 are formed at the end of the first plastic body 21 , and the second plastic body 22 also fills the area between the plurality of bosses 214 . The end surfaces of the bosses 214 are flush with the surface of the second plastic body 22 filling the areas between the bosses 214 . Specifically, the cladding portion 222 partially fills the area between the plurality of bosses 214 , and the cladding portion 222 is formed on the holes 224 corresponding to the bosses 214 . The arrangement of the plurality of bosses 214 forms grooves between adjacent bosses 214 , thereby reducing the amount of glue for injection molding the first plastic body 21 and further preventing excessive shrinkage of the first plastic body 21 when cooling. In addition, the arrangement of the bosses 214 can also enable the covering portion of the second plastic body 22 to be partially filled into the grooves formed between the adjacent bosses 214 when the second plastic body 22 is injected, so that the second plastic body 22 can be partially filled. 22 is more closely combined with the first plastic body 21 .

Embodiment 2

The present embodiment provides a method for producing the plastic-coated bearing of Embodiment 1, comprising the following steps:

S1 injects the first plastic body 21 to form a mounting hole 211 on the first plastic body 21 ; S2 fixes the bearing 1 into the mounting hole 211 ; S3 injects the second plastic body 22 to form the second plastic body 211 22 wraps the first plastic body 21 . Divide the injection into two times, so that the first plastic body 21 is injected with a small amount of glue, which can effectively avoid excessive shrinkage (shrinkage) of the first plastic body 21 during the cooling process. 1). Further, when the first plastic body 21 is individually injection-molded, the first plastic body 21 can be injection-molded into a denser structure, thereby improving the hardness, impact resistance and friction resistance of the overmolded bearing wheel body 2 . The second plastic body 22 is designed to cover the outside of the first plastic body 21 , so that the bearing 1 , the first plastic body 21 and the second plastic body 22 form a plastic-covered bearing with a stable structure. Further, when the first plastic body 21 is injection molded, one or more auxiliary holes 212 are also formed on the first plastic body 21, and the auxiliary holes 212 penetrate the first plastic body 21; injection molding When the second plastic body 22 is used, the second plastic body 22 is also filled with the one or more auxiliary holes 212 . Preferably, when the first plastic body 21 is injection-molded, the auxiliary hole 212 is also made to pass through the mounting hole 211 on the hole wall of the mounting hole 211 . Forming one or more auxiliary holes 212 on the first plastic body 21 can further reduce the glue amount of the first plastic body 21 on the one hand, and can be used as a glue flow channel when the second plastic body 22 is injected. The one or more auxiliary holes 212 are filled with the second plastic body 22 , so that the bearing 1 , the first plastic body 21 and the second plastic body 22 form a structurally stable and strong overmolded bearing. Further, since the first plastic body 21 has a mounting hole 211 and one or more auxiliary holes 212 on the hole wall of the mounting hole 211 that pass through the mounting hole 211 , the mounting hole 211 has a certain elastic expansion Therefore, the bearing 1 can be fixed in the mounting hole 211 after the first plastic body 21 is formed, so as to avoid the situation that the bearing 1 is stuck or locked when the first plastic body 21 cools and shrinks.

It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them. For those skilled in the art, the technical solutions recorded in the above embodiments can be modified, or some of the technical features can be modified. Equivalent replacements are made; and all such modifications and replacements shall fall within the protection scope of the appended claims of the present invention.

Claims (13)

1. A plastic-coated bearing, comprising a bearing and a wheel body arranged outside the bearing, wherein the wheel body comprises: a first plastic body, a mounting hole is formed on the first plastic body, and the bearing is fixed in the mounting hole; A second plastic body, the second plastic body is wrapped outside the first plastic body. 2 . The overmolded bearing according to claim 1 , wherein one or more auxiliary holes are further formed on the first plastic body, and the auxiliary holes pass through the first plastic body; The plastic body includes a filling part for filling the auxiliary hole and an outer covering part covering the first plastic body. 3 . The plastic-coated bearing according to claim 2 , wherein the auxiliary hole penetrates through the mounting hole on the hole wall of the mounting hole. 4 . 4. The plastic-coated bearing according to claim 3, wherein the auxiliary hole completely penetrates the hole wall of the installation hole in the axial direction, so that the hole wall of the installation hole forms a broken section of the hole wall or A plurality of segments of hole walls spaced apart from each other. 5 . The overmolded bearing according to claim 2 , wherein a convex ring is provided in the middle of the outer side surface of the first plastic body, an annular track groove is provided on the outer side of the second plastic body, and the convex ring is located in the Bottom of the annular track groove. 6. The plastic-coated bearing according to any one of claims 2-5, wherein a concave-convex anti-separation structure is provided between the outer side surface of the first plastic body and the coating portion. 7 . The overmolded bearing according to claim 6 , wherein the anti-detachment structure comprises an annular groove disposed on the outer side surface of the first plastic and symmetrically disposed with respect to the annular protrusion, and an annular groove disposed on the outer surface of the first plastic. 8 . An annular snap ring on the cladding portion and clamped in the annular snap groove. 8 . The overmolded bearing according to claim 2 , wherein a plurality of bosses are formed on the end surface of the first plastic body, and the covering portion also fills the space between the plurality of bosses. 9 . area. 9 . The overmolded bearing according to claim 8 , wherein the end surface of the boss is flush with the outer surface of the cladding portion filling the area between the bosses. 10 . 10. The overmolded bearing according to any one of claims 2 to 5, wherein the first plastic body and the second plastic body are made of the same plastic, and the density of the first plastic body is greater than that of all plastic bodies. the density of the second plastic body. 11. A manufacturing method of a plastic-coated bearing, characterized in that, comprising the following steps: injecting a first plastic body to form a mounting hole on the first plastic body; Fix the bearing into the mounting hole; A second plastic body is injection molded so that the second plastic body covers the first plastic body. 12 . The manufacturing method of the overmolded bearing according to claim 11 , wherein when the first plastic body is injection-molded, one or more auxiliary holes are further formed on the first plastic body, and the The auxiliary holes penetrate through the first plastic body; when the second plastic body is injection-molded, the second plastic body is also filled with the one or more auxiliary holes. 13 . The method for manufacturing a plastic-coated bearing according to claim 12 , wherein when the first plastic body is injection-molded, the auxiliary hole is also made to pass through the mounting hole on the hole wall of the mounting hole. 14 . .

Images