JP6938015B2 - Caster and mobile - Google Patents

Description

The present invention relates to casters attached to moving bodies such as trolleys, furniture, and carry bags, and moving bodies to which casters are attached.

In a moving body such as a trolley, furniture, or a carry bag, a wheel support device called a caster is attached to the lower part of the moving body in order to move the moving body. This caster is composed of a wheel and a frame that rotatably supports the wheel, a swivel device that swivels the frame, and the like. Thrust bearings are used so that
The thrust bearing used for this caster has a structure in which a large number of balls are held between the upper substrate and the lower substrate with or without a cage, and the upper substrate and the lower substrate are held. The side substrate and the ball are often made of metal, which has mechanical strength and is inexpensive.
In a caster using a thrust bearing composed of a metal upper substrate, a lower substrate and a ball, it is necessary to inject a lubricant such as grease into the thrust bearing in order to smoothly turn the frame supporting the wheel. ..
By the way, moving objects such as trolleys equipped with casters are used in various environments, and in the case of moving objects such as trolleys used in an environment exposed to water such as underwater or in an environment where they are frequently washed, the casters are used. There is a problem that the lubricant injected into the thrust bearing runs out in a short time and the casters do not turn.
Therefore, various casters using thrust bearings that can be used for a long time even in an environment exposed to water have been proposed.
For example, Japanese Patent Application Laid-Open No. 10-181302 (Patent Document 1) states that a swivel shaft is supported by a two-stage thrust bearing, and the thrust bearing is reinforced with a fiber material. A swivel shaft support device has been proposed in which a (ball) and a resin cage are used to prevent rusting and load bias and maintain smooth movement of the swivel shaft for a long period of time.
Further, Japanese Patent Application Laid-Open No. 2000-85308 (Patent Document 2) describes a fixing portion fixed to a carrier such as a trolley, and a shaft inserted into a shaft insertion hole formed in communication with the fixing portion. In a caster swivel device including a wheel support portion supported by this shaft and swivel via a bearing ball, a caster having an annular seal sandwiched in a part of a gap formed between the fixed portion and the wheel support portion. A swivel device has been proposed.

However, in the thrust bearing of the swivel shaft support device of Patent Document 1, since a cage made of resin is used, the rotating bodies (balls) do not roll and come into contact with each other, the rotational resistance increases, and the bearing is held. Compared to those that do not use a vessel, the number of balls is small, the load applied to one ball becomes large, it becomes difficult to roll, and there arises a problem that the turning performance deteriorates.
Next, in the caster swivel device of Patent Document 2, the fixed portion and the wheel support portion are formed of metal, plastic, or the like, and a bearing ball made of an alloy such as stainless steel, ceramics, or the like is housed between them, and the fixed portion and the wheel support are supported. An annular seal is sandwiched in a part of the gap formed between the portions, but the gap cannot be completely sealed, and in particular, a moving body such as a trolley is washed with a detergent or the like. In this case, the grease filled in the gap is washed away by the cleaning liquid, and there arises a problem that the lubricant must be replenished every time the cleaning is performed.
By the way, ceramic balls are used for the thrust bearings of Patent Document 1 and Patent Document 2, but the ceramic balls are extremely expensive and are generally casters of moving objects such as trolleys, which are required to have a low price. Cannot be used for thrust bearings.
In this regard, Patent Document 1 describes that stainless steel or bearing steel is used in addition to ceramic as the material of the rotating body (ball), and Patent Document 2 also describes that stainless steel or the like is used as the material of the bearing ball in addition to ceramic. It is stated that an alloy is used.
However, in a thrust bearing without a cage, when metal balls such as stainless steel or steel are used, the rolling resistance (rolling friction coefficient) between the metal balls is large, so that the metal balls come into contact with each other. However, in order to roll smoothly, a lubricant is indispensable, and in the caster of a trolley that is frequently washed with detergent etc., the lubricant is washed away every time it is washed, and it is necessary to replenish the lubricant. Therefore, there is a problem that a great deal of labor is required.
In this case, it is conceivable to use a resin ball that has a smaller rolling resistance (rolling friction coefficient) than a metal ball and rolls while contacting without a lubricant. Compared with this, the hardness and compressive strength are inferior, and the resin balls are crushed and deformed by the weight of a moving body such as a trolley, the resin balls do not roll smoothly, and the turning performance of the casters deteriorates.

Japanese Unexamined Patent Publication No. 10-181302 Japanese Unexamined Patent Publication No. 2000-85308

The problem to be solved by the present invention is to rotate a wheel, and lubricates a caster provided with a thrust bearing that stores a large number of rolling elements such as balls and rotates while the rolling elements are in contact with each other. The thrust bearing rotates smoothly without using a chemical, the rotation of the thrust bearing is not impaired by the weight of the moving body, it is inexpensive and durable, and the turning performance does not deteriorate even after long-term use. Is to do.

The invention according to claim 1 is a caster provided with a wheel, a support frame for rotatably supporting the wheel, a swivel shaft, and a thrust bearing attached to the swivel shaft to swivel the support frame. The thrust bearing includes a large number of rolling elements held between the upper substrate, the lower substrate, and the upper substrate and the lower substrate without a cage, and the large number of rolling elements are made of metal. consists manufactured of rolling elements and a resin of rolling elements, the plurality of rolling elements, the ball grooves of the upper substrate without substantially clearance ball grooves of the lower substrate, contacting the rolling elements with adjacent without lubricant The metal rolling element and the resin are arranged so as to roll on the ball groove surface of the upper substrate and the ball groove surface of the lower substrate , and the metal rolling elements are not adjacent to each other. The above-mentioned problem is solved by providing a caster on which a rolling element made of a product is arranged.

The invention according to claim 2 solves the above-mentioned problems by providing casters in which the metal rolling elements and the resin rolling elements are alternately arranged.

The invention according to claim 3 solves the above-mentioned problem by providing a caster in which the rolling element is a ball or a roller.

The invention according to claim 4 solves the above-mentioned problems by providing casters in which one of the upper substrate and the lower substrate is made of metal and the other is made of resin.

The invention according to claim 5 solves the above-mentioned problem by providing a moving body provided with the casters.

The invention according to claim 6 solves the above-mentioned problems by providing a moving body which is a trolley.

In the caster of the invention according to claim 1, the metal rolling element of the thrust bearing always makes rolling contact with the resin rolling element, and the rolling resistance (rolling resistance) (as compared with the case where the metal rolling elements make rolling contact with each other). The rolling friction coefficient) is small, the thrust bearing rotates smoothly without using a lubricant, the load applied to the casters is supported mainly by the metal rolling element, and the resin rolling element is deformed to form the thrust bearing. It prevents the rotation from being impaired, is inexpensive and durable, and has the effect of not deteriorating the turning performance even after long-term use.

In the caster of the invention according to claim 2, the proportion of the metal rolling element can be further increased, and the resin rolling element can be further prevented from being deformed to impair the rotation of the thrust bearing. It plays the effect.

The caster of the invention according to claim 3 has the same effect as the caster of claim 1.

In the caster of the invention according to claim 4, further, as compared with the case where both the upper substrate and the lower substrate are made of metal or resin, the rolling element is not difficult to roll, and the thrust bearing It has the effect of making the rotation smoother.

The mobile caster of the invention according to claim 5 has the same effect as the caster of claims 1 to 4.

The caster of the trolley, which is the moving body of the invention according to claim 6, has the same effect as the caster of claims 1 to 4.

It is a front view of the caster of this invention. It is a left side view of the caster shown in FIG. It is a top view of the caster shown in FIG. FIG. 2 is a cross-sectional view taken along the line YY of FIG. It is a front view of the thrust bear rig 20 shown in FIG. 1 with a part of the ball 23 omitted. It is a vertical sectional view of the thrust bear rig 20 shown in FIG. 1 in which the ball 23 is omitted. It is a top view of the thrust bear rig 20 shown in FIG. 1 with the upper substrate 21 removed. It is a top view of the thrust bear rig 20 in which the ratio of the resin ball 23p is increased, and the upper substrate 21 is removed. It is a front view of the thrust bear rig which used a roller for a rolling element, and a part of the roller is omitted. It is a vertical cross-sectional view of the thrust bear rig shown in FIG. 9 in which the rollers are omitted. It is a top view of the thing which removed the upper substrate from the thrust bear rig shown in FIG. It is a front view of the dolly to which the caster 1 is attached. It is a left side view of the dolly shown in FIG. It is a top view of the dolly shown in FIG.

[caster]
An embodiment of the caster of the present invention will be described.
1 is a front view of the caster of the present invention, FIG. 2 is a left side view of the caster shown in FIG. 1, FIG. 3 is a plan view of the caster shown in FIG. 1, and FIG. 4 is a YY cross section of FIG. It is a figure.
In the figure, 1 is a caster, 10 is a wheel, 11 is an axle, 12 is a support frame, 13 is a swivel shaft, 13a is a head, 13b is a caulking part, 14 is a mounting plate, 14a is a recess, 14b is a long hole, 20 Is a thrust bearing, 21 is an upper substrate, 22 is a lower substrate, and 23 is a ball serving as a rolling element.
As shown in the figure, the caster 1 is composed of wheels 10, axles 11, support frames 12, swivel shafts 13, mounting plates 14, and the like.
Then, both ends of the axle 11 into which the wheels 10 are inserted are attached to the side surface portions of the support frame 12, whereby the wheels 10 are rotatably supported by the support frame 12.
Further, as shown in FIG. 4, a hole provided in the upper surface portion of the support frame 12, a shaft hole of the thrust bear rig 20 composed of the upper substrate 21, the lower substrate 22 and the ball 23, and a recess of the mounting plate 14 A swivel shaft 13 is inserted into the hole provided in the central portion of 14a, whereby the support frame 12 and the mounting plate 14 are connected via the thrust bear rig 20, and the support frame 12 swivels with respect to the mounting plate 14. It is free.
In this case, the head portion 13a of the swivel shaft 13 presses the peripheral portion of the hole of the recess 14a, and the caulking portion 13b of the swivel shaft 13 presses the periphery of the hole provided on the upper surface portion of the support frame 12.
Further, screw portions of bolts are inserted into the elongated holes 14a provided at the four corners of the mounting plate 14, and the mounting plate 14 is attached to the bottom of a moving body such as a trolley by a nut screwed into the screw portions.

[Thrust Bear Rig]
Next, the thrust bear rig 20 used for the caster 1 will be described.
FIG. 5 is a front view of the thrust bear rig 20 shown in FIG. 1 with a part of the ball 23 omitted, and FIG. 6 is a vertical sectional view of the thrust bear rig 20 shown in FIG. 1 with the ball 23 omitted. FIG. Is a plan view of the thrust bear rig 20 shown in FIG. 1 with the upper substrate 21 removed.
In the figure, 21a and 22a are shaft holes, 21b and 22b are ball grooves, 21c and 22c are ball groove surfaces, 23s are metal balls, and 23p are resin balls.
As shown in FIGS. 5 and 6, in the upper substrate 21, a shaft hole 21a is provided in the central portion, and a ball groove 21b having a semicircular cross section and an annular shape is provided between the shaft hole 21a and the outer peripheral surface. Similarly, the lower substrate 22 is also provided with a shaft hole 22a and a ball groove 22b.
A large number of balls 23 are arranged in the ball grooves 21b and 22b of the upper substrate 21 and the lower substrate 22, and the adjacent balls 23 roll on the ball groove surfaces 21c and 22c while contacting each other. ..
The upper substrate 21 and the lower substrate 22 are made of an alloy such as stainless steel or a metal such as steel, or a phenol resin having high hardness and compressive strength and excellent wear resistance and chemical resistance, PTFE (poly). Resins such as tetrafluoroethylene tetrafluoroethylene resin), UHMW (ultra high molecular weight polyethylene), PP (polypropylene), PEEK (polyether ether ketone), PPS (polyphenylene sulfide), PCTFE (polychlorotrifluoroethylene), carbon, etc. Made of is used.
In this case, if both the upper substrate 21 and the lower substrate 22 are made of metal, they are excellent in terms of hardness, compressive strength, abrasion resistance, chemical resistance, etc. of the substrate itself, but as will be described later, balls. Since a metal ball is used as a part of the 23, the rolling resistance (rolling friction coefficient) between the metal ball 23 and the upper substrate 21 and the lower substrate 22 becomes large, and the rotation of the thrust bearing 20 becomes poor. Wear also increases.
Further, if both the upper substrate 21 and the lower substrate 22 are made of resin, the portion of the upper substrate 21 and the lower substrate 22 that hits the ball 23 is dented due to the load of a moving body such as a trolley to which the caster 1 is attached. , The ball 23 becomes difficult to roll, and the rotation of the thrust bearing 20 becomes poor.
Therefore, it is desirable that one of the upper substrate 21 and the lower substrate 22 is made of metal and the other is made of resin so that the rotation of the thrust bearing 20 does not deteriorate.

As shown in FIG. 7, the ball 23 is composed of a metal ball 23s and a resin ball 23p.
For the metal balls 23s, metal balls made of an alloy such as stainless steel or steel are used.
The resin ball 23p contains Duracon (POM: polyoxymethylene), 66 nylon, PE (polyethylene), PP, polystyrene, polycardate, and Teflon (registered), which have high hardness and compressive strength and excellent wear resistance and chemical resistance. Resin balls made of (trademark), acrylic, vinyl chloride, ABS, etc. are used.
As described above, the balls 23 are arranged in the ball grooves 21c and 22c with almost no gap, and the balls 23 roll on the ball groove surfaces 21c and 22c while the adjacent balls 23 are in contact with each other.
In FIG. 7, the ball represented by light ink is a metal ball 23s, the ball represented by a net dot is a resin ball 23p, and the metal ball 23s and the resin ball 23p are arranged so that the metal balls 23s do not come into contact with each other adjacent to each other. The metal balls 23s and the resin balls 23p are arranged alternately, and eight each of the metal balls 23s and the resin balls 23p are arranged, for a total of 16 pieces.
By assuming that the balls 23 are a mixture of the metal balls 23s and the resin balls 23p and preventing the metal balls 23s from adjoining each other in contact with each other, the following effects (1) to (3) can be obtained. be.
(1) The metal balls 23s always make rolling contact with the resin balls 23p, and the rolling resistance (rolling friction coefficient) is smaller than the case where the metal balls 23s make rolling contact with each other, and the thrust bearing 20 rotates smoothly without a lubricant. Can be made to.
(2) Mainly the metal balls 23s support the load of the moving body to which the casters are attached, the load applied to the resin balls 23p is reduced to reduce the deformation, and the resin balls 23p are greatly deformed to rotate the thrust bearing 20. Can be prevented from getting worse.
(3) Even if a metal material is used for the upper substrate 21 or the lower substrate 22, the number of metal balls 23s in contact with the upper substrate 21 or the lower substrate 22 is set to be less than half of the entire balls 23, and the balls 23 as a whole. It is possible to prevent the rolling resistance of the upper substrate 21 or the lower substrate 22 from increasing, and prevent the rotation of the thrust bearing 20 from becoming worse.
In this case, in terms of the effects of the above (1) and (2), as many metal balls 23s as possible are arranged without adjoining the metal balls 23s, that is, the metal balls 23s and the resin are arranged as shown in FIG. It is desirable to arrange the balls 23p alternately so that the ratio of the metal balls 23s and the resin balls 23p is the same. However, if the load applied to the thrust bearing 20 is not so large, increase the ratio of the resin balls 23p to make the balls. The rolling resistance of the entire 23 may be reduced so that the thrust bearing 20 can be rotated more smoothly.
FIG. 8 is a plan view of the thrust bear rig 20 in which the proportion of the resin balls 23p is increased and the upper substrate 21 is removed. In FIG. 8, five metal balls 23s and ten resin balls 23p are arranged with every two balls 23 as metal balls 23s.

In the above-described embodiment of the caster of the present invention, a ball is used as the rolling element of the thrust bearing, but a thrust bearing using a roller as a rolling element may be used instead of the ball.
9 is a front view of a thrust bear rig using a roller as a rolling element with a part of the roller omitted, FIG. 10 is a vertical sectional view of the thrust bear rig shown in FIG. 9 with the roller omitted, and FIG. 11 is a vertical sectional view. , FIG. 9 is a plan view of the thrust bear rig shown in FIG. 9 with the upper substrate removed.
In the figure, 30 is a thrust bearing, 31 is an upper substrate, 32 is a lower substrate, 33 is a roller serving as a rolling element, 31a and 32a are shaft holes, 31b and 32b are roller grooves, and 31c and 32c are roller groove surfaces. 33s is a metal roller and 33p is a resin roller.
As shown in FIGS. 9 and 10, in the upper substrate 31 of the thrust bearing 30, a shaft hole 31a is provided in the central portion, and a roller groove 31b having a trapezoidal cross section and an annular shape is provided between the shaft hole 31a and the outer peripheral surface. Is provided, and the lower substrate 32 is also provided with a shaft hole 32a and a roller groove 32b in the same manner.
A large number of truncated cone-shaped rollers 33 are arranged in the roller grooves 31b and 32b of the upper substrate 31 and the lower substrate 32 so that the adjacent rollers 23 roll on the roller groove surfaces 31c and 32c while contacting each other. It has become.
As the upper substrate 31 and the lower substrate 32, those made of metal similar to those of the upper substrate 21 and the lower substrate 22 of the thrust bearing 20 shown in FIGS. 5 to 8 or those made of resin are used.
As shown in FIG. 11, the roller 33 includes a metal roller 33s and a resin roller 33p.
The metal roller 33s uses the same metal roller as the metal ball 23s, and the resin roller 33p uses the same resin roller as the resin ball 23p.
As described above, the rollers 33 are arranged in the roller grooves 31c and 32c with almost no gap, and roll on the roller groove surfaces 31c and 32c while the adjacent rollers 33 are in contact with each other.
In FIG. 11, the roller represented by light ink is a metal roller 33s, the roller represented by a mesh dot is a resin roller 33p, and the metal roller 33s and the resin roller 33p are arranged so that the metal rollers 33s do not come into contact with each other adjacent to each other. The metal rollers 33s and the resin rollers 33p are arranged alternately, and a total of 16 metal rollers 33s and 8 resin rollers 33p are arranged.
Since the roller 33 of the thrust bearing 30 is less deformed by a load than the ball 23 of the thrust bearing 20, when the weight of the moving body is large and the load applied to the thrust bearing of the caster is large, the roller 33 is rolled. It is desirable to use the thrust bearing 30 described above.

[Mobile]
Next, a moving body such as a trolley to which the caster 1 is attached will be described.
12 is a front view of the dolly to which the caster 1 is attached, FIG. 13 is a left side view of the dolly shown in FIG. 12, and FIG. 13 is a plan view of the dolly shown in FIG.
In the figure, 40 is a dolly, 41 is a loading platform, 41a is a bottom plate of the loading platform 41, and 42 is a bolt, and the same objects have the same reference numerals.
As shown in the figure, the trolley 40 includes a loading platform 41 and casters 1 attached to the four corners of the bottom plate 41a of the loading platform 41.
The loading platform 41 has a shallow box shape with an open upper surface, and can be loaded with, for example, a food container containing food.
Bolt holes are provided at the four corners of the bottom plate 41a of the loading platform 41 at positions corresponding to the elongated holes 14a of the mounting plate 14 of the caster 1, and the bolts 42 are passed through the bolt holes and the elongated holes 14a to pass nuts (not shown). ) Is screwed into the threaded portion of the bolt 42 and tightened, so that the mounting plate 14 of the caster 1 is attached to the bottom plate 41a of the loading platform 41.
The trolley 40 is used for transporting heavy objects such as food containers containing food at convenience stores and the like, and since food and the like spill and become dirty during transportation, the trolley 40 is frequently washed with detergent.
In this case, since the caster 1 using the thrust bearing 20 in which the metal balls 23s and the resin balls 23p are mixed is attached to the carriage 40, the thrust bearing 20 rotates smoothly without the lubricant and the wheels 10 are moved. Eliminates the need to inject lubricant after every swivel and wash.
Further, even when a heavy object such as a food container is transported by the trolley 40, the metal balls 23s of the thrust bearing 20 mainly support the load applied to the thrust bearing 20, so that the resin balls 23p are deformed and the thrust bearing 20 is deformed. It is prevented that the rotation becomes poor and the wheel 10 becomes difficult to turn.
In addition to the trolley as described above, the moving body of the present invention includes furniture such as tables, chairs and desks, OA equipment, carry bags and the like.

The casters of the present invention are inexpensive, durable, and can be used for a long period of time without using a lubricant so that the thrust bearing rotates smoothly and the rotation of the thrust bearing is not impaired by the weight of the moving body. However, the turning performance does not deteriorate, and it can be used for moving objects such as trolleys, furniture, and carry bags.

1 Caster 10 Wheel 11 Axle 12 Support frame 13 Swivel shaft 13a Head 13b Caulking part 14 Mounting plate 14a Recess 14b Long hole 20 Thrust bearing 21 Upper substrate 21a Shaft hole 21b Ball groove 21c Ball groove surface 22 Lower substrate 22a Shaft hole 22b Ball groove 22c Ball groove surface 23 Ball 23s Metal ball 23p Resin ball 30 Thrust bearing 31 Upper substrate 31a Shaft hole 31b Roller groove 31c Roller groove surface 32 Lower substrate 32a Shaft hole 32b Roller groove 32c Roller groove surface 33 Roller 33s Metal roller 33p Resin roller 40 trolley 41 loading platform 41a bottom plate 42 bolt

Claims (6)

A caster including a wheel, a support frame that rotatably supports the wheel, a swivel shaft, and a thrust bearing that is attached to the swivel shaft to rotatably support the support frame.
The thrust bearing comprises a number of rolling elements held between the upper substrate, the lower substrate, and the upper substrate and the lower substrate without a cage.
The large number of rolling elements are composed of a metal rolling element and a resin rolling element.
The large number of rolling elements have almost no gap between the ball groove of the upper substrate and the ball groove of the lower substrate, and the adjacent rolling elements are in contact with each other without a lubricant on the ball groove surface of the upper substrate and below the ball groove surface. The metal rolling element and the resin rolling element are arranged so as to roll on the ball groove surface of the side substrate and the metal rolling elements are not adjacent to each other. Caster to do. The caster according to claim 1, wherein the metal rolling elements and the resin rolling elements are alternately arranged. The caster according to claim 1 or 2, wherein the rolling element is a ball or a roller. The caster according to any one of claims 1 to 3, wherein one of the upper substrate and the lower substrate is made of metal and the other is made of resin. A mobile body including the caster according to any one of claims 1 to 4. The moving body according to claim 5, wherein the moving body is a trolley.

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