JP2010112499A - Sliding bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide swing bearings to be used in construction and agricultural machinery operated mainly outdoors, which is manufactured comparatively inexpensively and in a short delivery time. <P>SOLUTION: The sliding bearing is formed of an inner ring 3 and an outer ring 2 which have coaxially a rotation-axis. Either one of the inner ring 3 and the outer ring 2 holds the other ring in itself to carry out a coaxial sliding rotation. Thus, the sliding bearing has a structure catching an external force such as moment as a bearing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a bearing used in a construction machine, an agricultural machine, a crane, and other general machines in terms of application fields.
In terms of load, it relates to bearings that receive radial load, thrust load in both directions, and moment load.
It is also a category of slewing bearings and moment bearings.
It also relates to a bearing with a brake that maintains the turning stop state.

Conventionally, rolling bearings such as 4-point contact type bearings and cross roller bearings via rolling elements are known as bearings that receive radial load, thrust load in both directions, and moment load.
There is also a bearing with a brake that holds the turning stop state invented by the present applicant. (See Patent Document 1)
Patent application title: Bearing having rotation stopping means

Prior to describing the problems to be solved by the invention, a brief description of conventional bearings is provided.
As shown in FIG. 1, a conventional bearing 1 is composed of three main elements: an outer ring 2, an inner ring 3, and a rolling element 4.
The rolling element 4 rolls on a track 5 formed by the outer ring 2 and the inner ring 3. The rolling element 4 is an indispensable presence that connects the outer ring 2 and the inner ring 3, and it can freely rotate the outer ring 2 and the inner ring 3 and also accept various external forces from the inner and outer rings. Have an important role.
In this example, the rolling element 4 uses a ball, but may be a roller.
Although the cage of the rolling element 4 is not shown, it may or may not be present.
It has a bolt hole 6 for mounting the bearing, a seal 7 and a gear 8.

The problem with conventional bearings is that manufacturing costs are high and delivery times are very long. Details are described below.
The fundamental reason for the high manufacturing cost is the existence of the orbit itself, which is the reason for its existence. This is because the track has a very simple shape, but it takes many steps to create.
Although the rolling element rolls on a track formed by the inner and outer rings, since the rolling element and the track are in point contact or line contact, considerable surface pressure is applied. Therefore, in order to obtain a material strength that can accept it, a quenching process is essential for the rolling elements and the raceways.
In addition, since the rolling element literally rolls on the track and requires a work accuracy of μ order, the grinding process after quenching is an essential process.
As described above, the creation of the track requires a quenching and grinding process after a general machining process, resulting in a very high cost.
Furthermore, since the quenching process and grinding process are specialized processes, they are often outsourced to specialized manufacturers outside the company, further increasing costs.
The reason for the long delivery time is that the delivery time management becomes difficult by performing the quenching process and the grinding process outside the company. For this reason, delivery times can take anywhere from six months to a year, losing business opportunities.
And finally there is such a problem that is not visible.
The problem is excessive quality of rotational accuracy.
A turning device for a large machine such as a construction machine, an agricultural machine, or a crane often does not require a μ-order rotation accuracy unlike a machine tool. In other words, since a large object is swiveled, a rotational accuracy of the order of 0.1 to 1 mm is often sufficient.
Rolling bearings do not rotate smoothly if there are no rolling elements on the concentric circle of the rotating shaft. Therefore, the rolling accuracy must be on the order of μ. However, from the viewpoint of the rotational accuracy required by the outdoor machinery and equipment in which it is incorporated In most cases, the quality is excessive.

The present inventors have invented a brake bearing with a built-in brake shown in FIGS. 2 to 3, and this bearing also has the same problem due to the track.
Briefly describing the brake bearing, the outer ring 2 and the inner ring 3 can freely rotate via the rolling elements 4, while the ring-shaped piston 9 installed in the outer ring moves in parallel with the rotation axis to move the inner ring 3 A powerful braking action can be obtained by surface-welding the surface.
In addition, this brake bearing is epoch-making in that a powerful brake is built into the bearing, but if you want to obtain a super strong braking force, you need to have multiple brake plates 10 as shown in Fig. 4, The cost was even higher.

In order to solve the above-described problems of the conventional bearing, a bearing having no raceway, that is, a rolling element, in other words, a bearing in which the inner ring and the outer ring are in direct sliding contact is used.
That is, as described in claim 1, either the inner ring or the outer ring is a bearing that holds another ring and performs sliding rotation about the center axis of the ring.
Further, in order to solve the same problem in the conventional brake bearing, the bearing according to claim 2 which does not have rolling elements in the same manner.

According to the invention described in claim 1, since it does not have a raceway, it is possible to manufacture the bearing at a much lower cost, which is about half the conventional price.
There is no heat treatment or grinding process, which is an external process, and it can be manufactured by in-house machining only, so the delivery time is greatly shortened from half a year to one year to several weeks.
In terms of quality, there is no rolling element and the inner ring and outer ring are in surface contact with each other, so the moment resistance of the bearing is greatly improved.
From another perspective, this means that the bearing can be made smaller and lighter. In other words, if the size can be reduced, the material and processing costs are further reduced.
From the viewpoint of rotational accuracy, it is inferior to conventional rolling bearings because it is a machine tolerance for sliding rotation, but it is sufficiently satisfactory from the required accuracy of construction machinery used outdoors.
After all, the invention described in claim 1 has the disadvantage that the rotational torque is higher than that of the bearing having rolling elements, but the QCD (Q is quality, C is cost, D is delivery) is dramatically improved, and the disadvantage is It is a bearing that has a lot of merits and supplements.

According to the invention described in claim 2, it is possible to enjoy the merit of having no track as compared with the conventional brake bearing. That is, the same effect can be obtained in manufacturing cost, delivery time, and moment resistance.
Furthermore, a unique and remarkable effect resulting from the elimination of the trajectory can be obtained. The effect is that the braking force is doubled.
The conventional brake bearing has one friction surface, whereas in the present invention, the friction surface doubles to two, so the braking force also doubles.
After all, according to the present invention, it can be manufactured with a cost of about half the conventional cost and a short delivery time of several weeks, and the braking force is doubled.

According to the invention described in claim 3, since the friction material is interposed at the friction interface, a further braking effect can be obtained.

According to the invention described in claim 4, since the seal is provided in the invention described in claim 3, a more stable braking effect is guaranteed.

The bearings according to claims 5 to 7 have the same effects as the inventions according to claims 2 to 4, respectively, except that the form of the piston to be pressurized is different from the inventions according to claims 2 to 4.

Next, an embodiment of the invention described in claim 1 is shown in FIGS.
As can be seen from FIGS. 5 to 7, there are only the outer ring 2 and the inner ring 3 as components of the bearing, and one ring is held by the other ring.
An embodiment in which the inner ring 3 is held by the outer ring 2 shown in FIGS. 5 and 6 will be described in detail.
In any of the embodiments, the outer ring 2 is formed in a U-shaped cross section, and the inner ring 3 is held therein. Therefore, when viewed from the outer ring 2, the inner ring 3 is only allowed to slide and rotate about its axis, and the movement in the other left and right directions is restricted.
Since the inner ring 3 is firmly held by the outer ring 2, it is possible to receive an external force such as a moment as a bearing.
In the conventional bearing, the inner and outer rings receive external force by point or line contact via the rolling elements, but in this embodiment, they are surface contact, which is far more advantageous against external force.
Needless to say, the acceptable external force is determined by the bearing cross-sectional shape and the material strength.
The stress concentration site and corner may be appropriately rounded or chamfered.

The outer ring 2 includes two members, an outer ring main body 2a and a ring-shaped plate 2b. The outer ring main body 2a is provided with a bolt hole 6 for mounting the bearing and a bolt hole 11 for stopping the ring-shaped plate 2b. After the inner ring is inserted, the ring-shaped plate 2b is bolted. This bolt is not shown in the figure. In this state, the inner ring is held by the outer ring.
Further, a through hole may be used so that the bolt hole 6 for mounting the bearing and the bolt hole 11 for stopping the ring-shaped plate are used together.
Instead of bolting the ring-shaped plate, it may be welded.
The inner ring 3 is also provided with a bolt hole 6 for mounting the bearing.
Although the inner ring 3 is provided with a turning gear 8, it may be provided on the outer ring 2 and may be omitted if not necessary.

The contact surface between the inner ring and the outer ring may be lubricated with grease or the like in order to reduce sliding resistance, or may be coated with a lubricant such as plating or molybdenum disulfide that reduces the sliding resistance.
Further, if it is necessary to improve the material strength in order to withstand external force such as moment, heat treatment such as tempering or induction hardening may be performed.
FIG. 6 shows an example in which the restraint surface is increased to withstand further external force.
FIG. 7 shows an embodiment in which the outer ring 2 is held by the inner ring 3.

An embodiment of the invention described in claim 2 is shown in FIG.
The outer ring 2 is the same as the bearing according to claim 1 except that it holds the inner ring 3 and does not have rolling elements, but the outer ring 2 is newly provided with a ring-shaped piston 9 as shown in FIG. Has been.
This will be described below.
As shown in FIG. 8, the outer ring 2 is formed with an annular hole 12 in which a piston is provided.
Two seal grooves 13 are provided in the hole 12, and a seal 14 is inserted to prevent fluid leakage. This seal groove may be provided on the piston 9 side.
The seal 14 is an O-ring, but other seal members may be used.
A fluid such as pressure oil passes through a pipe line from a port 15 provided in at least one location on the outer ring 2 and exerts pressure on the piston bottom surface 16, and the piston 9 performs linear motion.
The top portion 17 of the piston 9 is a plane perpendicular to the traveling direction so as to be in contact with the inner ring upper surface 18, that is, in surface contact. The top portion 17 has a similar shape to that of the piston bottom surface 16 to ensure a pressure contact area.
The piston 9 may be installed in the inner ring 3 that is a movable wheel so that the outer ring 2 that is a fixed wheel is in surface pressure contact.

In order to stop the relative rotation of the inner and outer rings or keep the stopped state by the frictional force generated by the piston top portion 17, a circumferential force must be transmitted from the wheel to the piston 9. In other words, the annular piston 9 needs a locking portion that engages with the hole 12, and the portion transmits a circumferential force. On the other hand, if there is no locking part, the piston is annular, so it rotates with the other wheel and the frictional force on the friction surface makes no sense.
As shown in FIG. 8, the locking portion is provided with a plurality of convex locking portions 19a in the circumferential direction on the side wall of the hole 12, and a concave locking portion that fits the opposing piston 9. 20a is formed. In the embodiment, the locking portions are provided on the two side walls, but one side wall may be used. A concave locking portion may be formed on the side wall of the hole 12, and a convex locking portion may be formed on the opposing piston 9. Further, the locking portion may have a spline shape in which these are connected.

  Examples of different locking portions are shown in FIG. Plural locking portions 19b are provided in the circumferential direction on the bottom surface of the hole, and the piston is provided with a plurality of holes 20b for fitting with them. The protruding locking portion 19b may have any shape as long as it has the same shape as the hole 20b to be fitted, such as a cylinder or a square column. Moreover, you may provide the hole which engages with the latching | locking part which protruded conversely on the piston side in the hole bottom face. In this example, the protruding locking portion 19b is a separate part from the outer ring 2, that is, the bearing, but the locking portion 19b protruding integrally may be formed on the outer ring 2.

The operation of the piston 9 will be described with reference to FIG.
The piston 9 moves parallel to the bearing rotation axis, and the piston top portion 17 generates a frictional force by vertically and uniformly hitting a ring that does not include the piston 9, that is, the inner ring upper surface 18.
At the same time, the inner ring lower surface 21 comes into contact with the upper surface of the ring-shaped plate 2b, so that a frictional force is also generated on this surface.
Eventually, the action of the piston 9 generates a frictional force on the upper and lower surfaces of the inner ring, stops the relative rotational movement between the inner ring 3 and the outer ring 2, and holds the stopped state firmly.

When a moment acts on the inner ring, the inner ring upper surface 18 is configured to be in surface contact with the end surface of the outer ring with the piston 9 interposed therebetween, so that the outer ring end surface receives the moment.
Even when the piston 9 performs a braking action, that is, when the inner ring upper surface 18 is in pressure contact with the inner ring, the outer ring end face receives the moment, so that the piston 9 can perform a stable braking action.

In the invention described in claim 1, means for actively reducing the slip resistance of the inner and outer rings as described in paragraph 14 may be taken, but in the invention described in claim 2, the reverse In addition, means for positively increasing the slip resistance of the inner and outer rings may be taken.
For example, no lubrication may be performed, or plating or material change that increases slip resistance may be performed.

Next, an embodiment of the invention described in claims 3 and 4 will be described with reference to FIG.
The friction material 22 is a material used for a so-called brake or clutch made of fiber, resin, rubber, metal, or the like.
In this embodiment, the friction material 22 is interposed on the upper surface 18 and the lower surface 21 of the inner ring.
On the upper friction surface, the annularly formed friction material 22 is fixed to both the piston 9 and the inner ring upper surface 18 with an adhesive.
On the lower friction surface, a ring-shaped friction material 22 is also fixed to the lower surface 21 of the inner ring.
In the upper friction surface, the friction material 22 is fixed to both the piston 9 and the inner ring upper surface 18, but it may be attached only to the piston 9 or the inner ring upper surface 18.
On the contrary, on the lower friction surface, the friction material 22 is fixed only to the inner ring lower surface 21, but may be fixed to both the inner ring lower surface 21 and the ring plate upper surface.
The friction material 22 is not formed in an annular shape, but may be rectangular or circular as long as it is arranged in an annular shape along the friction surface, and may be fixed by screws or caulking.
Further, two seals 23 are arranged in a circumferential shape with the piston 9 interposed therebetween, and the space including the friction material and the mating surface is sealed.
Similarly, on the friction interface including the friction material 22 on the lower surface 21 of the inner ring, two seals 23 are arranged in a circumferential shape, and the space is sealed.
The seal 23 is a seal member such as an O-ring, dust seal, oil seal, or lip seal.
According to the invention of claim 3, the brake torque is further amplified compared to the invention of claim 2.
According to the invention described in claim 4, since the seal is provided in the invention described in claim 3, a more stable braking effect is guaranteed.

An embodiment of a bearing having a non-annular piston according to claim 5 will be described with reference to FIGS.
As shown in FIG. 11 which is an AA cross section of FIG. 10, at least one piston 9 which is not annular can be seen. The shape of the piston 9 and the hole may be any shape such as a cylindrical shape or a quadrangular prism shape, but it is needless to say that a cylindrical shape is preferable for manufacturing.
Further, the holes into which these pistons 9 enter may be arranged anywhere as long as the pipeline described later permits.
In order to supply fluid to each hole provided in the outer ring 2, a pipe line in the circumferential direction is required.
In FIG. 10, the circumferential conduit 24 is formed by forming a groove in the outer ring in the circumferential direction and then covering the cover 25 later. This cover 25 may be welded or bolted using a seal.
Then, a conduit 26 from each hole to the circumferential conduit 24 is provided.
In this way, fluid such as pressurized oil from at least one port provided in the outer ring passes through the pipes 26 from the circumferential pipes 24 to the respective holes and applies pressure to the bottom surfaces of the pistons. Has a linear motion.
A non-annular piston does not need to be provided with a locking portion compared to an annular piston. Further, if a plurality of pistons are provided, a large pressure receiving area can be secured, and the same effect as that of the annular piston can be obtained.
These pistons are installed in the outer ring 2 on the fixed side, but may be installed in the inner ring 3 on the rotation side.

In the invention according to claim 6, since a friction material is interposed at the friction interface as in FIG. 9, a further braking effect can be obtained.

According to the invention described in claim 7, since the seal is provided in the invention described in claim 6, a more stable braking effect is guaranteed.

It is sectional drawing of the conventional 4-point contact type bearing. It is principal part sectional drawing of the conventional brake bearing. FIG. 3 is an overall view of the bearing as viewed from the direction A in FIG. 2. It is principal part sectional drawing of a multilayer type brake bearing. 1 is Example 1 of the invention described in claim 1; This is Embodiment 2 of the invention described in claim 1. 10 is Example 3 of the invention described in claim 1; This is Embodiment 1 of the invention described in claim 2. This is Embodiment 1 of the invention described in claim 4. This is Embodiment 1 of the invention described in claim 5. FIG. 11 is an overall view of the bearing as viewed from the direction A in FIG.

Explanation of symbols

1 Conventional 4-point contact bearing
2 Outer ring
2a Outer ring body
2b Ring-shaped board
3 Inner ring
4 Rolling elements
5 orbit
6 Bearing mounting bolt holes
7 Seal
8 gears
9 Piston
10 Friction plate
11 Bolt hole for fixing the ring-shaped plate
12 holes
13 Seal groove
14 Seal
15 ports
16 Bottom of piston
17 Piston top
18 Inner ring top surface
19a Hole locking part
19b Hole locking part
20a Piston locking part
20b Piston locking part
21 Inner ring bottom surface
22 Friction material
23 Seal
24 circumferential pipelines
25 Cover
26 Pipe lines to each hall

Claims (7)

A bearing constituted by an inner ring and an outer ring having a coaxial axis, wherein either the inner ring or the outer ring holds the other ring and slides and rotates about the coaxial center. 2. The bearing according to claim 1, wherein the annular piston and the ring in which the annular piston is provided have a locking portion that transmits a circumferential force to each other, and the piston moves in the coaxial direction, and the top portion thereof. The bearing is characterized in that it is installed so that it can be pressed against the surface of a ring in which it is not installed.   3. The bearing according to claim 2, wherein a friction material is attached to the interface to be pressed against the surface.   4. The bearing according to claim 3, wherein a seal is attached so that foreign matter does not enter the interface to be pressed against the surface.   The at least one or more pistons that are not annular are moved in the axial direction of the bearing, and the top of each piston is installed so as to be able to press-contact a ring in which it is not installed. bearing.   6. The bearing according to claim 5, wherein a friction material is attached to the interface pressed against the surface. 7. The bearing according to claim 6, wherein a seal is attached so that foreign matter does not enter the interface to be pressed against the surface.

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