JP2015040577A - Bearing device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device which can prevent the come-off of a bearing bush from a housing resulting from a difference in linear expansion coefficient.SOLUTION: A bearing bush 2 having a length L1 shorter than a length L2 of a penetration hole 30 in an axial O-direction is inserted into the penetration hole 30 of a housing 3, ring-shaped stoppers 4a, 4b having inside diameters R3 larger than an inside diameter R0 of the bearing bush 2 are pressure-inserted into both ends 32, 32b of the penetration hole 30, and the bearing bush 2 is accommodated in the housing 3. For the bearing bush 2, there is used a material which is larger than the housing 3 and the stoppers 4a, 4b in linear expansion coefficient. For the stoppers 4a, 4b, there are used materials wherein, a difference in linear expansion coefficient between the materials and the housing 3 is smaller than a difference in linear expansion coefficient between the bearing bush 2 and the housing 3, and the materials can be set within a proper range in which a clearance is not generated between external peripheral faces 43 of the stoppers 4a, 4b and an internal peripheral face 31 of the penetration hole 30 of the housing 3 in a normal temperature lower than a use temperature of a bearing device 1.

Description

  The present invention relates to a bearing device including a bearing bush and a housing that accommodates the bearing bush, and more particularly to a bearing device that is assumed to be used in a high-temperature environment and a manufacturing method thereof.

  Conventionally, lubricating resins having excellent self-lubricating properties such as polytetrafluoroethylene (PTFE), polyamide (PA), and polyacetal (POM) have been widely used as materials for sliding members such as bearing bushes. . For example, Patent Documents 1 to 3 describe a technique for obtaining a composition for a sliding member, which has these lubricating resins as a main component and has more excellent sliding characteristics.

JP 2005-112932 A JP 2003-335842 A JP-A-6-287406

  Incidentally, the bearing bush is usually press-fitted into an insertion hole provided in the housing with a tightening margin, and is attached to an appropriate position to be attached to a vehicle body, a machine tool, a conveying device, or the like via the housing. Here, when the above-mentioned lubricating resin is used as the material of the bearing bush and a metal such as stainless steel is used as the material of the housing, the following problems may occur due to the difference in linear expansion coefficient between the two. There is.

  In other words, since the lubricating resin has a linear expansion coefficient several times to several tens of times larger than that of metal, the outer diameter of the bearing bush changes more greatly with respect to the temperature than the hole diameter of the insertion hole of the housing. For this reason, when use in a high temperature environment such as 200 degrees is assumed, the tolerance of the outer diameter of the bearing bush and the inner diameter of the through hole of the housing is determined so that an interference fit with an appropriate tightening margin is obtained at the operating temperature. Then, in an environment lower than the use temperature (for example, normal temperature), the outer diameter of the bearing bush becomes smaller than the hole diameter of the through hole of the housing, and there is a possibility that the bearing bush falls out of the housing due to a gap fit.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent the bearing bush from coming off from the housing at a temperature lower than the operating temperature due to the difference in linear expansion coefficient between the housing and the bearing bush. It is in providing a bearing device and its manufacturing method.

  In order to solve the above problems, in the present invention, a bearing bush shorter than the length of the insertion hole is inserted into the insertion hole provided in the housing, and the bearing bush is inserted into the insertion hole of the housing from one end side. A ring-shaped stopper having an inner diameter larger than the inner diameter was press-fitted. Here, the first material used for the bearing bush is a material having a larger linear expansion coefficient than the second material used for the housing and the third material used for the stopper. In addition, a material whose difference in linear expansion coefficient from the second material is smaller than the difference in linear expansion coefficient between the first material and the second material is used as the third material. Further, the difference between the linear expansion coefficients of the second material and the third material is within a range in which no gap is generated between the stopper and the housing even at a predetermined temperature lower than the operating temperature of the bearing device. Material is used. For example, a lubricating resin is used for the first material, and a metal is used for the second and third materials.

For example, the present invention is a bearing device for supporting a radial load of a rotating body,
A cylindrical bearing bush formed of a first material;
A housing formed of a second material, having an insertion hole longer than the length of the bearing bush, and wherein the bearing bush is inserted into the insertion hole;
A disconnection preventing means provided on each end side of the insertion hole of the housing, and preventing the bearing bush inserted into the insertion hole from coming out of the insertion hole;
The disconnection preventing means provided on one end side of the insertion hole of the housing,
A ring-shaped stopper press-fitted into the insertion hole of the housing, formed of a third material and having an inner diameter larger than the inner diameter of the bearing bush;
For the first material, a material having a larger linear expansion coefficient than the second material and the third material is used,
For the third material, a material having a smaller difference in linear expansion coefficient from the second material than a difference in linear expansion coefficient between the first material and the second material is used,
The stopper is
At a predetermined temperature lower than the operating temperature of the bearing device, it is fitted into the insertion hole of the housing with an interference fit having a predetermined tightening allowance.

  According to the present invention, the ring-shaped stopper in which the difference in linear expansion coefficient with the housing is smaller than the difference in linear expansion coefficient between the bearing bush and the housing is provided on one end side of the insertion hole of the housing that houses the bearing bush. Even at a predetermined temperature lower than the operating temperature of the bearing device, the fitting is performed without causing a gap between the stopper and the housing, so that the bearing bush and the insertion hole of the housing are fitted with a gap. However, it is possible to prevent the bearing bush from falling off from one end side of the insertion hole of the housing.

FIG. 1A is a front view of a bearing device 1 according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of the bearing device 1 shown in FIG. It is. FIG. 2 is an exploded view of the bearing device 1 shown in FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1A is a front view of a bearing device 1 according to the present embodiment, and FIG. 1B is a cross-sectional view of the bearing device 1 shown in FIG. It is. FIG. 2 is a component development view of the bearing device 1 according to the present embodiment.

  The bearing device 1 according to the present embodiment supports a rotating body (not shown) such as a roller and a shaft so as to be rotatable while receiving a radial load. As shown in FIGS. 1A, 1B, and 2, the bearing device 1 includes a cylindrical bearing bush 2 having a rotating body insertion hole 20, a cylindrical housing 3 that houses the bearing bush 2, and A pair of ring-shaped stoppers 4a and 4b for preventing the bearing bush 2 from falling off the housing 3 and a bolt 5 for removing one of the stoppers 4a are provided.

  The bearing bush 2 has a sliding surface 21 formed on the inner periphery (inner peripheral surface of the rotating body insertion hole 20) side, and a radial load of a rotating body (not shown) inserted into the rotating body insertion hole 20 is formed. Is supported by the sliding surface 21. The bearing bush 2 is made of a material whose main component is a lubricating resin such as PTFE, PA, or POM. As a bearing bush 2 made of such a material, for example, there is a PTFE resin bearing (Glytron (registered trademark) F bush) manufactured by Oiles Industries Co., Ltd.

  The housing 3 has a through hole 30 having a length L2 in the axis O direction which is longer than the length L1 in the axis O direction of the bearing bush 2, and the bearing bush 2 is inserted into the through hole 30. The inner diameter (diameter of the through hole 30) R2 of the housing 3 is a predetermined value under the operating temperature (for example, 200 degrees) of the bearing device 1 higher than the normal temperature (5 degrees to 35 degrees) with respect to the outer diameter R1 of the bearing bush 2. It is designed to have a suitable interference fit with an allowance.

  The housing 3 is made of a metal such as stainless steel (SUS403). The lubricating resin used as the main component of the material of the bearing bush 2 has a coefficient of linear expansion several to ten times larger than that of the metal used as the material of the housing 3 that houses the bearing bush 2. For this reason, the outer diameter R1 of the bearing bush 2 has a larger dimensional change with respect to the temperature change than the inner diameter R2 of the housing 3. Therefore, as described above, the inner diameter R2 of the housing 3 is set to a dimension that provides an appropriate interference fit with a predetermined allowance with respect to the outer diameter R1 of the bearing bush 2 under the operating temperature of the bearing device 1 higher than normal temperature. When designed, the outer diameter R1 of the bearing bush 2 becomes smaller than the inner diameter R2 of the housing 3 at a room temperature lower than the operating temperature of the bearing device 1 as shown in FIG. And the inner peripheral surface 31 of the housing 3, a gap ΔR may be formed, and the bearing bush 2 may be fitted into the housing 3 with a gap.

  The stoppers 4a and 4b have an inner diameter R3 larger than the inner diameter R0 of the bearing bush 2, and are respectively press-fitted into both end portions 32a and 32b of the through hole 30 of the housing 3 in which the bearing bush 2 is inserted.

  In consideration of changes in the length of the bearing bush 2 due to temperature changes, each of the stoppers 4a and 4b has one end face (end face on the bearing bush 2 side) 41b and a bearing facing the end face 41b at room temperature. It is preferable to press-fit to an appropriate gap ΔL between the end faces 23a and 23b of the bush 2. In this way, it is possible to prevent the bearing bush 2 from extending in the direction of the axis O and the stoppers 4 a and 4 b from being removed from the through 30 of the housing 3 under the operating temperature of the bearing device 1 higher than normal temperature.

  The stoppers 4a and 4b are made of a material having a smaller linear expansion coefficient than the material of the bearing bush 2, and the difference in the linear expansion coefficient from the material of the housing 3 is different between the material of the bearing bush 2 and the material of the housing 3. A material smaller than the difference in linear expansion coefficient is used. Further, the material of the stoppers 4a and 4b and the material of the housing 3 have an outer peripheral surface of the stoppers 4a and 4b that has a difference in linear expansion coefficient between the service temperature of the bearing device 1 and a room temperature lower than the service temperature. 43 and a material that falls within an appropriate range that does not cause a gap between the inner peripheral surface 31 of the through-hole 30 of the housing 3 (for example, the linear expansion coefficient of the material of the bearing bush 2> the material of the material of the stoppers 4a and 4b). Expansion coefficient ≧ linear expansion coefficient of the material of the housing 3). However, if the stoppers 4a and 4b are made of the same material as the housing 3, the stoppers 4a and 4b and the housing 3 are different from each other because the stoppers 4a and 4b may not be detached from the housing 3 because they are joined. A material is preferably used. For example, when the housing 3 having an inner diameter of several mm to several tens of mm is formed of stainless steel (SUS403), the stoppers 4a and 4b are formed of a metal other than stainless steel such as a copper alloy.

  Further, one stopper 4a is formed with a screw hole 42 penetrating both end faces 41a and 41b of the stopper 4a at a position on one end face 23a of the bearing bush 2 inserted into the through hole 30 of the housing 3. Yes. One stopper 4 a can be removed from the housing 3 by screwing the bolt 5 into the screw hole 42 and pressing the tip of the bolt 5 against one end surface 23 a of the bearing bush 2.

  The bearing device 1 having the above configuration is manufactured, for example, as follows.

  First, the other stopper 4 b is press-fitted into the through hole 30 from the end 32 b side so that the other stopper 4 b is positioned at the other end 32 b of the through hole 30 of the housing 3. Next, the bearing bush 2 is inserted into the through hole 30 from the one end 32 a side of the through hole 30 of the housing 3 in the axis O direction. Then, the one stopper 4 a is press-fitted into the through hole 30 from the end 32 a side so that the one stopper 4 a is positioned at one end 32 a of the through hole 30 of the housing 3. Thus, the bearing bush 2 is accommodated in the through hole 30 of the housing 3 while exposing the rotating body insertion hole 20 surrounded by the sliding surface 21 for slidingly supporting the rotating body.

  When the bearing bush 2 inserted into the through hole 30 of the housing 3 is replaced, the bolt 5 is screwed into the screw hole 42 of one stopper 4a, and the tip of the bolt 5 is connected to one end face 23a of the bearing bush 2. The one stopper 4 a is removed from the through hole 30 of the housing 3 by pressing against the through hole 30. As described above, since the bearing bush 2 and the through hole 30 of the housing 3 are fitted with a clearance at room temperature, the bearing bush 2 can be easily inserted and removed from the through hole 30 of the housing 3.

  The embodiment of the present invention has been described above.

  According to the present embodiment, the pair of stoppers 4 a and 4 b having a smaller difference in linear expansion coefficient from the housing 3 than the difference in linear expansion coefficient between the bearing bush 2 and the housing 3 are provided at both ends of the through hole 30 of the housing 3. The bearing bush 2 and the through hole 30 of the housing 3 are fitted to the portions 32a and 32b with an appropriate interference fit having a predetermined allowance at both the use temperature of the bearing device 1 and the room temperature lower than the use temperature. Even in a room temperature environment in which the gap fits, both ends 32a and 32b of the insertion hole 30 of the housing 3 and the pair of stoppers 4a and 4b are interference fits, so that the bearing bush 2 can be prevented from falling off from the housing 3. . As a result, in the bearing device 1 assumed to be used in a high temperature environment, a metal such as stainless steel is used as the material of the housing 3, and the linear expansion coefficient is several times to ten times that of the metal as the material of the bearing bush 2. Even when a lubricating resin such as PTFE, PA, or POM that is several times larger is used, the bearing bush 2 can be reliably accommodated in the housing 2 in a normal temperature environment lower than the operating temperature of the bearing device 1. It becomes possible. For example, a predetermined temperature at which the difference in coefficient of linear expansion between the material of each stopper 4a, 4b and the material of the housing 3 is lower than the actual operating temperature of the bearing device 1 (temperature at which assembly and maintenance work is performed, for example, room temperature). In this case, the material of the stoppers 4a and 4b and the material of the housing 3 are set so as to be within an appropriate range in which no gap is generated between the outer peripheral surface 43 of the stoppers 4a and 4b and the inner peripheral surface 31 of the through hole 30 of the housing 3. Can be prevented from falling off the bearing bush 2 from the housing 3 at room temperature.

  In the present embodiment, the stopper 4a can be removed from the housing 3 by screwing the bolt 5 into the screw hole 42 of the stopper 4a and pressing the tip of the bolt 5 against the end surface 23a of the bearing bush 2. Therefore, the burden of replacement work of the bearing bush 2 can be reduced.

  In addition, this invention is not limited to said embodiment, Many deformation | transformation are possible within the range of the summary.

  For example, in the above embodiment, the other stopper 4b is also provided with a screw hole 42 similar to the one stopper 4a, and the bolt 5 is screwed into the screw hole 42 so that the tip of the bolt 5 is a bearing. The other stopper 4 b may be removed from the through hole 30 of the housing 3 by pressing against the other end surface 23 b of the bush 2. By doing so, the bearing bush 2 can be exchanged from either end 32a, 32b side of the through hole 30 of the housing 3, so that the burden of the exchange work of the bearing bush 2 can be further reduced. it can.

  In the above embodiment, the cylindrical housing 3 is used. However, the housing 3 only needs to have a through hole 30 in which the bearing bush 2 is accommodated, and the outer shape of the housing 3 is an object to be attached. Anything that is suitable for attachment to the body may be used.

  Further, in the above embodiment, if it is not assumed that the other stopper 4b is removed from the through hole 30 of the housing 3, the material of the other stopper 4b is used as the material of the housing 3 and the other stopper 4b is used. The stopper 4 b may be joined to the through hole 30 of the housing 3. Alternatively, the other stopper 4 b may be formed integrally with the housing 3 as a flange projecting from the inner peripheral surface 31 of the housing 3 toward the inner diameter direction of the housing 3.

  1: bearing device, 2: bearing bush, 3: housing, 4a, 4b: stopper, 5: bolt, 20: rotating body insertion hole of bearing bush, 21: sliding surface of bearing bush, 22: outer peripheral surface of bearing bush 23a, 23b: end face of bearing bush, 30: through hole of housing, 31: inner peripheral surface of housing, 32a, 32b: end of through hole of housing, 41a, 41b: end face of stopper, 42: screw of stopper Hole 43: Outer peripheral surface of stopper

Claims (8)

A bearing device for supporting a radial load of a rotating body,
A cylindrical bearing bush formed of a first material;
A housing formed of a second material, having an insertion hole longer than the length of the bearing bush, and wherein the bearing bush is inserted into the insertion hole;
A disconnection preventing means provided on each end side of the insertion hole of the housing, and preventing the bearing bush inserted into the insertion hole from coming out of the insertion hole;
The disconnection preventing means provided on one end side of the insertion hole of the housing,
A ring-shaped stopper press-fitted into the insertion hole of the housing, formed of a third material and having an inner diameter larger than the inner diameter of the bearing bush;
For the first material, a material having a larger linear expansion coefficient than the second material and the third material is used,
For the third material, a material whose difference in linear expansion coefficient from the second material is smaller than the difference in linear expansion coefficient between the first material and the second material is used,
The stopper is
The bearing device is fitted into the insertion hole of the housing by an interference fit having a predetermined allowance at a predetermined temperature lower than the operating temperature of the bearing device. The bearing device according to claim 1,
The disconnection preventing means provided on the other end side of the insertion hole of the housing is,
The bearing device according to claim 1, wherein the bearing device is a ring-shaped stopper that is the same as the slip-off preventing means provided on one end side of the insertion hole of the housing. The bearing device according to claim 1,
The disconnection preventing means provided on the other end side of the insertion hole of the housing is,
A bearing device that is a flange projecting from an inner peripheral surface of the housing toward an inner diameter direction of the housing. The bearing device according to any one of claims 1 to 3,
The first material is a lubricating resin,
Said 2nd and 3rd raw material is a metal. The bearing apparatus characterized by the above-mentioned. The bearing device according to claim 4,
The second material is stainless steel,
Said 3rd raw material is a copper alloy. The bearing apparatus characterized by the above-mentioned. The bearing device according to any one of claims 1 to 5,
The stopper provided on one end side of the insertion hole of the housing as the removal preventing means has a screw hole that penetrates both end surfaces at a position on the end surface of the bearing bush inserted into the insertion hole of the housing. Is formed,
The bearing device further comprising a screw that is screwed into the screw hole and pushes the stopper from the insertion hole of the housing by pressing the tip against the end face of the bearing bush. A method of manufacturing a bearing device that supports a radial load of a rotating body,
Inserting the bearing bush shorter than the length of the insertion hole into the insertion hole provided in the housing formed of the second material having a lower linear expansion coefficient than the first material used for the bearing bush,
The difference in linear expansion coefficient with the second material is smaller than the difference in linear expansion coefficient between the first material and the second material, and at a predetermined temperature lower than the operating temperature of the bearing device. A ring-shaped stopper having a larger inner diameter than the inner diameter of the bearing bush, which is formed of a third material that fits into the insertion hole of the housing with an interference fit with a predetermined tightening allowance. A method of manufacturing a bearing device, comprising: press-fitting from one end side of the insertion hole of the housing. It is a manufacturing method of the bearing device according to claim 7,
The stopper is formed with a screw hole penetrating both end surfaces at a position on the end surface of the bearing bush inserted into the insertion hole of the housing,
A method for manufacturing a bearing bush, wherein a screw for pushing the stopper from an insertion hole of the housing is screwed into the screw hole by pressing the tip of the screw against an end surface of the bearing bush.

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