JP2007232035A - Pressurization controlling bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately perform a pressurization controlling operation without being affected by a fitting frictional force of a bearing inner ring and a bearing outer ring. <P>SOLUTION: In the pressurizing controlling bearing device, the bearing inner ring 3 is supported on a shaft 8 side, the bearing outer ring 1 is supported on a housing 6 side surrounding the shaft 8, and the bearing pressure is adjusted to a predetermined pressure by an inner ring thruster 10 screwed to the shaft 8 side which presses the bearing inner ring 3 in the axial direction, and an outer ring thruster 11 screwed to the housing 6 side which presses the bearing outer ring 1 in the axial direction. A pressure automatic adjusting spacer 4 is provided connected in series with the housing 6 for suppressing change in the bearing pressure caused by the difference in extension/contraction amount in the axial direction of the housing 6 and the shaft 8 by a temperature change, by extending/contracting in the axial direction by this temperature change on the housing 6 side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pressurizing management bearing device having a function of suppressing a pressurization change due to a temperature change.

  A bearing device having a function of suppressing a pressure change due to a temperature change, a so-called pressure management bearing device, is used for a high-precision support mechanism of a mirror used in a satellite under a vacuum cryogenic temperature such as space. However, as an example, there is an angular ball bearing device described in JP-A-5-79514 (Patent Document 1).

  The angular ball bearing device described in Patent Document 1 depends on temperature changes by providing spacers having different linear expansion coefficients (hereinafter abbreviated as CTE) on both sides in the axial direction of the inner ring or outer ring of the ball bearing. By suppressing / preventing an increase in pressurization (change in pressurization) due to a change in the bearing gap, suppression / increase of the resistance torque of the bearing is prevented.

Japanese Patent Laid-Open No. 5-79514 (FIG. 1 and explanation thereof)

  As described above, the angular ball bearing device described in Patent Document 1 is provided with spacers having different CTEs on both sides in the axial direction of the inner ring or the outer ring of the ball bearing, so that the pressure applied by the change in the bearing gap due to the temperature change is increased. By suppressing / preventing the increase (change in pressure applied), the resistance torque of the bearing is suppressed / increased. However, if the outer ring and inner ring of the ball bearing are fitted together, the outer ring and inner ring will not move unless a force greater than the frictional force acts in the axial direction. Therefore, it is preferable that the pressurization management operation for keeping the pressurization as described above within a predetermined range even under severe temperature changes can be accurately performed without being influenced by the frictional force.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to enable a pressure control operation to be performed accurately without being influenced by the frictional force.

  In the pressurized management bearing device according to the present invention, a bearing inner ring is supported on the shaft side, a bearing outer ring is supported on the housing side surrounding the shaft, and is screwed to the shaft side to press the bearing inner ring in the axial direction. In a pressurized management bearing device that is adjusted to a predetermined bearing pressure by an inner ring retainer and an outer ring retainer that is screwed to the housing side and presses the bearing outer ring in the axial direction, A pressurization management bearing device provided with a pressurization automatic adjustment spacer that suppresses a change in bearing pressure due to a difference in axial expansion / contraction between the housing and the shaft on the housing side by axial expansion / contraction due to the temperature change. The change of the bearing pressure due to the difference in the amount of expansion and contraction in the axial direction between the housing and the shaft due to a temperature change is suppressed / prevented.

  The present invention includes a bearing inner ring supported on a shaft side, a bearing outer ring supported on a housing side surrounding the shaft, an inner ring pressing member that is screwed to the shaft side and presses the bearing inner ring in an axial direction, and a housing side. In a pressurizing management bearing device that is adjusted to a predetermined bearing pressurization by an outer ring presser that is screwed and presses the bearing outer ring in the axial direction, the shaft of the housing and the shaft that are coupled in series with the housing and that changes due to temperature change Since there is an automatic pressure adjustment spacer that suppresses changes in the bearing pressure due to differences in direction expansion and contraction on the housing side by axial expansion and contraction due to the temperature change, the bearing pressure is kept within a predetermined value under temperature changes. Therefore, it is possible to accurately perform the pressure management operation that is automatically performed without being influenced by the frictional force of the bearing outer ring and the bearing inner ring.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS. 1 is a bottom view showing an application example of a pressurized management bearing device, a side view showing a part of FIG. 1 on an enlarged scale, FIG. 3 is a longitudinal side view showing an example of a pressurized management bearing device in section, and FIG. It is a function explanatory drawing which compares the example of the state before a temperature change with the example of the state after a temperature change, and shows it without displaying a cross section. 1 to 4, the same reference numerals indicate the same parts.

For example, in a space telescope mounted on a satellite or the like, as shown in FIGS. 1 and 2, the mirror M is supported at a predetermined angle by, for example, three support devices SD, and each support device SD is well known. It has a 4-axis configuration.
For such a support device, the pressure control bearing device as described above is used.

  In addition, the environmental temperature of the pressurization management bearing device applied to the space telescope mounted on the satellite or the like is significantly different between the case before the satellite is launched and the case in the orbit after the satellite is launched. The environmental temperature on the ground before the launch is, for example, 15 ° C., the environmental temperature on the orbit after the launch is about 5 ° K, and the difference is 300 degrees. Generally, when it is mounted on a satellite and launched into outer space, the environmental temperature decreases by about 300 degrees, so that normally the bearing torque increases and the bearing function decreases. That is, the pressurization management bearing device applied to the satellite in outer space suppresses / prevents a decrease in bearing function by suppressing / preventing an increase in the pressurization because the pressurization increases and the bearing function decreases. One conventional means is Japanese Patent Application Laid-Open No. 2003-228620, which is the subject described above.

  The pressurization management bearing device according to Embodiment 1 of the present invention provides a pressurization management bearing device from a new viewpoint that is not affected by the friction of the bearing outer ring and the bearing inner ring in Patent Document 1 described above. An example of a specific structure will be described below with reference to FIG.

  As shown in FIG. 3, the pressurizing management bearing device according to the first embodiment of the present invention includes a bearing outer ring 1, a bearing ball 2, a bearing inner ring 3, a pressurizing automatic adjustment spacer 4, a bearing holder 5, a bearing housing 6, and a bolt. 7, a shaft 8, a spacer 9, an inner ring retainer 10, and an outer ring retainer 11.

  The bearing outer ring 1 is fixed to the bearing housing 6 by the bearing holder 5 and the outer ring retainer 11.

  The bearing inner ring 3 is fixed to the shaft 8 side with an appropriate pressure applied to the bearing ball 2 by the shaft 8 and the inner ring retainer 10.

As shown in the figure, the automatic pressure adjusting spacer 4 is interposed between the bearing holder 5 forming a pair located at both axial ends of the shaft 8 and the bearing housing 6 at the center.
Further, as shown in the drawing, each of the automatic pressure adjusting spacers 4 includes a plurality of bolts 7 whose front ends are screwed into the bearing housing 6 and whose heads are in contact with the bearing holder 5. And the bearing housing 6.
Moreover, each said pressurization automatic adjustment spacer 4 is the same annular shape as the said bearing holder 5 and the said bearing housing 6, as shown in the figure.
Each of the automatic pressure adjusting spacers 4 has a uniform axial thickness over all of the circumferential direction and the radial direction, and both axial end surfaces of the self-pressurizing automatic adjustment spacers 4 The housing 6 is in surface contact with both the corresponding axial end surface of the housing 6 and the corresponding axial end surface of the corresponding bearing holder 5.
Further, a gap gap1 exists between the inner peripheral surface of the bolt through-hole through which the bolt 7 of each pressurizing pressure adjusting spacer 4 passes in a loosely fitted state and the outer peripheral surface of the thread of the bolt 7. Similarly, a gap gap2 exists between the inner peripheral surface of the bolt through hole through which the bolt 7 of the bearing holder 5 passes in a loose fit state and the outer peripheral surface of the neck portion of the bolt 7.

  As shown in the figure, an inner ring corresponding surface 8s is formed at each boundary between the large-diameter outer peripheral surface of the center portion and the small-diameter outer peripheral surfaces of both end portions of the shaft 8, and each inner ring corresponding surface 8s A gap gap3 exists between the corresponding end surface of the corresponding bearing inner ring 3 in a predetermined bearing pressure state.

  Similarly, each bearing holder 5 has an outer ring corresponding surface 5s at each boundary between a small-diameter inner peripheral surface on the axis center line CT1 side and a large-diameter inner peripheral surface on the opposite axis center line CT1 side as shown in the figure. The corresponding end surface of the corresponding bearing outer ring 1 is pressed against the outer ring corresponding surface 5s by the bearing holder 5 in a predetermined bearing pressure state.

  The outer ring retainers 11 are screwed onto the large-diameter inner peripheral surface of each bearing holder 5, and each outer ring retainer 11 presses the corresponding bearing outer ring 1 against the corresponding outer ring corresponding surface 5s. is doing.

  The inner ring retainers 10 are screwed onto the small-diameter outer peripheral surfaces at both ends of the shaft 8, and the inner ring retainers 10 connect the corresponding bearing inner rings 3 via the annular spacers 9 in the axial direction. Pressing in the direction of the center line CT1.

  The surfaces of the bearing outer ring 1 and the bearing inner ring 3 that receive the bearing balls 2 constitute angular ball bearings that are inclined in the same direction with respect to the center line CT2 of the shaft 8, on the other hand, as described above. Further, a gap gap3 exists between the inner ring corresponding surface 8s of the shaft 8 and the end surface of the bearing inner ring 3. Accordingly, the bearing outer ring 1 is firmly fixed to the bearing holder 5 with high rigidity, and as a result, is firmly fixed to the bearing housing 6 with the bolt 7 through the automatic pressure adjusting spacer 4 with high rigidity. The bearing inner ring 3 is pressed in the direction of the axial center line CT1 by the inner ring retainer 10, so that the bearing ball 2 is pressed against the bearing outer ring 1 with a predetermined pressure. That is, the inner ring retainer 10 functions as a bearing pressure adjusting screw.

  When the environmental temperature changes in the state shown in FIG. 3, a difference in linear expansion coefficient between the bearing ball 2, the bearing outer ring 1, and the bearing inner ring 3, and a difference in linear expansion coefficient between the shaft 8 and the bearing housing 6. Thus, if the bearing outer ring 1 does not move in the direction of the axial center line CT1, the bearing pressure becomes excessive and the bearing resistance torque increases (during cooling from ambient temperature to cryogenic temperature).

  In the first embodiment, in order to move the bearing outer ring 1 in the axial direction without friction due to thermal deformation, the automatic pressure adjustment with a different linear expansion coefficient (hereinafter abbreviated as CTE) from the shaft 8 is performed. The spacer 4 is coupled / fastened between the bearing holder 5 and the bearing housing 6 by the bolt 7 as shown. Thereby, even if a frictional force due to interference (tightening allowance) or the like acts between the bearing outer ring 1 and the bearing holder 5, the bearing outer ring 1 is As indicated by a dotted line in FIG. 4, the bearing holder 5 can move in the direction of the axial center line CT1. The contact angle of the bearing ball 2 also changes from θ1 to θ2, as shown in FIG.

  In FIG. 4, the solid line indicates the state of each part of the pressurization management bearing device when the environmental temperature is the ground temperature, for example, 15 ° C., and the dotted line indicates the pressurization management when the environmental temperature is a temperature of several degrees K in a satellite in outer space. The state of each part of the bearing device is shown. When the pressurized pressure management bearing device is cooled to a temperature lower than the ground temperature, for example, 15 ° C. by nearly 300 ° C., as shown by the dotted line, the pressurized pressure adjusting spacer 4 is thermally contracted to reduce its axial thickness. As a result, the bearing outer ring 1 moves in the direction of the axial centerline CT1 together with the bearing holder 5 via the bolt 7 with respect to the reference surface SS, and is thus cooled to a temperature close to 300 degrees. Even if it is, it is automatically managed to a predetermined bearing pressure almost equal to that before cooling.

  Further, the bolt 7 is made of the same material as that of the pressurizing automatic adjustment spacer 4 to prevent the tightening force from being lowered.

In the first embodiment of the present invention, the spacer 9 and the spacer 9 are controlled so as to be automatically managed at a predetermined bearing pressure almost equal to that before cooling even when the temperature is lowered to a temperature close to 300 degrees as described above. The magnitude relationship of CTE (linear expansion coefficient) of the bearing housing 6, the bearing outer ring 1, the bearing inner ring 3, the shaft 8, and the bearing ball 2 is as follows. That is, the spacer 9> the bearing housing 6, the bearing outer ring 1, the bearing inner ring 3,> the shaft 8> the bearing ball 2. Since the CTE of the bearing ball 2 is the smallest, after cooling, the bearing ball 2 has a large CTE (the spacer 9, the bearing housing 6, the bearing outer ring 1, as shown by the dotted line in FIG. 4. Etc.) is relatively large.
In order to make the size relationship, for example, the spacer 9 is aluminum, the bearing housing 6, the bearing outer ring 1, and the bearing inner ring 3 are stainless steel, the shaft 8 is titanium, and the bearing balls 2 are Ceramic may be used.

Also, to be automatically managed approximately equal to a predetermined bearing preload and before being cooled to 300 degrees near the lower temperature cooling as described above, the axial thickness L ₂ of each spacer 9 the following You can find it like this.

The length in the axial direction of the bearing housing 6 before the temperature change (the length between the outer ring corresponding surfaces 5s and 5s) is L, the length of the housing 6 after the temperature change is L ', and the shaft before the temperature change the axial length of 8 (the axial length of the large-diameter outer peripheral surface of the central portion of the shaft 8) the L _0, the length L ₀ of the coaxial 8 after the temperature change _', CTE of the bearing housing 6 Α, the CTE value of the shaft 8 is α ₀ , the axial thickness of the bolt 7 through portion of each bearing holder 5 is L ₁ , the CTE value of the bolt 7 through portion is α ₁ , The axial thickness of the automatic adjustment spacer 4 is L ₂ , the CTE value of each pressure automatic adjustment spacer 4 is α ₂ , and the length between the contact surfaces of the bearing housing 6 with the both pressure automatic adjustment spacers 4 L _3, the CTE value of the contact surface between section alpha _3, axial displacement amount due to the temperature change of the bearing gap (the bearing Δa is equivalent to the amount of displacement of the wheel 1 in the axial centerline CT1 direction, and the amount of displacement of the bearing clearance in the radial direction accompanying the temperature change (before and after the temperature change between the bearing ball 2 and the bearing outer ring 1). Is equivalent to the displacement amount of each contact point of Δr,
When α> α ₀ and temperature change ΔT <0,
L ₀ ′ −L ′ = 2Δa (Equation 1)
It becomes.

Here, it is possible to manage the desired bearing preload by obtaining an axial thickness L ₂ of the respective pressurized automatic adjustment spacers 4 to satisfy the Δa of formula 1.
That means
ΔL ₀ = L ₀ ′ −L ₀ = α ₀ L ₀ ΔT (Equation 2)
ΔL = L′−L = (2α ₁ L ₁ + 2α ₂ L ₂ + α ₃ L ₃ ) ΔT (Equation 3)

Here, assuming that L ₀ = L,
L ₀ ′ −L ′ = 2Δa = (α ₀ L ₀ −2α ₁ L ₁ −2α ₂ L ₂ −α ₃ L ₃ ) ΔT (Equation 4)
Thus, from Equation 4, the axial thickness L ₂ of the pressurizing automatic adjustment spacer 4 obtained by Equation 5 below.
L ₂ = ((2Δa / ΔT) + α ₀ L ₀ −2α ₁ L ₁ −α ₃ L ₃ ) / 2α ₂ ... (Formula 5)

  As described above, in the first embodiment of the present invention, the bearing inner ring 3 is supported on the shaft 8 side, the bearing outer ring 1 is supported on the housing 6 side surrounding the shaft 8, and is screwed onto the shaft 8 side. A pressurized pressure management bearing that is adjusted to a predetermined bearing pressure by an inner ring retainer 10 that presses the bearing inner ring 3 in the axial direction and an outer ring retainer 11 that is screwed into the housing 6 and presses the bearing outer ring 1 in the axial direction. In the apparatus, a change in bearing pressure due to a difference in the amount of expansion and contraction between the housing 6 and the shaft 8 due to a temperature change coupled in series with the housing 6 is changed to the side of the housing 6 by an axial expansion and contraction due to the temperature change. It is a pressurization management bearing device provided with a pressurization automatic adjustment spacer 4 to be suppressed in step S2. Thus, as described above, the pressure management operation can be performed accurately without being affected by the frictional force of engagement between the bearing inner ring 3 and the bearing outer ring 1.

Embodiment 2. FIG.
The bearing inner ring 3 is supported on the shaft 8 side, the bearing outer ring 1 is supported on the housing 6 side surrounding the shaft 8, and the inner ring retainer is screwed to the shaft 8 side to press the bearing inner ring 3 in the axial direction. 10 and a pressure management bearing device that is adjusted to a predetermined bearing pressure by an outer ring presser 11 that is screwed to the housing 6 side and presses the bearing outer ring 1 in the axial direction. Pressure is provided with an automatic pressure adjusting spacer that suppresses a change in bearing pressure due to a difference in the amount of expansion / contraction between the housing 6 and the shaft 8 due to a change on the shaft side due to the expansion / contraction in the axial direction due to the temperature change. The management bearing device also has an effect equivalent to that of the first embodiment of the present invention described above.

It is a figure which shows Embodiment 1 of this invention, and is a bottom view which shows the example of application of a pressurization management bearing apparatus. It is a figure which shows Embodiment 1 of this invention, and is a side view which expands and shows a part of FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of this invention, and is a vertical side view which shows an example of a pressurized management bearing apparatus in a cross section. It is a figure which shows Embodiment 1 of this invention, Comprising: The example of a state before a temperature change and the example of a state after a temperature change are compared, and it is a function explanatory drawing shown without showing a cross section.

Explanation of symbols

1 bearing outer ring,
2 bearing balls,
3 Bearing inner ring,
4 Automatic pressure adjusting spacer,
5 Bearing holder,
6 Bearing housing,
7 volts,
8 axes,
9 Spacer,
10 Inner ring retainer,
11 Outer ring presser.

Claims (3)

  A bearing inner ring is supported on the shaft side, a bearing outer ring is supported on the housing side surrounding the shaft, an inner ring retainer that is screwed to the shaft side and presses the bearing inner ring in the axial direction, and is screwed to the housing side. In a pressurization management bearing device that is adjusted to a predetermined bearing pressurization by an outer ring presser that presses the bearing outer ring in the axial direction, the amount of expansion and contraction in the axial direction between the housing and the shaft that is coupled in series with the housing due to temperature change A pressure management bearing device is provided with an automatic pressure adjustment spacer that suppresses a change in bearing pressure due to the difference in the axial direction due to the temperature change on the housing side.   A bearing inner ring is supported on the shaft side, a bearing outer ring is supported on the housing side surrounding the shaft, an inner ring retainer that is screwed to the shaft side and presses the bearing inner ring in the axial direction, and is screwed to the housing side. In a pressurization management bearing device that is adjusted to a predetermined bearing pressurization by an outer ring presser that presses the bearing outer ring in the axial direction, the amount of expansion and contraction in the axial direction between the housing and the shaft that is coupled in series with the shaft and changes due to temperature change A pressurizing management bearing device comprising a pressurization automatic adjustment spacer that suppresses a change in bearing pressurization due to a difference in the axial direction by expansion and contraction in the axial direction due to the temperature change.   3. The pressurizing management bearing device according to claim 1 or 2, wherein the pressurizing automatic adjustment spacer is connected by a screw made of the same material as the pressurizing automatic adjustment spacer. Pressure management bearing device.

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