JP2002195281A - Support structure of rotating shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a support structure of a rotating shaft capable of reducing a load or impact to be borne by a bearing for rotatably supporting a shaft even in the case where a support structure is used for such an application that the bearing bears, during rotation of shaft is stopped, the load or impact heavier than that during rotation. SOLUTION: This support structure of the rotating shaft is provided with a fixing part 12 arranged to at least one side edge face 10A of a shaft 10 (30) or to a flange face 41A provided on the shaft 10 (30) via a clearance C, and is formed such that the clearance C becomes shorter than the distance that the shaft 10 (30) is displaced when an excessive axial load is applied thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary shaft supporting structure for rotatably supporting a shaft via a rolling bearing.

[0002]

2. Description of the Related Art Conventionally, a bearing for rotatably supporting a shaft is usually selected based on a torque generated by a motor which is a driving source of the shaft. However, the axis is
When used in an application in which an axial load or impact greater than the load received during rotation is received during a stop, such a load or impact is also applied to a bearing that supports the shaft in rotation. Therefore, it is necessary to select a bearing based on the load and the impact value. For this reason, the bearing's original purpose of "supporting the rotating shaft" has an excessive load capacity, resulting in an expensive bearing and a tendency to increase the size of the bearing. Was.

[0003] Further, the support structure of the rotating shaft by the bearing is configured such that a load or an impact received while the shaft is stopped generates a drag against a rotating force (torque) for rotating the shaft. The fact is that it is not.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve such a conventional problem.
Reduce the load and impact on the bearings that support the shaft, even when used in applications where the shaft receives a greater load or impact than the load received while the shaft is rotating, even when the shaft is stopped. It is an object of the present invention to provide a support structure for a rotating shaft that can perform the above-described steps.

It is another object of the present invention to provide a rotating shaft support structure having a resistance to a rotating force (torque) for rotating the shaft due to a load or an impact received while the shaft is stopped.

[0006]

In order to achieve this object, the present invention relates to a rotating shaft support structure for rotatably supporting a shaft via a rolling bearing, wherein the rotating shaft has at least one end face of the shaft or the shaft. A fixed portion provided with a gap with respect to the flange surface provided in the above, the gap is formed smaller than the distance that the shaft is displaced when an excessive axial load is applied to the shaft. The present invention provides a supporting structure for a rotating shaft.

[0007] In the rotating shaft support structure having this configuration,
An excessive axial load or impact is applied to the shaft, and the end surface or the flange surface of the shaft comes into contact with the fixed portion while the shaft is displaced in this direction due to the load or impact.
Therefore, the load and the impact can be received by the fixed portion, and the load and the impact applied to the rolling bearing can be reduced.

Further, since the shaft is locked by abutting on the fixed portion, the amount of displacement of the shaft due to the load or impact can be limited.

Furthermore, since the rotational frictional force of the shaft increases when the end surface or flange surface of the shaft comes into contact with the fixed portion, the torque is detected to detect that an excessive load or impact is applied. You can also.

[0010] Further, the support structure of the rotating shaft according to the present invention comprises:
A magnet provided on the outer periphery of the shaft and an electromagnetic coil provided on the fixed part and provided concentrically with the magnet may further be provided, and the magnet and the electromagnetic coil may constitute an electromagnetic motor.

An elastic member may be interposed between the inner ring or the outer ring of the rolling bearing and the fixed portion. With this configuration, a preload can be applied to the rolling bearing. Examples of the elastic member include a coil spring, a corrugated washer, a dish-shaped washer, and a leaf spring.

Further, a spiral groove may be provided on the outer periphery of the shaft to form a male screw, and the male screw may be provided with a female screw to be screwed with the male screw to convert the rotational motion into a linear motion. Alternatively, a spiral groove may be provided on the inner periphery of the shaft to form a female screw, and the female screw may be provided with a male screw to be screwed with the female screw to convert the rotational motion into a linear motion.

[0013] Further, the support structure of the rotating shaft according to the present invention comprises:
An engagement portion may be provided on an end surface or a flange surface of the shaft, and a non-engagement portion that engages with the engagement portion may be further provided on the fixed portion. The engagement portion and the non-engagement portion can be formed, for example, from irregularities that can be fitted to each other. The engaging portion and the non-engaging portion can be arranged so as to engage in an angular phase and an angular pitch at which the rotating shaft stops by the magnetic force of the magnet when the stepping motor is not excited. With this configuration, it is possible to improve the resistance against the rotational force (torque) that attempts to rotate the shaft due to the load or impact received while the shaft is stopped.

Further, in the rotating shaft support structure according to the present invention, the ON / OF corresponding to the engaging portion and the non-engaging portion is provided.
At least one sensor that outputs the F signal can be provided. With this configuration, the rotation angle of the shaft can be detected.

Further, a through-hole may be opened in an end face or a flange of the shaft, and a position of the through-hole may be monitored by the sensor to detect a rotation angle of the shaft.

Further, in the rotating shaft support structure according to the present invention, an electric contact can be constituted by the end surface or the flange surface of the shaft and the fixed portion which comes into contact with the end surface or the flange surface. With this configuration, it is possible to electrically detect that an excessive load or impact has been received.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a rotation shaft support mechanism according to an embodiment of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional view showing a rotary shaft support structure according to Embodiment 1 of the present invention. The rotating shaft support structure shown in FIG. 1 has a structure in which the shaft 10 is rotatably supported by ball bearings 11A and 11B as rolling bearings disposed at both ends of the shaft 10. On one end surface 10A side of the shaft 10, a fixed portion 12 is disposed with a predetermined gap C from the end surface 10A. This gap C is
In addition, when an excessive axial load or impact exceeding the static rated load is applied, the shaft 10 is designed to be smaller than a distance at which the shaft 10 is displaced by the load or impact force.

The other end face 10B of the shaft 10 has
A rotating body (not shown) is connected through an opening provided at the left end of the housing margin.

In the ball bearings 11A and 11B, the inner rings 14A and 14B are fixed to the shaft 10, and the outer rings 15A and 15B are fixed to the housing 13.

In this rotary shaft support structure, an excessive axial load or impact is applied to the end face 10B of the shaft 10, and the shaft 10 is displaced in this direction (indicated by an arrow in FIG. 1) due to the load or impact. , The end face 10 </ b> A of the shaft 10 comes into contact with the fixing portion 12. Therefore, the load and the impact can be received by the fixing portion 12, and the load and the impact applied to the ball bearing 11A can be reduced. As a result, it is possible to prevent the ball bearing 11A from being broken,
Since the selection of the ball bearings 11A and 11B can be performed based on a normal load (a radial load which is an original purpose), miniaturization can be achieved.

Further, since the shaft 10 abuts on the fixed portion 12 and is locked, the amount of displacement due to the load or impact can be reduced.

Further, since the rotational frictional force of the shaft 10 increases when the end face 10A comes into contact with the fixed portion 12, it is possible to detect that an excessive load or impact is applied by detecting the torque. .

Further, a flange may be provided on the shaft 10, and a fixed portion may be provided on the flange surface via a gap satisfying the above-described conditions.

In the first embodiment, the case where the ball bearings 11A and 11B are provided as the rolling bearings has been described. However, the present invention is not limited to this, and the rolling elements may be cylindrical rollers, tapered rollers, bar rollers, and needle rollers. Of course, various rolling bearings using spherical rollers or the like can be used.

In the first embodiment, one rolling bearing (ball bearings 11A and 11A) is provided at each end of the shaft 10.
Although the case where 1B) is provided has been described, the present invention is not limited to this, and a plurality of rolling bearings may be provided. (Embodiment 2) Next, a rotation shaft support mechanism according to Embodiment 2 of the present invention will be described with reference to the drawings.

FIG. 2 is a sectional view showing a rotary shaft support structure according to a second embodiment of the present invention. Embodiment 2
Then, members similar to those described in Embodiment 1 include:
The same reference numerals are given and the detailed description is omitted.

A rotating shaft support structure according to the second embodiment,
A different point of the rotating shaft support structure according to the first embodiment is that a corrugated washer 21 is interposed between the ball bearing 11A and the fixed portion 12. Specifically, as shown in FIG.
A corrugated washer 21 as an elastic member is disposed between the outer ring 15A of 1A and the fixed portion 12, and a preload is applied to the outer ring 15A by the corrugated washer 21.

In the second embodiment, similarly to the first embodiment, a gap C formed between one end face 10A of the shaft 10 and the fixed portion 12 causes an excessive axial load on the shaft 10. When an impact or the like is applied, the shaft 10
Is designed to be smaller than the displacement distance. Further, the gap C is set smaller than the shrinkage allowance of the wave washer 21.

In this structure for supporting a rotating shaft, an excessive axial load or impact is applied to the end face 10B of the shaft 10. When the load or impact displaces the shaft 10 in this direction (indicated by an arrow in FIG. 2), first, The corrugated washer 21 is compressed and the shaft 10
End surface 10 </ b> A comes into contact with the fixing portion 12. Here, since the load and the impact are received by the fixing portion 12, the load and the impact applied to the ball bearing 11A can be reduced, and the settling of the corrugated washer 21 can be prevented. As a result, it is possible to prevent the ball bearing 11A from being broken and to apply an optimal preload to the outer ring 15A for a long period of time. In addition, since the selection of the ball bearings 11A and 11B can be performed based on a normal load, downsizing can be achieved.

Further, since the shaft 10 abuts on the fixing portion 12 and is locked, the displacement amount due to the load or impact can be reduced.

In the second embodiment, the case where the corrugated washer 21 is provided as the elastic member has been described. However, the present invention is not limited to this. For example, a coil spring, a disc-shaped washer, a plate spring, etc.
Various elastic members can be provided.

In the second embodiment, an elastic member (corrugated washer 2) is provided between the outer ring 15A of the ball bearing 11A and the fixed portion 12.
Although the case where 1) is provided has been described, the present invention is not limited to this, and the elastic member may be provided between the outer ring 15B of the ball bearing 11B and the housing 13. Further, a flange may be provided on the shaft 10 and an elastic member may be provided between the flange surface and the fixing portion 12 or the housing 13. (Embodiment 3) Next, a rotating shaft support mechanism according to Embodiment 3 of the present invention will be described with reference to the drawings.

FIG. 3 is a cross-sectional view showing a rotary shaft support structure according to Embodiment 3 of the present invention, FIG. 4 is a side view of the rotary shaft support structure shown in FIG. 3, and FIG. It is an enlarged side view of the rotating shaft shown. In the third embodiment, the same members as those described in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The rotating shaft support structure shown in FIGS. 3 to 5 has a structure in which the shaft 30 is rotatably supported by ball bearings 11A and 11B provided at both ends of the shaft 30.
The shaft 30 is hollow and has a female screw at the left end of the inner wall in FIG. In the hollow portion of the shaft 30, a linear motion member 33 having an external thread formed on the outer periphery thereof, which is screwed with the internal thread, is provided. That is, when the shaft 30 rotates, the translation member 33 constitutes a translation actuator that moves in the axial direction. The rotation member 33 is connected with a rotation stopper (not shown) in order to prevent the linear movement member 33 from rotating itself.

Further, a permanent magnet 31 is provided on the outer periphery of the shaft 30. Further, the housing 13 has an electromagnetic coil 32 disposed concentrically with the permanent magnet 31 with a certain gap from the permanent magnet 31. The permanent magnet and the electromagnetic coil 32 constitute a two-phase stepping motor having 50 rotor teeth.

One end surface 30A of the shaft 30 (the right end in FIG. 3).
On the side, the fixed portion 12 is provided with a predetermined gap C from the end face 30A.
Are arranged. The gap C is designed to be smaller than a distance at which the shaft 30 is displaced by an excessive axial load or impact when the shaft 30 is subjected to an excessive load or impact.

As shown in FIG. 5, radially unevenness 35 is formed on the end face 30A of the shaft 30 at a pitch of about 1.8 degrees. In addition, the fixed portion 12 facing the end face 30A is also formed with unevenness 36 that can be fitted with the unevenness 35.
The unevenness 35 and the unevenness 36 are adjusted so as to fit at an angular phase at which the shaft 30 stops due to the magnetic force of the permanent magnet 31 when the two-phase stepping motor is not excited. In other words, when the two-phase stepping motor is not energized, if an excessive axial load or impact is applied to the shaft 30, the unevenness 35 and the unevenness 36 are fitted to prevent the shaft 30 from rotating. It has become.

On the other hand, if an excessive axial load or impact is applied to the shaft 30 while the two-phase stepping motor is energized, the unevenness 35 and the unevenness 36 depend on the energized state of the electromagnetic coil 32 of each phase. May not be in phase. In this case, the shaft 30 rotates until the phase where the unevenness 35 and the unevenness 36 are fitted by the load or the impact. However, since the pitch of the unevenness 35 and 36 is about 1.8 degrees, the angle of rotation is half of that. 0.9 degrees or less.
For this reason, there is no possibility that the two-phase stepping motor will lose synchronism, and the original angle can be restored if the load or impact is removed.

Further, the surface on which the irregularities 35 are formed and the irregularities 3
An electrical contact is formed on the surface on which 6 is formed, and by detecting the conduction state of the signal lines 37 and 38 connected to each of them, it is possible to detect that an excessive load or impact has been received.

The ball bearing 11 of the outer ring 15B of the ball bearing 11B
A wavy washer 21 is disposed between the A side and the housing 13. The outer ring 15B is preloaded by the corrugated washer 21.

In this structure for supporting the rotating shaft, an excessive axial load or impact is applied to the shaft 30 or the linear motion member 33. When the load or impact displaces the shaft 30 in this axial direction, first, the corrugated washer 21 is moved. The shaft 10 is compressed, and the end face 10 </ b> A of the shaft 10 abuts on the fixing portion 12. At this time, if power is not supplied to the two-phase stepping motor, the irregularities 35
And the unevenness 36 are fitted to prevent rotation of the shaft 30, so that the load against the shaft 30 while the shaft 30 is stopped or a shock can improve the resistance to the rotational force (torque) that attempts to rotate the shaft. On the other hand, when power is supplied to the two-phase stepping motor (that is, when the shaft 30 is rotating), after the shaft 30 rotates to a phase where the unevenness 35 and the unevenness 36 are fitted by the load or the impact, Asperity 35 and Asperity 3
6 are fitted to prevent the shaft 30 from rotating. Here, unevenness 3
Since the pitch of 5 and 36 is about 1.8 degrees, the angle of rotation is less than half that of 0.9 degrees, and there is no possibility that the two-phase stepping motor will lose synchronism.

When the bumps 35 contact the bumps 36, the signal lines 37 and 38 are energized, and it is detected that an excessive load is applied.

Since the load and the impact are received by the fixing portion 12, the load and the impact on the ball bearing 11A can be reduced, and the settling of the corrugated washer 21 can be prevented. As a result, the ball bearing 11A
Can be prevented from being destroyed, and the outer race 1
5A can be given an optimal preload over a long period of time. In addition, since the selection of the ball bearings 11A and 11B can be performed based on a normal load, downsizing can be achieved.

Further, since the shaft 30 abuts on the fixed portion 12 and is locked, the displacement amount due to the load or impact can be reduced.

In the third embodiment, the shaft 30 is formed hollow, a female screw is formed on the inner wall of the shaft 30, and a linear motion member formed with a male screw to be screwed to the female screw is used as the linear portion of the shaft 30. However, the present invention is not limited to this, and it is needless to say that a male screw may be formed on the outer periphery of the shaft 30 and a linear motion member having a female screw screwed to the male screw may be provided.

In the above-described embodiment, an example of a two-phase stepping motor having 50 rotor teeth has been described. However, the present invention is not limited to this and can be applied to other stepping motors and other motors. In this case, the pitch of the irregularities 35 and 36 may be changed to an appropriate value determined by a combination of the number of rotor teeth and the number of phases. (Embodiment 4) Next, a rotating shaft support mechanism according to Embodiment 24 of the present invention will be described with reference to the drawings.

FIG. 6 is a cross-sectional view showing a rotary shaft support structure according to Embodiment 4 of the present invention. FIG. 7A is an enlarged view of a flange surface of the rotary shaft shown in FIG. 6, and FIG. ) Is a further enlarged view. In the fourth embodiment, the same members as those described in the above embodiment are denoted by the same reference numerals, and the detailed description thereof will be omitted.

A support structure for a rotating shaft according to the fourth embodiment,
The different point of the rotation shaft support structure according to the third embodiment is that a shaft 41 is provided with a flange 41 and a sensor 42 for detecting the unevenness 35 provided on the flange 41 is provided.

Specifically, a flange 41 is provided at one end of the shaft 30. On the end surface (flange surface) 41A of the flange 41, irregularities 35 are formed. The fixing portion 12 is disposed on the flange surface 41A side with a predetermined gap C from the flange surface 41A. The gap C is designed to be smaller than a distance at which the shaft 30 is displaced by an excessive axial load or impact when the shaft 30 is subjected to an excessive load or impact.

The sensor 42 is disposed at a position capable of facing the unevenness 35 formed on the flange surface 41A, and outputs the rotation angle of the shaft 30 by detecting the unevenness 35. .

Although FIGS. 7A and 7B show the case where one sensor 42 is provided, the rotation of the shaft 30 when the two-phase stepping motor is not energized is detected. In this case, as described in the third embodiment, the shaft 3
Since the angular phase at which 0 stops is limited, it is not necessary to consider that the sensor 42 stops at the boundary where the sensor 42 is turned on / off. Therefore, as shown in FIGS. 30 rotation angles can be detected.

FIGS. 8A and 8B show two sensors 4.
2 are mounted in such a manner that they are shifted by a quarter of the pitch angle of the unevenness 35 formed on the flange surface 41A (ie, about 0.45 degrees). In this configuration, the shaft 30
Can be detected by the phase of the output signal of the two-phase stepping motor, so that the rotation of the shaft 30 can be detected both when the two-phase stepping motor is energized and when it is not energized.

The unevenness 3 formed on the flange surface 41A
5 can also be comprised from a through-hole.

The operation and effects of the rotary shaft supporting structure according to the fourth embodiment are the same as those of the third embodiment except that the rotation of the shaft 30 is detected by the sensor 42.

In the third and fourth embodiments, the example of the linear actuator for converting the rotary motion into the linear motion has been described. However, in the present invention, the rotary actuator (in the configuration of the first or second embodiment, the housing side is used). A motor having a stator and a rotor on the shaft side).

[0056]

As described above, in the rotary shaft support structure according to the present invention, the gap formed between at least one end surface of the shaft or the flange surface provided on the shaft and the fixing portion is defined by the above-mentioned structure. When an excessive axial load, impact, or the like is applied to the shaft, the shaft is formed so as to be smaller than the distance at which the shaft is displaced. The flange surface can be brought into contact with the fixing portion. Therefore, the load and the impact can be received by the fixed portion, and the load and the impact applied to the rolling bearing can be reduced. Further, since the shaft is locked by contacting the fixed portion,
The amount of displacement of the shaft due to the load or impact can also be limited. Furthermore, since the rotational frictional force of the shaft increases when the end surface or the flange surface of the shaft comes into contact with the fixed portion, it is possible to detect that an excessive load or impact is applied by detecting the torque. it can.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a support structure for a rotating shaft according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view showing a support structure for a rotating shaft according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a support structure for a rotating shaft according to a third embodiment of the present invention.

FIG. 4 is a side view of the shaft support structure shown in FIG. 3;

FIG. 5 is an enlarged side view of the shaft shown in FIG. 3;

FIG. 6 is a cross-sectional view illustrating a support structure for a rotating shaft according to a fourth embodiment of the present invention.

FIG. 7A is an enlarged view of a flange surface of the shaft shown in FIG. 6; FIG. 7B is a partially enlarged view of FIG. 7A.

FIG. 8A is an enlarged view showing another aspect of the flange surface of the shaft shown in FIG. 6; FIG. 8B is a partially enlarged view of FIG.

[Explanation of symbols]

 10, 30 Shaft 10A, 10B End face 11A, 11B Ball bearing 12 Fixed part 13 Housing 21 Wave washer 31 Permanent magnet 32 Electromagnetic coil 33 Linear member 35, 36 Irregularity 41 Flange 41A Flange surface

Claims (2)

[Claims] 1. A rotating shaft support structure for rotatably supporting a shaft via a rolling bearing, wherein the rotating shaft is provided with a gap to at least one end surface of the shaft or a flange surface provided on the shaft. With a fixed part,
The support structure for a rotating shaft, wherein the gap is formed to be smaller than a distance at which the shaft is displaced when an excessive axial load is applied to the shaft. 2. The apparatus according to claim 1, further comprising: a magnet provided on an outer periphery of the shaft; and an electromagnetic coil provided concentrically with the magnet on the fixed portion, wherein the magnet and the electromagnetic coil constitute an electromagnetic motor. 2. The support structure for a rotating shaft according to 1.