JPH0518490Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a bearing mechanism configured to apply axial preload to a rolling bearing to remove backlash.

[Prior Art] As shown in Fig. 7, rolling bearings include cross roller bearings in which cylindrical rollers 1 are arranged between an inner ring 2 and an outer ring 3 so that their rotating axes alternate by 90 degrees. .

Conventionally, as a bearing mechanism using a cross roller bearing, there has been a structure shown in FIG. 8, for example.

In the figure, in the cross roller bearing, an inner ring 2 and an outer ring 3 are fitted into housings 4 and 5, respectively, and the housing 4 is rotatably supported by the housing 5. 6 and 7 are made of a steel material with much higher rigidity than roller 1, and are constructed in a circular ring shape, and tightening screws 8 and 9
This is a clamp assembled to housings 4 and 5 by. These clamps 6 and 7 apply an axial preload to the cross roller bearing by means of tightening screws 8 and 9, thereby removing play in the bearing.

The reason why the clamps 6 and 7 are made of a steel material that is much more rigid than the roller 1 is as follows.

The bearing mechanism shown in FIG. 8 applies preload by the axial force of tightening screws 8 and 9. Therefore, if the clamps 6 and 7 are made of steel material with lower rigidity than the roller 1, the tightening screw 8
and 9, the tightening screws 8 and 9 deform before the roller 1, and the preload cannot be controlled by the axial force of the tightening screws. From such a thing,
In the bearing mechanism shown in FIG. 8, the clamps 6 and 7 are made of a steel material that is much more rigid than the rollers 1.

[Problems to be solved by the invention] In such a bearing mechanism, the clamps 6 and 7 are
Since there is almost no deformation, the axial force of the tightening screws 8 and 9 becomes a preload on the bearing. Therefore, the preload is managed by the tightening torque of the screws 8 and 9.

However, it is difficult to adjust the tightening torque of screws.
It is difficult to apply a uniform preload over the entire circumference of the bearing.

Furthermore, the rigidity of the bearing mechanism is determined by the rigidity of the clamping screw, the rigidity of the clamp, and the rigidity of the bearing, so it is necessary to use a clamping screw with high rigidity and a large diameter. Using such a tightening screw reduces the number of screws required to obtain the desired preload. This also results in non-uniform preload being applied to the entire circumference of the bearing.

In this way, it has been difficult to realize a bearing mechanism that is both easy to adjust the preload and high rigidity.

The present invention was developed in consideration of these points, and it combines ease of preload adjustment and high rigidity.
Moreover, it is an object of the present invention to realize a bearing mechanism that can easily apply preload uniformly over the entire circumference of the bearing.

The present invention provides a bearing mechanism configured to apply an axial preload to a rolling bearing to remove backlash, in which an outer ring and an inner ring of the rolling bearing are fitted together, and the end face position of the bearing is located at the outer ring. and two housings located at a position lower than the end face position of the inner ring; and two housings made of an elastic material and configured in the shape of circular plates, which are respectively attached to the two housings and press down the end face portions of the outer ring and the inner ring. two clamps; a gap formed between the two housings and the clamps due to a height difference between the end face position of the housing and the end face positions of the outer ring and the inner ring; and a gap formed between the two clamps; a tightening screw that is screwed into a screw hole formed in each housing to fix the clamp to the housing; and a tightening force of the tightening screw deforms each clamp until the gap disappears. Through this deformation, the clamp holding down the end surface of the outer ring is transferred from a mechanical model of deformation of the circular plate supported on the outer periphery to a mechanical model of deformation of the circular plate fixed on the outer periphery, and the end surface of the inner ring is This bearing mechanism is characterized in that the clamp that is holding down the clamp is transferred from a mechanical model of deformation of a circular plate supported on the inner periphery to a mechanical model of deformation of a circular plate fixed on the inner periphery.

[Example] The present invention will be explained below with reference to the drawings.

FIG. 1 is a configuration diagram of an embodiment of a bearing mechanism according to the present invention. In the figure, the same parts as in FIG. 8 are given the same reference numerals.

When the cross roller is inserted into the housing, there is a height difference between the end face position of the cross roller and the end face position of the housing. Let this height difference be W.

The clamps 10 and 11 are made of a light alloy elastic material, such as aluminum, and have a ring shape. When placed on the end faces of the housings 4 and 5, there is a gap 12, 1
3 occurs. When the tightening screws 8, 9 are tightened, the clamps 10, 11 are deformed so that the intermediate portions 12, 13 are eliminated.

Next, a procedure for assembling the clamps 10 and 11 will be explained.

This will be explained using the clamp 11 as an example.

When the clamp 11 is placed on the end surface of the housing 5, the clamp 11 is in contact with the outer ring 3 of the bearing on the inner diameter side, but is in contact with the housing 5 on the outer diameter side.
It is suspended from the end surface of. When the tightening screw 9 is tightened in this state, the part of the clamp 11 which has become a circular plate becomes a free end, the part that is floating from the housing 5 becomes a supporting end, and the part that contacts the outer ring 3 becomes a supporting end. A load is applied by the tightening screw 9.

As the tightening screw 9 is tightened, the free end deforms, and eventually the outer periphery of the clamp 11 comes into contact with the end surface of the housing 5, and the clamp 1 is attached to the inner periphery of the clamp 11.
An elastic force caused by the deformation of 1 is added. As a result, the outer circumferential side of the clamp 11 becomes a supporting end, and the inner circumferential side becomes a free end. That is, the outer periphery of the clamp 11 that is in contact with the housing 5 serves as a supporting end, and the inner periphery that contacts the outer ring 3 serves as a free end, and the elastic force due to the deformation of the clamp 11 is applied to the free end. There is. Such a deformed state is defined as deformation of the circular plate supporting the outer periphery.

When the tightening screw 9 is further tightened, the spacer section 13
becomes smaller, the contact area between the clamp 11 and the housing 5 becomes larger, and the supporting end approaches the fixed end. Eventually, the outer periphery of the clamp 11 becomes a fixed end. As a result, the outer periphery of the clamp 11 becomes a fixed end, and the inner periphery becomes a free end, and a reaction force against the elastic force due to the deformation of the clamp 11 is applied to the free end. Such a deformed state is defined as deformation of the circular plate whose outer periphery is fixed.

Clamp 10 also undergoes the same deformation as clamp 11, although the outer and inner circumferences are reversed.

That is, the clamp 10 transitions from a mechanical model of deformation of an annular plate supported on the inner periphery to a mechanical model of deformation of an annular plate fixed on the inner periphery due to deformation.

Here, the above-mentioned deformation process will be mechanically explained.

In FIG. 3, the deflection w is given by the following equation.

w = α (Pa ² / Eh ³ ) (1) α: Deflection coefficient of circular plate, P: Load, a: Outer diameter of circular plate, h: Thickness of circular plate, E: Longitudinal elasticity of clamp Coefficient: Here, the deflection coefficient is α∝a/b, so w∝a ³ P/bh ³ (2). The ratio of deflection to load (hereinafter referred to as displacement rigidity) w/P is obtained from equation (2) as w/P∝a ³ /bh ³ (3), and displacement rigidity can be determined depending on the shape. Furthermore, by increasing the number of tightening screws, the displacement rigidity can be reduced. When the number of screws is n, the following relationship holds: w/P∝a ³ /bh ³ n (4).

Here, a mechanical model of deformation of the circular plate supported on the outer periphery is shown in FIG.

In this model, the displacement stiffness is given by the following equation:

w=α ₉ (Pa ² /Eh ³ ) (5) Furthermore, the mechanical model of deformation of a circular plate whose outer periphery is fixed is as shown in Fig. 3.

In this model, the displacement stiffness is given by the following equation:

w=α ₁₀ (Pa ² /Eh ³ ) (6) Here, the magnitudes of the deflection coefficients α ₉ and α ₁₀ of the circular plate are as shown in Figure 4.

As shown in the figure, the coefficient α ₉ is larger than α ₁₀ .
Therefore, when a preload is applied, the displacement rigidity, that is, the amount of deformation with respect to the load becomes larger. As a result, only a low load is required when preload is applied, and after the load is further increased and the clamp is assembled, the displacement rigidity is reduced, and the bearing is supported with high rigidity.

The relationship between displacement w and load P when preload is applied and after assembly is as shown in the graph of FIG.

In the figure, the range P ₁ is when preload is applied, and the range P ₂ is after assembly.

As shown in the graph of FIG. 5, in the P ₁ range, the displacement variation Δw is larger than the load variation ΔP, and in the P ₂ range, Δw is smaller than ΔP.

For this reason, when adjusting the load P within a certain range when applying preload, the adjustment range of the displacement w becomes wider. This makes it easy to adjust the preload. Further, after assembly, the fluctuation of the displacement w becomes smaller with respect to the fluctuation of the load P, so that the rigidity becomes higher.

These formulas are on page A4-55 of the Mechanical Engineering Handbook.
It is written on page A4-58.

From equation (4), the relationship between displacement rigidity w/P and a ³ /bh ³ n is graphed as shown in FIG.

As shown in this graph, when the number of tightening screws is increased (when n is increased), the displacement rigidity decreases and high rigidity is obtained. From this,
The larger the number of screws, the better. .

In addition, the constituent materials of the clamps 10 and 11 are as follows:
Materials other than aluminum may be used.

Further, as the bearing, a rolling bearing such as a ball bearing or a roller bearing other than a cross roller bearing may be used.

[effect] According to the present invention, the following effects can be obtained.

A clamp with low displacement rigidity (high rigidity) is achieved only after the clamp is assembled, so the step of applying preload only requires tightening the screw, and the process of finely adjusting the preload can be omitted. .

Even if a light metal with low rigidity such as aluminum is used, a highly rigid clamp can be achieved after assembly, so the mechanism can be made lighter.

As you tighten the tightening screw, clamp 1
1 transitions from a mechanical model of deformation of a circular plate supported on the outer periphery to a mechanical model of deformation of a circular plate fixed on the outer periphery. Therefore, the relationship between the displacement of the clamp and the load applied to the clamp is as shown in FIG. As a result, since the displacement rigidity is high at the stage of applying preload, when adjusting the load P within a certain range, the adjustment range of the displacement w becomes wider, so that adjustment of the preload becomes easier. After assembly, the displacement rigidity is reduced, so high rigidity can be obtained.

The clamp 10 exhibits similar characteristics, although the outer and inner circumferences are reversed.

For these reasons, it is possible to easily adjust the preload and obtain high rigidity.

Since the preload is not generated directly by the tightening force of the tightening screw as in the conventional example, but is generated by the deformation of the clamp, the preload can be applied uniformly over the entire circumference of the bearing.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the bearing mechanism according to the present invention, FIGS. 2 to 6 are explanatory diagrams of the assembly procedure of the clamp shown in FIG. 1, and FIG. 7 is a configuration diagram of a cross roller bearing. FIG. 8 is a diagram showing an example of the configuration of a conventional bearing mechanism. 1...Roller, 2...Inner ring, 3...Outer ring, 4,5
... Housing, 8, 9 ... Tightening screw, 10,
11... Clamp, 12, 13... Intersection.

Claims (1)

[Claims for Utility Model Registration] In a bearing mechanism configured to apply axial preload to a rolling bearing to remove backlash, an outer ring and an inner ring of the rolling bearing are fitted together, and the end face of the bearing Two housings are located at a position lower than the end faces of the outer ring and the inner ring, and the housing is made of an elastic material and is configured in the shape of a circular plate, and is attached to each of the two housings, and is attached to the end faces of the outer ring and the inner ring. The two clamps holding down the housing, and the gap formed between the two housings and the clamp due to the difference in height between the end face position of the housing and the end face positions of the outer ring and the inner ring, and a bottom part formed between the two clamps. a tightening screw that penetrates each clamp at a portion and is screwed into a screw hole formed in each housing to fix the clamp to the housing; The clamp is deformed, and through this deformation, the clamp holding down the end surface of the outer ring is transferred from a mechanical model of deformation of a circular plate supported on the outer periphery to a mechanical model of deformation of a circular plate fixed on the outer periphery. 1. A bearing mechanism characterized in that a clamp holding down an end face portion of the bearing mechanism transitions from a mechanical model of deformation of a circular plate supported on the inner periphery to a mechanical model of deformation of a circular plate fixed on the inner periphery.