JP3143604B2 - Circulation path structure of rolling element in linear motion rolling bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a circulating path of a rolling element in a linear rolling bearing widely applied in the machine, semiconductor and automation industries.

[0002]

2. Description of the Related Art In a conventional linear motion linear rolling bearing, a circulating path structure of a rolling element merely focuses on a rotating effect of the rolling element.
In each case, a technique of contacting a curve is applied, and a straight line, an arc, an elliptical arc, or the like is touched. In general, a feature point is maintained at the same gradient. The disadvantage, however, is that the curvature at the point of contact with the path is discontinuous, resulting in an instantaneous sudden change in the centripetal acceleration. In high-speed motion, impact, vibration, sliding friction or impact on the rotating path cannot be avoided.

[0003] For example, FIG.
As described in Japanese Patent Publication No. 09820, the rotation path 1 has an arc shape with a radius R, and is tangent to both straight paths. When the rolling element 2 enters the semi-circular rotary path 1 from the linear load path 3, the curvature is 0 to 1/1 at the connection point B.
In the case where the curvature is rapidly increased to R, and conversely, when the distance from the rotation path 1 on the semicircular arc is increased, the curvature is sharply reduced from 1 / R to 0 at the connection point C. The design of the rotation path in the linear motion rolling bearing is described in Japanese Patent Application Laid-Open No. 60-143224 as shown in FIG. Is connected to a straight line. Their common feature was that they were tangent to and connected to the slope of each connection point by a curve, but because the curvature could not be connected, the impact, vibration, and noise due to the curvature discontinuity as described above However, drawbacks such as sliding friction or impact on a bent portion of the rotation path occur.
The corresponding positional relationship between the curvature and the length of the arc is shown in FIG. 21 and FIG.

A new improvement method for the above problem is disclosed in Japanese Patent Application Laid-Open No. Sho 62 (1987) shown in FIGS.
As can be seen from -492, the patent connects two or more curves with different curvatures to each other, from a curve with a smaller curvature to a curve with a larger curvature. However, when connecting the curves having the two different curvatures, the curvature continuity of the curves cannot be achieved even if the difference in the curvature when connecting the curves is reduced.
As shown in FIG. 28, the same patent uses a design that connects elliptical arcs instead of arcs. Since the curvature difference between the curved connection points was slightly reduced, the problem caused by the excessive curvature difference near those connection points was slightly improved. However, discontinuous curvature cannot effectively reduce noise due to sliding frictional resistance or vibration. The positional relationship corresponding to the curvature and the length of the arc is shown in FIG.

[0005] Linear motion rolling bearings are of the type linear guideway, linear ball bush, ball spline.
line) is widely applied in the machinery, semiconductor and automation industries, and further improvement of production efficiency of various production facilities is required one after another. Therefore, the motion speed for linear motion rolling bearings is correspondingly improved. Has been
Further, in the state where the above is applied to high speed, the problem of frictional resistance or noise caused by sliding of the rolling element in the rotation path is more serious problem.

However, the conventional structure of the rotation path of the rolling element in the linear motion rolling axis merely focuses on the connection of the tangent gradient, and each of them has a tangent of a straight line, an arc or an elliptic arc. At the connection point, even if the connection points can be connected at a tangent gradient to each other, the curvature on the left and right sides of the connection point cannot be realized as a continuous change, so when the rolling body enters the vicinity of the connection point of the circular arc path from the straight line, the curvature suddenly By increasing, the rolling body is rapidly rotated, and the centripetal acceleration suddenly appears. On the other hand, if the pressure at the bent portion of the rotation path is increased, the sliding frictional resistance is also increased. And
Because the curvature near the connection point became discontinuous, when the rolling bodies passed over to the above-mentioned part, they would easily collide with each other when they bounced, so that they could not operate smoothly, and furthermore, noise was generated and the transmission efficiency of the machine gradually increased It was to be reduced.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to secure the continuity of the tangent gradient of each contact point by connecting line steps such as curves, straight lines or circular arcs, and furthermore, to continuously change the curvature of the entire path. Can be maintained, thereby avoiding sudden changes in the centripetal acceleration, and by reducing its sliding friction,
Linear motion rolling, which can achieve high speed and effective linear motion because the rolling body can smoothly circulate, and also can reduce the noise caused by the rolling body's impact force, sliding friction or vibration on the rotation path An object of the present invention is to provide a circulation path structure for a rolling element in a bearing.

[0008]

In the linear rolling bearing according to the present invention, the structure of the circulating path of the rolling element is such that the rolling element is guided from the linear load path by rotating paths connected to each other, and rotates to rotate in a non-linear load path. After being connected to the other side, it is rotated to enter the linear load path, forming an infinite circulation circuit. The rotation paths on both sides of this circuit have one or more rolling centers of the rolling elements. In the structure of the circulation path of the rolling element in the linear rolling bearing consisting of a specific curve of the plane or space,
In order to maintain the gradient and the curvature of each point in the entire circulation path in a continuous manner, the structure of the circulation path solves the above-mentioned problem by matching the gradient and the curvature of the line step ends on both sides of each connection point. Solved.

In the linear rolling bearing of the present invention, the structure of the circulating path of the rolling element may be such that the curvature change of the curve of the function in the specific curve of the plane or space is defined as a continuous change from 0 to an arbitrary value, In addition, the specific curve of the space includes a curve of a tertiary space formed by intersecting the two arbitrary extended curved surfaces, and the extended curved surface is a curved surface extended from a normal direction of a plane where the specific curve of the plane is located. Further, the rotation path may be a continuous curvature path that is a combination of the specific curve and a linear step, an arc step, an elliptical step, or another curved step.

Accordingly, the structure of the circulating path of the rolling element in the linear rolling bearing of the present invention is such that the circulating path closed by the linear load path, the non-linear load path, and the two-stage rotary path connecting the two path line stages. By forming the path, the rolling element can perform an infinite circular rolling motion in this circulation path. In the design of the rotation path, the linear load path and the non-linear load path are connected with the curvature as a main design parameter. Therefore, the curvature of the curve is 0
From the arbitrary set value to the arbitrary set value, or it can be decreased from the arbitrary set value to 0. Therefore, the gradient of the cut line near the connection point is continuously maintained, and further,
Importantly, a continuous change in the curvature of the entire path can be maintained. Due to the characteristic of the curvature change of the path, a sudden change in the centripetal acceleration when the rolling element enters the rotation path from the connection path is removed, and the rolling element further reduces noise due to impact force, sliding friction or vibration on the rotation path. be able to.

A linear path and a non-linear load path are connected by using a rotation path constituted by a plane or space-specific curve, and the plane or space-specific curve is such that the curve of the function changes from zero to zero. It is defined that it can continuously change to the specified value. Using this characteristic, the curve,
By connecting line steps such as straight lines or circular arcs, continuity of the tangent gradient of each contact point can be ensured, and furthermore, the continuous change of curvature in the entire path can be maintained, thereby avoiding sudden changes in centripetal acceleration. It is possible,
Then, by reducing the sliding friction, the circulation of the rolling element can be smoothly performed, so that a high-speed and effective linear motion can be realized.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. The features and technical contents of the present invention can be further understood. However, the scheme of the present invention is used merely for reference or explanation, and There is no limitation on the invention.

FIGS. 1 to 19 show a specific embodiment of the rolling element rotation path of the linear rolling bearing according to the present invention, and FIGS.
To FIG. 29 show a conventional rotation path.

In the design of the circulation path in the conventional linear rolling bearing, a technique of tangent to a curve is often used in order to realize a smooth motion of the rolling element at a connection point portion of the rotation path. Then, by forming a circulation path of the rolling element which is closed by connecting an arc, an elliptic arc, a straight step, or the like, a tangent gradient of a connection point of each curve can be continuously maintained. Thereby, the degree of smoothness when the rolling body rotates is improved. However, in the application of the tangent technique to the curve as described above, the tangent gradient of the connection point of each curve can be kept continuous, but since the curvature near the connection point is not continuous, the rolling element is centriped when rotating. This leads to a rapid change in acceleration, and therefore, an enormous impact force is generated at the point where this rolling body bends, and furthermore, sliding friction also occurs on the rotating wall and the rolling bodies impact each other, resulting in lower transmission efficiency of the machine, Loud noise is also brought.

In order to overcome various problems caused by the sudden increase of the centripetal acceleration, the connection technique of the wire stage described in the present invention not only has a role of making the tangent gradient of each connection point continuous, but also has an The curvature of the circulation path can be continuously maintained. In the above-mentioned design, the centripetal acceleration of the rolling body increases in order from 0 when rotating, and when rotating the rolling body, not only does not produce a strong impact on the rotating wall, but also its sliding friction and vibration. Alternatively, the noise generated by the collision of the rolling elements with each other can also be reduced.

The point that the conventional curvature change directly affects the centripetal acceleration when the object rotates is clarified by the following description.

[0017] The mathematical formula for centripetal acceleration a _n are as follows.

(Equation 1) Here, V is defined as the linear velocity of the motion point, r is defined as the radius of curvature of the position of the motion point on the path, and the curvature of the arc is defined as 1 / r.

In the connection state of the rotation path 1 designed by the conventional arc tangent technique, as shown in FIG. 20, A is a connection point, and the curvature when the rolling element 2 performs linear motion is 0, the acceleration a _n is 0. But the moment the expiration of the connection point, the centripetal acceleration a _n is surged V ² / R, the size is the curvature directly proportional. Rotation curve 1 of the present embodiment
Is an arc shape, and its radius R is set to a fixed value, so that the change of the centripetal acceleration increases rapidly from 0 to a certain fixed value, so that the centripetal acceleration at the connection point due to the discontinuity of the curvature of the connection point B is changed. In addition to a sudden change, the direction of acceleration changes suddenly at the connection point B. The connection method of the curve as described above cannot avoid the bouncing of the rolling body or the impact on the rotating wall.

FIG. 1 shows a connecting portion of a path designed by applying the connecting technique of the present invention. When the rolling body 2 passes through the point A, its curvature continuously increases from 0 to 1/1 of the point P. r
_It increases to _p and further increases to 1 / r _{Q of the} Q point. Its centripetal acceleration also, V ² in the order from 0 at the same time / r _p and V
It is increased to ² / r _Q. By maintaining a continuous change in the centripetal acceleration in all paths, the rolling body 2 can reduce the impact or bouncing at continuous points.

In the design of the circulation path of the present invention, the curvature is the main design parameter. To meet the design principles of the present invention, a planar or space specific curve, such as a Cornu or Clothoid or a Bezier curve
rve) or other characteristic curves can also be applied. The Cornu helix is a function of the length of the arc, which is convenient to explain. In order to make the content of the present invention more understandable, a detailed description will be given below using a design example of the Cornu helix.

The standard Cornu helix applied here is expressed by the following equation.

(Equation 2) Where (X ₀ (u), Y ₀ (u)): the origin of the spiral, (X (u),
Y (u)): spiral point, h: proportional constant, u: length of spiral arc from starting point to (X (u), Y (u)) point, f (u):
The tangent function, whose mathematical meaning is spiral (X (u), Y
(u)) represents a section angle at the point.

The line function f (u) of the above-mentioned Corneus spiral
It is set to ^{f (u) = πu 2/} 2. From the above equation, the following curvature function of the Corneux spiral is obtained. c (u) = πu / h

As described above, the spiral curve has an arc length of 0.
Is obtained by increasing linearly from

FIG. 2 shows a design example in which the Cornu helix is applied to the rotation path of the present invention. The rotation path 1 is composed of bisymmetrical Cornu helix a and b, and the starting point of one helix is shown in FIG. While connected to the linear load path 3, it is connected to the non-linear load path 4 at one spiral starting point. Then, the cutting angle of the connection point of each line is continuously maintained, and the curvature of the rotation path 1 changes from 0 according to the length of the arc. The relative positional relationship between the curvature and the arc length is shown in FIG. In the diagram, the curvature of the rotation path 1 increases in order from 0 from the starting point B to the intersection of both the above-mentioned Cornu spirals, then decreases gradually, and becomes 0 when reaching the end point D of the path. Since the curvature of the path can be changed continuously, it is possible to avoid the drawback of a sudden change in acceleration in the conventional design.

FIGS. 4 to 12 show other examples of the application of the Cornu helix applied to the rotation path according to the present invention, wherein the path shown in FIG. 4 is composed of four Cornu helixes a, b, c and d. The path shown in FIG. 6 is composed of four Corne spirals a, b, c, d and one straight step c. In both of the above-mentioned applications, both the cutting angle and the curvature of each contact point are continuous. Can be maintained.

In the design of the rotation path as described above, the curvature function is linear, that is, any curvature changes linearly according to the length of the arc, but the curvature function is linear, sine function, quadratic or higher. It can be defined from a polynomial.

As an example of a quadratic polynomial, by setting the curvature function as C (u) = 6πu (1-u), the curve (X (u), Y (u)) becomes
It can be expressed by the following equation.

(Equation 3)

If the integral upper limit of the length of the arc is set to 1, the change curvature along the helical spiral and the arc length is shown in FIG.

As an example of a sine function, its curvature function can be set to C (u) = πsin (2u).

The curve (X (u), Y (u)) is represented by the following equation.

(Equation 4)

When the upper limit of the integral of the arc length u is set to π / 2, the curvature changing along the Corne spiral and the arc length is shown in FIG.

The above is an application example of the Cornu helix used in the design of the plane rotation path of the present invention. In the present invention, this helix is further applied to the design of the rotation path in a three-dimensional space. The spatial rotation path in the design method is obtained by intersecting two Cornu curved surfaces. Here, the Cornu curved surface is a curved surface that is extended along the normal direction where the plane rotation path composed of the Cornu helix is located.

FIG. 12 shows a specific application example of the above-mentioned design method, in which the spatial rotation path intersects two Cornu curved surfaces. The above-mentioned Cornu curved surface is a curved surface formed by extending a plane rotation path composed of a Corneux spiral along its normal direction. These two plane paths are connected to both ends of the linear load path and the non-linear load path, one plane is connected to the planes of the two linear paths, and the other plane is formed perpendicular to the plane. Is done.

Another method of the Cornu helix applied to the rotation path in the three-dimensional space is to draw a cylindrical surface having a specified radius, for example, by making the plane Cornu helix follow a special-point surface. This method can be applied to the design of a rolling circulation path of a linear ball bush as shown in FIG. In the application example of the above part, a complete description is described in a specific embodiment described later.

As a specific application example of product design, the design of the present invention is also applicable to the design of the present invention by changing a straight step, an arc step, an elliptical step, or another curved step by connecting the curve to the actual product. To match. However, the continuity of the curvature cannot be maintained unless the curvature is always the same on both the left and right sides of the connection point. For example, in the case of connecting in a straight line step, the curvature at the connection point between both ends of the straight line and the Corneux spiral is zero.

FIG. 13 shows an embodiment of a design applied to a linear ball bush in the present invention. The circulation path of this product must be formed on a cylindrical surface of a specified radius because it matches the characteristics of the product. The means applied to the present design example is to create a plane Cornu spiral by drawing a cylindrical surface of a specified radius, and further connect the linear load path and the non-linear load path as shown in FIG. Continuity of curvature is achieved. Detailed means are described as follows.

The radius of the column surface is R, and the plane axis Y is curved along an arc. x = X θ = Y / R

This spatial Cornu spiral (X (u), Y (u), Z
(u)) is expressed as follows.

(Equation 5)

The length of the arc of the corrected curve is the original u, but its curvature function is

(Equation 6) Becomes

From the above equation, the curvature of the Cornu helix drawn along the cylindrical surface slightly changed from that of the original plane Cornu helix, but the new curvature function has a curvature from zero to a continuous curvature. The change characteristics are maintained.

The above is an embodiment in which the present invention is applied to the design of the rotation path of the linear ball bush. The point that the design should be focused on most is that the curvature of the applied Cornu helix ranges from 0 to an arbitrary designated value. Up to a point of continuous change,
By connecting the linear load and the non-linear load, the rotation of the rolling body can be further smoothly performed.

The curve in which the curvature is continuously changed from 0 to an arbitrary designated value includes, for example, a Bezier curve in addition to a Corneux spiral. The following embodiment is a five-stage Bezier curve applied to the present invention shown in FIG. 15, and is a design example of a rotation path in a rolling linear rail. The rotation path N in FIG. 16 is a rotation path designed by a traditional method, and this curve is composed of two semicircular arcs tangent to a linear load path and a non-linear load path. The line created by intersecting the curved surface extending along the normal of the plane in which it lies is maintained tangent to this curve and to the linear and non-linear load paths, i.e. its cut slope. Can be maintained continuously. From a geometric point of view, when passing through a connection point, the movement cannot smoothly move like this rotation path. As can be seen from FIG. 17, the change in the curvature of this rotation path is directly from 0 at the connection point to 0.
Due to the jump to 168, the problem caused by the curvature discontinuity cannot be avoided.

The rotation path B shown in FIG. 18 is the design principle of the present invention, and as can be seen from FIG. 19, the rotation path designed by applying the Vegir curve is the connection point between this rotation path 1 and both linear paths. Since the gradient and curvature on the left and right sides of B and F are the same, the gradient or curvature at each point in the general circulation path can be maintained in a continuous change. As a result, a rapid change in the centripetal acceleration at the connection point can be avoided, and by further reducing sliding friction and noise, the circulation of the rolling element can be further smoothly performed, and the required high speed and efficient linear motion can be achieved. Is achieved.

The main aim of the present invention is to maintain the continuity of the curvature of the overall circulation path, and to modify certain parts, such as straightening of linear rails, for processing or mounting, etc. in practical product applications. Chamfer or R at both ends of step
Increasing the countersink or the like required for cornering or assembling all belongs to the application of the present invention.

In addition to the above embodiments, the present invention is applied to other linear motion parts such as linear rails, linear ball bushes, and rolling body circulation paths such as ball splines and linear transfer tables. Can also consist of balls, rollers or other rolling elements.

The specific embodiments described above are used to explain the objects, features and effects of the present invention in detail, and those skilled in the art in this area will appreciate the specific implementation based on the above description. Since the examples can be partially changed or modified without departing from the spirit of the present invention, the claims of the present application are limited by the claims attached to the description.

[Brief description of the drawings]

FIG. 1 is a sketch of a rotation path and a curvature distribution of a curve according to the present invention.

FIG. 2 is a schematic view of a rotation path of the present invention composed of a Corneux spiral.

FIG. 3 is a relationship diagram showing a curvature of a rotation path of FIG. 2 and a relative position thereof.

FIG. 4 is a sketch of the improved Cornu helix structure shown in FIG. 2;

FIG. 5 is a relationship diagram showing the curvature of the rotation path in FIG. 4 and its relative position.

FIG. 6 is a sketch of another modified Cornu helix structure shown in FIG. 2;

FIG. 7 is a relationship diagram showing the curvature of the rotation path in FIG. 6 and its relative position.

8 is a perspective view of another modified Cornu helix structure shown in FIG. 2. FIG.

9 is a relationship diagram showing the curvature of the rotation path in FIG. 8 and its relative position.

10 is a perspective view of another modified Cornu helix structure shown in FIG. 2. FIG.

11 is a relationship diagram showing the curvature of the rotation path in FIG. 10 and its relative position.

FIG. 12 is a diagram showing a curve formed by intersecting a Cornu curved surface in a space.

FIG. 13 is a diagram for explaining the design of the ball circulation path of the linear ball bush.

FIG. 14 is a diagram showing a Cornu curve in cylindrical coordinates.

FIG. 15 is a diagram for explaining the design of the rotation path of the ball linear rail.

FIG. 16 is a diagram showing a comparison between the present invention and a spatial rotation path of a traditional method.

FIG. 17 is a relationship diagram showing the curvature of the rotation path in FIG. 16 and its relative position.

FIG. 18 is a sketch of a rotation path of the present invention composed of a Vegir curve.

19 is a relationship diagram showing the curvature of the rotation path in FIG. 18 and its relative position.

FIG. 20 is a sketch of a conventional rotation path formed from a semicircular curve.

21 is a relationship diagram showing the curvature of the rotation path in FIG. 20 and its relative position.

FIG. 22 is a schematic view of a conventional rotation path formed by connecting straight steps between two quarter arcs.

23 is a relationship diagram showing the curvature of the rotation path in FIG. 22 and its relative position.

FIG. 24 is a sketch of a conventional rotation path composed of three arcs.

25 is a relationship diagram showing the curvature of the rotation path in FIG. 24 and its relative position.

FIG. 26 is a sketch of a conventional rotation path composed of five arcs.

FIG. 27 is a relationship diagram showing the curvature of the rotation path in FIG. 26 and its relative position.

FIG. 28 is a schematic view of a conventional rotation path formed by connecting straight steps between two quarter arcs.

FIG. 29 is a relationship diagram showing the curvature of the rotation path in FIG. 28 and its relative position.

[Explanation of symbols]

 Reference Signs List 1 rotation path 2 rolling element 3 linear load path 4 non-linear load path

Continuation of the front page (56) References JP-A-55-109820 (JP, A) JP-A-60-143224 (JP, A) JP-A-62-24922 (JP, A) JP-A-62-256619 (JP) U.S. Pat. No. 5,649,770 (US, A) U.S. Pat. No. 4,795,272 (US, A) U.S. Pat. No. 5,909,965 (US, A) German Patent Application Publication No. 19714414 (DE, A1) (58) Field of Study (Int. Cl. ⁷ , DB name) F16C 29/06

Claims (4)

(57) [Claims] 1. A rolling element is guided from a linear load path by a rotational path connected to each other, rotates, is connected to a non-linear load path, and is connected to the other side.
Rotation into the linear load path, forming an infinite circulation circuit, the rotation path on both sides of this circuit is a linear rolling bearing in which the rolling center of the rolling body consists of one or more specific curves of a plane or space In the structure of the circulation path of the rolling element, the structure of the circulation path is designed to maintain the gradient and curvature of each point in the entire circulation path in a continuous manner. A structure of a circulating path of a rolling element in a linear rolling bearing, wherein curvatures are matched. 2. The linear rolling bearing according to claim 1, wherein the curvature change of the curve of the function in the specific curve of the plane or the space is defined as a continuous change from 0 to an arbitrary value. The structure of the circuit. 3. The specific curve of the space includes a curve of a cubic space formed by intersecting both arbitrary extension curved surfaces, and the extended curved surface extends from a normal direction of a plane where the specific curve of the plane is located. The structure of a circulation path of a rolling element in a linear rolling bearing according to claim 1, wherein the curved surface is a curved surface. 4. The linear rolling device according to claim 1, wherein the rotation path includes a curvature continuous closed path formed by combining the specific curve with a linear step, an arc step, an elliptical step, or another curved step. The structure of the circulation path of the rolling element in the bearing.