JP2016217916A - Cloth roller bearing and method for measuring pre-load amount of cloth roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for quantitatively measuring the pre-load amount of a cloth roller bearing, and the cloth roller bearing capable of easily measuring the pre-load amount.SOLUTION: A method for measuring the pre-load amount of a cloth roller bearing comprises the steps of: measuring the frictional coefficient of a bolt 6 for tightening an outer ring presser 4; tightening the bolt 6 up to a target torque to apply a pre-load to the outer ring 2; placing a displacement meter at a predetermined position; loosening the bolt 6 until separated from a seating surface to measure a displacement amount generated from the initial state until the upward movement of the outer ring 2 is finished; and contacting the contact of the displacement meter with the upper surface of the outer ring 2 along three or more guide grooves 5 or holes to check the variation of a bearing space and quantify a relationship between an axial direction load generated in the outer ring presser 4 and the bearing space.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cross roller bearing and a preload measuring method for the cross roller bearing.

As shown in FIG. 17, the cross roller bearing rolls in 90-degree V-grooves (11) and (21) provided in the circumferential direction on the opposing surfaces of the inner ring (1) and the outer ring (2), respectively. A roller (cylindrical roller) (3) is provided. In the roller (cylindrical roller) (3), the corner (31) is chamfered with an arc having a small radius of curvature (r), and the V-groove (11) is provided. ) And (21) are disclosed in which the width (B) of the outer peripheral surface of the roller (cylindrical roller) (3) is longer than the width (b) of the rolling surfaces (12) and (22). (See Patent Document 1).

That is, the cross roller bearing is a bearing in which rollers (cylindrical rollers) (3) are alternately arranged in 90-degree V-grooves (11) and (21), and a single bearing adds a load in the radial direction and the thrust direction. It is possible to receive force from all directions such as moment. The biggest feature is very compact and high rigidity can be obtained, so it is often used in places where accuracy is required in joints of robots and machine tools.

Here, referring to Patent Document 2 (see FIG. 18), a preload is applied to a cross roller bearing (hereinafter simply referred to as “bearing”) (3) interposed between the rotating shaft (1) and the housing (2). The structure to be shown is shown. The inner ring (4) of the cross roller bearing (3) is externally fitted and fixed to the rotary shaft (1), and an inner ring presser (fixed to the end of the rotary shaft (1) via a fixing bolt (5). 6). Preloading means that the clearance of the bearing is eliminated as a negative clearance, and the rolling element is always in contact with the rolling surface in a deformed state. For this reason, the friction torque increases, which causes power loss. Currently, there is a demand for energy saving of machines, and reducing the friction torque of cross roller bearings is an important issue.

Referring to FIG. 18 again, the outer ring (7) is fitted and fixed to the housing (2). And a preload is applied to the bearing (3) by pressing the outer ring (7) in the axial direction by the outer ring presser (9) fastened and fixed to the end of the housing (2) via the fixing bolt (8). It is supposed to be.

According to Patent Document 2, the preload is applied and the clearance (C1) between the housing (2) and the outer ring presser (9) is set to an appropriate amount, and the clearance is tightened with the fixing bolt (8). (C1) is eliminated and a fixed position preload is applied to the bearing (3) by the clearance (C1), and the internal axial clearance (C2) of the bearing (3) is set to an appropriate amount, and the fixing bolt (8) It is said that there is a method of pre-loading the bearing (3) by eliminating the gap (C2) when tightened at. Thus, in order to make the cross roller bearing highly rigid and accurate, it is necessary to apply a preload. However, the set amount of the gap (C1) or the gap (C2) is a very delicate value. It was also very difficult. In particular, if the friction torque of the rotating shaft is set to a constant value, there is a problem that the setting of the amount of clearance (C1) or clearance (C2) and the work are difficult.

A cross roller bearing preload adjusting structure according to Patent Document 2 is a structure for adjusting a preload of a cross roller bearing that is interposed between a shaft and a housing so as to rotatably support the shaft, and is fixed to the housing. An outer ring presser that is fastened and fixed through the outer ring and presses the outer ring in the axial direction to apply a preload during the tightening, and can advance and retreat in the axial direction with respect to the outer ring presser and protrudes between the outer ring presser and the housing. And a screw member that is screwed in such a manner that a projecting end abuts against the housing at the time of tightening. That is, in addition to the fixing bolt, it is essential to provide a screw member whose protruding end abuts on the housing when tightening.

In one embodiment of Patent Document 2, in the conventional structure, the internal axial gap (C2) of the bearing (3) acts as a preload on the bearing (3) by the amount tightened by the fixing bolt (8). The amount is almost determined by the value of the clearance (C2), but the fixing bolt (8) is tightened with a set screw (12) arranged with a mounting pitch diameter smaller than the mounting pitch diameter of the fixing bolt (8). Therefore, the bearing (3) can be prevented from being subjected to a preload exceeding a certain level, and the protruding length of the set screw (12) can be continuously adjusted. The amount of preload acting on can be adjusted freely. As a result, for example, by adjusting the tightening torque of the fixing bolt (8) and the set screw (12) or adjusting the preload amount while inspecting the pushing amount of the outer ring retainer (10), It is said that the friction torque of 1) can always be kept at a stable value, and efficient torque can be transmitted.

Japanese Utility Model Publication No. 5-89956 JP-A-9-303385

When the preload is increased, the rigidity and accuracy are increased while the friction torque is increased. Therefore, it is necessary to know the preload amount and determine an appropriate preload amount. In the above-mentioned Patent Document 2, in addition to the fixing bolt, further tightening of the fixing bolt is regulated by providing a screw member whose protruding end comes into contact with the housing when tightening. However, Patent Document 2 does not disclose a quantitative measurement method of the preload amount of the cross roller bearing. An object of the present invention is to provide a method for quantitatively measuring the preload amount of a cross roller bearing and a cross roller bearing capable of easily measuring the amount of preload by the method of quantitatively measuring the preload amount of the cross roller bearing. It is what.

According to the first aspect of the present invention, there is provided a method for measuring a preload amount of a cross roller bearing in which a preload is applied to an outer ring by pressing a flange-shaped outer ring,
(A) A step of measuring a friction coefficient of a bolt for tightening the outer ring retainer using a jig manufactured in advance with the same material as the outer ring retainer,
(B) After the step (A), using a bolt of the same type as the bolt whose friction coefficient was measured in the step, a preload is applied to the cross roller bearing and a preload is applied to the outer ring in an initial state. The cross roller bearing is inserted into a cylindrical recess having a depth substantially equal to the thickness of the cross roller bearing. A step of placing an outer ring retainer on the outer ring of the roller bearing, and inserting the bolt into the outer ring retainer to determine the position of the outer ring retainer, tightening the bolt to the target torque, screwing it to the cylinder block, A step including a step of applying a preload;
(C) installing the displacement meter at a predetermined position;
(D) Adjust so as to be perpendicular to the cross roller bearing, loosen the bolt until it leaves the seating surface, and measure the amount of displacement that occurs between the initial state and the end of the upward movement of the outer ring. Three or more guide grooves or holes on the inner surface of the outer ring retainer along the axial direction of the cross roller bearing in order to guide the probe shaft having the displacement gauge contact at the tip. The probe shaft is lowered along the guide groove or hole, and the displacement gauge contact amount is checked against the upper surface of the outer ring to check the amount of change in the bearing clearance. The method includes the step of quantifying the relationship between the axial load and the bearing clearance.

According to a second aspect of the present invention, there is provided a cross roller bearing comprising cylindrical rollers that roll in 90-degree V grooves provided in the circumferential direction on opposite surfaces of the inner ring and the outer ring, respectively.
The outer ring is fitted into the housing;
A substantially annular outer ring presser that is fastened to the housing via a bolt and presses the outer ring in the axial direction to apply a preload;
It is characterized in that three or more guide grooves or holes for guiding a probe shaft having a contact of a displacement meter at the tip are formed on the inner surface of the outer ring retainer along the axial direction of the cross roller bearing.

According to the first aspect of the present invention, there is provided a method for measuring a preload amount of a cross roller bearing in which a preload is applied to an outer ring by pressing a flange-shaped outer ring,
(A) A step of measuring a friction coefficient of a bolt for tightening the outer ring retainer using a jig manufactured in advance with the same material as the outer ring retainer,
(B) After the step (A), using a bolt of the same type as the bolt whose friction coefficient was measured in the step, a preload is applied to the cross roller bearing and a preload is applied to the outer ring in an initial state. The cross roller bearing is inserted into a cylindrical recess having a depth substantially equal to the thickness of the cross roller bearing. A step of placing an outer ring retainer on the outer ring of the roller bearing, and inserting the bolt into the outer ring retainer to determine the position of the outer ring retainer, tightening the bolt to the target torque, screwing it to the cylinder block, A step including a step of applying a preload;
(C) installing the displacement meter at a predetermined position;
(D) Adjust so as to be perpendicular to the cross roller bearing, loosen the bolt until it leaves the seating surface, and measure the amount of displacement that occurs between the initial state and the end of the upward movement of the outer ring. 3 or more guide grooves or holes are formed in the inner surface of the outer ring retainer along the axial direction of the cross roller bearing in order to guide the probe shaft having the displacement gauge contact at the tip. Then, along the three or more guide grooves or holes formed, the probe shaft is lowered, the contact of the displacement meter is brought into contact with the upper surface of the outer ring, and the amount of change in the bearing clearance is confirmed, Cross roller, which has been difficult to perform quantitative measurement methods in the past because it has a structure that includes the process of quantifying the relationship between the axial load generated by the outer ring presser and the bearing clearance. It is possible to quantify the preload measuring method of bearings, it is possible to obtain an excellent effect of preload management of the cross roller bearing is facilitated.

According to a second aspect of the present invention, there is provided a cross roller bearing comprising cylindrical rollers that roll in 90-degree V grooves provided in the circumferential direction on opposite surfaces of the inner ring and the outer ring, respectively.
The outer ring is fitted into the housing;
A substantially annular outer ring presser that is fastened to the housing via a bolt and presses the outer ring in the axial direction to apply a preload;
It has a configuration in which three or more guide grooves or holes for guiding a probe shaft having a contact of a displacement meter at the tip are formed on the inner surface of the outer ring retainer along the axial direction of the cross roller bearing. Therefore, it is possible to provide a cross roller bearing capable of easily measuring the preload amount by the quantitative measurement method of the preload amount of the cross roller bearing according to the first aspect.

It is a section explanatory view showing an example of a cross roller bearing concerning one embodiment of the present invention. In the quantitative measurement method of the amount of preload of the cross roller bearing which concerns on one Embodiment of this invention, it is explanatory drawing which shows the state which inserted the cross roller bearing in the recess of the cylinder block in a casing, and bolted the outer ring | wheel holder | retainer. . It is a perspective view of a cross roller bearing used for a quantitative measurement method of the amount of preload of a cross roller bearing concerning one embodiment of the present invention. It is explanatory drawing which shows the structure of the cylinder block inside the casing used for the quantitative measurement method of the amount of preload of the cross roller bearing which concerns on one Embodiment of this invention. It is explanatory drawing which shows the state which inserted the cross roller bearing of FIG. 3 in the recess of the cylinder block of FIG. It is explanatory drawing which shows the state which mounted the outer ring | wheel presser on the cross roller bearing of FIG. It is explanatory drawing which shows the state which penetrated the volt | bolt to the outer ring | wheel holder of FIG. It is explanatory drawing which shows the state which bolting to the outer ring holder | retainer of FIG. 7 was completed. It is explanatory drawing which shows the state which installed the displacement meter in the predetermined position along one of the guide grooves of the outer ring | wheel holder of FIG. It is explanatory drawing which shows the state which loosened the bolt of the outer ring | wheel holder of FIG. It is explanatory drawing which showed notionally the preload state of the cross roller bearing of this invention. It is explanatory drawing which showed the specific bearing clearance amount measuring method with respect to the cross roller bearing which concerns on this invention. It is a figure explaining that outer ring variation | change_quantity (DELTA) s and radial clearance amount (DELTA) t are equal. It is the figure which showed the relationship between the amount of negative clearances and the preload which were obtained with the quantitative measurement method of the preload amount of the cross roller bearing of this invention. It is explanatory drawing which showed the type of cross-roller bearing which gives a preload to the outer ring made into object in this invention by flange-shaped outer ring holding | suppressing. It is the figure which showed the jig | tool in order to estimate the bolt tightening torque T and the axial load F. It is explanatory drawing which shows an example of the conventional cross roller bearing. It is explanatory drawing which shows another example of the conventional cross roller bearing.

[Embodiment 1]
In order to quantify the preload, it is necessary to clarify the axial load generated when the bolt is tightened. The relationship between the bolt tightening torque T and the axial load F is as follows: effective screw diameter d ₂ , screw pitch P, bearing surface equivalent friction diameter d _w , thread surface friction coefficient μ _s , seat surface friction coefficient μ _w , half angle of thread If α is expressed by the following equation.

From the above formula, the bearing surface friction coefficient and the thread friction coefficient of the bolt are determined. In the present embodiment, the friction coefficient is obtained by conducting an experiment using a jig (see FIG. 16 described later) made of the same material and the same processing method as the outer ring presser used in the subsequent friction torque measurement test. It was.

In the above equation, the following equation is obtained when the above equation is modified assuming that the bearing surface friction coefficient and the thread friction coefficient are equal μ.

From this equation, the axial load F can be estimated from the bolt tightening torque T, and this axial load F becomes a preload.

The target bearing in this embodiment is an outer ring matching type cross roller bearing as shown in FIGS.

Referring to FIG. 11, the outer ring matching type bearing has a structure in which the bearing clearance becomes negative and the preload acts when the outer ring is pressed by the outer ring presser.

When trying to quantify the pre-load of the cross roller bearing, it is very difficult to create a condition of zero bearing clearance. The reason for this is that the crossed roller bearing has a structure in which the rolling element comes into contact with the inner and outer rings and stabilizes only when the bearing clearance is negative, and the rolling element is not stable at the clearance near the bearing clearance 0. is there. The measurement of the bearing clearance is described in the JIS standard (JISB1515-2), but no clear measurement method for the cross roller bearing is described.

Therefore, as shown in FIG. 12, the initial state is defined as a state in which preload is applied to the outer ring, and when the preload is removed from the outer ring, the outer ring moves upward due to elastic recovery of the rolling elements. To do. The amount of change in the bearing clearance was confirmed by measuring the amount of displacement generated during this time, and the relationship between the axial load generated by the outer ring presser and the bearing negative clearance was determined.

As shown in FIG. 13, when the upper outer ring is moved downward with the lower outer ring fixed, the outer ring change amount Δs is equal to the radial clearance amount Δt. The radial clearance amount was estimated by measuring the outer ring change amount using the relationship in which the outer ring change amount Δs and the radial clearance amount Δt are equal.

Referring to FIGS. 1 to 16, the method for measuring the preload amount of the cross roller bearing (10) in which preload is applied to the outer ring by the flange-shaped outer ring retainer (4) according to the present embodiment includes the following steps.

Step (A): The coefficient of friction of the bolt (6) for tightening the outer ring retainer is measured in advance using a jig (see FIG. 16) made of the same material as the outer ring retainer (4).

Step (B): After the step (A), a preload is applied to the cross roller bearing (10) using the same type of bolt (6) as the bolt whose friction coefficient was measured in the step, and the outer ring (2) The pre-load is applied to the cylinder block (7a) in the bottomed casing (7) for measurement (see FIG. 4), and the cross roller bearing (10 The cross roller bearing (10) is inserted into a cylindrical recess (7b) (see FIG. 4) having a depth substantially equal to the thickness of ()) (see FIG. 5), and the outer ring of the cross roller bearing (10) ( 2) A process of placing the outer ring retainer (4) on top (see FIG. 6), and inserting the bolt (6) into the outer ring retainer (4) to determine the position of the outer ring retainer (4) (see FIG. 7). , Tighten the bolt (6) to the target torque, Screwed Linda block (7b), comprising the steps (see FIG. 8) which imparts a preload to the outer ring (2).

Step (C): The displacement meter (15) is installed at a predetermined position.

Step (D): The probe shaft (PR) of the displacement meter (15) is adjusted to be perpendicular to the cross roller bearing (10), the bolt (6) is loosened until it is separated from the seating surface, and the initial stage In order to guide the probe shaft (PR) having the contact of the displacement meter (15) at the tip thereof, the step of measuring the amount of displacement generated from the state to the end of the upward movement of the outer ring (2). The probe shaft (PR) is formed along three guide grooves (5) formed on the inner surface of the outer ring retainer along the axial direction of the cross roller bearing at positions spaced apart from each other by an equal angle (120 degrees). The amount of change in the bearing clearance is confirmed by bringing the contact of the displacement meter (15) into contact with the upper surface of the outer ring (2), and the axial load generated by the outer ring retainer (4) and the bearing are checked. Carry out the quantification of the relationship in Kemah. 2 and 6-10 show a state in which three or more guide grooves or holes are formed at positions separated from each other by the same angle (120 degrees), but in this embodiment, they are equal to each other. There is no need for an angle, and the number is not limited to three and may be two. In that case, a jig (plate) may be attached to the tip of the probe shaft (PR). FIG. 14 shows the relationship between the amount of negative clearance obtained by the present invention and the preload. In the present embodiment, it is possible to provide four or more guide grooves (5). Instead of the guide groove (5), a through hole (hereinafter simply referred to as “hole”) may be employed.

[Embodiment 2]
Referring to FIGS. 1 to 3, the cross roller bearing (10) according to this embodiment includes 90-degree V-grooves (1a) provided in the circumferential direction on the opposing surfaces of the inner ring (1) and the outer ring (2). Cylindrical rollers (3) rolling inside are provided.

In the cross roller bearing (10) according to the present embodiment, the outer ring (2) is fitted into the housing (7), and the outer ring (2) is fastened and fixed to the housing (7) via the bolt (6). A substantially annular outer ring presser (4) is provided for applying a preload by pressing the outer ring (2) in the axial direction.

,
The cross roller bearing (10) according to this embodiment has a guide groove (5) for guiding a probe shaft (PR) having a contact of a displacement meter (15) shown in FIGS. Three are formed on the inner surface of the presser (4) at positions spaced apart by an equal angle (120 degrees) along the axial direction of the cross roller bearing (10). According to FIGS. 1 and 2, three guide grooves (5) of the present embodiment are formed. However, in the present embodiment, the guide grooves (5) do not have to be at an equal angle to each other, and are not limited to three. There may be two. In that case, a jig (plate) may be attached to the tip of the probe shaft (PR). It is also possible to provide four or more guide grooves or holes (5). Instead of the guide groove (5), a through hole (hereinafter simply referred to as “hole”) may be employed.

The cross roller bearing (10) of the present embodiment shown in FIGS. 1 to 3 can also be applied to a structure as disclosed in Patent Document 2 described above. That is, in other words, the inner ring (1) is fitted to the rotating shaft of Patent Document 2 and fixed with the inner ring presser, and the outer ring (2) is fitted to the housing (2) of Patent Document 2 and fixed with the outer ring presser. Needless to say, you can.

According to a first aspect of the present invention, there is provided a method for measuring a preload amount of a cross roller bearing in which an outer ring is preloaded by a flange-shaped outer ring retainer, and is manufactured in advance using the same material as the outer ring retainer. The step of measuring the friction coefficient of the bolt that tightens the outer ring press using the jig, (B) After the step (A), using the same type of bolt as the bolt whose friction coefficient was measured in the step, A process of applying a preload to the cross roller bearing and initializing a state in which the preload is applied to the outer ring, which is formed in a cylinder block in a bottomed casing for measurement, and is approximately the thickness of the cross roller bearing. Inserting the cross roller bearing into a cylindrical recess of equal depth and placing an outer ring retainer on the outer ring of the cross roller bearing, and inserting the bolt into the outer ring retainer Determining the position of the outer ring presser, tightening the bolt to a target torque, screwing it on a cylinder block, and applying a preload to the outer ring; (C) installing a displacement meter at a predetermined position (D) Adjust so that it is perpendicular to the cross roller bearing, loosen the bolt until it leaves the seating surface, and measure the amount of displacement that occurs between the initial state and the end of the upward movement of the outer ring. In order to guide a probe shaft having a contact of the displacement meter at the tip thereof, three or more are formed on the inner surface of the outer ring retainer at mutually equal angular positions along the axial direction of the cross roller bearing. Check the amount of change in the bearing clearance by inserting the probe shaft along the guide groove or hole, and bringing the displacement meter contact into contact with the upper surface of the outer ring. Pre-load amount of the cross roller bearing, which has been difficult to perform quantitative measurement methods in the past, because it has a structure that includes a process for quantifying the relationship between the axial load generated by the outer ring presser and the bearing clearance. The measurement method can be quantified, and the excellent effect that the preload management of the cross roller bearing becomes easy can be achieved.

According to a second aspect of the present invention, there is provided a cross roller bearing comprising cylindrical rollers that roll in 90-degree V-grooves provided in the circumferential direction on opposing surfaces of an inner ring and an outer ring, respectively, A probe shaft having a substantially annular outer ring presser that is fitted with the outer ring and is fastened and fixed to the housing via a bolt and presses the outer ring in the axial direction to apply a preload, and has a displacement gauge contact at the tip. At least three guide grooves or holes are formed on the inner surface of the outer ring retainer along the axial direction of the cross roller bearing at equal angular positions. It is possible to provide a cross roller bearing in which the preload amount can be easily measured by the quantitative measurement method of the preload amount of the cross roller bearing according to the first aspect.

DESCRIPTION OF SYMBOLS 1 ... Inner ring 2 ... Outer ring 3 ... Cylindrical roller 4 ... Outer ring retainer 5 ... Guide groove 6 ... Bolt 7 ... · Casing 7a ··· Cylinder block 7b ··· Recess 10 · · · Cross roller bearing 15 · · · Displacement meter PR · · · Probe shaft

Claims (3)

A method for measuring a pre-roll amount of a cross roller bearing in which a pre-load is applied to the outer ring by pressing a flange-shaped outer ring,
(A) A step of measuring a friction coefficient of a bolt for tightening the outer ring retainer using a jig manufactured in advance with the same material as the outer ring retainer,
(B) After the step (A), using a bolt of the same type as the bolt whose friction coefficient was measured in the step, a preload is applied to the cross roller bearing and a preload is applied to the outer ring in an initial state. The cross roller bearing is inserted into a cylindrical recess having a depth substantially equal to the thickness of the cross roller bearing. A step of placing an outer ring retainer on the outer ring of the roller bearing, and inserting the bolt into the outer ring retainer to determine the position of the outer ring retainer, tightening the bolt to the target torque, screwing it to the cylinder block, A step including a step of applying a preload;
(C) installing the displacement meter at a predetermined position;
(D) Adjust so as to be perpendicular to the cross roller bearing, loosen the bolt until it leaves the seating surface, and measure the amount of displacement that occurs between the initial state and the end of the upward movement of the outer ring. Three or more guide grooves or holes on the inner surface of the outer ring retainer along the axial direction of the cross roller bearing in order to guide the probe shaft having the displacement gauge contact at the tip. The probe shaft is lowered along the guide groove or hole, and the displacement gauge contact amount is checked against the upper surface of the outer ring to check the amount of change in the bearing clearance. A method for measuring a preload amount of a cross roller bearing, comprising a step of quantifying a relationship between an axial load and a bearing clearance. A cross roller bearing comprising cylindrical rollers that roll in 90-degree V-grooves provided in the circumferential direction on opposite surfaces of the inner ring and the outer ring,
The outer ring is fitted into the housing;
A substantially annular outer ring presser that is fastened to the housing via a bolt and presses the outer ring in the axial direction to apply a preload;
At least three or more guide grooves or holes for guiding a probe shaft having a contact of a displacement meter at the tip are formed on the inner surface of the outer ring retainer along the axial direction of the cross roller bearing. Cross roller bearing. The cross roller bearing according to claim 2, wherein the inner ring is fitted to the rotation shaft, and the inner ring is fixed to the rotation shaft by an inner ring presser via a bolt.