JPH0942994A - Revolution bearing with revolution angle detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a high precision revolution angle. SOLUTION: In a revolution bearing, a scale 4 along a circumferential direction is provided on one bearing ring out of an inner ring 1 and an outer ring 2 which are rings of the bearing respectively. A detector 5 for revolution angle detection which is for reading the scale 4 is provided on the other bearing ring. It is desirable to form the scale 4 by alternately magnetizing a belt-like flexible synthetic resin-made magnet into S poles and N poles so as to make graduations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is equipped with a crane and other construction machines, transporters, industrial machines, etc., and has a turning angle detector with a turning angle detector for detecting a turning position and a stop position. Regarding bearings.

[0002]

2. Description of the Related Art In construction machines such as excavators and cranes,
For safe work, the rotation angle of the boom with respect to the vehicle body is displayed on the monitor in the driver's seat. They read the number of rotations of a turning motor with a sensor and convert it into a turning angle. In relation to industrial machinery, there is also an example in which the positioning of the turning portion is controlled by a target and a sensor that detects the target.

[0003]

In the case of converting the number of rotations of the turning motor into a turning angle, if the power transmission system is long, an error occurs due to the twist of the shaft or the like. In addition, the backlash of the gear shifts the response at the time of forward and reverse turning. In the case of the positioning sensor used in industrial machines, when changing the stop position, it is necessary to change the sensor or target position each time. Further, in order to stop in multiple stages, a plurality of sensors or targets are required, which complicates the structure and requires accuracy in the mounting position of each sensor or the like, which makes mounting work troublesome.

The present invention solves the above problems and provides a slewing bearing with a slewing angle detector, which can detect a slewing angle with high accuracy, and has a simple structure and mounting work of the angle detecting means. To aim. Another object of the present invention is to provide a slewing bearing with a slewing angle detector, in which a scale, which is a component thereof, can be commonly used for bearings having different diameters, and productivity can be improved and cost can be reduced. Still another object of the present invention is to provide stable angle detection performance for a long period of time without being affected by bending of a bearing or a frame due to a load.

[0005]

A slewing bearing with a slewing angle detector according to the present invention is a rolling bearing type slewing bearing, in which one of the inner ring and the outer ring, which is a ring, is circumferentially arranged. A scale is provided along the scale, and a detector for detecting a turning angle for reading the scale is provided on the other bearing ring directly or via another member. The scale is preferably a band-shaped flexible material provided with a scale for changing the signal of the detector. Further, the scale may be a magnetic scale, and the detector may perform magnetic detection. The scale may be graduated by a tooth row of a magnetic material, and the detector may read a change in magnetic field. The magnetic scale or tooth scale may be used, or a band-shaped flexible material may be used.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. This bearing is a single-row type slewing bearing in which rolling elements 3 made of steel balls or the like are interposed between an inner ring 1 and an outer ring 2 which are race rings. A scale 4 along the circumferential direction is provided on the upper end surface of the inner ring 1, and a detector 5 facing the scale 4 is installed above the inner diameter surface of the outer ring 2. The scale 4 and the detector 5 constitute a turning angle detector 6.

This bearing is used with the axial direction standing upright, and the outer ring 2 is displaced above the inner ring 1. The inner ring 1 is fixedly installed on the lower frame 10, and the outer ring 2
An upper frame 11 such as a turntable is attached to the upper surface of the. A fixed gear 12 having internal teeth is provided on the inner diameter surface of the inner ring 1. A drive gear (not shown) meshing with the fixed gear 12 is passed through a speed reducer by a drive device such as a motor installed in the upper frame 11. The rotation of the drive gear revolves along the fixed gear 12 so that the outer ring 2 is rotated together with the upper frame 11. Upper frame 11
When this bearing is applied to a swivel seat of a construction machine, for example, it becomes a swivel base equipped with a boom or a shovel. The raceway grooves 7, 8 of the rolling elements 3 provided on the inner ring 1 and the outer ring 2 are
Its cross-sectional shape is, for example, a shape in which a pair of arch surfaces is provided in a V shape, and it is possible to load both axial and radial loads by contacting the rolling elements 3 at four points as in the case of a four-point contact ball bearing. . A predetermined number of rolling elements 3 are inserted between the raceway grooves 7 and 8 formed of circumferential grooves, and a separator (not shown) made of resin or the like having a good sliding property is interposed between the adjacent rolling elements 3. The upper and lower ends of the bearing gap between the inner ring 1 and the outer ring 2 are closed by ring-shaped seals 13 and 14, respectively. These seals 1
Reference numerals 3 and 14 are made of rubber or a synthetic resin elastic body, and are mounted in the seal mounting grooves of the outer ring 2 and the inner ring 1, respectively, and the lips contact the upper end surface of the inner ring 1 and the lower end surface of the outer ring 2, respectively.

As shown in FIG. 1B, the scale 4 is a scale in which a strip-shaped flexible magnet made of synthetic resin is magnetized with S poles and N poles alternately. The scale 4 is linear in a natural state, but since the bearing diameter is large, it is bent in an arc shape and attached to the entire circumference of the inner ring 1. The detector 5 is composed of a magnetic sensor and is attached to the inner surface of the outer ring 2 at one or a plurality of positions so as to face the scale 4.

According to this construction, the outer ring 2 turns together with the upper frame 11 by driving the drive gear that meshes with the fixed gear 12 of the inner ring 1 by the motor installed in the upper frame 11 as described above. At this time, the detector 5 generates a pulse signal by the scale 4 of the inner ring 2. By counting this pulse signal, it is converted into angle data by the signal conversion means (not shown) and displayed. In this case, since the slewing bearing has a large diameter and the scale interval magnetized on the scale 4 can be reduced in proportion to the angle, the slewing angle can be detected with high accuracy. Further, since the scale 4 and the detector 5 directly measure the positional relationship between the actually swiveling portion and the fixed portion, there is no error such as a shift in response, which also enables highly accurate positioning. Further, since the band-shaped flexible scale 4 is used, it is possible to cope with bearings having different bearing diameters, common parts can be achieved, productivity is improved, and cost is reduced. Moreover, since the turning angle detector 6 including the scale 4 and the detector 5 can be measured in a non-contact manner, it is not affected by the bending of the bearing or the frame 11 due to the load, and stable measurement performance can be obtained for a long time.

In the above example, a flat strip-shaped scale 4 was used, but as shown in FIG.
A band-shaped material with a corrugated cross section along the longitudinal direction, and S at each wave crest
You may use the scale 4 which magnetized the pole and the N pole by turns. Further, as shown in FIG. 2B, the nonmagnetic base 4a
In addition, the slits 4c at regular intervals make the teeth 4 as a scale.
The scale 4 may be formed by stacking the strip-shaped members 4b such as magnetic metal plates in which rows d are formed. In this case, the detector 5
For example, a device having a built-in permanent magnet and a coil for reading a change in magnetic field is used. When the detector 5 with a built-in magnet is used, the scale 4 is simply a magnetic body.
The corrugated cross section as shown in FIG. In this case, if the shape of the wave crest is made to have concavo-convex shapes such as gear teeth, the detection of the pulse becomes reliable. Although the scale 4 is attached to the inner ring 1 in the above example, the scale 4 and the detector 5 may be attached to either side of the inner and outer rings. In this case, it is advantageous for processing the signal cable that the angle display side is the detection side.

3 to 5 each show another embodiment of the present invention. In these examples, as the scale 4 and the detector 5, those described in the example of FIG. 1 are used. In the example of FIG. 3, a scale 4 is provided on the inner diameter surface of the outer ring 2, and a detector 5 for reading the scale 4 is provided on the inner ring 1. In this example, as in the example of FIG. 1, the inner ring 1 is a fixed wheel and the outer ring 2 is a slewing wheel, but a gear 12A is provided on the outer ring 2 to provide a drive gear (not shown) of a drive device on the fixed frame 10. It is supposed to mesh with.

In the example of FIG. 4, the scale 4 and the detector 5 are placed inside the bearing, that is, the upper and lower seals 1 in the bearing gap.
It is provided between 3 and 14. The scale 4 is provided on the outer diameter surface of the inner ring 1, and the detector 5 is a hole 1 penetrating the outer ring 2 in the radial direction.
It is provided within 5. The upper seal 13 is fitted and attached to a groove provided in the outer peripheral portion of the upper end surface of the inner ring 1. Other configurations are the same as those in the example of FIG. In the example of FIG. 5, instead of directly providing the detector 5 on the outer ring 1 in the example of FIG. 1, the detector 5 is installed on the upper frame 11 which is a separate member. If the positional relationship such as the gap amount between the detector 5 and the scale 4 can be secured with high accuracy, the detector 5
May be attached to the upper frame 11. The turning angle detector 6 may be attached to the lower part of the bearing.

Although each of the above-described embodiments has been described as applied to a single-row ball bearing type slewing bearing, the present invention is applicable to a double-row ball bearing type, a cross roller type, and a three-row cylinder. Any rolling bearing such as a roller bearing type can be applied without particular limitation.

[0014]

According to the slewing bearing with a slewing angle detector of the present invention, a scale along the circumferential direction is provided on one of the inner ring and the outer ring, and a detector for detecting a slewing angle for reading the scale is provided. Since it is provided on the other bearing ring, the positional relationship between the part that actually turns and the fixed part is measured, so that there is no error such as a response deviation and highly accurate angle detection can be performed. In particular, the slewing bearing has a large diameter, and the scale is provided on the bearing ring along the circumferential direction, and since the scale interval can be made small in terms of angle ratio, highly accurate angle detection can be performed. Also, even when stopping in multiple stages, the scale and detector are each set to 1
Only one is required, and the structure and installation are easy. When the scale is made into a band-shaped flexible one, the scale can be commonly used for bearings having different diameters, and productivity can be improved and cost can be reduced. Where the scale is a magnetic scale and the detector is for magnetic detection, or the scale is graduated with a tooth row of a magnetic material, and the detector reads changes in the magnetic field. In some cases, since the measurement can be performed without contact, stable performance can be obtained for a long period of time without being affected by the bending of the bearing or the frame due to the load.

[Brief description of drawings]

FIG. 1A is a partial sectional view of a slewing bearing according to a first embodiment of the present invention, and FIG. 1B is an explanatory view of its scale.

2A and 2B are partial perspective views showing respective modified examples of the scale.

FIG. 3 is a partial sectional view of a slewing bearing according to another embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a slewing bearing according to still another embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a slewing bearing according to still another embodiment of the present invention.

[Explanation of symbols]

1 ... Inner ring, 2 ... Outer ring, 3 ... Rolling element, 4 ... Scale, 5 ...
Detector, 6 ... Rotation angle detector, 10 ... Lower frame, 1
1 ... Upper frame

Claims (4)

[Claims] 1. A rolling bearing type slewing bearing, in which one of the inner ring and the outer ring, which is a raceway ring, is provided with a scale along the circumferential direction, and a detector for detecting a rotation angle for reading the scale. A swivel bearing with a swivel angle detector, which is provided on the other race directly or through another member. 2. The slewing bearing with a slewing angle detector according to claim 1, wherein the scale is a strip-shaped flexible material provided with a scale for changing a signal of the detector. 3. The swivel bearing with a swivel angle detector according to claim 1, wherein the scale is a magnetic scale, and the detector performs magnetic detection. 4. The swivel with a swivel angle detector according to claim 1 or 2, wherein the scale is graduated with a tooth row of a magnetic material, and the detector reads a change in a magnetic field. bearing.