JP2006112595A - Rolling bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a whirling motion of a cage 9d and prevent generation of noise and vibration accompanying the whirling motion. In addition, the rotational speed of the cage 9d can be accurately measured.
SOLUTION: The distal end portions of rolling members 21 and 21 held in holding recesses 20 and 20 formed on the inner peripheral surface of a rim portion 16b of the retainer 9d are brought into contact with the outer peripheral surface of an inner ring equivalent member such as a hub. Or it makes rolling contact. With this configuration, a clearance between the inner surfaces of the pockets 18 and 18 and the rolling surface of the rolling element is ensured to ensure lubrication performance and prevent excessive force from being applied to each part of the cage 9d. The above-mentioned problem is solved by preventing the whirling motion.
[Selection] Figure 2

Description

  The rolling bearing unit according to the present invention is used for, for example, rotatably supporting a wheel with respect to a suspension device of an automobile and measuring a load applied to the wheel.

  For example, a rolling bearing unit is used to rotatably support a vehicle wheel with respect to a suspension device. In order to ensure the running stability of the vehicle, a running state stabilizing device for the vehicle such as an antilock brake system (ABS) or a traction control system (TCS) is widely used. According to these running state stabilizing devices such as ABS and TCS, the running state of the vehicle at the time of braking or acceleration can be stabilized, but in order to ensure this stability even under more severe conditions, the vehicle It is necessary to control the brakes and the engine by incorporating more information that affects the running stability of the vehicle.

  That is, in the case of the conventional running state stabilizing device such as ABS or TCS, since so-called feedback control is performed to detect the slip between the tire and the road surface and control the brake and the engine, the brake and engine Control is delayed for a moment. In other words, in order to improve performance under severe conditions, the so-called feed-forward control prevents slippage between the tire and the road surface, or the so-called brake one-side effect where the braking forces of the left and right wheels are extremely different. Cannot be prevented. Furthermore, it is impossible to prevent the running stability of a truck or the like from being deteriorated based on the poor loading state.

  In order to cope with such a problem, in order to perform the feedforward control or the like, one of a radial load and an axial load applied to the wheel is applied to the rolling bearing unit for supporting the wheel with respect to the suspension device. Or it is possible to incorporate a load measuring device for measuring both. Conventionally, what was described in patent documents 1-4 is known as a rolling bearing unit for wheel support with a load measuring device which can be used in such a case.

  Of these, Patent Document 1 describes a rolling bearing unit with a load measuring device capable of measuring a radial load. In the case of the first example of this conventional structure, by measuring the displacement in the radial direction between the outer ring that does not rotate and the hub that rotates on the inner diameter side of the outer ring by a non-contact type displacement sensor, The radial load applied to the hub is calculated. The obtained radial load is used not only to properly control the ABS but also to inform the driver of a bad loading condition.

  Patent document 2 describes a structure for measuring an axial load applied to a rolling bearing unit. In the case of the second example of the conventional structure described in Patent Document 2, bolts for connecting the fixed side flange to the knuckle are screwed at a plurality of positions on the inner side surface of the fixed side flange provided on the outer peripheral surface of the outer ring. Each load sensor is attached to a portion surrounding the screw hole. Each load sensor is clamped between the outer surface of the knuckle and the inner surface of the fixed flange in a state where the outer ring is supported and fixed to the knuckle. In the case of the load measuring device for the rolling bearing unit of the second example having such a conventional structure, the axial load applied between the wheel and the knuckle is measured by the load sensors.

  Further, in Patent Document 3, the displacement sensor unit supported at four positions in the circumferential direction of the outer ring and the L-shaped detection ring that is externally fitted and fixed to the hub are used to detect the above-described outer ring at the four positions. A structure is described in which the displacement of the hub in the radial direction and the thrust direction is detected, and the direction and magnitude of the load applied to the hub are determined based on the detected values of the respective parts.

  Furthermore, in Patent Document 4, a strain gauge for detecting dynamic strain is provided in a member corresponding to an outer ring whose rigidity is partially reduced, and the revolution speed of the rolling element is determined from the passing frequency of the rolling element detected by the strain gauge. A method for determining the axial load applied to the rolling bearing from the revolution speed is described.

  In the case of the first example of the conventional structure described in Patent Document 1, the load applied to the rolling bearing unit is measured by measuring the displacement in the radial direction between the outer ring and the hub using a displacement sensor. However, since the displacement amount in the radial direction is small, it is necessary to use a highly accurate displacement sensor in order to obtain this load with high accuracy. Since high-precision non-contact sensors are expensive, it is inevitable that the cost of the entire rolling bearing unit with a load measuring device increases.

  In the second example of the conventional structure described in Patent Document 2, it is necessary to provide as many load sensors as the bolts for supporting and fixing the outer ring to the knuckle. For this reason, coupled with the fact that the load sensor itself is expensive, it is inevitable that the cost of the entire load measuring device of the rolling bearing unit is considerably increased. In addition, the structure described in Patent Document 3 is more expensive than the structure described in Patent Document 1 because sensors are installed at four positions in the circumferential direction of the outer ring. Furthermore, the method described in Patent Document 4 needs to reduce the rigidity of a part of the outer ring equivalent member, and it may be difficult to ensure the durability of the outer ring equivalent member.

  Furthermore, as an invention for realizing a structure for accurately measuring a load applied to a rolling bearing unit at a low cost, there is an invention disclosed in Japanese Patent Application No. 2004-7655. The structure of this prior invention is a vertical load (radial load) applied to the rolling bearing unit based on the revolution speed of a pair of rolling elements (balls) constituting a rolling bearing unit which is a double row angular ball bearing. Or measure the lateral load (axial load). FIG. 4 shows a load measuring device for a rolling bearing unit according to the present invention. Since the structure of the rolling bearing unit itself is the same as that of a conventionally known wheel supporting rolling bearing unit, a detailed description thereof will be omitted, and the structure and operation of the load measuring device will be described below.

  In the case of the structure according to the previous invention, the sensor unit 4 is inserted through the mounting hole 3 formed in the portion between the double row outer ring raceways 2 and 2 at the intermediate portion in the axial direction of the outer ring 1 which is an outer ring equivalent member. 4 is protruded from the inner peripheral surface of the outer ring 1. The tip portion 5 is provided with a pair of revolution speed detection sensors 6 a and 6 b and a single rotation speed detection sensor 7. And the detection part of each revolution speed detection sensor 6a, 6b of these is provided in each holder 9a, 9b holding each rolling element 8a, 8b arranged in a double row freely, and detecting revolution speed The revolving speeds of the rolling elements 8a and 8b can be detected by being close to and facing the encoders 10a and 10b. Further, the rotational speed of the hub 12 can be detected by making the detection part of the rotational speed detection sensor 7 close to and opposed to the rotational speed detection encoder 11 fitted and fixed to the intermediate part of the hub 12 which is an inner ring equivalent member. It is said. According to the load measuring device for a rolling bearing unit according to the prior invention having such a configuration, a load (vertical load) applied between the outer ring 1 and the hub 12 regardless of fluctuations in the rotational speed of the hub 12. And lateral load).

That is, in the case of the load measuring device for a rolling bearing unit according to the above-described invention, an arithmetic unit (not shown) is configured to output the outer ring 1 and the hub 12 on the basis of detection signals sent from the sensors 6a, 6b, and 7. One or both of the vertical load and the horizontal load applied between the two are calculated. For example, when calculating the vertical load, the computing unit calculates the sum of the revolution speeds of the rolling elements 8a and 8b in each row detected by the revolution speed detection sensors 6a and 6b. The vertical load is calculated based on the ratio with the rotational speed of the hub 12 detected by the speed detection sensor 7. The lateral load is obtained by calculating the difference between the revolution speeds of the rolling elements 8a and 8b in each row detected by the revolution speed detection sensors 6a and 6b, and the difference between the difference and the rotation speed detection sensor 7 is detected. It calculates based on ratio with the rotational speed of the said hub 12 to do. This point will be described with reference to FIGS. In the following description, it is assumed that the contact angles α _a and α _b of the rolling elements 8a and 8b in each row are the same in a state where the lateral load Fy is not applied.

FIG. 5 schematically shows the rolling bearing unit for supporting the wheel shown in FIG. 4 and shows the action state of the load. A double row outer ring raceway 2 and 2 formed on the inner peripheral surface of the outer ring 1 that does not rotate while being supported by a suspension device, and a double column formed on the outer peripheral surface of the hub 12 that rotates together with the wheel while supporting and fixing the wheel. Preloads F ₀ and F ₀ are applied to the rolling elements 8 a and 8 b arranged in a double row between the inner ring raceways 13 and 13 in the row. In use, the rolling bearing unit receives a vertical load Fz from the road surface as a reaction to the weight of the vehicle body. Further, a lateral load Fy is applied due to centrifugal force applied during turning. These preloads F ₀ , F ₀ , vertical load Fz, and lateral load Fy all affect the contact angles α (α _a , α _b ) of the rolling elements 8a, 8b. Then, the contact angle alpha _a, the alpha _b is changed, respective rolling elements 8a, the revolution speed n _c and 8b changes. The pitch circle diameter of each of the rolling elements 8a, 8b is D, the diameter of each of the rolling elements 8a, 8b is d, the rotational speed of the hub 12 provided with the inner ring raceways 13, 13 is n _i , When the rotational speed of the outer race 1 provided with the outer ring raceway 2,2 to n _o, the revolution speed n _c is expressed by the following equation (1).
n _c = {1− (d · cos α / D) · (n _i / 2)} + {1+ (d · cos α / D) · (n _o / 2)} (1)

As is clear from this equation (1), the rolling elements 8a, the revolution speed n _c and 8b, these rolling elements 8a, the contact angle α (α _a, α _b) of 8b varies in response to changes in As described above, the contact angles α _a and α _b change according to the vertical load Fz and the lateral load Fy. Thus the revolution speed n _c is changed according to these vertical load Fz and the lateral loads Fy. In this example, the hub 12 is rotated, since the outer ring 1 is not rotated, specifically, with respect to the vertical direction load Fz, the revolution speed n _c is slow enough to increase. As for the lateral load Fy, as shown in FIG. 6, the revolution speed of the rolling elements 8a and 8a in the row supporting the lateral load Fy is increased (see the broken line a in FIG. 6). The revolution speed of the rolling elements 8b, 8b in the row not supporting Fy is slow (see the solid line B in FIG. 6). Accordingly, the rolling elements 8a of each row, based on the revolution speed n _c of 8b, will be determined the vertical load Fz and the lateral loads Fy.

However, the contact angle α which leads to a change in the revolution speed n _c, well above the vertical load Fz and the lateral load Fy changes while associated with each other, also varies the preload F _0, F ₀ To do. Also, the revolution speed n _c is changed in proportion to the rotational speed n _i of the hub 12. Therefore, these vertical load Fz, lateral loads Fy, preload F _0, F _0, to be considered in conjunction all the rotational speed n _i of the hub 12, it is impossible to correctly determine the revolution speed n _c . Of these, the preloads F ₀ and F ₀ do not change according to the operating state, so it is easy to eliminate the influence by initial setting or the like. The vertical load Fz contrast, lateral loads Fy, the rotational speed n _i of the hub 12, so constantly changing in accordance with the operating state, it is impossible to eliminate the influence by the initial setting or the like.

In view of such circumstances, in the prior invention, as described above, when the vertical load Fz is obtained, the revolution speeds of the rolling elements 8a and 8b in the respective rows detected by the respective revolution speed detection sensors 6a and 6b are detected. Is obtained, the influence of the lateral load Fy is reduced. Further, when obtaining the lateral load Fy, the influence of the vertical load Fz is reduced by obtaining the difference in revolution speed between the rolling elements 8a and 8b in each row. Further calculation, in any case, and the sum or difference, the vertical load Fz, or the lateral load Fy on the basis of the ratio between the rotational speed n _i of the hub 12 to the rotational speed detecting sensor 7 detects by and by eliminating the influence of the rotational speed n _i of the hub 12. However, the lateral load Fy, when calculating on the basis of the ratio of the revolution speed of the rolling elements 8a, 8b of each column, the rotational speed n _i of the hub 12 is not necessarily required.

There are various other methods for calculating one or both of the vertical load Fz and the lateral load Fy based on the signals of the revolution speed detection sensors 6a and 6b. Such a method is described in detail in the above-mentioned Japanese Patent Application No. 2004-7655, and is not related to the gist of the present invention, so detailed description thereof is omitted. Further, as shown in FIG. 7, fitted to fix the rotational speed detecting encoder 11a for obtaining the rotational speed n _i of the hub 12 to the inner end of the hub 12, the rotational speed detecting sensor 7a of the outer ring 1 It can also be supported by a cover 14 that closes the inner end opening.

  The above-described load measuring device for a rolling bearing unit according to the present invention can be manufactured at a relatively low cost as compared with the structures described in Patent Documents 1 to 4 described above, and the vertical direction applied to the rolling bearing unit. The load Fz or the lateral load Fy can be accurately obtained. However, in order to obtain these loads Fz and Fy accurately and with high accuracy (with high resolution), the revolution speeds of the rolling elements 8a and 8b in the respective rows detected by the respective revolution speed detection sensors 6a and 6b are determined. It needs to be accurate and highly accurate. In order to obtain the revolution speed with high accuracy, the revolution speed detecting encoders 10a and 10b are provided concentrically with the cages 9a and 9b in order to obtain the revolution speed as the rotation speed of the cages 9a and 9b. It is effective to increase the number of characteristic changes of the revolution speed detecting encoders 10a and 10b (to shorten the characteristic change pitch).

  Further, in order to accurately obtain the revolution speed, it is important to match the geometric center of each of the cages 9a and 9b with the rotation center (the revolution center of the rolling elements 8a and 8b in each row). On the other hand, in the detection signals of the respective revolution speed detection sensors 6a and 6b, there is an error in the magnetization pitch of the surface to be detected (pitch between the S pole and the N pole adjacent in the circumferential direction). The comparatively high frequency fluctuation | variation based and the comparatively low frequency fluctuation | variation accompanying the whirling motion of the holder | retainers 9a and 9b have entered. If such fluctuations are not processed (reduced), the revolution speeds of the rolling elements 8a and 8b in each row cannot be accurately obtained, and therefore the measurement accuracy of the vertical load and the horizontal load is deteriorated.

The reason why the above two types of fluctuations that lead to deterioration of the measurement accuracy of each load will be described with reference to FIGS. The inner surface of the pocket of the cage 9a (9b) holding the revolution speed detection encoder 10a (10b) (or having the function as the revolution speed detection encoder) and the surface of each rolling element 8a (8b) There is a gap between the (rolling surface) and the rolling elements 8a (8b) so as to be able to roll freely. Therefore, even if increasing much the assembling accuracy of the components, during operation of the rolling bearing unit, the center (rotational center of the hub 12) of the pitch circle of the rolling elements 8a (8b) O ₁₂ and the retainer 9a ( There is a possibility that the rotation center O _{9 of} 9b) is shifted by δ as shown in an exaggerated manner in FIG. Then, the revolution speed detecting encoder 10a on the basis of the deviation (10b) performs a rotation motion blur around the center O ₁₂ of the pitch circle.

  As a result of the whirling motion generated in this way, the detected surface of the revolution speed detecting encoder 10a (10b) has a moving speed in addition to the rotating direction. Then, a moving speed other than the rotational direction, for example, a horizontal moving speed in FIG. 8 is added to or subtracted from the moving speed in the rotational direction. On the other hand, the revolution speed detection sensor 6a (6b) detects the revolution speed of each rolling element 8a (8b) based on the moving speed of the detected surface of the revolution speed detection encoder 10a (10b). The eccentricity of δ affects the detection signal of the revolution speed detection sensor 6a (6b) in which the detection surface faces the side surface of the revolution speed detection encoder 10a (10b).

  When the detection surface of the revolution speed detection sensor 6a (6b) is opposed to the side surface of the revolution speed detection encoder 10a (10b), the detection signal of the revolution speed detection sensor 6a (6b) is as shown in FIG. As shown by the chain line α in FIG. That is, even when the revolution speed of each rolling element 8a (8b) is constant, the revolution speed represented by the output signal of the revolution speed detection sensor 6a (6b) is sinusoidally as shown by the chain line α. Change. Specifically, when the moving speed in the left-right direction in FIG. 8 is added to the moving speed in the rotational direction, the output signal is a signal corresponding to a speed faster than the actual revolution speed. Conversely, when the moving speed in the left-right direction in FIG. 8 is subtracted from the moving speed in the rotational direction, the output signal is a signal corresponding to a speed slower than the actual revolution speed. FIG. 8 shows the eccentricity δ exaggerated as compared with the actual case. For example, the vertical load Fz and the lateral load Fy applied to the rolling bearing unit are further increased in order to more strictly control for vehicle stability. In the case of obtaining accurately, it is necessary to eliminate the error due to the eccentricity.

  The pitch of the characteristic change on the side surface of the revolution speed detecting encoder 10a (10b) (for example, the pitch between the S pole and the N pole arranged on the side surface) should be essentially the same, but a manufacturing error (for example, Due to magnetization errors, etc., they may be slightly different from each other. Even based on this error, the detection signal of the revolution speed detection sensor 6a (6b) varies. The period of variation based on such an error in the magnetized pitch is much shorter (higher frequency) than the period of variation based on the above-mentioned whirling motion. For example, when the characteristic (repetition of S pole and N pole) of the side surface (detected surface) of the revolution speed detecting encoder 10a (10b) changes 60 times on the entire circumference of the detected surface, the magnetization is performed. The fluctuation period based on the pitch error is about 1/60 of the fluctuation period based on the swing motion.

  The detection signal output from the revolution speed detection encoder 10a (10b) is as shown by a solid line β in FIG. 9 in which the above two types of fluctuations are added (superimposed). In order to accurately obtain the vertical load Fz and the lateral load Fy, it is necessary to reduce the two types of fluctuations. Among such variations, the relatively high frequency variation based on the manufacturing error such as the magnetization pitch is an electrical signal using an averaging filter, which has been widely known as a signal processing method. It can be easily reduced by processing.

  On the other hand, in order to prevent the deterioration of the accuracy of the revolution speed detection based on the relatively low frequency fluctuation accompanying the swinging motion, the revolution speed detection encoder is arranged at two positions on the opposite side in the radial direction. By adding the detection signals of the pair of revolution speed detection sensors, it is possible to eliminate the influence of the deviation between the two centers. However, in this case, two revolution speed detection sensors are required, which may increase the cost and installation space, and may be difficult to adopt.

  On the other hand, in the case of a general rolling bearing unit for a passenger car, each of the above-mentioned holdings can be achieved if a gap in the radial direction of the cage (pocket gap) between the rolling surface and the inner surface of the pocket is kept small. Even in a so-called rolling element guide structure in which positioning in the radial direction of the vessel is achieved by a rolling element, it is considered that the accuracy of the revolution speed can be suppressed to a practically satisfactory level. However, when the rolling bearing unit is used under the condition of supporting a large moment (torsional moment) in a direction in which the central axis of the outer ring 1 and the central axis of the hub 12 are displaced, if the clearance with respect to the pocket is simply reduced, The following problems arise. That is, when a moment as described above is applied, the contact angle between each rolling element and the outer ring raceway and the inner ring raceway is different for each rolling element (becomes non-uniform). It will be in a state where it does not line up. In such a state, if the clearance regarding the pocket is set small, the contact load between the inner surface of any pocket and the rolling surface of the rolling element increases. And a frictional force becomes large in the said contact part, and causes the rotation speed of the said rolling element and by extension, the revolution speed of all the rolling elements to become smaller than the value corresponding to a contact angle. If an error occurs in the revolution speed of the rolling element due to such a cause, it becomes impossible to accurately measure the load acting between the outer ring 1 and the hub 12 based on the revolution speed. Further, if the gap relating to the pocket is made too small, the lubricant may be prevented from flowing into the gap, the lubrication state may be hindered, and abnormal vibration may be caused. When these things are taken into consideration, it is desirable that the gaps related to the pockets be made larger than a certain extent for all pockets.

  In view of such circumstances, Japanese Patent Application No. 2003-32148 discloses an invention that suppresses the whirling motion of the revolution speed detecting encoder with a structure as shown in FIGS. Of these, in the case of the structure shown in FIG. 10, the weight 15 is made heavier than the other parts by fixing the weight 15 to a part in the circumferential direction of the retainer 9a (9b). When the cage 9a (9b) rotates in accordance with the revolving motion of the rolling elements 8a, 8a (8b, 8b), the cage 9a (9b) has a portion provided with the weight 15 at the outermost radial direction. Sway around in a displaced state. Further, the assembly position of the revolution speed detecting encoder 10a (10b) with respect to the side surface of the rim portion 16 of the cage 9a (9b) is shifted by δ from the mounting position of the weight 15 to the opposite side by 180 degrees. . This δ is commensurate with the eccentricity δ shown in FIG. 8, and corresponds to the radial displacement of the cage 9a (9b) based on the gap between the inner surface of the pocket and the rolling surface. The size to be.

  In the case of the structure shown in FIG. 10, the swinging direction of the cage 9a (9b) is uniquely restricted and the revolution speed detecting encoder 10a (10b) for the cage 9a (9b) is controlled. The assembly position is shifted by the radial displacement of the cage 9a (9b) on the opposite side in the diametrical direction with respect to the swinging direction. Therefore, when the rolling elements 8a, 8a (8b, 8b) revolve, the rotation center and the geometric center of the revolution speed detecting encoder 10a (10b) regardless of the swinging motion of the cage 9a (9b). Match. For this reason, it is possible to prevent the low-frequency fluctuation as shown by the chain line α in FIG. 9 from entering the detection signal of the revolution speed detection sensor 6a (6b).

  In the case of the structure shown in FIG. 11, the revolution speed detecting encoder 10a (10b) is supported and fixed to the retainer 9a (9b) in a state where the geometric centers thereof are aligned with each other. Then, positioning of the cage 9a (9b) in the radial direction is performed by an inner ring guide in which a part of the inner circumferential surface of the cage 9a (9b) is made to face and face the outer circumferential surface of the hub 12. With this configuration, when the cage 9a (9b) rotates with the revolution motion of each rolling element 8a (8b), the cage 9a (9b) hardly swings and the revolution speed is reached. It is possible to prevent low-frequency fluctuations as shown by the chain line α in FIG. 9 from entering the detection signal of the detection sensor.

  However, in the case of the structure shown in FIG. 10, in order to uniquely regulate the swinging direction of the cage 9a (9b), the centrifugal force acting on the weight 15 is increased to some extent, The cage 9a (9b) needs to be surely displaced in the direction in which the weight 15 is installed. That is, since the centrifugal force is proportional to the square of the rotational speed {revolution speed of each rolling element 8a (8b)}, the above weight is used to regulate the swinging direction of the cage 9a (9b) from the low speed running. It is necessary to use the one having a heavy weight as 15. However, the heavy weight 15 is not preferable because it generates an excessive centrifugal force during high-speed traveling and may cause damage to the cage 9a (9b).

  In the case of the structure shown in FIG. 11, if the clearance between the inner peripheral surface of the cage 9a (9b) and the outer peripheral surface of the hub 12 is too small, thermal expansion (shrinkage) due to temperature change occurs. Furthermore, there is a possibility that these two peripheral surfaces come into contact with each other (the gap is lost) and cannot be rotated normally. In particular, when the cage 9a (9b) is made of a material other than steel, such as a synthetic resin such as a polyamide resin, the linear expansion coefficient is different from that of the hub 12 made of steel. Therefore, it is difficult to set the above gap small. In addition, in the case of a cage made of a synthetic resin, it is preferable compared to a cage made of metal such as steel or copper-based alloy because it is lightweight and can reduce sliding friction acting between the rolling elements. It is difficult to improve the size and shape accuracy of a cage having a shape. In addition, even after molding, there is a case where deformation (roundness deteriorates) due to temperature rise during use, so the peripheral surface of the cage and the counterpart peripheral surface are uniform over the entire circumference in the entire temperature range to be used. It is difficult to face each other through a small gap.

  In the above description, in order to accurately obtain the revolution speed of each rolling element, the necessity to suppress the swinging motion of the cage holding each rolling element has been described. However, it is necessary to suppress the swinging motion of the cage from other aspects than to accurately obtain the revolution speed of each rolling element. That is, even in the case of a general rolling bearing unit, the gap existing between the inner surface of each pocket provided in the cage and the rolling surface of each rolling element is too large, and this cage is centered on the swinging motion. When an unstable movement is performed, there is a problem that noise or vibration called so-called cage sound is generated. When such noise and vibration occur, the stress inside the cage increases, which not only leads to breakage of this cage, but also when the rolling bearing unit is incorporated in acoustic equipment, precision equipment, etc. Will degrade the performance of the device. Also from such a surface, it is necessary to suppress the whirling motion of the cage incorporated in the rolling bearing unit.

JP 2001-21577 A Japanese Patent Laid-Open No. 3-209016 Japanese Patent Laid-Open No. 2004-3918 Japanese Patent Publication No.62-3365

  In view of the circumstances as described above, the present invention can reliably suppress the whirling motion of the cage holding each rolling element from the time of low-speed rotation, and the rolling bearing unit can be connected to the central axis of the outer ring equivalent member. Structure that prevents excessive force from being applied to the cage and ensures lubricity even when used in situations where a large moment in the direction of shifting the center axis of the inner ring equivalent member is supported. Was invented to make it feasible.

  Each of the rolling bearing units of the present invention is similar to a conventionally known rolling bearing unit, an outer ring equivalent member having an outer ring raceway on an inner peripheral surface, an inner ring equivalent member having an inner ring raceway on an outer peripheral surface, and these outer rings. A synthetic resin cage having a plurality of rolling elements provided between the raceway and the inner ring raceway so as to be freely rotatable, and a plurality of pockets for holding each of the rolling elements inside each of the rolling elements, and the holding And a revolving speed detecting encoder provided concentrically with the cage.

  In particular, in the rolling bearing unit according to the first aspect, a metal-made annular reinforcing ring is supported and fixed to the rim portion of the cage (by bonding, press-fitting, insert molding or the like). At the same time, any one of the peripheral surfaces of the rim portion that supports and fixes the reinforcing ring is brought close to and opposed to any one of the inner peripheral surface of the outer ring equivalent member and the outer peripheral surface of the inner ring equivalent member. Thus, positioning in the radial direction of the cage is achieved.

  Further, in the rolling bearing unit according to claim 3, the roller bearing unit is held at three or more positions separated in the circumferential direction on any one of the inner and outer peripheral surfaces of the rim portion of the cage. A recess is provided. In addition, the installation positions of these holding recesses are not concentrated in the semicircular circumference of the rim portion. In other words, the at least one holding recess is present on a semicircular circumference opposite to the semicircular circumference where the remaining holding recesses are present. For this purpose, preferably, the three or more holding recesses are provided at equidistant positions in the circumferential direction. Then, a part of the rolling member that is rotatably held in each of the holding recesses is protruded in the radial direction from any one of the peripheral surfaces and the same dimension in the radial direction from the peripheral surface. At the same time, the tip of the part of each rolling member protruding from the peripheral surface is abutted against any one of the inner peripheral surface of the outer ring equivalent member and the outer peripheral surface of the inner ring equivalent member. Positioning in the radial direction of the cage is achieved by making contact or proximity.

  According to the rolling bearing unit of the present invention, the vibration in the radial direction of the cage can be suppressed to be small, and the revolution speed of each rolling element based on the revolution speed detection encoder installed in the cage, and hence the revolution speed. The load applied between the outer ring equivalent member and the inner ring equivalent member, which is calculated based on this, can be accurately obtained. Moreover, since the size of the gap existing between the inner surface of each pocket and the rolling surface of each rolling element can be secured, the large moment that each rolling element acts between the outer ring equivalent member and the inner ring equivalent member. Even when used under the condition of supporting the cage, it is possible to prevent excessive force from being applied to the cage and to ensure lubricity.

When the invention described in claim 1 is carried out, preferably, as described in claim 2, the reinforcing ring is made of magnetic metal, and an encoder made of a permanent magnet is attached to the reinforcing ring.
By adopting such a configuration, it is possible to improve the reliability of the rotational speed detection of the cage using this encoder by increasing the strength of the magnetic flux emitted from the detection surface of this encoder. Further, by increasing the distance between the detected surface of the encoder and the detecting portion of the sensor, it is possible to prevent the detected surface and the detecting portion from rubbing regardless of the displacement of each portion.

Further, when the invention described in claim 3 is carried out, preferably, as described in claim 4, the inner surface of each holding recess is a partially spherical concave surface and each rolling member is spherical.
If comprised in this way, each of these rolling members will roll smoothly based on the contact with the any one peripheral surface of the inner peripheral surface of an outer ring equivalent member, and the outer peripheral surface of an inner ring equivalent member, and a holder | carrier will rotate. The resistance to things can be kept small.

When the present invention is carried out, the rolling element may be a ball as described in claim 5 or a tapered roller as described in claim 6.
Further, the use is not particularly limited, but as described in claim 7, the use is provided between a suspension device of an automobile and a wheel and is used to rotatably support the wheel with respect to the suspension device. Considered most practical.
Further, as in the case of the above-described prior invention, as described in claim 8, in order to measure the rotational speed of the cage that matches the revolution speed of each rolling element, a characteristic is given to a part of the cage. It is conceivable that the encoders that are alternately and equally spaced in the circumferential direction are supported and fixed, and the detection unit of the revolution speed detection sensor is installed facing the detection surface of the encoder. Then, the detection signal of the revolution speed detection sensor is used to obtain a load applied between the outer ring equivalent member and the inner ring equivalent member.

  FIG. 1 shows a first embodiment of the present invention corresponding to claims 1 and 2. The feature of the present embodiment is that the rolling bearing unit is used in a situation where a large moment in a direction in which the central axis of the outer ring equivalent member and the central axis of the inner ring equivalent member are displaced is supported. With a structure in which the gap between the inner surface of the pocket and the rolling surface of the rolling element is increased to some extent in order to prevent excessive force from being applied to the cage made of synthetic resin and to ensure lubricity, It is in the point which implement | achieves the structure which can suppress reliably the whirling motion of a cage | basket from the time of low speed rotation. Since the structure of the rolling bearing unit and the structure of the part for obtaining the load applied to the rolling bearing unit based on the rotational speed of the cage are the same as those of the above-described prior invention, the illustration and explanation of the equivalent part are as follows. Omitted, and the characteristic part of the present embodiment will be described below.

In the case of this embodiment, an annular (annular) reinforcing ring 17 made of a magnetic metal such as low carbon steel is provided on a rim portion 16a of a crown-shaped cage 9c made of a synthetic resin such as polyamide resin or polyphenylene sulfide resin. Support embedding. At the same time, the inner diameter R ₁₆ of the rim portion 16a in which the reinforcing ring 17 is embedded is an intermediate portion in the axial direction of the hub 12 that is a member corresponding to an inner ring constituting the rolling bearing unit to which the cage 9c is to be assembled. portion of the outer diameter D ₁₂ of the inner peripheral surface of the rim portion 16a is opposed slightly (for example, about 0.04～0.2Mm) than (see FIG. 4) increases _{{R 16 ≒ D 12 + (} 0.04~0 .2 mm)}. Therefore, when the inner peripheral surface of the rim portion 16a and the outer peripheral surface of the intermediate portion of the hub 12 are arranged concentrically with each other, the thickness in the radial direction is between 0.02 and 0.02. A minute gap of about 0.1 mm exists over the entire circumference.

  According to the rolling bearing unit of this embodiment provided with the retainer 9c in which the reinforcing ring 17 as described above is embedded in the rim portion 16a, the radial deflection of the retainer 9c can be suppressed to be small. That is, the shape accuracy and dimensional accuracy of the reinforcing ring 17 can be sufficiently improved. Moreover, the dimension regarding the radial direction of the part which protrudes inward in a radial direction rather than the inner periphery of the said reinforcement ring 17 among the said rim | limb parts 16a is few. Therefore, even if there is a deformation associated with the injection molding of the synthetic resin, the deviation from the design value of the size and shape of the inner peripheral surface of the portion protruding inward in the radial direction can be suppressed to a minimum. For this reason, even if the inner peripheral surface of the synthetic resin portion in the rim portion 16a is close to and opposed to the outer peripheral surface of the intermediate portion of the hub 12, there is a minute gap as described above between the two peripheral surfaces. Can be made to exist all around. Then, the cage 9c can be prevented from swinging in the radial direction.

  In this way, in preventing the cage 9c from swinging, the inner surfaces of the pockets 18, 18 and the rolling elements 8a (8b, see FIGS. 4 and 7) held in the pockets 18, 18 are provided. The size of the gap existing between the two can be secured. Therefore, it is used in a situation where all the rolling elements do not exist on the same virtual plane as a result of supporting a large moment acting between the outer ring 1 and the hub 12 (see FIGS. 4 and 7). Even if it is a case, it can prevent that an excessive force is added to the said holder | retainer 9c. Further, the lubricating oil can be reliably fed into the gap between the inner surface of each of the pockets 18 and 18 and the rolling surface of each of the rolling elements 8a (8b), thereby ensuring lubricity.

  In the illustrated embodiment, a revolving speed detecting encoder 10 made of a permanent magnet is attached to the magnetic metal reinforcing ring 17. The revolution speed detecting encoder 10 is magnetized in the axial direction, and the magnetization direction is changed alternately and at equal intervals in the circumferential direction. If such a revolution speed detecting encoder 10 is attached to the reinforcing ring 17, the strength of the magnetic flux emitted from the detected surface (the right side surface in FIG. 1) of the revolution speed detecting encoder 10 can be increased. For example, the reach distance of the magnetic flux from the detected surface can be increased. As a result, it is possible to improve the reliability of the rotational speed detection of the cage 9c using the revolution speed detection encoder 10.

  2 and 3 show a second embodiment of the present invention corresponding to claims 3 and 4. In the case of the present embodiment, the holding recesses are respectively formed in the base portions of the column portions 19 and 19 existing between the pockets 18 and 18 adjacent in the circumferential direction on the inner peripheral surface of the rim portion 16b of the cage 9d. 20 and 20 are provided. Each of the holding recesses 20 and 20 has a partially spherical concave surface on the inner surface. The spherical rolling members 21 and 21 can be rolled into the respective holding recesses 20 and 20 in a state in which each part protrudes from the inner peripheral surface of the rim portion 16b by the same dimension inward in the radial direction. Hold on. At the same time, the tip of the portion of each of the rolling members 21 and 21 protruding from the inner peripheral surface of the rim portion 16b is brought into contact with the outer peripheral surface in the axial direction intermediate portion of the hub 12 (see FIGS. 4 and 7). Positioning in the radial direction of the retainer 9d is achieved by (rolling contact) or close proximity.

  Also in the case of the rolling bearing unit of the present embodiment incorporating the cage 9d configured as described above, the revolution speed detecting encoder installed in the cage 9d can be kept small in the radial deflection of the cage 9d. Therefore, the load applied between the outer ring equivalent member and the inner ring equivalent member, which is calculated based on the revolution speed of each rolling element based on the above, and thus based on this revolution speed, can be accurately obtained. In addition, since the size of the gap existing between the inner surface of each pocket 18 and 18 and the rolling surface of each rolling element can be secured, a large moment between the outer ring 1 and the hub 12 (see FIGS. 4 and 7). Even when it is used under the condition of supporting the above, it is possible to prevent excessive force from being applied to the retainer 9d and to ensure lubricity.

Sectional drawing of the holder | retainer integrated in Example 1 of this invention. The perspective view of the holder | retainer integrated in the Example 2. FIG. The A section enlarged view of FIG. Sectional drawing which shows the 1st example of the rolling bearing unit for wheel support with a load measuring device which concerns on a prior invention. The schematic diagram for demonstrating the reason which can measure a load with the structure which concerns on this prior invention. The diagram which shows the relationship between a horizontal direction load and the fluctuation | variation of the revolution speed of each row | line | column. Sectional drawing which shows the 2nd example of the rolling bearing unit for wheel support with a load measuring device which concerns on a prior invention. The schematic diagram for demonstrating the reason for the whirling motion of a cage | casing worsening the precision of revolution speed detection. The diagram showing the output signal of a revolution speed detection sensor similarly. The end view which shows an example of the structure considered previously in order to prevent the whirling of the encoder for revolution speed detection irrespective of the whirling motion of a holder | retainer. The fragmentary sectional view which shows one example of the structure considered previously in order to prevent the whirling motion of a holder | retainer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Outer ring raceway 3 Mounting hole 4 Sensor unit 5 Tip 6a, 6b Revolution speed detection sensor 7, 7a Rotational speed detection sensor 8a, 8b Rolling elements 9a, 9b, 9c, 9d Retainer 10, 10a, 10b Revolution Speed detection encoder 11, 11a Rotational speed detection encoder 12 Hub 13 Inner ring raceway 14 Cover 15 Weight 16, 16a, 16b Rim part 17 Reinforcement ring 18 Pocket 19 Column part 20 Holding recess 21 Rolling member

Claims (8)

  An outer ring equivalent member having an outer ring raceway on an inner peripheral surface, an inner ring equivalent member having an inner ring raceway on an outer peripheral surface, and a plurality of rolling elements provided in a freely rollable manner between the outer ring raceway and the inner ring raceway, A retainer made of synthetic resin having a plurality of pockets for holding each of these rolling elements inside, and a revolving speed detection encoder provided concentrically with the retainer at a part of the retainer. In the rolling bearing unit, a metal-made annular reinforcing ring is supported and fixed to the rim portion of the cage, and any peripheral surface of the rim portion supporting and fixing the reinforcing ring is attached to the outer ring equivalent member. A rolling bearing unit characterized in that positioning in the radial direction of the retainer is achieved by causing the inner peripheral surface and any one of the outer peripheral surfaces of the inner ring equivalent member to approach each other.   The rolling bearing unit according to claim 1, wherein the reinforcing ring is made of a magnetic metal, and an encoder made of a permanent magnet is attached to the reinforcing ring.   An outer ring equivalent member having an outer ring raceway on an inner peripheral surface, an inner ring equivalent member having an inner ring raceway on an outer peripheral surface, and a plurality of rolling elements provided in a freely rollable manner between the outer ring raceway and the inner ring raceway, A retainer made of synthetic resin having a plurality of pockets for holding each of these rolling elements inside, and a revolving speed detection encoder provided concentrically with the retainer at a part of the retainer. In the rolling bearing unit, holding recesses are provided at three or more positions separated in the circumferential direction on either of the inner and outer peripheral surfaces of the rim portion of the cage, and each of these holding recesses is provided. A part of the rolling member held so as to roll freely protrudes from one of the peripheral surfaces in the radial direction by the same dimension in the radial direction from the peripheral surface, and a part of each of the rolling members protrudes from the peripheral surface. The tip of the part that is By abut or closely opposed to any of the peripheral surface of the inner periphery and the outer periphery of the inner ring equivalent member, the rolling bearing unit, characterized in that tried to positioning in the radial direction of the cage.   The rolling bearing unit according to claim 3, wherein an inner surface of each holding recess is a partially spherical concave surface, and each rolling member is spherical.   The rolling bearing unit according to claim 1, wherein the rolling elements are balls.   The rolling bearing unit according to claim 1, wherein the rolling element is a tapered roller.   The rolling bearing unit according to any one of claims 1 to 6, wherein the rolling bearing unit is provided between a suspension device and a wheel of an automobile and is used to rotatably support the wheel with respect to the suspension device.   In order to measure the rotational speed of the cage that matches the revolution speed of each rolling element, an encoder whose characteristics are alternately and equally spaced in the circumferential direction is supported and fixed to a part of the cage, Install the revolution speed detection sensor facing the detection surface of the encoder, and obtain the load applied between the outer ring equivalent member and the inner ring equivalent member using the detection signal of the revolution speed detection sensor. The rolling bearing unit according to claim 1, which is used for the purpose.

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