JP4609609B2 - Bearing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bearing device including a ball bearing as a component, and more particularly to a bearing device suitable for a field where a large load capacity is required and downsizing is required.
[0002]
[Prior art]
For example, an anti-lock brake system (ABS) or a traction control system, which is one of the brake systems of an automobile, is equipped with a piston pump that pumps up brake fluid in a reservoir and sends it to a master cylinder. Conventionally, the driving of the pump is generally performed by converting the rotation of the electric motor by a cam and transmitting it to the piston, but recently, a bearing is used to obtain a more stable driving of the pump. A motion conversion mechanism has been adopted.
[0003]
FIG. 8 shows a conventional motion conversion mechanism using such a bearing. An eccentric shaft 2 is eccentrically connected to the output shaft 1 of the motor, and a general-purpose ball bearing 3 is connected to the eccentric shaft 2. And the outer ring 4 of the ball bearing 3 is abutted against the piston P of the pump. According to such a motion conversion mechanism, when the output shaft 1 rotates, the ball bearing 3 performs a circular motion around the axis of the output shaft 1 integrally with the eccentric shaft 2, and the piston P follows the A -Reciprocating movement as indicated by arrow A '.
[0004]
[Problems to be solved by the invention]
Recently, higher performance and higher functionality of the above-described ABS and the like have been promoted, and along with this, the load capacity required for the ball bearing 3 tends to increase more and more. However, in the case of using only one general-purpose single-row ball bearing 3 as in the conventional motion conversion mechanism described above, in order to increase the load capacity, the bearing must be changed to one having a large allowable load rating, that is, a large size. However, considering the current situation in which demands for miniaturization of automobile parts are becoming more and more severe, there is a limit to the size increase itself, and the development of a new bearing device has been desired.
[0005]
As a countermeasure for the above-described problem, for example, a needle roller bearing 6 using a needle roller 5 as a rolling element as shown in FIG. 9 is adopted instead of the ball bearing 3, and as shown in FIG. A double-row bearing 8 in which balls (balls) 7 as rolling elements are arranged in two rows, or a combination bearing 9 in which two small single-row ball bearings 9A and 9B are combined as shown in FIG. There is a way of thinking, such as adopting. However, when the needle roller bearing 6 is adopted, in addition to its high cost itself, the size of the double row bearing 8 cannot be reduced due to the restriction of the width dimension W (FIG. 9). In the case of adoption, since it is a dedicated design, a troublesome design change is required and the cost burden increases. Further, when the combination bearing 9 is adopted, the contact between each single-row ball bearing 9A, 9B and the piston P Therefore, the load is not evenly transmitted to the two single-row ball bearings 9A and 9B, and both of them have a problem.
[0006]
The present invention has been made in view of the above-described conventional technical background, and an object of the present invention is to achieve both an improvement in load capacity and a reduction in size without so much cost increase. It is to provide a bearing device.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a bearing device used in a motion conversion mechanism that converts rotation of the output shaft of a motor including an output shaft connected with an eccentric shaft into reciprocating motion of a piston, A plurality of single-row ball bearings are in close contact with each other and flanged with single-row ball bearings positioned at both ends in the sleeve, and are fitted onto the eccentric shaft, and the sleeve is in contact with the piston. It is characterized by combining.
By constituting in this way, when reciprocating motion is caused in the piston that collides with the sleeve following the circular motion around the axis of the output shaft of the sleeve and the ball bearing accompanying the rotation of the output shaft, Since the load is evenly transmitted to the plurality of single-row ball bearings via the sleeve, a sufficient load capacity is exhibited even when a small single-row ball bearing is combined.
[0008]
In the present invention, it is desirable that the flange of the single row ball bearing is disposed in contact with the end face of the sleeve or at a slight distance.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a bearing device as one embodiment of the present invention. The bearing device 10 is used in place of the ball bearing 3 (FIG. 8) in a motion conversion mechanism that drives a piston-type pump in the antilock brake system or the traction control system. The same parts as those shown in FIG.
[0010]
The bearing device 10 is schematically configured from one sleeve 11 and two single row ball bearings 12A and 12B assembled to the sleeve 11. Each single row ball bearing 12A, 12B is composed of a bearing portion 13A, 13B and a flange portion 14A, 14B provided at one end of each bearing portion 13A, 13B. The respective bearing portions 13A, 13B are mutually connected. In this state, the flange portions 14A and 14B are disposed in contact with the end surface of the sleeve 11 or slightly apart from each other. The single-row ball bearings 12A and 12B are structurally the same as conventional general-purpose flange bearings, and a plurality of balls (balls) are provided by using a cage (not shown) between the inner ring 15 and the outer ring 16. 17 has an equal arrangement in the circumferential direction, and the flange portions 14A and 14B are integrally provided on the outer ring 16 thereof.
[0011]
The two single row ball bearings 12A and 12B are closely fitted to the sleeve 11 by press-fitting the bearing portions 13A and 13B into the sleeve 11 from both ends as shown in FIG. It is integrated. Therefore, the length L _S of the sleeve 11 is the sum of the lengths L _A and L _B of the bearing portions 13A and 13B of the single-row ball bearings 12A and 12B (L _A + L _B , where L _A = L _B ). It is set to be equivalent or slightly shorter (L _S ≦ L _A + L _B ), and therefore, the two single row ball bearings 12A and 12B interfere with the sleeve 11 with the flange portions 14A and 14B, respectively. Without causing them, the respective bearing portions 13A and 13B can be sufficiently press-fitted into the sleeve 11 until their tips contact each other.
[0012]
3 and 4 show one form of the press-fitting device used for the press-fitting, and includes a base 20 and a press-fitting jig 21 disposed above the base 20 so as to be movable up and down. At the time of press-fitting, first, as shown in FIG. 3, the sleeve 11 is placed on the base 20, and after the single-row ball bearing 12 </ b> A is aligned with the upper opening of the sleeve 11, the press-fitting jig 21 is moved downward. . Then, receiving the pressing force from the press-fitting jig 21, the bearing portion 13A of one single row ball bearing 12A is gradually press-fitted into the sleeve 11, and finally the flange portion 14A comes into contact with the upper end of the sleeve 11 and press-fitted. End. The tip of the press-fitting jig 21 may be flat, but a relief portion 21a may be provided on the center side of the tip so as to press only the outer ring 16 as shown.
[0013]
Next, the sleeve 11 is inverted, and the sleeve 11 is placed on the base 20 via the single-row ball bearing 12A that has been press-fitted as shown in FIG. Then, after the other single row ball bearing 12B is aligned with the upper opening of the sleeve 11, the press-fitting jig 21 is moved downward. Then, the bearing portion 13B of the other single-row ball bearing 12B is gradually press-fitted into the sleeve 11 under the pressing force from the press-fitting jig 21. Finally, the tip of the bearing portion 13B first enters the sleeve 11 first. The press-fit end comes into contact with the tip of the bearing portion 13A of the one single-row ball bearing 12A that has been press-fitted. At this time, as described above, the length L _S of the sleeve 11 is equal to or slightly shorter than the sum of the lengths L _A and L _B of the bearing portions 13A and 13B of the single row ball bearings 12A and 12B. (FIG. 2), the flange portion 14B of the other single-row ball bearing 12B does not interfere with the upper end of the sleeve 11, and a slight gap is secured between them. In this press-fitting, the other single-row ball bearing 12B is placed on the base 20 without reversing the sleeve 11 after the assembly of the single-row ball bearing 12A, and the sleeve 11 is placed thereon. Alignment may be performed and press-fitting may be performed just in an upside down arrangement with respect to FIG.
[0014]
The bearing device 10 is usually press-fitted and fixed to the eccentric shaft 2 and positioned so that the sleeve 11 abuts against the piston P of the pump as shown in FIG. This press-fitting is performed by pressing the inner ring 15 of each single-row ball bearing 12A, 12B with a press-fitting jig. As described above, the length L _S of the sleeve 11 is the bearing portion of each single-row ball bearing 12A, 12B. 13A, sliding 13B of length L _a, since it is set to be slightly shorter than that sum or equivalent L _B, each of the single row ball bearings 12A, 12B is on the eccentric shaft 2 remains in contact with the tip Thus, the bearing device 10 can be smoothly assembled to the eccentric shaft 2 without being deformed.
[0015]
When the output shaft 1 rotates under the above-described assembled state, the bearing device 10 moves circularly around the axis of the output shaft 1 integrally with the eccentric shaft 2, and the piston P follows this movement. , Perform reciprocating movement as indicated by arrows A-A '. Thus, according to the bearing device 10, the two single row ball bearings 12A and 12B are closely fitted and arranged in the sleeve 11 (with the respective bearing portions 13A and 13B in contact with each other). Therefore, the load is evenly transmitted to the two single row ball bearings 12A and 12B via the sleeve 11, and therefore, even if a small one is selected as the single row ball bearings 12A and 12B, a sufficient load capacity can be obtained. It will be demonstrated. Particularly in the present embodiment, since bearings with flanges are used as the single-row ball bearings 12A and 12B, the flange portions 14A and 14B serve to regulate the press-fit end when the sleeve 11 is press-fitted. 11, each single row ball bearing 12A, 12B can be easily positioned, and the assemblability is improved. Further, since the flange portions 14A and 14B also function as stoppers for restricting relative movement between the single row ball bearings 12A and 12B and the sleeve 11, the coupling between the single row ball bearings 12A and 12B and the sleeve 11 is stabilized.
[0016]
In the above embodiment, the bearing portions 13A and 13B of the single row ball bearings 12A and 12B are press-fitted into the sleeve 11. Instead, the bearing portions of the single row ball bearings 12A and 12B are used. 13A and 13B may be temperature-fitted to the sleeve 11.
[0017]
Here, in the above embodiment, the single row ball bearings 12A and 12B with flanges are used. However, as shown in FIG. 5, the present invention uses general-purpose single row ball bearings 12'A and 12 'without flanges. B may be used. In this case, the total length L ′ _A , L ′ _B of each single-row ball bearing 12 ′ _A , 12 ′ _B is equal to or equal to the length L _S of the sleeve 11. Set to be slightly longer than.
[0018]
In the above embodiment, two single row ball bearings 12A and 12B are used. However, in the present invention, three or more single row ball bearings may be used. When a single row ball bearing is used, as shown in FIGS. 6 and 7, a single row ball bearing 12C without flange is added to the single row ball bearings 12A and 12B with flange, and this single row ball bearing without flange is added. 12C is arranged in the middle and is press-fitted and fixed in the sleeve 11. In this case, the total length of the lengths L _A and L _B of the bearing portion bearing portions 13A and 13B of the single row ball bearings 12A and 12B with flange and the total length L _C of the single row ball bearing 12C without flange is defined as the sleeve 11. It is set so as to be equal to or slightly longer than the length L _S.
[0019]
In the above embodiment, the application to the motion conversion mechanism for driving the piston type pump in the anti-lock brake system or the traction control system has been shown. Of course, it can be applied to various required fields.
[0020]
【The invention's effect】
As described above, according to the bearing device according to the present invention, it is possible to achieve both improvement in load capacity and downsizing without much cost increase, and the utility value is great. is there.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the structure of a bearing device according to an embodiment of the present invention.
FIG. 2 is an exploded sectional view of the bearing device.
FIG. 3 is a sectional view showing a schematic structure of a press-fitting device for assembling the bearing device and an embodiment of press-fitting by the device.
4 is a cross-sectional view showing an embodiment of press-fitting by the press-fitting device shown in FIG.
FIG. 5 is a sectional view showing a structure of a bearing device according to another embodiment of the present invention.
FIG. 6 is a cross-sectional view showing the structure of a bearing device according to still another embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a structure of a bearing device according to still another embodiment of the present invention.
FIG. 8 is a cross-sectional view showing a structure of a conventional bearing used for driving a piston type pump and its usage.
9 is a cross-sectional view showing the structure of another bearing that can replace the bearing shown in FIG.
10 is a cross-sectional view showing a structure of still another bearing instead of the bearing shown in FIG.
FIG. 11 is a cross-sectional view showing a structure of still another bearing instead of the bearing shown in FIG. 8;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Motor output shaft 2 Eccentric shaft 10 Bearing apparatus 11 Sleeve 12A, 12B Single row ball bearing 13A, 13B Bearing part 14A, 14B Flange part 15 Inner ring 16 Outer ring 17 Ball (ball)
21 Press-fit jigs 12'A, 12'B, 12C Single row ball bearings without flange P Piston of pump

Claims (2)

A bearing device used in a motion conversion mechanism that converts rotation of the output shaft of a motor including an output shaft having an eccentric shaft connected thereto into piston reciprocating motion,
A plurality of single-row ball bearings are in close contact with each other and flanged with single-row ball bearings positioned at both ends in the sleeve, and are fitted onto the eccentric shaft, and the sleeve is in contact with the piston. A bearing device characterized by being combined.   The bearing device according to claim 1, wherein the flange of the single row ball bearing is disposed in contact with or slightly away from the end face of the sleeve.

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