JP2010002043A - Bearing for cross shaft coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing for a cross shaft coupling, providing no concern of wrong combination, and restraining looseness without increasing torque. <P>SOLUTION: This bearing for a cross shaft coupling is interposed between a shaft part of a cross shaft and a round hole of a yoke, the inner peripheral surface of a shell cup pressed in the round hole is taken as an outer raceway surface for a roller, and the outer peripheral surface of the cross shaft is taken as an inner raceway surface for the roller. A diameter difference is made between the cup bottom side and the counter-cup bottom side in the outer raceway surface, and a radial clearance between the roller train at the cup bottom side and the cross shaft is set larger than that between the roller train at the counter-cup bottom side and the cross shaft. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a bearing for a cross joint used for a steering device, a propeller shaft, or the like of an automobile.

  A cross shaft joint is a shaft joint that uses a cross shaft (also referred to as a spider or a cross pin), and is sometimes called a hook joint, a cross joint, a cardan joint, or the like. As shown in FIG. 3, the cross shaft joint includes a pair of yokes 10, a cross shaft 16, and four bearings 20. Each yoke 10 integrally has a pair of arms 12 parallel to each other, and each arm 12 has a round hole 14 formed therein. The round holes 14 of the pair of arms 12 are aligned coaxially. The cross shaft 16 has four shaft portions 18 arranged radially at intervals of 90 degrees, and each shaft portion 18 is rotatably supported in the round hole 14 of the yoke 10 via a bearing 20.

  As shown in an enlarged view in FIG. 4, the bearing 20 is a so-called closed-end shell needle roller bearing, and includes a shell cup 22 and a plurality of needle rollers 30. As can be seen from FIG. 5 showing a state in which only the shell cup 22 is press-fitted into the round hole 14 of the yoke 10, the shell cup 22 has a cylindrical portion 24 and a bottom portion (also referred to as the cup bottom) located at one end of the cylindrical portion 24. 26) and an inward flange 28 located at the other end of the cylindrical portion 24. The outer peripheral surface of the cylindrical portion 24 fits with the inner peripheral surface of the round hole 14 of the yoke 10. The inner peripheral surface of the cylindrical portion 24 becomes an outer raceway surface for the needle rollers 30. The cylindrical outer peripheral surface of the shaft portion 18 of the cross shaft 16 becomes an inner raceway surface for the needle rollers 30. A seal 32 is provided to prevent the lubricant filled in the bearing 20 from leaking and preventing water and foreign matter from entering from the outside. The seal 32 is obtained by vulcanizing and bonding rubber to a core metal. A core metal part is attached to the cross shaft 16 and a lip is elastically adhered to the shell cup 22.

In general, in a vehicle steering apparatus, for example, a cross joint is interposed between an upper shaft and a lower shaft of a steering shaft so that torque is transmitted at a predetermined bending angle. FIG. 6 shows an example of a steering device having three cross joints J1, J2, and J3.
International publication pamphlet WO03 / 064877

  When a cross joint is used in a steering device, there are problems of rattling and noise. As a cause of the rattling and the sound, there is a rattling of the cross joint. The conventional cross shaft joint bearing has a portion that is press-fitted into the round hole 14 of the yoke 10 and a portion that is not press-fitted when viewed in the axial direction. Therefore, a radial clearance between the bearing 20 and the shaft portion 18 of the cross shaft 16 is provided. It is inevitable that becomes non-uniform in the axial direction. When the cross shaft 16 is assembled, the axial center (on the bottom side of the cup) of the cross shaft 16 is not press-fitted into the yoke 10, so that the radial clearance is larger than the portion of the cup bottom press-fitted into the yoke 10. It gets bigger.

  In the conventional structure, when the radial clearance between the bearing and the shaft portion of the cross shaft is a negative clearance in order to suppress rattling, the torque increases and the steering operability decreases.

  Patent Document 1 proposes that the rollers are in a double row, and the diameter difference between the rollers in one row and the rollers in the other row is set to 0.002 to 0.010 mm. However, the bearing structure described in Patent Document 1 is a type in which the roller falls off, and since two types of rollers that cannot be visually distinguished are incorporated, misassembly is inevitable. Moreover, since two types of rollers are required, it is inferior in terms of management and cost, and is not suitable for practical use.

  An object of the present invention is to suppress rattling without increasing the torque of the bearing for a cross joint while eliminating the above-mentioned problems.

  In this invention, the outer raceway surface of the shell cup is provided with a diameter difference between the cup bottom side and the anti-cup bottom side, and the radial clearance between the bearing and the cross shaft is set such that the cup bottom side row> the anti-cup bottom side row. Solved the problem. That is, the bearing for the cross shaft joint of the present invention is interposed between the shaft portion of the cross shaft and the round hole of the yoke, and the inner peripheral surface of the shell cup press-fitted into the round hole is used as the outer raceway surface for the roller. The outer peripheral surface of the cross shaft is an inner raceway surface for the roller, and the outer raceway surface is provided with a diameter difference between the cup bottom side and the anti-cup bottom side. The radial clearance is made larger than the radial clearance between the roller array on the bottom side of the cup and the cross shaft.

  More specifically, on the cup bottom side, the radial clearance between the bearing and the cross shaft is set to 0, and the mounting is performed with the clearance minimized. On the bottom side of the cup, the radial clearance between the bearing and the cross shaft is set as a negative region and attached with a preload (tightening allowance). That is, the radial clearance is made different between the cup bottom side row and the anti-cup bottom side row of one bearing. As a result, when the cross shaft is assembled, the roller row on the axial center side (the anti-cup bottom side) of the cross shaft that is not press-fitted into the round hole of the yoke is fitted with a preload (tightening allowance). A structure that suppresses In addition, the roller row on the cup bottom side that is press-fitted into the round hole of the yoke applies a load and sets a radial clearance with the cross shaft to zero in order to reduce torque.

  According to a second aspect of the present invention, in the cross shaft joint bearing according to the first aspect, the rollers are arranged in a double row.

  According to a third aspect of the present invention, in the bearing for the cross joint according to the second aspect, the rollers in one row and the rollers in the other row are the same size.

  According to a fourth aspect of the present invention, in the cross joint joint bearing of the second aspect, the inscribed circle diameter is different between the rollers in one row and the rollers in the other row.

  According to a fifth aspect of the present invention, in the cross joint joint bearing according to any one of the second to fourth aspects, a side plate is disposed between the roller rows. The cup row side roller row 30a and the anti-cup bottom side roller row 30b have different raceway diameters and therefore have different circumferential speeds. Therefore, when both contact, there exists a possibility that smooth rotation may be inhibited. Therefore, by arranging a side plate between the two so that the roller row 30a on the cup bottom side and the roller row 30b on the anti-cup bottom side do not contact each other, smooth rotation is possible respectively.

  According to the present invention, the outer raceway surface has a diameter difference between the cup bottom side and the anti-cup bottom side, and the radial clearance between the roller row on the cup bottom side and the cruciform shaft is set to the roller row on the anti-cup bottom side and the cruciform shaft. Since it is larger than the radial clearance, the following effects can be obtained. That is, on the side of the bottom of the cup that is not press-fitted into the round hole of the yoke, the radial clearance between the roller array and the cross shaft is smaller than the bottom of the cup. For example, by setting the radial clearance to a negative region, The rattling is suppressed. On the cup bottom side that is press-fitted into the round hole of the yoke, the radial clearance between the roller array and the cross shaft is larger than that on the side opposite to the cup bottom. Therefore, in the steering device using the cross shaft joint according to the present invention, smooth steering performance can be obtained, and the occurrence of abnormal noise can be suppressed.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The configuration of the cross joint is as described above with reference to FIGS. 3 to 5, and the same reference numerals denote the same parts or parts throughout all the drawings.

  FIG. 1 (A) shows a cross section of the bearing portion of the cross joint, and FIG. 1 (B) is a further enlarged view thereof. FIG. 2 is a sectional view showing only the shell cup 22 press-fitted into the round hole 14 of the arm 12 of the yoke 10.

  As is well understood from FIGS. 1B and 2, the outer peripheral surface of the cylindrical portion 24 of the shell cup 22 is fitted to the round hole 14 in a part of the axial direction (cup bottom side) as in the conventional case. . The inner peripheral surface of the outer raceway surface 30 is not flush, and a diameter difference is provided between the cup bottom side and the anti-cup bottom side. That is, the cup bottom side is the large diameter portion 24a, and the anti-cup bottom side is the small diameter portion 24b. Two rows of roller rows 30a and 30b are arranged corresponding to the large diameter portion 24a and the small diameter portion 24b. The rollers 30 in each row are assembled in a full roller state, and all have the same size. If the diameter difference of a raceway surface is illustrated, it will be about 0.010-0.040 mm although it depends on a bearing size. Therefore, the difference between the inscribed circle diameter of the roller row 30a and the inscribed circle diameter of the row 30b is also about 0.010 to 0.040 mm. As an example of the size of the roller 30, when the bearing 20 is called 24, a roller diameter of 2 mm, a roller length of 10 mm, and a number of rollers of 30 to 32 are appropriate. The material of the roller 30 is generally JIS standard SUJ1 to SUJ5 bearing steel.

  Provide different diameters by changing the inner diameter of the outer raceway cup bottom side and the non-cup bottom side, incorporate both rows (double row) of the same diameter roller, and set the radial clearance between the bearing and the cross shaft to the cup bottom side row. > An anti-cup bottom side row. The anti-cup bottom side row is mounted in a state where the radial clearance between the bearing and the cross shaft is a negative region and preload is applied. The cup bottom row is mounted with the radial clearance between the bearing and the cross shaft set to 0, and the clearance is minimized.

  As a result, when the cross shaft 16 is assembled to the yoke 10, the center side in the axial direction (the anti-cup bottom side) of the cross shaft 16 that is not press-fitted into the round hole 14 of the arm 12 is given a preload and tightened. A structure that fits and suppresses rattling. On the other hand, with respect to the cup bottom side that is press-fitted into the round hole 14, a radial clearance with the cross shaft 16 is aimed at zero in order to apply a load and reduce torque. In order to express this, in FIG. 1, the clearance between the shaft portion 18 of the cross shaft 16 and the rolling surface of 30 a is exaggerated.

  The outer raceway surfaces (24a, 24b) have a difference in diameter, and the roller diameter is the same for both the cup bottom roller row 30a and the anti-cup bottom roller row 30b. The inscribed circle diameter is different from that of the roller row 30b on the cup bottom side.

  As shown in the figure, a side plate 34 may be disposed between the roller rows on the cup bottom side and the anti-cup bottom side. The cup row side roller row 30a and the anti-cup bottom side roller row 30b have different raceway diameters and therefore have different circumferential speeds. Therefore, when both contact, there exists a possibility that smooth rotation may be inhibited. Therefore, by arranging a side plate between the two so that the roller row 30a on the cup bottom side and the roller row 30b on the anti-cup bottom side do not contact each other, smooth rotation is possible respectively. Examples of the material of the side plate 34 include steels such as SPC and SCM. Although the side plate 34 shaped like a plain washer is shown in FIG. 1B, other arbitrary shapes may be used.

  One cross shaft joint has four bearings 20, but the cross shaft joint of the present embodiment is applied to one or more places.

  The steering device employing the bearing 20 described here may be of any type such as a hydraulic power steering, an electric power steering, or the like.

(A) is the longitudinal cross-sectional view of the bearing for cross joints which shows an Example, (B) is the elements on larger scale of FIG. 1 (A). It is a longitudinal cross-sectional view which shows the assembly | attachment process of the bearing of FIG. It is a partially broken front view of the cross joint which shows the prior art. FIG. 4 is a partially enlarged view of FIG. 3. It is a longitudinal cross-sectional view which shows the assembly | attachment process of the bearing of FIG. It is a side view of a steering device.

Explanation of symbols

10 Yoke 12 Arm 14 Round hole 16 Cross shaft 18 Shaft portion 20 Bearing 22 Shell cup 24 Cylindrical portion 24a Large diameter portion 24b Small diameter portion 26 Bottom portion 28 Inward flange 30 Roller 32 Seal 34 Side plate

Claims (5)

  An inner peripheral surface of the shell cup that is interposed between the shaft portion of the cross shaft and the round hole of the yoke and is press-fitted into the round hole is an outer raceway surface for the roller, and the outer peripheral surface of the cross shaft is for the roller In the inner raceway surface, the outer raceway surface is provided with a diameter difference between the cup bottom side and the anti-cup bottom side, and a radial clearance between the cup bottom roller row and the cross shaft is set to the anti-cup bottom side roller row. A bearing for a cross joint that is larger than the radial clearance with the cross shaft.   The bearing for a cross shaft joint according to claim 1, wherein the rollers are arranged in a double row.   The bearing for a cross joint according to claim 2, wherein the rollers in one row and the rollers in the other row have the same size.   The bearing for a cross shaft joint according to claim 2, wherein the inscribed circle diameters of the rollers in one row and the rollers in the other row are different.   The bearing for a cross shaft joint according to any one of claims 2 to 4, wherein a side plate is disposed between the roller rows.

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