JP3950697B2 - Intermediate shaft of steering device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intermediate shaft of a steering device.
[0002]
[Background Art and Problems to be Solved by the Invention]
For example, in a steering device for a truck, a steering shaft for a steering column attached to the driver's cab and a steering device attached to the chassis can be extended and retracted in order to cablt down the truck cab forward with respect to the chassis. Some are connected via an intermediate shaft (hereinafter also referred to as an intermediate shaft).
[0003]
In such an intermediate shaft, the shaft member is fitted into the tubular member, and the shaft member and the tubular member can be integrally rotated and relatively slidable in the axial direction. Typically, a bottom portion is provided at one end of the cylindrical member, and a solid shaft member is passed through the open end of the other end. In addition, a dust seal is provided between the shaft member and the cylindrical member so that foreign matter such as rainwater and mud does not enter, and the inside of the cylindrical member is sealed.
For this reason, when the intermediate shaft is contracted, the air pressure in the cylindrical member is increased, and if the pushed-in shaft member is made free, the shaft member may be rebounded by the air pressure. Further, when the internal pressure of the cylindrical member is increased, some air can be expected to escape through the lip portion of the dust seal, but it is insufficient.
[0004]
Accordingly, an object of the present invention is to provide an intermediate shaft of a steering device that can solve the above technical problem and can sufficiently secure a flow amount of air inside and outside during expansion and contraction while suppressing intrusion of foreign matter.
[0005]
[Means for Solving the Problems and Effects of the Invention]
The invention according to claim 1 is a cylindrical member whose one end is closed and the other end is opened, and a shaft member which is fitted so as to be relatively slidable in the axial direction through the opening end of the cylindrical member and rotates integrally with the cylindrical member. an intermediate shaft of a steering apparatus having comprises a passageway extending to the axis axially allowing flow of outside air has an opening in the cylindrical member at both ends of the member, the inner cylinder member at both ends of the shaft member At the inserted end portion , one opening of the passage is formed so as to face the inside of the cylindrical member, and a ventilation valve made of an elastic body capable of forming a through hole for ventilation is provided in this one opening, and this elastic vent valve comprising a body, by forming the ventilation holes by looking elastic deformation when a difference occurs in the air pressure in the passage of air and the shaft member in the tubular member, the outflow of the grease to be retained in the tubular member Air flow between the passage and the cylinder member It is not characterized and Turkey. If there is a passage extending in the axial direction, it is possible to secure a large amount of air flow while suppressing foreign matter from entering the cylindrical member. As a result, the intermediate shaft can be expanded and contracted smoothly.
Further, when the intermediate shaft is contracted, it is possible to prevent grease from entering the passage from the inside of the cylindrical member. Therefore, there is no shortage of the amount of grease to be supplied where it is needed.
[0007]
The invention according to claim 2, Oite to claim 1, comprising a check valve that allows air in the cylinder member is discharged to the outside, the check valve, the open end of the tubular member It is characterized by comprising a dust seal having a lip that is disposed and slidably contacts the outer periphery of the shaft member. According to the present invention, since the circulation of the air inside and outside the cylindrical member can be secured through the above-described passage, even if a normal dust seal is used, the lip functions as a check valve that prevents the inflow of air. be able to. As a result, it is possible to enhance the effect of the dust seal that prevents the entry of foreign matter.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a steering device and an intermediate shaft of a reference example will be described with reference to the drawings. FIG. 1 is a schematic side view showing a schematic configuration of a steering device of a reference example .
The steering device 1 includes a steering shaft 3 that transmits the movement of the steering wheel 2 to steer a wheel (not shown), and a steering column 4 that rotatably supports the steering shaft 3 through the inside. is doing. A steering wheel 2 is connected to one end 5 of the steering shaft 3. A steering mechanism 10 including a pinion, a rack shaft and the like is connected to the other end portion 6 of the steering shaft 3 via universal joints 7 and 8 and an intermediate shaft 9 so as to be integrally rotatable. When the steering wheel 2 is rotated, the rotation is transmitted to the steering mechanism 10 via the steering shaft 3, the universal joints 7, 8, the intermediate shaft 9 and the like, and thereby the steering wheel can be steered.
[0010]
The intermediate shaft 9 includes a tubular member 11, a shaft member 12 fitted to the tubular member 11, and a dust seal 13 that seals between the shaft member 12 and the tubular member 11. The cylindrical member 11 and the shaft member 12 are arranged coaxially with the central axis of the intermediate shaft 9. The intermediate shaft 9 can rotate integrally with the cylinder member 11 and is disposed on the steering mechanism 10 side, and the other universal joint can be rotated integrally with the shaft member 12 and disposed on the steering column 4 side. 7. As shown in part in FIG. 2, each of the universal joints 7 and 8 is configured by connecting a pair of yokes 14 having a fork shape via a cross shaft 15.
[0011]
Please refer to FIG. 2 and FIG.
The cylindrical member 11 includes a cylindrical main body 30 extending along the axial direction of the intermediate shaft 9 (hereinafter, also simply referred to as an axial direction; see arrow S), and one end of the main body 30 provided on the main body 30. It has a disk-shaped bottom 31 that closes the inside, and a yoke 14 of one universal joint 8 that is disposed adjacent to and corresponds to the bottom 31. One end 35 of the cylindrical member 11 is provided with a yoke 14, a bottom 31, and a portion of the main body 30 adjacent to the yoke 14. Each of these parts 30, 31, and 14 may be formed integrally, or those formed separately may be fixed to each other by welding or the like. The fitting portion between the cylindrical member 11 and the shaft member 12 is lubricated inside the cylindrical member 11 by the bottom portion 31, the main body portion 30, and the end portion 41 of the shaft member 12 fitted to the main body portion 30. An accommodating chamber 16 for accommodating the grease for the purpose is defined. At the other end 34 of the cylindrical member 11, an end portion 32 of the main body portion 30 is opened, and a fitting portion is formed in a predetermined range in the axial direction from the end portion 32 (also referred to as an opening end 32). This fitting portion is fitted with the fitting portion of the shaft member 12.
[0012]
The shaft member 12 has a main body portion 40 that is hollow and extends in the axial direction, and a yoke 14 that is fixed to the end portion of the main body portion 40 by welding and corresponding to the other universal joint 7. The end portion 41 of the shaft member 12 that is the inside of the cylindrical member 11 has a fitting portion of the main body portion 40. This fitting portion is fitted to the above-described fitting portion of the cylindrical member 11 through the open end 32 of the main body portion 30 of the cylindrical member 11 so as to be slidable in the axial direction, whereby the shaft member 12 and the cylindrical member 11 are Rotate together. The fitting portions of both the members 11 and 12 have, for example, a serration fitting structure or a spline fitting structure, and the shaft member 12 and the cylindrical member 11 can rotate integrally and can slide relative to each other in the axial direction. The structure of can be used.
[0013]
The rotational force from the steering shaft 3 is transmitted to the steering mechanism 10 via the universal joint 7, the shaft member 12, the cylindrical member 11, and the universal joint 8. Moreover, the intermediate shaft 9 can be expanded and contracted in the axial direction by the relative sliding of the shaft member 12 and the cylindrical member 11.
In particular, the reference example is configured as follows so that the intermediate shaft 9 can be smoothly expanded and contracted. That is, the shaft member 12 is provided with a passage 50 extending in the axial direction having openings 51 and 52 at both end portions 41 and 42 of the shaft member 12 and allowing outside air to flow into the cylindrical member 11.
[0014]
The passage 50 continuously passes through the main body portion 40 of the shaft member 12 and the yoke 14 of the universal joint 7 adjacent to the main body portion 40 in the axial direction. The passage 50 has one opening 51 facing the inside of the cylindrical member 11, the other opening 52 facing the outer OU of the intermediate shaft 9, and a hole extending linearly along the axial direction, connecting both the openings 51, 52 to allow ventilation. And an intermediate portion 53.
With such a passage 50 extending in the axial direction, foreign matter from the external OU can hardly pass through the passage 50. Therefore, the intermediate shaft 9 can be smoothly expanded and contracted as a result of ensuring a large amount of air flow while suppressing the entry of foreign matter into the cylindrical member 11. For example, there is no risk of so-called rebound.
[0015]
One opening 51 is formed at one end 41 of the shaft member 12 so as to face the inner part of the cylindrical member 11 with respect to the opening end 32 even when the shaft member 12 extends most from the opening end 32. For example, the main body 40 is disposed in a portion corresponding to the fitting portion of the shaft member 12. The end portion 41 of the shaft member 12 has an end surface of the main body portion 40 and an outer periphery of the main body portion 40 adjacent to the end surface. In this reference example , the opening 51 is formed on the end face.
[0016]
The other opening 52 is arranged at the other end 42 of the shaft member 12 in the axial direction. The end portion 42 has the corresponding yoke 14 described above that becomes a part of the shaft member 12 and the outer periphery of the main portion 40 adjacent to the yoke 14. The yoke 14 includes a pair of support portions 56 that face each other and support the cross shaft 15, and a connection portion 57 that connects the support portions 56 to each other. For example, in the present reference example , the opening 52 is formed in the connecting portion 57 of the yoke 14, but may be formed at the end portion 42 of the shaft member 12, for example, on the outer periphery of the main body portion 40. In short, the opening 52 only needs to be opened so that the outside air can be circulated.
[0017]
The cross-sectional areas of both openings 51 and 52 are made smaller than the cross-sectional area of the intermediate portion 53 in the cross section cut in the axial direction. As described above, by reducing at least one of the openings 51 and 52, foreign substances from the outside can be more difficult to reach the inside of the cylindrical member 11. Further, by making the opening 51 small, it is possible to prevent the grease from entering the passage 50 from the accommodation chamber 16. In addition, since the intermediate portion 53 may be large, the passage 50 can be easily formed.
[0018]
In this way, in the reference example , the entry of the foreign matter can be suppressed by reducing both the openings 51 and 52, so that the passage 50 is always open to the inside of the cylindrical member 11 and the outer OU of the intermediate shaft 9, The structure has been simplified.
The intermediate shaft 9 has a check valve 18 that allows only the air in the cylindrical member 11 to be discharged to the external OU and prevents the air in the external OU from flowing into the cylindrical member 11. In particular, the check valve 18 of this reference example includes the dust seal 13 having a lip 58 that is disposed at the opening end 32 of the cylindrical member 11 and that is in sliding contact with the outer periphery 43 of the main body portion 40 of the shaft member 12. Since the flow of air inside and outside the cylindrical member 11 can be ensured through the passage 50 described above, the lip 58 functions as the check valve 18 that prevents the inflow of air even when the dust seal 13 is a normal dust seal. be able to. As a result, it is possible to enhance the effect of the dust seal 13 that prevents foreign matter from entering.
[0019]
The dust seal 13 seals between the outer periphery 43 of the shaft member 12 and the main body portion 30 of the cylindrical member 11, and prevents the grease in the cylindrical member 11 from entering the inside of the cylindrical member 11 from the external OU. Do not leak outside.
The dust seal 13 is formed in an annular shape by an elastic member such as a rubber material, and has a substantially groove shape in cross section. The groove shape opens toward one side in the axial direction, and prevents air and other foreign matter from flowing. It is shaped to allow distribution to the external OU. The inner peripheral portion of the dust seal 13 has the lip 58 described above. The outer periphery of the dust seal 13 is fixed to the cylindrical member 11 by a cover 19. The inner peripheral portion and the outer peripheral portion of the dust seal 13 are connected to each other at one end in the axial direction by a disk-shaped connecting portion. The lip 58 of the inner peripheral portion 13 extends outward in the axial direction from the inner periphery of the connecting portion.
[0020]
When the intermediate shaft 9 is extended, the empty space in the cylinder member 11 is expanded, the air pressure becomes lower than the external air pressure, the pressure applied to the back surface of the lip 58 is increased, and the lip 58 has an outer periphery 43 of the shaft member 12. Is pressed relatively strongly against and makes close contact. As a result, intrusion of air and foreign matters from the outside is prevented. Further, as the inside of the cylindrical member 11 becomes lower in pressure than the outside, outside air flows into the inside of the cylindrical member 11 from the opening 52 through the passage 50 as shown in FIG. 3A (showing the flow of outside air). (See arrow OA).
[0021]
On the other hand, when the intermediate shaft 9 is contracted, the air pressure in the cylinder member 11 becomes higher than the air pressure of the external OU, and the air flows from the opening 51 to the external OU through the passage 50 (see arrow IB indicating the flow of the internal air). . At the same time, the lip 58 is urged outward in the radial direction by the air pressure, and a slight gap is formed between the lip 58 and the outer periphery 43 of the shaft member 12, and through this gap, as shown in FIG. Then, air is caused to flow out from the cylinder member 11 to release the high pressure (see arrow IA indicating the flow of the internal air). At this time, as the shaft member 12 tries to enter the cylindrical member 11, even if an external foreign matter tries to enter through the gap, the intrusion is prevented by the air blown out from the gap. In addition, the above-mentioned gap is small and only opens momentarily, and the seal lip 58 is generally pressed against the outer periphery 43 of the shaft member 12 to prevent foreign matter from entering.
[0022]
In the first embodiment of the present invention, instead of the intermediate shaft 9 described above, as shown in FIGS. 4 and 5, the intermediate shaft 20 is provided. In the following description, differences from the reference example will be mainly described, and the same portions will be denoted by the same reference numerals and description thereof will be omitted.
The intermediate shaft 20 includes the above-described cylinder member 11, shaft member 21, dust seal 22, and vent valve 23.
The shaft member 21 is used instead of the shaft member 12 described above. In the shaft member 12, the opening 51 is approximately the same size as the intermediate portion 53. The shaft member 12 is provided with a vent valve 23 in the opening 51 of the passage 50 facing the inside of the cylindrical member 11. A fitting hole 44 as an attachment structure for attaching the vent valve 23 is formed adjacent to the opening 51 and close to the storage chamber 16 in the axial direction. The ventilation valve 23 is attached to the fitting hole 44 via the attachment member 24. The fitting hole 44 is continuous with the opening 51 and has the same inner diameter as that of the intermediate portion 53 of the passage 50.
[0023]
The ventilation valve 23 can circulate air between the passage 50 and the cylindrical member 11 while suppressing the outflow of grease stored in the cylindrical member 11. By providing the vent valve 23 in the opening 51, it is possible to prevent grease from entering the passage 50 from the inside of the cylindrical member 11 when the intermediate shaft 20 is contracted. Therefore, there is no shortage of the amount of grease to be supplied to a required portion such as a fitting portion between the cylindrical member 11 and the shaft member 12. Further, if the ventilation valve 23 is provided in the passage 50, it is possible to reliably prevent foreign matter from entering through the passage 50.
[0024]
The ventilation valve 23 is an integrally molded product made of only an elastic material such as synthetic rubber or natural rubber, and has a flange-like engagement at both axial ends of a cylindrical body in which a ventilation through hole 61 is formed at the center. The portion 60 has a formed shape. The ventilation valve 23 is attached to the attachment member 24 by fitting the central portion of the ventilation valve 23 excluding the locking portions 60 at both ends into fitting through holes 62 formed in the attachment member 24. In the state before the mounting, as shown in FIG. 5B, the outer diameter dimension DA of the central portion of the vent valve 23 is larger than the inner diameter dimension of the mounting through hole 62 of the mounting member 24, and the mounting member of the vent valve 23 In the attached state to 24, the through-hole 61 for ventilation is configured to be elastically closed by deformation of the elastic material.
[0025]
The vent valve 23 uses the deformation of the elastic body only when a differential pressure is generated between the air pressures on both sides of the vent valve 23. The vent valve 23 can slightly open the vent hole 61 and allow only air to flow in both directions. Prevent grease from passing through. Thereby, the grease in the cylindrical member 11 is not sucked out, and the atmospheric pressure in the cylindrical member 11 does not increase.
The dust seal 22 is used in place of the dust seal 13, and is configured to prevent the flow of foreign matter and air. For example, even if it does not have a lip, a known configuration can be used. A dust seal 13 may be used.
[0026]
By the way, in the conventional intermediate shaft, there is one in which a vent valve is arranged at the bottom of the cylindrical member. Typically, in the intermediate shaft that is in the standing state, the cylindrical member is disposed below the shaft member. In this case, if grease accumulates at the bottom of the cylindrical member, there is a concern that the ventilation valve at the bottom is blocked. On the other hand, in the embodiment of the present invention, since the passage 50 is provided in the shaft member 12 above the storage chamber 16, even if grease accumulates in the bottom 31 of the cylindrical member 11, the passage 50 is not blocked, There is no risk that air permeability will be reduced.
[0027]
In another reference example of the present invention , an intermediate shaft 25 is provided in place of the intermediate shaft 9 as shown in FIG. The intermediate shaft 25 has the cylinder member 11, the shaft member 26, and the dust seal 22 described above. The intermediate shaft 25 is obtained by omitting the vent valve 23 in the first embodiment and providing an opening 51 in substantially the same manner as in the reference example.
The shaft member 26 differs from the shaft member 12 in that the cross-sectional area of the opening 51 on the end 41 side is limited. The cross-sectional area of the opening 51 is a clearance 27 between the outer periphery 43 of the shaft member 12 and the inner periphery 36 of the main body portion 30 of the cylindrical member 11, that is, a clearance between the opposing fitting portions of the cylindrical member 11 and the shaft member 12. 27 is smaller than the cross-sectional area.
[0028]
Thus, with a simple configuration in which the opening 51 is made small, the grease does not escape from the inside of the cylindrical member 11 to the passage 50 while ensuring the air flow. Therefore, a sufficient amount of grease can be supplied where needed. Further, if the opening 51 has a smaller cross-sectional area than the gap 27, and if the opening 51 is disposed near the center of the end surface of the end portion 41 of the shaft member 12, grease can enter the passage 50. The effect to prevent can be acquired to such an extent that there is no problem practically, and it is preferable.
[0029]
As described above, according to each embodiment and reference example of the present invention, by providing the passage 50 in each of the shaft members 12, 21, and 26, a sufficient amount of air flow to the cylindrical member 11 is ensured to achieve smooth expansion and contraction. However, it is possible to prevent entry of foreign matter and lack of grease.
Note that the vent valve 23 of the first embodiment may be provided in the opening 51 of the passage 50 of the reference example, and the cross-sectional area of the opening 51 may be configured similarly to another reference example of the present invention . In addition, various modifications can be made within the scope of the claims of the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic diagram in a side view of a schematic configuration of a steering device of a reference example.
FIG. 2 is a side cross-sectional view of a main part of the intermediate shaft in FIG.
3 is a side view schematically showing the operation of the intermediate shaft in FIG. 1, in which (a) shows a state during expansion and (b) shows a state during contraction.
FIG. 4 is a side sectional view of a main part of an intermediate shaft of the steering device according to the first embodiment of the present invention.
5 is a side cross-sectional view of the vent valve of the intermediate shaft shown in FIG. 4, where (a) shows a state attached to the attachment member, and (b) shows a state before attachment to the attachment member.
6 is a front cross-sectional view of a main part of an intermediate shaft of a steering device according to another reference example of the present invention, showing a portion corresponding to the AA cross section of FIG. 2;

Claims (2)

It is an intermediate shaft of a steering device having a cylindrical member having one end closed and the other end opened, and a shaft member that is fitted in an axial direction through the open end of the cylindrical member so as to be relatively slidable in the axial direction. And
A passage extending in the axial direction having openings at both ends of the shaft member and allowing outside air to flow into the cylindrical member,
One end of the passage is formed at the end portion inserted into the cylindrical member among the both ends of the shaft member so as to face the cylindrical member,
This one opening is provided with a ventilation valve made of an elastic body capable of forming a through hole for ventilation,
This ventilation valve made of an elastic body forms a through-hole for ventilation by elastic deformation only when a difference occurs between the air pressure in the cylinder member and the air pressure in the passage of the shaft member, so that the grease accumulated in the cylinder member can be reduced. An intermediate shaft of a steering device, wherein air is circulated between a passage and a cylindrical member while suppressing outflow. In the intermediate shaft of claim 1 Symbol mounting of the steering device, comprising a check valve that allows air in the cylinder member is discharged to the outside,
The check valve is an intermediate shaft of the steering device, and is composed of a dust seal having a lip disposed at the opening end of the cylindrical member and in sliding contact with the outer periphery of the shaft member.

Images