JPH06313448A - Clutch device - Google Patents

Abstract

PURPOSE:To improve the biting characteristics of engaging surfaces with engaging elements at a low temperature, in a clutch device for fitting an outer race to an input shaft and an output shaft and switching the rotational force transmission to the output shaft from the input shaft and the outer race by the engaging elements incorporated between the outer race and the output shaft. CONSTITUTION:The surface roughness of the surface of engaging elements 9, 9' composed of rollers and engaging surfaces 5, 6 so provided as to face an outer race 4 and an output shaft 3 are set within the range of 3S to 12S. The friction state of the contact part in the state where the engaging elements 9, 9' are engaged with the engaging surfaces 5, 6 is maintained well by the action of the surface roughness, thereby the low temperature biting characteristics is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch device and is used, for example, for switching the driving force of an electric power steering device.

[0002]

2. Description of the Related Art In an electric power steering system for a vehicle, when a steering wheel 40 is rotated as shown in FIG.
The sensor 45 detects the torque generated on the handle shaft 41 by the resistance from the wheel 49, and the motor 47 driven through the control device 46 rotates the pinion 43 of the handle shaft 41 via the speed reducer 48 and meshes with the pinion 43. The wheels 49 are steered via the rack 42.

In the above electric power steering system, the speed reducer is arranged so that the steering wheel 40 can be manually operated when an abnormality occurs in the drive system such as the control device 46, the motor 47, the speed reducer 48 and the like. The clutch device 1 is provided between the 48 and the pinion 43 to switch the drive path for the handle shaft 41.

As a clutch device 1 for mechanically switching such a drive path, one having a structure as shown in FIGS. 9 to 11 has been conventionally considered (Japanese Patent Application No. 63-23573).
No. 1).

This structure has an input shaft 52 arranged coaxially.
The outer ring 54 is fitted to the outer side of the output shaft 53, and the cage 57 integrated with the input shaft 52 and the output shaft 53 are provided between the engaging surfaces 55 and 56 formed on the facing surfaces of the output shaft 53 and the outer ring 54. A retainer 58 fixed to 53 is provided, and a pocket provided in each of the retainers 57 and 58 is provided with an engagement element 59 that engages with both engagement surfaces 55 and 56 by relative rotation of the outer ring 54 and the output shaft 53. An elastic material 60 that holds the engaging element 59 in a neutral state is incorporated.

Further, the input shaft 52 and the output shaft 53 are connected through a clearance X in the rotational direction, and the input shaft 52 and the output shaft 53 are connected.
In the meantime, a torque setting elastic member 61 that holds both of them in a neutral position in the rotational direction clearance X and that elastically deforms until the rotational direction clearance X disappears when a rotational force above a certain level is applied to the input shaft is incorporated. I'm out.

In the clutch device having the above structure, the input shaft 52
When the rotational force applied to the input shaft 52 is less than or equal to the set torque of the torque setting elastic member 61, the clutch does not operate and the rotational force is transmitted from the input shaft 52 to the output shaft 53. As described above, the engagement element 59 and the engagement surfaces 55 and 56 are engaged with each other to establish a clutch, and the rotational force from the outer ring 54 is transmitted to the output shaft 53.

[0008]

By the way, in the clutch device having the above structure, the inside of the clutch is lubricated with a lubricant such as oil, but the engaging surfaces 55, 56 and the engaging element 59 have a surface roughness of 1S to 2S. Since the surface of the outer ring 54 and the output shaft 53 has a low oil temperature and a high lubricant viscosity, the outer ring 54 and the output shaft 53 have engagement surfaces 55 and 56, and the surface of the engagement element 59. The lubrication state between the two becomes fluid lubrication having an extremely low coefficient of friction, which makes it difficult for the engagement surface and the engagement element to bite. Such difficulty in biting the engagement element causes a delay in the operation of the clutch or a disabling of the operation of the clutch, which causes a problem in the operation of the clutch device.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a clutch device that solves the above problems, improves the lubricity at low temperatures, and can maintain stable clutch operation.

[0010]

In order to solve the above-mentioned problems, the present invention sets the surface roughness of one or both of the engaging surfaces of the outer ring and the output shaft or the engaging portions of the engaging elements to 3S to 12S. It was set to the range.

[0011]

As described above, the surface roughness of the engaging portion is 3S-12.
By setting in the range of S, the contact state of the engaging portion can be maintained in a state where the friction coefficient is large, and the meshing characteristic at low temperature can be improved.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show a first embodiment of the clutch device according to the present invention.

As shown, the input shaft 2 is provided inside the outer ring 4.
The output shaft 3 is incorporated, and the peripheral surfaces of the input shaft 2 and the output shaft 3 are rotatably supported by the outer ring 4 via bearings 14.

A cylindrical cage 7 is incorporated between the outer ring 4 and the output shaft 3, and the closed end of the cage 7 is the input shaft 2.
Are integrally connected to.

A small-diameter shaft portion 15 is formed on the output shaft 3 at an end surface facing the closed end of the retainer 7, and the small-diameter shaft portion 1 is formed.
5 is inserted into a recess 16 provided at the closed end of the cage 7, and is rotatably supported via a bearing 17.

A cylindrical engagement surface 6 is provided on the inner diameter surface of the outer ring 4, while a polygonal planar engagement surface 5 is formed on the outer diameter surface of the output shaft 3. A wedge-shaped space 18 is formed between the engagement surfaces 5 and 6 so as to be gradually narrowed toward both ends in the circumferential direction.

The cage 7 is provided with a pocket 8 corresponding to the wedge-shaped space 18, and two engaging elements 9 and 9'made of rollers are incorporated in the pocket 8.

Between the two engaging elements 9 and 9 ', an elastic member 10 is incorporated which presses the engaging elements 9 and 9'in opposite directions to press the wall surfaces of the pocket 8 which face each other in the circumferential direction. Has been. Here, the surfaces of the engaging elements 9 and 9'and the output shaft 3
The surface roughness of the engaging surfaces 5 and 6 of the outer ring 4 is finished so that the surface roughness is in the range of 3S to 12S.

Further, as shown in FIG. 3, a pin 12 is provided on the outer diameter surface of the output shaft 3, and the pin 12 is inserted into a fitting hole 11 formed in the cage 7. This fitting hole 11
Is long in the circumferential direction of the cage 7, and has a fitting hole 11 and a pin 1
A clearance X in the rotational direction is formed between the pin 12, and the pin 12 is held at the neutral position of the clearance X in the rotational direction.
Torque setting elastic members 13 made of springs are incorporated on both sides of the pin 12. In this case, in the state where the pin 12 is held at the neutral position of the clearance X in the rotational direction, the engaging elements 9 and 9 ′ are in a state of not engaging with any of the narrowed portions at both ends of the wedge-shaped space 18.

The spring force of the torque setting elastic member 13 is
When a rotational force of a certain amount or more is applied to the input shaft 2, the torque setting elastic member 13 is deformed until the clearance X in the rotational direction disappears, and the retainer 7 and the output shaft 3 are determined to be engaged via the pin 12. There is.

The clutch device of the first embodiment has the above-mentioned structure. When this clutch device is used in an electric power steering device, as shown in FIG. 4, a handle shaft 41 having a handle 40 is used as an input shaft. 2 and the shaft 44 of the pinion 43 meshing with the rack 42 is connected to the output shaft 3. Further, a sensor 45 for detecting the twist of the handle shaft 41 is provided, and the rotation of the motor 47 driven by the sensor 45 through the control device 46 is transmitted to the outer ring 4 via the speed reducer 48 having a combination of gears.

While the clutch device 1 is assembled as described above, the inside of the clutch is filled with lubricating oil for lubrication.
Even when the oil temperature during operation is low and the lubricating viscosity is high, the engagement surface 5, 6 and the engagement element 9 cause the surface roughness of the engagement surface 5,
The friction coefficient between 6 and the engaging element 9 is maintained in a high state, and fluid lubrication does not occur. Therefore, the engagement surface and the engagement element are surely engaged with each other, and stable clutch operation can be performed.

FIGS. 5 to 7 show a second embodiment. This device, as shown in FIG. 5 and FIG.
And the respective opposing surfaces of the output shaft 22 through which the outer ring is inserted are formed by coaxial cylindrical surfaces 23 and 24 as engagement surfaces.
The inner retainer 25 is fixed to the cylindrical surface 24 and the outer retainer 26 is fixed to the input shaft 20.

A plurality of pockets 27, 28 are formed in the inner cage 25 and the outer cage 26 so as to face each other in the radial direction, and both ends of a sprag 29 as an engaging element are formed in each of the pockets 27, 28. Spring members 30 for inserting and holding the sprags 29 in a neutral state are attached to both sides of the pocket 28.

As shown in FIG. 7, the sprag 29 has cam surfaces 31 and 32 having arcuate surfaces 33 and 34, respectively, at both ends thereof. When the sprag tilts to either the left or right direction, each cam surface is formed. 31 and 32 come into contact with both cylindrical surfaces 23 and 24 to bring the clutch into engagement.

In this case, each cam surface 3 of the sprag 29 is
Nos. 1 and 32 are formed so that the surface roughness is in the range of 3S to 12S.

On the other hand, the input shaft 20 and the output shaft 22 are provided with an axial hole 35 which connects them to each other.
A torque setting elastic member 36 formed of a torsion bar is inserted into the shaft, and the torque setting elastic member 36 is fixed to the output shaft 22 of the input shaft 20 via a pin 37.

Further, the output shaft 22 has a square hole 38, and the input shaft 2
No. 0 is provided with a square shaft 39, and a rotation direction clearance X is provided between the square hole 38 and the square shaft 38.

In the above clutch device, as shown in FIG. 7, the sprag 29 is tilted to be in the clutch engageable state, and the rotation speed of the outer ring 21 rotating in the direction of arrow A from that state is the rotation speed of the output shaft 22. If the number exceeds the number, the cam surfaces 31 and 32 inside and outside of the sprag 29 will have their respective cylindrical surfaces 23 and 24.
And the torque load state is established.

On the other hand, when the outer ring 21 relatively rotates in the direction of arrow B in FIG. 7 from the clutch engaged state, the clutch idles and a gap is created between the cam surface 31 on the outer diameter side of the sprag 29 and the outer ring 21.

In the above structure, even if the viscosity of the lubricating oil increases at low temperature, the cam surfaces 31, 32 of the sprag 29 are
The surface roughness of the sprag 29 and the cylindrical surface 23,
The frictional state between 24 is maintained in good condition, and the sprag can be reliably bitten.

In the second embodiment, only the cylindrical surfaces 23, 24 or the cylindrical surfaces 23, 24 and the sprag 29 are used.
Surface roughness of both cam surfaces 31, 32 of 3S-12S
Even if it is set within the range, the same effect as above can be obtained.

[0033]

As described above, according to the present invention, the surface roughness of the engaging surface or the engaging element is set within a predetermined range so that the friction coefficient of the engaging portion is maintained at a constant value. It is possible to improve the low temperature bite characteristic of the clutch device and maintain the stable operation of the clutch device regardless of changes in the surrounding environment.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a clutch device according to a first embodiment.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an enlarged sectional view showing a main part of a clutch device.

FIG. 4 is a diagram showing an example in which the clutch device of the embodiment is used in an electric power steering device.

FIG. 5 is a vertical sectional front view showing a second embodiment.

FIG. 6 is a vertical side view of the above.

FIG. 7 is a cross-sectional view showing an enlarged main part of the above.

FIG. 8 is a diagram showing a schematic structure of an electric power steering device.

FIG. 9 is a vertical sectional front view showing a conventional example.

10 is a cross-sectional view taken along line XX of FIG.

11 is a sectional view taken along line XI-XI in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Clutch device 2 Input shaft 3 Output shaft 4 Outer ring 5,6 Engaging surface 7 Retainer 8 Pocket 9, 9'Engager 10 Elastic material 13 Torque setting elastic member 20 Input shaft 21 Outer ring 22 Output shaft 23, 24 Cylindrical surface 25 , 26 cage 27, 28 pocket 29 sprag 30 spring member 31, 32 cam surface 33, 34 arc surface 36 torque setting elastic member

Claims (1)

[Claims] 1. An outer ring is fitted on the outer side of an input shaft and an output shaft arranged coaxially, and an engaging surface is formed on each of the facing surfaces of the outer ring and the output shaft. In the pocket of the cage that has been inserted, an engaging element that engages with the engaging surfaces when the output shaft and the outer ring rotate relative to each other, and an elastic material that holds the engaging element in an unengaged state are provided. The output shaft and the output shaft are connected so that they can rotate together through the clearance in the rotation direction, and both shafts are held in the neutral position between the input shaft and the output shaft in the above-mentioned rotation direction clearance, and the input shaft rotates more than the set torque. In a clutch device incorporating a torque setting elastic member that elastically deforms when a force is applied until there is no clearance in the rotational direction, one or both of the above-mentioned engaging surfaces or engaging portions of an engaging element has a surface roughness of 3S. Clutch device characterized by being set in the range of Place