JP2673088B2 - Clutch device - Google Patents

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 more particularly to a clutch device suitable for an electric power steering device.

[0002]

2. Description of the Related Art FIG. 14 shows a general structure of an electric power steering apparatus. In this device, when the steering wheel 1 is rotated right or left, a torque is generated on the handle shaft 3 by resistance from the wheels 2. This torque is applied to the handle shaft 3
, And the motor 6 is driven through the control device 5. The drive shaft of the motor 6 is connected to the pinion 8 of the handle shaft 3 via a speed reducer 7, and the wheels 2 are steered via a rack 9 engaged with the pinion 8. As a result, the wheel 2 can be steered by a very slight steering force.

[0003]

However, in such an electric power steering apparatus, if an abnormality occurs in the drive system including the control device 5, the motor 6, and the speed reducer 7, and if these do not operate, the steering wheel is not operated. Since the speed reducer 7 and the motor 6 are connected to the shaft 3, there is a problem that the manual operation force of the steering wheel becomes excessively large and the steering becomes substantially impossible.

Therefore, a method is known in which the clutch device 10 is interposed between the speed reducer 7 and the pinion 8.

An electromagnetic clutch can be used as the clutch device 10 in this case, but it has a drawback that it is large in size to obtain a required transmission torque. Further, the use of the meshing clutch has a problem that a large force is required for aligning the meshing position and releasing the meshing condition under load.

An object of the present invention is to improve the reliability of transmission in which two inputs of a first drive shaft and a second drive shaft can be mechanically switched and transmitted to a driven shaft without external control. It is to provide a small clutch device having high cost.

[0007]

In order to solve the above problems, in the first invention, a circle provided at the end of the first shaft is used .
The end of the second shaft provided coaxially with the first shaft in the cylindrical cage.
Part, and insert a gap in the direction of rotation between the first and second shafts.
A torque transmission mechanism having
Is held in the neutral position, and torque exceeding the set torque is transmitted.
When elastically deformed elastically until the above-mentioned clearance in the rotation direction disappears
And a torque setting elastic member between the first shaft and the second shaft.
Provided outside the cage and driven to rotate by external power.
Inside the pocket formed on the cage
In addition, the first shaft and the second shaft are relatively rotated by a predetermined angle.
At this time, the outer peripheral surface of the second shaft is engaged with the inner peripheral surface of the outer ring to
Engagement member that transmits only rotation in the same direction as the first shaft to the second shaft
The torque transmission mechanism is rotated by the engaging member.
Of the outer ring while being held in the neutral position of the direction clearance.
The torque transmission mechanism does not engage the peripheral surface and the outer peripheral surface of the second shaft.
Engages the outer ring and the second shaft before engaging in the rotational direction
The adopted configuration is adopted.

In the second invention, the end of the first shaft is
Rotated by external power in a cylindrical cage provided in the section
Insert the end of the driven second shaft, and insert the first shaft and its
There is a clearance in the direction of rotation between the outer ring and the cage of the first shaft.
A torque transmission mechanism is installed to neutralize this torque transmission mechanism.
Hold it in the position and the rotation torque exceeding the set torque is transmitted.
Elastically deforms until the above clearance in the rotation direction disappears.
A torque setting elastic member is installed between the first shaft and the outer ring.
In the pocket formed in the cage, the first shaft
When the outer ring and the outer ring rotate relative to each other by a predetermined angle, the outer circumference of the second shaft
In the same direction as the first shaft of the second shaft by engaging the surface and the inner peripheral surface of the outer ring
The engaging member that transmits only the rotation of the
The joint member is such that the torque transmission mechanism is neutral in the rotational direction clearance.
The outer peripheral surface of the outer ring and the outer surface of the second shaft when held in place.
The torque transmission mechanism is engaged in the rotation direction without engaging with the peripheral surface
Before engaging with the outer ring and the second shaft.
Is adopted.

[0009]

In the first aspect of the invention, when the rotational torque applied to the first shaft is less than or equal to the set torque of the torque setting elastic member, the elastic deformation amount of the torque setting elastic member is small and the engaging member is the second shaft. In a state where it does not engage with the outer peripheral surface and the inner peripheral surface of the outer ring, the clutch does not operate, and the rotational force is transmitted from the first shaft to the second shaft.

When the rotation torque of the first shaft exceeds the set torque of the torque setting elastic member, the torque setting elastic member is largely elastically deformed, and the first shaft relatively rotates relatively to the second shaft. Thus, the engagement member engages the outer peripheral surface of the second shaft and the outer peripheral surface of the outer ring to engage the clutch, and two rotations of the first shaft and the outer ring are transmitted to the second shaft.

When the clutch device thus constructed is used in an electric power steering device, the first shaft is connected to the handle shaft, the second shaft is connected to the pinion shaft, and the rotation of the motor is transmitted to the outer wheel. To do so. This allows
When the handle operating force is less than or equal to the set torque of the torque setting elastic member, the manual operating force is transmitted from the handle shaft to the pinion shaft. When the set torque is exceeded, the clutch operates and the torque of the motor is transmitted to the pinion shaft. Therefore, the wheels can be operated with a very small steering wheel operating force.

If an abnormality occurs in the drive system including the motor and it does not operate, if the handle operating force is equal to or greater than the torque set by the torque setting elastic member, the relative rotation of the first shaft and the second shaft causes engagement. The coupling member tries to engage the outer peripheral surface of the second shaft and the outer peripheral surface of the outer ring, but with respect to the rotational movement from the first shaft, the engaging member slides on the inner peripheral surface of the outer ring and is disconnected from the drive system. In this state, the steering wheel operating force is transmitted to the pinion shaft, enabling manual steering.

Further, when the steering wheel is returned from the wheel side at the time of recovering from a curve, the driver applies only a torque that allows the steering wheel to be slipped lightly by hand, so the torque is less than the set torque, and the drive system does not operate the clutch. Instead, it goes into the state of manual operation.

Therefore, by properly setting the spring force of the torque setting elastic member, manual operation is performed below the set torque, power steering is automatically switched over when the set torque is exceeded, and a drive system including a motor or the like is used. Even when an abnormality occurs, the manual steering wheel operation force does not become excessive, and the steering wheel can be smoothly returned without causing the driver to feel discomfort when recovering from a curve.

In the second invention, when the rotational torque of the first shaft exceeds the set torque of the torque setting elastic member, the engaging member engages with the outer peripheral surface of the second shaft and the inner peripheral surface of the outer ring, The rotations of the first shaft and the second shaft can be transmitted to the outer ring. When the clutch device according to the second invention is incorporated in the electric power steering device, the first shaft is connected to the handle shaft, the outer ring is connected to the pinion shaft, and the rotation of the motor is transmitted to the second shaft. .

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

1 to 4 show a first embodiment of a clutch device according to the present invention. As shown in the figure, the first shaft 11 has a cylindrical retainer 12 at the end thereof, and the angular shaft portion 14 formed at the end of the second shaft 13 is inserted into the retainer 12.

A small-diameter shaft portion 15 is provided on the end surface of the angular shaft portion 14, and the small-diameter shaft portion 15 is inserted into a shaft insertion hole 16 formed at the closed end of the cage 12 and is rotatable via a bearing 17. Supported by.

A pin 18 facing the outer diameter is provided on the outer periphery of the square shaft portion 14, and the pin 18 is the retainer 1 of the first shaft 11.
It is inserted in the pin hole 19 formed in 2. Pin hole 19
Is a long hole extending in the circumferential direction of the cage 12, and a rotational clearance A is provided between the pin 18 and both ends of the hole (see FIG. 3). In addition, the pin hole 19 has a torque setting elasticity composed of springs on both sides of the pin 18.
The member 20 is incorporated, and the torque setting elastic member 20 holds the pin 18 in the neutral position of the clearance A in the rotational direction.

Here, the spring force of the torque setting elastic member 20 is such that when a predetermined or more rotational force acts on the first shaft 11,
The torque setting elastic member 2 until the clearance A in the rotation direction disappears
0 is elastically deformed, and the cage 12 and the second shaft 13 are pin 18
To be engaged via.

A cylindrical outer ring 21 is provided on the outer side of the connecting portion between the first shaft 11 and the second shaft 13, and the outer ring 21 is provided with two bearings 22, 22 for the first shaft 11 and the second shaft. It is supported so as to be relatively rotatable with respect to both shafts of 13.

The retainer 12 of the first shaft 11 is provided with a plurality of pockets 23 at predetermined intervals in the circumferential direction. Each pocket 23 has a flat surface 14a on the outer periphery of the angular shaft portion 14.
And two engaging members 24a, 24b formed of rollers in the pocket 23, and the engaging members 24a, 24
Wall surfaces 2 facing each other in the circumferential direction of the pocket 23
An elastic body 25 that is pressed against 3a is incorporated. Each of the engaging members 24a and 24b engages with both the flat surface 14a of the angular shaft portion 14 and the cylindrical inner surface 21a of the outer ring 21 when the pin 18 shown in FIG. Not not.

The clutch shown in the first embodiment has the above structure, and when this clutch device is used in an electric power steering device, as shown in FIG.
The handle shaft 41 with 0 is connected to the first shaft 11
A shaft 44 of a pinion 43 that meshes with the rack 42 is connected to the shaft 13. Further, a sensor 45 for detecting the twist of the handle shaft 41 is provided, and the rotation of the motor 47 controlled by the sensor 45 through the control device 46 is transmitted to the outer ring 21 via the torque transmission mechanism 48 of the gear electric mechanism. . Therefore, a torque transmitting member such as a gear is attached to the outer ring 21.

In the assembled state as described above, when the handle 40 is rotated and a rotational force in the direction indicated by the arrow in FIG. 3 is applied to the first shaft 11, the handle operating force sets the torque setting elastic member 20. If the torque is equal to or less than the torque, the deformation of the torque setting elastic member 20 is small, and the first shaft 11 does not rotate much with respect to the second shaft 13.
a and 24b do not engage with the flat surface 14a of the square shaft portion 14 of the second shaft 13 and the cylindrical inner surface 21a of the outer ring 21, and the clutch does not operate.

Therefore, when the steering wheel operating force is small, no rotational force is transmitted from the outer ring 21 to the second shaft 13, and the steering wheel is manually operated.

When the handle operating force increases and exceeds the set torque of the torque setting elastic member 20, the retainer 12 of the first shaft 11 moves to the torque setting elastic member 20 as shown in FIG.
Until the rotation direction clearance A disappears by elastically deforming the
Rotating relative to the shaft 13, the retainer 12 to the pin 18,
The operating force is transmitted to the wheels via the second shaft 13, the pinion shaft 44, the pinion 43, and the rack 42.

At the same time, the cage 12 is rotated relative to the second shaft 13 so that the right engaging member 24a of the pair of engaging members 24a, 24b housed in the pocket 23 is engaged.
Is engaged with the flat surface 14a of the angular shaft portion 14 and the cylindrical inner surface 21a of the outer ring 21 by the elastic force of the elastic body 25.

On the other hand, the operating force is transmitted to the wheels, and a torque is generated on the handle shaft 41 due to the resistance from the wheels. The torque is detected by the sensor 45 provided on the handle shaft 41, and the motor 47 is driven through the control device 46. Let The rotation of the motor 47 is transmitted to the outer ring. At this time,
Since the clutch is already in operation, the rotation of the motor 47 is transmitted from the outer ring 21 to the second shaft 13 via the engaging member 24a and to the wheels via the pinion shaft 44, the pinion 43 and the rack 42. .

As described above, when the steering wheel operating force exceeds the set torque, the steering mode is switched to the power steering, and the wheels can be steered with a very slight steering wheel operating force.

If an abnormality occurs in the drive system including the control device 46 and the motor 47 and they do not operate, the handle 40 is operated to rotate the first shaft 11 connected to the handle shaft 41. . When the first shaft 11 is rotated relative to the second shaft 13 in the left direction, for example, the engaging member 24a is pushed in the circumferential direction to be in the state shown in FIG.
The clutch does not operate depending on the rotation from the engaging member 2
4a slides on the cylindrical inner surface 21a of the outer ring 21 and moves in the circumferential direction.

Therefore, from the first shaft 11 to the pin 18, the second shaft 13, the pinion shaft 44, the pinion 43, and the rack 42.
The manual operation force is transmitted to the wheels via the control unit, and is not isolated from the driving system, so that the manual operation force of the steering wheel does not become excessive.

Further, the operation when the steering wheel is returned from the wheel side when the drive system does not operate will be described. At the time of recovery from the curve, the force is transmitted from the wheels to the rack 42, the pinion 43, the pinion shaft 44, and the second shaft 13. With respect to this steering wheel returning force, the driver applies only a certain amount of torque without slipping the steering wheel with his or her hand, and therefore is less than or equal to the set torque of the torque setting elastic member 20. in this case,
Since the first shaft 11 does not rotate relatively relative to the second shaft 13, the engagement member 2 housed in the pocket 23 of the retainer 12
4a is a cylindrical inner surface 21a of the outer ring 21 and the angular shaft portion 14
Does not engage the flat surface of the. Therefore, the clutch does not operate, and the first shaft 11 and the handle 40 connected to the first shaft 11 are returned with the outer shaft 21 (non-rotatable) disconnected from the second shaft 13.

Therefore, at the time of recovering from the curve, the steering wheel can be smoothly returned without giving the driver a feeling of strangeness.

6 and 7 show a second embodiment of the clutch device according to the present invention. In the second embodiment, an axial hole 26 is formed in each of the first shaft 11 and the second shaft 13, and a torque setting elastic member 27 formed of a torsion bar is inserted into the hole 26, and the torque setting elasticity is set. The member 27 is fixed to the shafts 11 and 13 via a holder 28.

A rotation direction clearance A is provided between the pin 18 and the pin hole 19. Other configurations and operations are the same as those in the first embodiment, and the description thereof will be omitted.

FIG. 8 shows a third embodiment of the clutch device according to the present invention. In this embodiment, the torque setting member 27 including the torsion bar in the second embodiment is used.
Instead of this, a torque setting member 29 composed of a leaf spring is used.

FIG. 9 shows a fourth embodiment of the clutch device according to the present invention. In this embodiment, a concave cam surface 21b is provided on the inner diameter surface of the outer ring 21, and the outer diameter surface of the second shaft 14 is a cylindrical surface 14b.

Further, a pin 30 is provided on the inner diameter surface of the outer ring 21, and the pin 30 is inserted into the pin hole 19 formed in the cage 12 so that a clearance A in the rotational direction is provided between both ends of the pin hole 19 and the pin 30. Is forming.

Further, a torque setting elastic member 20 made of a spring is incorporated between the pin 30 and the pin hole 19 to form the pin 30.
Is held at the neutral position of the clearance A in the rotation direction.

When the clutch device is used in the electric power steering device of FIG. 5, the outer wheel 21 is connected to the pinion shaft 44 so that the rotational force of the motor is transmitted to the second shaft 14.

In the embodiment, the pair of engaging members 24
Although a coil spring is used as the elastic body 25 that presses a and 24b in opposite directions, a leaf spring may be used as shown in FIGS. In this leaf spring, inclined piece portions b are provided at both ends of a first pressing piece portion a that presses one of the pair of engaging members 24a and 24b, and both end portions of the inclined piece portion b are provided. A second pressing piece portion c for pressing the other engaging member 24b is formed on the.

As shown in FIGS. 12 and 13, a bent piece d that engages with both end surfaces of the other engaging member 24b is provided at the end of the second pressing piece c, and the first pressing piece a is provided. , The inclined piece b and the second pressing piece c, respectively, the engaging members 24a, 24
If a leaf spring having a slit e formed by fitting a part of b is used, the cage 12 and the second shaft 13 or the outer ring 21 can be relatively rotated, so that the leaf spring shown in FIG. 10 is used. The operating angle of the clutch can be made larger than that of the above-mentioned clutch.

When the operating angles are the same, the outer diameters of the engaging members 24a and 24b can be increased, and the capacity of the clutch can be increased.

[0044]

Since the present invention has the above-mentioned structure, the following effects can be obtained.

(B) The torque is transmitted from the first shaft to the second shaft when the torque is less than the set torque, and the first torque is transmitted when the torque is more than the set torque.
This enables a clutch device that mechanically switches the two inputs of the shaft and the outer ring without external control, and transmits the power to the second shaft.

(B) Since the first shaft is connected to the second shaft by a mechanical engagement structure, the reliability of transmission is high.

(C) The structure is simple and compact.

(D) When the present clutch device is used in an electric power steering device, it has a simple structure due to the set spring force of the torque setting elastic member, and when the handle operating force is less than the set torque, it is manually operated. When the set torque is exceeded, the power steering can be automatically switched, and when an abnormality occurs in the drive system that drives the outer wheels, the steering wheel operating force is transferred to the pinion shaft in the state of disconnecting from the drive system. Since it can be transmitted, steering cannot be disabled, and the safety and reliability of the electric power steering device can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a clutch device according to the present invention.

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

FIG. 3 is an enlarged sectional view of the above.

FIG. 4 is a sectional view showing an operation state of the above.

FIG. 5 is a schematic view of a state in which the clutch device of the present invention is used in an electric power steering device.

FIG. 6 is a vertical sectional view showing a second embodiment of the clutch device according to the present invention.

FIG. 7 is a sectional view taken along the line VII-VII of FIG. 6;

FIG. 8 is a longitudinal sectional view showing a third embodiment of the clutch device according to the present invention.

FIG. 9 is a sectional view showing a fourth embodiment of the clutch device according to the present invention.

FIG. 10 is a plan view showing another example of the elastic body that presses the engaging member.

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

FIG. 12 is a plan view showing still another example of the elastic body.

FIG. 13 is a sectional view taken along lines XIII-XIII in FIG. 12;

FIG. 14 is a schematic diagram showing a conventional electric power steering device.

[Explanation of symbols]

11 1st shaft 12 Cage 13 2nd shaft 20, 27 , 29 Torque setting elastic member 21 Outer ring 24a, 24b Engaging member

Claims (2)

(57) [Claims] 1. An end of a second shaft provided coaxially with the first shaft is inserted into a cylindrical retainer provided at the end of the first shaft, and the first shaft and the second shaft are inserted. A torque transmission mechanism with a rotation direction clearance is provided between the two, and this torque transmission mechanism is held in the neutral position, and when a rotational force exceeding the set torque is transmitted, it elastically deforms until the above rotation direction clearance disappears. A member is provided between the first shaft and the second shaft, an outer ring that is rotationally driven by external power is provided outside the cage, and the first shaft and the first shaft are provided in a pocket formed in the cage. Engagement that engages the inner peripheral surface of the outer ring and the outer peripheral surface of the second shaft when the two shafts rotate relative to each other by a predetermined angle, and transmits only the rotation of the outer ring in the same direction as the first shaft to the second shaft. The member is housed, and the engaging member holds the torque transmission mechanism in the neutral position of the clearance in the rotational direction. In this state, the inner peripheral surface of the outer ring and the outer peripheral surface of the second shaft are not engaged, but the outer ring and the second shaft are engaged before the torque transmission mechanism is engaged in the rotational direction. Characteristic clutch. 2. An end portion of a second shaft, which is rotationally driven by external power, is inserted into a cylindrical retainer provided at the end portion of the first shaft, and the first shaft and the first shaft are A torque transmission mechanism with a rotational clearance is provided between the cage and the outer ring.
A torque setting elastic member is provided between the first shaft and the outer ring, which holds the torque transmission mechanism in a neutral position and elastically deforms until the clearance in the rotation direction disappears when the rotation torque exceeding the set torque is transmitted. In the pocket formed in the cage, when the first shaft and the outer ring relatively rotate by a predetermined angle, engage with the outer peripheral surface of the second shaft and the inner peripheral surface of the outer ring,
An engaging member that transmits only the rotation of the second shaft in the same direction as the first shaft to the outer ring is housed, and the engaging member holds the torque transmitting mechanism in the neutral position of the rotation direction clearance while the outer ring is being held. Is not engaged with the inner peripheral surface of the second shaft and the outer peripheral surface of the second shaft, but is engaged with the outer ring and the second shaft before the torque transmission mechanism is engaged in the rotational direction. clutch.