JP2013043521A - Torque transmission apparatus for steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish a torque transmission apparatus for a steering device, with which a steering device can be obtained in such a manner that, when an impactive torque is added to a constituent member, the fact thereof can be easily recognized by an operator.SOLUTION: In an engaging part between a female spline part 14 of a yoke 10 and a male spline part 16 of a shaft 11, there are provided: a part where a groove 19a and teeth 18a are engaged without backlash in a peripheral direction as shown by in (A) in an initial state; and a part where a groove 19 and teeth 18 are engaged via a gap in the peripheral direction. If an impactive torque is added between both the members 10, 11 because of a collision accident or the like, the groove 19a and the teeth 18a are disengaged as shown in the order of (A)→(B), a positional relation between both the members 10, 11 is deviated in a rotating direction, and a side surface of the groove 19 and a side surface of the teeth 18 are butted. In such a state, vibration or abnormal noise is generated with disengagement or butt in accordance with operation of a steering wheel, and thereby, it is recognized that the impactive torque has been added.

Description

  The present invention constitutes a steering device for imparting a steering angle to a steered wheel of a vehicle (automobile) (usually a front wheel, excluding special vehicles such as forklifts), and transmits the movement of the steering wheel to the steering gear unit. The present invention relates to an improvement of a torque transmission device. Specifically, when an impact is applied from the side of the steering gear unit due to a collision accident or an error in driving operation, resulting in damage to the components of the steering device. It enables the driver to understand the fact that such an impact has been applied while enabling the driving operation.

  As a steering device, for example, a structure as shown in FIG. 9 is widely known. In this steering apparatus, a steering shaft 3 is rotatably supported on the inner diameter side of a cylindrical steering column 2 supported by a vehicle body 1. A steering wheel 4 is fixed to the rear end portion of the steering shaft 3 protruding rearward from the rear end opening of the steering column 2. When the steering wheel 4 is rotated, this rotation is transmitted to the input shaft 8 of the steering gear unit 7 via the steering shaft 3, the universal joint 5a, the intermediate shaft 6, and another universal joint 5b. When the input shaft 8 rotates, a pair of tie rods 9, 9 arranged on both sides of the steering gear unit 7 are pushed and pulled, and a steering wheel according to the operation amount of the steering wheel 4 is turned to a pair of left and right steering wheels. A corner is given.

  In the steering apparatus as described above, there are a plurality of connecting portions between the steering wheel 4 and the input shaft 8, each of which transmits a steering torque. For example, the base end portion of the yoke constituting the universal joints 5a and 5b and the end portion of the shaft coupled by the universal joints 5a and 5b (the front end portion of the steering shaft 3 and the both end portions of the intermediate shaft 6) The connecting portion with the base end portion of the input shaft 8 also corresponds to the connecting portion as described above. Conventionally, with regard to the joint between the shaft and the yoke of the universal joint, the front end of the shaft and the base end of the yoke are fitted by interference fitting, serration fitting, welding, caulking, or a combination thereof. Etc. (see, for example, Patent Documents 1 and 2), in a state in which the relative displacement in the rotational direction is completely prevented, the torque is transmitted.

  When a vehicle equipped with a steering device as described above causes a collision accident or when a steering wheel is climbed on a curb due to an error in driving operation, the steering gear unit 7 side is shocked by the components of the steering device. Torque may be applied. And based on such a shocking torque, all or a part of the constituent members may be damaged, which may hinder continuous safe operation. In such a case, the user may bring the vehicle into a repair shop and immediately receive inspection and repair. However, some users can continue to use the vehicle without feeling any abnormality. There is sex.

JP 2000-291679 A JP 2007-40420 A

  In view of the circumstances as described above, the present invention provides a torque transmission device for a steering device that can obtain a steering device that allows a driver to easily and reliably recognize the applied fact when a shocking torque is applied to a component. Invented to realize the above.

  The torque transmission device for a steering device according to the present invention includes first and second torque transmission members that are concentrically arranged and connected in series with respect to a torque transmission direction. And it is provided in the middle of the torque transmission mechanism which transmits the motion of a steering wheel to the input shaft of a steering gear unit, and is used for the torque transmission between the said steering wheel and this input shaft.

  In particular, in the torque transmission device for a steering device according to the present invention, the coupling hole formed in a part of the first torque transmission member and the coupling hole formed in a part of the second torque transmission member. A coupling flange inserted inside the hole. Of these, on the inner peripheral surface of the coupling hole, either one of the engaging convex portion and the engaging concave portion and the hole-side abutting surface portion are provided at different positions in the circumferential direction. Further, on the outer peripheral surface of the coupling flange portion, the other part of the engaging convex portion and the engaging concave portion and the shaft side abutting surface portion are provided at different positions in the circumferential direction. Further, the engaging convex portion is engaged with the engaging concave portion without causing a backlash in the circumferential direction, and a threshold value is set between the first and second torque transmitting members. Only when a torque exceeding the magnitude is applied, based on the fact that at least one of the first and second torque transmitting members is elastically deformed, the peripheral surface provided with the engaging recess is this By getting on the part that is disengaged in the circumferential direction from the engagement recess, the engagement with the engagement recess is released. The threshold is set to a magnitude equal to or greater than the normal maximum transmission torque transmitted from the steering wheel to the input shaft when the steering wheel is operated with the vehicle stopped. Further, the hole side and shaft side abutting surface portions are arranged at positions separated from each other in the circumferential direction in an initial state in which the engagement convex portion and the engagement concave portion are engaged, and When the engagement between the engagement convex portion and the engagement concave portion is released, and the positional relationship between the first and second torque transmission members deviates by a predetermined amount from the initial state to each side in the rotational direction. Only collide with each other.

  When implementing the present invention as described above, for example, as in the invention described in claim 2, a female spline portion is formed on the inner peripheral surface of the coupling hole, and the female spline portion is disposed on the outer peripheral surface of the coupling flange portion. Engaging male spline portions are provided respectively. At the same time, a part of the plurality of teeth constituting either one of the female and male spline portions is defined as the engaging convex portion. Further, a part of the plurality of grooves provided between the plurality of teeth constituting the other spline portion of the female and male spline portions is defined as the engagement recess. Moreover, at least of each side surface existing in a part of the circumferentially opposite side surfaces of the plurality of teeth constituting the female spline portion that is disengaged from the engaging portion between the engaging convex portion and the engaging concave portion. A part of the side surfaces is a hole-side abutting surface portion. Moreover, at least of each side surface that exists in a part of the circumferentially opposite side surfaces of the plurality of teeth constituting the male spline portion that is disengaged from the engaging portion between the engaging convex portion and the engaging concave portion. A part of the side surfaces is referred to as a shaft side abutting surface portion.

When carrying out the invention described in claim 2, it is preferable that, as in the invention described in claim 3, each of the plurality of teeth constituting the one spline part is the engagement protrusion. The tooth height of each tooth to be a part is made smaller than the tooth height of each remaining tooth. At the same time, the heights of the plurality of teeth constituting the other spline portion are all made equal.
Alternatively, as in the invention described in claim 4, all the tooth heights of the plurality of teeth constituting the one spline portion are made equal. At the same time, among the teeth constituting the other spline portion, the tooth height of each tooth existing on both sides in the circumferential direction of the engaging recess is made smaller than the tooth height of the remaining teeth.
By adopting the configuration of the invention described in claim 3 or claim 4, when the torque exceeding the threshold is applied, the engagement between the engagement protrusions and the engagement recesses To be easily released.

Moreover, when implementing this invention, Preferably, the said coupling collar part is comprised like a cylinder like the invention described in Claim 5.
Further, by adopting such a configuration, when the torque exceeding the threshold is applied, the coupling flanges are easily elastically deformed, so that each of the engagement protrusions and each of the engagement recesses is provided. To be easily released.

In carrying out the present invention, it is preferable that, as in the invention described in claim 6, the coupling flange portion is pulled out from the coupling hole between the first and second torque transmitting members. A retaining structure is provided to prevent this.
When the present invention is carried out, the first and second torque transmitting members can be welded together as in the seventh aspect of the invention.
In this case, preferably, as in the invention described in claim 8, the strength of the welded portion where the first and second torque transmission members are welded to each other is not damaged by the normal maximum transmission torque, It is set as the magnitude | size damaged by the impact torque of the magnitude | size exceeding the said threshold value added between said 1st, 2nd torque transmission members from the said steering gear unit side.

  Further, as a specific form in carrying out the present invention, for example, as in the invention described in claim 9, one torque transmission member of the first torque transmission member and the second torque transmission member is provided. A universal joint yoke is used, and the coupling hole is formed at the base end of the yoke. Similarly, the other member is a shaft, and the coupling flange is provided at the end of the shaft.

According to the torque transmission device for a steering device of the present invention configured as described above, a vehicle equipped with the torque transmission device for a steering device may cause a collision accident, or the steering wheel may ride on a curb due to an error in driving operation. By doing so, when a shocking torque having a magnitude exceeding a threshold value is applied to the components of the steering device, the driver can easily recognize the applied fact.
That is, when the shocking torque is applied, the engagement between the engaging convex portion and the engaging concave portion is released, and the positional relationship between the first and second torque transmitting members is determined in the rotational direction from the initial state. By shifting the fixed amount, both the hole side and shaft side abutting surfaces abut each other. Further, when a steering torque in the direction opposite to the shocking torque is applied thereafter, the positional relationship between the first and second torque transmitting members with respect to the rotational direction is eliminated, and this positional relationship becomes the initial value. By returning to the state, the engaging convex portion and the engaging concave portion are engaged again. As described above, disengagement between the engaging convex portion and the engaging concave portion, the abutting between the hole side and shaft side abutting surface portions, and further re-engagement between the engaging convex portion and the engaging concave portion. When this occurs, vibrations and abnormal sounds (engagement release sound, collision sound, engagement sound) are generated. Among these, the vibration is transmitted to the steering hole, and the abnormal noise reverberates in the passenger compartment. Such vibrations and abnormal sounds can be easily sensed by the driver's five senses (tactile sense, hearing), so the driver can understand the fact that the shocking torque is applied based on the sense of these vibrations and abnormal sounds. Can be easily recognized. For this reason, the driver can be urged to repair, and the danger associated with continuing operation of the damaged vehicle can be avoided.

Sectional drawing of the coupling | bond part of a shaft and a yoke which shows the 1st example of embodiment of this invention. The a section enlarged view of FIG. The expanded bb sectional drawing of FIG. The enlarged view which shows the c section of FIG. 3 with the state (A) before applying an impact torque, and the state (B) after applying. The figure similar to FIG. 4 which shows the 2nd example of embodiment of this invention. The figure similar to FIG. 2 which shows the 3rd example of embodiment of this invention. The figure similar to FIG. 2 which shows the 4th example. The figure similar to FIG. 1 which shows the same 5th example. The partially cut side view which shows an example of the steering apparatus known conventionally.

[First example of embodiment]
1-4 show a first example of an embodiment of the present invention corresponding to claims 1, 2, 3, 5, 6, and 9. This example is an example in which the structure of the present invention is applied to the coupling portion between the yoke 10 and the shaft 11 (steering shaft or intermediate shaft) constituting the universal joint. Since the structure and operation of the universal joint including the yoke 10 are well known in the art, the illustration and description will be omitted or simplified, and the following description will focus on the features of this example.

  A coupling hole 13 is formed in the axial direction at the radial center of the base 12 of the yoke 10 which is the first torque transmission member. A female spline portion 14 is provided on the inner peripheral surface of the coupling hole 13. The female spline portion 14 is formed by arranging a plurality of teeth 15, 15 that are each long in the axial direction at an equal pitch in the circumferential direction. The tooth thickness (circumferential width) and the tooth height (radial height) of these teeth 15 are all equal. On the other hand, a coupling flange 16 having an outer diameter smaller than that of the proximal end portion is formed at the distal end of the shaft 11, which is the second torque transmission member. A male spline portion 17 is provided on the outer peripheral surface of the coupling flange portion 16. The male spline portion 17 is formed by arranging the same number of teeth 18, 18a as the teeth 15, 15 in the axial direction at equal pitches in the circumferential direction. And among these teeth 18 and 18a, the tooth thickness of some teeth 18a and 18a arranged every two in the circumferential direction is made thicker (larger) than the tooth thickness of the remaining teeth 18 and 18 Yes. At the same time, the tooth heights of the partial teeth 18a and 18a are made lower (smaller) than the tooth heights of the remaining teeth 18 and 18.

  The female spline portion 14 and the male spline portion 17 are engaged with each other by inserting the coupling flange portion 16 inside the coupling hole 13. In this state, in the case of this example, some of the teeth 18a, 18a constituting the male spline portion 17 are present between the plurality of teeth 15, 15 constituting the female spline portion 14. As shown in detail in FIG. 4A, with respect to some of the plurality of grooves 19, 19a, as shown in detail in FIG. 4A, there is no rattling in the circumferential direction (with a light interference fit). Engaged. On the other hand, the remaining teeth 18 and 18 constituting the male spline portion 17 are shown in detail in FIG. 4A with respect to the remaining grooves 19 and 19 constituting the female spline portion 14, respectively. In addition, they are engaged with each other with a predetermined amount of gap interposed on both sides in the circumferential direction. In the case of this example, some of the teeth 18a, 18a constituting the male spline portion 17 correspond to the engaging convex portions described in the claims. Of the plurality of grooves 19 and 19a constituting the female spline portion 14, some of the grooves 19a and 19a engaged with some teeth 18a and 18a constituting the male spline portion 17 are claimed. It corresponds to the engaging recess described in the range. Moreover, the circumferential direction both sides | surfaces of the remaining teeth 18 and 18 which comprise the said male spline part 17 are equivalent to the shaft side abutting surface part described in the claim, respectively. Further, of the circumferential side surfaces of the teeth 15 and 15 constituting the female spline portion 14, the side surfaces facing the circumferential side surfaces of the remaining teeth 18 and 18 constituting the male spline portion 17 are respectively claimed. It corresponds to the hole-side abutting surface portion described in the range.

  Further, in the case of this example, in the state where the coupling flange portion 16 is inserted inside the coupling hole 13 as described above, the distal end portion of the male spline portion 17 protruding from the coupling hole 13 is radially outward. The caulking portion 20 that protrudes into the center is formed by press caulking. Then, based on the engagement between the caulking portion 20 and the step portion 21 existing in the peripheral portion of the opening portion on the distal end side of the coupling hole 13, the coupling flange portion 16 moves from the coupling hole 13 to the proximal side. It prevents it from coming out. In the case of this example, the caulking portion 20 and the step portion 21 correspond to the retaining structure portion described in the claims.

  In the case of this example, when a torque exceeding a threshold is applied between the yoke 10 and the shaft 11, the base 12 and the coupling flange 16 are elastically deformed. As shown in FIG. 4 (B), some of the teeth 18a, 18a constituting the male spline part 17 ride on the teeth 15, 15 constituting the female spline part 14, The engagement of the partial teeth 18a and 18a with respect to the partial grooves 19a and 19a is released. In the case of this example, the threshold value is an operation of the steering wheel 4 (see FIG. 9) performed when the vehicle is stopped. The value is a little larger than the normal maximum transmission torque transmitted to (see FIG. 9). When a torque having a magnitude exceeding the threshold value is applied, as described above, the engagement of the partial teeth 18a and 18a with the partial grooves 19a and 19a is accurately released. Therefore, the shapes and dimensions of the teeth 15 and 18a and various factors related to the elasticity of the base 12 and the coupling flange 16 are restricted. For example, with respect to the shape and dimensions of the teeth 15 and 18a, the angle of inclination of both side surfaces in the circumferential direction of the teeth 15 and 18a and the height of the teeth of the teeth 18a and 18a are regulated. Yes. In addition, regarding various factors associated with the elasticity of the base 12 and the coupling flange 16, the base 12 and the coupling flange 16 are made of materials, dimensions such as radial thickness, processing methods such as cutting and forging, and heat treatment methods. Etc. are regulated respectively.

  As described above, in the case of the torque transmission device for a steering device according to the present embodiment, in the initial state, as shown in FIGS. 3 and 4A, in some of the grooves 19a and 19a constituting the female spline portion 14, On the other hand, some of the teeth 18a, 18a constituting the male spline portion 17 are engaged without causing any backlash in the circumferential direction. On the other hand, when a shocking torque having a magnitude exceeding the threshold is applied to the joint between the yoke 10 and the shaft 11 due to a collision accident or the curbing of the steering wheel, for example, FIG. ) → (B), the engagement of the partial teeth 18a with the partial grooves 19a is released. Accordingly, the positional relationship between the yoke 10 and the shaft 11 is deviated from the initial state by a predetermined amount in the rotational direction, so that the remaining front teeth 18 constituting the male spline portion 17 in the rotational direction front side surface ( The right side surface in FIG. 4 abuts on the circumferential side surface of the tooth 15 constituting the female spline portion 14. Further, when a steering torque in the direction opposite to the shocking torque is applied to the joint between the yoke 10 and the shaft 11, the rotational direction is as shown in the order of (B) → (A) in FIG. When the positional relationship between the yoke 10 and the shaft 11 is eliminated and the positional relationship returns to the initial state, the partial grooves 19a and the partial teeth 18a are engaged again. To do. As described above, the disengagement between the partial grooves 19a and 19a and the partial teeth 18a and 18a, the abutment between the side surfaces of the teeth 15 and 18, and further the partial grooves When re-engagement between the teeth 19a and 19a and the partial teeth 18a and 18a occurs, vibrations and abnormal sounds (engagement release sound, collision sound, engagement sound) are generated. Among these, the vibration is transmitted to the steering hole 4, and the abnormal noise reverberates in the passenger compartment. Such vibrations and abnormal sounds can be easily sensed by the driver's five senses (tactile sense, hearing), so the driver can understand the fact that the shocking torque is applied based on the sense of these vibrations and abnormal sounds. Can be easily recognized. For this reason, the driver can be urged to repair, and the danger associated with continuing operation of the damaged vehicle can be avoided.

[Second Example of Embodiment]
FIG. 5 shows a second example of an embodiment of the present invention corresponding to claims 1, 2, 4, 5, 6, and 9. In the case of this example, the structure of the female spline portion 14a provided on the inner peripheral surface of the coupling hole 13a of the yoke 10a and the male spline portion 17a provided on the outer peripheral surface of the coupling flange portion 16a of the shaft 11a has been described above. Slightly different from the first example. In the case of this example, regarding the male spline portion 17a, the height and thickness of all the teeth 18, 18b including the teeth 18b corresponding to the engaging convex portions are made equal to each other. Instead, with respect to the female spline portion 14a, the teeth 15a, 15a existing on both sides in the circumferential direction of the groove 19b corresponding to the engaging recess are made lower than the teeth of the remaining teeth 15, 15. ing. Further, by making the circumferential width of the groove 19b corresponding to the engaging recess smaller than the circumferential width of the other grooves 19 and 19, the teeth 18b corresponding to the engaging protrusion with respect to the groove 19b. Are engaged (with a light interference fit) without causing backlash in the circumferential direction.

  In any case, in the case of this example, as described above, the tooth heights of the teeth 15a and 15a existing on both sides in the circumferential direction of the groove 19b corresponding to the engaging recess are set to the teeth of the remaining teeth 15 and 15, respectively. When a torque exceeding a threshold value is applied to the joint between the yoke 10a and the shaft 11a by making it lower than the length, for example, as shown in the order of (A) → (B) in FIG. The teeth 18b corresponding to the engaging convex portions are easily climbed on the teeth 15a adjacent to the grooves 19b corresponding to the engaging concave portions. Since other configurations and operations are the same as those in the case of the first example described above, overlapping illustrations and descriptions are omitted.

  In the first and second examples described above, a structure in which the engaging convex portion is provided on the male spline portion side and the engaging concave portion is provided on the female spline portion side is employed. However, when carrying out the present invention, it is possible to adopt a structure in which the engaging convex portion is provided on the female spline portion side and the engaging concave portion is provided on the male spline portion side. In the case of implementing the present invention, when adopting a structure in which a female spline portion is provided on the inner peripheral surface of the coupling hole and a male spline portion is provided on the outer peripheral surface of the coupling flange portion, The number of combinations with the grooves serving as the engagement recesses and the manner of arrangement in the circumferential direction can be selected as appropriate. However, the number of combinations is preferably 3 or more, and the arrangement in the circumferential direction may be arranged at equal intervals in the circumferential direction or may be arranged at unequal intervals.

[Third example of embodiment]
FIG. 6 shows a third example of the embodiment of the invention corresponding to claims 1, 2, 3, 5, 6, and 9. In the case of this example, the shaft 11b has a circular tube shape. At the same time, by bending the distal end portion of the coupling flange portion 16b provided at the distal end portion of the shaft 11b to the outer diameter side by rolling caulking, the bent portion is used as a caulking portion 20a for preventing the removal. Yes. Since the structure and operation of the other parts are the same as in the case of the first example shown in FIGS. 1 to 4 described above, the same parts are denoted by the same reference numerals, and overlapping illustrations and descriptions are omitted.
The structure provided with the caulking portion 20a as described above can also be applied to the structure of the second example shown in FIG.

[Fourth Example of Embodiment]
FIG. 7 shows a fourth example of the embodiment of the invention corresponding to claims 1, 2, 3, 5, 6, and 9. In the case of this example, prior to inserting the coupling flange portion 16c of the shaft 11c into the coupling hole 13 of the yoke 10, the large-diameter male spline portion 22 is formed at the tip of the outer peripheral surface of the coupling flange portion 16c. Is provided. The pitch circle diameter of the large-diameter male spline portion 22 is slightly larger than the pitch circle diameter of the male spline portion 17 provided at the intermediate portion or the base end portion of the outer peripheral surface of the coupling flange portion 16c. In the case of this example, when the coupling flange 16c is inserted inside the coupling hole 13, the large-diameter male spline portion 22 is moved to the inner side of the female spline portion 14 by applying a large press-fitting load to the shaft 11c. Then, the inside of the female spline portion 14 is further passed. As shown in the figure, the female spline part 14 and the male spline part 17 are engaged with each other, and the entire large-diameter male spline part 22 is disposed outside the female spline part 14. In the case of this example having such a configuration, when the coupling flange portion 16c tends to come out from the inside of the coupling hole 13, the base edge of the large-diameter male spline portion 22 and the female spline portion 14 The tip edge is mechanically engaged in the axial direction. This prevents the coupling flange 16c from coming out from the inside of the coupling hole 13. In the case of this example, the base end edge of the large-diameter male spline part 22 and the front end edge of the female spline part 14 correspond to a retaining structure part. Since the structure and operation of the other parts are the same as in the case of the first example shown in FIGS. 1 to 4 described above, the same parts are denoted by the same reference numerals, and overlapping illustrations and descriptions are omitted.
The structure provided with the large-diameter male spline portion 22 as described above can also be applied to the structure of the second example shown in FIG.

[Fifth Example of Embodiment]
FIG. 8 shows a fifth example of an embodiment of the present invention corresponding to claims 1 to 3 and 5 to 9. In the case of this example, the yoke 10 and the shaft 11 are welded in a state in which the weld metal 23 is stretched over the inner peripheral portion of the base end surface of the yoke 10 and the tip end portion of the outer peripheral surface of the shaft 11. However, it is different from the case of the first example shown in FIGS. The strength of the weld metal 23 is not damaged by the normal maximum transmission torque that acts at the time of the stationary operation, but by the impact torque that is greater than the above threshold and acts in association with the collision accident or the curb ride on the steering wheel. It is supposed to be damaged. In the case of this example having such a configuration, torque transmission between the yoke 10 and the shaft 11 is performed mainly via the weld metal 23 during normal operation including during stationary operation. . Since the structure and operation of the other parts are the same as in the case of the first example shown in FIGS. 1 to 4 described above, the same parts are denoted by the same reference numerals, and overlapping illustrations and descriptions are omitted.
The structure in which the yoke and the shaft are welded can also be applied to the structure of the second example shown in FIG.

When carrying out the present invention, the threshold value that determines the range of torque for releasing the engagement between the engagement convex portion and the engagement concave portion may be a magnitude that is equal to or greater than the normal maximum transmission torque, depending on design conditions, etc. Can be set freely. That is, in each of the above-described embodiments, the threshold value is set to a value slightly larger than the normal maximum transmission torque. However, this threshold value may be set to a value larger than the normal maximum transmission torque. it can. By setting in this way, for example, it is possible to prevent plastic deformation or dropout from occurring in the first region to the extent that the steering wheel hits the curbstone lightly.
When the present invention is carried out and the first and second torque transmitting members are welded to each other, the strength of the welded portion can be freely set depending on design conditions and the like. In other words, the strength of the welded portion can be set to such a level that it can be broken by an impact torque having a value slightly larger than the threshold value. It can also be a size that does not break.
Further, the present invention is not limited to the coupling portion between the shaft and the universal joint yoke, and any portion that constitutes a steering device and transmits torque applied to the steering wheel to the input shaft of the steering gear unit can be used. This part can also be implemented. For example, the inner shaft constituting the steering shaft or the intermediate shaft is divided into two in the axial direction, and the structure of the present invention can be applied to the connecting portion between the ends of the two divided shafts.

DESCRIPTION OF SYMBOLS 1 Car body 2 Steering column 3 Steering shaft 4 Steering wheel 5a, 5b Universal joint 6 Intermediate shaft 7 Steering gear unit 8 Input shaft 9 Tie rod 10, 10a Yoke 11, 11a, 11b, 11c Shaft 12 Base 13, 13a Coupling hole 14, 14a Female spline part 15, 15a Teeth 16, 16a, 16b, 16c Coupling flange part 17, 17a Male spline part 18, 18a, 18b Teeth 19, 19a, 19b Groove 20, 20a Caulking part 21 Step part 22 Large diameter male spline part 23 Welding metal

Claims (9)

  In the middle of the torque transmission mechanism that includes both first and second torque transmission members arranged concentrically and connected in series with each other in the torque transmission direction, and transmits the movement of the steering wheel to the input shaft of the steering gear unit In a torque transmission device for a steering device provided for torque transmission between the steering wheel and the input shaft, a coupling hole formed in a part of the first torque transmission member, A coupling flange formed on a part of the second torque transmission member and inserted inside the coupling hole, and an engagement convex portion and an engagement concave portion on the inner peripheral surface of the coupling hole. Any one of the two portions and the hole-side abutting surface portion are provided at different positions in the circumferential direction, and the engaging convex portion and the engaging concave portion are formed on the outer peripheral surface of the coupling flange portion. The other of The portion and the shaft-side abutting surface portion are provided at positions different from each other in the circumferential direction, and the engagement convex portion engages with the engagement concave portion without causing backlash in the circumferential direction. And only when a torque exceeding the threshold is applied between the first and second torque transmission members, at least one of the first and second torque transmission members. Is engaged with the engagement recesses by riding on a portion of the peripheral surface provided with the engagement recesses that is removed from the engagement recesses in the circumferential direction. And the threshold value is set to a magnitude equal to or greater than a normal maximum transmission torque transmitted from the steering wheel to the input shaft when the steering wheel is operated with the vehicle stopped. , Shaft side both sides Are disposed at positions spaced apart from each other in the circumferential direction in the initial state in which the engaging convex portion and the engaging concave portion are engaged, and the engaging convex portion and the engaging concave portion Only when the engagement between the first and second torque transmitting members is disengaged by a predetermined amount from the initial state to each side in the rotational direction. Torque transmission device for steering device.   A female spline portion is provided on the inner peripheral surface of the coupling hole, and a male spline portion that engages with the female spline portion is provided on the outer peripheral surface of the coupling flange portion, and any one of the female and male spline portions is provided. A part of the plurality of teeth constituting one spline portion is defined as the engaging convex portion, and the plurality of teeth constituting the other spline portion of the female and male spline portions are between each other. A part of the plurality of grooves provided in each of the plurality of grooves is defined as the engagement recess, and each of the engagement protrusions and each of the plurality of teeth on both sides in the circumferential direction constituting the female spline portion Both side surfaces in the circumferential direction of a plurality of teeth constituting the male spline portion, wherein at least some of the side surfaces existing in the portion removed from the engaging portion with the engaging concave portion are defined as hole side abutting surface portions, respectively. Among the above, each engaging projection and each engaging recess At least a portion of the side surface, and a shaft side abutment surface respectively, steering system torque transmitting device according to claim 1 of the respective side surfaces that are present on the edge portion from the engagement portion of the.   Among the plurality of teeth constituting the one spline part, the tooth height of each tooth that becomes the engagement convex part is made smaller than the tooth height of each remaining tooth, and the other spline part is constituted. The torque transmission device for a steering device according to claim 2, wherein the tooth heights of the plurality of teeth are all equal.   The tooth lengths of the plurality of teeth constituting the one spline part are all made equal, and among the teeth constituting the other spline part, each of the teeth existing on both sides in the circumferential direction of the engagement recess The torque transmission device for a steering device according to claim 2, wherein the tooth height is smaller than the tooth height of each remaining tooth.   The torque transmission device for a steering device according to any one of claims 1 to 4, wherein the coupling flange portion is configured in a cylindrical shape.   6. The retaining structure portion for preventing the coupling flange portion from coming out of the coupling hole is provided between the first and second torque transmission members. The torque transmission device for a steering device according to item 1.   The torque transmission device for a steering device according to any one of claims 1 to 6, wherein the first and second torque transmission members are welded to each other.   The strength of the welded portion where the first and second torque transmission members are welded is not damaged by the normal maximum transmission torque, and between the first and second torque transmission members from the steering gear unit side. The torque transmission device for a steering device according to claim 7, wherein the torque transmission device is damaged by an impact torque having a magnitude exceeding the threshold. One torque transmission member of the first torque transmission member and the second torque transmission member is a yoke of a universal joint, and the coupling hole is formed at a base end portion of the yoke, and the other The torque transmission device for a steering device according to any one of claims 1 to 8, wherein the member is a shaft, and the coupling flange portion is provided at an end portion of the shaft.

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