JP2013032795A - Torque transmission device for steering apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a structure for obtaining a steering apparatus by which a driver can easily recognize a fact that an impact load is applied, when the impact load in a rotating direction or an axial direction is applied to a component member due to a collision accident or the like.SOLUTION: A yoke 10 and a shaft 11 are serration-engaged. As a structure of the serration engagement portion, a structure is adopted by which rattling in the rotating direction is not produced in a state before the application of an impact load, but rattling in the rotating direction is produced after the application. Because a play amount of a steering wheel changes before and after the rattling is produced, the fact of application of an impact load can be recognized.

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, in the event of an impact that may cause damage to the components of the steering device due to a collision accident or the like, the driver can understand the fact that such an impact has been applied while enabling driving operation. It is to make.

  As a steering device, for example, a structure as shown in FIG. 24 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 the 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 portions of the yokes constituting the universal joints 5a and 5b and the distal end portions of the shafts connected 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), a structure is adopted that allows torque transmission in a state where there is no rattling in the rotational direction. Further, when adopting such a structure, generally, in order to prevent the shaft and the yoke from being relatively displaced in the axial direction, whether the strength of the welding and the caulking is sufficiently ensured, Or, even when the shaft and the yoke are relatively displaced in the axial direction, it is possible to adopt a structure that maintains a coupled state capable of transmitting torque without causing rattling in the rotational direction. It is customary.

  By the way, at the joint portion between the members that transmit torque as described above, the rotation direction and the axial direction of the vehicle are caused based on the fact that the vehicle causes a collision accident or the steering wheel is climbed on the curb due to an error in driving operation. Impact load may be applied. And based on such an impact load, all or a part (welding part, press fit part, etc.) of the above-mentioned joint part may be damaged, and it may interfere with 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 is a torque for a steering device that can obtain a steering device that allows a driver to easily recognize the fact that the component member has been subjected to an impact load in a rotational direction or an axial direction. The invention was invented to realize a transmission device.

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 of the present invention, the first and second torque transmission members are coupled so as to be able to transmit torque without causing backlash in the rotational direction, and Based on the relative displacement in the axial direction by a predetermined amount, the state is changed to a state where the torque can be transmitted through the backlash in the rotational direction.

When carrying out the present invention, as in the invention described in claim 2, for example, the first torque transmitting member is connected to a coupling hole and an outer diameter side engaging portion provided on the inner peripheral surface of the coupling hole. It shall have. Further, torque can be transmitted to the coupling flange portion in which the second torque transmission member is inserted inside the coupling hole and the outer diameter side engagement portion provided on the outer peripheral surface of the coupling flange portion. It has an inner diameter side engaging part engaged with.
In addition, the first and second torque transmission members are coupled in such a manner that torque can be transmitted without causing backlash in the rotational direction. The outer diameter side engaging portion and the inner diameter side engaging portion engage with each other so that torque can be transmitted without causing a backlash in the rotation direction. It will be in the state.
In addition, the first and second torque transmission members are coupled to each other so that torque can be transmitted with the rotation in the direction of rotation. With respect to each other, the outer diameter side engaging portion and the inner diameter side engaging portion have a backlash in the rotational direction. Is engaged so that torque can be transmitted.
Further, a retaining structure portion is provided between the first and second torque transmitting members to prevent the coupling flange from coming out of the coupling hole.

In this case, more specifically, as an engagement mode of the outer diameter side engagement portion and the inner diameter side engagement portion that enables transmission of torque, for example, the invention according to claim 3 Similarly, serration engagement is adopted, non-circular fitting is adopted as in the invention described in claim 4, or key engagement is adopted as in the invention described in claim 5. . Alternatively, as in the invention described in claim 6, friction engagement is adopted as a structure that enables transmission of torque without causing backlash in the rotational direction, and torque is applied with the backlash in the rotational direction interposed. As a structure that enables transmission of the above, any of serration engagement, non-circular fitting, and key engagement as described above can be adopted.
Further, in these cases, more specifically, as in the invention described in claim 7, for example, the retaining structure portion is formed by mechanically moving parts of the first and second torque transmitting members in the axial direction. Based on the fact that they are engaged with each other, it is possible to prevent the coupling flange from coming out of the coupling hole.

  Further, as a specific mode for carrying out the invention described in claims 2 to 7 as described above, for example, as in the invention described in claim 8, the first torque transmission member and the second torque transmission are used. One torque transmission member of the members is a universal joint yoke, and the coupling hole is formed at the base end of the yoke. Similarly, the other torque transmission member is a shaft, and the coupling flange is provided at the end of the shaft.

  Further, when the present invention is carried out, as in the invention described in claim 9, for example, the first and second torque transmitting members can transmit torque without causing backlash in the rotational direction. Can also be welded together. The strength of the welded portion can be set to an arbitrary size. That is, the strength of the welded portion may be set to a size at which the welded portion is damaged by a relatively small impact load, or may be set to a size at which the welded portion is damaged by a relatively large impact load.

In the case of the torque transmission device for a steering device according to the present invention configured as described above, both the first and the second are based on the fact that the vehicle causes a collision accident or the steering wheel rides on the curb due to an error in driving operation. When an impact load in the rotational direction or the axial direction is applied to the coupling portion between the torque transmitting members, the driver can easily recognize the applied fact.
That is, based on the impact load as described above being applied to the coupling portion, the position regulating force in the axial direction between the first and second torque transmitting members (for example, based on the tightening margin of the fitting portion or welding) When the position regulating force is reduced or lost, the first and second torque transmitting members are displaced relative to each other by a predetermined amount in the axial direction, for example, by repeatedly applying steering torque to the coupling portion during traveling. Along with this, the coupling state between the first and second torque transmission members is such that torque transmission can be performed without causing rotation in the rotational direction, and torque transmission is performed with the backlash in the rotational direction interposed. Changes to a possible state. As a result, the play of the steering wheel (the operation range that does not lead to a change in the steering angle of the steered wheel) is increased by the amount of the rattling, and in some cases, the vibration generated based on the rattling is the steering wheel. Or an abnormal noise generated based on this rattling is echoed in the passenger compartment. Since such a change in the situation can be easily felt by the driver, the driver can easily recognize the fact that the impact load as described above is applied based on the change in the situation. 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 which shows the 1st example of embodiment of this invention in the state before an impact load is added. FIG. 2 is a cross-sectional view taken along the line aa in FIG. 1. The b section enlarged view of FIG. Cc sectional drawing (A) and dd sectional drawing (B) of FIG. The figure similar to FIG. 3 shown in the state after an impact load is applied. FIG. 6 is an ee sectional view (A) and an ff sectional view (B) in FIG. 5. Sectional drawing which shows the 2nd example of embodiment of this invention in the state before an impact load is added. Gg sectional drawing (A) and hh sectional drawing (B) of FIG. The figure similar to FIG. 7 shown in the state after an impact load is applied. Ii sectional drawing (A) and jj sectional drawing (B) of FIG. The k arrow line view of FIG. The partial side view (A) of the shaft shown in the state before assembling the 3rd example of an embodiment of the invention, and the partial sectional view (B) of a yoke. Sectional drawing shown in the state before an impact load is added. FIG. 14 is a sectional view taken along the line m-m in FIG. The figure similar to FIG. 13 shown in the state after the impact load was added. OO sectional drawing (A) and pp sectional drawing (B) of FIG. The partial side view (A) of the shaft shown in the state before assembling the 4th example of an embodiment of the invention, and the partial sectional view (B) of a yoke. Sectional drawing shown in the state before applying an impact load after an assembly. The qq sectional view (A) and rr sectional view (B) in FIG. The figure similar to FIG. 18 shown in the state after an impact load is applied. Ss sectional drawing (A) and tt sectional drawing (B) of FIG. The fragmentary sectional view which shows the 5th example of embodiment of this invention in the state before an impact load is added. The fragmentary sectional view which shows the 6th example of embodiment of this invention in the state before an impact load is added. The partially cut side view which shows an example of the steering apparatus known conventionally.

[First example of embodiment]
FIGS. 1-6 has shown the 1st example of embodiment of this invention corresponding to Claims 1-3 and 7-9. 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. 1 to 4 show a normal state before the relative impact load in the rotational direction or the axial direction acts between the yoke 10 and the shaft 11, and FIGS. Each of the states at the time of abnormality, which is a state after the impact load is applied, is shown. 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 12 is formed in the axial direction in the central portion in the radial direction of the base portion of the yoke 10 which is the first torque transmission member. The inner peripheral surface of the coupling hole 12 is a female serration portion 13 that is an outer diameter side engaging portion. Further, the female serration portion 13 has an axially leading half (left half in FIGS. 1, 3 and 5) as a relatively small-diameter small-diameter female serration portion 14, and an axial base half (FIG. 1, FIG. The right half portion in 3 and 5 is a large-diameter female serration portion 15 having a relatively large diameter. On the other hand, at the distal end portion of the shaft 11 that is the second torque transmission member, a coupling flange portion 16 having an outer diameter smaller than that at the proximal end portion is provided. The outer peripheral surface of the coupling flange 16 is a male serration portion 17 which is an inner diameter side engagement portion capable of serration engagement with the female serration portion 13. The male serration portion 17 has an axially distal end portion (left end portion in FIGS. 1, 3 and 5) as a relatively small-diameter small-diameter male serration portion 18 and an axially intermediate portion to a proximal end portion (FIG. 1). The right end portion in 3, 5) is a large-diameter male serration portion 19 having a relatively large diameter. Of these, the large-diameter male serration portion 19 can be serrated and engaged with the small-diameter female serration portion 14 with a close fit and the large-diameter female serration portion 15 with a clearance fit. The small-diameter male serration portion 18 can be serrated to the small-diameter female serration portion 14 with a gap fit.

  In the case of this example, the normal state shown in FIGS. 1 to 4, that is, the coupling flange 16 is inserted inside the coupling hole 12, and the yoke 10 and the shaft 11 are connected to each other in the axial direction. In a state where the positional relationship is a regular positional relationship, the female serration portion 13 and the male serration portion 17 are engaged with each other so that torque can be transmitted in a state in which no rattling occurs in the rotational direction. . Specifically, as shown in detail in FIG. 3 and FIG. 4 (A), the small-diameter female serration portion 14 and the leading half of the large-diameter male serration portion 19 are serrated by interference fit. I am letting. In this state, as shown in detail in FIGS. 3 and 4B, the large-diameter female serration portion 15 and the base half of the large-diameter male serration portion 19 are serrated and engaged with a gap fit. ing.

  In the case of this example, in the normal state or at least the tip edge portion of the small-diameter male serration portion 18 protrudes from the coupling hole 12, the tip edge portion protrudes to the outer diameter side. The caulking portion 20 is formed by press caulking. When the coupling flange 16 is displaced from the coupling hole 12 in the direction of coming out to the base end side, the caulking portion 20 and the stepped portion 21 existing in the peripheral portion of the opening portion on the distal end side of the coupling hole 12; However, based on the mechanical engagement in the axial direction, the coupling flange 16 can be prevented from coming out from the coupling hole 12 to the proximal end side. 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.

  Furthermore, in the case of this example, in the normal state, these yokes 22 are laid over the inner peripheral portion of the base end surface of the yoke 10 and the portion near the distal end of the outer peripheral surface of the shaft 11. 10 and the shaft 11 are welded. In the case of this example, the small-diameter female serration portion 14 and the large-diameter male serration portion are included during normal operation, including the stationary operation {operation of the steering wheel 4 (see FIG. 24) performed while the vehicle is stopped). Torque is transmitted between the yoke 10 and the shaft 11 through the serration engaging part 19 and the weld metal 22. The strength of the weld metal 22, which is a welded portion, is not damaged by the torque (normal maximum transmission torque) acting on the stationary operation, and the yoke 10 and the shaft 11 are associated with a collision accident or a curb ride on the steering wheel. The size is such that it is damaged by a relative impact load in the rotational direction or axial direction acting between the two.

  When the vehicle equipped with the torque transmission device for a steering device of the present example configured as described above causes a collision accident or rides on a steered wheel on a curb due to an error in driving operation, the yoke 10 and the shaft 11 If a relative impact load in the rotational direction or the axial direction that exceeds the impact resistance of the weld metal 22 acts on the weld metal 22, the weld metal 22 is damaged. At the same time, a certain amount of plastic deformation occurs in the serration engaging portion between the small diameter female serration portion 14 and the large diameter male serration portion 19, and the tightening margin of the serration engaging portion is reduced or lost. If the vehicle continues to run in this state, the serration engaging portion slips in the axial direction due to, for example, repeated steering torque applied to the connecting portion between the yoke 10 and the shaft 11. As a result, as shown in the order of FIG. 3 to FIG. 5, the positional relationship between the yoke 10 and the shaft 11 in the axial direction changes from the regular positional relationship to a positional relationship shifted by a predetermined amount in the axial direction. To do. As a result, as shown in detail in FIG. 5 and FIG. 6A, the small-diameter female serration portion 14 and the small-diameter male serration portion 18 are serrated and engaged with a gap fit. As shown in detail in (B), the large-diameter female serration portion 15 and the leading half of the large-diameter male serration portion 19 are in serrated engagement with a gap fit. That is, in the abnormal state shown in FIGS. 5 to 6, the female serration portion 13 and the male serration portion 17 are engaged with each other so as to be able to transmit torque in a state where the rotation direction is unstable. It becomes a state. In this state, the coupling flange 16 is prevented from coming out of the coupling hole 12 to the proximal end side based on the mechanical engagement of the caulking portion 20 and the stepped portion 21 in the axial direction. .

  As described above, when the serration engaging portion between the female serration portion 13 and the male serration portion 17 is in a state where rattling occurs in the rotational direction, the play of the steering wheel 4 increases by the amount of the rattling. In some cases, the vibration generated based on the rattling is transmitted to the steering wheel 4 or the noise generated based on the rattling is echoed in the vehicle interior. Since such a change in the situation can be easily felt by the driver, the driver can easily recognize the fact that the impact load has been applied based on such a change in the situation. 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]
FIGS. 7-11 has shown the 2nd example of embodiment of this invention corresponding to Claim 1, 2, 4, 7-9. In the case of this example, the cross-sectional shape of the coupling hole 12a provided at the proximal end portion of the yoke 10a and the cross-sectional shape of the coupling flange portion 16a provided at the distal end portion of the shaft 11a are substantially oval. That is, the inner peripheral surface of the coupling hole 12a, which is the outer diameter side engaging portion, is a pair of plane portions 23a (23b) and 23a (23b) parallel to each other, and both the plane portions 23a (23b) and 23a. The end portions of (23b) are connected to each other, and each comprises a partially cylindrical concave curved surface portion 24, 24 centering on the central axis of the coupling hole 12a. Further, in such a coupling hole 12a, the axially leading half (the left half in FIGS. 7 and 9) is a narrow hole 25 having a relatively narrow distance between the flat surfaces 23a and 23a. The direction base half portion (the right half portion in FIGS. 7 and 9) is a wide hole portion 26 in which the distance between the flat portions 23b and 23b is relatively wide. On the other hand, the outer peripheral surface of the coupling flange portion 16a, which is the inner diameter side engaging portion, is a pair of parallel flat portions 27a (27b) and 27a (27b) and both flat portions 27a (27b) and 27a ( 27b) are connected to each other, and each comprises a partially cylindrical convex curved surface portion 28, 28 centering on the central axis of the coupling flange portion 16a. In such a coupling flange portion 16a, the axially leading end portion (the left end portion in FIGS. 7 and 9) is a narrow flange portion 29 in which the distance between the flat surface portions 27a and 27a is relatively narrow, and the axially intermediate portion. The base end portion (the right end portion in FIGS. 7 and 9) is a wide flange portion 30 in which the distance between the flat portions 27b and 27b is relatively wide.

  Further, in the case of this example, the both convex curved surface portions 28, 28 of the coupling flange portion 16a can be fitted into the both concave curved surface portions 24, 24 of the coupling hole 12a with a gap fit. Further, the wide flange 30 can be fitted into the narrow hole 25 in a state where a tightening margin is provided between the two flat surfaces 27b and 23a. The wide flange 30 can be fitted into the wide hole 26 with a relatively large gap interposed between the flat portions 27b and 23b. Further, the narrow flange portion 29 can be fitted into the narrow hole portion 25 in a state where a relatively large gap is interposed between the two flat surface portions 27a and 23a.

  In the case of this example, the normal state shown in FIGS. 7 to 8, that is, the coupling flange 16a is inserted inside the coupling hole 12a, and the yoke 10a and the shaft 11a are connected to each other in the axial direction. Torque can be transmitted in a state in which the positional relationship is a regular positional relationship, with the inner peripheral surface of the coupling hole 12a and the outer peripheral surface of the coupling flange portion 16a being free from rotational backlash. Is engaged (non-circular fitting). For this purpose, specifically, as shown in FIG. 7A and FIG. 8A, the wide flange portion 30 is inserted into the narrow hole portion 25 between the flat portions 23a and 27b. It is fitted in a state with In this state, as shown in FIG. 7 and FIG. 8 (B), the wide collar portion 30 is disposed in the wide hole portion 26, and a relatively large gap is formed between the two flat surface portions 23b and 27b. It is fitted in an intervening state.

  Also in the case of this example, the biconvex curved surface portion of the narrow flange portion 29 in the normal state or at least the tip edge portion of the narrow flange portion 29 protrudes from the coupling hole 12a. Caulking portions 20a and 20a are formed at the leading edge portions of 28 and 28 to prevent the removal. Further, the yoke 10a and the shaft 11a are welded (coupled by a weld metal 22) in the normal state.

In the case of the torque transmission device for a steering device of the present example configured as described above, the yoke 10a and the yoke 10a can be used in the normal state shown in FIGS. If a relative impact load in the rotational direction or the axial direction that exceeds the impact resistance of the weld metal 22 acts between the shaft 11a and the weld metal 22, the weld metal 22 is damaged. At the same time, a certain amount of plastic deformation occurs in the fitting portion between the narrow hole portion 25 and the wide flange portion 30, and the tightening margin of the fitting portion is reduced or lost. If the vehicle continues to run in this state, the fitting portion is slipped in the axial direction due to repeated application of steering torque to the connecting portion between the yoke 10a and the shaft 11a. As a result, as shown in the order of FIGS. 7 to 9, the yoke 10a and the shaft 11a are relatively displaced by a predetermined amount in the axial direction. As a result, as shown in FIG. 9 and FIG. 10A, the narrow hole 25 and the narrow flange 29 have a relatively large gap between the flat portions 23a and 27a. It will be in the state fitted in the interposed state. At the same time, as shown in FIG. 9 and FIG. 10B, the wide hole portion 26 and the wide flange portion 30 are provided with a relatively large gap between the flat portions 23b and 27b. It will be in the state fitted in the state. In such an abnormal state, as shown by chain lines in FIGS. 10 (A) and 10 (B), the coupling flange 16a is slightly inside the coupling hole 12a based on the presence of the gaps. Become rotatable. That is, in this state, the inner peripheral surface of the coupling hole 12a and the outer peripheral surface of the coupling flange portion 16a are engaged with each other so that torque can be transmitted (non-circular fitting) in a state where the rotational direction is unstable. It will be in the state. In this state, the coupling flange 16a is pulled out from the coupling hole 12a to the proximal end side, as shown in FIG. 11, in the caulking portions 20a and 20a and the opening portion on the distal end side of the coupling hole 12a. The step portion 21 existing in the surrounding portion is prevented from being mechanically engaged in the axial direction.
In the case of the torque transmission device for a steering device of this example as described above, the driver can easily recognize the fact that the impact load is applied based on the presence of the rattling as described above.

[Third example of embodiment]
FIGS. 12-16 has shown the 3rd example of embodiment of this invention corresponding to Claim 1, 2, 5, 7-9. In the case of this example, a configuration is adopted in which the coupling hole 12b provided at the proximal end portion of the yoke 10b and the coupling flange portion 16b provided at the distal end portion of the shaft 11b are key-engaged. That is, in the case of this example, the inner peripheral surface of the coupling hole 12b, which is the outer diameter side engaging portion, is the outer diameter side cylindrical surface portion 31 whose diameter does not change in the axial direction, and the outer diameter side cylindrical surface portion 31. The key 32 is provided so as to protrude from the circumferential portion to the inner diameter side and is long in the axial direction. The key 32 has an axially leading half (left half in FIGS. 12, 13, and 15) as a wide key 33 having a relatively wide circumferential width, and an axial base half (see FIGS. 12, 13, and 15). 15 is a narrow key portion 34 having a relatively narrow circumferential width. On the other hand, the outer peripheral surface of the coupling flange portion 16b, which is the inner diameter side engaging portion, is provided on the inner diameter side cylindrical surface portion 35 whose diameter dimension does not change in the axial direction and a part of the inner diameter side cylindrical surface portion 35 in the circumferential direction. It consists of a key groove 36 that is long in the axial direction. The key groove 36 has an axial front end portion (left half portion in FIGS. 12, 13 and 15) as a wide groove portion 37 having a relatively wide circumferential width, and an axial intermediate portion to a base end portion (FIG. 12, FIG. 12). The right end portions 13 and 15 are narrow groove portions 38 having a relatively narrow circumferential width.

  In the case of this example, the inner diameter side cylindrical surface portion 35 can be fitted into the outer diameter side cylindrical surface portion 31 with a gap fit. In addition, the wide key portion 33 is in a state where the circumferential groove is provided with respect to the narrow groove portion 38 and a circumferential gap is interposed between the wide groove portion 37 and the key engagement. Is possible. The narrow key portion 34 can be key-engaged with the narrow groove portion 38 interposed with a circumferential clearance.

  In the case of this example, the normal state shown in FIGS. 13 to 14, that is, the coupling flange 16 b is inserted inside the coupling hole 12 b, and the yoke 10 b and the shaft 11 b are connected to each other in the axial direction. Torque can be transmitted in a state where the positional relationship is a regular positional relationship, with the inner circumferential surface of the coupling hole 12b and the outer circumferential surface of the coupling flange portion 16b being free from a backlash in the rotational direction. Is engaged. Specifically, as shown in FIGS. 13 and 14A, the wide key portion 33 is provided with a margin in the circumferential direction at the front half of the narrow groove portion 38. Engaged. Further, in this state, as shown in FIGS. 13 and 14B, the base half of the narrow key portion 34 is engaged with the narrow groove portion 38 with a circumferential clearance interposed therebetween. I am letting.

  Also in the case of this example, the tip edge portion of the outer peripheral surface of the coupling flange portion 16b in the normal state or at least the tip edge portion of the coupling flange portion 16b protrudes from the coupling hole 12b. Of these, a caulking portion 20b is formed at a portion deviated from the key groove 36 with respect to the circumferential direction. Further, the yoke 10b and the shaft 11b are welded (coupled by a weld metal 22) in the normal state.

In the case of the torque transmission device for a steering device of the present example configured as described above, the yoke 10b and the above-mentioned yoke 10b in the normal state shown in FIGS. When a relative impact load in the rotational direction or the axial direction that exceeds the impact resistance of the weld metal 22 acts on the shaft 11b, the weld metal 22 is damaged. At the same time, a certain amount of plastic deformation occurs in the engaging portion between the first half of the narrow groove portion 38 and the wide key portion 33, and the tightening margin of the engaging portion is reduced or lost. If the vehicle continues to run in this state, the engaging portion slips in the axial direction due to, for example, repeated application of steering torque to the connecting portion between the yoke 10b and the shaft 11b. As a result, as shown in the order of FIG. 13 to FIG. 15, the yoke 10b and the shaft 11b are relatively displaced by a predetermined amount in the axial direction. As a result, as shown in FIGS. 15 and 16A, the wide groove portion 37 and the wide key portion 33 are engaged with each other with a gap in the circumferential direction interposed therebetween. At the same time, as shown in FIGS. 15 and 16B, the first half of the narrow groove portion 38 and the narrow key portion 34 are engaged with each other with a circumferential gap interposed therebetween. It becomes. That is, in such an abnormal state, the inner peripheral surface of the coupling hole 12b and the outer peripheral surface of the coupling flange portion 16b are engaged with each other so that torque can be transmitted in a state where the rotational direction is unstable. It will be in the state. In this state, the coupling flange 16b is pulled out from the coupling hole 12b to the proximal end side when the caulking portion 20 and the stepped portion 21 existing around the opening portion on the distal end side of the coupling hole 12b. Is prevented based on mechanical engagement in the axial direction.
In the case of the torque transmission device for a steering device of this example as described above, the driver can easily recognize the fact that the impact load is applied based on the presence of the rattling as described above.

[Fourth Example of Embodiment]
FIGS. 17-21 has shown the 4th example of embodiment of this invention corresponding to Claim 1, 2, 6-9. Also in this example, a configuration is adopted in which the coupling hole 12c provided in the proximal end portion of the yoke 10c and the coupling flange portion 16c provided in the distal end portion of the shaft 11c are key-engaged. In the case of this example, a key 32a that is long in the axial direction is provided on a part of the inner circumferential surface of the coupling hole 12c, which is an outer diameter side engaging portion, so as to protrude toward the inner diameter side. The circumferential width of the key 32a does not change with respect to the axial direction. Of the inner peripheral surface of the coupling hole 12c, the portion removed from the key 32a has a stepped cylindrical shape. That is, the portion of the inner peripheral surface of the coupling hole 12c that is removed from the key 32a is the axially leading half (the left half in FIGS. 17, 18, and 20), and the diameter is relatively small. The outer diameter side small diameter cylindrical portion 39 is used, and the axial intermediate portion or the base half portion (the right half portion in FIGS. 17, 18, and 20) is the outer diameter side large diameter cylindrical portion 40 having a relatively large diameter. On the other hand, the outer peripheral surface of the coupling flange portion 16c, which is the inner diameter side engaging portion, is provided with a key groove 36a that is long in the axial direction in a part of the circumferential direction. The circumferential width of the key groove 36a is not changed in the axial direction. Of the outer peripheral surface of the coupling flange portion 16c, the portion removed from the key groove 36a has a stepped cylindrical shape. That is, of the outer peripheral surface of the coupling flange portion 16c, the portion removed from the key groove 36a is the axial tip (the left end portion in FIGS. 17, 18 and 20), and the inner diameter is relatively small. A side small-diameter cylindrical portion 41 is used, and an axially intermediate portion or a base end portion (right end portion in FIGS. 17, 18, and 20) is an inner diameter-side large-diameter cylindrical portion 42 having a relatively large diameter.

  In the case of this example, the inner diameter side large diameter cylindrical portion 42 is an interference fit with the outer diameter side small diameter cylindrical portion 39 and a clearance fit with the outer diameter side large diameter cylindrical portion 40. It can be fitted. The inner diameter side small diameter cylindrical portion 41 can be fitted into the outer diameter side small diameter cylindrical portion 39 with a gap fit. The key 32a can be key-engaged in a state where a circumferential gap is interposed with respect to the key groove 36a.

  In the case of this example, the normal state shown in FIGS. 18 to 19, that is, the coupling flange 16c is inserted inside the coupling hole 12c, and the yoke 10c and the shaft 11c are mutually connected in the axial direction. Torque can be transmitted in a state where the positional relationship is a regular positional relationship, with the inner circumferential surface of the coupling hole 12c and the outer circumferential surface of the coupling flange portion 16c being free from rotational backlash. Is engaged. Specifically, as shown in FIGS. 18 and 19A, the key 32a is engaged with the key groove 36a with a gap in the circumferential direction interposed therebetween, and the outer diameter is set. The front half of the inner diameter side large diameter cylindrical portion 42 is fitted into the side small diameter cylindrical portion 39 with an interference fit. Further, the yoke 10c and the shaft 11c are welded (coupled by a weld metal 22). In the case of this example, the fitting part (friction engagement part) between the outer diameter side small diameter cylindrical part 39 and the inner diameter side large diameter cylindrical part 42 and the welding are performed during normal operation including during stationary operation. Torque is transmitted between the yoke 10c and the shaft 11c through the metal 22 (mainly through the weld metal 22).

  Also in the case of this example, the tip edge portion of the outer peripheral surface of the coupling flange portion 16c in the normal state or at least the tip edge portion of the coupling flange portion 16c protrudes from the coupling hole 12c. Of these, a caulking portion 20c is formed at a portion deviating from the key groove 36a with respect to the circumferential direction.

In the case of the torque transmission device for a steering device of the present example configured as described above, the yoke 10c and the above-mentioned yoke 10c can be used in the normal state shown in FIGS. When a relative impact load in the rotational direction or the axial direction that exceeds the impact resistance of the weld metal 22 acts on the shaft 11c, the weld metal 22 is damaged. At the same time, a certain amount of plastic deformation occurs in the fitting portion between the outer diameter side small diameter cylindrical portion 39 and the tip half portion of the inner diameter side large diameter cylindrical portion 42, and the tightening margin of the fitting portion is reduced or To lose. If the vehicle continues to run in this state, the engagement portion will slip in the axial direction due to, for example, repeated steering torque applied to the joint between the yoke 10c and the shaft 11c. As a result, as shown in the order of FIG. 18 → FIG. 20, the yoke 10c and the shaft 11c are relatively displaced by a predetermined amount in the axial direction. As a result, as shown in FIG. 20A and FIG. 21A, the outer diameter side small diameter cylindrical portion 39 and the inner diameter side small diameter cylindrical portion 41 are fitted with a gap fit, and FIG. As shown in FIG. 21B, the outer diameter side large diameter cylindrical portion 40 and the inner half side large diameter cylindrical portion 42 are in a state of being fitted with a gap fit. On the other hand, even in this state, the state in which the key groove 36a and the key 32a are engaged through a circumferential gap is maintained. That is, in this abnormal state, the inner peripheral surface of the coupling hole 12c and the outer peripheral surface of the coupling flange portion 16c are engaged with each other so as to be able to transmit torque in a state where the rotational direction is unstable. It becomes. In this state, the coupling flange portion 16c coming out from the coupling hole 12c to the proximal end side is caused by the caulking portion 20c and the stepped portion 21 existing around the opening portion on the distal end side of the coupling hole 12c. Is prevented based on mechanical engagement in the axial direction.
In the case of the torque transmission device for a steering device of this example as described above, the driver can easily recognize the fact that the impact load is applied based on the presence of the rattling as described above.

[Fifth Example of Embodiment]
FIG. 22 shows a fifth example of an embodiment of the present invention corresponding to claims 1 to 3 and 7 to 9. In the case of this example, the shaft 11d has a circular tube shape. At the same time, the leading edge portion of the coupling flange portion 16d provided at the leading end portion of the shaft 11d is bent to the outer diameter side by rolling caulking so that the bent portion is caulked portion 20d for retaining. It is said. The structure and operation of the other parts are the same as those in the first example of the embodiment shown in FIGS. For this reason, the same code | symbol is attached | subjected to an equivalent part and the overlapping illustration and description are abbreviate | omitted.

[Sixth Example of Embodiment]
FIG. 23 shows a sixth example of an embodiment of the present invention corresponding to claims 1 to 3 and 7 to 9. In the case of this example, prior to inserting the coupling flange portion 16e provided at the distal end portion of the shaft 11e into the coupling hole 12d provided at the proximal end portion of the yoke 10d, the outer periphery of the coupling flange portion 16e is inserted. A second large-diameter male serration portion 43 is provided at the tip of the surface. The pitch circle diameter of the second large-diameter male serration portion 43 is slightly larger than the pitch circle diameter of the large-diameter male serration portion 19 provided at the proximal end portion of the outer peripheral surface of the coupling flange portion 16e.

  In the case of this example, when inserting the coupling flange 16e inside the coupling hole 12d, by applying a large press-fitting load to the shaft 11e, the second large-diameter male serration portion 43 is replaced with a small-diameter female serration portion. 14 and press the inside of the small-diameter female serration portion 14. Then, as shown in the figure, the second large-diameter male serration portion 43 is serrated to the large-diameter female serration portion 15 with a gap fit, and the large-diameter male serration portion 19 is connected to the small-diameter female serration portion 14. The serration is engaged with an interference fit.

  In the case of this example, in this state, after a relative impact load in the rotational direction or the axial direction acts between the yoke 10d and the shaft 11e, the vehicle continues to run, so that the coupling hole 12d When the connecting flange portion 16e is displaced from the inside in a direction of coming out to the proximal end side, the proximal end edge of the second large-diameter male serration portion 43 and the distal end edge of the small-diameter female serration portion 14 are machined in the axial direction. Engaging. This prevents further displacement in the exit direction. In the case of this example, the base end edge of the second large-diameter male serration portion 43 and the distal end edge of the small-diameter female serration portion 14 correspond to the retaining structure portion. The structure and operation of the other parts are the same as those in the first example of the embodiment shown in FIGS. For this reason, the same code | symbol is attached | subjected to an equivalent part and the overlapping illustration and description are abbreviate | omitted.

The present invention is not limited to the coupling portion between the shaft and the universal joint yoke, and any portion may be used as long as it constitutes a steering device and transmits torque applied to the steering wheel to the input shaft of the steering gear unit. But it can be done. 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.
Moreover, when practicing the present invention, the strength of the welded portion between the first and second torque transmitting members can be set to an arbitrary magnitude, but the durability against impact load increases as the strength of the welded portion increases. Can be ensured and it is easy to continue safe driving after receiving an impact load. Also in this case, when the welded portion is damaged by applying an impact load larger than expected, the impact load detection function according to the present invention works (by interfering with the rattling in the rotational direction, Transition to a coupled state where torque transmission is possible).
In the case of carrying out the present invention, if the welding between the first and second torque transmitting members is omitted, both the first and second torques during normal operation, including during the stationary operation, are used. The torque transmission between the transmission members and the axial displacement between the first and second torque transmission members are determined based on the engagement between the outer diameter side engaging portion and the inner diameter side engaging portion. Appropriately regulate the shape and dimensions of each part so that it can be done.
Further, in each of the above-described embodiments, the transition direction from the normal state to the abnormal state of the coupling portion between the first and second torque transmission members is changed to the coupling portion between the first and second torque transmission members. It was set as the extension direction. However, when carrying out the present invention, the transition direction can be the contraction direction (anti-extension direction) of the coupling portion. In this case, for example, the structure of the outer diameter side engaging portion and the inner diameter side engaging portion is reversed with respect to the axial direction in the structure of each of the embodiments. Furthermore, both the structure which set the said transfer direction to both directions, ie, the structure which notifies abnormality when the said connection part transfers to an expansion | extension direction, and the structure which notifies abnormality when it similarly transfers to a contraction direction were provided. A structure can also be adopted.

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-10d Yoke 11, 11a-11e Shaft 12, 12a-12d Joint hole 13 Female serration Part 14 Small-diameter female serration part 15 Large-diameter female serration part 16, 16a to 16e Coupling collar part 17 Male serration part 18 Small-diameter male serration part 19 Large-diameter male serration part 20, 20a to 20d Caulking part 21 Step part 22 Weld metal 23a, 23b Plane part 24 Concave surface part 25 Narrow hole part 26 Wide hole part 27a, 27b Plane part 28 Convex curve part 29 Narrow flange part 30 Wide collar part 31 Outer diameter side cylindrical surface part 32, 32a Key 33 Wide key part 34 Narrow Within key part 35 Side cylindrical surface portion 36,36a keyway 37 wide groove 38 narrow groove 39 outer diameter small-diameter cylindrical portion 40 the outer diameter side large-diameter cylindrical portion 41 the inner diameter side small-diameter cylindrical portion 42 the inner diameter side large-diameter cylindrical portion 43 second large 径雄 serration portion

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 the torque transmission device for a steering device that is provided for torque transmission between the steering wheel and the input shaft, the first and second torque transmission members have a backlash in the rotational direction. Is coupled so that torque can be transmitted without causing vibration, and is coupled so as to be able to transmit torque with a backlash in the rotational direction based on relative displacement in the axial direction by a predetermined amount. A torque transmission device for a steering device characterized by changing to The first torque transmission member has a coupling hole and an outer diameter side engaging portion provided on the inner peripheral surface of the coupling hole,
The second torque transmission member is capable of transmitting torque to the coupling flange portion inserted inside the coupling hole and the outer diameter side engagement portion provided on the outer peripheral surface of the coupling flange portion. Having a combined inner diameter side engaging portion,
The state in which the first and second torque transmission members are coupled so as to be able to transmit torque without causing a backlash in the rotational direction refers to the axial direction of the first and second torque transmission members. In a state where the mutual positional relationship is a normal positional relationship, the outer diameter side engaging portion and the inner diameter side engaging portion are engaged with each other so as to be able to transmit torque without causing backlash in the rotational direction. Is a state in which the first and second torque transmission members are coupled to each other so as to be able to transmit torque with backlash in the rotational direction. In the state where the mutual positional relationship with respect to the axial direction is a positional relationship deviated by a predetermined amount from the regular positional relationship in the action direction, the outer diameter side engaging portion and the inner diameter side engaging portion are in the rotational direction. It is in a state where it is engaged so as to be able to transmit torque with rattling,
Between the first and second torque transmitting members, there is provided a retaining structure portion for preventing the coupling flange portion from coming out of the coupling hole.
The torque transmission device for a steering device according to claim 1.   The torque transmission device for a steering device according to claim 2, wherein an engagement mode between the outer diameter side engagement portion and the inner diameter side engagement portion that enables torque transmission is serration engagement.   The torque transmission device for a steering device according to claim 2, wherein an engagement mode between the outer diameter side engaging portion and the inner diameter side engaging portion that enables torque transmission is a non-circular fitting.   The torque transmission device for a steering apparatus according to claim 2, wherein an engagement mode between the outer diameter side engagement portion and the inner diameter side engagement portion that enables torque transmission is key engagement.   The engagement mode of the outer diameter side engaging portion and the inner diameter side engaging portion that enables transmission of torque without causing backlash in the rotational direction is frictional engagement. The torque transmission device for a steering device according to claim 2, wherein the engagement mode that enables torque transmission by interposing any one of serration engagement, non-circular fitting, and key engagement.   The retaining structure prevents the coupling flange from coming out of the coupling hole based on mechanical engagement of the first and second torque transmitting members in the axial direction. The torque transmission device for a steering device according to any one of claims 2 to 6.   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 2 to 7, wherein the torque transmission member is a shaft, and the coupling flange portion is provided at an end portion of the shaft. The first and second torque transmission members are welded to each other in a state where the torque transmission members are coupled so as to be able to transmit torque without causing backlash in the rotational direction. The torque transmission device for a steering device according to item 1.

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