JP7434820B2 - Intermediate shaft for steering device and steering device - Google Patents

Description

The present invention relates to an intermediate shaft for a steering device and a steering device.

In a steering device for a large vehicle such as a large truck, for example, as shown in FIG. is being communicated to. The intermediate shaft 103 has a shaft end connected to a shaft to be connected via universal joints 104a and 104b.

The intermediate shaft 103 has a structure that can be expanded and contracted in the axial direction by, for example, engaging a female spline portion formed on the inner peripheral surface of the female shaft 106 and a male spline portion formed on the outer peripheral surface of the male shaft 107. have. Thereby, the female shaft 106 and the male shaft 107 are combined to enable torque transmission and relative movement in the axial direction.

A typical large truck includes a tilt shaft 109 that rotatably supports the front end of a cabin (driver's cab) 108 with respect to a chassis frame (not shown). As shown by the two-dot chain line in FIG. 15, by pivoting the cabin 108 forward about the tilt axis 109, the cab is tilted so that the engine part of the vehicle is exposed to the outside.
When the cab is tilted in this manner, the female shaft 106 and the male shaft 107 move relative to each other in the axial direction, increasing the overall length of the intermediate shaft 103, thereby increasing the distance between the steering shaft 102 and the steering gear unit 105. is allowed. In order to realize this cab tilt state, it is necessary to ensure a large expansion and contraction stroke of the intermediate shaft 103.

However, in the intermediate shaft 103 which is a combination of two split shafts, the female shaft 106 and the male shaft 107, as described above, it is necessary to increase the axial length of each split shaft in order to ensure a large expansion and contraction stroke. In this case, especially regarding the male shaft 107, it becomes difficult to press-form with high productivity, and as it becomes longer, it becomes easier to bend, so a process to straighten the bend is required, etc. There are many factors that increase costs.

Furthermore, when a bending moment is applied to the intermediate shaft 103 due to an external force applied while the vehicle is running, the maximum radial displacement of the intermediate shaft 103 occurs at the joint between the female shaft 106 and the male shaft 107, causing the joint to bend. It is rotated in this state. As a result, the intermediate shaft 103 tends to run out, causing vibrations and abnormal noises. In addition, the increase in sliding resistance at the connecting portion also makes stick-slip more likely to occur, which also promotes the generation of vibrations and abnormal noises.

On the other hand, Patent Document 1 describes an intermediate shaft having three split shafts. This intermediate shaft consists of a cylindrical large-diameter shaft, a cylindrical medium-diameter shaft whose outer circumferential surface is spline-engaged with the inner circumferential surface of the large-diameter shaft, and a cylindrical medium-diameter shaft whose outer circumferential surface is spline-engaged with the inner circumferential surface of the medium-diameter shaft. and a small diameter shaft. An intermediate shaft that combines three split shafts (large diameter shaft, medium diameter shaft, small diameter shaft) has the same size as an intermediate shaft that combines two split shafts (female shaft, male shaft). Even when securing a long expansion/contraction stroke, the axial dimension of each split shaft can be reduced.

Japanese Patent Application Publication No. 2003-146225

However, in the intermediate shaft of Patent Document 1, the split shaft located in the middle of the three split shafts fits with the other split shaft connected to both ends of the split shaft on both the inner and outer circumferential surfaces. It is the composition. Therefore, there is a problem in that the accuracy of the connecting portions such as splines and the cost for ensuring the accuracy increase.

SUMMARY OF THE INVENTION Therefore, the present invention provides an intermediate shaft for a steering device and a steering device that can suppress an increase in cost, suppress swinging due to bending of the intermediate shaft even when subjected to external force, and suppress generation of vibration and abnormal noise. The purpose is to

The present invention consists of the following configuration.
(1) It has a cylindrical shape with open ends on both sides in the axial direction, and has a first female spline part on the inner peripheral surface of one axial part, and a second female spline part on the inner peripheral surface of the other axial part. a female shaft having a
a first male shaft having a first male spline portion on the outer peripheral surface of the other axial portion;
a second male shaft having a second male spline portion on the outer circumferential surface of one portion in the axial direction;
Equipped with
the first male spline portion of the first male shaft is spline engaged with the first female spline portion of the female shaft;
the second male spline portion of the second male shaft is press-fitted into spline engagement with the second female spline portion of the female shaft;
A sliding load of the first male shaft with respect to the female shaft is smaller than a sliding load of the second male shaft with respect to the female shaft.
Intermediate shaft for steering device.
(2) Steering gear unit;
steering wheel and
The intermediate shaft for a steering device according to (1), which is provided between the steering gear unit and the steering wheel;
A steering device comprising:

According to the present invention, it is possible to suppress an increase in cost, and to suppress swinging due to bending of the intermediate shaft even when external force is applied, and to suppress generation of vibration and abnormal noise.

FIG. 2 is a perspective view of an intermediate shaft for a steering device according to the present embodiment. FIG. 3 is a cross-sectional view along the axial direction of the intermediate shaft for a steering device according to the present embodiment. FIG. 3 is a perspective view of the female shaft taken in section in the axial direction. It is a perspective view of a 1st male shaft. It is a perspective view of a 2nd male shaft. 3 is a diagram showing the cross-sectional shape of the intermediate shaft for a steering device at each position in the axial direction, in which (A) is a cross-sectional view taken along line II in FIG. 2, (B) is a cross-sectional view taken along line II-II in FIG. 2, and (C) is a cross-sectional view taken along line II-II in FIG. ) is a sectional view taken along III-III in FIG. 2, and (D) is a sectional view taken along IV-IV in FIG. FIG. 3 is a cross-sectional view along the axial direction showing a tilted-up state of the intermediate shaft for the steering device. FIG. 3 is a cross-sectional view along the axial direction showing the shortest nominal state of the intermediate shaft for the steering device. FIG. 3 is a cross-sectional view along the axial direction showing a fully collapsed state of the intermediate shaft for the steering device. FIG. 3 is a diagram illustrating a retainer provided on the second male shaft, in which (A) is a radial cross-sectional view of the female shaft main body in the intermediate shaft for the steering device, and (B) is a sectional view of the second male shaft in the intermediate shaft for the steering device. FIG. 2 is a cross-sectional view along the axial direction near the end of one axial portion of the male shaft. FIG. 3 is a diagram illustrating a state in the middle of insertion of the second male shaft into the second female spline cylinder part, in which (A) is a radial cross-sectional view of the female shaft main body in the intermediate shaft for the steering device, and (B) is a steering FIG. 2 is a cross-sectional view along the axial direction near the end of one axial portion of the second male shaft in the device intermediate shaft. FIG. 3 is a diagram illustrating the operation of the intermediate shaft for the steering device in each mounting direction, in which (A) is a schematic configuration diagram showing a state in which the first male shaft is directed toward the steering gear unit, and (B) is a diagram illustrating the first male shaft. FIG. 3 is a schematic configuration diagram showing a state in which the shaft is directed toward the steering wheel. FIG. 3 is a schematic diagram illustrating the wobbling that occurs in the intermediate shaft for the steering device. FIG. 3 is a diagram showing an intermediate shaft for a steering device in which a first female spline portion and a second female spline portion of the female shaft are arranged in different phases in the circumferential direction, and (A) is a front view from the first male shaft side. In the figure, (B) is a side view, and (C) is a front view from the second male shaft side. FIG. 1 is a partially cutaway side view showing an example of a conventionally known steering device for a large truck.

Embodiments of the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a perspective view of an intermediate shaft for a steering device according to this embodiment. FIG. 2 is a cross-sectional view along the axial direction of the intermediate shaft for a steering device according to the present embodiment.

As shown in FIGS. 1 and 2, the intermediate shaft 1 for a steering device according to the present embodiment includes yokes 3 at both ends. This intermediate shaft for a steering device (hereinafter referred to as intermediate shaft) 1 is a rotating shaft that is incorporated into a steering device of a large truck or the like and transmits the movement of a steering shaft 102 to a steering gear unit 105 (see FIG. 15). When the steering device is mounted on a vehicle, the intermediate shaft 1 is inserted into a through hole formed in a panel that partitions the interior of the vehicle and the exterior of the vehicle, and the respective ends are disposed inside and outside the vehicle. That is, the steering device includes a steering gear unit 105 shown in FIG. 15, a steering wheel 101, and an intermediate shaft 1 provided between the steering gear unit 105 and the steering wheel 101.

The intermediate shaft 1 includes a female shaft 10, a first male shaft 30, and a second male shaft 40. The first male shaft 30 is assembled to the female shaft 10 at one axial portion (the left side in FIG. 2), and the second male shaft 40 is assembled to the other axial portion (the right side in FIG. 2). Flexible bellows-shaped boots 5 may be attached to the first male shaft 30 and the second male shaft 40, respectively, and these boots 5 allow the first male shaft 30 and the second male shaft 40 to The outer circumferential side of is covered. In addition, when the intermediate shaft 1 is arranged to pass through a dash panel (not shown) or the like, there is a space between the outer peripheral surface of the intermediate shaft 1 and the through hole of the dash panel as a sealing member that separates the interior of the vehicle from the outside of the vehicle. It is preferable to arrange a dust cover (not shown). The dust cover is arranged at the center of the intermediate shaft 1 in the axial direction. In the axial center of the intermediate shaft 1 of this configuration, the female shaft 10 that does not expand or contract and has few protrusions etc. is arranged, so the above-mentioned dust cover can be freely arranged and the layout of the dust cover can be improved. .

FIG. 3 is a perspective view of the female shaft 10 taken in section in the axial direction.
The female shaft 10 is formed into a cylindrical shape with open ends on both sides in the axial direction. The female shaft 10 has a female shaft main body 11 , a first female spline cylindrical portion 13 , and a second female spline cylindrical portion 15 . The first female spline cylinder part 13 is provided on one part of the female shaft main body 11, and the second female spline cylinder part 15 is integrally provided on the other part of the female shaft main body 11.

The first female spline cylinder part 13 and the second female spline cylinder part 15 are each formed to have a smaller outer diameter than the female shaft main body 11. The first female spline cylinder part 13 of this configuration is connected to the female shaft main body 11 by welding, and the second female spline cylinder part 15 is integrally molded with the female shaft main body 11. 13 and the second female spline cylindrical portion 15 with the female shaft main body 11 are not limited to this.

The female shaft main body 11 of the female shaft 10 is formed into a cylindrical shape (see (C) of FIG. 6). Further, a first female spline portion 17 is formed on the inner peripheral surface of the first female spline cylinder portion 13 . A second female spline portion 19 is formed on the inner peripheral surface of the second female spline cylinder portion 15 . The first female spline portion 17 and the second female spline portion 19 are each formed along the axial direction. In the intermediate shaft 1 described above, the female shaft 10 has the first male shaft 30 and the second male shaft 40 disposed in the same phase in the circumferential direction by the first female spline portion 17 and the second female spline portion 19. It is now possible.

Further, the female shaft 10 has a stepped portion 21 . The stepped portion 21 is provided closer to the second female spline portion 19 between the first female spline portion 17 and the second female spline portion 19 . Specifically, the second female spline is formed in the female shaft body 11 between the first female spline cylinder part 13 having the first female spline part 17 and the second female spline cylinder part 15 having the second female spline part 19. A stepped portion 21 is formed at the end on the cylindrical portion 15 side. The stepped portion 21 has a tapered surface that expands in diameter from the second female spline cylinder portion 15 toward one portion in the axial direction.

FIG. 4 is a perspective view of the first male shaft.
The first male shaft 30 is formed into a solid rod shape, and the yoke 3 is fixed to one part in the axial direction by welding. The first male shaft 30 has a first male spline portion 31 on the outer circumferential surface of the other axial portion. The surface of the first male spline portion 31 is covered with a first coating layer made of synthetic resin.

As shown in FIG. 2, the first male shaft 30 is inserted into the first female spline cylinder portion 13 of the female shaft 10, and the first male spline portion 31 is splined to the first female spline portion 17 of the female shaft 10. engage. The first spline engaging portion 35 in which the first female spline portion 17 and the first male spline portion 31 are engaged is lubricated with grease. The first male shaft 30 is prevented from rotating relative to the first female spline cylindrical portion 13 of the female shaft 10 and can slide in the axial direction. This slidable first spline engagement part 35 is light because the first male spline part 31 and the first female spline part 17, on which the first coating layer made of synthetic resin is formed, are lubricated with grease. It becomes possible to slide under load.

FIG. 5 is a perspective view of the second male shaft.
The second male shaft 40 is formed into a solid rod shape, and the yoke 3b is fixed to the other axial portion by welding. The second male shaft 40 has a second male spline portion 41 on its outer peripheral surface. The second male spline portion 41 is covered with a second coating layer made of synthetic resin.

As shown in FIG. 2, the second male shaft 40 is fitted into the second female spline cylindrical portion 15 of the female shaft 10, and the second male spline portion 41 is press-fitted into the second female spline portion 19 of the female shaft 10. to engage the spline. Grease is applied to the second spline engaging portion 45 where the second female spline portion 19 and the second male spline portion 41 are engaged. The grease has the effect of preventing rust and fretting in the second spline engagement portion 45. Further, the second female spline cylinder portion 15 is provided with a caulking portion 23 (see FIG. 3).

Further, the second male shaft 40 has a retainer 47 at the tip of one axial portion. The retainer 47 is fixed to the second male shaft 40 by a fastening member such as a screw 49. Details of the retainer 47 will be described later.

As described above, the intermediate shaft 1 has the cross sections shown in FIGS. 6A to 6D.
6(A) is a cross section taken along line II in FIG. 2, FIG. 6(B) is a cross section taken along line II-II in FIG. 2, and FIG. 6(C) is a cross section taken along line III in FIG. -III line cross section, and (D) of FIG. 6 is a IV-IV line cross section of FIG.

As shown in FIG. 6D, the caulking portion 23 is formed by pressing the outer peripheral surface of the second female spline cylinder portion 15 with a caulking tool (not shown). At the axial position of the caulking portion 23 of the second spline engagement portion 45, the second female spline cylinder portion 15 is slightly deformed into an elliptical shape. Thereby, the sliding load of the second male shaft 40 with respect to the second female spline cylinder portion 15 is increased. Therefore, the second male shaft 40 is prevented from rotating with respect to the second female spline cylindrical portion 15 of the female shaft 10, while being subjected to a load greater than the load at which the first spline engagement portion 35 starts sliding in the axial direction. If granted, sliding will be possible. The caulking portion 23 is formed by pressing, similar to the arc-shaped recess disclosed in, for example, Japanese Patent Laid-Open No. 8-91230.

In the intermediate shaft 1 having the above configuration, the sliding load of the first male shaft 30 with respect to the female shaft 10 is smaller than the sliding load of the second male shaft 40 with respect to the female shaft 10. The sliding load of the first male shaft 30 with respect to the female shaft 10 is, for example, in the range of 20 to 200N, whereas the sliding load of the second male shaft 40 with respect to the female shaft 10 is, for example, in the range of 500 to 3000N. It is. In this way, the second male shaft 40 is engaged with the female shaft 10 with a sliding load that is 10 times or more, preferably 20 times or more, and even more preferably 30 times or more than the sliding load of the first male shaft 30. There is. The second male shaft 40 does not slide under normal conditions, but when a large impact force is applied to the intermediate shaft 1, it slides on the female shaft 10 and becomes a damper that absorbs the impact.

Next, the expansion and contraction state of the intermediate shaft 1 accompanying the cab tilt operation will be explained.
FIG. 7 is a cross-sectional view along the axial direction showing a tilted-up state of the intermediate shaft. FIG. 8 is a cross-sectional view along the axial direction showing the shortest nominal state of the intermediate shaft. FIG. 9 is a cross-sectional view along the axial direction showing a fully collapsed state of the intermediate shaft.

(Nominal state)
First, as shown in FIG. 2, the intermediate shaft 1 in a nominal state with the cabin 108 (see FIG. 15) in a normal position is connected to the first male shaft spline-engaged with the first female spline portion 17 of the female shaft 10. A portion of 30 protrudes to one side in the axial direction (left side in FIG. 2). Similarly, in the nominal state, a portion of the second male shaft 40 that is engaged with the second female spline portion 19 of the female shaft 10 protrudes toward the other side in the axial direction (to the right in FIG. 2). In this nominal state, there is a gap between the other axial end of the first male shaft 30 and the one axial end of the second male shaft 40 in the female shaft main body 11 of the female shaft 10. It is formed. The axial length Lc of this gap is the protrusion dimension La of the first male spline part 31 from the first female spline part 17 of the female shaft 10 and the second male spline part from the second female spline part 19 of the female shaft 10. It is equal to or approximately equal to the sum of the protruding dimension Lb of the portion 41 (Lc≈La+Lb).

(Tilt up state)
Next, when the cabin 108 is rotated forward about the tilt shaft 109 (see FIG. 15), the first male shaft 30 is moved to the first female spline tube of the female shaft 10, as shown in FIG. It is pulled out from the section 13 to one side in the axial direction, and the first female spline section 17 and the first male spline section 31 are slid. Thereby, the intermediate shaft 1 is extended in the axial direction and becomes the longest state or a tilted-up state close to the longest state.

In this tilted-up state, the axial length Ld of the first spline engaging portion 35 between the first female spline portion 17 and the first male spline portion 31 is equal to the second The protruding dimension Lb of the male spline portion 41 is set larger (Ld>Lb). As a result, for example, even if the female shaft 10 is displaced to the other axial direction (right side in FIG. 7) and the protrusion dimension Lb of the second male spline portion 41 is 0, the first male shaft from the female shaft 10 The escape of 30 is suppressed. Note that as long as the axial length Ld of the first spline engagement portion 35 is at least about 10 mm, there will be no problem in transmitting the rotational torque.

(Nominal state)
Further, when the intermediate shaft 1 is tilted down from the tilted up state, the intermediate shaft 1 returns to the nominal state as shown in FIG. 2 described above. At this time, when the intermediate shaft 1 is contracted by adjusting the height of the steering wheel 101 or by an external force acting during driving, the first male shaft 30 is further pushed into the first female spline cylindrical portion 13 of the female shaft 10. This state becomes the shortest nominal state shown in FIG.

In this way, the first female spline part 17 and the first male spline part 31 slide, and the intermediate shaft 1 is further shortened. In this shortened state of the intermediate shaft 1, the axial length Lc1 from the end of the other axial part of the first male shaft 30 to the end of the one axial part of the second male shaft 40 is different from the normal one. It is shorter than the axial length Lc in the nominal state. Even in this shortest nominal state, the second female spline portion 19 of the female shaft 10 and the second male spline portion 41 of the second male shaft 40 do not slide.

(Full collapse state)
For example, if a large external force is applied to the cabin 108 (see FIG. 15), and an impact force due to a so-called secondary collision caused by the driver colliding with the steering wheel is applied to the intermediate shaft 1, the first male shaft 30 is pushed in until it abuts against the female shaft 10, and the sliding of the first male shaft 30 with respect to the female shaft 10 is restricted. After the first male shaft 30 absorbs the displacement, the second male shaft 40 is pushed into the female shaft 10. That is, the second female spline part 19 and the second male spline part 41 are slid. The impact force applied to the intermediate shaft 1 is absorbed by the energy spent in this sliding motion. Furthermore, as shown in FIG. 9, within the female shaft main body 11 of the female shaft 10, the end of the other axial direction of the first male shaft 30 and the end of the first axial direction of the second male shaft 40 are mutually connected. When it hits, it enters a full collapse state. In this full collapse state, the compressive force applied to the intermediate shaft 1 due to the secondary collision is received by the first male shaft 30 and the second male shaft 40.

Here, the axial length Lc of the gap between the other axial end of the first male shaft 30 and the one axial end of the second male shaft 40 in the nominal state is equal to Equal to or approximately equal to the sum of the protrusion dimension La of the first male spline part 31 from the first female spline part 17 and the protrusion dimension Lb of the second male spline part 41 from the second female spline part 19 of the female shaft 10 (Lc≒La+Lb) (see FIG. 2). Therefore, when the state of full collapse occurs, the other end of the first male shaft 30 in the axial direction and the end of the one end of the second male shaft 40 in the axial direction collide, and an impact force is applied to the intermediate shaft 1. can be received with high strength by the first male shaft 30 and the second male shaft 40. Furthermore, it is desirable that the yoke 3 abuts both ends of the female shaft 10 at the same time, and in that case, the impact force can be received with higher strength.

Next, the retainer 47 provided on the second male shaft 40 will be described in detail.
(A) and (B) of FIG. 10 are explanatory diagrams showing the configuration of the retainer 47 provided on the second male shaft 40, and (A) is a cross-sectional view taken along the line XX shown in (B). B) is an axial cross-sectional view of the female shaft 10 and the second male shaft 40.

As shown in FIGS. 10A and 10B, the retainer 47 fixed to the tip of one axial portion of the second male shaft 40 has a base 51 and a protruding piece 53. The retainer 47 has a base 51 fixed to the tip of the second male shaft 40 by a screw 49. A plurality of protruding pieces 53 (four in this example) are formed, and each protruding piece 53 extends radially outward from the base 51. These protruding pieces 53 are arranged at equal intervals in the circumferential direction when viewed from the front in the axial direction shown in FIG. The outer diameter D of the protruding piece 53 of the retainer 47 is larger than the inner diameter da of the second female spline cylinder portion 15 of the female shaft 10 and smaller than the inner diameter db of the female shaft main body 11 of the female shaft 10. .

(A) and (B) of FIG. 11 are explanatory views for explaining the state in the middle of insertion of the second male shaft into the second female spline cylinder part, and (A) is a cross section taken along the line XI-XI shown in (B). In the figure, (B) is an axial cross-sectional view of the female shaft 10 and the second male shaft 40.
As shown in FIGS. 11A and 11B, when the second male shaft 40 is inserted and attached to the second female spline cylinder portion 15 of the female shaft 10, the protruding piece 53 of the retainer 47 It contacts the inner circumferential surface of the second female spline portion 19 and is elastically deformed. As a result, the second male shaft 40 is inserted into the second female spline cylinder part 15 with the retainer 47 reduced to the same diameter Da as the inner diameter da of the second female spline cylinder part 15 . After that, when the retainer 47 slips out of the second female spline part 19 and crosses the stepped part 21 of the female shaft body 11, the elastically deformed protruding piece 53 returns to its original state, and the retainer 47 moves out of the second female spline part 19. The diameter is expanded to an outer diameter D that is larger than the inner diameter da of the portion 19 (see (A) in FIG. 10). As a result, even if a force is applied to the second male shaft 40 to pull out the second male shaft 40 from the female shaft 10 in the axial direction, the protruding piece 53 of the retainer 47 will not come into contact with the inner peripheral surface of the stepped portion 21. , reinsertion of the retainer 47 into the second female spline portion 19 is prevented. Therefore, the retainer 47 functions to prevent the second male shaft 40 from coming off from the female shaft 10.

Here, the second spline engaging portion 45 has a sliding load ten times or more greater than that of the first spline engaging portion 35, so it slides when a load is applied during normal rotation of the cabin 108 or when traveling. There's nothing to do. However, if a pulling force is applied between the second female spline cylinder part 15 of the female shaft 10 and the second male shaft 40 due to some factor, the second male shaft 40 will come off from the second female spline cylinder part 15. There is a risk. Even in such a case, the second male shaft 40 is provided with a retainer 47 that locks the second female spline portion 19 of the female shaft 10 to prevent it from coming off. It is possible to reliably prevent the second male shaft 40 from coming off from the cylindrical portion 15.

The protruding piece 53 of the retainer 47 may be fixed to the second male shaft 40 not only by the screw 49 but also by a rivet or the like, or the retainer 47 may be formed integrally with the second male shaft 40. Preferably, the retainer 47 has a plurality of protruding pieces 53 evenly arranged in the circumferential direction, and is not limited to the "+"-shaped one having four protruding pieces 53 as illustrated. Further, the retainer 47 is not limited to metal, and may be made of resin or the like.

By the way, the intermediate shaft 1 having the above structure can be mounted in either direction between the steering shaft 102 on the steering wheel 101 side and the steering gear unit 105.

FIG. 12 is a diagram illustrating the operation of the intermediate shaft in each mounting direction, in which (A) is a schematic configuration diagram showing a state in which the first male shaft is directed toward the steering gear unit, and (B) is a diagram illustrating the first male shaft. FIG. 3 is a schematic configuration diagram showing a state in which the shaft is directed toward the steering wheel.

In FIG. 12A, the intermediate shaft 1 is installed with the first male shaft 30 facing toward the steering gear unit 105 side and the second male shaft 40 facing toward the steering wheel 101 side. The first male shaft 30 is connected to the steering gear unit 105, and the second male shaft 40 is connected to the steering shaft 102 of the steering wheel 101.

When the intermediate shaft 1 is mounted in this orientation, the first spline engagement portion 35, which is the engagement portion between the first female spline portion 17 and the first male spline portion 31 that slide under a small load, is connected to the steering gear unit 105. placed on the side. According to this, it is possible to suppress transmission of vibrations and shocks during driving to the steering wheel 101 operated by the driver, and drivability can be improved.

In FIG. 12B, the intermediate shaft 1 is installed so that the first male shaft 30 is directed toward the steering wheel 101 side, and the second male shaft 40 is directed toward the steering gear unit 105 side. The first male shaft 30 is connected to the steering shaft 102 of the steering wheel 101, and the second male shaft 40 is connected to the steering gear unit 105.

When the intermediate shaft 1 is mounted in this orientation, the first spline engagement portion 35, which is the engagement portion between the first female spline portion 17 and the first male spline portion 31 that slide with a small load, is located on the steering wheel 101 side. It is located in Thereby, the operating force required when adjusting the height of the steering wheel 101 by performing a tilt operation can be reduced, and the driver can perform the tilt operation favorably.

Next, the wobbling that occurs in the intermediate shaft 1 of this configuration will be explained.
FIG. 13 is a schematic diagram illustrating the wobbling that occurs in the intermediate shaft.

In an intermediate shaft having a slidable portion in the intermediate portion, whirling may occur at the sliding portion when an external force is applied.

P1 and P2 shown in FIG. 13 are fixed points corresponding to the yoke 3 of the intermediate shaft 1, and S1 is a shaft connecting part that can slide with the lightest load, corresponding to the first spline engagement part 35 of the intermediate shaft 1. It is. The swing of the intermediate shaft MS1, which is equivalent to the present configuration in which the shaft connecting portion (first spline engaging portion 35) is located near one end in the axial direction, is shown by a solid line. Further, as a reference example, the swinging state of the intermediate shaft MS2, which has a shaft connecting portion at the center in the axial direction, is shown by a dotted line.

With the intermediate shaft MS1 that can slide near one end in the axial direction, even if run-out occurs at the slide point S1 and the inclination angle θ occurs with respect to the axis, the length from the end to the slide point S1 The length L1 can be shortened. If the length L1 is small, the bending moment acting on the sliding portion S1 will also be small. Therefore, in this intermediate shaft MS1, the influence of the bending moment is suppressed, the swing width δ1 at the sliding portion 1 does not increase, and the swing is suppressed.

On the other hand, in the intermediate shaft MS2, which is capable of sliding near the center in the axial direction, if run-out occurs at the sliding location S2 and the same inclination angle θ as in the case of the intermediate shaft MS1 occurs, the end portion The length L2 to the slide point S2 is larger than the above-mentioned length L1. In this case, the bending moment acting on the sliding portion S2 becomes larger than that on the intermediate shaft MS1. Therefore, in this intermediate shaft MS2, due to the influence of the bending moment, the swing width δ2 at the sliding portion S2 becomes larger than that of the intermediate shaft MS1, resulting in a large swing.

The intermediate shaft 1 according to the present embodiment includes a first male shaft 30 and a second male shaft 40 at both ends of the female shaft 10, and the sliding portion of the female shaft 10 and the first male shaft 30 is within the entire length of the intermediate shaft 1. It will be placed closer to one end (see Figure 2). Therefore, in the intermediate shaft 1, similarly to the above-mentioned intermediate shaft MS1, the influence of the bending moment acting on the sliding portion can be suppressed to reduce the swing width, and the occurrence of run-out can be suppressed. Furthermore, according to the intermediate shaft 1 of this configuration, the influence of bending moment at the sliding part is suppressed, so a stable sliding load can be obtained, and it has excellent characteristics against stick-slip vibration and abnormal noise. This becomes the intermediate axis.

Here, the sliding portion S1, for example, the axial center position of the first female spline portion 17 of the female shaft 10, is from the end of the intermediate shaft 1 on the first male shaft 30 side, when the entire length of the intermediate shaft 1 is L. It is preferable to arrange it in a range up to L/3 or less toward the axial center position (L/2). More preferably, it is arranged in a range up to L/4, and still more preferably in a range up to L/5.

As described above, according to the intermediate shaft 1 of this configuration, the first female spline portion 17 formed on the inner peripheral surface of one end side of the female shaft 10 and the outer peripheral surface of the first male shaft 30 The first male spline part 31 engages with a spline, and the second female spline part 19 is formed on the inner peripheral surface of the other end of the female shaft 10 and the second male spline part 19 is formed on the outer peripheral surface of the second male shaft 40. The spline portion 41 is in spline engagement. The female shaft 10 has a structure in which the first female spline cylinder part 13 in which the first female spline part 17 is formed in advance is welded and integrated with the female shaft main body 11, so splines are attached to both ends of one pipe body. The first female spline part 17 and the second female spline part 19 can be manufactured with high precision compared to the case where they are formed. In this way, although the intermediate shaft 1 has a structure in which the outer peripheral surfaces of the first male shaft 30 and the second male shaft 40 are engaged with the inner peripheral surfaces of both ends of the female shaft 10, it is possible to reduce manufacturing costs while , the accuracy of the spline section can be improved.

Further, the sliding portion where the first female spline portion 17 and the first male spline portion 31 of the female shaft 10 have a low sliding load can be placed closer to one end in the axial direction, thereby suppressing the run-out that occurs at the sliding portion. be able to. In addition, the influence of bending moment at the sliding location is suppressed, resulting in a stable sliding load, making it difficult for stick-slip vibrations and abnormal noises to occur.

In the above configuration, the first female spline part 17 and the second female spline part 19 of the female shaft 10 are arranged in the same phase in the circumferential direction. ), (C), the yoke 3 of the first male shaft 30 and the yoke 3 of the second male shaft 40 may be arranged in different phases by an angle φ about the axis. In that case, in addition to shifting the first female spline part 17 and the second female spline part 19 by an arbitrary pitch in the circumferential direction and engaging them with the female shaft 10, the first female spline part 17 of the female shaft 10 The teeth of the second female spline portion 19 and the teeth of the second female spline portion 19 may be shifted from each other in the circumferential direction. Thereby, the phase can be adjusted to a finer angle than the pitch width.

Further, in the above embodiment, a case is illustrated in which the first male shaft 30 and the second male shaft 40 are solid, but both or one of the first male shaft 30 and the second male shaft 40 is It may be formed into a hollow cylindrical shape.

As described above, the present invention is not limited to the embodiments described above, and those skilled in the art can combine the configurations of the embodiments with each other, modify and apply them based on the description of the specification and well-known techniques. It is also contemplated by the present invention to do so, and is within the scope for which protection is sought.

As mentioned above, the following matters are disclosed in this specification.
(1) It has a cylindrical shape with open ends on both sides in the axial direction, and has a first female spline part on the inner peripheral surface of one axial part, and a second female spline part on the inner peripheral surface of the other axial part. a female shaft having a
a first male shaft having a first male spline portion on the outer peripheral surface of the other axial portion;
a second male shaft having a second male spline portion on the outer circumferential surface of one portion in the axial direction;
Equipped with
the first male spline portion of the first male shaft is spline engaged with the first female spline portion of the female shaft;
the second male spline portion of the second male shaft is press-fitted into spline engagement with the second female spline portion of the female shaft;
An intermediate shaft for a steering device, wherein a sliding load of the first male shaft with respect to the female shaft is smaller than a sliding load of the second male shaft with respect to the female shaft.
According to this intermediate shaft for a steering device, the first female spline portion formed on the inner circumferential surface of one end side of the female shaft and the first male spline portion formed on the outer circumferential surface of the first male shaft engage in spline engagement. However, a second female spline portion formed on the inner circumferential surface of the other end of the female shaft and a second male spline portion formed on the outer circumferential surface of the second male shaft are in spline engagement. In this way, this intermediate shaft has a structure in which the inner circumferential surface at both ends of the female shaft and the outer circumferential surfaces of the first male shaft and the second male shaft fit together, which reduces the bulk of manufacturing costs. At the same time, it is possible to improve the accuracy of connecting portions such as splines.
Further, the sliding portion of the first female spline portion and the first male spline portion of the female shaft can be arranged closer to one end, and swinging that occurs at the sliding portion can be suppressed. Furthermore, since the influence of bending moment at the sliding portion is suppressed, a stable sliding load can be obtained, and excellent characteristics can be provided against vibration and abnormal noise caused by stick-slip.

(2) The intermediate shaft for a steering device according to (1), wherein the second male shaft is a shock absorbing shaft having a sliding load that is 10 times or more greater than the sliding load of the first male shaft.
According to this intermediate shaft for a steering device, after the first male shaft slides with respect to the female shaft, the second male shaft slides with respect to the female shaft, so that the impact applied to the intermediate shaft is effectively absorbed by the second male shaft. It can be absorbed.

(3) further comprising: a first coating layer made of synthetic resin that covers the first male spline portion; and a second coating layer made of synthetic resin that covers the second male spline portion;
The first female spline portion and the first male spline portion are in spline engagement via the first coating layer,
The intermediate shaft for a steering device according to (1) or (2), wherein the second female spline portion and the second male spline portion are spline engaged with each other via the second coating layer.
According to this intermediate shaft for a steering device, the first male spline portion and the second male spline portion are protected by providing the first coating layer and the second coating layer on the first male spline portion and the second male spline portion. Moreover, the durability of the female shaft when sliding on the first female spline portion and the second female spline portion can be improved.

(4) A first spline engagement portion between the first female spline portion and the first male spline portion, and a second spline engagement portion between the second female spline portion and the second male spline portion, respectively. The intermediate shaft for a steering device according to any one of (1) to (3), wherein the intermediate shaft is lubricated with grease.
According to this intermediate shaft for a steering device, by lubricating the first spline engaging portion and the second spline engaging portion with grease, it is possible to protect these engaging portions, and moreover, it is possible to protect the engaging portions by lubricating the first spline engaging portion and the second spline engaging portion with grease. It can be slid smoothly.

(5) The axial length between the end of the other axial part of the first male shaft and the end of the one axial part of the second male shaft is the length of the first male shaft from the first female spline part. For the steering device according to any one of (1) to (4), the steering device is equal to the sum of the protrusion dimension of the first male spline portion and the protrusion dimension of the second male spline portion from the second female spline portion. intermediate axis.
According to this intermediate shaft for a steering device, when an impact force is applied to the intermediate shaft and a full collapse state occurs, the end of the other axial part of the first male shaft and the end of one axial part of the second male shaft The department collides. Thereby, the impact force applied to the intermediate shaft can be well received by the first male shaft and the second male shaft.

(6) The female shaft includes a stepped portion that has a larger diameter than the inner diameter of the second female spline portion, located closer to the second female spline portion between the first female spline portion and the second female spline portion. has
The second male shaft has an elastically deformable retainer at the tip of one axial portion,
The retainer is inserted into the second female spline part with its diameter reduced due to elastic deformation, and when it comes out of the second female spline part, the stopper has a diameter larger than the inner diameter of the second female spline part at the stepped part. The intermediate shaft for a steering device according to any one of (1) to (5), which elastically returns to prevent reinsertion into the second female spline portion.
According to this intermediate shaft for a steering device, even if a pull-out force with respect to the female shaft is applied to the second male shaft, the retainer locks the end of the second female spline portion. Therefore, reinsertion into the second female spline portion is prevented, and the second male shaft can be effectively prevented from coming off from the female shaft.

(7) The retainer is
a base fixed to the tip of the second male shaft;
a plurality of protruding pieces extending radially outward from the base and inclined rearward in the direction of insertion into the second female spline part;
The intermediate shaft for a steering device according to (6), comprising:
According to this intermediate shaft for a steering device, the plurality of protruding pieces extending radially outward from the base and tilted toward the rear in the direction of insertion into the second female spline portion lock the stepped portion, so that the female The second male shaft can be effectively prevented from coming off from the shaft.

(8) The intermediate for a steering device according to any one of (1) to (7), wherein the first female spline part and the second female spline part are arranged in the same phase in the circumferential direction. shaft.
According to this intermediate shaft for a steering device, the first male shaft and the second male shaft can be connected to the joint of the steering device in the same phase.

(9) The intermediate for a steering device according to any one of (1) to (8), wherein the first female spline part and the second female spline part are arranged in different phases in the circumferential direction. shaft.
According to this intermediate shaft for a steering device, the first female spline portion and the second female spline portion connect the first male shaft and the second male shaft, which are arranged in different phases in the circumferential direction, to the joint of the steering device. This increases the degree of freedom in arranging the intermediate shaft in the steering device, thereby increasing versatility.

(10) Steering gear unit;
steering wheel and
The intermediate shaft for a steering device according to any one of (1) to (9), which is provided between the steering gear unit and the steering wheel;
A steering device comprising:
According to this steering device, it is possible to suppress an increase in cost, and to suppress swinging due to bending of the intermediate shaft even when external force is applied, thereby suppressing the generation of vibration and abnormal noise.

(11) The first male shaft is connected to a steering gear unit,
The intermediate shaft for a steering device according to (10), wherein the second male shaft is connected to a steering wheel side.
According to this steering device, the engagement portion between the first female spline portion and the first male spline portion that slide with a small load is provided on the steering gear unit side. Thereby, it is possible to suppress the transmission of vibrations and shocks during driving to the steering wheel operated by the driver, and it is possible to improve drivability.

(12) the first male shaft is connected to a steering wheel;
The intermediate shaft for a steering device according to (10), wherein the second male shaft is connected to a steering gear unit side.
According to this steering device, the engagement portion between the first female spline portion and the first male spline portion that slide with a small load is provided on the steering wheel side. Thereby, it is possible to reduce the operating force when adjusting the height of the steering wheel by performing a tilt operation, and it is possible to allow the driver to perform the tilt operation favorably.

1 Intermediate shaft (intermediate shaft for steering device)
3 Yoke 10 Female shaft 17 First female spline portion 19 Second female spline portion 21 Stepped portion 30 First male shaft 31 First male spline portion 35 First spline engaging portion 40 Second male shaft 41 Second male spline portion 45 Second spline engagement part (press-fit spline engagement part)
47 Retainer 51 Base 53 Projecting piece 101 Steering wheel 105 Steering gear unit

Claims (12)

The female is configured in a cylindrical shape with open ends on both sides in the axial direction, and has a first female spline portion on the inner circumferential surface of one axial portion, and a second female spline portion on the inner circumferential surface of the other axial portion. axis and
a first male shaft assembled to one axial portion of the female shaft and having a first male spline portion on an outer peripheral surface;
a second male shaft assembled to the other axial portion of the female shaft and having a second male spline portion on the outer peripheral surface;
Equipped with
the first male spline portion of the first male shaft is spline engaged with the first female spline portion of the female shaft;
the second male spline portion of the second male shaft is press-fitted into spline engagement with the second female spline portion of the female shaft;
A sliding load of the first male shaft with respect to the female shaft is smaller than a sliding load of the second male shaft with respect to the female shaft,
After the first male shaft fully enters the female shaft due to the impact force caused by the collision, the end of the second male shaft abuts the end of the first male shaft within the female shaft.
Intermediate shaft for steering device. The female is configured in a cylindrical shape with open ends on both sides in the axial direction, and has a first female spline portion on the inner circumferential surface of one axial portion, and a second female spline portion on the inner circumferential surface of the other axial portion. axis and
a first male shaft assembled to one axial portion of the female shaft and having a first male spline portion on an outer peripheral surface;
a second male shaft assembled to the other axial portion of the female shaft and having a second male spline portion on the outer peripheral surface;
Equipped with
the first male spline portion of the first male shaft is spline engaged with the first female spline portion of the female shaft;
the second male spline portion of the second male shaft is press-fitted into spline engagement with the second female spline portion of the female shaft;
A sliding load of the first male shaft with respect to the female shaft is smaller than a sliding load of the second male shaft with respect to the female shaft,
The axial length between the end of the first male shaft and the end of the second male shaft in the female shaft is the length of the first male shaft from the end of the first female spline part in the axial direction. always equal to the sum of the protrusion dimension of the first male spline part and the protrusion dimension of the second male spline part from the other end of the second female spline part in the axial direction ;
Intermediate shaft for steering device. The female is configured in a cylindrical shape with open ends on both sides in the axial direction, and has a first female spline portion on the inner circumferential surface of one axial portion, and a second female spline portion on the inner circumferential surface of the other axial portion. axis and
a first male shaft assembled to one axial portion of the female shaft and having a first male spline portion on an outer peripheral surface;
a second male shaft assembled to the other axial portion of the female shaft and having a second male spline portion on the outer peripheral surface;
Equipped with
the first male spline portion of the first male shaft is spline engaged with the first female spline portion of the female shaft;
the second male spline portion of the second male shaft is press-fitted into spline engagement with the second female spline portion of the female shaft;
A sliding load of the first male shaft with respect to the female shaft is smaller than a sliding load of the second male shaft with respect to the female shaft,
The female shaft has a stepped portion located closer to the second female spline portion between the first female spline portion and the second female spline portion, the stepped portion having a diameter larger than the inner diameter of the second female spline portion. ,
The second male shaft has an elastically deformable retainer at the tip of one axial portion,
The retainer is inserted into the second female spline part with its diameter reduced due to elastic deformation, and when it comes out of the second female spline part, the stopper has a diameter larger than the inner diameter of the second female spline part at the stepped part. elastically returning to prevent reinsertion into the second female spline portion;
Intermediate shaft for steering device. The retainer is
a base fixed to the tip of the second male shaft;
a plurality of protruding pieces extending radially outward from the base and inclined rearward in the direction of insertion into the second female spline part;
Equipped with
The intermediate shaft for a steering device according to claim 3. The female is configured in a cylindrical shape with open ends on both sides in the axial direction, and has a first female spline portion on the inner circumferential surface of one axial portion, and a second female spline portion on the inner circumferential surface of the other axial portion. axis and
a first male shaft assembled to one axial portion of the female shaft and having a first male spline portion on an outer peripheral surface;
a second male shaft assembled to the other axial portion of the female shaft and having a second male spline portion on the outer peripheral surface;
Equipped with
the first male spline portion of the first male shaft is spline engaged with the first female spline portion of the female shaft;
the second male spline portion of the second male shaft is press-fitted into spline engagement with the second female spline portion of the female shaft;
A sliding load of the first male shaft with respect to the female shaft is smaller than a sliding load of the second male shaft with respect to the female shaft,
the first female spline portion and the second female spline portion are arranged in the same phase in the circumferential direction;
Intermediate shaft for steering device. The female is configured in a cylindrical shape with open ends on both sides in the axial direction, and has a first female spline portion on the inner circumferential surface of one axial portion, and a second female spline portion on the inner circumferential surface of the other axial portion. axis and
a first male shaft assembled to one axial portion of the female shaft and having a first male spline portion on an outer peripheral surface;
a second male shaft assembled to the other axial portion of the female shaft and having a second male spline portion on the outer peripheral surface;
Equipped with
the first male spline portion of the first male shaft is spline engaged with the first female spline portion of the female shaft;
the second male spline portion of the second male shaft is press-fitted into spline engagement with the second female spline portion of the female shaft;
A sliding load of the first male shaft with respect to the female shaft is smaller than a sliding load of the second male shaft with respect to the female shaft,
the first female spline portion and the second female spline portion are arranged at different phases in the circumferential direction;
Intermediate shaft for steering device. The second male shaft is a shock absorbing shaft having a sliding load that is 10 times or more greater than the sliding load of the first male shaft.
The intermediate shaft for a steering device according to any one of claims 1 to 6. further comprising a first coating layer made of synthetic resin that covers the first male spline portion, and a second coating layer made of synthetic resin that covers the second male spline portion,
The first female spline portion and the first male spline portion are in spline engagement via the first coating layer,
The second female spline portion and the second male spline portion are in spline engagement via the second coating layer.
The intermediate shaft for a steering device according to any one of claims 1 to 7. A first spline engagement portion between the first female spline portion and the first male spline portion, and a second spline engagement portion between the second female spline portion and the second male spline portion are each coated with grease. is lubricated by
The intermediate shaft for a steering device according to any one of claims 1 to 8. steering gear unit,
steering wheel and
The intermediate shaft for a steering device according to any one of claims 1 to 9, which is provided between the steering gear unit and the steering wheel;
A steering device comprising: The first male shaft is connected to a steering gear unit,
The second male shaft is connected to a steering wheel side.
The steering device according to claim 10. the first male shaft is connected to a steering wheel;
the second male shaft is connected to a steering gear unit;
The steering device according to claim 10.

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