JP2021076124A - Intermediate shaft and method for manufacturing the same - Google Patents

Abstract

To realize a structure of an intermediate shaft that easily secures an extension/contraction stroke, and can reduce manufacturing cost.SOLUTION: An intermediate shaft 1 comprises a female shaft 2, a first male shaft 3a, a second male shaft 3b, and yokes 19a and 19b. The female shaft 2 is constituted in a cylindrical shape in which end parts on both sides in an axial direction are opened, comprises a first female spline part 6a in one side part in the axial direction of an inner peripheral surface, and comprises a second female spline part 6b in the other side part in the axial direction of the inner peripheral surface. The first male shaft 3a comprises a first male spline part 10a spline-engaged with the first female spline part 6a, in an outer peripheral surface of the other side part in the axial direction. The second male shaft 3b comprises a second male spline part 10b spline-engaged with the second female spline part 6b, in an outer peripheral surface of one side part in the axial direction. The yokes 19a and 19b are fixed to an end part on one side in the axial direction of the first male shaft 3a and an end part on the other side in the axial direction of the second male shaft 3b. The first male shaft 3a and the second male shaft 3b have the same specifications.SELECTED DRAWING: Figure 1

Description

The present invention relates to an intermediate shaft constituting an automobile steering device and a method for manufacturing the intermediate shaft.

In a steering device for a large truck, which is a large vehicle, for example, as shown in FIG. 24, the movement of the steering wheel 101 operated by the driver is controlled by a plurality of shafts such as the steering shaft 102 and the intermediate shaft 103, and these shafts. It is configured to be transmitted to the steering gear unit 105 via the universal joints 104a and 104b in which the ends of the 102 and 103 are connected to each other.

The intermediate shaft 103 has a structure that can be expanded and contracted in the axial direction. For this reason, in the illustrated example, the intermediate shaft 103 is configured by combining the female shaft 106 and the male shaft 107 so that torque can be transmitted and relative movement in the axial direction is possible. More specifically, the intermediate shaft 103 is configured by spline-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. Has been done.

The heavy-duty truck includes a tilt shaft 109 that rotatably supports the front end of the cabin (driver's cab) 108 with respect to a chassis frame (not shown). As shown by the solid line → chain line in FIG. 24, the heavy-duty truck is in a cab lt state in which the engine portion is exposed to the outside by rotating the cabin 108 so as to tilt forward around the tilt axis 109. It is possible to achieve it. When the intermediate shaft 103 realizes such a cab lt state, the female shaft 106 and the male shaft 107 move relative to each other in the axial direction to extend the total length, so that the distance between the steering shaft 102 and the steering gear unit 105 is increased. Allow to spread. As described above, in a large truck, it is necessary to greatly extend the total length of the intermediate shaft 103 in order to realize the cabtilt state, so that it is necessary to secure a large expansion / contraction stroke of the intermediate shaft 103.

However, in the intermediate shaft 103 formed by combining two dividing shafts (female shaft 106 and male shaft 107) as shown in the figure, in order to secure a large expansion / contraction stroke, the axial dimensions of the two dividing shafts are respectively. Needs to be large. As a result, in particular, with respect to the male shaft 107, molding by highly productive press working becomes difficult, bending due to lengthening tends to occur, and a process for correcting the bending becomes necessary, and the manufacturing cost is increased. It tends to be disadvantageous in terms of suppressing.

On the other hand, Japanese Patent Application Laid-Open No. 2003-146225 (Patent Document 1) describes an intermediate shaft formed by combining three dividing shafts. This intermediate shaft has a tubular large-diameter shaft, a tubular medium-diameter shaft in which the outer peripheral surface is spline-engaged with the inner peripheral surface of the large-diameter shaft, and a spline engagement with the outer peripheral surface on the inner peripheral surface of the medium-diameter shaft. It is equipped with a combined small diameter shaft.

An intermediate shaft formed by combining three such divided shafts (large diameter shaft, medium diameter shaft, and small diameter shaft) is compared with an intermediate shaft formed by combining two divided shafts (female shaft, male shaft). Even when the expansion and contraction strokes of the same size are secured, the axial dimensions of each division shaft can be kept small, so that each division shaft can be easily molded by a highly productive processing method, which is advantageous in terms of reducing the manufacturing cost. It becomes.

Japanese Unexamined Patent Publication No. 2003-146225

However, in the intermediate shaft described in Japanese Patent Application Laid-Open No. 2003-146225, it is necessary to form spline portions on each of the outer peripheral surface and the inner peripheral surface of the medium diameter shaft. Therefore, regardless of which of the peripheral surfaces of the spline portion is formed first, the spline portion formed earlier is likely to be distorted due to the processing of the spline portion formed later. Therefore, the manufacturing cost tends to increase due to the need for additional machining to correct the distortion generated in this way. Further, since the three divided shafts (large diameter shaft, medium diameter shaft, and small diameter shaft) are parts having different shapes and sizes, the manufacturing cost tends to increase in this respect as well.

In view of the above circumstances, it is an object of the present invention to realize a structure of an intermediate shaft in which it is easy to secure an expansion / contraction stroke and the manufacturing cost can be suppressed.

The intermediate shaft of the present invention includes a female shaft, a first male shaft, a second male shaft, a first yoke forming a first universal joint, and a second yoke forming a second universal joint.
The female shaft is formed in a tubular shape with both ends in the axial direction open, has a first female spline portion on one side in the axial direction of the inner peripheral surface, and has the other side in the axial direction of the inner peripheral surface. Has a second female spline portion.
The first male shaft has a first male spline portion that is spline-engaged with the first female spline portion on the outer peripheral surface of the other side portion in the axial direction.
The second male shaft has a second male spline portion that is spline-engaged with the second female spline portion on the outer peripheral surface of one side portion in the axial direction.
The first yoke is fixed to one end of the first male shaft on one side in the axial direction.
The second yoke is fixed to the other end of the second male axis in the axial direction.
The first male shaft and the second male shaft have the same specifications.
In one aspect of the intermediate shaft of the present invention, the same specifications have the same shape and dimensions.

In one aspect of the intermediate shaft of the present invention, a first coating layer made of synthetic resin covering the first male spline portion and a second coating layer made of synthetic resin covering the second male spline portion are further provided. The first female spline portion and the first male spline portion are spline-engaged via the first coating layer, and the second female spline portion and the second male spline portion form the second coating layer. Spline engaged through.

In one aspect of the intermediate shaft of the present invention, a spline engaging portion between the first female spline portion and the first male spline portion, and a spline engaging portion between the second female spline portion and the second male spline portion. Each of and is lubricated with grease.

In one aspect of the intermediate shaft of the present invention, the sliding load of the first male shaft with respect to the female shaft and the sliding load of the second male shaft with respect to the female shaft are different from each other.

In one aspect of the intermediate shaft of the present invention, each of the first male shaft and the second male shaft is formed in a tubular shape with both ends in the axial direction open.
In this case, in one aspect of the intermediate shaft of the present invention, either the axial one-sided end opening of the first male shaft or the axially opposite end opening of the second male shaft. Only one end opening is closed by the closing member.

In one aspect of the intermediate shaft of the present invention, the female shaft is formed on an inner peripheral surface that is adjacent to one side of the first female spline portion in the axial direction and the other side of the second female spline portion in the axial direction. In at least one of the adjacent portions, the first male shaft or the second male shaft existing inside the portion in the radial direction moves to the end in the direction of increasing the axial dimension of the intermediate shaft. In this case, the first male shaft or the second male shaft has an outer escape recess that is radially opposed to only a part of the first male spline portion or the second male spline portion in the axial direction through a gap. ..

In one aspect of the intermediate shaft of the present invention, the female shaft is located in a portion of the inner peripheral surface sandwiched between the first female spline portion and the second female spline portion in the axial direction. When each of the male shaft and the second male shaft moves to the end portion in the direction of reducing the axial dimension of the intermediate shaft, the respective shafts of the first male spline portion and the second male spline portion. It has an inner relief recess that faces only a part of the direction and in the radial direction through a gap.

In one aspect of the intermediate shaft of the present invention, the female shaft is formed in a portion of the inner peripheral surface sandwiched between the first female spline portion and the second female spline portion in the axial direction. When each of the male shaft and the second male shaft moves to the end portion in the direction of reducing the axial dimension of the intermediate shaft, either the first male spline portion or the second male spline portion is used. It has an inner relief recess that opposes in the radial direction through a gap with only a part of the male spline portion in the axial direction.

In one aspect of the intermediate shaft of the present invention, the first female spline portion and the second female spline portion are arranged in the same phase with respect to the circumferential direction and are formed continuously in the axial direction.

In one aspect of the intermediate shaft of the present invention, the first female spline portion and the second female spline portion are arranged in different phases with respect to the circumferential direction.

The method for manufacturing an intermediate shaft of the present invention is a spline engaging portion between the first female spline portion and the first male spline portion, and a spline engaging portion between the second female spline portion and the second male spline portion. It is provided with a heating familiarization process that is individually performed for each of the above.
In the heating familiarization step, the female spline portion and the male spline portion are reciprocally slid while heating the female spline portion in a state where the female spline portion and the male spline portion are spline-engaged via the coating layer. By moving, the surface layer portion of the coating layer is heated to a temperature equal to or higher than the melting point of the coating layer and melted, so that the surface of the coating layer is adapted to the surface of the female spline portion, and then the coating is applied. This is a step of cooling the layer and the female shaft.

In one aspect of the method for manufacturing an intermediate shaft of the present invention, a spline engaging portion between the first female spline portion and the first male spline portion, and a spline between the second female spline portion and the second male spline portion. By making the heating conditions of the female spline portion different from those of the engaging portion, the sliding load of the first male shaft with respect to the female shaft and the sliding of the second male shaft with respect to the female shaft are different. Make the dynamic load different from each other.

According to the intermediate shaft of the present invention, it is easy to secure the expansion / contraction stroke, and the manufacturing cost can be suppressed.

FIG. 1 is a partially cut side view showing the intermediate shaft of the first example of the embodiment in a state where each of the pair of male shafts is located in the axial middle portion of the movable range with respect to the female shaft. 2A is a sectional view taken along the line AA of FIG. 1, FIG. 2B is a sectional view taken along the line BB of FIG. 1, and FIG. 2C is a sectional view taken along the line CC of FIG. It is a figure. FIG. 3A is a cross-sectional view of the axial one-side (right side) end of FIG. 1, and FIG. 3B is a cross-sectional view of the axial other-side (left) end of FIG. FIG. 4 is a cross-sectional view showing only the female shaft taken out from FIG. FIG. 5 shows that with respect to the intermediate shaft of the first example of the embodiment, the male axis on one side in the axial direction has moved from the state shown in FIG. 1 to the end on one side in the axial direction in the movable range with respect to the female axis. It is a figure which shows the state. FIG. 6 is an enlarged view of part D of FIG. In FIG. 7, with respect to the intermediate shaft of the first example of the embodiment, the male axis on the other side in the axial direction has moved from the state shown in FIG. 5 to the end on the other side in the axial direction in the movable range with respect to the female axis. It is a figure which shows the state. FIG. 8 shows that with respect to the intermediate shaft of the first example of the embodiment, the male axis on one side in the axial direction has moved from the state shown in FIG. 7 to the end on the other side in the axial direction in the movable range with respect to the female axis. It is a figure which shows the state. In FIG. 9, with respect to the intermediate shaft of the first example of the embodiment, from the state shown in FIG. 8, the male axis on the other side in the axial direction has moved to the end on one side in the axial direction in the movable range with respect to the female axis. It is a figure which shows the state. FIG. 10 is a diagram corresponding to FIG. 3 (b) showing a modified example of the first example of the embodiment. FIG. 11 is a diagram corresponding to FIG. 1 with respect to the intermediate shaft of the second example of the embodiment. FIG. 12 is a cross-sectional view taken along the line EE of FIG. FIG. 13 is a cross-sectional view showing only the female shaft taken out from FIG. FIG. 14 is a diagram corresponding to FIG. 9 regarding the intermediate shaft of the second example of the embodiment. FIG. 15 is a diagram corresponding to FIG. 7 with respect to the intermediate shaft of the second example of the embodiment. FIG. 16 is an enlarged view of the F portion of FIG. FIG. 17 is a diagram corresponding to FIG. 1 with respect to the intermediate shaft of the third example of the embodiment. FIG. 18 is a diagram corresponding to FIG. 9 with respect to the intermediate shaft of the third example of the embodiment. FIG. 19 is a diagram corresponding to FIG. 8 with respect to the intermediate shaft of the fourth example of the embodiment. FIG. 20 is a diagram corresponding to FIG. 9 with respect to the intermediate shaft of the fourth example of the embodiment. FIG. 21 shows a state in which the male axis on the other side in the axial direction has moved from the state shown in FIG. 20 to the axial intermediate portion of the movable range with respect to the female axis with respect to the intermediate shaft of the fourth example of the embodiment. It is a figure. FIG. 22 is a diagram corresponding to FIG. 5 regarding the intermediate shaft of the fourth example of the embodiment. FIG. 23 is a diagram corresponding to FIG. 7 regarding the intermediate shaft of the fourth example of the embodiment. FIG. 24 is a partially cut side view showing an example of a conventionally known steering device for a large truck.

[First Example of Embodiment]
A first example of the embodiment of the present invention will be described with reference to FIGS. 1 to 9.

The intermediate shaft 1 of this example is a rotating shaft that is incorporated in a steering device of a large truck and transmits the movement of the steering shaft 102 to the steering gear unit 105 (see FIG. 24). In the following description, with respect to the intermediate shaft 1, one side in the axial direction is on the right side in FIGS. 1 to 3 and 5-9, and the other side in the axial direction is on the left side in FIGS. In a state where the steering device including the intermediate shaft 1 of this example is mounted on the vehicle, the intermediate shaft 1 is inserted into a through hole formed in a panel that separates the inside of the vehicle from the outside of the vehicle. One side portion in the axial direction is arranged inside the vehicle interior, and the other side portion in the axial direction is arranged outside the vehicle interior.

The intermediate shaft 1 includes a female shaft 2, a first male shaft 3a, a second male shaft 3b, a first coating layer 4a, a second coating layer 4b, a pair of retaining members 5, and a closing member 18. And a pair of yokes 19a and 19b.

The female shaft 2 is formed in a cylindrical shape with both ends in the axial direction open, and has a female spline portion 6 on the inner peripheral surface over almost the entire length in the axial direction. The entire length of the female spline portion 6 is formed in a continuous manner by broaching. In FIGS. 1, 4, 5, 7, 8 and 9, the chain line Cp indicates the axial center position of the female axis 2. In this example, the portion of the female spline portion 6 located on one side of the chain line Cp in the axial direction is referred to as the first female spline portion 6a, and the portion of the female spline portion 6 located on the other side of the chain line Cp in the axial direction. Is the second female spline portion 6b. That is, in this example, the first female spline portion 6a and the second female spline portion 6b are arranged in the same phase with respect to the circumferential direction and are formed continuously in the axial direction.

Each of the first male shaft 3a and the second male shaft 3b is an end portion on the axial base end side (the side closer to the axial center position (chain line Cp) of the female shaft 2 in the state where the intermediate shaft 1 is assembled). It has a male spline portion (first male spline portion 10a, second male spline portion 10b) on the outer peripheral surface. In this example, the first male shaft 3a and the second male shaft 3b have the same specifications, in other words, have the same shape and dimensions. In this example, the first male axis 3a and the second male axis 3b use different symbols, but the shapes and dimensions of the respective parts are the same for the first male axis 3a and the second male axis 3b. It is the same.

Each of the first male shaft 3a and the second male shaft 3b is formed in a cylindrical shape in which the ends on both sides in the axial direction are open, and the large-diameter tubular portions 7a and 7b are arranged in order from the axial base end side. , The small diameter cylinder portions 8a and 8b, and the fitting cylinder portions 9a and 9b (see FIGS. 3A and 3B).

The large-diameter tubular portions 7a and 7b have male spline portions (first male spline portion 10a, second male spline portion 10b) on the outer peripheral surface. The small diameter tubular portions 8a and 8b are cylindrical portions having an outer diameter smaller than the diameter of the root circle of the male spline portions (first male spline portion 10a and second male spline portion 10b). The end of the outer peripheral surfaces of the large-diameter tubular portions 7a and 7b (the side far from the axial center position (chain line Cp) of the female shaft 2 in the state where the intermediate shaft 1 is assembled) and the small-diameter tubular portion 8a. , 8b is connected to the end portion of the outer peripheral surface on the axial direction base end side by tapered surface-shaped stepped surfaces 11a and 11b facing the tip end side in the axial direction. The fitting cylinder portions 9a and 9b are cylindrical portions having an outer diameter smaller than the outer diameter of the small diameter cylinder portions 8a and 8b. The ends of the outer peripheral surfaces of the small-diameter cylinders 8a and 8b on the distal end side in the axial direction and the ends of the outer peripheral surfaces of the fitting cylinders 9a and 9b on the axial base end side are circles facing the distal end in the axial direction. It is connected by ring-shaped stepped surfaces 12a and 12b. Of the male shaft 3, the axial dimensions of the remaining portion (the portion corresponding to the large diameter cylinders 7a and 7b and the small diameter cylinders 8a and 8b) excluding the fitting cylinders 9a and 9b are the axial dimensions of the female shaft 2. It is less than half the size. The surface of the male spline portion (first male spline portion 10a, second male spline portion 10b) is covered with a coating layer (first coating layer 4a, second coating layer 4b) made of a synthetic resin such as a polyamide resin. ..

As shown in FIG. 1, the first male spline portion 10a is attached to the first female spline portion 6a of the female shaft 2 in a state where the tip portion in the axial direction is directed to one side in the axial direction. 1 Spline is engaged via the coating layer 4a. As a result, the first male shaft 3a and the female shaft 2 are combined so that torque can be transmitted and relative movement in the axial direction is possible. The spline engaging portion (via the first coating layer 4a) between the first male spline portion 10a and the first female spline portion 6a is lubricated with grease.

As shown in FIG. 1, the second male spline portion 10b is coated on the second female spline portion 6b of the female shaft 2 with the second male spline portion 10b in a state where the tip portion thereof is directed to the other side in the axial direction. Splines are engaged via layer 4b. As a result, the second male shaft 3b and the female shaft 2 are combined so that torque can be transmitted and relative movement in the axial direction is possible. The spline engaging portion (via the second coating layer 4b) between the second male spline portion 10b and the second female spline portion 6b is lubricated with grease.

In this example, the sliding load of the first male shaft 3a with respect to the female shaft 2 (sliding load of the first male spline portion 10a with respect to the first female spline portion 6a) F1 and the sliding of the second male shaft 3b with respect to the female shaft 2 The dynamic load (sliding load of the second male spline portion 10b with respect to the second female spline portion 6b) F2 is different from each other (F1 ≠ F2). Specifically, the sliding load F1 is made smaller than the sliding load F2 (F1 <F2). For example, the sliding load F1 is adjusted to about 1/4 to 3/4 of the sliding load F2. The method of adjusting the sliding loads F1 and F2 will be described later.

A pair of retaining members 5 are fixed to the ends of the female shaft 2 on both sides in the axial direction, one by one. As shown in FIG. 6, each of the pair of retaining members 5 includes a core metal 13 and an elastic material 14. The core metal 13 is made of a metal plate such as a steel plate, has an annular shape, and has an L-shaped cross section. The core metal 13 has a cylindrical portion 15 and an annular portion 16 bent at a right angle inward in the radial direction from the axial end portion of the cylindrical portion 15. The inner diameter of the annular portion 16 is smaller than the diameter of the tip circle of the male spline portion (first male spline portion 10a, second male spline portion 10b) and larger than the outer diameter of the small diameter tubular portions 8a and 8b. The elastic material 14 is made of an elastic material such as an elastomer such as rubber, is fixed to the annular portion 16 of the core metal 13 over the entire circumference, and has one seal lip 17. The entire radial inner portion of the annular portion 16 is covered with the elastic material 14.

In each of the pair of retaining members 5, the cylindrical portion 15 of the core metal 13 is fitted to the axial end portion of the female shaft 2 by tightening, and the cylindrical portion 15 of the annular portion 16 of the core metal 13 is fitted. By abutting the axial side surface of the female shaft 2 on the axial end surface of the female shaft 2, the female shaft 2 is fixed to the axial end portion of the female shaft 2 in a state of being positioned in the axial direction with respect to the female shaft 2.

In this state, the radial inner portion of the annular portion 16 of the core metal 13 projects radially inward from the tooth tip surface of the female spline portion 6, and the male shafts (first male shaft 3a, second male shaft 3b) ), It faces the stepped surfaces 11a and 11b in the axial direction. As a result, when the male shaft (first male shaft 3a, second male shaft 3b) moves in the direction of coming out from the inside of the female shaft 2, the retaining member 5 has the male shaft (as shown in FIG. 6, for example). The stepped surfaces 11a and 11b of the first male shaft 3a and the second male shaft 3b) are brought into contact with the retaining member 5 (specifically, the stepped surfaces 11a and 11b are brought into contact with the radial inner portion of the annular portion 16 as an elastic material. By making contact via 14), the large-diameter tubular portions 7a and 7b of the male shafts (first male shaft 3a and second male shaft 3b) are prevented from coming out from the inside of the female shaft 2.

The tip of the seal lip 17 of the elastic material 14 is in sliding contact with the outer peripheral surfaces of the small diameter tubular portions 8a and 8b of the male shafts (first male shaft 3a and second male shaft 3b) over the entire circumference. As a result, the retaining member 5 opens at the end of the gap existing between the inner peripheral surface of the female shaft 2 and the outer peripheral surface of the male shaft (first male shaft 3a, second male shaft 3b) on the outer space side. By sealing the space, the lubricating grease existing in the gap may leak to the external space through the end opening, or foreign matter existing in the external space may enter the gap through the end opening. Is prevented or suppressed.

In carrying out the present invention, instead of installing the retaining member 5, a holding portion bent inward in the radial direction is formed at the axial end of the female shaft by plastic working (caulking). By making the holding portion face the stepped surfaces 11a and 11b of the male shafts (first male shaft 3a and second male shaft 3b) in the axial direction, the male shafts (first male shaft 3a and second male shaft 3b) It is also possible to prevent the large-diameter tubular portions 7a and 7b from coming out from the inside of the female shaft. In particular, for the end portion on one side in the axial direction of the female shaft arranged in the vehicle interior where foreign matter is difficult to enter, it is easy to adopt a configuration in which a holding portion is formed instead of a configuration in which the retaining member 5 is installed. In any case, the number of parts can be reduced by adopting a configuration in which a holding portion is formed instead of the configuration in which the retaining member 5 is installed.

In this example, the fitting cylinder portion 9b (see FIG. 3B), which is the tip end portion (the end portion on the other side in the axial direction) of the second male shaft 3b, which is arranged outside the vehicle interior, is formed into a columnar shape by rubber. By internally fitting and fixing the configured closing member 18, the tip opening of the second male shaft 3b is closed (sealed). As a result, the closing member 18 prevents foreign matter such as muddy water from entering the internal space of the intermediate shaft 1 from the external space through the tip opening of the second male shaft 3b. In the case of carrying out the present invention, for example, as shown in FIG. 10, by internally fitting and fixing the bottomed cylindrical closing member 18a made of metal or synthetic resin to the fitting cylinder portion 9b, the second It is also possible to close (seal) the tip opening of the male shaft 3b.

On the other hand, in this example, the inside of the fitting cylinder portion 9a (see FIG. 3A), which is the tip end portion (one end portion on one side in the axial direction) of the first male shaft 3a, which is arranged in the vehicle interior, is closed. It is open without breaking (without sealing). As a result, when the intermediate shaft 1 expands and contracts in the axial direction, air is allowed to flow between the internal space and the external space of the intermediate shaft 1 through the tip opening of the first male shaft 3a. It is possible to prevent the pressure change in the space from occurring. When carrying out the present invention, a dustproof filter can be installed inside the fitting cylinder portion 9a which is the tip end portion of the first male shaft 3a. If such a configuration is adopted, dust and the like can be generated from the external space to the internal space while allowing air to flow between the internal space and the external space of the intermediate shaft 1 through the tip opening of the first male shaft 3a. It is possible to prevent foreign matter from entering.

The fitting cylinder 9a (see FIG. 3A), which is the tip of the first male shaft 3a, corresponds to the first yoke, which constitutes the universal joint 104a (see FIG. 24) corresponding to the first universal joint. The yoke 19a to be fitted is fixed to the outside. The fitting cylinder portion 9b (see FIG. 3B), which is the tip of the second male shaft 3b, corresponds to the second yoke, which constitutes the universal joint 104b (see FIG. 24) corresponding to the second universal joint. The yoke 19b to be fitted is fixed to the outside. In the illustrated example, each of the yokes 19a and 19b has a radial inner portion and a male axis (first) on the side surface of its own axial base end side (the side closer to the axial center position (chain line Cp) of the female axis 2). With respect to the male shaft (first male shaft 3a, second male shaft 3b) by the weld bead portions 20a and 20b extending over the entire circumference between the male shaft 3a and the second male shaft 3b). It is welded and joined.

In this example, for example, as shown in FIG. 9, the male shaft (first male shaft 3a, second male shaft 3b) is the female shaft 2 only up to the position where the weld bead portions 20a and 20b come into contact with the retaining member 5. It is not possible to enter inside. In other words, the retaining member 5 attaches the weld bead portions 20a and 20b to itself when the male shafts (first male shaft 3a and second male shaft 3b) move in the direction of entering the inside of the female shaft 2. The male shaft (first male shaft 3a) is brought into contact with each other (specifically, the weld bead portions 20a and 20b are brought into contact with the radial inner portion of the annular portion 16 via the elastic material 14 (see FIG. 6)). , The second male shaft 3b) is prevented from further entering the inside of the female shaft 2.

In the method of manufacturing the intermediate shaft 1 of this example, the spline engagement portion between the first female spline portion 6a and the first male spline portion 10a, and the spline engagement between the second female spline portion 6b and the second male spline portion 10b are used. It is provided with a heating familiarization process that is individually performed for each unit.

In the heating familiarization step, the axial base end side portion of the male shaft (3a, 3b) whose surface of the male spline portion (10a, 10b) is covered with the coating layer (4a, 4b) is inserted inside the female shaft 2. As a result, the male spline portion and the female spline portion (6a, 6b) are spline-engaged via the coating layer, and the spline engaging portion between the male spline portion and the female spline portion is lubricated with grease. .. That is, in this state, while heating the female shaft 2 (female spline portion) using a heater such as a high-frequency heater, the female spline portion and the male spline portion are reciprocally slid to slide the surface layer portion of the coating layer. Is heated to a temperature equal to or higher than the melting point of the coating layer to melt it. As a result, the surface of the coating layer is adapted to the surface of the female spline portion, and then the coating layer and the female shaft 2 are cooled.

In this example, the sliding load of the spline engaging portion between the male spline portion and the female spline portion immediately before the heating familiarization step is examined, and the sliding load is taken into consideration, and the female shaft 2 in the heating familiarization step is used. Adjust the heating conditions (heating temperature, heating time, etc.). As a result, the sliding load (F1, F2) of the spline engaging portion between the male spline portion and the female spline portion in the state where the heating familiarization step is completed is adjusted to a desired size.

In this example, the spline engaging portion between the first female spline portion 6a and the first male spline portion 10a and the spline engaging portion between the second female spline portion 6b and the second male spline portion 10b are used in a heating familiarization step. By making the heating conditions different in the above, the sliding load F1 of the first male shaft 3a with respect to the female shaft 2 and the sliding load F2 of the second male shaft 3b with respect to the female shaft 2 are made different from each other.

Next, an example of the behavior of the intermediate shaft 1 in which the two yokes 19a and 19b are fixed will be described.

In FIG. 1, the first male axis 3a is located in the axial middle portion of the movable range with respect to the female axis 2, and the second male axis 3b is located in the axial intermediate portion of the movable range with respect to the female axis 2. Indicates a state (nominal state). Regarding each of the first male shaft 3a and the second male shaft 3b, the movable range with respect to the female shaft 2 is the axial position where the stepped surfaces 11a and 11b are in contact with the retaining member 5 (for example, FIGS. 7 and 6). (See) to the axial position (see, for example, FIG. 9) where the weld bead portions 20a and 20b are in contact with the retaining member 5.

From the state shown in FIG. 1, when a force in the direction away from each other in the axial direction (a force in the direction of extending the intermediate shaft 1 in the axial direction) acts on the first male shaft 3a and the second male shaft 3b, first, sliding Axial sliding occurs only in the spline engaging portion between the first female spline portion 6a and the first male spline portion 10a, which is the side where the dynamic load is small, and the first male shaft 3a is relative to the female shaft 2. Moves to one side in the axial direction. FIG. 5 shows a state in which the first male axis 3a has moved to one end of the movable range with respect to the female axis 2 in the axial direction at this time.

From the state shown in FIG. 5, when a force in the direction away from each other in the axial direction (force in the direction of extending the intermediate shaft 1 in the axial direction) acts on the first male shaft 3a and the second male shaft 3b, a sliding load is applied. Axial sliding occurs only in the spline engaging portion between the second female spline portion 6b and the second male spline portion 10b, which is on the larger side, and the second male shaft 3b is an axis with respect to the female shaft 2. Move to the other side of the direction. FIG. 7 shows a state in which the second male axis 3b has moved to the other end of the movable range with respect to the female axis 2 in the axial direction at this time. Note that FIG. 7 shows a state in which the axial dimension of the intermediate shaft 1 to which the two yokes 19a and 19b are fixed is maximized.

From the state shown in FIG. 7, when a force in the direction of approaching each other in the axial direction (force in the direction of contracting the intermediate shaft 1 in the axial direction) acts on the first male shaft 3a and the second male shaft 3b, first, Axial sliding occurs only in the spline engaging portion between the first female spline portion 6a and the first male spline portion 10a, which is the side where the sliding load is small, and the first male shaft 3a becomes the female shaft 2. On the other hand, it moves to the other side in the axial direction. FIG. 8 shows a state in which the first male axis 3a has moved to the other end of the movable range with respect to the female axis 2 in the axial direction at this time.

From the state shown in FIG. 8, when a force in the direction of approaching each other in the axial direction (force in the direction of contracting the intermediate shaft 1 in the axial direction) acts on the first male shaft 3a and the second male shaft 3b, it slides. Axial sliding occurs only in the spline engaging portion between the second female spline portion 6b and the second male spline portion 10b, which is on the side where the load is large, and the second male shaft 3b is relative to the female shaft 2. Move to one side in the axial direction. FIG. 9 shows a state in which the second male axis 3b has moved to one end of the movable range with respect to the female axis 2 in the axial direction at this time. Note that FIG. 9 shows a state in which the axial dimension of the intermediate shaft 1 to which the two yokes 19a and 19b are fixed is minimized. From the viewpoint of handling, the intermediate shaft 1 to which the two yokes 19a and 19b are fixed is packed and transported in the state shown in FIG. 9 from the manufacturing site of the intermediate shaft 1 to the assembly site of the steering device. It is advantageous.

For example, from the state shown in FIG. 8, a force in a direction in which the intermediate shaft 1 approaches each other in the axial direction (a force in a direction in which the intermediate shaft 1 is contracted in the axial direction) acts on the first male shaft 3a and the second male shaft 3b. As a result, after the second male axis 3b moves to the axially intermediate portion of the movable range with respect to the female axis 2, the force in the direction away from each other with respect to the first male axis 3a and the second male axis 3b ( When the first male shaft 3a moves to the axially intermediate portion of the movable range with respect to the female shaft 2 by the action of the force in the direction of extending the intermediate shaft 1 in the axial direction, the state shown in FIG. 1 is obtained.

In the structure of this example, when the volume of the internal space of the intermediate shaft 1 changes as the intermediate shaft 1 expands and contracts in the axial direction, the intermediate shaft 1 passes through the tip opening of the first male shaft 3a. The flow of air between the internal space and the external space can prevent a pressure change from occurring in the internal space of the intermediate shaft 1. Therefore, the operation of the intermediate shaft 1 expanding and contracting in the axial direction can be smoothly performed.

Since the intermediate shaft 1 of this example as described above is formed by combining three dividing shafts (female shaft 2, first male shaft 3a, second male shaft 3b), two split shafts (female shaft, male). Compared to an intermediate shaft that is a combination of shafts), it is easier to secure a large expansion and contraction stroke.

Further, in the intermediate shaft 1 of this example, the female shaft 2, the first male shaft 3a, and the second male shaft 3b are located only on one of the outer peripheral surface and the inner peripheral surface. , Has a spline portion. For this reason, it becomes easier to form the spline portion with higher accuracy than the structure having the spline portion on each of the outer peripheral surface and the inner peripheral surface like the medium-diameter shaft constituting the conventional intermediate shaft described above. .. Therefore, the manufacturing cost of the intermediate shaft 1 can be suppressed accordingly.

Further, in the intermediate shaft 1 of this example, of the female shaft 2, the first male shaft 3a, and the second male shaft 3b, the first male shaft 3a and the second male shaft 3b have the same specifications. Therefore, the types of parts constituting the intermediate shaft 1 can be reduced accordingly. Therefore, in this respect as well, the manufacturing cost of the intermediate shaft 1 can be suppressed.

Further, in this example, the sliding load F1 of the first male shaft 3a with respect to the female shaft 2 and the sliding load F2 of the second male shaft 3b with respect to the female shaft 2 are made different from each other (F1 ≠ F2). Therefore, when a force in the direction of expanding and contracting the intermediate shaft 1 acts on the first male shaft 3a and the second male shaft 3b, the first male shaft 3a and the second male shaft 3a and the second male shaft 3a and the second male shaft 3a are in a predetermined order. The shaft 3b can be moved in the axial direction with respect to the female shaft 2. Therefore, the expansion / contraction operation of the intermediate shaft 1 can be stably performed. In addition, the work of assembling and removing the intermediate shaft 1 with respect to the steering device can be easily performed.

For example, in the cabtilt state of a large truck as shown by a chain line in FIG. 24, the intermediate shaft 1 of this example is in a state in which the total length is greatly extended as shown in FIG. When the intermediate shaft 1 is removed from the vehicle for maintenance of the steering device in such a cab-displaced state, if there is a work instruction to remove the intermediate shaft 1 from one end in the axial direction, the one side in the axial direction After removing the end portion, as shown in FIGS. 7 to 8, only the first male shaft 3a can be displaced to the other side in the axial direction with a light force with respect to the female shaft 2, so that the intermediate shaft 1 Easy to remove.

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIGS. 11-16.

In the intermediate shaft 1a of this example, the female shaft 2a has a relief recess 21 which is concave outward in the radial direction and corresponds to an inner relief recess 21 at one end in the axial direction of the inner peripheral surface over the entire circumference. That is, the relief recess 21 is arranged on the inner peripheral surface of the female shaft 2a, which is adjacent to one side of the first female spline portion 6a in the axial direction.

The relief recess 21 has an inner diameter larger than the diameter of the circumscribed circle of the first coating layer 4a (the portion of the first coating layer 4a that covers the tooth tip surface of the first male spline portion 10a) that covers the first male spline portion 10a. And has an axial dimension smaller than the axial dimension of the first male spline portion 10a. Therefore, as shown in FIGS. 15 and 16, the state in which the first male axis 3a has moved to one end of the movable range with respect to the female axis 2a in the axial direction, in other words, the first male axis 3a. In the state where the intermediate shaft 1a is moved to the end in the direction of increasing the axial dimension, one side portion (La portion in FIG. 16) of the first male spline portion 10a engages with the relief recess 21. Instead, it faces the relief recess 21 in the radial direction through a gap, and only the other side portion in the axial direction (Lb portion in FIG. 16) is spline-engaged with the first female spline portion 6a.

In the intermediate shaft 1a of this example having the above configuration, as shown in FIG. 15, the first male spline portion 10a of the first male shaft 3a is in a state where the total length of the intermediate shaft 1a is greatly extended (cablit state). Is spline-engaged with the first female spline portion 6a only on the other side portion in the axial direction (Lb portion in FIG. 16). That is, in this state, the engagement length of the first male spline portion 10a with respect to the first female spline portion 6a is shorter than that of the first example of the embodiment. Therefore, the sliding load of the first male shaft 3a with respect to the female shaft 2a in this state can be made smaller than that of the first example of the embodiment. Therefore, the work of removing the intermediate shaft 1a from the vehicle can be performed more easily in the cabtilt state.
Other configurations and effects are the same as in the first example of the embodiment.

[Third example of the embodiment]
A third example of the embodiment of the present invention will be described with reference to FIGS. 17 and 18.

In the intermediate shaft 1b of this example, the female shaft 2b is a relief recess corresponding to an inner relief recess in a portion of the inner peripheral surface sandwiched between the first female spline portion 6c and the second female spline portion 6d. Has 21a. In particular, in this example, the relief recess 21a is arranged at the central portion in the axial direction of the inner peripheral surface of the female shaft 2b. In this example, the female spline portion provided on the inner peripheral surface of the female shaft 2b is located on one side in the axial direction with respect to the relief recess 21a, and the first female spline portion 6c and the other side in the axial direction with respect to the relief recess 21a. It is divided into two parts with a second female spline portion 6d located at. In this example, the first female spline portion 6c and the second female spline portion 6d are arranged in different phases with respect to the circumferential direction. However, when the present invention is carried out, the first female spline portion 6c and the second female spline portion 6d may be arranged in phase with each other in the circumferential direction.

In the structure of this example, as shown in FIG. 18, the axial dimension of the intermediate shaft 1b to which the two yokes 19a and 19b are fixed is minimized, in other words, the first male shaft 3a and the second male. In a state where each of the shaft 3b and the shaft 3b has moved to the end in the direction of reducing the axial dimension of the intermediate shaft 1b, the other side portion in the axial direction of the first male spline portion 10a of the first male shaft 3a escapes. The recess 21a is radially opposed to one side in the axial direction through a gap, and only one side in the axial direction is spline-engaged with the first female spline portion 6c. On the other hand, in the second male spline portion 10b of the second male shaft 3b, one side portion in the axial direction faces the other side portion in the axial direction of the relief recess 21a in the radial direction through a gap, and the other side portion in the axial direction thereof. Only the side portion spline engages with the second female spline portion 6d. Therefore, in the state shown in FIG. 18, the sliding load of the first male shaft 3a with respect to the female shaft 2b and the sliding load of the second male shaft 3b with respect to the female shaft 2b are applied to the first example of the embodiment. Can be made smaller than in the case of. Therefore, when assembling the intermediate shaft 1b of this example to the steering device from the state shown in FIG. 18, the intermediate shaft 1b is extended in the axial direction, that is, the first male shaft with respect to the female shaft 2b. It becomes easy to move 3a to one side in the axial direction and to move the second male shaft 3b to the other side in the axial direction with respect to the female shaft 2b.
Other configurations and effects are the same as in the first and second embodiments of the embodiment.

[Fourth Example of Embodiment]
A fourth example of the embodiment of the present invention will be described with reference to FIGS. 19 to 23.

In the intermediate shaft 1c of this example, the relief recess 21b provided on the inner peripheral surface of the female shaft 2c, which corresponds to the inner relief recess, is located at the axial center position of the female shaft 2c in the inner peripheral surface of the female shaft 2c. It is arranged in a portion adjacent to the other side in the axial direction of the chain line Cp).

In the structure of this example, as shown in FIG. 20, the first male spline portion 10a of the first male shaft 3a is in a state where the axial dimension of the intermediate shaft 1b to which the two yokes 19a and 19b are fixed is minimized. Spline-engages the female spline portion 6c with its axial overall length. On the other hand, in the second male spline portion 10b of the second male shaft 3b, one side portion in the axial direction faces the relief recess 21a in the radial direction through a gap, and only the other side portion in the axial direction is female. Spline engages with spline portion 6d. Therefore, the sliding load of the second male shaft 3b with respect to the female shaft 2c in the state shown in FIG. 20 can be made smaller than that of the first example of the embodiment.

In this example, in a state where one side portion of the second male spline portion 10b of the second male shaft 3b in the axial direction faces the relief recess 21a in the radial direction through a gap, the second male shaft with respect to the female shaft 2c. The sliding load of 3b is adjusted to be smaller than the sliding load of the first male shaft 3a with respect to the female shaft 2c. Therefore, in this example, from the state shown in FIG. 20, a force in the direction in which the first male shaft 3a and the second male shaft 3b are separated from each other in the axial direction (force in the direction of extending the intermediate shaft 1 in the axial direction). When is acting, first, axial sliding occurs only in the spline engaging portion between the second female spline portion 6d and the second male spline portion 10b, which is the side where the sliding load is small, and the second male shaft 3b moves to the other side in the axial direction with respect to the female axis 2. FIG. 21 shows a state in which the second male shaft 3b has moved to the axially intermediate portion of the movable range with respect to the female shaft 2, more specifically, the second male spline portion 10b of the second male shaft 3b. Indicates a state in which the total length in the axial direction of the above has moved to a position where the spline engages with the second female spline portion 6d.

In this example, in the state where the total length in the axial direction of the second male spline portion 10b of the second male shaft 3b is spline-engaged with the second female spline portion 6d, the same as in the case of the first example of the embodiment. The sliding load of the second male shaft 3b with respect to the female shaft 2c is adjusted to be larger than the sliding load of the first male shaft 3a with respect to the female shaft 2c. Therefore, from the state shown in FIG. 21, when a force in the direction away from each other in the axial direction (a force in the direction of extending the intermediate shaft 1 in the axial direction) acts on the first male shaft 3a and the second male shaft 3b. Axial sliding occurs only in the spline engaging portion between the first female spline portion 6c and the first male spline portion 10a, which is the side where the sliding load is small, and the first male shaft 3a becomes the female shaft 2. On the other hand, it moves to one side in the axial direction. FIG. 22 shows a state in which the first male axis 3a has moved to one end of the movable range with respect to the female axis 2 in the axial direction at this time.

From the state shown in FIG. 22, when a force in the direction away from each other in the axial direction (force in the direction of extending the intermediate shaft 1 in the axial direction) acts on the first male shaft 3a and the second male shaft 3b, a sliding load is applied. Axial sliding occurs only in the spline engaging portion between the second female spline portion 6d and the second male spline portion 10b, which is on the larger side, and the second male shaft 3b is an axis with respect to the female shaft 2. Move to the other side of the direction. FIG. 23 shows a state in which the second male axis 3b has moved to the other end in the axial direction of the movable range with respect to the female axis 2 at this time. Note that FIG. 23 shows a state in which the axial dimension of the intermediate shaft 1c to which the two yokes 19a and 19b are fixed is maximized.

In the structure of this example, for example, when the intermediate shaft 1c is attached to the vehicle, the work of moving the second male shaft 3b to the other side in the axial direction with respect to the female shaft 2c is performed first from the state shown in FIG. If instructed, the operator can perform this work with a light force and attach the intermediate shaft 1c to the vehicle.
Other configurations and effects are the same as those of the first to third examples of the embodiment.

The structures of the above-described embodiments can be appropriately combined and implemented as long as there is no contradiction.
When the intermediate shaft of the present invention is implemented, the outer relief recess formed on the inner peripheral surface of the female shaft is arranged on the inner peripheral surface of the female shaft, which is adjacent to the other side in the axial direction of the second female spline portion. You can also do it.
When the intermediate shaft of the present invention is implemented, the inner relief recess formed on the inner peripheral surface of the female shaft is located on the inner peripheral surface of the female shaft, which is adjacent to one side of the female shaft at the axial center position in the axial direction. It can also be placed.
The intermediate shaft of the present invention can be used by being incorporated in a steering device for various vehicles, not limited to a steering device for a large truck.
When the intermediate shaft of the present invention is used by incorporating it into a steering device for an ordinary passenger car, the intermediate shaft shrinks in total length when an impact load is applied from the steering gear unit side in the event of a collision, so that the impact It is possible to prevent the load from being transmitted to the steering shaft and prevent the steering wheel from being pushed up toward the driver.

1, 1a to 1c Intermediate shaft 2, 2a to 2c Female shaft 3a, 3c 1st male shaft 3b, 3d 2nd male shaft 4a 1st coating layer 4b 2nd coating layer 5 Retaining member 6 Female spline part 6a 1st female Spline part 6b 2nd female spline part 7a, 7b Large diameter cylinder part 8a, 8b Small diameter cylinder part 9a, 9b Fitting cylinder part 10a 1st male spline part 10b 2nd male spline part 11a, 11b Step surface 12a, 12b Step surface 13 Core metal 14 Elastic material 15 Cylindrical part 16 Circular part 17 Seal lip 18, 18a Closing member 19a, 19b York 20a, 20b Welded bead part 21, 21a, 21b Relief recess 101 Steering wheel 102 Steering shaft 103 Intermediate shaft 104a, 104b Universal joint 105 Steering gear unit 106 Female shaft 107 Male shaft 108 Cabin 109 Tilt shaft

Claims (14)

It is configured in a tubular shape with both ends in the axial direction open, has a first female spline on one side in the axial direction of the inner peripheral surface, and has a second female spline on the other side in the axial direction of the inner peripheral surface. A female shaft with a part and
A first male shaft having a first male spline portion spline-engaged with the first female spline portion on the outer peripheral surface of the other side portion in the axial direction.
A second male shaft having a second male spline portion spline-engaged with the second female spline portion on the outer peripheral surface of one side portion in the axial direction.
A first yoke that constitutes a first universal joint and is fixed to one end of the first male shaft in the axial direction.
A second yoke forming a second universal joint, which is fixed to the other end of the second male shaft in the axial direction, is provided.
The first male axis and the second male axis have the same specifications.
Intermediate shaft. The same specifications have the same shape and dimensions.
The intermediate shaft according to claim 1. A first coating layer made of synthetic resin covering the first male spline portion and a second coating layer made of synthetic resin covering the second male spline portion are further provided.
The first female spline portion and the first male spline portion are spline-engaged via the first coating layer.
The second female spline portion and the second male spline portion are spline-engaged via the second coating layer.
The intermediate shaft according to claim 1 or 2. Each of the spline engaging portion between the first female spline portion and the first male spline portion and the spline engaging portion between the second female spline portion and the second male spline portion is lubricated by grease. Yes,
The intermediate shaft according to any one of claims 1 to 3. The sliding load of the first male shaft on the female shaft and the sliding load of the second male shaft on the female shaft are different from each other.
The intermediate shaft according to any one of claims 1 to 4. Each of the first male shaft and the second male shaft is formed in a tubular shape with both ends in the axial direction open.
The intermediate shaft according to any one of claims 1 to 5. Only one of the end opening on one side in the axial direction of the first male axis and the end opening on the other side in the axial direction of the second male axis is closed by the closing member. Is
The intermediate shaft according to claim 6. The female shaft is at least one of a portion of the inner peripheral surface adjacent to one side in the axial direction of the first female spline portion and a portion adjacent to the other side in the axial direction of the second female spline portion. When the first male shaft or the second male shaft existing inside the portion in the radial direction moves to the end in the direction of increasing the axial dimension of the intermediate shaft, the first male shaft or the portion It has an outer relief recess that is radially opposed to only a part of the first male spline portion or the second male spline portion in the axial direction provided by the second male shaft through a gap.
The intermediate shaft according to any one of claims 1 to 7. The female shaft has the first male shaft and the second male shaft in a portion of the inner peripheral surface sandwiched between the first female spline portion and the second female spline portion in the axial direction. When each moves to the end in the direction of reducing the axial dimension of the intermediate shaft, only a part of each of the first male spline portion and the second male spline portion in the axial direction and the diameter through the gap. Has inner relief recesses facing in the direction,
The intermediate shaft according to any one of claims 1 to 8. The female shaft has the first male shaft and the second male shaft in a portion of the inner peripheral surface sandwiched between the first female spline portion and the second female spline portion in the axial direction. When each moves to the end in the direction of reducing the axial dimension of the intermediate shaft, the axial direction of one of the first male spline portion and the second male spline portion is one. It has an inner relief recess that opposes in the radial direction only through the portion and the gap.
The intermediate shaft according to any one of claims 1 to 8. The first female spline portion and the second female spline portion are arranged in the same phase with respect to the circumferential direction and are formed continuously in the axial direction.
The intermediate shaft according to any one of claims 1 to 8. The first female spline portion and the second female spline portion are arranged in different phases with respect to the circumferential direction.
The intermediate shaft according to any one of claims 1 to 10. The method for manufacturing an intermediate shaft according to any one of claims 4 to 12, which directly or indirectly cites claim 3 or claim 3.
The spline engaging portion between the first female spline portion and the first male spline portion and the spline engaging portion between the second female spline portion and the second male spline portion are individually arranged. Equipped with a heating familiar process
In the heating familiarization step, the female spline portion and the male spline portion are reciprocally slid while heating the female spline portion in a state where the female spline portion and the male spline portion are spline-engaged via the coating layer. By moving, the surface layer portion of the coating layer is heated to a temperature equal to or higher than the melting point of the coating layer and melted, so that the surface of the coating layer is adapted to the surface of the female spline portion, and then the coating is applied. The process of cooling the layer and female shaft,
Manufacturing method of intermediate shaft. The spline engaging portion between the first female spline portion and the first male spline portion, and the spline engaging portion between the second female spline portion and the second male spline portion, the female in the heating familiarization step. By making the heating conditions of the spline portion different, the sliding load of the first male shaft with respect to the female shaft and the sliding load of the second male shaft with respect to the female shaft are made different from each other.
The method for manufacturing an intermediate shaft according to claim 13.

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