Clamping device, method of manufacturing the clamping device, and steering device

Abstract

To provide a clamping device which can be reduced in deformation resistance during fastening a bolt, and is adequate for transmitting high torque.SOLUTION: The clamping device comprises a cylindrical basal portion 20, and a pair of flange portions 21a, 21b. The basal portion 20 has: an axially extending through-hole 25; an axially extending first slit 22 which is arranged at one circumferential place, and has a one-side end in an axially direction and functioning as a first closed end 30, and has the other-side end in the axially direction and functioning as the end on one axial side and a first opening end 31 as the end on the other axial side functioning, and a second slit 26 arranged on the opposite side of the first slit 22 with respect to the radial direction and extending in the axial direction, and having a second closed end 32 as the end on one axial side and a second opening end 33 as the end on the other axial side, the second closed end 32 of the second slit 26 is arranged at a position which is more axial side than the first closed end 30 of the first slit 22.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure relates to a clamping device, a method for manufacturing the clamping device, and a steering device including the clamping device. [Background technology]

[0002] A steering device for an automobile is used to impart a steering angle to a steering wheel.

[0003] In a steering device, the rotation of the steering wheel is transmitted to the pinion shaft of the steering gear unit via a steering shaft, an intermediate shaft, etc. The rotation of the pinion shaft is converted into linear motion of the rack shaft of the steering gear unit, which gives the steered wheels a steering angle according to the amount of rotation of the steering wheel.

[0004] In a steering device, ends of two rotating shafts that are not coaxial with each other, such as a steering shaft and an intermediate shaft, are connected to each other via a universal joint so as to be able to transmit torque.

[0005] The universal joint includes a pair of yokes and a cross shaft.

[0006] The yoke that constitutes the universal joint is a type of clamp device, and has a cylindrical base portion, a pair of flange portions, and a pair of arm portions connected to the cross shaft.

[0007] The base has a first slit extending in the axial direction at one location in the circumferential direction and is configured to be able to reduce its diameter. An end of a rotating shaft such as a steering shaft or a pinion shaft is inserted inside the base. A pair of flanges is provided on both sides of the first slit in the circumferential direction. The pair of flanges has mounting holes arranged coaxially. The yoke is fixed to the rotating shaft by the base tightening the rotating shaft with a bolt inserted through one mounting hole provided in one of the pair of flanges and screwing it into the other mounting hole provided in the other flange.

[0008] Yokes are roughly classified into so-called open slit type yokes and so-called closed slit type yokes depending on the structure of the first slit provided in the base.

[0009] The closed slit type yoke is preferably used for applications that transmit high torque because it is easier to ensure strength compared to the open slit type yoke.

[0010] Fig. 23 shows an example of a conventional structure of an open-slit type yoke 100a, and Fig. 24 shows an example of a conventional structure of a closed-slit type yoke 100b.

[0011] The open slit type yoke 100a has a first slit 102a with both axial ends open at one location on the base 101a, while the closed slit type yoke 100b has a first slit 102b with one axial end closed and the other axial end open at one location on the base 101b.

[0012] The closed slit type yoke 100b has a higher flexural rigidity and tends to have a higher deformation resistance than the open slit type yoke 100a. Therefore, when a bolt (not shown) is tightened with the same torque, the tightening force of the closed slit type yoke 100b tends to be smaller than the tightening force of the open slit type yoke 100a.

[0013] When the closed slit type yoke 100b is incorporated into a column-assist type electric power steering device that transmits high torque, the end of the rotating shaft may slide slightly against the base 101b due to insufficient tightening force. As a result, damage such as fretting wear and fretting corrosion may progress to the female serration teeth provided on the inner peripheral surface of the base 101b and / or the male serration teeth provided on the outer peripheral surface of the rotating shaft.

[0014] In view of these circumstances, techniques have been devised for reducing the deformation resistance of closed slit type yokes when the bolts are tightened.

[0015] Japanese Patent Application Publication No. 2018-128077 describes a technology for reducing deformation resistance when tightening a bolt by forming a second slit of the same dimensions as the first slit in a part of the base that is located radially opposite the first slit.

[0016] JP 2017-137895 A describes a technology for reducing deformation resistance when tightening a bolt by forming a partial cylindrical notch in the radially opposite half of the end of the base from the first slit. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] JP 2018-128077 A [Patent Document 2] JP 2017-137895 A Summary of the Invention [Problem to be solved by the invention]

[0018] In the yoke of the conventional structure described in JP 2018-128077 A, the central axis of the mounting hole, which is the center for tightening the bolt, is positioned so as to be perpendicular to the central axis of the base, and the first slit and the second slit are positioned in a direction perpendicular to the central axis of the mounting hole.

[0019] As a result, the fastening force from the base becomes uneven in the circumferential direction, and even when the bolt is fastened, a gap is likely to remain between the portion of the inner peripheral surface of the base near the first and second slits and the outer peripheral surface of the shaft. Therefore, when used in an application for transmitting high torque, the end of the rotating shaft tilts relative to the base, centered on the bolt, and the female serration teeth near the first and second slits are likely to wear out or be damaged.

[0020] The yoke of the conventional structure described in JP 2018-128077 A can reduce deformation resistance when the bolt is tightened, but is unsuitable for applications that transmit high torque.

[0021] The conventional yoke described in JP 2017-137895 A has a partially cylindrical notch at the end of the base, which makes the engagement area between the base and the rotating shaft excessively small. Also, when used for transmitting high torque, the end of the rotating shaft is tilted toward the notch relative to the base, making the female serration teeth more susceptible to wear and damage.

[0022] The yoke of the conventional structure described in JP 2017-137895 A can reduce deformation resistance when the bolts are tightened, but is unsuitable for applications that transmit high torque.

[0023] The problem described above is not limited to yokes that constitute universal joints that connect two rotating shafts that are not arranged coaxially, but can also occur in clamping devices other than yokes, such as coupling devices that connect two rotating shafts that are arranged coaxially.

[0024] An object of the present disclosure is to provide a clamp device that can reduce deformation resistance when tightening a bolt and is suitable for transmitting high torque. [Means for solving the problem]

[0025] A clamp device according to one aspect of the present disclosure includes a cylindrical base and a pair of flanges.

[0026] The base has an insertion hole extending in the axial direction, a first slit arranged at one location in the circumferential direction and extending in the axial direction, with an end on one axial side being a first closed end and an end on the other axial side being a first open end, and a second slit arranged on the opposite side of the first slit in the radial direction and extending in the axial direction, with an end on one axial side being a second closed end and an end on the other axial side being a second open end.

[0027] The pair of flange portions have coaxial mounting holes and are disposed on both sides of the first slit in the circumferential direction.

[0028] The central axes of the pair of mounting holes are disposed at skewed positions with respect to the central axis of the insertion hole.

[0029] The second closed end of the second slit is disposed on the other axial side of the first closed end of the first slit.

[0030] In the clamp device according to one aspect of the present disclosure, the first closed end of the first slit is disposed on one side in the axial direction relative to the central axis of the pair of mounting holes.

[0031] In the clamp device according to one aspect of the present disclosure, at least a portion of the second closed end of the second slit is disposed on the other axial side of the central axis of the pair of mounting holes.

[0032] In a clamp device according to one aspect of the present disclosure, the first closed end of the first slit and the second closed end of the second slit are formed by concave cylindrical surfaces and are arranged on the same imaginary cylindrical surface.

[0033] In the clamp device according to one aspect of the present disclosure, the insertion hole has a non-circular cross-sectional shape.

[0034] In this case, the base portion may have female serration teeth on the inner peripheral surface, or may have two parallel flat surfaces on the inner peripheral surface, or may have three or more flat surfaces on the inner peripheral surface.

[0035] In the clamp device according to one aspect of the present disclosure, the pair of flange portions are integral with the base portion.

[0036] Alternatively, the pair of flange portions may be separate from the base portion.

[0037] The clamp device according to one aspect of the present disclosure further includes a connecting portion that is connected to another member in a torque-transmittable manner.

[0038] In the clamp device according to one aspect of the present disclosure, the connecting portion is made of a pair of arms provided adjacent to one side of the base in the axial direction. In this case, the clamp device is made of a yoke constituting a universal joint.

[0039] In a clamp device according to one embodiment of the present disclosure, one of the pair of arm portions is positioned at a position where its phase in the circumferential direction coincides with the first slit, and the other of the pair of arm portions is positioned at a position where its phase in the circumferential direction coincides with the second slit.

[0040] In the clamp device according to one aspect of the present disclosure, the connecting portion may be configured by a male shaft portion having male serration teeth or male spline teeth on an outer circumferential surface, a female shaft portion having female serration teeth or female spline teeth on an inner circumferential surface, or a key engagement portion, which are arranged coaxially with the base and adjacent to the one axial side of the base. In this case, the clamp device can connect the ends of two coaxially arranged rotating shafts to each other in a torque transmittable manner by fitting the connecting portion to an end of a mating member so as not to rotate relative to the mating member.

[0041] In the method for manufacturing the clamp device according to the aspect of the present disclosure, the first slit and the second slit are machined at once using a common cutter, that is, the first slit and the second slit are formed by simultaneous machining.

[0042] A steering device according to one embodiment of the present disclosure includes two rotating shafts that rotate by operation of a steering wheel and are not arranged on the same axis, and a universal joint that connects the ends of the two rotating shafts to each other so as to transmit torque.

[0043] The universal joint includes a pair of yokes and a cross shaft.

[0044] In the clamp device according to the above aspect, at least one of the pair of yokes has the pair of arm portions.

[0045] A steering device according to one embodiment of the present disclosure includes two coaxially arranged rotating shafts that rotate by operation of a steering wheel, and a coupling device that connects the ends of the two rotating shafts to each other so as to transmit torque.

[0046] The connecting device is the clamp device according to the aspect not having the connecting portion, or the clamp device according to the aspect having the connecting portion other than the pair of arm portions. Effect of the Invention

[0047] According to the clamp device according to one aspect of the present disclosure, it is possible to reduce the deformation resistance when tightening a bolt and to transmit high torque. [Brief description of the drawings]

[0048] [Figure 1] FIG. 1 is a partial cutaway side view showing a steering device according to a first example of an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3]FIG. 3 is a side view of the universal joint that connects the intermediate shaft and the pinion shaft in the first example. [Figure 4] FIG. 4 is a diagram showing a first yoke which is a clamp device of the first example. [Diagram 5] FIG. 5 is a diagram showing the first yoke of the first example rotated 180 degrees around the central axis from the state shown in FIG. [Figure 6] FIG. 6 is a view of the first yoke of the first example seen from above in FIG. [Figure 7] FIG. 7 is a view of the first yoke of the first example seen from below in FIG. [Figure 8] FIG. 8 is an end view of the first yoke of the first example as viewed from the other axial side of FIG. [Figure 9] FIG. 9 is an end view of the first yoke of the first example as viewed from one axial side of FIG. [Figure 10] FIG. 10 is a cross-sectional view taken along line BB in FIG. [Figure 11] FIG. 11 is a perspective view of the first yoke of the first example as viewed from the other axial side of FIG. [Figure 12] FIG. 12 is a perspective view showing the first yoke of the first example rotated 180 degrees about the central axis from the state shown in FIG. [Figure 13] FIG. 13 is a perspective view of the first yoke of the first example as viewed from one axial side in FIG. [Figure 14] FIG. 14 is a perspective view showing the first yoke of the first example rotated 180 degrees about the central axis from the state shown in FIG. [Figure 15] FIG. 15 is a schematic diagram showing a process of forming a first slit and a second slit in the first yoke by using a common cutter. [Figure 16] FIG. 16 is a diagram corresponding to FIG. 4 and relating to a second example of the embodiment of the present disclosure. [Figure 17] FIG. 17 is a diagram corresponding to FIG. 10 and relating to the second example. [Figure 18] FIG. 18 is a diagram corresponding to FIG. 4 and relating to a third example of the embodiment of the present disclosure. [Figure 19] FIG. 19 is a diagram corresponding to FIG. 8 and relating to the third example. [Figure 20] FIG. 20 is a side view showing an intermediate shaft constituting a steering device according to a fourth example of an embodiment of the present disclosure. [Figure 21] FIG. 21 is a diagram corresponding to FIG. 4 and relating to the fourth example. [Figure 22] FIG. 22 is a diagram corresponding to FIG. 10 and relating to the fourth example. [Figure 23] FIG. 23 is a perspective view showing an example of a conventional structure of an open slit type yoke. [Figure 24] FIG. 24 is a perspective view showing an example of a conventional structure of a closed slit type yoke. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 15. FIG.

[0050] This example is an example in which a clamp device according to one aspect of the present disclosure is applied to a yoke that constitutes a universal joint incorporated in a steering device for an automobile.

[0051] [Outline of the steering system] The steering device 1 is a column-assist type electric power steering device, the overall configuration of which is shown in FIG.

[0052] The steering device 1 includes a steering wheel 2, a steering shaft 3, a steering column 4, two universal joints 5a, 5b, an intermediate shaft 6, a steering gear unit 7, a pair of tie rods 8, and an electric assist device 9.

[0053] The steering shaft 3 is rotatably supported inside a steering column 4 supported on the vehicle body. A steering wheel 2 operated by a driver is fixed to the rear end of the steering shaft 3. The front end of the steering shaft 3 is inserted inside a gear housing 10 fixed to the steering column 4, and is connected to an output shaft 12 via a torsion bar 11.

[0054] The front-rear direction refers to the front-rear direction of the vehicle in which the steering device 1 is mounted.

[0055] The rotation of the output shaft 12 is transmitted to a pinion shaft 13 constituting a steering gear unit 7 via two universal joints 5a, 5b and an intermediate shaft 6. The rotation of the pinion shaft 13 is converted into linear motion of a rack shaft meshed with the pinion shaft 13, which pushes and pulls a pair of tie rods 8. As a result, a steering angle according to the amount of operation of the steering wheel 2 is imparted to the steered wheels.

[0056] As shown in FIG. 2, the electric assist device 9 includes a torque sensor 14, an ECU (not shown), an electric motor 15, and a worm reduction gear 16.

[0057] The torque sensor 14 is disposed around the output shaft 12 and detects the relative torsion direction and amount of torsion of the output shaft 12 with respect to the steering shaft 3. The ECU determines the assist torque based on the detection signal of the torque sensor 14 and a vehicle speed signal measured by a vehicle speed sensor (not shown), etc. The electric motor 15 is fixed to the gear housing 10, and the direction and amount of current flow are controlled by the ECU. The worm reduction gear 16 reduces the rotational force of the electric motor 15 and transmits it to the output shaft 12. The electric assist device 9 imparts an assist torque to the output shaft 12 and reduces the steering force required for the driver to operate the steering wheel 2.

[0058] The intermediate shaft 6 and the output shaft 12 are two rotating shafts that are not arranged coaxially and rotate by operating the steering wheel 2. The universal joint 5a connects the respective ends of the intermediate shaft 6 and the output shaft 12 to each other in a manner enabling torque transmission.

[0059] The intermediate shaft 6 and the pinion shaft 13 are two rotating shafts that are not arranged coaxially and rotate by operating the steering wheel 2. The universal joint 5b connects the respective ends of the intermediate shaft 6 and the pinion shaft 13 to each other in a manner capable of transmitting torque.

[0060] 3, the universal joint 5b is composed of a first yoke 17 corresponding to a clamp device fixed to an end of the pinion shaft 13, a second yoke 18 fixed to an end of the intermediate shaft 6, and a cross shaft 19. In this example, the clamp device according to one embodiment of the present disclosure is applied to the first yoke 17 of the first yoke 17 and second yoke 18 constituting the universal joint 5b.

[0061] The clamp device according to an embodiment of the present disclosure may be applied to the second yoke 18 instead of the first yoke 17, or may be applied to both the first yoke 17 and the second yoke 18. Additionally or alternatively, the clamp device according to an embodiment of the present disclosure may be applied to at least one of the pair of yokes constituting the universal joint 5a. In these cases, the same configuration as the first yoke is adopted, and therefore the description thereof is omitted in this specification.

[0062] The first yoke 17 will be described below with reference to FIGS.

[0063] [Yoke structure] The first yoke 17 is a so-called closed slit type yoke, and includes a cylindrical base portion 20 and a pair of flange portions 21a, 21b.

[0064] The base 20 has a first slit 22 extending in the axial direction at one location in the circumferential direction and is configured to be able to reduce its diameter. The pair of flange portions 21a, 21b are disposed on both sides of the first slit 22 in the circumferential direction of the base 20. The first yoke 17 is fixed to the pinion shaft 13 by tightening the base 20 to the end of the pinion shaft 13 by screwing a bolt 24 (see FIG. 3) inserted through a mounting hole 23a provided in one flange portion 21a into a mounting hole 23b provided in the other flange portion 21b and further tightening the bolt.

[0065] Unless otherwise specified, the axial direction, circumferential direction, and radial direction of the first yoke 17 refer to the axial direction, circumferential direction, and radial direction of the base 20. The front-to-back direction in Fig. 4 and Fig. 5, the up-to-down direction in Fig. 6 and Fig. 7, and the left-to-right direction in Fig. 8 and Fig. 9, which are directions perpendicular to the axial direction of the base 20, are referred to as first directions. The up-to-down direction in Fig. 4 and Fig. 5, the front-to-back direction in Fig. 6 and Fig. 7, and the left-to-right direction in Fig. 8 and Fig. 9, which are directions perpendicular to the axial direction and the first direction of the base 20, are referred to as second directions.

[0066] A slit is a narrow gap whose width is smaller than its length.

[0067] The first yoke 17 is made of a metal material by subjecting it to, for example, forging and cutting processes.

[0068] In this example, the tubular shape of the base 20 is specifically a substantially cylindrical shape.

[0069] The base portion 20 has an insertion hole 25, a first slit 22, and a second slit .

[0070] The insertion hole 25 extends in the axial direction of the base 20. In this example, the insertion hole 25 penetrates the base 20 in the axial direction. Specifically, the insertion hole 25 penetrates the radial center of the base 20 in the axial direction. That is, the central axis O of the insertion hole 25 is 25coincides with the central axis of the base 20. One axial end of the pinion shaft 13 is inserted into the insertion hole 25. The insertion hole is not limited to a through hole that passes through the base in the axial direction, but may be a bottomed hole that does not pass through the base in the axial direction.

[0071] The cross-sectional shape of the insertion hole 25 is determined arbitrarily depending on the application to which the clamp device is applied, particularly the presence or absence of torque transmission and the magnitude of the torque to be transmitted. In applications involving torque transmission, the insertion hole 25 has a non-circular cross-sectional shape. Non-circular shapes include a gear shape, an oval shape (a two-face shape), an ellipse shape, a polygonal shape, and the like.

[0072] In this example, the insertion hole 25 has a gear-shaped cross section. More specifically, the insertion hole 25 is configured as a serration hole in which female serration teeth 27 are arranged in the circumferential direction on the inner peripheral surface of the base portion 20. The female serration teeth 27 engage with male serration teeth 28 provided on the outer peripheral surface of the end portion of the pinion shaft 13 so as not to rotate relative to each other.

[0073] The base portion 20 has a toothless portion 29 where the female serration teeth 27 are not formed on a circumferential portion of the inner peripheral surface of the base portion 20. The toothless portion 29 is provided in a range of the inner peripheral surface of the base portion 20 that spans the first slit 22 in the circumferential direction. The toothless portion 29 is aligned with the central axis O of the insertion hole 25. 25 The inner diameter of the toothless portion 29 is the same as the diameter of the bottom circle of the female serration tooth 27.

[0074] Central axis O of the insertion hole 25 25 The central angle of the toothless portion 29 about the center is not particularly limited. In this example, 25 The central angle of the toothless portion 29 about the center is approximately 80 degrees.

[0075] The female serration teeth 27 and the toothless portion 29 are formed on the inner peripheral surface of the base portion 20 in a range from one end on one axial side to the other end on the other axial side.

[0076] The female serration teeth 27 and the toothless portion 29 are formed, for example, by broaching using a broach tool.

[0077] The first slit 22 is disposed at one location in the circumferential direction of the base 20 and extends in the axial direction. The length direction of the first slit 22 coincides with the axial direction, the width direction of the first slit 22 coincides with the first direction, and the depth direction of the first slit 22 coincides with the second direction.

[0078] The first slit 22 extends linearly in the axial direction. 22 is the central axis O of the insertion hole 25 25 are arranged approximately parallel to each other.

[0079] The first slits 22 open to the outer circumferential surface and the inner circumferential surface of the base portion 20 .

[0080] The first slit 22 is formed in a range extending from the end portion on the other axial side of the base portion 20 to the portion on one axial side.

[0081] An end portion of the first slit 22 on one axial side is a first closed end 30 that is closed in the axial direction, and an end portion of the first slit 22 on the other axial side is a first open end 31 that is open in the axial direction. That is, the first slit 22 does not open to an end face of the base 20 on one axial side, but opens to an end face of the base 20 on the other axial side. The first closed end 30 is located at one axial side portion of the base 20.

[0082] When viewed from the second direction, the first slit 22 has a rectangular opening shape that is long in the axial direction.

[0083] Width dimension W of the first slit 22 22 is constant over the entire length of the first slit 22 before the bolt 24 is tightened. However, the width dimension of the first slit may be varied depending on the axial position of the first slit.

[0084] The first closed end 30 of the first slit 22 is aligned with the central axis O of the insertion hole 25. 25and is constituted by a concave cylindrical surface having an arc-shaped cross section in a cross section perpendicular to the first direction. In other words, first closed end 30 is constituted by a partial cylindrical surface that is inclined toward one axial side as it goes radially outward and faces radially outward.

[0085] However, when implementing the present disclosure, the first closed end of the first slit can be formed by a plane perpendicular to the central axis of the insertion hole, or can be formed by a partial cylindrical surface that is approximately semicircular arc-shaped when viewed from the second direction.

[0086] The first closed end 30 of the first slit 22 is aligned with the central axis O of the mounting holes 23a, 23b. 23 In other words, the entire radial direction of first closed end 30 is aligned with center axis O of mounting holes 23a, 23b. 23 It is disposed on one axial side of the

[0087] Width dimension W of the first slit 22 22 The length dimension L of the first slit 22 at the radially intermediate portion 22 Ratio (L 22 / W 22 ) is not particularly limited, but in this example, the width dimension W of the first slit 22 is 22 The length dimension L of the first slit 22 at the radially intermediate portion 22 The ratio is approximately 9.

[0088] The first slits 22 are formed, for example, by cutting using a cutter which is a rotary cutting tool.

[0089] However, when implementing the present disclosure, the first slits may be formed by a method other than cutting.

[0090] The second slit 26 is disposed on the radially opposite side of the base 20 from the first slit 22 and extends in the axial direction. The length direction of the second slit 26 coincides with the axial direction, the width direction of the second slit 26 coincides with the first direction, and the depth direction of the second slit 26 coincides with the second direction.

[0091] In this example, the second slits 26 are disposed at positions whose phase in the circumferential direction differs from that of the first slits 22 by 180 degrees.

[0092] The second slit 26 extends linearly in the axial direction. 26 is the central axis O of the first slit 22 22 are arranged approximately parallel to each other.

[0093] The second slits 26 open to the outer circumferential surface and the inner circumferential surface of the base portion 20 .

[0094] The second slit 26 is formed in a range extending from the other axial end of the base portion 20 to the axial middle portion.

[0095] An end portion of the second slit 26 on one axial side is a second closed end 32 that is closed in the axial direction, and an end portion of the second slit 26 on the other axial side is a second open end 33 that is open in the axial direction. In other words, the second slit 26 does not open to an end face of the base 20 on one axial side, but opens to an end face of the base 20 on the other axial side. The second closed end 32 is located in the middle of the base 20 in the axial direction.

[0096] The second slit 26 has a rectangular opening shape that is long in the axial direction when viewed from the second direction.

[0097] Width dimension W of the second slit 26 26 The width dimension W of the second slit 26 is constant over the entire length of the second slit 26 before the bolt 24 is tightened. 26 is the width dimension W of the first slit 22 22However, the width dimension of the second slit may be different depending on the axial position of the second slit. Additionally or alternatively, the width dimension of the second slit may be different from the width dimension of the first slit.

[0098] The second closed end 32 of the second slit 26 is aligned with the central axis O of the insertion hole 25. 25 and is constituted by a concave cylindrical surface having an arc-shaped cross section in a cross section perpendicular to the first direction. In other words, second closed end 32 is constituted by a partial cylindrical surface that is inclined toward one axial side as it goes radially inward and faces radially inward.

[0099] In this example, the second closed end 32 of the second slit 26 and the first closed end 30 of the first slit 22 are disposed on the same imaginary cylindrical surface.

[0100] However, when implementing the present disclosure, the second closed end of the second slit can be formed by a plane perpendicular to the central axis of the insertion hole, or can be formed by a partial cylindrical surface that is approximately semicircular arc-shaped when viewed from the second direction.

[0101] The second closed end 32 of the second slit 26 is disposed on the other axial side of the first closed end 30 of the first slit 22. That is, the portion of the second closed end 32 located furthest on the one axial side is also disposed on the other axial side of the portion of the first closed end 30 located furthest on the other axial side. Specifically, the radially inner end portion of the second closed end 32 located furthest on the one axial side is also disposed on the other axial side of the radially inner end portion of the first closed end 30 located furthest on the other axial side.

[0102] In this example, at least a portion of the second closed end 32 of the second slit 26 is aligned with the central axis O of the mounting holes 23a, 23b. 23 It is disposed on the other axial side than the above.

[0103] In this example, the range from the radially outer end portion to the radially middle portion of the second closed end 32 is aligned along the central axis O of the mounting holes 23a, 23b. 23 The radially inner end of the second closed end 32 is disposed on the other axial side of the central axis O of the mounting holes 23a, 23b. 23 It is disposed on one axial side of the

[0104] However, when implementing the present disclosure, the entire radial direction of the second closed end may be disposed on the other axial side of the central axis of the mounting hole.

[0105] Length dimension L of the second slit 26 at the radially intermediate portion 26 is the length dimension L of the first slit 22 at the radially intermediate portion 22 Shorter than (L 26 <L 22 ).

[0106] Length dimension L of the first slit 22 22 The length dimension L of the second slit 26 26 Ratio (L 26 / L 22 ) is not particularly limited, but may be, for example, 0.1 to 0.7, and preferably 0.2 to 0.5. In this example, the length dimension L of the first slit 22 22 The length dimension L of the second slit 26 26 The ratio is approximately 0.4.

[0107] Width dimension W of the second slit 26 26 The length dimension L of the second slit 26 at the radially intermediate portion 26 Ratio (L 26 / W 26 ) is not particularly limited, but may be, for example, 1 to 6, and preferably 2 to 5. In this example, the width dimension W 26 The length dimension L of the second slit 26 at the radially intermediate portion 26 The ratio is approximately 4.

[0108] The second slits 26 are formed, for example, by cutting using a cutter, which is a rotary cutting tool.

[0109] However, when implementing the present disclosure, the second slits may be formed by a method other than cutting.

[0110] In this example, for example, as shown in FIG. 15, the first slit 22 and the second slit 26 can be processed by cutting using a common cutter 34.

[0111] When the first slit 22 and the second slit 26 are formed by the cutter 34, the cutter 34 is disposed on the other axial side of the first yoke 17. 34 oriented in the first direction and aligned parallel to the central axis O of the insertion hole 25 in the second direction. 25 The cutter 34 is then moved in parallel toward one side in the axial direction. This allows the first slit 22 and the second slit 26 to be machined at once (one-pass machining) using the common cutter 34. That is, the first slit 22 and the second slit 26 can be formed by simultaneous machining by moving a common rotary cutting tool back and forth in the axial direction only once. In this way, when the first slit 22 and the second slit 26 are machined simultaneously, the first closed end 30 of the first slit 22 and the second closed end 32 of the second slit 26 are positioned on the same imaginary cylindrical surface.

[0112] However, when implementing the present disclosure, the first slit and the second slit can be machined separately using different cutters, or can be machined separately using a common tool.

[0113] Outer diameter D of base 20 20 Axial dimension L of the base 20 20 Ratio (L 20 / D 20) is not particularly limited, but may be, for example, 1 or more and 3 or less, and preferably 1 or more and 1.5 or less. In this example, the outer diameter D 20 Axial dimension L of the base 20 20 The ratio is approximately 1.2.

[0114] The pair of flange portions 21a, 21b are disposed on both sides of the first slit 22 in the circumferential direction.

[0115] The pair of flange portions 21a, 21b are provided on the outer peripheral surface of the end portion on the other axial side of the base portion 20. The pair of flange portions 21a, 21b each protrude in the second direction from a portion of the outer peripheral surface of the base portion 20 that is located on both sides of the first slit 22 in the circumferential direction. Each of the pair of flange portions 21a, 21b has a plate shape.

[0116] In this example, the pair of flange portions 21a, 21b have a substantially semicircular side shape when viewed from the first direction.

[0117] In this example, the pair of flange portions 21 a, 21 b are integral with the base portion 20 .

[0118] The pair of flange portions 21a, 21b are spaced apart in the first direction and disposed approximately parallel to each other. A gap 35 is provided between the inner surfaces of the pair of flange portions 21a, 21b in the first direction. The gap 35 is continuous with the first slit 22 in the second direction. The gap 35 has the same size as the width dimension of the first slit 22 before the bolt 24 is tightened. The gap 35 can be formed by cutting the first slit 22 at the same time as the first slit 22 using a cutter, which is a rotary cutting tool.

[0119] The dimension between the outer surfaces of the pair of flange portions 21a, 21b (excluding a protruding tubular portion 46 described later) in the first direction is substantially the same as the outer diameter of the base portion 20 before the bolts 24 are tightened.

[0120] The pair of flanges 21a, 21b have mounting holes 23a, 23b on the same axis. 23 The central axis O of the mounting holes 23a and 23b faces the first direction. 23 is the central axis O of the insertion hole 25 25 are arranged in a twisted position.

[0121] In this example, one of the pair of mounting holes 23a, 23b, 23a, is a cylindrical bolt insertion hole, and the other of the pair of mounting holes 23a, 23b, 23b, is a screw hole.

[0122] However, when implementing the present disclosure, the pair of mounting holes may be cylindrical holes, in which case the diameter of the base is reduced by screwing a nut onto the tip of the bolt inserted through the pair of mounting holes.

[0123] Of the pair of flange portions 21a, 21b, one flange portion 21b has an overhanging tubular portion 46 that overhangs in a first direction on its outer surface. The overhanging tubular portion 46 has a female thread on its inner circumferential surface and constitutes a part of the mounting hole 23b.

[0124] The first yoke 17 further includes a connecting portion 36 for connecting to another member in a manner enabling torque transmission.

[0125] In this example, the connecting portion 36 is configured by a pair of arm portions 37a, 37b. The pair of arm portions 37a, 37b each extend in the axial direction and are disposed spaced apart from each other.

[0126] Each of the pair of arm portions 37a, 37b is configured to have a substantially plate-like shape. The pair of arm portions 37a, 37b are disposed adjacent to one axial side of the base portion 20. The base ends of the pair of arm portions 37a, 37b are connected to two positions on the radially opposite sides of the base portion 20 among the ends on one axial side of the base portion 20.

[0127] In the illustrated example, the pair of arm portions 37a, 37b are spaced apart in the second direction. In other words, the pair of arm portions 37a, 37b are arranged at positions that are circumferentially shifted in phase with the pair of flange portions 21a, 21b by 90 degrees.

[0128] However, when implementing the present disclosure, the pair of arm portions may be disposed spaced apart in the first direction, or may be disposed spaced apart in another direction.

[0129] Of the pair of arm portions 37a, 37b, the circumferential phase of one arm portion 37a matches the circumferential phase of the first slit 22, and the circumferential phase of the other arm portion 37b matches the circumferential phase of the second slit 26.

[0130] In this example, the pair of arm portions 37 a and 37 b are integrally formed with the base portion 20 .

[0131] The pair of arms 37a, 37b each have a through hole 38 that is a coaxially arranged through hole. A shaft portion constituting the cross shaft 19 is rotatably supported in the through hole 38 via a bearing cup.

[0132] To fix the first yoke 17 to the end of the pinion shaft 13, the end of the pinion shaft 13 is inserted into the insertion hole 25, and the male serration teeth 28 and the female serration teeth 27 are engaged by serration. The bolt 24 inserted through the mounting hole 23a provided in one flange portion 21a is screwed into the mounting hole 23b provided in the other flange portion 21b. The bolt 24 is then further tightened to reduce the width of the first slit 22 and the gap 35, and to increase the width of the second slit 26, thereby reducing the diameter of the base 20 and tightening the end of the pinion shaft 13 with the base 20. This fixes the first yoke 17 to the end of the pinion shaft 13. If necessary, the middle portion of the bolt 24 is engaged with the outer circumferential surface of the pinion shaft 13.

[0133] According to the first yoke 17 of the present embodiment, it is possible to reduce the deformation resistance when the bolt 24 is tightened, and also possible to transmit high torque.

[0134] The base 20 of the first yoke 17 in this example has the second slit 26 on the radially opposite side to the first slit 22. Therefore, in the first yoke 17 in this example, the rigidity of the portion of the base 20 on the radially opposite side to the first slit 22 is reduced. Therefore, the deformation resistance of the first yoke 17 when the bolt 24 is tightened is reduced.

[0135] In this embodiment, the first yoke 17 has an outer diameter D 20 Axial dimension L of the base 20 20 The ratio is small, about 1.2, and the central axis O of the mounting holes 23a, 23b, which is the tightening center, is 23 Therefore, the deflection rigidity of the base 20 is high, and therefore the effect of reducing the deformation resistance by forming the second slits 26 is large.

[0136] In the first yoke 17 of this example, the deformation resistance when the bolts 24 are tightened is reduced, and therefore the tightening force of the base 20 is sufficiently ensured. Therefore, even when the first yoke 17 of this example is incorporated into a column-assist steering device 1 to which not only the torque caused by the driver operating the steering wheel 2 but also high assist torque from the electric assist device 9 is transmitted, micro-sliding of the pinion shaft 13 relative to the base 20 is suppressed. This makes it possible to suppress the progression of damage such as fretting wear and fretting corrosion to the female serration teeth 27 and / or the male serration teeth 28.

[0137] The base 20 of the first yoke 17 in this example has a second slit 26, which is not a partial cylindrical notch but has a width dimension smaller than its length dimension, on the radially opposite side to the first slit 22. This allows the female serration teeth 27 on both circumferential sides of the second slit 26 to be serrated-engaged with the male serration teeth 28 of the pinion shaft 13, ensuring a larger engagement area between the base 20 and the pinion shaft 13 than when a partial cylindrical notch is formed. Therefore, the first yoke 17 in this example can transmit high torque.

[0138] In this embodiment, the first yoke 17 is aligned with the central axis O of the mounting holes 23a, 23b, which are the tightening center of the bolt 24. 23 The central axis O of the insertion hole 25 25 Since the first slits 22 and the second slits 26 are disposed at a twisted position relative to the base 20, a gap is unlikely to remain between the portion of the inner peripheral surface of the base 20 near the first slits 22 and the second slits 26 and the outer peripheral surface of the pinion shaft 13 when the bolts 24 are tightened. Therefore, even when transmitting high torque, the end of the pinion shaft 13 is unlikely to tilt relative to the base 20, so that wear and damage are unlikely to occur to the female serration teeth 27 and the male serration teeth 28. Therefore, the first yoke 17 of the present example is suitable for transmitting high torque.

[0139] In this embodiment, the first yoke 17 has a length L of the second slit 26. 26 The length dimension L of the first slit 22 22 Shorter than (L 26 <L 22 For this reason, the length dimension L of the second slit 26 26 The length dimension L of the first slit 22 22 In comparison with the case where the same is true for the above, when bolt 24 is tightened, stress is prevented from concentrating near second closed end 32 of second slit 26, and yield deformation is prevented near second closed end 32. Therefore, a sufficient tightening force for base 20 is ensured.

[0140] Furthermore, in this example, at least a part of the second closed end 32 of the second slit 26 is aligned with the central axis O of the mounting holes 23a, 23b, which is the fastening center. 23Since the second closed end 32 of the second slit 26 is disposed on the other axial side of the mounting holes 23a, 23b, the entire second closed end 32 of the second slit 26 is aligned with the central axis O 23 In comparison with the case where the second closed end 32 is disposed on one axial side of the first closed end 32, stress concentration in the vicinity of the second closed end 32 is suppressed, and yield deformation in the vicinity of the second closed end 32 is suppressed.

[0141] As described above, according to the first yoke 17 of this embodiment, it is possible to reduce the deformation resistance when the bolt 24 is tightened, and also possible to transmit high torque.

[0142] In the first yoke 17 of the present embodiment, the first closed end 30 of the first slit 22 and the second closed end 32 of the second slit 26 are disposed on the same imaginary cylindrical surface, so that the first slit 22 and the second slit 26 can be machined at once using a common cutter 34. This makes it possible to prevent an increase in the number of steps and therefore an increase in the processing cost of the first yoke 17.

[0143] The first yoke 17 of this example has a toothless portion 29 in a range that circumferentially spans the first slit 22 on the inner peripheral surface of the insertion hole 25, so that the female serration teeth 27 are strongly pressed against the male serration teeth 28 in the first direction when the bolt 24 is tightened. This is therefore advantageous in terms of transmitting high torque.

[0144] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to FIGS.

[0145] In the first yoke 17a of this example, the axial dimension of the base 20a is larger than the axial dimension of the base 20 of the first example. 20 Axial dimension L of base portion 20a 20 Ratio (L 20 / D 20 ) is approximately 2.2.

[0146] The second closed end 32 of the second slit 26 is disposed on the other axial side of the first closed end 30 of the first slit 22. At least a portion of the second closed end 32 of the second slit 26 is aligned with the central axis O of the mounting holes 23a, 23b. 23 Specifically, in this embodiment, the radially outer half of the second closed end 32 is disposed on the other axial side of the central axis O of the mounting holes 23a, 23b. 23 The radially inner half of the second closed end 32 is disposed on the other axial side of the central axis O of the mounting holes 23a, 23b. 23 It is disposed on one axial side of the

[0147] In this embodiment, the first yoke 17a has an outer diameter D 20 Axial dimension L of base portion 20a 20 is approximately 2.2, which is larger than the ratio of the first yoke 17 of the first example (approximately 1.2), so the flexural rigidity of the base 20a is lower than that of the base 20 of the first example. However, since the formation of the second slits 26 reduces the deformation resistance of the base 20a, the fastening force of the base 20a is sufficiently ensured.

[0148] The other configurations and effects of the second example are the same as those of the first example.

[0149] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to FIGS.

[0150] In the first yoke 17b of this embodiment, the pair of flange portions 21c, 21d are separate from the base portion 20b.

[0151] In this example, a pair of flange portions 21c, 21d are provided on a part of a fastening member 39.

[0152] The fastening member 39 has a partially cut cylindrical shape as a whole, and has an end face shape that is substantially U-shaped. The fastening member 39 has a pair of flange portions 21c, 21d and a connecting tube portion .

[0153] The connecting cylinder portion 40 has a semi-cylindrical shape and connects the pair of flange portions 21c, 21d.

[0154] The fastening member 39 has a fitting hole 41 in a portion surrounded by the pair of flange portions 21c, 21d and the connecting tube portion .

[0155] The fastening member 39 is attached to the base portion 20b by inserting the other axial end of the base portion 20b into the fitting hole 41.

[0156] In the first yoke 17b of the present embodiment, the pair of flange portions 21c, 21d are formed separately from the base portion 20b, so that the manufacturing process of the first yoke 17b can be simplified, and therefore the manufacturing cost of the first yoke 17b can be reduced.

[0157] The other configurations and effects of the third example are the same as those of the first example.

[0158] [Example 4] A fourth embodiment of the present disclosure will be described with reference to FIGS.

[0159] This example is an example in which a clamp device according to one aspect of the present disclosure is applied to a connecting device that constitutes an intermediate shaft incorporated in a steering device for an automobile.

[0160] The intermediate shaft 6a of this example constitutes a steering device for a large automobile, and connects the steering shaft and the pinion shaft of a steering gear unit so as to be capable of transmitting torque.

[0161] The intermediate shaft 6 a includes a first shaft 42 , a second shaft 43 , and a coupling device 44 .

[0162] The first shaft 42 is a collapsible shaft, and is configured such that its overall length can be contracted only when an automobile crash occurs and an impact load of a predetermined value or greater is applied to it.

[0163] The second shaft 43 is configured such that its entire length is extendable even in a steady state in which no collision accident has occurred to the automobile.

[0164] The first shaft 42 and the second shaft 43 are two rotating shafts that are arranged coaxially and rotate by operating the steering wheel 2 (see FIG. 1).

[0165] The coupling device 44 connects an end of the first shaft 42 and an end of the second shaft 43 in a torque transmissible manner.

[0166] The coupling device 44 has a base 20 and a pair of flange portions 21a, 21b. Unlike the first yoke 17 of the first example, the coupling device 44 of this example does not have a coupling portion. The coupling device 44 of this example has the same configuration as the first yoke 17 of the first example, except that it does not have a pair of arm portions.

[0167] In this example, one axial end of the second shaft 43 is inserted into the inside of an insertion hole 25 (see FIG. 8) provided in the base 20. As a result, the female serration teeth 27 provided on the inner peripheral surface of the base 20 and the male serration teeth 28 provided on the outer peripheral surface of the end of the second shaft 43 are engaged with each other through serrations.

[0168] The other axial end of the first shaft 42 is fitted onto one axial end of the base 20. The one axial end of the base 20 and the other axial end of the first shaft 42 are fixed by welding with a weld bead portion 45.

[0169] The base 20 of the connecting device 44 of this example has the second slit 26 on the radially opposite side to the first slit 22. Therefore, according to the connecting device 44 of this example, it is possible to reduce the deformation resistance when the bolt 24 (see FIG. 3) is tightened, and to transmit high torque.

[0170] The other configurations and effects of the fourth example are the same as those of the first example.

[0171] Although the first to fourth examples of the embodiment of the present disclosure have been described above, the structures of the first to fourth examples can be appropriately combined and implemented as long as no contradiction occurs. [Explanation of symbols]

[0172] 1 Steering device 2 Steering wheel 3 Steering shaft 4. Steering column 5a, 5b Universal joint 6, 6a Intermediate shaft 7 Steering gear unit 8 Tie Rod 9 Electrically assisted devices 10 Gear housing 11 Torsion bar 12 Output shaft 13 Pinion shaft 14 Torque Sensor 15 Electric motor 16 Worm reducer 17, 17a, 17b First York 18 Second York 19 Cross axis 20, 20a, 20b base 21a, 21b, 21c, 21d flange parts 22 First Slit 23a, 23b Mounting holes 24 Volts 25 Insertion hole 26 Second Slit 27 Female serrated teeth 28 Male serrated teeth 29 Missing tooth area 30 1st closed end 31 1st open end 32 Second closed end 33 2nd open end 34 Cutter 35 Gap 36 Connecting part 37a, 37b Arm section 38 Through hole 39 Fastening members 40 Connecting cylinder part 41 Fitting hole 42 1st Shaft 43 Second Shaft 44 Coupling device 45 Weld bead 46 Overhang tube part 100a, 100b York 101a, 101b base 102a, 102b First slit

Claims

1. The device includes a cylindrical base and a pair of flanges. the base portion has an insertion hole extending in the axial direction, a first slit disposed at one location in the circumferential direction and extending in the axial direction, the first slit having an end on one axial side which is a first closed end and an end on the other axial side which is a first open end, and a second slit disposed on the opposite side in the radial direction to the first slit and extending in the axial direction, the second slit having an end on one axial side which is a second closed end and an end on the other axial side which is a second open end, The pair of flange portions have mounting holes on the same axis and are disposed on both sides of the first slit in the circumferential direction, the central axes of the pair of mounting holes are disposed at skewed positions with respect to the central axis of the insertion hole, The second closed end of the second slit is disposed on the other axial side of the first closed end of the first slit. Clamping device.

2. 2. The clamp device according to claim 1, wherein the first closed end of the first slit is disposed on one side in the axial direction relative to a central axis of the pair of mounting holes.

3. 3. The clamp device according to claim 2, wherein at least a portion of the second closed end of the second slit is located on the other axial side of the central axis of the pair of mounting holes.

4. 2. The clamping device according to claim 1, wherein the first closed end of the first slit and the second closed end of the second slit are formed by concave cylindrical surfaces and are disposed on the same imaginary cylindrical surface.

5. The clamping device of claim 1 , wherein the insertion hole has a non-circular cross-sectional shape.

6. 6. The clamping device according to claim 5, wherein the base portion has female serration teeth on an inner peripheral surface thereof.

7. 2. The clamping apparatus of claim 1, wherein said pair of flanges are integral with said base.

8. The clamp device according to claim 1 , further comprising a connecting portion that is connected to another member in a torque-transmittable manner.

9. The clamp device according to claim 8 , wherein the connecting portion is constituted by a pair of arms.

10. A clamping device as described in claim 9, wherein one of the pair of arm portions is positioned at a position where its phase in the circumferential direction coincides with the first slit, and the other of the pair of arm portions is positioned at a position where its phase in the circumferential direction coincides with the second slit.

11. A method for manufacturing the clamp device according to claim 4, comprising the steps of: A method for manufacturing a clamp device, comprising machining the first slit and the second slit at once using a common cutter.

12. Two rotational axes that rotate by operating the steering wheel and are not arranged on the same axis; a universal joint that connects the ends of the two rotating shafts to each other in a torque transmittable manner, The universal joint has a pair of yokes and a cross shaft, At least one of the pair of yokes is the clamp device according to claim 9 or 10. Steering gear.

13. Two coaxially arranged rotating shafts that rotate by operating a steering wheel; A coupling device that connects the ends of the two rotating shafts to each other in a torque-transmittable manner, The connecting device is a clamping device according to any one of claims 1 to 8. Steering gear.

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