Clamp device, method of manufacturing the clamp device, and steering device

Abstract

To provide a clamp device which can be reduced in deformation resistance during fastening of a bolt and can mitigate stress occurring during the fastening of the bolt.SOLUTION: The clamp device includes a cylindrical base 20, and a pair of flange portions 21a, 21b. The base 20 has: an axially extending through-hole: an axially extending slit 22 arranged at one position in a circumferential direction; and a through-hole 26 arranged on the opposite side of the slit 22 with respect to the radial direction and having a circular opening shape passing therethrough in the radial direction. The slit 22 is comprised of: a wide hole portion 32 arranged in the end on one axial side and having a circular opening shape; and a narrow portion 33 arranged adjacent to the other axial side of the wide hole portion 32 and opened to the end face on the other axial side of the base 20. The wide hole portion 32 is wider than the narrow portion 33 and arranged coaxially with the through-hole 26.SELECTED DRAWING: Figure 7

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 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 are provided on both sides of the slit in the circumferential direction. The pair of flanges have 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 difference in the structure of the slits 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. 27 shows an example of a conventional structure of an open-slit type yoke 100a, while Fig. 28 shows an example of a conventional structure of a closed-slit type yoke 100b.

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

[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] Furthermore, in the closed slit type yoke 100b, stress may be concentrated in the vicinity of the closed end of the slit 102b in the base 101b when the bolt is tightened, which may cause damage such as cracks.

[0015] In view of these circumstances, techniques have been devised for closed slit type yokes that reduce the deformation resistance when the bolt is tightened and that alleviate the stress generated when the bolt is tightened.

[0016] Japanese Patent Application Laid-Open No. 2009-299706 describes a technique in which the closed end of the slit is configured with a partial cylindrical surface to reduce stress generated in the yoke.

[0017] JP 2018-128077 A describes a technology for reducing deformation resistance when tightening a bolt by forming an auxiliary slit of the same shape as the slit in a part of the base that is located radially opposite the slit. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] JP 2009-299706 A [Patent Document 2] JP 2018-128077 A Summary of the Invention [Problem to be solved by the invention]

[0019] The yoke of the conventional structure described in JP 2009-299706 A can alleviate the stress generated when the bolt is tightened, but cannot reduce the deformation resistance when the bolt is tightened.

[0020] The yoke of the conventional structure described in JP 2018-128077 A can reduce the deformation resistance when the bolt is tightened, but cannot alleviate the stress generated when the bolt is tightened.

[0021] The yoke of the conventional structure described in JP 2018-128077 A has a slit and an auxiliary slit at two positions on the radially opposite side of the base, and these slits and auxiliary slits open on the axial end face of the base. Therefore, the rigidity of the part of the base where the slit and auxiliary slit are formed is likely to be insufficient. In addition, even when the bolt is tightened, gaps are likely to remain between the inner peripheral surface of the base and the outer peripheral surface of the shaft part in the vicinity of each of the slit and auxiliary slit. Therefore, the end of the rotating shaft is likely to tilt around the central axis of the bolt, and damage such as fretting wear and fretting corrosion is likely to occur to the female serration teeth present in the vicinity of each of the slit and auxiliary slit.

[0022] 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.

[0023] An object of the present disclosure is to provide a clamp device that can reduce deformation resistance when a bolt is tightened and can alleviate stress that occurs when the bolt is tightened. [Means for solving the problem]

[0024] A clamp device according to one aspect of the present disclosure includes a cylindrical base and a pair of flanges.

[0025] The base has an insertion hole extending in the axial direction, a slit arranged in one circumferential direction and extending in the axial direction, and a through hole arranged on the opposite side of the slit in the radial direction and having a circular opening shape that penetrates in the radial direction.

[0026] The slit consists of a wide hole portion having a circular opening shape located at the end on one axial side, and a narrow hole portion located adjacent to the other axial side of the wide hole portion and opening at the end face on the other axial side of the base.

[0027] The wide hole portion has a width dimension larger than that of the narrow hole portion and is disposed coaxially with the through hole.

[0028] The pair of flange portions have coaxial mounting holes and are disposed on both sides of the narrow portion in the circumferential direction.

[0029] In the clamp device according to one aspect of the present disclosure, the inner diameter of the through hole is equal to the inner diameter of the wide hole portion.

[0030] In the clamp device according to one aspect of the present disclosure, the inner diameter of the through hole is different from the inner diameter of the wide hole portion.

[0031] In this case, the inner diameter of the through hole can be larger than the inner diameter of the wide hole portion, or the inner diameter of the through hole can be smaller than the inner diameter of the wide hole portion.

[0032] In the clamp device according to one aspect of the present disclosure, the through hole and the wide hole portion are cylindrical holes.

[0033] In the clamp device according to one aspect of the present disclosure, the through hole and the wide hole portion are tapered holes.

[0034] In the clamp device according to one aspect of the present disclosure, the insertion hole has a non-circular cross-sectional shape.

[0035] 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.

[0036] In the clamp device according to one aspect of the present disclosure, the pair of flange portions are integral with the base portion.

[0037] Alternatively, the pair of flange portions may be separate from the base portion.

[0038] 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.

[0039] 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.

[0040] 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 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 through hole.

[0041] 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.

[0042] In the method for manufacturing the clamp device according to the aspect of the present disclosure, the through hole and the wide hole portion are machined at one time using a common drilling tool, i.e., the through hole and the wide hole portion are formed by simultaneous machining.

[0043] A steering device according to one embodiment of the present disclosure includes two rotating shafts that are not arranged on the same axis and that rotate by operating a steering wheel, and a universal joint that connects the ends of the two rotating shafts to each other so as to transmit torque.

[0044] The universal joint includes a pair of yokes and a cross shaft.

[0045] In the clamp device according to the above aspect, at least one of the pair of yokes has the pair of arm portions.

[0046] 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.

[0047] 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

[0048] According to a clamp device according to an aspect of the present disclosure, it is possible to reduce the deformation resistance when the bolt is tightened, and to alleviate the stress generated when the bolt is tightened. [Brief description of the drawings]

[0049] [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 through hole and an enlarged hole portion in the first yoke by using a common drilling tool. [Figure 16] FIG. 16 is a diagram corresponding to FIG. 10 and relating to a second example of the embodiment of the present disclosure. [Figure 17] FIG. 17 is a diagram corresponding to FIG. 15 and relating to a second example of the embodiment of the present disclosure. [Figure 18] FIG. 18 is a diagram corresponding to FIG. 10 and relating to a third example of the embodiment of the present disclosure. [Figure 19] FIG. 19 is a diagram corresponding to FIG. 15 and relating to a third example of the embodiment of the present disclosure. [Figure 20] FIG. 20 is a diagram corresponding to FIG. 4 and relating to a fourth example of an embodiment of the present disclosure. [Figure 21] FIG. 21 is a diagram corresponding to FIG. 8 and relating to the fourth example. [Figure 22] FIG. 22 is a side view showing an intermediate shaft constituting a steering device according to a fifth example of an embodiment of the present disclosure. [Diagram 23] FIG. 23 is a diagram corresponding to FIG. 4 and relating to the fifth example. [Figure 24] FIG. 24 is a diagram corresponding to FIG. 7 and relating to the fifth example. [Diagram 25] FIG. 25 is a diagram corresponding to FIG. 6 for a reference example of the present disclosure. [Figure 26] FIG. 26 is a diagram corresponding to FIG. 11 and relating to a reference example of the present disclosure. [Figure 27] FIG. 27 is a perspective view showing an example of a conventional structure of an open slit type yoke. [Figure 28] FIG. 28 is a perspective view showing an example of a conventional structure of a closed slit type yoke. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 15. FIG.

[0051] 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.

[0052] [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.

[0053] 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.

[0054] 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.

[0055] The longitudinal direction refers to the longitudinal direction of the vehicle in which the steering device is mounted.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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 enabling torque transmission.

[0061] 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.

[0062] 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.

[0063] The first yoke 17 will be described below with reference to FIGS.

[0064] [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.

[0065] The base 20 has a 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 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.

[0066] 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.

[0067] A slit is a narrow gap whose width is smaller than its length.

[0068] The first yoke 17 is made of a metal material by subjecting it to, for example, forging and cutting processes.

[0069] In this example, the tubular shape of the base 20 is specifically a substantially cylindrical shape.

[0070] The base 20 has an insertion hole 25, a slit 22, and a through hole .

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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 that circumferentially straddles the slit 22 on the inner peripheral surface of the base portion 20. 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.

[0075] 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.

[0076] 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.

[0077] The female serration teeth 27 and the toothless portion 29 are formed, for example, by broaching using a broach tool.

[0078] The 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 slit 22 coincides with the axial direction, the width direction of the slit 22 coincides with the first direction, and the depth direction of the slit 22 coincides with the second direction.

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

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

[0081] An end of the slit 22 on one axial side is a closed end 30 that is closed in the axial direction, and an end of the slit 22 on the other axial side is an open end 31 that is open in the axial direction. In other words, the slit 22 does not open on the end face of the base 20 on one axial side, but opens on the end face of the base 20 on the other axial side.

[0082] The slit 22 comprises a wide hole portion 32 and a narrow portion 33 .

[0083] The wide hole portion 32 and the narrow hole portion 33 have different width dimensions and communicate with each other in the axial direction.

[0084] The wide hole portion 32 is disposed at one axial end of the slit 22 and is located at the axial middle portion of the base portion 20 .

[0085] The wide hole portion 32 has a circular opening shape when viewed from the second direction. Therefore, the closed end 30 of the slit 22 is formed by a concave curved surface. 32 is oriented in the second direction, and the central axis O of the insertion hole 25 is 25 is perpendicular to

[0086] In this example, the wide hole portion 32 has an inner diameter d 32Therefore, the closed end 30 of the slit 22 is formed by a partial cylindrical surface.

[0087] However, when implementing the present disclosure, the wide hole portion may be a tapered hole whose inner diameter changes in the second direction, in which case the closed end of the slit is formed by a tapered surface.

[0088] The wide hole portion 32 has a width dimension W 33 Width dimension W larger than 32 (W 32 >W 33 ).

[0089] Width dimension W of narrow portion 33 33 Width dimension W of the wide hole portion 32 32 Ratio (W 32 / W 33 ) is not particularly limited, but may be, for example, 1.5 or more and 6 or less, and preferably 3 or more and 5 or less. In this example, the width dimension W 33 Width dimension W of the wide hole portion 32 32 Ratio (W 33 / W 32 ) is approximately 4.5.

[0090] The wide hole portion 32 is formed, for example, by cutting using a drill or other such boring tool.

[0091] The narrow width portion 33 is disposed adjacent to the other axial side of the wide hole portion 32, and is provided in a range extending from the end portion on the other axial side of the slit 22 to the portion on one axial side.

[0092] The narrow width portion 33 opens into the end face on the other axial side of the base portion 20. Therefore, the end portion on the other axial side of the narrow width portion 33 forms an open end 31 that is open in the axial direction.

[0093] The narrow portion 33 extends linearly in the axial direction. 33 is the central axis O of the insertion hole 25 25 are arranged approximately parallel to each other.

[0094] Central axis O of narrow portion 33 33 is the central axis O of the wide hole portion 32. 32 Therefore, the slit 22 is perpendicular to the central axis O of the insertion hole 25. 25 and the central axis O of the narrow portion 33 33 The shape is symmetric with respect to a virtual plane β that includes

[0095] The narrow width portion 33 has a rectangular opening shape that is long in the axial direction when viewed from the second direction.

[0096] Width dimension W of narrow portion 33 33 is constant over the entire length of the narrow portion 33 before the bolt 24 is tightened. However, the width dimension of the narrow portion 33 may be varied depending on the axial position of the narrow portion 33.

[0097] The narrow portion 33 is formed, for example, by cutting using a cutter, which is a rotary cutting tool.

[0098] The through hole 26 is disposed on the radially opposite side of the base 20 from the slit 22 and penetrates the base 20 in the radial direction.

[0099] In this example, the through holes 26 are disposed at positions that are out of phase with the slits 22 by 180 degrees in the circumferential direction.

[0100] The through hole 26 has a circular opening shape when viewed from the second direction. 26 is oriented in the second direction, and the central axis O of the insertion hole 25 is 25 is perpendicular to

[0101] In this example, the through hole 26 has an inner diameter d 26 It is a cylindrical hole where the

[0102] However, when implementing the present disclosure, the through hole may be a tapered hole whose inner diameter changes in the second direction.

[0103] In this example, the inner diameter d of the through hole 26 26 is the inner diameter d of the wide hole portion 32 32 is equal to (d 26 =d 32 ).

[0104] The wide hole portion 32 is disposed coaxially with the through hole 26. That is, the wide hole portion 32 is disposed coaxially with the central axis O of the through hole 26. 26 and the central axis O of the wide hole portion 32 32 It is consistent with that.

[0105] The through-holes 26 are formed, for example, by cutting using a boring tool such as a drill.

[0106] In this example, the inner diameter d of the through hole 26 26 and the inner diameter d of the wide hole portion 32 32 Since these are equal to each other, the through hole 26 and the wide hole portion 32 can be machined using a common drilling tool.

[0107] When the through hole 26 and the wide hole portion 32 are machined using a common drilling tool, the through hole 26 and the wide hole portion 32 can be machined at once (one-pass machining) using the common drilling tool. In other words, the through hole 26 and the wide hole portion 32 can be formed by simultaneous machining by reciprocating the common drilling tool only once in the second direction.

[0108] Specifically, the central axis O of the drilling tool 34 34is placed on the virtual plane β and faces the second direction. Then, as shown in FIG. 15, the drilling tool 34 is moved in the direction of the arrow X while rotating to machine the through hole 26 from the outer peripheral surface side of the base 20, and then the wide hole portion 32 is machined from the inner peripheral surface side of the base 20. Then, the drilling tool 34 is withdrawn in the direction opposite to the direction of the arrow X. Alternatively, the drilling tool 34 is moved in the direction of the arrow Y while rotating to machine the wide hole portion 32 from the outer peripheral surface side of the base 20, and then the through hole 26 is machined from the inner peripheral surface side of the base 20. Then, the drilling tool 34 is withdrawn in the direction opposite to the direction of the arrow Y. In either case, the drilling tool 34 is reciprocated once in the second direction to machine the through hole 26 and the wide hole portion 32.

[0109] However, when implementing the present disclosure, the through hole and the wide hole portion can be machined separately using different drilling tools, or can be machined separately using a common tool.

[0110] The pair of flange portions 21a, 21b are disposed on both sides of the narrow portion 33 of the slit 22 in the circumferential direction. Therefore, the pair of flange portions 21a, 21b are disposed on the other axial side of the wide hole portion 32.

[0111] 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 a second direction from a portion of the outer peripheral surface of the base portion 20 that is located on both sides of the slit 22 in the circumferential direction. Each of the pair of flange portions 21a, 21b has a plate shape.

[0112] In this example, the pair of flange portions 21a, 21b have a substantially oval side shape when viewed from the first direction.

[0113] In this example, the pair of flange portions 21 a, 21 b are integral with the base portion 20 .

[0114] 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 narrow portion 33 of the slit 22 in the second direction. The gap 35 has the same size as the width dimension of the narrow portion 33 before the bolt 24 is tightened. The gap 35 can be formed by cutting the narrow portion 33 at the same time as the narrow portion 33 using a cutter, which is a rotary cutting tool.

[0115] The dimension between the outer surfaces of the pair of flange portions 21a, 21b in the first direction is substantially the same as the outer diameter of the base portion 20 before the bolts 24 are tightened.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] The first yoke 17 further includes a connecting portion 36 for connecting to another member in a manner enabling torque transmission.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] Of the pair of arm portions 37a, 37b, the phase of one arm portion 37a in the circumferential direction matches the phase of the slit 22 in the circumferential direction, and the phase of the other arm portion 37b in the circumferential direction matches the phase of the through hole 26 in the circumferential direction.

[0125] In this example, the pair of arm portions 37 a and 37 b are integrally formed with the base portion 20 .

[0126] 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.

[0127] 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 slit 22 and the gap 35, and the diameter of the base portion 20 is reduced, and the end of the pinion shaft 13 is tightened by the base portion 20. In this way, the first yoke 17 is fixed 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.

[0128] According to the first yoke 17 of the present embodiment, the deformation resistance when the bolt 24 is tightened can be reduced, and the stress generated when the bolt 24 is tightened can be alleviated.

[0129] The base 20 of the first yoke 17 in this example has a through hole 26 penetrating in the radial direction on the radial opposite side of the slit 22. Therefore, in the first yoke 17 in this example, the rigidity of the portion of the base 20 on the radial opposite side of the slit 22 is reduced. Therefore, the deformation resistance of the first yoke 17 when the bolt 24 is tightened is reduced.

[0130] Slit 22 has wide hole portion 32 with a circular opening shape at one axial end. Therefore, closed end 30 of slit 22 is formed with a concave curved surface. Therefore, according to first yoke 17 of the present example, stress is less likely to concentrate in the vicinity of closed end 30 of slit 22, and therefore stress generated when bolt 24 is tightened is mitigated.

[0131] As described above, according to the first yoke 17 of the present embodiment, the deformation resistance when the bolt 24 is tightened can be reduced, and the stress generated when the bolt 24 is tightened can be alleviated.

[0132] 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.

[0133] In the first yoke 17 of this embodiment, the stress generated in the base 20 when the bolt 24 is tightened is alleviated, so that the occurrence of damage such as cracks in the base 20 is prevented.

[0134] The first yoke 17 of this example has a through hole 26 that is closed in the axial direction on the radially opposite side of the base 20 from the slit 22, rather than an auxiliary slit that opens on the end face on the other axial side of the base 20. This ensures the rigidity of the base 20 compared to when an auxiliary slit is formed. This makes it possible to prevent the end of the pinion shaft 13 from tilting with respect to the base 20, and to prevent damage such as fretting wear and fretting corrosion from occurring to the female serration teeth 27 and / or the male serration teeth 28.

[0135] In the first yoke 17 of the present embodiment, the through hole 26 and the wide hole portion 32 are arranged coaxially, so that the through hole 26 and the wide hole portion 32 can be machined at once using a common drilling tool 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.

[0136] The first yoke 17 of this example has a toothless portion 29 in a range that circumferentially spans the 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.

[0137] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to FIGS.

[0138] In the first yoke 17a of this embodiment, the inner diameter d 26 However, the inner diameter d of the through hole 26a is larger than that of the first example. 26 is the inner diameter d of the wide hole portion 32 of the slit 22 32 Different from (d 26 ≠d 32 Specifically, the inner diameter d of the through hole 26a 26 is the inner diameter d of the wide hole portion 32 32 greater than (d 26 >d 32 ).

[0139] In this embodiment, the through hole 26a and the wide hole portion 32 are arranged coaxially. The through hole 26a has an inner diameter d 26 The wide hole portion 32 has an inner diameter d 32 It is a cylindrical hole where the

[0140] In this example, the inner diameter d of the through hole 26a 26 and the inner diameter d of the wide hole portion 32 32 Since the diameter of the hole 32 is different from the diameter of the hole 32, a stepped drill as shown in FIG. 32 and the inner diameter d of the through hole 26a on the base end side. 26 The shaft has a large diameter portion 48 having an outer diameter equal to that of the shaft.

[0141] In order to drill the through hole 26a and the wide hole portion 32, the central axis O of the drilling tool 34a is 34 , the central axis O of the insertion hole 25 25 and the central axis O of the narrow portion 33 33and facing the second direction. Then, the drilling tool 34a is moved in the direction of the arrow X while rotating. As a result, first, the small diameter shaft portion 47 on the tip side of the drilling tool 34a processes the pilot hole of the through hole 26a from the outer circumferential surface side of the base 20. Then, the small diameter shaft portion 47 on the tip side of the drilling tool 34a processes the wide hole portion 32 from the inner circumferential surface side of the base 20, and at the same time, the large diameter shaft portion 48 on the base end side of the drilling tool 34a widens the inner diameter of the pilot hole to process the through hole 26a. Then, the drilling tool 34a is retreated in the direction opposite to the arrow X direction.

[0142] In this example, the rigidity of the portion of the base 20 opposite the slit 22 in the radial direction is further reduced compared to the structure of Example 1. Therefore, the deformation resistance of the first yoke 17a when the bolt 24 is tightened is further reduced.

[0143] The other configurations and effects of the second example are the same as those of the first example.

[0144] When carrying out the present disclosure, as a modified example of the second example, the inner diameter of the through hole can be made smaller than the inner diameter of the wide hole portion. In this case, a step drill is used to machine a pilot hole for the wide hole portion from the outer peripheral surface side of the base portion using a small diameter shaft portion at the tip end. Then, the small diameter shaft portion at the tip end of the drilling tool machines a through hole from the inner peripheral surface side of the base portion, and at the same time, the large diameter shaft portion at the base end of the drilling tool widens the inner diameter of the pilot hole to machine the wide hole portion.

[0145] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to FIGS.

[0146] In the first yoke 17b of this example, similar to the structure of the second example, the inner diameter of the through hole 26b is larger than the inner diameter of the wide hole portion 32a. Furthermore, the through hole 26b and the wide hole portion 32a are arranged coaxially.

[0147] In this example, the wide hole portion 32a is configured as a tapered hole whose inner diameter changes in the second direction. The inner diameter of the wide hole portion 32a increases from the outer circumferential surface side of the base portion 20 toward the inner circumferential surface side.

[0148] The through hole 26b is configured as a tapered hole whose inner diameter changes in the second direction. The inner diameter of the through hole 26b becomes smaller from the outer circumferential surface side of the base 20 toward the inner circumferential surface side.

[0149] In this example, the inner diameter of through hole 26b and the inner diameter of wide hole portion 32a are different, and through hole 26b and wide hole portion 32a are tapered holes, so that a tapered drill as shown in Fig. 19 can be used as drilling tool 34b. The outer diameter of drilling tool 34b increases from the tip side to the base end side.

[0150] In order to drill the through hole 26b and the wide hole portion 32a, the central axis O of the drilling tool 34b is 34 , the central axis O of the insertion hole 25 25 and the central axis O of the narrow portion 33 33 and facing the second direction. Then, the drilling tool 34b is moved in the direction of the arrow X while being rotated. As a result, the tip portion of the drilling tool 34b machines the wide hole portion 32a from the inner peripheral surface side of the base portion 20, and at the same time, the base portion of the drilling tool 34b machines the through hole 26b from the outer peripheral surface side of the base portion 20. Thereafter, the drilling tool 34b is retreated in the direction opposite to the direction of the arrow X.

[0151] In this example, the rigidity of the portion of the base 20 opposite the slit 22 in the radial direction is further reduced compared to the structure of Example 1. Therefore, the deformation resistance of the first yoke 17b when the bolt 24 is tightened is further reduced.

[0152] The other configurations and effects of the third example are the same as those of the first and second examples.

[0153] When implementing the present disclosure, as a modified example of the third example, the inner diameter of the through hole can be made smaller than the inner diameter of the wide hole portion. In this case, the inner diameter of the through hole can be made larger from the outer peripheral surface side of the base toward the inner peripheral surface side, and the inner diameter of the wide hole portion can be made smaller from the outer peripheral surface side of the base toward the inner peripheral surface side. Then, using a taper drill hole tool, the tip portion of the hole tool can be used to machine the through hole from the inner peripheral surface side of the base, while the base portion of the hole tool can be used to machine the wide hole portion from the outer peripheral surface side of the base.

[0154] [Example 4] A fourth embodiment of the present disclosure will be described with reference to FIGS.

[0155] In the first yoke 17c of this embodiment, the pair of flange portions 21c, 21d are separate from the base portion 20a.

[0156] In this example, a pair of flange portions 21c, 21d are provided on a part of a fastening member 39.

[0157] 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 .

[0158] The connecting cylinder portion 40 has a semi-cylindrical shape and connects the pair of flange portions 21c, 21d.

[0159] 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 .

[0160] The fastening member 39 is attached to the base portion 20a by inserting the other axial end of the base portion 20a into the fitting hole 41.

[0161] In the first yoke 17c of the present embodiment, the pair of flange portions 21c, 21d are formed separately from the base portion 20a, so that the manufacturing process of the first yoke 17c can be simplified, and therefore the manufacturing cost of the first yoke 17c can be reduced.

[0162] The other configurations and effects of the fourth example are the same as those of the first example.

[0163] [Example 5] A fifth example of the embodiment of the present disclosure will be described with reference to FIGS.

[0164] 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.

[0165] 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.

[0166] The intermediate shaft 6 a includes a first shaft 42 , a second shaft 43 , and a coupling device 44 .

[0167] 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.

[0168] The second shaft 43 is configured such that its entire length is extendable even in a steady state in which no automobile collision has occurred.

[0169] 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).

[0170] The coupling device 44 connects an end of the first shaft 42 and an end of the second shaft 43 in a manner enabling torque transmission.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] The base 20 of the connecting device 44 of this example has a through hole 26 on the radially opposite side to the slit 22, and one end on one axial side of the slit 22 is formed by the wide hole portion 32. 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 it is also possible to alleviate the stress generated when the bolt 24 is tightened.

[0175] The other configurations and effects of the fifth example are the same as those of the first example.

[0176] [Reference example] A reference example of the present disclosure will be described with reference to FIGS.

[0177] The first yoke 17x of this reference example has a through hole 26x in a portion of the base 20x that is located on the radially opposite side of the slit 22x. However, the through hole 26x does not have a circular opening shape, but has an elliptical opening shape that is long in the axial direction.

[0178] In this reference example, the slit 22x does not have an enlarged hole portion at one end on the axial direction side, and is composed only of a narrow width portion 33x.

[0179] The base 20x of the first yoke 17x of this reference example has a through hole 26x penetrating in the radial direction on the radial opposite side to the slit 22x, so that the deformation resistance of the first yoke 17x is reduced when the bolt 24 (see FIG. 3) is tightened. However, the slit 22x does not have a wide hole portion having a circular opening shape at one end on one axial side, and has two corner portions 46 at the closed end 30x. For this reason, in the first yoke 17x of the reference example, stress is likely to concentrate near the corner portions 46 of the closed end 30x when the bolt 24 is tightened, which may cause damage such as cracks.

[0180] In the first yoke 17x of this reference example, the through hole 26x has an opening shape that is long in the axial direction, so even if a wide hole portion is provided at one end of the slit 22x in the axial direction, the through hole 26x and the wide hole portion cannot be machined at the same time using a common drilling tool. Therefore, the through hole 26x and the wide hole portion must be machined separately using different tools, which causes an increase in processing costs.

[0181] The first yokes 17, 17a to 17c and the connecting device 44 of the first to fifth examples of the embodiment of the present disclosure can solve the problem of stress concentration that cannot be solved by the first yoke 17x of the present reference example. Also, the through holes 26, 26a, 26b and the wide hole portions 32, 32a can be machined at the same time using the common drilling tools 34, 34a, 34b, thereby reducing the processing cost.

[0182] Although the first to fifth examples of the embodiment of the present disclosure have been described above, the structures of the first to fifth examples can be appropriately combined and implemented as long as no contradiction occurs. [Explanation of symbols]

[0183] 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, 17c, 17x 1st York 18 Second York 19 Cross axis 20, 20a, 20x base 21a, 21b, 21c, 21d flange parts 22, 22x slit 23a, 23b Mounting holes 24 Volts 25 Insertion hole 26, 26a, 26b, 26x through holes 27 Female serrated teeth 28 Male serrated teeth 29 Missing tooth area 30, 30x closed end 31 Open end 32, 32a Wide hole 33, 33x narrow part 34, 34a, 34b Drilling tools 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 Corner 47 Small diameter shaft 48 Large diameter shaft 100a, 100b York 101a, 101b base 102a, 102b Slits

Claims

1. The device includes a cylindrical base and a pair of flanges. the base portion has an insertion hole extending in an axial direction, a slit disposed at one location in a circumferential direction and extending in the axial direction, and a through hole disposed on the opposite side of the slit in a radial direction and having a circular opening shape penetrating in the radial direction, the slit comprises a wide hole portion having a circular opening shape that is located at an end portion on one side in the axial direction, and a narrow hole portion that is located adjacent to the other side of the wide hole portion in the axial direction and that opens into an end face on the other side of the base portion in the axial direction, the wide hole portion has a width dimension larger than that of the narrow hole portion and is disposed coaxially with the through hole, The pair of flange portions have mounting holes on the same axis and are disposed on both sides of the narrow portion in the circumferential direction. Clamping device.

2. 2. The clamping device of claim 1, wherein an inner diameter of the through hole is equal to an inner diameter of the wide hole portion.

3. 2. The clamping device of claim 1, wherein an inner diameter of the through hole is different from an inner diameter of the wide hole portion.

4. 2. The clamping device of claim 1, wherein the through hole and the wide hole are cylindrical holes.

5. The clamping device according to claim 1 , wherein the through hole and the wide hole portion are tapered holes.

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

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

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

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

10. The clamp device according to claim 9 , wherein the connecting portion is constituted by a pair of arm portions.

11. 11. The clamping device according to claim 10, wherein one of the pair of arm portions is positioned at a position where its phase in the circumferential direction coincides with the 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 through hole.

12. A method for manufacturing a clamping device according to any one of claims 1 to 11, comprising the steps of: A method for manufacturing a clamping device, in which the through hole and the wide hole portion are machined at the same time using a common drilling tool.

13. 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 any one of claims 10 to 11. Steering gear.

14. 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 9. Steering gear.

Images