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

Abstract

To provide a clamp device that can reduce deformation resistance in the fastening of a bolt, and can secure the rigidity of ends of a base part on both sides in an axial direction.SOLUTION: A clamp device comprises a cylindrical base part 20 and a pair of flange parts 21a, 21b. The base part 20 includes: an insertion hole 25 extending in an axial direction; a slit 22 formed at a point in a circumferential direction and extending in the axial direction; and recessed grooves 26a to 26d which extend in a direction including a component in the axial direction in a portion of an external peripheral surface that is located off the slit 22 in the circumferential direction, both ends of each of the recessed grooves 26a to 26d being closed ends which are closed in the axial direction. The recessed grooves 26a to 26b each include a bottomed part 32 and a through-part 33 in communication with an insertion hole 25, the through-part 33 being arranged in a portion of the recessed grooves 26a to 26d that overlaps with the pair of flange parts 21a, 21b in the axial direction.SELECTED DRAWING: Figure 4

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. 24 shows an example of a conventional structure of an open-slit type yoke 100a, and Fig. 25 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] 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 Laid-Open No. 2018-128139 describes a technology that reduces deformation resistance when tightening a bolt by forming axially extending grooves at two locations on the outer peripheral surface of the base that are circumferentially shifted by 90 degrees from the slit. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] JP 2018-128139 A Summary of the Invention [Problem to be solved by the invention]

[0017] In a yoke of the conventional structure described in JP 2018-128139 A, two grooves formed in the outer peripheral surface of the base open to end faces on both axial sides of the base.

[0018] For this reason, the thickness of the portions of the ends on both axial sides of the base where the recessed grooves are provided is insufficient, and the strength of the base may be insufficient. In particular, the ends on the side where the pair of flanges are provided are prone to stress concentration when the bolts are tightened, and therefore prone to insufficient strength.

[0019] 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.

[0020] An object of the present disclosure is to provide a clamp device that can reduce deformation resistance when a bolt is tightened and ensure strength at both axial ends of the base. [Means for solving the problem]

[0021] A clamp device according to one aspect of the present disclosure includes a cylindrical base and a pair of flanges.

[0022] The base has an insertion hole extending in the axial direction, a slit located at one location in the circumferential direction and extending in the axial direction, and a groove on the outer circumferential surface at a portion offset from the slit in the circumferential direction, which extends in a direction that includes an axial component and has both ends that are closed in the axial direction.

[0023] The groove has a bottom portion and a through portion communicating with the insertion hole.

[0024] The through portion is provided in a portion of the recessed groove that overlaps with the pair of flange portions in the axial direction.

[0025] The pair of flange portions have coaxial mounting holes and are disposed on both sides of the slit in the circumferential direction.

[0026] In a clamp device according to one aspect of the present disclosure, the groove includes only a component in the axial direction and has a linear shape.

[0027] In a clamp device according to one aspect of the present disclosure, the groove extends in a direction that includes an axial component and a circumferential component.

[0028] When the groove extends in a direction including an axial component and a circumferential component, the groove can extend in a spiral shape obliquely relative to both the axial and circumferential directions.

[0029] When the groove extends spirally obliquely with respect to the axial direction and the circumferential direction, one end of the groove can be positioned on the outer peripheral surface of the base near the end of the slit on one axial side, and the other end can be positioned on the outer peripheral surface of the base near the radially opposite portion of the end of the slit on the other axial side.

[0030] In this case, the end portion of the recessed groove on the one axial direction side can be located on the other axial direction side relative to the end portion of the slit on the one axial direction side. Alternatively, the end portion of the recessed groove on the one axial direction side may be located on the one axial direction side relative to the end portion of the slit on the one axial direction side.

[0031] In the clamp device according to one aspect of the present disclosure, the base portion has a plurality of the recessed grooves. In the clamp device according to the aspect of the present disclosure, the base portion may have only one recessed groove.

[0032] When the base portion has a plurality of the recessed grooves, the plurality of recessed grooves can be disposed symmetrically with respect to an imaginary plane including a central axis of the insertion hole and a central axis of the slit. Alternatively, the plurality of recessed grooves may be disposed asymmetrically with respect to an imaginary plane including the central axis of the insertion hole and the central axis of the slit.

[0033] In a clamp device according to one aspect of the present disclosure, the base has, on its outer circumferential surface, two or more of the grooves on each side of an imaginary plane that includes the central axis of the insertion hole and the central axis of the slit.

[0034] In the clamp device according to one aspect of the present disclosure, the cross-sectional shape of the bottomed portion of the groove with respect to an imaginary plane perpendicular to the central axis of the insertion hole is generally semicircular or generally semielliptical.

[0035] In the clamp device according to one aspect of the present disclosure, the recessed groove is a cast-out groove. Alternatively, the recessed groove may be formed by cutting a groove.

[0036] In the clamp device according to one aspect of the present disclosure, the through portion is provided in a portion of the groove that overlaps with the mounting hole in the axial direction.

[0037] In the clamp device according to one aspect of the present disclosure, the insertion hole has a non-circular cross-sectional shape.

[0038] 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.

[0039] In the clamp device according to one aspect of the present disclosure, the pair of flange portions are integral with the base portion.

[0040] Alternatively, the pair of flange portions may be separate from the base portion.

[0041] 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.

[0042] 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.

[0043] In the clamp device according to one aspect of the present disclosure, one of the pair of arms is disposed at a position where its phase in the circumferential direction coincides with that of the slit.

[0044] 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.

[0045] A method for manufacturing a clamping device according to one aspect of the present disclosure includes a step of hot forging a material to form an intermediate material having the groove on its outer circumferential surface.

[0046] In the above step, the material can be subjected to hot forging using a pair of split dies.

[0047] 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.

[0048] The universal joint includes a pair of yokes and a cross shaft.

[0049] In the clamp device according to the above aspect, at least one of the pair of yokes has the pair of arm portions.

[0050] 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.

[0051] The connecting device is the clamp device according to the aspect not having the connecting portion, or the clamp device according to the one aspect having the connecting portion other than the pair of arm portions. Effect of the Invention

[0052] According to the clamp device according to one aspect of the present disclosure, it is possible to reduce the deformation resistance when the bolt is tightened, and to ensure the strength of the ends on both axial sides of the base. [Brief description of the drawings]

[0053] [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 left side of FIG. [Figure 9] FIG. 9 is an end view of the first yoke of the first example as viewed from the right 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 left side of FIG. [Figure 12] FIG. 12 is a view corresponding to FIG. 4, showing the first yoke of the first example with the end of the pinion shaft inserted therein and with a portion of the base cut away. [Figure 13] FIG. 13 is a view corresponding to FIG. 11, showing the first yoke of the first example with the end of the pinion shaft inserted therein and with a portion of the base cut away. [Figure 14] FIG. 14 is a schematic diagram corresponding to the cross section taken along line CC in FIG. 6 and shown to illustrate the manufacturing method of the first yoke of the first example, in which (A) shows the state before the hot forging process, (B) shows the state after the hot forging process, and (C) shows the state after the cutting process. [Figure 15] FIG. 15 is a cross section corresponding to the line DD in FIG. 6, which is shown to explain the manufacturing method of the first yoke of the first example, in which (A) shows the state before the hot forging process, (B) shows the state after the hot forging process, and (C) shows the state after the cutting process. [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 perspective view of the first yoke of the second example as viewed from the left side of FIG. [Figure 18] FIG. 18 is a perspective view showing the first yoke of the second example rotated 180 degrees about the central axis from the state shown in FIG. [Figure 19] FIG. 19 is a diagram corresponding to FIG. 4 and relating to a third example of the embodiment of the present disclosure. [Figure 20] FIG. 20 is a diagram corresponding to FIG. 8 and relating to the third example. [Figure 21] FIG. 21 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 22] FIG. 22 is a diagram corresponding to FIG. 4 and relating to the fourth example. [Diagram 23] FIG. 23 is a diagram corresponding to FIG. 6 and relating to the fourth example. [Figure 24] FIG. 24 is a perspective view showing an example of a conventional structure of an open slit type yoke. [Diagram 25] FIG. 25 is a perspective view showing an example of a conventional structure of a closed slit type yoke. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 15. FIG.

[0055] 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.

[0056] [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.

[0057] 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.

[0058] 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.

[0059] The front-rear direction refers to the front-rear direction of the vehicle in which the steering device 1 is mounted.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] The first yoke 17 will be described below with reference to FIGS.

[0068] [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.

[0069] 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.

[0070] 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, unless otherwise specified. One axial side refers to the right side in Figs. 3 to 7, 10, and 12, and the other axial side refers to the left side in Figs. 3 to 7, 10, and 12. The front-back direction in Figs. 4, 5, and 10, the up-down direction in Figs. 6 and 7, and the left-right direction in Figs. 8 and 9, which are perpendicular to the axial direction of the base 20, are referred to as a first direction. The up-down direction in Figs. 4, 5, and 10, the front-back direction in Figs. 6 and 7, and the up-down direction in Figs. 8 and 9, which are perpendicular to the axial direction and the first direction of the base 20, are referred to as a second direction.

[0071] A slit is a narrow gap whose width is smaller than its length.

[0072] The first yoke 17 is made of a metal material by subjecting it to, for example, forging and cutting processes.

[0073] In this example, the tubular shape of the base 20 is specifically a substantially cylindrical shape.

[0074] The base portion 20 has an insertion hole 25, a slit 22, and recessed grooves 26a to 26d.

[0075] The insertion hole 25 opens at least on the other axial end face of the base 20 and extends in the axial direction. In this example, the insertion hole 25 passes through the base 20 in the axial direction. Specifically, the insertion hole 25 passes through the radial center of the base 20 in the axial direction. That is, the central axis O of the insertion hole 25 is 25 coincides 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 opens only on the end face on the other axial side of the base.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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 90 degrees.

[0080] 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.

[0081] The female serration teeth 27 and the toothless portion 29 are formed, for example, by broaching using a broach tool.

[0082] 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.

[0083] The 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.

[0084] The slits 22 open on the outer circumferential surface and the inner circumferential surface of the base portion 20 .

[0085] The 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.

[0086] 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. That is, the slit 22 does not open on the end face on one axial side of the base 20, but opens on the end face on the other axial side of the base 20. The closed end 30 is located on one axial side portion of the base 20.

[0087] When viewed from the second direction, the slit 22 has a rectangular opening shape that is long in the axial direction.

[0088] Width dimension W of slit 22 22 is constant over the entire length of the slit 22 before the bolt 24 is tightened. However, the width dimension of the slit may be varied depending on the axial position of the slit.

[0089] The closed end 30 of the slit 22 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, the 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.

[0090] However, when implementing the present disclosure, the closed end of the slit may be formed by a plane perpendicular to the central axis of the insertion hole, or may be formed by a partial cylindrical surface that is approximately semicircular arc shaped when viewed from the second direction.

[0091] The slits 22 are formed, for example, by cutting using a cutter, which is a rotary cutting tool.

[0092] However, when implementing the present disclosure, the slits may be formed by methods other than cutting.

[0093] The recessed grooves 26a to 26d are provided in the outer circumferential surface of the base portion 20 in a portion that is off from the slit 22 in the circumferential direction.

[0094] In this example, the recessed grooves 26a to 26d are provided in a portion of the outer circumferential surface of the base 20 that is offset from the slit 22 in the circumferential direction and offset from the radially opposite portion of the slit 22 in the circumferential direction.

[0095] The base 20 has a plurality of recessed grooves 26a to 26d. In this example, the base 20 has four recessed grooves 26a to 26d.

[0096] However, when implementing the present disclosure, the base may have only one groove, or may have two, three, or five or more grooves.

[0097] In this example, the multiple recessed grooves 26a to 26d have the same configuration except that their positions in the circumferential direction are different.

[0098] However, when implementing the present disclosure, the multiple grooves may differ from each other in configuration, such as extension direction, length dimension (total length), width dimension, depth dimension, and the like.

[0099] The recessed grooves 26a to 26d are aligned with the central axis O of the insertion hole 25 in the first direction. 25 and the central axis O of the slit 22 22 The same number of wires are arranged on both sides of a virtual plane β that includes the wires.

[0100] In this example, the recessed grooves 26a to 26d are arranged in pairs on both sides of the imaginary plane β in the first direction. Specifically, the two recessed grooves 26a, 26b are arranged on one side of the imaginary plane β in the first direction (the left side in FIG. 8), and the two recessed grooves 26c, 26d are arranged on the other side of the imaginary plane β in the first direction (the right side in FIG. 8).

[0101] When implementing the present disclosure, if a total of two grooves are provided on the outer peripheral surface of the base, the two grooves can be arranged one on each side of the imaginary plane β in the first direction.

[0102] However, when implementing the present disclosure, the multiple grooves may be arranged in different numbers on both sides of the imaginary plane β in the first direction. For example, when a total of two grooves are provided on the outer peripheral surface of the base, the two grooves may be arranged on one side or the other side of the imaginary plane β in the first direction. When a total of three grooves are provided on the outer peripheral surface of the base, two grooves may be arranged on one side of the imaginary plane β in the first direction, and one groove may be arranged on the other side of the imaginary plane β in the first direction.

[0103] The multiple recessed grooves 26a to 26d are disposed symmetrically with respect to the imaginary plane β.

[0104] In this example, grooves 26a and 26c are disposed symmetrically with respect to the imaginary plane β, and grooves 26b and 26d are disposed symmetrically with respect to the imaginary plane β. Grooves 26a and 26c are disposed at positions where their phases in the circumferential direction differ by 90 degrees (+90 degrees, -90 degrees) from slit 22. Grooves 26b and 26d are disposed at positions where their phases in the circumferential direction differ by 135 degrees (+135 degrees, -135 degrees) from slit 22.

[0105] However, when implementing the present disclosure, the multiple grooves may be arranged asymmetrically with respect to the virtual plane β. Furthermore, when implementing the present disclosure, the magnitude of the phase shift angle of the grooves relative to the slits is not limited to the structure of this example, and may be changed as appropriate.

[0106] The recessed grooves 26a to 26d extend in a direction that includes an axial component.

[0107] The grooves 26a to 26d each include only an axial component, extend linearly in the axial direction, and have a linear shape. 26 is the central axis O of the slit 22 22 are arranged approximately parallel to each other.

[0108] Each of the recessed grooves 26a to 26d has closed ends on both sides that are closed in the axial direction.

[0109] In this example, the grooves 26a-26d have a linear shape that extends linearly in the axial direction, and therefore the end portions on one axial side and the other axial side are closed ends that are closed in the axial direction. In other words, the end portions on one axial side of the grooves 26a-26d do not open to the end face on one axial side of the base 20, and the end portions on the other axial side of the grooves 26a-26d do not open to the end face on the other axial side of the base 20.

[0110] The recessed grooves 26a to 26d have ends on one side and ends on the other side that are located at different axial positions from each other.

[0111] In this example, one axial end portion of the recessed grooves 26a to 26d is located in a portion of the base 20 closer to one axial direction, and the other axial end portion of the recessed grooves 26a to 26d is located in a portion of the base 20 closer to the other axial direction.

[0112] One axial end of each of the recessed grooves 26a to 26b is located on one axial side of the one axial end (closed end 30) of the slit 22. The other axial end of each of the recessed grooves 26a to 26d is located on the other axial side of the mounting holes 23a, 23b.

[0113] The recessed grooves 26a to 26d each have a bottomed portion 32 and a through portion 33 that communicates with the insertion hole 25.

[0114] The recessed grooves 26a to 26d are open only to the outer circumferential surface of the base 20 at the bottomed portion 32, and are open to the outer circumferential surface and the inner circumferential surface of the base 20 at the through portion 33.

[0115] The through portions 33 are provided in the recessed grooves 26a to 26d at portions that overlap with the pair of flange portions 21a, 21b in the axial direction.

[0116] In this example, the through-holes 33 are provided in the recessed grooves 26a to 26d at portions that overlap in the axial direction with the mounting holes 23a, 23b provided in the pair of flange portions 21a, 21b. In other words, the recessed grooves 26a to 26d have bottomed portions 32 at portions that are axially out of alignment with the mounting holes 23a, 23b.

[0117] The axial dimension of the through portion 33 is approximately the same as the diameter of the mounting holes 23a, 23b. The through portion 33 is disposed at a position where its entire axial direction overlaps with the mounting holes 23a, 23b in the axial direction.

[0118] However, when implementing the present disclosure, the through portion may be disposed at a position where only a portion of the through portion in the axial direction overlaps with a pair of flange portions, preferably with the mounting holes, in the axial direction.

[0119] The grooves 26a-26b have a length dimension L in the axial direction that is greater than a width dimension W in the circumferential direction. In the illustrated example, the length dimension L in the axial direction of the grooves 26a-26d is approximately 7.5 times the width dimension W in the circumferential direction at the openings of the grooves 26a-26d.

[0120] The recessed grooves 26a to 26d each have an elliptical opening shape that is long in the axial direction.

[0121] In this example, the grooves 26a-26d have a circumferential width W that is substantially constant along the axial direction, except for both axial ends. Also, the groove depths of the grooves 26a-26d to the bottomed portions 32 are substantially constant along the axial direction, except for both axial ends.

[0122] However, when implementing the present disclosure, the width dimension and depth dimension of the groove may vary depending on the axial position of the groove. For example, the circumferential width dimension of the groove may be smaller or larger from the other axial side toward the one axial side. Also, the groove depth of the groove may be shallower or deeper from the other axial side toward the one axial side.

[0123] As shown in FIG. 14C, the central axis O of the insertion hole 25 25 With respect to an imaginary plane perpendicular to the plane of the grooves 26a to 26d, the cross-sectional shape of the bottomed portion 32 of each of the grooves 26a to 26d is substantially semicircular (partially circular) or substantially semielliptical.

[0124] However, when implementing the present disclosure, the cross-sectional shape of the groove is not limited to a semicircular shape or a semi-elliptical shape, and other shapes such as a triangular shape, a trapezoidal shape, or a rectangular shape may be adopted.

[0125] The grooves 26a to 26d are cast-out grooves. That is, the grooves 26a to 26d are formed by protrusions 42 provided on the inner peripheral surfaces of the split dies 40a and 40b during hot forging, which will be described later.

[0126] However, when implementing the present disclosure, the grooves may be formed by other processing methods than casting, such as cutting.

[0127] The pair of flange portions 21a, 21b are disposed on both sides of the slit 22 in the circumferential direction.

[0128] 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.

[0129] In this example, the pair of flange portions 21a, 21b have a substantially semicircular side shape when viewed from the first direction.

[0130] In this example, the pair of flange portions 21 a, 21 b are integral with the base portion 20 .

[0131] 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 slit 22 in the second direction. The gap 35 has the same size as the width dimension of the slit 22 before the bolt 24 is tightened. The gap 35 can be formed by cutting the slit 22 at the same time as the gap 35 using a cutter, which is a rotary cutting tool.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] The first yoke 17 further includes a connecting portion 36 for connecting to another member in a manner enabling torque transmission.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] In this example, the pair of arm portions 37 a and 37 b are integrally formed with the base portion 20 .

[0143] 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.

[0144] 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 to increase the width of the recessed grooves 26a to 26d, thereby reducing the diameter of the base portion 20 and tightening the end of the pinion shaft 13 with the base portion 20. In this way, the first yoke 17 is fixed to the end of the pinion shaft 13. In this example, the middle portion of the bolt 24 is engaged with the engagement recessed groove 34 provided on the outer circumferential surface of the pinion shaft 13. This prevents the pinion shaft 13 from coming loose.

[0145] Next, a method for manufacturing the first yoke 17 of this embodiment will be described.

[0146] In this embodiment, the first yoke 17 is produced by subjecting a round bar-shaped material 39 such as S35C, which is carbon steel for machine construction, to hot forging and cutting.

[0147] Specifically, as shown in FIG. 14(A) and FIG. 15(A), a material 39 heated to the austenite region is spun into a pair of split molds 40a and 40b so that the central axis O of the material 39 is aligned along the center axis O of the material 39. 39 14(B) and 15(B), an intermediate material 41 having a rough external shape of the first yoke 17 is obtained.

[0148] A plurality of grooves 26a-26d are formed on the outer circumferential surface of the intermediate material 41 by the protruding strips 42 having a semicircular cross section provided on the inner circumferential surfaces of the split dies 40a, 40b. Therefore, the grooves 26a-26d are cast-out grooves. After the hot forging process, the through-holes 33 of the grooves 26a-26d are incomplete, and deep-hole bottomed portions 52 deeper than the bottomed portions 32 are formed in the portions where the through-holes 33 should be formed.

[0149] The protrusion 42 has a small protrusion 43 and a large protrusion 44 that protrude from the inner surface of the split dies 40a, 40b by different amounts. In this example, as shown in Fig. 14(B), the small protrusion 43 of the protrusion 42 forms the bottomed portion 32 of the grooves 26a to 26d. As shown in Fig. 15(B), the large protrusion 44 of the protrusion 42 forms the deep hole bottomed portion 52 that becomes the through portion 33 of the grooves 26a to 26d.

[0150] The intermediate material 41 is subjected to cutting. Specifically, the mounting holes 23a, 23b are formed by drilling. A pilot hole for the insertion hole 25 is also formed to form the through-hole 33. Then, the pilot hole is broached to form female serration teeth 27 on the inner peripheral surface thereof, thereby forming the pilot hole into the insertion hole 25. A cutting process is also performed using a cutter, which is a rotary cutting tool, to form the slits 22 and the gaps 35. In this manner, the first yoke 17 of this example is obtained.

[0151] 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 to ensure the strength of the ends of the base portion 20 on both axial sides.

[0152] The base 20 of the first yoke 17 in this example has grooves 26a-26d extending in a direction including an axial component in a portion of the outer circumferential surface that is offset from the slits 22 in the circumferential direction. Therefore, in the first yoke 17 in this example, the rigidity of the portion of the base 20 where the grooves 26a-26d are formed is reduced. In other words, the portion of the base 20 where the grooves 26a-26d are formed becomes a low rigidity portion. Therefore, the deformation resistance of the first yoke 17 when the bolt 24 is tightened is reduced.

[0153] 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.

[0154] Both ends of the recessed grooves 26a to 26d are closed ends that are closed in the axial direction. This ensures that the base 20 has a sufficient thickness at both axial ends. This ensures that the base 20 has sufficient strength at both axial ends.

[0155] In this example, as described above, since the strength of both ends of the base 20 in the axial direction is ensured, the through-holes 33 communicating with the insertion holes 25 can be provided in the recessed grooves 26a to 26d. Therefore, the weight of the first yoke 17 can be reduced compared to a case where the through-holes 33 are not provided. Furthermore, since the through-holes 33 are provided in the recessed grooves 26a to 26d at portions where the axial positions overlap with the pair of flange portions 21a and 21b, it is also possible to visually check through the through-holes 33 whether the pinion shaft 13 is inserted at a proper position in the insertion hole 25. Furthermore, since the through-holes 33 are provided in portions where the axial positions overlap with the mounting holes 23a and 23b, it is also possible to visually check through the through-holes 33 whether the middle portion of the bolt 24 is engaged with the engagement recessed groove 34 of the pinion shaft 13.

[0156] In this embodiment, the grooves 26a to 26d are formed by hot forging, which reduces the processing cost compared to forming the grooves 26a to 26d by cutting or the like.

[0157] In this example, the grooves 26a-26d include only the axial component and have a linear shape that extends linearly in the axial direction, so that it is possible to increase the number of grooves 26a-26d that can be formed on the outer circumferential surface of the base 20, effectively reducing the weight of the first yoke 17. In addition, the shape of the protrusions 42 provided on the inner circumferential surfaces of the split dies 40a, 40b can be simplified, so that the manufacturing cost of the first yoke 17 can be reduced.

[0158] In this example, the multiple recessed grooves 26a to 26d are arranged symmetrically with respect to the imaginary plane β. Therefore, the rigidity of the base 20 is reduced equally on both sides of the imaginary plane β. Therefore, the inner peripheral surface of the base 20 can tighten the outer peripheral surface of the end of the pinion shaft 13 in a well-balanced manner.

[0159] 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.

[0160] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to FIGS.

[0161] In this example, the base portion 20a of the first yoke 17a has two recessed grooves 26e and 26f.

[0162] The recessed grooves 26e and 26f are aligned with the central axis O of the insertion hole 25 in the first direction. 25 and the central axis O of the slit 22 22 The two are arranged on either side of a virtual plane β (see FIG. 8) that includes the above two components.

[0163] The recessed grooves 26e and 26f are disposed symmetrically with respect to the imaginary plane β.

[0164] In this example, the recessed grooves 26e, 26f extend in a direction that includes an axial component and a circumferential component.

[0165] Specifically, the grooves 26e, 26f extend in a spiral shape obliquely with respect to the axial and circumferential directions. When viewed from the first direction, the grooves 26e, 26f extend in a generally linear shape obliquely in a direction approaching the slit 22 in the second direction as they move from the other axial side toward the one axial side. In other words, when viewed from the first direction, the grooves 26e, 26f are aligned with the central axis O of the mounting holes 23a, 23b. 23 and the central axis O of the insertion hole 25 25 It crosses the imaginary line L perpendicular to the axial direction diagonally.

[0166] One end of the recessed grooves 26e, 26f is disposed near the end (closed end 30) on one axial side of the slit 22, and the other end is disposed near the radially opposite portion of the end on the other axial side of the slit 22. For this reason, a low-rigidity portion made of the recessed grooves 26e, 26f is formed in the base 20a so as to connect the portion near the end (closed end 30) on one axial side of the slit 22 and the portion near the radially opposite portion of the end on the other axial side of the slit 22.

[0167] One end of each of the recessed grooves 26e and 26f does not communicate with one axial end of the slit 22. The other end of the recessed groove 26e does not communicate with the other end of the recessed groove 26f.

[0168] In this embodiment, the recessed grooves 26e, 26f also have closed ends on both sides that are closed in the axial direction.

[0169] That is, one end of grooves 26e, 26f does not open to one axial end face of base 20, and the other end of grooves 26e, 26f does not open to the other axial end face of base 20.

[0170] The recessed grooves 26e, 26f have ends on one side and the ends on the other side at different axial positions.

[0171] In this example, one end of the recessed grooves 26e, 26f is located in the axial middle portion of the base 20a, and the other end of the recessed grooves 26e, 26f is located in a portion of the base 20a closer to the other axial direction.

[0172] One end of each of the recessed grooves 26e, 26f is located on the other axial side of the one axial end (closed end 30) of the slit 22.

[0173] The recessed grooves 26 e and 26 f each have a bottomed portion 32 and a through portion 33 that communicates with the insertion hole 25 .

[0174] The through-holes 33 are provided in the recessed grooves 26e, 26f at portions that overlap with the pair of flange portions 21a, 21b in the axial direction. In this example, the through-holes 33 are provided in the recessed grooves 26e, 26f at portions that overlap with the mounting holes 23a, 23b in the axial direction. In other words, the recessed grooves 26e, 26f have bottomed portions 32 at portions that are out of the axial position of the mounting holes 23a, 23b.

[0175] The axial dimension of the through portion 33 is approximately the same as the diameter of the mounting holes 23a, 23b.

[0176] The length of the recessed grooves 26e, 26f is greater than the width in a direction perpendicular to the length direction.

[0177] The width of the recessed grooves 26e, 26f is constant along the length except for both ends. The depth of the recessed grooves 26e, 26f at the bottomed portion 32 is constant along the length except for both ends.

[0178] The recessed grooves 26e and 26f are aligned with the central axis O of the insertion hole 25 at the bottom portion 32. 25 The cross-sectional shape with respect to an imaginary plane perpendicular to the plane is substantially semicircular (partially circular) or substantially elliptical. The recessed grooves 26e and 26f are cast-out grooves.

[0179] The first yoke 17a of this example is manufactured by carrying out hot forging, cutting, and the like, in the same manner as the first yoke 17 of the first example.

[0180] In the present embodiment, the base 20a of the first yoke 17a is formed with a low-rigidity portion consisting of the recessed grooves 26e and 26f, so as to connect a portion adjacent to the end (closed end 30) on one axial side of the slit 22 with a portion adjacent to the radially opposite end of the other axial side of the slit 22. Therefore, when the bolt 24 is tightened, the portion of the first yoke 17a located on the other axial side of the recessed grooves 26e and 26f (a substantially triangular portion as viewed from the first direction) can be efficiently deformed. As a result, the deformation resistance of the first yoke 17a when the bolt 24 is tightened is efficiently reduced, and the tightening force of the base 20a is sufficiently ensured.

[0181] The other configurations and effects of the second example are the same as those of the first example.

[0182] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to FIGS.

[0183] In the first yoke 17b of this embodiment, the pair of flange portions 21c, 21d are separate from the base portion 20b.

[0184] In this example, a pair of flange portions 21c, 21d are provided on a part of a fastening member 45.

[0185] The fastening member 45 has a partially cut cylindrical shape as a whole, and has an end face shape that is substantially U-shaped. The fastening member 45 has a pair of flange portions 21c, 21d and a connecting tube portion .

[0186] The connecting cylinder portion 46 has a semi-cylindrical shape and connects the pair of flange portions 21c, 21d.

[0187] The fastening member 45 has a fitting hole 47 in a portion surrounded by the pair of flange portions 21c, 21d and the connecting tube portion .

[0188] The fastening member 45 is attached to the base portion 20b by inserting the other axial end of the base portion 20b into the fitting hole 47.

[0189] 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.

[0190] The other configurations and effects of the third example are the same as those of the first example.

[0191] [Example 4] A fourth embodiment of the present disclosure will be described with reference to FIGS.

[0192] 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.

[0193] 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.

[0194] The intermediate shaft 6 a includes a first shaft 48 , a second shaft 49 , and a coupling device 50 .

[0195] The first shaft 48 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.

[0196] The second shaft 49 is configured so that its overall length is extendable even in a steady state in which no automobile collision has occurred.

[0197] The first shaft 48 and the second shaft 49 are two rotating shafts that are arranged coaxially and rotate by operating the steering wheel 2 (see FIG. 1).

[0198] The coupling device 50 connects an end of the first shaft 48 and an end of the second shaft 49 in a torque-transmittable manner.

[0199] The coupling device 50 has a base 20 and a pair of flange portions 21a, 21b. Unlike the first yoke 17 of the first example, the coupling device 50 of this example does not have a coupling portion. The coupling device 50 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.

[0200] In this example, one axial end of the second shaft 49 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 (see FIG. 12) provided on the outer peripheral surface of the end of the second shaft 49 are engaged with each other through serrations.

[0201] The other axial end of the first shaft 48 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 48 are fixed by welding with a weld bead portion 51.

[0202] The base 20 of the connecting device 50 of this embodiment has grooves 26a-26d that extend in a direction including an axial component and have both ends closed in the axial direction at a portion that is out of the slit 22 in the circumferential direction. Therefore, according to the connecting device 50 of this embodiment, it is possible to reduce the deformation resistance of the connecting device 50 when the bolt 24 (see FIG. 3) is tightened, and the strength of both ends of the base 20 on the axial side can be ensured. In addition, the grooves 26a-26d have through-holes 33 that communicate with the insertion hole 25 at a portion where the grooves 26a-26d overlap with the pair of flanges 21a and 21b in the axial direction, so that the weight of the connecting device 50 can be reduced. In addition, it is also possible to visually check through the through-holes 33 whether the end of the second shaft 49 is inserted into the connecting device 50 at the appropriate position.

[0203] The other configurations and effects of the fourth example are the same as those of the first example.

[0204] 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]

[0205] 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 Slit 23a, 23b Mounting holes 24 Volts 25 Insertion hole 26a~26f Concave groove 27 Female serrated teeth 28 Male serrated teeth 29 Missing tooth area 30 closed end 31 Open end 32 Bottomed part 33 Penetration 34 Engagement groove 35 Gap 36 Connecting part 37a, 37b Arm section 38 Through hole 39 Materials 40a, 40b split mold 41 Intermediate materials 42 Projection part 43 Small convex part 44 Otokobu 45 Fastening member 46 Connecting cylinder part 47 Fitting hole 48 1st Shaft 49 2nd Shaft 50 Coupling device 51 Weld bead 52 Deep hole bottom part 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 the axial direction, a slit disposed at one location in the circumferential direction and extending in the axial direction, and a recessed groove, located in a portion of the outer circumferential surface deviating from the slit in the circumferential direction, extending in a direction including the axial component and having both end portions that are closed in the axial direction; The groove has a bottom portion and a through portion communicating with the insertion hole, The through-hole is provided in a portion of the groove that overlaps with the pair of flange portions in the axial direction, The pair of flange portions have mounting holes on the same axis and are disposed on both sides of the slit in the circumferential direction. Clamping device.

2. The clamp device according to claim 1 , wherein the groove includes only a component in the axial direction and has a linear shape.

3. The clamping device according to claim 1 , wherein the groove extends in a direction including an axial component and a circumferential component.

4. 4. The clamping device according to claim 3, wherein the groove extends in a spiral shape obliquely with respect to the axial direction and the circumferential direction.

5. A clamping device as described in claim 4, wherein one end of the groove is positioned near the end of the slit on one axial side, and the other end is positioned near the radially opposite portion of the end of the slit on the other axial side.

6. 6. The clamp device according to claim 5, wherein the one end of the recessed groove is located on the other axial side of the one axial end of the slit.

7. The clamp device according to claim 1 , wherein the base portion has a plurality of the recessed grooves.

8. The clamp device according to claim 7 , wherein the plurality of recessed grooves are disposed symmetrically with respect to an imaginary plane including a central axis of the insertion hole and a central axis of the slit.

9. 8. The clamp device according to claim 7, wherein the base portion has a plurality of the recessed grooves on both sides of an imaginary plane including a central axis of the insertion hole and a central axis of the slit.

10. 2. The clamp device according to claim 1, wherein a cross-sectional shape of the bottomed portion of the recessed groove with respect to an imaginary plane perpendicular to a central axis of the insertion hole is substantially semicircular or substantially semielliptical.

11. 2. The clamping device according to claim 1, wherein the recessed groove is a cast groove.

12. The clamp device according to claim 1 , wherein the through portion is provided in a portion of the groove that overlaps with the mounting hole in the axial direction.

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

14. The clamping device of claim 13 , wherein the base portion has female serration teeth on an inner circumferential surface.

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

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

17. The clamping device according to claim 16, wherein the connecting portion is constituted by a pair of arm portions.

18. The clamp device according to claim 17 , wherein one of the pair of arms is disposed at a position where its phase in the circumferential direction coincides with that of the slit.

19. A method for manufacturing a clamping device according to any one of claims 1 to 18, comprising the steps of: The method includes a step of hot forging a material to form an intermediate material having the groove on an outer circumferential surface thereof. A method for manufacturing a clamping device.

20. The method for manufacturing a clamp device according to claim 19, further comprising the step of hot forging the material using a pair of split dies.

21. 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 17 or 18. Steering gear.

22. 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 16. Steering gear.

Images