(19) TZZ¥_ZZ¥¥_T

(11) EP 3 100 933 A1

(12) EUROPEAN PATENT APPLICATION

(43) Date of publication: (51) Int Cl.: 07.12.2016 Bulletin 2016/49 B62D 5/00 (2006.01) G05G 5/03 (2008.04)

(21) Application number: 16172094.1

(22) Date of filing: 31.05.2016

(84) Designated Contracting States: (71) Applicant: KABUSHIKI KAISHA TOKAI RIKA AL AT BE BG CH CY CZ DE DK EE ES FI FR GB DENKI SEISAKUSHO GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO Niwa-gun, PL PT RO RS SE SI SK SM TR Aichi 480-0195 (JP) Designated Extension States: BA ME (72) Inventor: URUSHIBATA, Takanori Designated Validation States: Niwa-gun, Aichi 480-0195 (JP) MA MD (74) Representative: TBK (30) Priority: 05.06.2015 JP 2015114806 Bavariaring 4-6 80336 München (DE)

(54) ROTATIONAL OPERATION DEVICE

(57) A rotational operation device (1) includes a hold- rotation direction of the rotation shaft (21). The case (13) er (32) fixed to a rotation shaft (21), a torsion coil spring includes a first groove (51/53) that receives the first pro- (42), and a case (13) accommodating the holder (32) and trusion. The holder (32) includes a second groove (52/54) the torsion coil spring (42). The torsion coil spring (42) that receives the second protrusion. The first and second includes a coil (43), fitted to the rotation shaft (21), and protrusions (44,45) are spaced apart by an invariable in- two protrusions (44,45), located at opposite ends of the terval (L) set by a fixed length (P) between the first and coil. When the rotation shaft (21) is rotated, the case (13) second grooves. The fixed length (P) is set to a distance restricts movement of the first protrusion (44/45), and the that produces a gap between coil windings when the tor- holder (32) pushes the second protrusion (45/44) in a sion coil spring (42) is in a load-free state. EP 3 100 933 A1

Printed by Jouve, 75001 PARIS (FR) 1 EP 3 100 933 A1 2

Description invention. [0007] It is to be understood that both the foregoing [0001] This disclosure relates to a rotational operation general description and the following detailed description device that uses a torsion coil spring to generate an op- are exemplary and explanatory and are not restrictive of erational reaction force. 5 the invention, as claimed. [0002] Japanese Laid-Open Patent Publication No. [0008] The embodiments, together with objects and 2014-41469 describes a prior art example of a rotational advantages thereof, may best be understood by refer- operation device. The rotational operation device de- ence to the following description of the presently pre- scribedin the publicationincludes a steeringshaft, a hold- ferred embodiments together with the accompanying er, a torsion coil spring, and a case. The steering shaft 10 drawings in which: rotatesintegrally with asteering wheel. The holderis fixed to the steering shaft. The torsion coil spring is fitted onto Fig. 1 is an exploded perspective view illustrating the steering shaft. The case accommodates the holder one embodiment of a steering device; andthe torsion coilspring. The torsioncoil spring includes Fig. 2A is a cross-sectional view illustrating the lo- two protrusions that are located at opposite ends of the 15 cation of a holder piece when the steering shaft is coil. The case supports one of the two protrusions in an located at a reference position; immovable manner. The holder supports the other one Fig. 2B is a cross-sectional view illustrating the lo- of the two protrusions. Rotation of the steering shaft ap- cation of the holder piece when the steering shaft is plies force to the protrusion supported by the holder and rotated from the reference position in the counter- twists the torsion coil spring. In this structure, when the 20 clockwise direction; steering shaft rotates and twists the torsion coil spring, Fig. 2C is a cross-sectional view illustrating the lo- the twisting force is transmitted as an operational reaction cation of a semi-cylindrical step when the steering force to the steering wheel. This allows the user to per- shaft is located at the reference position; ceive the operational reaction force. Fig. 3 is a perspective view of a torsion spring; [0003] It is desirable that the operational reaction force 25 Fig. 4A is a perspective view illustrating grooves of be changed in the proximity of the rotational terminal end a cylindrical case and a holder; of the steering wheel. Fig. 4B is a front view of the torsion spring in a load- [0004] It is an object of the present invention to provide free state (initial state); a rotational operation device capable of changing the op- Fig. 4C is a front view of the torsion spring in a twisted erational reaction force. 30 state; and [0005] One embodiment is a rotational operation de- Fig. 5 is a graph illustrating the relationship of the vice including a rotation shaft, a holder, a torsion coil rotation angle and the operational reaction force. spring, and a case. The rotation shaft is rotated when an operation member is rotated. The holder is fixed to the [0009] One embodiment of a rotational operation de- rotation shaft. The torsion coil spring includes a coil and 35 vice will now be described. two protrusions. The rotation shaft is inserted through [0010] Fig. 1 illustrates a steering device 1 that is one the coil, and the two protrusions are located at opposite example of a rotational operation device. The steering ends of the coil. The case accommodates the holder and device 1 includes a plate 11 fixed to a vehicle body (not the torsion coil spring. The holder and the case are con- illustrated). The plate 11 includes a plate hole 12. A cy- figured to twist the coil when the rotation shaft is rotated 40 lindrical case 13 is fixed to the front surface of the plate by restricting movement of one of the protrusions with 11. The cylindrical case 13 extends in the front-rear di- the case and pushing the other one of the protrusions in rection of the steering device 1. The cylindrical case 13 a rotation direction of the rotation shaft with the holder. is coaxial with the plate hole 12. Although not illustrated The case includes a first groove that receives the one of in detail, the front end of the cylindrical case 13 includes the protrusions. The holder includes a second groove 45 a flange 14 having a diameter that gradually increases that receives the other one of the protrusions. The two toward the front. A spring stopper 15 projects from the protrusions are spaced apart in an axial direction of the inner surface of the cylindrical case 13. The spring stop- rotation shaft by an interval that is invariable and set by per 15 extends in the axial direction of the cylindrical case a fixed length between the first groove of the case and 13. Further, the inner surface of the cylindrical case 13 the second groove of the holder. The fixed length is set 50 includes a first rotation restriction projection 18 and a to a distance that produces a gap between windings of second rotation restriction projection 19. As illustrated in the coil when the torsion coil spring is in a load-free state, Fig. 2C, when viewing the cylindrical case 13 from the with the two protrusions supported by the first and second front in the axial direction, the spring stopper 15 is located grooves. at the twelve o’clock position, the first rotation restriction [0006] Other aspects and advantages of the embodi- 55 projection 18 is located at the ten o’clock position, and ments will become apparent from the following descrip- the second rotation restriction projection 19 is located at tion, taken in conjunction with the accompanying draw- the two o’clock position. In the present example, the first ings, illustrating by way of example the principles of the rotation restriction projection 18 is located at a position

2 3 EP 3 100 933 A1 4 separated by 100° in the clockwise direction from the six rotates and the semi-cylindrical step 32b contacts the o’clock position, and the second rotation restriction pro- restriction projection 37. When the steering shaft 21 is jection 19 is located at a position separated by 100° in further rotated, the semi-cylindrical step 32b of the holder the counterclockwise direction from the six o’clock posi- 32 pushes the restriction projection 37 and rotates the tion. 5 rotation stopper 33. Thus, the steering shaft 21 can be [0011] A cover 16 is fixed to the flange 14. The cover rotated to a position where the restriction projection 37, 16 includes a cover hole 17 that is coaxial with the cylin- which is pushed by the holder 32, contacts the first rota- dricalcase 13. A post-shapedsteering shaft21 is inserted tion restriction projection 18 or the second rotation re- through the plate hole 12 of the plate 11, the cylindrical striction projection 19. The gear 31, the holder 32, and case 13, and the cover hole 17 of the cover 16. The steer- 10 the rotation stopper 33 are in contact with one another ing shaft 21 is rotationally supported by a plate bearing in this order in the axial direction. The retaining ring 34 22, which is received in the plate hole 12, and a cover restricts axial displacement of the gear 31, the holder 32, bearing 27, which is received in the cover hole 17. A and the rotation stopper 33 relative to the steering shaft steering wheel 20, which is operable by a user, is coupled 21. to the front end of the steering shaft 21. The steering15 [0014] A cylindrical spacer 41 is fitted onto the steering wheel 20 corresponds to an operation member, and the shaft 21 between the retaining ring 34 and the plate bear- steering shaft 21 corresponds to a rotation shaft. ing 22. A torsion spring 42 is fitted onto the spacer 41. [0012] A gear 31, a holder 32, a rotation stopper 33, The torsion spring 42 is formed from a coil of a metal wire and a retaining ring 34 are fitted onto the steering shaft wound into a spiral form. The torsion spring 42 corre- 21 between the cover bearing 27 and the plate bearing 20 sponds to a torsion coil spring. The spacer 41 is located 22. A rotary damper 35, which is rotationally supported between the steering shaft 21 and the torsion spring 42 by the flange 14 of the cylindrical case 13, is engaged and prevents contact of the steering shaft 21 with the with the gear 31. The rotary damper 35 reduces the ro- torsion spring 42. tation speed of the gear 31 and the steering shaft 21. [0015] As illustrated in Fig. 3, the torsion spring 42 in- The holder 32 includes a cylindrical holder body 32a and 25 cludes a coil 43 and first and second protrusions 44 and a semi-cylindrical step 32b, which is continuous with the 45, which are located at the two opposite ends of the coil rear surface of the holder body 32a. The holder body 32a 43. When the torsion spring 42 is coupled to the spacer is fitted onto the steering shaft 21. Accordingly, the holder 41, the first protrusion 44 is located at the side closer to 32 rotates integrally with the steering shaft 21. A holder the plate 11, and the second protrusion 45 is located at piece 36 extends from the rear side of the semi-cylindrical 30 the side closer to the steering wheel 20. The first and step 32 in the axial direction of the cylindrical case 13. second protrusions 44 and 45 are upwardly bent parallel As illustrated in Fig. 2A, the holder piece 36 is located to each other. Referring to Fig. 2A, as viewed from the between the spring stopper 15 and the steering shaft 21 front of the steering shaft 21, the first protrusion 44 is in the vertical direction of the steering device 1 (radial located at the clockwise side of the holder piece 36 and direction of steering shaft 21). The holder piece 36 has 35 the spring stopper 15. Further, the first protrusion 44 con- a dimension in the lateral direction (direction of tangent tacts the right surfaces of the holder piece 36 and the on outer circumferential surface of steering shaft 21) that spring stopper 15. The second protrusion 45 is located is set to be the same as the dimension of the spring stop- at the counterclockwise side of the holder piece 36 and per 15 in the lateral direction. The steering shaft 21 in- the spring stopper 15. Further, the second protrusion 45 cludes a reference position set in alignment with the lat- 40 is in contact with the left surfaces of the holder piece 36 erally central part of the holder piece 36 and the laterally and the spring stopper 15. central part of the spring stopper 15. [0016] The right surface of the spring stopper 15 in- [0013] Referring to Figs. 1 and 2C, the rotation stopper cludes a first groove 51, and the left surface of the holder 33 is generally cylindrical and rotatable relative to the piece 36 includes a second groove 52. The left surface steering shaft 21. As illustrated in Fig. 2C, a restriction 45 of the spring stopper 15 includes a third groove 53, and projection 37 projects in the radial direction from the outer the right surface of the holder piece 36 includes a fourth circumferential surface of the rotation stopper 33. The groove 54. In the present example, the first groove 51 in rotation stopper 33 is arranged so that the first and sec- the right surface of the spring stopper 15 and the fourth ond rotation restriction projections 18 and 19 are located groove 54 in the right surface of the holder piece 36 define in the rotation path of the restriction projection 37. Fur- 50 a first cooperative groove that supports the first protru- ther, the restriction projection 37 is located in the rotation sion 44. Further, the third groove 53 in the left surface of path of the semi-cylindrical step 32b. Referring to Fig. the spring stopper 15 and the second groove 52 in the 2C, as viewed from the front of the steering shaft 21, the left surface of the holder piece 36 define a second coop- restriction projection 37 is located at a position separated erative groove that supports the second protrusion 45. from the first rotation restriction projection 18 in the coun- 55 [0017] Referring to Fig. 4A, the distance between the terclockwise direction and separated from the second first cooperative groove (51 and 54) and the second co- rotation restriction projection 19 in the clockwise direc- operative groove (53 and 52) in the axial direction defines tion. When the steering shaft 21 is rotated, the holder 32 a fixed length P that sets the pitch of the windings of the

3 5 EP 3 100 933 A1 6 coil 43 in a load-free state (initial state). Referring to Fig. separated from the fourth groove 54, and the second 4B, the fixed length P is set to a distance that produces protrusion 45 is separated from the third groove 53. How- gaps between the windings of the coil 43 when the torsion ever, the first protrusion 44 remains in the first groove spring 42 is in the load-free state, with the first and second 51, and the second protrusion 45 remains in the second protrusions 44 and 45 supported by the first and second 5 groove 52. Thus, the interval L between the first protru- cooperative grooves. When the first and second protru- sion 44 and the second protrusion 45 is the same as the sions 44 and 45 are supported by the first and second fixed length P. Accordingly, referring to Fig. 4C, the in- cooperative grooves, the interval L between the first and terval L between the first protrusion 44 and the second second protrusions 44 and 45 of the torsion spring 42 in protrusion 45 is invariable even when the coil 43 is twist- the axial direction is set to the fixed length P between the 10 ed. As the twisting of the coil 43 increases the number first and second cooperative grooves. In other words, the of windings, the gaps between the windings gradually interval L between the first and second protrusions 44 become smaller while the interval L remains the same. and 45 is invariable and equal to the fixed length P be- [0022] When gaps are eliminated from between adja- tween the first and second cooperative grooves. This re- cent windings, frictional force is generated at the portions stricts axial movement of the first and second protrusions 15 where the windings contact one another. In addition to 44 and 45 of the torsion spring 42. the spring force derived from the elastic force stored in [0018] The operation of the steering device 1 will now the coil 43, the frictional force is transmitted as opera- be described. Here, a case will be described in which the tional reaction force to the steering wheel 20. Thus, sub- steering wheel 20 is operated in the forward direction sequent to the generation of the frictional force, the op- (counterclockwise direction) to rotate the steering shaft 20 erational reaction force increases at a higher rate as the 21 from the reference position. rotational angle (absolute value) of the steering shaft 21 [0019] Referring to Fig. 2B, when the steering shaft 21 increases (refer to Fig. 5). is rotated in the counterclockwise direction, the holder [0023] The same applies to when the steering shaft 21 32 is rotated integrally with the steering shaft 21 in the is rotated in the reverse direction (clockwise direction). counterclockwise direction. The holder piece 36 is also 25 In this case, the spring stopper 15 restricts movement of rotated in the counterclockwise direction. Here, the left the second protrusion 45, which remains in the third surfaceof theholder piece 36 is in contact withthe second groove 53. Further, the holder piece 36 pushes the first protrusion 45. Accordingly, the holder piece 36 pushes protrusion 44, which remains in the fourth groove 54. and moves the second protrusion 45 in the counterclock- Gaps become smaller between the windings of the coil wise direction. The torsion spring 42 stores elastic force 30 43. When the gaps are eliminated and frictional force is as the holder piece 36 rotates in the counterclockwise generated, the frictional force is added to the operational direction. That is, the coil 43 is twisted when the second reaction force. Thus, referring to Fig. 5, subsequent to protrusion 45 of the torsion spring 42 moves in the coun- the generation of the frictional force, the operational re- terclockwise direction. When the coil 43 is twisted, the action force increases at a higher rate as the rotational twisting force is transmitted to the steering wheel 20 as 35 angle (absolute value) of the steering shaft 21 increases. an operational reactive force. This allows the user to per- [0024] The present embodiment has the advantages ceive the operation reaction force. described below. [0020] The process in which the operational reactive force is generated will now be described in detail. As (1) When the steering shaft 21 is rotated, the holder illustrated in Fig. 2A, when the steering wheel 20 is not 40 32 and the case 13 twist the coil 43 as the case 13 operated, the first protrusion 44 is received in the first restricts movement of one of the two protrusions 44 cooperative groove, which is defined by the first groove and 45 and the holder 32 pushes the other one of 51 and the fourth groove 54, and the second protrusion the two protrusions 44 and 45 in the rotation direc- 45 is received in the second cooperative groove, which tion. The two protrusions 44 and 45 are supported is defined by the third groove 53 and the second groove 45 by both of the holder 32 and the case 13 not only 52. Here, referring to Fig. 4B, the torsion spring 42 is in when the steering shaft 21 is in a non-rotated state a load-free state (initial state), and gaps extend between but also when the steering shaft 21 is rotated. For the windings of the coil 43. The interval L between the example, when the steering shaft 21 is rotated in the first protrusion 44 and the second protrusion 45 is invar- forward direction (counterclockwise direction), the iable and set by the fixed length P between the first co- 50 holder 32 (holder piece 36 in present example) holds operative groove and the second cooperative groove. the second protrusion 45 in the second groove 52 [0021] From this state, referring to Fig. 2B, when the and pushes the second protrusion 45 in the counter- steering wheel 20 is operated and the steering shaft 21 clockwise direction, while the case 13 (spring stop- is rotated in the counterclockwise direction, the spring per 15 in present example) holds the first protrusion stopper 15 restricts movement of the first protrusion 44, 55 44 in the first groove 51 and restricts movement of which remains in the first groove 51. Further, the holder the first protrusion 44. The interval L between the piece36 pushes the second protrusion 45,which remains protrusions 44 and 45 is invariable and set by the in the second groove 52. Here, the first protrusion 44 is fixed length P between the first groove 51 of the case

4 7 EP 3 100 933 A1 8

13 and the second groove 52 of the holder 32. The of Fig. 5. fixed length P is set to a distance that produces gaps [0027] In addition to the gap between the windings of between the windings of the coil 43 when the torsion the coil 43, the fixed length P illustrated in Fig. 4A may spring 42 is in a load-free state, with the first and be changed. This will also change the changing point of second protrusions 44 and 45 supported by the first 5 the operational reaction force (position where gradient and second grooves 51 and 52. In this structure, changes in graph of Fig. 5). when the steering shaft 21 is rotated and the coil 43 [0028] One or more further cooperative grooves may is twisted, the interval L between the two protrusions be set in addition to the first and second cooperative 44 and 45 is invariable and the same as the fixed grooves. In such a case, selection of the fixed length P length P. Thus, the gaps between the windings grad- 10 or the gap between windings in the initial state (i.e., load- ually become smaller as the windings increases. free state) allows for adjustment of the changing point of When the gaps are eliminated and the windings the operational reaction force. come into contact with one another, frictional force [0029] When the rotation direction of the steering shaft is generated at the portions where the windings con- 21 is limited to one direction, for example, the third groove tact one another. As a result, in addition to spring 15 53 and the fourth groove 54 may be omitted. In this case, force, the frictional force is transmitted as operational the spring stopper 15 restricts movement of the first pro- reaction force to the steering wheel 20. This changes trusion 44, which remains in the first groove 51, and the (increases) theoperational reaction force inthe prox- holder piece 36 pushes the second protrusion 45, which imity of the rotational terminal end of the steering remains in the second groove 52. In the same manner, wheel 20. 20 the first groove 51 and the second groove 52 may be (2) When the steering shaft 21 is rotated in the for- omitted, and the third groove 53 and the fourth groove ward direction (counterclockwise direction), the 54 may be used when restricting the rotation direction of spring stopper 15 restricts movement of the first pro- the steering shaft 21 to one direction. trusion 44, which remains in the first groove 51. Fur- [0030] The gaps between the windings do not have to ther, the holder piece 36 pushes the second protru- 25 be constant. The gaps between the windings may be sion 45, which remains in the second groove 52. intentionally changed for design reasons or differ within When the steering shaft 21 is rotated in the reverse the range of manufacturing tolerances. direction (clockwise direction), the spring stopper 15 [0031] The application of the rotational operation de- restricts movement of the second protrusion 45, vice is not limited to the steering device 1. For example, which remains in the third groove 53. Further, the 30 the rotational operation device may be applied to a rotary holder piece 36 pushes the first protrusion 44, which switch. The rotary switch includes, for example, a rota- remains in the fourth groove 54. Thus, regardless of tional dial (structure corresponding to steering wheel 20) whether the steering shaft 21 is rotated in the forward for adjusting the lighting, temperature, or volume. When direction or the reverse direction, the interval L be- the dial is rotated, the torsion spring 42 is twisted in ac- tween the two protrusions 44 and 45 is invariable 35 cordance with the rotation of a dial rotation shaft (struc- and the same as the fixed length P. This allows for ture corresponding to steering shaft 21), and an opera- application to both of when the steering wheel 20 is tional reaction force (spring force and frictional force) is operated to rotate the steering shaft 21 in the forward transmitted to the dial. direction and when the steering wheel 20 is operated [0032] The present examples and embodiments are to to rotate the steering shaft in the reverse direction. 40 be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, [0025] It should be apparent to those skilled in the art but may be modified within the scope and equivalence that the foregoing embodiments may be employed in of the appended claims. many other specific forms without departing from the A rotational operation device (1) includes a holder (32) scope of this disclosure. Particularly, it should be under- 45 fixed to a rotation shaft (21), a torsion coil spring (42), stood that the foregoing embodiments may be employed and a case (13) accommodating the holder (32) and the in the following forms. torsion coil spring (42). The torsion coil spring (42) in- [0026] Referring to Fig. 4B, the gaps between the wind- cludes a coil (43), fitted to the rotation shaft (21), and two ings of the coil 43, that is, the pitch of the windings may protrusions (44,45), located at opposite ends of the coil. be changed when the torsion spring 42 is in a load-free 50 When the rotation shaft (21) is rotated, the case (13) re- state. For example, when the gaps between the windings stricts movement of the first protrusion (44/45), and the in a load-free state are set to be larger, the steering shaft holder (32) pushes the second protrusion (45/44) in a 21 needs to be rotated by a larger rotation angle until the rotation direction of the rotation shaft (21). The case (13) windings contact one another and generate frictional includes a first groove (51/53) that receives the first pro- force. This increases the rotational angle at which the 55 trusion. The holder (32) includes a second groove (52/54) gradient changes in the graph of Fig. 5. On the contrary, that receives the second protrusion. The first and second a smaller gap between the windings decreases the rota- protrusions (44,45) are spaced apart by an invariable in- tional angle at which the gradient changes in the graph terval (L) set by a fixed length (P) between the first and

5 9 EP 3 100 933 A1 10 second grooves. The fixed length (P) is set to a distance configured to receive the second protrusion that produces a gap between coil windings when the tor- (45), and a fourth groove (54) configured to re- sion coil spring (42) is in a load-free state. ceive the first protrusion (44); the holder (32) and the case (13) are configured 5 so that when the rotation shaft (21) is rotated in Claims a forward direction, the holder (32) holds the second protrusion (45) with the second groove 1. A rotational operation device (1) comprising: (52) and pushes the second protrusion (45) in the forward direction, while the case (13) holds a rotation shaft (21) rotated when an operation 10 the first protrusion (44) with the first groove (51) member (20) is rotated; and restricts movement of the first protrusion a holder (32) fixed to the rotation shaft (21); (44); and a torsion coil spring (42) including a coil (43) and the holder (32) and the case (13) are configured two protrusions (44,45) located at opposite ends so that when the rotation shaft (21) is rotated in of the coil (43), wherein the rotation shaft (21) 15 a reverse direction, the holder (32) holds the first is inserted through the coil (43); and protrusion (44) with the fourth groove (54) and a case (13) that accommodates the holder (32) pushes the first protrusion (44) in the reverse and the torsion coil spring (42), wherein direction, while the case (13) holds the second the holder (32) and the case (13) are configured protrusion (45) with the third groove (53) and to twist the coil (43) when the rotation shaft (21) 20 restricts movement of the second protrusion is rotated by restricting movement of one of the (45). protrusions (44,45) with the case (13) and push- ing the other one of the protrusions (44,45) in a 3. The rotational operation device (1) according to rotation direction of the rotation shaft (21) with claim 2, wherein: the holder (32), 25 the rotational operation device (1)character- the holder (32) and the case (13) are configured ized in that: so that when the rotation shaft (21) is rotated in the forward direction, the first protrusion (44) is the case (13) includes a first groove (51/53) separated from the fourth groove (54) of the configured to receive the one of the protru- 30 holder (32), and the second protrusion (45) is sions (44,45); separated from the third groove (53) of the case the holder (32) includes a second groove (13); and (52/54) configured to receive the other one the holder (32) and the case (13) are configured of the protrusions (44,45); so that when the rotation shaft (21) is rotated in the two protrusions (44,45) are spaced35 the reverse direction, the second protrusion (45) apart in an axial direction of the rotation is separated from the second groove (52) of the shaft (21) by an interval (L) that is invariable holder (32), and the first protrusion (44) is sep- and set by a fixed length (P) between the arated from the first groove (51) of the case (13). first groove (51/53) of the case (13) and the second groove (52/54) of the holder (32); 40 4. The rotational operation device (1) according to and claim 2 or 3, wherein the fixed length (P) is set to a distance that the first groove (51) of the case (13) and the fourth produces a gap between windings of the coil groove (54) of the holder (32) define a first cooper- (43) when the torsion coil spring (42) is in a ative groove that supports the first protrusion (44) load-free state, with the two protrusions45 when the torsion coil spring (42) is in the load-free (44,45) supported by the first and second state, and grooves. the third groove (53) of the case (13) and the second groove (52) of the holder (32) define a second co- 2. The rotational operation device (1) according to operative group that supports the second protrusion claim 1, wherein: 50 (45) when the torsion coil spring (42) is in the load- free state. the two protrusions (44,45) comprise a first pro- trusion (44) and a second protrusion (45); the case (13) includes the first groove (51) con- figured to receive the first protrusion (44), and a 55 third groove (53) configured to receive the sec- ond protrusion (45); the holder (32) includes the second groove (52)

6 EP 3 100 933 A1

7 EP 3 100 933 A1

8 EP 3 100 933 A1

9 EP 3 100 933 A1

10 EP 3 100 933 A1

5

10

15

20

25

30

35

40

45

50

55

11 EP 3 100 933 A1

5

10

15

20

25

30

35

40

45

50

55

12 EP 3 100 933 A1

REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description

• JP 2014041469 A [0002]

13