CN113412380B

CN113412380B - Tensioning regulator

Info

Publication number: CN113412380B
Application number: CN201980091364.6A
Authority: CN
Inventors: 中道胜弘; 杉田治臣; 古户匠
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2019-03-28
Filing date: 2019-03-28
Publication date: 2024-05-17
Anticipated expiration: 2039-03-28
Also published as: CN113412380A; WO2020194679A1; JP7128956B2; JPWO2020194679A1

Abstract

The invention provides a tensioning adjuster. The tension adjuster (25) has: a friction member (55) that is urged against the drive shaft (38) in the axial direction and applies resistance to rotation of the drive shaft (38) about the axis (27) in response to friction torque with the drive shaft (38), and an elastic member (58) that applies urging force to the friction member (55) in the axial direction against the urging member (26 a). A large diameter shaft (41) which is coaxial with the axis (27) and is received by the thrust member (26 a) and which is expanded outward from a virtual cylindrical surface (62) which is coaxial with the axis and is received by the point of application of the elastic member (58) to the friction member (55) is formed at the shaft end of the drive shaft (38). This can generate a stable friction torque with respect to the drive shaft.

Description

Tensioning regulator

Technical Field

The present invention relates to a tensioning adjuster having: a drive shaft rotatably supported about an axis and having an external thread engraved in the shaft body; a thrust member that restricts displacement of the drive shaft in a radial direction and supports an axial end of the drive shaft in a thrust direction; a thrust body which is restricted from relative rotation about an axis relative to the thrust member and has an internal thread on an inner surface thereof which engages with the external thread; and a spring for generating an elastic force for driving the drive shaft around the axis, and applying a propelling force to the propelling body in a direction away from the thrust member in response to engagement of the male screw and the female screw.

Background

Patent document 1 discloses a tensioning adjuster having a thrust body having an internal thread engaged with an external thread of a drive shaft, which is advanced in correspondence with engagement of the external thread and the internal thread of a rotating drive shaft. In the tensioning device, the drive shaft is received at the shaft end by a thrust element. The shaft end of the drive shaft is formed with a stepped surface for receiving the annular plate friction member that presses against the thrust member. The friction member applies resistance to rotation of the drive shaft about the axis corresponding to friction torque with the drive shaft. The rotation of the drive shaft is moderately restricted. Thus, the propulsive force of the propulsive body is stabilized.

Prior art literature

Patent literature

Patent document 1: japanese patent No. 4934816

Disclosure of Invention

Technical problem to be solved by the invention

During the generation of friction torque, the coil spring urges the friction member toward the stepped surface. At this time, the coil spring is pushed to the friction member to be radially more outward than the step surface. Because the diameter of the shaft end of the drive shaft is small compared to the diameter of the coil spring, the drive shaft may be unstably supported on the thrust member. The generation of friction torque cannot be well achieved. On the other hand, when a large spring load is applied to the coil spring in order to stabilize the friction torque, the urging force applied to the cam chain may be excessively high.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a tensioning adjuster capable of generating stable friction torque with respect to a drive shaft and avoiding excessive load applied to a cam chain.

Technical scheme for solving technical problems

According to a first aspect of the present invention, a tensioning adjuster has: a drive shaft rotatably supported about an axis and having an external thread engraved in the shaft body; a thrust member that radially restricts displacement of the drive shaft and supports an axial end of the drive shaft in a thrust direction; a thrust body which is restricted from relative rotation about the axis with respect to the thrust member, and which has an internal thread on an inner surface thereof which engages with the external thread; a spring that generates an elastic force for driving the drive shaft around the axis, and applies a thrust force to the thrust body in a direction away from the thrust member in response to engagement of the male screw and the female screw; a friction member that is urged in an axial direction against the drive shaft, and generates friction force with the drive shaft around the axis; and an elastic member that urges the friction member toward the thrust member in the axial direction. In this tensioning adjuster, a large diameter shaft is formed at the shaft end of the drive shaft, and the large diameter shaft is extended further outward than a virtual cylindrical surface coaxial with the axis and inscribed in an action point of the elastic member with respect to the friction member, and is received by the thrust member.

According to a second aspect of the present invention, a tensioning adjuster has: a drive shaft rotatably supported about an axis and having an external thread engraved in the shaft body; a thrust member that radially restricts displacement of the drive shaft and supports an axial end of the drive shaft in a thrust direction; a thrust body which is restricted from relative rotation about the axis with respect to the thrust member, and which has an internal thread on an inner surface thereof which engages with the external thread; a spring that generates an elastic force for driving the drive shaft around the axis, and applies a thrust force to the thrust body in a direction away from the thrust member in response to engagement of the male screw and the female screw; a friction member that is urged in an axial direction against the drive shaft, generating a friction force around the axis between the friction member and the drive shaft; and an elastic member that urges the friction member toward the thrust member in the axial direction. In the tensioning regulator, the drive shaft has: a large diameter shaft accommodated in a recess formed in the thrust member; and a middle diameter shaft formed of a cylinder having a smaller diameter than the large diameter shaft and coaxial with the axis, the middle diameter shaft being coupled to the large diameter shaft in the axis direction, and a first step surface being formed between the middle diameter shaft and the large diameter shaft.

According to the third side surface, the external thread is formed in a small diameter smaller than the large diameter shaft except for the structure of the second side surface.

According to the fourth aspect, in addition to any one of the first to third aspects, the elastic member is provided so as to be rotatable relative to the friction member.

According to the fifth side, in addition to any one of the first to fourth sides, the tensioning regulator has a collar member that surrounds the urging body and has one end located closer to the friction member side than the urging body in the axial direction, and the elastic member is sandwiched between the one end of the collar member and the friction member closer to the friction member side than the urging body in the axial direction.

According to the sixth side, in addition to the structure of the fifth side, a boss that restricts displacement of the elastic member in the radial direction is formed in the friction member or the collar member.

According to a seventh aspect of the present invention, a tensioning adjuster has: a drive shaft rotatably supported about an axis and having an external thread engraved in the shaft body; a thrust member radially restricting displacement of the drive shaft and supporting an axial end of the drive shaft in a thrust direction; a thrust body which is restricted from relative rotation about the axis with respect to the thrust member, and which has an internal thread on an inner surface thereof which engages with the external thread; a spring that generates an elastic force for driving the drive shaft around the axis, and applies a thrust force to the thrust body in a direction away from the thrust member in response to engagement of the male screw and the female screw; a friction member that is urged in an axial direction against the drive shaft, generating a friction force around the axis between the friction member and the drive shaft; and an elastic member that urges the friction member toward the thrust member in the axial direction. In the tensioning regulator, a collar member is provided, which surrounds the urging body and has one end located closer to the friction member than the urging body in the axial direction, and the elastic member is sandwiched between the one end of the collar member and the friction member than the urging body in the axial direction.

According to an eighth aspect of the present invention, a tensioning adjuster has: a drive shaft rotatably supported about an axis and having an external thread engraved in the shaft body; a thrust member that radially restricts displacement of the drive shaft and supports an axial end of the drive shaft in a thrust direction; a thrust body which is restricted from relative rotation about the axis with respect to the thrust member, and which has an internal thread on an inner surface thereof which engages with the external thread; and a spring for generating an elastic force for driving the drive shaft around the axis, wherein the spring applies a pushing force to the pushing body in a direction away from the pushing member in response to engagement of the male screw and the female screw. In this tensioning regulator, there is an elastic member that is urged in the axial direction against the drive shaft, which applies an urging force to the drive shaft against the urging member.

According to a ninth aspect, in addition to the structure of the eighth aspect, the tensioning regulator has a collar member that surrounds the thrust body and is restricted from being displaced in a direction away from the thrust member, and the elastic member is disposed between the collar member and the drive shaft.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the first side, a driving force is applied to the drive shaft around the axis by the action of the spring. When the drive shaft rotates, a propulsive force is applied to the propulsion body in response to engagement of the external thread and the internal thread. At this time, the friction member applies resistance to the rotation of the drive shaft about the axis corresponding to the friction torque with the drive shaft. The rotation of the drive shaft is moderately restricted. Thus, the propulsive force of the propulsive body is stabilized. Since the drive shaft is received by the thrust member by the large diameter shaft which is expanded outward from the point of action of the elastic member, the drive shaft can be stably supported by the thrust member. Friction torque can be generated well between the thrust member and the large-diameter shaft.

According to the second side, a driving force is applied to the drive shaft around the axis by the action of the spring. When the drive shaft rotates, a propulsive force is applied to the propulsion body in response to engagement of the external thread and the internal thread. At this time, the friction member applies resistance to the rotation of the drive shaft about the axis corresponding to the friction torque with the drive shaft. The rotation of the drive shaft is moderately restricted. Thus, the propulsive force of the propulsive body is stabilized. Since the drive shaft is received by the thrust member by the large diameter shaft that extends outward from the intermediate diameter shaft, the drive shaft can be stably supported by the thrust member. Friction torque can be generated well between the thrust member and the large-diameter shaft.

According to the third side surface, the male screw is formed in a small diameter smaller than the large diameter shaft, so that the drive shaft can be stably supported by the thrust member.

According to the fourth aspect, since relative rotation is allowed between the elastic member and the friction member, the elastic member can be prevented from being twisted. The elastic member can accurately apply elastic force to the friction member.

According to the fifth side, the collar member can realize shortening of the elastic member in the axial direction. Therefore, the operation of the elastic member can be stabilized. Because the collar member is partially replaced with the elastic member, the use of a relatively expensive elastic member can be reduced, enabling a reduction in manufacturing costs.

According to the sixth side, since the position of the elastic member is set in the radial direction with respect to the friction member, the elastic member can act on the friction member with a balance force in the circumferential direction. Friction torque can be generated well between the thrust member and the large-diameter shaft.

According to the seventh side, the collar member can realize shortening of the elastic member in the axial direction. Therefore, the operation of the elastic member can be stabilized. Because the collar member is partially replaced with the elastic member, the use of a relatively expensive elastic member can be reduced, enabling a reduction in manufacturing costs.

According to the eighth side, since the elastic member is directly pushed against the drive shaft, the number of parts can be reduced as compared with the case where there are other members between the elastic member and the drive shaft. As the number of parts decreases, the coupling portions of the parts to each other decrease, so that the risk of failure can be reduced.

According to the ninth side, the collar member can realize shortening of the elastic member in the axial direction. Therefore, the operation of the elastic member can be stabilized. Because the collar member is partially replaced with the elastic member, the use of a relatively expensive elastic member can be reduced, enabling a reduction in manufacturing costs.

Drawings

Fig. 1 is a longitudinal sectional side view (first embodiment) of an internal combustion engine according to an embodiment of the present invention.

Fig. 2 is a cross-sectional enlarged view of the tensioning device of the first embodiment (first embodiment) as seen from a cut surface including the axial center.

Fig. 3 is a vector diagram (first embodiment) of arrow 3 of fig. 2.

Fig. 4 is a vector diagram (first embodiment) of arrow 4 of fig. 2.

Fig. 5 is a partially enlarged view corresponding to fig. 2, and is a conceptual view (first embodiment) schematically showing a stopper inserted into a drive shaft.

Fig. 6 is a cross-sectional enlarged view of the tensioning device of the second embodiment (second embodiment) as seen from a cut surface including the axial center.

Fig. 7 is a cross-sectional enlarged view of the tensioning device of the third embodiment (third embodiment) as seen from a cut surface including the axial center.

Fig. 8 is a cross-sectional enlarged view of the tensioning device of the fourth embodiment (fourth embodiment) as seen from a cut surface including the axial center.

Fig. 9 is a cross-sectional enlarged view of the tensioning device of the fifth embodiment (fifth embodiment) as seen from a cut surface including the axial center.

Description of the reference numerals

25 Tensioning regulator; 25a tensioning regulator; 25b tensioning regulator; 25c tensioning regulator; 26a thrust member; a 27 axis; 28 propulsion body; 36 shaft bodies; 37 external threads; 38 drive shafts; 41 large diameter shaft; 43 medium diameter axis; 46 springs (clockwork springs); 48 internal threads; 55 friction members; a 56 collar member; 56 a; 58 elastic members (coil springs); 59 bosses; 62 virtual cylinder surfaces; 71 friction members; a 72 collar member; 72 a; 75 elastic members (O-rings); 76 bosses; 78 virtual cylinder surface; 82 an elastic member (coil spring); 91 a collar member; 94 an elastic member (coil spring); a friction member 101; 103 an elastic member (coil spring); 105 virtual cylinder surface.

Embodiments of the present invention will be described below with reference to the drawings.

First embodiment

Fig. 1 shows an internal combustion engine according to an embodiment of the present invention. The internal combustion engine 11 has: the engine includes a crankcase 13 rotatably supporting a crankshaft 12 about a rotation axis Rx, a cylinder block 14 coupled to the crankcase 13 and guiding a linear reciprocating motion of a piston coupled to the crankshaft 12 by a connecting rod, a cylinder head 15 coupled to the cylinder block 14 and partitioning a combustion chamber between the piston, and a head cover 16 coupled to the cylinder head 15 and accommodating a valve train controlling opening/closing of an intake valve and an exhaust valve facing the combustion chamber. When the intake valve opens as the piston descends, the mixture is introduced into the combustion chamber. When the intake valve is closed and the piston is raised, the mixture is compressed in the combustion chamber. When the mixed gas ignites in the combustion chamber, the mixed gas burns, and the volume of the combustion chamber expands. Exhaust gases are expelled from the combustion chamber as the piston descends, and then as the piston ascends, the exhaust valve opens. In this way, power is taken from the crankshaft 12.

The internal combustion engine 11 is equipped with a valve train 17 that performs opening/closing operations of an intake valve and an exhaust valve at predetermined timing in combination with linear reciprocation of a piston. The valve train 17 includes: the drive sprocket 18 fixed to the crankshaft 12 and rotating about the rotation axis Rx, the driven sprocket 21 fixed to the camshaft 19 and rotating about the rotation axis Xc of the camshaft 19, and the endless cam chain 22 wound around the drive sprocket 18 and the driven sprocket 21. The rotation of the crankshaft 12 is transmitted to the camshaft 19 by the movement of the cam chain 22. The cam chain 22 is tensioned in a region pulled from the driven sprocket 21 toward the drive sprocket 18, and is relaxed in a region returned from the drive sprocket 18 to the driven sprocket 21.

The valve train 17 includes a tension guide 23 that contacts the cam chain 22 on the tension side of the cam chain 22, and a tensioner 24 that contacts the cam chain 22 on the slack side of the cam chain 22 and applies tension to the cam chain 22. The tension guide 23 linearly extends along the track of the cam chain 22 on the tension side from a position outside the centrifugal direction of the driven sprocket 21 to a position outside the centrifugal direction of the drive sprocket 18. The tensioner 24 extends along the track of the cam chain 22 on the slack side from a position outside the centrifugal direction of the drive sprocket 18 to a position outside the centrifugal direction of the driven sprocket 21. Tensioner 24 is bent by bulging to the track of cam chain 22 on the tensioning side. The pressing force acts on the cam chain 22 on the slack side from the tensioner 24 toward the track of the cam chain 22 on the tension side. The tension determined by the cam chain 22 on the slack side can be maintained by the urging force applied from the tensioner 24.

The tensioner 24 is swingably coupled to the crankcase 13 around a swing axis Sx on the outer side of the track of the cam chain 22 on the slack side. The oscillation axis Sx is parallel to the rotation axis Rx of the crankshaft 12. The tensioner 24 is connected to a tension adjuster 25 for applying a driving force to the tensioner 24 in a wiring direction around the swing axis Sx at a position away from the swing axis Sx. The tensioner 24 can apply tension to the cam chain 22 on the slack side in response to the driving force of the tensioning regulator 25.

The tension adjuster 25 has: a housing 26 coupled to the cylinder 14, and a pushing body 28 protruding from the housing 26 so as to be movable in the direction of the axis 27 and pushing the front end of the pushing body against the tensioner 24. The axis 27 is located in the wiring direction around the swing axis Sx, intersecting the track of the cam chain 22 on the slack side. The cylinder 14 is formed with a mount 32 surrounding the mount hole 29 and receiving the housing 26 with a mount surface 31 orthogonal to the axis 27.

The housing 26 has: a thrust member 26a that closes the mounting hole 29 from the outside of the cylinder 14 and is fastened to the mount 32 by two bolts 33, and a surrounding wall 26b that extends from the thrust member 26a in the axial direction in a cylindrical shape. A bolt member 34 coaxial with the axis 27 is screwed into the thrust member 26a from the outside of the cylinder 14.

As shown in fig. 2, the tensioning device 25 of the first embodiment has a drive shaft 38, and the drive shaft 38 is rotatably supported by the thrust member 26a about the axis 27 and has an external thread 37 engraved in the shaft body 36. The drive shaft 38 has: a large-diameter shaft 41 formed of a cylindrical body coaxial with the axis 27 and accommodated in a recess 39 formed by the thrust member 26 a; and a middle diameter shaft 43 formed of a cylinder having a smaller diameter than the large diameter shaft 41 coaxially with the axis 27, coupled to the large diameter shaft 41 in the axis direction, and forming a first step surface 42 between the middle diameter shaft and the large diameter shaft 41. The shaft body 36 is formed of a cylinder having a smaller diameter than the intermediate diameter shaft 43, and is coupled to the intermediate diameter shaft 43 in the axial direction. The shaft body 36 forms a second stepped surface 44 with the intermediate diameter shaft 43. The drive shaft 38 is molded, for example, from a metallic material.

A cup washer 45 is attached to the large diameter shaft 41 of the drive shaft 38. The cup washer 45 covers the end face of the large diameter shaft 41 along the outer periphery, and covers the outer peripheral face of the large diameter shaft 41. The cup washer 45 is fitted into the recess 39 of the thrust member 26 a. The recess 39 limits displacement of the drive shaft 38 in the radial direction. The cup washer 45 is sandwiched between the thrust member 26a and the large diameter shaft 41 in the recess 39, and has a function of preventing the large diameter shaft 41 from loosening with respect to the recess 39.

A mainspring 46 is attached to the outer periphery of the intermediate diameter shaft 43 of the drive shaft 38. The clockwork spring 46 generates a spring force about the axis 27 that drives the drive shaft 38. The mainspring 46 has an elastic force for driving the drive shaft 38 in a rotation direction protruding with respect to the female screw.

The shaft 36 is provided with a pusher 28 from the front end (release end). The propulsion body 28 has: a cylinder 28a that partitions the through hole 47 coaxially with the shaft body 36, and a cap 28b that closes the through hole 47 at the release end of the cylinder 28a and pushes against the tensioner 24. The cylindrical body 28a and the cap body 28b are each molded of, for example, a metal material.

An internal thread 48 engaged with the external thread 37 of the shaft body 36 is engraved on the inner surface of the through hole 47. The thrust body 28 is constrained against relative rotation about the axis 27 with respect to the thrust member 26 a. When the drive shaft 38 rotates in accordance with the elastic force of the mainspring 46, the thrust body 28 advances in a direction away from the thrust member 26a in accordance with engagement of the male screw 37 and the female screw 48. When the drive shaft 38 rotates in the opposite direction against the elastic force of the mainspring 46, the thrust body 28 moves back toward the thrust member 26a in response to engagement of the male screw 37 and the female screw 48.

The pushing body 28 penetrates a guide 51 coupled to the peripheral wall 26b of the housing 26. The guide 51 has an opening 51a for accommodating the propulsion body 28 so as to be movable in the axial direction. As shown in fig. 3, the openings 51a are separated by a non-circular profile. Here, the opening 51a is partitioned into a cylindrical space which is partially partitioned into a plane. The opening 51a limits relative rotation of the projectile 28 about the axis 27 with respect to the guide 51. The guide 51 is molded, for example, from a metal material.

The guide 51 is formed with wrist pieces 52 extending in four directions in the radial direction. Each of the wrist pieces 52 is accommodated in a cutout 53 formed in the front end of the peripheral wall 26 b. Wrist piece 52 restricts rotation of guide 51 about axis 27. In this way, the guide 51 allows displacement of the pushing body 28 in the axial direction and serves as a check of the pushing body 28 about the axis 27. Each of the wrist pieces 52 is restrained in the cutout 53 by a C-clip 54 fitted on the outer peripheral surface of the peripheral wall 26 b.

As shown in fig. 2, the friction member 55 is received on the second step surface 44 from the axial direction. The friction member 55 is formed of an annular flat plate surrounding the shaft body 36. The friction member 55 is formed of, for example, a metal material. The friction member 55 is urged in the axial direction against the second step surface 44.

A collar member 56 is attached to the outer periphery of the thrust body 28 between the guide 51 and the friction member 55 in the axial direction. The collar member 56 is formed in a cylindrical shape surrounding the thrust body 28, and has one end 56a located closer to the friction member 55 than the thrust body 28 in the axial direction. A flange 57 that expands radially outward is formed at one end 56a of the collar member 56. The collar member 56 is molded, for example, from a resin material or a metal material.

A coil spring (elastic member) 58 is interposed between the flange 57 of the collar member 56 and the friction member 55 on the friction member 55 side in the axial direction than the thrust body 28. Since the other end 56b of the collar member 56 is restrained by the guide 51, the coil spring 58 has an elastic force that applies a pushing force to the friction member 55 in the axial direction against the thrust member 26 a. The coil spring 58 is rotatably received by the friction member 55. A boss 59 that stands up in a direction away from the thrust member 26a and restricts displacement of the coil spring 58 in the radial direction is formed on the inner periphery of the friction member 55. Here, the large diameter shaft 41 is further expanded outward than a virtual cylindrical surface 62 coaxial with the axis 27 and inscribed with the action point 61 of the coil spring 58 with respect to the friction member 55. The large diameter shaft 41 is further extended outward than a virtual cylindrical surface 63 coaxial with the axis 27 and inscribed by the coil spring 55.

A milled flat 64 is formed on the large diameter shaft 41 of the drive shaft 38 along a virtual plane including the axis 27. The thrust member 26a has a through hole 65 formed therein, which is opened in the recess 39 and closed by the plug member 34. The through hole 65 is separated into a cylindrical space coaxially with the axis 27. As shown in fig. 4, grooves 66 extending along three diametrical lines are formed around the through hole 65 on the outer surface of the thrust member 26 a.

As shown in fig. 5, the stopper 67 is inserted into the milled portion 64 from the through hole 65 before the plug member 34 is plugged. The mainspring 46 can be wound in correspondence with the rotation of the stopper 67. The mainspring 46 accumulates elastic force by winding. The stopper 67 can be fitted into the groove 66 at a specified rotational position. In this way, the rotational position of the drive shaft 38 can be restricted by the movement of the stopper 67. After the stopper 67 is removed, the through hole 65 is closed by the plug member 34.

By the action of the clockwork spring 46, a driving force is applied to the drive shaft 38 about the axis 27. When the drive shaft 38 rotates, a propulsive force is applied to the propulsion body 28 in response to engagement of the male screw 37 and the female screw 48. At this time, the friction member 55 applies resistance to the rotation of the drive shaft 38 about the axis 27 in response to the friction torque with the drive shaft 38. Similarly, large diameter shaft 41 applies resistance to rotation of drive shaft 38 about axis 27 in response to frictional torque with cup washer 45. In this way, the rotation of the drive shaft 38 is moderately restricted. Thus, the propulsive force of the propulsion body 28 is stabilized. Since the drive shaft 38 is received by the thrust member 26a by the large-diameter shaft 41 which is expanded outward from the point of action 61 of the coil spring 58 and has a larger diameter than the intermediate-diameter shaft 43 receiving the coil spring 46, the drive shaft 38 can be stably supported by the thrust member 26a. Friction torque can be generated well between the thrust member 26a and the large diameter shaft 41.

In the present embodiment, the coil spring 58 is sandwiched between the one end 56a of the collar member 56 and the friction member 55 on the friction member 55 side than the thrust body 28 in the axial direction. The collar member 58 achieves shortening of the elastic member having the urging force to the friction member 55, and achieves replacement of the long coil spring with the coil spring 58. The action of the elastic component is stabilized. Because the collar member 58 is partially replaced with an elastic member, the use of a relatively expensive elastic member can be reduced, enabling a reduction in manufacturing costs.

A boss 59 for restricting displacement of the coil spring 58 in the radial direction is formed on the friction member 55. Since the position of the coil spring 58 is set in the radial direction with respect to the friction member 55, the coil spring 58 can act on the friction member 55 with a balance force in the circumferential direction. Friction torque can be generated well between the thrust member 26a and the large diameter shaft 41.

Second embodiment

As shown in fig. 6, the tensioning device 25a of the second embodiment has a friction member 71 received on the second step surface 44 in the axial direction. The friction member 71 is formed of an annular flat plate surrounding the shaft body 36. The friction member 71 is formed of, for example, a metal material. The friction member 71 is pushed against the second step surface 44 in the axial direction.

A collar member 72 is attached to the outer periphery of the thrust body 28 between the guide 51 and the friction member 71 in the axial direction. The collar member 72 is formed in a cylindrical shape surrounding the thrust body 28, and has one end 72a located closer to the friction member 71 than the thrust body 28 in the axial direction. A flange 73 that expands radially outward is formed at one end 72a of the collar member 72. The collar member 72 is molded, for example, from a resin material or a metal material. The pusher 28 is formed with a positioning piece 74 which is inscribed in the collar member 72 and which radially restricts the displacement of the collar member 72.

An O-ring (elastic member) 75 is interposed between the flange 73 of the collar member 72 and the friction member 71 on the side of the friction member 71 in the axial direction than the thrust body 28. Since the other end 72b of the collar member 72 is restrained by the guide 51, the O-ring 75 has an elastic force that applies a pushing force to the friction member 71 in the axial direction against the thrust member 26 a. The O-ring 75 is rotatably received by the friction member 71. A boss 76 that stands up in a direction away from the thrust member 26a and restricts displacement of the O-ring 75 in the radial direction is formed on the inner periphery of the friction member 71. Here, the large diameter shaft 41 of the drive shaft 38 is further expanded to the outside than a virtual cylindrical surface 78 coaxial with the axis 27 and inscribed with the point of action 77 of the O-ring 75 with respect to the friction member 71. The large diameter shaft 41 is further extended outward than a virtual cylindrical surface 79 coaxial with the axis 27 and inscribed by the O-ring 75. The other structure is the same as the tension adjuster 25.

By the action of the clockwork spring 46, a driving force is applied to the drive shaft 38 about the axis 27. When the drive shaft 38 rotates, a propulsive force is applied to the propulsion body 28 in response to engagement of the male screw 37 and the female screw 48. At this time, the friction member 71 applies resistance to the rotation of the drive shaft 38 about the axis 27 in response to the friction torque with the drive shaft 38. Similarly, large diameter shaft 41 applies resistance to rotation of drive shaft 38 about axis 27 in response to frictional torque with cup washer 45. In this way, the rotation of the drive shaft 38 is moderately restricted. Thus, the propulsive force of the propulsion body 28 is stabilized. Since the drive shaft 38 is received by the thrust member 26a by the large diameter shaft 41 which is expanded outward from the point 77 of action of the O-ring 75 and has a larger diameter than the intermediate diameter shaft 43 receiving the mainspring 46, the drive shaft 38 can be stably supported by the thrust member 26a. Friction torque can be generated well between the thrust member 26a and the large diameter shaft 41.

In the present embodiment, the O-ring 75 is sandwiched between the one end 72a of the collar member 72 and the friction member 71 on the friction member 71 side than the thrust body 28 in the axial direction. The collar member 72 achieves shortening of the elastic member having the pressing force against the friction member 71, and achieves replacement of the elongated coil spring with the O-ring 75. The action of the elastic component is stabilized. Because the collar member 72 is partially replaced with an elastic member, the use of a relatively expensive elastic member can be reduced, enabling a reduction in manufacturing costs.

A boss 76 that restricts displacement of the O-ring 75 in the radial direction is formed on the friction member 71. Since the position of the O-ring 75 is set in the radial direction with respect to the friction member 71, the O-ring 75 can act on the friction member 71 with a balance force in the circumferential direction. Friction torque can be generated well between the thrust member 26a and the large diameter shaft 41.

Third embodiment

As shown in fig. 7, the tensioning device 25b of the third embodiment has a washer 80 attached to the outer periphery of the intermediate diameter shaft 43 and received in the axial direction by the mainspring 46. The gasket 80 is molded, for example, from a metallic material.

A collar member 81 is mounted between the guide 51 and the washer 80 in the axial direction and on the outer periphery of the thrust body 28. The collar member 81 is formed in a cylindrical shape surrounding the thrust body 28, and is sandwiched between the guide 51 and the washer 80 in the axial direction. The collar member 81 is molded, for example, from a resin material or a metal material.

A coil spring (elastic member) 82 is disposed inside the collar member 81 between the axial guide 51 and the second stepped surface 44. The coil spring 82 is sandwiched between the guide 51 and the second stepped surface 44 in a compressed state. The coil spring 82 has: a constant diameter body 82a surrounding the thrust body 28 and having a constant winding diameter, and a reduced diameter body 82b continuous with the constant diameter body 82a and having a diameter gradually decreasing toward the second step surface 44 between the thrust body 28 and the second step surface 44 in the axial direction. The coil spring 82 is received by the second stepped surface 44 by the tip end of the diameter-reduced body 82b. Here, the large diameter shaft 41 of the drive shaft 38 is further expanded outward than a virtual cylindrical surface 84 coaxial with the axis 27 and inscribed in the action point 83 of the coil spring 82 with respect to the second step surface 44. The large diameter shaft 41 is further expanded outward than a virtual cylindrical surface 85 coaxial with the axis 27 and inscribed by the coil spring 82. The other structure is the same as the tension adjuster 25.

In the tensioning regulator 25b of the present embodiment, the coil spring 82 is directly urged against the drive shaft 38, so the number of parts can be reduced as compared with the case where there are other members between the coil spring 82 and the drive shaft 38. Since the joining portions of the fittings to each other decrease as the number of the fittings decreases, the risk of failure can be reduced.

Fourth embodiment

As shown in fig. 8, the tensioning device 25c of the fourth embodiment has a collar member 91 attached to the thrust body 28 between the guide 51 and the thrust member 26 a. The collar member 91 is formed in a cylindrical shape surrounding the thrust body 28, and has one end 91a located closer to the thrust member 26a than the thrust body 28 in the axial direction. A flange 92 that expands radially outward is formed at one end 91a of the collar member 91. A cylindrical positioning piece 93 protruding toward the thrust member 26a is formed on the outer periphery of the flange 92. The collar member 91 is molded, for example, from a resin material or a metal material.

A coil spring (elastic member) 94 is sandwiched between the flange 92 of the collar member 91 and the second stepped surface 44 of the drive shaft 38 in the axial direction. Since the other end 91b of the collar member 91 is restrained by the guide 51, the coil spring 94 has an elastic force that applies a pushing force to the second stepped surface 44 in the axial direction against the thrust member 26 a. The coil spring 94 is embedded inside the positioning plate 93. The positioning piece 93 limits the displacement of the coil spring 94 in the radial direction. Here, the large diameter shaft 41 of the drive shaft 38 is further expanded to the outside than a virtual cylindrical surface 96 coaxial with the axis 27 and inscribed with the action point 95 of the coil spring 94 with respect to the second step surface 44. The large diameter shaft 41 is further outward than a virtual cylindrical surface 97 coaxial with the axis 27 and inscribed by the coil spring 94. The other structure is the same as the tension adjuster 25.

In the tensioning regulator 25c of the present embodiment, since the coil spring 94 is directly pushed against the drive shaft 38, the number of parts can be reduced as compared with the case where there are other members between the coil spring 94 and the drive shaft 38. As the number of parts decreases, the joining portions of the parts to each other decreases, so that the risk of failure can be reduced. Further, since the coil spring 94 is disposed between the collar member 91 and the drive shaft 38, the collar member 91 achieves shortening of the elastic member having a pressing force on the drive shaft 38 in the axial direction, and achieves replacement of the long coil spring with the coil spring 94. Thus, the operation of the elastic member is stabilized. Since the collar member 91 is partially replaced with an elastic member, the use of a relatively expensive elastic member can be reduced, and a reduction in manufacturing cost can be achieved.

Fifth embodiment

As shown in fig. 9, the tension adjuster 25d of the fifth embodiment has a friction member 101 received on the second step surface 44 in the axial direction. The friction member 101 is formed of an annular flat plate surrounding the shaft body 36. The friction member 101 is formed of, for example, a metal material. The friction member 101 is pushed against the second step surface 44 in the axial direction.

A collar member 102 is attached to the outer periphery of the thrust body 28 between the guide 51 and the friction member 101 in the axial direction. The collar member 102 is formed in a cylindrical shape surrounding the thrust body 28, and has one end 102a located closer to the friction member 101 than the thrust body 28 in the axial direction. The collar member 102 is molded, for example, from a resin material or a metal material. The thrust body 28 is inscribed within the collar member 102, limiting displacement of the collar member 102 in a radial direction. The collar member 102 may be in contact with the friction member 101 or the guide 51 through at least one of the one end 102a and the other end 102 b.

A coil spring (elastic member) 103 is attached to the outer periphery of the collar member 102. A coil spring (elastic member) 103 is interposed between the guide 51 and the friction member 101 in the axial direction. The coil spring 103 has an elastic force that applies a pushing force to the friction member 101 in the axial direction against the pushing member 26 a. The coil spring 103 is rotatably received by the friction member 101. Here, the large diameter shaft 41 of the drive shaft 38 is further expanded outward than the virtual cylindrical surface 105 coaxial with the axis 27 and inscribed in the action point 104 of the coil spring 103 with respect to the friction member 101. The large diameter shaft 41 is further expanded outward than a virtual cylindrical surface 106 coaxial with the axis 27 and circumscribed by the coil spring 103. The other structure is the same as the tension adjuster 25.

By the action of the clockwork spring 46, a driving force is applied to the drive shaft 38 about the axis 27. When the drive shaft 38 rotates, a propulsive force is applied to the propulsion body 28 in response to engagement of the male screw 37 and the female screw 48. At this time, the friction member 101 applies resistance to the rotation of the drive shaft 38 about the axis 27 in response to the friction torque with the drive shaft 38. Similarly, large diameter shaft 41 applies resistance to rotation of drive shaft 38 about axis 27 in response to frictional torque with cup washer 45. In this way, the rotation of the drive shaft 38 is moderately restricted. Thus, the propulsive force of the propulsion body 28 is stabilized. Since the drive shaft 38 is received by the thrust member 26a by the large diameter shaft 41 which is expanded outward from the point of action 104 of the coil spring 103 and has a larger diameter than the intermediate diameter shaft 43 receiving the mainspring 46, the drive shaft 38 can be stably supported by the thrust member 26a. Friction torque can be generated well between the thrust member 26a and the large diameter shaft 41.

Claims

1. A tensioning adjuster, the tensioning adjuster (25, 25a, 25 d) having:

A drive shaft (38) rotatably supported about an axis (27) and having an external thread (37) engraved in the shaft body (36);

a thrust member (26 a) which radially restricts displacement of the drive shaft (38) and supports an axial end of the drive shaft (38) in a thrust direction;

A thrust body (28) which is restrained against relative rotation about the axis (27) with respect to the thrust member (26 a) and which has an internal thread (48) on an inner surface thereof which engages the external thread (37);

A spring (46) that generates an elastic force for driving the drive shaft (38) about the axis (27), and that applies a propelling force to the propelling body (28) in a direction away from the thrust member (26 a) in response to engagement of the male screw (37) and the female screw (48);

friction members (55, 71) that are urged against the drive shaft (38) in the direction of an axis (27), and that generate friction between the drive shaft (38) and the friction members around the axis (27);

An elastic member (58, 75, 103) that urges the friction member (55, 71, 101) toward the thrust member (26 a) in the axial line (27) direction;

The tensioning device is characterized in that,

A large diameter shaft (41) is formed at the shaft end of the drive shaft (38), and the large diameter shaft (41) is received by the thrust member (26 a) while being expanded further outward than a virtual cylindrical surface (62, 78, 105) coaxial with the axis (27) and inscribed in the point of action of the elastic member (58, 75, 103) with respect to the friction member (55, 71, 101).

2. The tensioning device of claim 1, wherein,

Has a collar member (56, 72), the collar member (56, 72) surrounding the propulsion body (28) and having one end (56 a, 72 a) located closer to the friction member (55, 71) than the propulsion body (28) in the axial direction, the elastic member (58, 75) being sandwiched between the one end (56 a, 72 a) of the collar member (56, 72) and the friction member (55, 71) closer to the friction member (55, 71) than the propulsion body (28) in the axial direction.

3. The tensioning device of claim 2, wherein,

Bosses (59, 76) are formed on the friction members (55, 71) or the collar members (56, 72) to limit the displacement of the elastic members (58, 75) in the radial direction.

4. A tensioning device as claimed in any one of claims 1 to 3, characterized in that,

The elastic member (58, 75, 103) is provided so as to be rotatable relative to the friction member (55, 71, 101).

5. A tensioning adjuster, the tensioning adjuster (25, 25 a) having:

a thrust member (26 a) which radially restricts the displacement of the drive shaft (38) and supports the shaft end of the drive shaft (38) in a thrust direction;

Elastic members (58, 75) that bias the friction members (55, 71) toward the thrust member (26 a) in the axial direction (27);

The drive shaft (38) has: a large diameter shaft (41) which is accommodated in a recess (39) formed in the thrust member (26 a); an intermediate diameter shaft (43) which is formed of a cylinder having a smaller diameter than the large diameter shaft (41) and is coaxial with the axis (27), is coupled to the large diameter shaft (41) in the axis (27) direction, and forms a first step surface (42) with the large diameter shaft (41),

The tensioning device is characterized in that,

Has a collar member (56, 72), the collar member (56, 72) surrounding the propulsion body (28) and having one end (56 a, 72 a) located closer to the friction member (55, 71) than the propulsion body (28) in the axial direction,

The elastic member (58, 75) is sandwiched between the one end (56 a, 72 a) of the collar member (56, 72) and the friction member (55, 71) on the side closer to the friction member (55, 71) than the thrust body (28) in the axial direction.

6. The tensioning device of claim 5, wherein,

The external thread (37) is formed to have a small diameter smaller than the large diameter shaft (41).

7. The tensioning device of claim 5 or 6, wherein,

8. The tensioning device of claim 5 or 6, wherein,

9. The tensioning device of claim 7, wherein,

10. A tensioning adjuster, the tensioning adjuster (25, 25 a) having:

The tensioning device is characterized in that,

Has a collar member (56, 72), which collar member (56, 72) surrounds the propulsion body (28) and has one end (56 a, 72 a) located closer to the friction member (55, 71) than the propulsion body (28) in the axial direction,

11. A tensioning adjuster (25 c) having:

The tensioning device is characterized in that,

Has an elastic member (94), the elastic member (82, 94) being urged in the axial direction against the drive shaft (38) and applying an urging force to the drive shaft (38) against the urging member (26 a), and

A collar member (91) surrounding the thrust body (28) and being restrained against displacement in a direction away from the thrust member (26 a),

The elastic member (94) is disposed between the collar member (91) and the drive shaft (38).