CN113412380A

CN113412380A - Tensioning regulator

Info

Publication number: CN113412380A
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: 2021-09-17
Also published as: WO2020194679A1; JP7128956B2; JPWO2020194679A1

Abstract

The invention provides a tensioning regulator. The tension adjuster (25) comprises: a friction member (55) that pushes against the drive shaft (38) in the axial direction and applies resistance to rotation of the drive shaft (38) about the axis (27) in accordance with a friction torque with the drive shaft (38), and an elastic member (58) that applies a pushing force to the friction member (55) facing the thrust member (26a) in the axial direction. A large-diameter shaft (41) that extends outward beyond a virtual cylindrical surface (62) that is coaxial with the axis (27) and that is inscribed on the point of action of the elastic member (58) relative to the friction member (55) and that is received by the thrust member (26a) is formed at the shaft end of the drive shaft (38). This enables stable friction torque to be generated with respect to the drive shaft.

Description

Tensioning regulator

Technical Field

The invention relates to a tensioning device, comprising: a drive shaft rotatably supported about an axis and having a male screw engraved in a shaft body; a thrust member that restricts displacement of the drive shaft in a radial direction and supports a shaft end of the drive shaft in a thrust direction; a thrust body that is relatively restricted from relative rotation about an axis with respect to the thrust member, the thrust body having an internal thread on an inner surface thereof that engages the external thread; and a spring that generates an elastic force for driving the drive shaft around the axis and applies a propulsive force to the propulsive body in a direction away from the thrust member in accordance with the engagement of the male screw and the female screw.

Background

Patent document 1 discloses a tension adjuster having a pusher body having a female screw that engages with a male screw of a drive shaft and that advances in response to the engagement of the male screw and the female screw of the rotating drive shaft. In the tensioning device, the drive shaft is received at the shaft end by the thrust element. A stepped surface for receiving an annular plate friction member that presses against a thrust member is formed at the shaft end of the drive shaft. The friction member applies a resistance to rotation of the drive shaft about the axis in response to a frictional torque with the drive shaft. The rotation of the drive shaft is moderately restricted. Therefore, the propulsive force of the propulsive body is stabilized.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 4934816

Disclosure of Invention

Technical problem to be solved by the invention

During generation of the friction torque, the coil spring urges the friction member toward the step surface. At this time, the coil spring is pushed against the friction member radially outward of the step surface. Since 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 the friction torque cannot be achieved well. On the other hand, when a large spring load is applied to the coil spring in order to stabilize the frictional 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 that can generate a stable friction torque with respect to a drive shaft and avoid applying an excessive load to a cam chain.

Technical solution for solving technical problem

According to a first aspect of the invention, a tensioning adjuster has: a drive shaft rotatably supported about an axis and having a male screw engraved in a shaft body; a thrust member that restricts displacement of the drive shaft in a radial direction and supports a shaft end of the drive shaft in a thrust direction; a thrust body constrained against relative rotation about the axis with respect to the thrust member, having an internal thread on an inner surface thereof engaging the external thread; a spring that generates an elastic force that drives the drive shaft around the axis, and applies a propulsive force to the propulsive body in a direction away from the thrust member, corresponding to engagement of the external thread and the internal thread; a friction member that is urged against the drive shaft in an axis direction, generating a frictional force between the drive shaft and the friction member 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 expanded outward beyond a virtual cylindrical surface that is coaxial with the axis and that is inscribed in the point of action of the elastic member with respect to the friction member, and is received by the thrust member (japanese patent No. け No. められる).

According to the second aspect of the present invention, the tension adjuster has: a drive shaft rotatably supported about an axis and having a male screw engraved in a shaft body; a thrust member that restricts displacement of the drive shaft in a radial direction and supports a shaft end of the drive shaft in a thrust direction; a thrust body constrained against relative rotation about the axis with respect to the thrust member, having an internal thread on an inner surface thereof engaging the external thread; a spring that generates an elastic force that drives the drive shaft around the axis, and applies a propulsive force to the propulsive body in a direction away from the thrust member, corresponding to engagement of the external thread and the internal thread; a friction member that is urged against the drive shaft in an axis direction, generating a frictional force between the drive shaft and the friction member around the axis; and an elastic member that urges the friction member toward the thrust member in the axial direction. In the tension adjuster, the drive shaft includes: a large diameter shaft accommodated in a recess formed in the thrust member; and a middle diameter shaft which is formed by a cylinder body which is coaxial with the axis and has a smaller diameter than the large diameter shaft, is combined with the large diameter shaft in the axis direction, and forms a first step surface between the middle diameter shaft and the large diameter shaft.

According to the third side surface, the male screw is formed with a small diameter smaller than the large diameter shaft, in addition to the structure of the second side surface.

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

According to a fifth aspect, in addition to any one of the configurations of the first to fourth aspects, the tension adjuster has a collar member that surrounds the thrust body and has one end located closer to the friction member than the thrust 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 than the thrust body in the axial direction.

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

According to a seventh aspect of the present invention, a tension adjuster has: a drive shaft rotatably supported about an axis and having a male screw engraved in a shaft body; a thrust member that restricts displacement of the drive shaft in a radial direction and supports a shaft end of the drive shaft in a thrust direction; a thrust body constrained against relative rotation about the axis with respect to the thrust member, having an internal thread on an inner surface thereof engaging the external thread; a spring that generates an elastic force that drives the drive shaft around the axis, and applies a propulsive force to the propulsive body in a direction away from the thrust member, corresponding to engagement of the external thread and the internal thread; a friction member that is urged against the drive shaft in an axis direction, generating a frictional force between the drive shaft and the friction member around the axis; and an elastic member that urges the friction member toward the thrust member in the axial direction. In the tension adjuster, a collar member is provided which surrounds the thrust body and has one end located closer to the friction member side than the thrust 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 thrust body in the axial direction.

According to an eighth aspect of the present invention, a tension adjuster has: a drive shaft rotatably supported about an axis and having a male screw engraved in a shaft body; a thrust member that restricts displacement of the drive shaft in a radial direction and supports a shaft end of the drive shaft in a thrust direction; a thrust body constrained against relative rotation about the axis with respect to the thrust member, having an internal thread on an inner surface thereof engaging the external thread; a spring that generates an elastic force around the axis to drive the drive shaft, and applies a propulsive force to the propulsive body in a direction away from the thrust member in response to engagement of the external thread and the internal thread. In the tension adjuster, there is an elastic member that is urged against the drive shaft in the axial direction, and that applies an urging force to the drive shaft facing the thrust member.

According to a ninth aspect, in addition to the configuration of the eighth aspect, the tension adjuster has a collar member surrounding the thrust body and 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 a first side, the driving force is applied to the drive shaft around the axis by the action of a spring. When the drive shaft rotates, a propulsive force is applied to the propulsive body corresponding to the engagement of the external threads and the internal threads. At this time, the friction member applies resistance to rotation of the drive shaft about the axis in accordance with the friction torque with the drive shaft. The rotation of the drive shaft is moderately restricted. Therefore, the propulsive force of the propulsive body is stabilized. Since the drive shaft is received by the thrust member by the large diameter shaft extending outward beyond the operating point of the elastic member, the drive shaft can be stably supported by the thrust member. The friction torque can be generated favorably between the thrust member and the large-diameter shaft.

According to the second side, the driving force is applied to the drive shaft around the axis by the action of a spring. When the drive shaft rotates, a propulsive force is applied to the propulsive body corresponding to the engagement of the external threads and the internal threads. At this time, the friction member applies resistance to rotation of the drive shaft about the axis in accordance with the friction torque with the drive shaft. The rotation of the drive shaft is moderately restricted. Therefore, the propulsive force of the propulsive body is stabilized. Since the drive shaft is received by the thrust member by the large diameter shaft extending outward from the middle diameter shaft, the drive shaft can be stably supported by the thrust member. The friction torque can be generated favorably between the thrust member and the large-diameter shaft.

According to the third aspect, since the male screw is formed with a small diameter smaller than the large diameter shaft, the drive shaft can be stably supported by the thrust member.

According to the fourth side, relative rotation is allowed between the elastic member and the friction member, and therefore, the elastic member can be prevented from twisting. The elastic member can accurately apply an elastic force to the friction member.

According to the fifth aspect, the collar member can realize shortening of the elastic member in the axial direction. Therefore, the operation of the elastic member can be stabilized. Since the collar member is partially replaced with the elastic member, the use of a relatively expensive elastic member can be reduced, achieving a reduction in manufacturing cost.

According to the sixth aspect, 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. The friction torque can be generated favorably between the thrust member and the large-diameter shaft.

According to the seventh aspect, the collar member can realize shortening of the elastic member in the axial direction. Therefore, the operation of the elastic member can be stabilized. Since the collar member is partially replaced with the elastic member, the use of a relatively expensive elastic member can be reduced, achieving a reduction in manufacturing cost.

According to the eighth aspect, since the elastic member is directly urged against the drive shaft, the number of fittings can be reduced as compared with a case where other members are present between the elastic member and the drive shaft. As the number of components is reduced, the connecting portion between the components is reduced, and therefore, the risk of failure can be reduced.

According to the ninth aspect, the collar member can realize shortening of the elastic member in the axial direction. Therefore, the operation of the elastic member can be stabilized. Since the collar member is partially replaced with the elastic member, the use of a relatively expensive elastic member can be reduced, achieving a reduction in manufacturing cost.

Drawings

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

Fig. 2 is an enlarged cross-sectional view of the tension adjuster of the first embodiment as viewed from a cutting plane including the shaft center (first embodiment).

Fig. 3 is a sagittal view of an arrow 3 of fig. 2 (first embodiment).

Fig. 4 is a sagittal view of an arrow 4 of fig. 2 (first embodiment).

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

Fig. 6 is an enlarged sectional view of the tension adjuster of the second embodiment (second embodiment) as viewed from a cutting plane including the shaft center.

Fig. 7 is an enlarged sectional view of the tension adjuster of the third embodiment as viewed from a cutting plane including the shaft center (third embodiment).

Fig. 8 is an enlarged cross-sectional view of the tension adjuster of the fourth embodiment as viewed from a cutting plane including the shaft center (fourth embodiment).

Fig. 9 is an enlarged cross-sectional view of the tension adjuster of the fifth embodiment as viewed from a cutting plane including the shaft center (fifth embodiment).

Description of the reference numerals

25 tensioning the adjuster; 25a tensioning adjuster; 25b a tensioning adjuster; 25c a tensioning adjuster; 26a thrust member; 27 axes; 28a projectile body; 36 shaft bodies; 37 external threads; 38 a drive shaft; 41 a large diameter shaft; 43 a medium diameter shaft; 46 springs (power spring); 48 internal threads; 55 a friction member; 56a collar member; 56a at one end; 58 elastic member (coil spring); 59 a boss; 62 virtual cylindrical surface; 71 a friction member; 72a collar member; 72a at one end; 75 resilient members (O-rings); 76 bosses; 78 virtual cylindrical surface; 82 elastic members (coil springs); 91a collar member; 94 elastic member (coil spring); 101 a friction member; 103 an elastic member (coil spring); 105 virtual cylindrical surfaces.

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

First embodiment

Fig. 1 schematically shows an internal combustion engine according to an embodiment of the present invention. The internal combustion engine 11 includes: a crankcase 13 that supports the crankshaft 12 rotatably about a rotation axis Rx, a cylinder 14 that is coupled to the crankcase 13 and guides a linear reciprocating motion of a piston coupled to the crankshaft 12 by a connecting rod, a cylinder head 15 that is coupled to the cylinder 14 and partitions a combustion chamber between the piston and the cylinder head, and a head cover 16 that is coupled to the cylinder head 15 and houses a valve mechanism that controls opening/closing of an intake valve and an exhaust valve facing the combustion chamber. When the intake valve is opened as the piston descends, the mixture is introduced into the combustion chamber. When the intake valve closes and the piston rises, the mixture is compressed in the combustion chamber. When the mixed gas is ignited in the combustion chamber, the mixed gas is burned, and the volume of the combustion chamber is enlarged. Exhaust gas is exhausted from the combustion chamber when the piston is lowered and then the exhaust valve is opened as the piston is raised. Thus, power is taken from the crankshaft 12.

A valve train 17 that realizes opening/closing operations of an intake valve and an exhaust valve at predetermined timings in conjunction with linear reciprocation of a piston is incorporated in the internal combustion engine 11. The valve mechanism 17 has: a drive sprocket 18 fixed to the crankshaft 12 and rotating about the rotation axis Rx, a driven sprocket 21 fixed to the camshaft 19 and rotating about the rotation axis Xc of the camshaft 19, and an 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 drawn from the driven sprocket 21 toward the drive sprocket 18, and slackened in a region returned from the drive sprocket 18 to the driven sprocket 21.

The valve mechanism 17 is combined with 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 from a position on the outer side in the centrifugal direction of the driven sprocket 21 to a position on the outer side in the centrifugal direction of the drive sprocket 18 along the track of the tension-side cam chain 22. The tensioner 24 extends from a position on the centrifugal direction outer side of the drive sprocket 18 to a position on the centrifugal direction outer side of the driven sprocket 21 along the track of the slack side cam chain 22. The tensioner 24 bulges and bends toward the track of the cam chain 22 on the tension side. The urging force acts on the slack-side cam chain 22 from the tensioner 24 toward the track of the tension-side cam chain 22. By the action of the pressing force applied from the tensioner 24, the tension determined by the slack-side cam chain 22 can be maintained.

The tensioner 24 is coupled to the crankcase 13 so as to be swingable about a swing axis Sx outside the track of the slack side cam chain 22. The swing axis Sx is parallel to the rotation axis Rx of the crankshaft 12. A tension adjuster 25 that applies a driving force to the tensioner 24 in the wire connecting direction around the swing axis Sx is connected to the tensioner 24 at a position away from the swing axis Sx. The tensioner 24 can apply tension to the slack side cam chain 22 corresponding to the driving force of the tension adjuster 25.

The tension adjuster 25 has: a housing 26 coupled to the cylinder 14, and a pusher 28 projecting from the housing 26 in the direction of the axis 27 so as to be movable and pushing the front end of the pusher against the tensioner 24. The axis 27 is located in the wire connecting direction around the swing axis Sx, crossing the trajectory of the cam chain 22 on the slack side. The cylinder 14 is formed with a mounting seat 32 surrounding the mounting hole 29 and receiving the housing 26 with a seat 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 mounting seat 32 by two bolts 33, and a surrounding wall 26b that extends in a cylindrical shape in the axial direction from the thrust member 26 a. 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 tension adjuster 25 of the first embodiment includes a drive shaft 38, and the drive shaft 38 is supported rotatably about an axis 27 by a thrust member 26a and has a male screw 37 engraved on a shaft body 36. The drive shaft 38 has: a large-diameter shaft 41, formed by a cylindrical body coaxial with the axis 27, housed in the recess 39 formed by the thrust member 26 a; the intermediate diameter shaft 43 is formed coaxially with the axis 27 by a cylindrical body having a smaller diameter than the large diameter shaft 41, is coupled to the large diameter shaft 41 in the axial direction, and forms a first step surface 42 with the large diameter shaft 41. The shaft body 36 is formed of a cylindrical body 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 step surface 44 with the intermediate diameter shaft 43. The drive shaft 38 is formed of, for example, a metal 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 surface of the large-diameter shaft 41 along the outer periphery, and covers the outer peripheral surface 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 radially restricts displacement of the drive shaft 38. 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 spring 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 clockwork spring 46 has an elastic force that drives the drive shaft 38 in a rotational direction protruding with respect to the internal thread.

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

An internal thread 48 that engages with the external thread 37 of the shaft body 36 is engraved on the inner surface of the through hole 47. The projectile 28 is restricted from relative rotation about the axis 27 with respect to the thrust member 26 a. When the drive shaft 38 rotates corresponding to the elastic force of the clockwork spring 46, the projectile 28 advances in a direction away from the thrust member 26a corresponding to the engagement of the external thread 37 and the internal thread 48. When the drive shaft 38 rotates in the reverse direction against the elastic force of the spring 46, the thrust body 28 moves back close to the thrust member 26a in accordance with the engagement of the male screw 37 and the female screw 48.

The pusher 28 passes through the guide 51 coupled to the peripheral wall 26b of the housing 26. The guide 51 has an opening 51a for accommodating the pusher 28 so as to be movable in the axial direction. As shown in fig. 3, the openings 51a are separated by a non-circular contour. The opening 51a defines a space having a cylindrical shape with a flat partial section. The opening 51a limits relative rotation of the projectile 28 about the axis 27 relative to the guide 51. The guide 51 is molded from, for example, a metal material.

The guide 51 is formed with wrist pieces 52 extending in four radial directions. Each wrist piece 52 is received in a cutout 53 formed in the front end of the peripheral wall 26 b. Wrist tab 52 limits rotation of guide 51 about axis 27. In this way, the guide 51 allows displacement of the projectile 28 in the axial direction and acts as a backstop for the projectile 28 about the axis 27. Each wrist piece 52 is confined within the notch 53 by a C-clip 54 mounted 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 stepped 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 pushes against the second step surface 44 in the axial direction.

A collar member 56 is attached to the outer periphery of the propelling 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 is formed at one end 56a of the collar member 56 so as to expand radially outward. The collar member 56 is molded from, for example, a resin material or a metal material.

The collar member 56 is closer to the friction member 55 than the pusher 28 in the axial direction, and a coil spring (elastic member) 58 is interposed between the flange 57 of the collar member 56 and the friction member 55. Since the other end 56b of the collar member 56 is restricted by the guide 51, the coil spring 58 has an elastic force that applies an urging force to the friction member 55 in the axial direction facing the thrust member 26 a. The coil spring 58 is relatively rotatably received in the friction member 55. A boss 59 standing in a direction away from the thrust member 26a and restricting 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 expanded outward beyond a virtual cylindrical surface 62 which is coaxial with the axis 27 and which is inscribed in the operating point 61 of the coil spring 58 with respect to the friction member 55. The large diameter shaft 41 is extended outward from a virtual cylindrical surface 63 coaxial with the axis 27 and inscribed by the coil spring 55.

A mill flat portion 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 that opens into the recess 39 and is closed by the plug member 34. The through hole 65 is partitioned into a cylindrical space coaxially with the axis 27. As shown in fig. 4, groove portions 66 extending on three radial lines are formed on the outer surface of the thrust member 26a around the through hole 65.

As shown in fig. 5, before the plug member 34 is plugged, the stopper 67 is inserted into the milled flat portion 64 from the through hole 65. The clockwork spring 46 can be wound corresponding to the rotation of the stopper 67. The spring 46 accumulates elastic force by winding. The stopper 67 can be fitted into the groove portion 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.

A driving force is applied to the drive shaft 38 about the axis 27 by the action of a clockwork spring 46. When drive shaft 38 is rotated, a propulsive force is applied to projectile 28 in response to the engagement of external threads 37 and internal threads 48. At this time, the friction member 55 applies resistance to rotation of the drive shaft 38 about the axis 27 in accordance with the friction torque with the drive shaft 38. Likewise, large diameter shaft 41 applies a resistance to rotation of drive shaft 38 about axis 27 corresponding to the frictional torque with cup washer 45. In this way, the rotation of the drive shaft 38 is moderately restricted. Therefore, the propulsive force of the propulsive 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 beyond the operating point 61 of the coil spring 58 and has a larger diameter than the middle diameter shaft 43 receiving the spring 46, the drive shaft 38 can be stably supported by the thrust member 26 a. The friction torque can be generated favorably between the thrust member 26a and the large-diameter shaft 41.

In the present embodiment, the coil spring 58 is sandwiched between one end 56a of the collar member 56 and the friction member 55 on the side closer to the friction member 55 than the pushing body 28 in the axial direction. The collar member 58 achieves shortening of the elastic member having the urging force against the friction member 55, and achieves replacement of the elongated coil spring with the coil spring 58. The operation of the elastic member 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, achieving a reduction in manufacturing costs.

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

Second embodiment

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

A collar member 72 is mounted on the outer periphery of the propelling 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 from, for example, a resin material or a metal material. A positioning piece 74 that is inscribed in the collar member 72 and limits displacement of the collar member 72 in the radial direction is formed in the pusher body 28.

The collar member 72 is closer to the friction member 71 than the pusher 28 in the axial direction, and an O-ring (elastic member) 75 is interposed between the flange 73 of the collar member 72 and the friction member 71. Because the other end 72b of the collar member 72 is restricted by the guide 51, the O-ring 75 has an elastic force that applies an urging force to the friction member 71 in the axial direction facing the thrust member 26 a. The O-ring 75 is relatively rotatably received in the friction member 71. A boss 76 standing in a direction away from the thrust member 26a and restricting 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 expanded outward beyond a virtual cylindrical surface 78 which is coaxial with the axis 27 and which is inscribed on the O-ring 75 with respect to the operating point 77 of the friction member 71. The large diameter shaft 41 is extended outward from 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.

A driving force is applied to the drive shaft 38 about the axis 27 by the action of a clockwork spring 46. When drive shaft 38 is rotated, a propulsive force is applied to projectile 28 in response to the engagement of external threads 37 and internal threads 48. At this time, the friction member 71 applies resistance to the rotation of the drive shaft 38 about the axis 27 in accordance with the friction torque with the drive shaft 38. Likewise, large diameter shaft 41 applies a resistance to rotation of drive shaft 38 about axis 27 corresponding to the frictional torque with cup washer 45. In this way, the rotation of the drive shaft 38 is moderately restricted. Therefore, the propulsive force of the propulsive 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 beyond the operating point 77 of the O-ring 75 and has a larger diameter than the middle diameter shaft 43 receiving the spring 46, the drive shaft 38 can be stably supported by the thrust member 26 a. The friction torque can be generated favorably 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 side closer to the friction member 71 than the thrust body 28 in the axial direction. The collar member 72 realizes shortening of the elastic member having the pressing force against the friction member 71, and realizes replacement of the elongated coil spring with the O-ring 75. The operation of the elastic member is stabilized. Because the collar member 72 is partially replaced with the elastic member, the use of a relatively expensive elastic member can be reduced, achieving a reduction in manufacturing cost.

The friction member 71 is formed with a boss 76 that radially restricts displacement of the O-ring 75. 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. The friction torque can be generated favorably between the thrust member 26a and the large-diameter shaft 41.

Third embodiment

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

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

A coil spring (elastic member) 82 is disposed inside the collar member 81 and between the guide 51 and the second stepped surface 44 in the axial direction. The coil spring 82 is sandwiched between the guide 51 and the second step surface 44 in a compressed state. The coil spring 82 has: the constant diameter body 82a having a constant winding diameter and surrounding the pusher 28, and the diameter reducing body 82b continuous with the constant diameter body 82a and having a diameter gradually reduced toward the second step surface 44 between the pusher 28 and the second step surface 44 in the axial direction. The coil spring 82 is received by the second stepped surface 44 at the tip end of the reducing body 82 b. Here, the large diameter shaft 41 of the drive shaft 38 is expanded outward beyond a virtual cylindrical surface 84 that is coaxial with the axis 27 and that is inscribed in an action point 83 of the coil spring 82 with respect to the second stepped surface 44. The large diameter shaft 41 is extended outward from 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 adjuster 25b of the present embodiment, the coil spring 82 is directly pushed against the drive shaft 38, so the number of parts can be reduced as compared with a case where other members are present between the coil spring 82 and the drive shaft 38. Since the coupling portion of the fittings to each other is reduced as the number of fittings is reduced, the risk of failure can be reduced.

Fourth embodiment

As shown in fig. 8, the tension adjuster 25c according to the fourth embodiment includes a collar member 91 attached to the pusher 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 from, for example, a resin material or a metal material.

A coil spring (elastic member) 94 is interposed between the flange 92 of the collar member 91 and the second step surface 44 of the drive shaft 38 in the axial direction. Since the other end 91b of the collar member 91 is restricted by the guide 51, the coil spring 94 has an elastic force that applies an urging force to the second step surface 44 in the axial direction against the thrust member 26 a. The coil spring 94 is embedded inside the positioning piece 93. The positioning piece 93 restricts the displacement of the coil spring 94 in the radial direction. Here, the large diameter shaft 41 of the drive shaft 38 is expanded outward beyond a virtual cylindrical surface 96 that is coaxial with the axis 27 and that is inscribed in an action point 95 of the coil spring 94 with respect to the second stepped surface 44. The large-diameter shaft 41 is positioned 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 adjuster 25c of the present embodiment, since the coil spring 94 is directly urged against the drive shaft 38, the number of parts can be reduced as compared with the case where other parts are present between the coil spring 94 and the drive shaft 38. As the number of the fittings is reduced, the coupling portions of the fittings to each other are reduced, 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 realizes shortening of the elastic member having the urging force against the drive shaft 38 in the axial direction, and realizes replacement of the elongated coil spring with the coil spring 94. Therefore, the operation of the elastic member is stabilized. Since the collar member 91 is partially replaced with the elastic member, the use of a relatively expensive elastic member can be reduced, achieving a reduction in manufacturing cost.

Fifth embodiment

As shown in fig. 9, the tension adjuster 25d of the fifth embodiment includes a friction member 101 received on the second stepped surface 44 from 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 pushes against the second step surface 44 in the axial direction.

A collar member 102 is mounted on the outer periphery of the propelling 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 from, for example, a resin material or a metal material. The projectile 28 is inscribed within the collar member 102 and radially limits the displacement of the collar member 102. 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 an urging force to the friction member 101 in the axial direction facing the thrust member 26 a. The coil spring 103 is relatively rotatably received in the friction member 101. Here, the large diameter shaft 41 of the drive shaft 38 is expanded outward beyond the virtual cylindrical surface 105 which is coaxial with the axis 27 and which is inscribed in the coil spring 103 with respect to the operating point 104 of the friction member 101. The large diameter shaft 41 is extended outward from 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.

A driving force is applied to the drive shaft 38 about the axis 27 by the action of a clockwork spring 46. When drive shaft 38 is rotated, a propulsive force is applied to projectile 28 in response to the engagement of external threads 37 and internal threads 48. At this time, the friction member 101 applies resistance to rotation of the drive shaft 38 about the axis 27 in accordance with the friction torque with the drive shaft 38. Likewise, large diameter shaft 41 applies a resistance to rotation of drive shaft 38 about axis 27 corresponding to the frictional torque with cup washer 45. In this way, the rotation of the drive shaft 38 is moderately restricted. Therefore, the propulsive force of the propulsive 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 beyond the operating point 104 of the coil spring 103 and has a larger diameter than the middle diameter shaft 43 receiving the spring 46, the drive shaft 38 can be stably supported by the thrust member 26 a. The friction torque can be generated favorably between the thrust member 26a and the large-diameter shaft 41.

The claims (modification according to treaty clause 19)

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

a drive shaft (38) rotatably supported around the axis (27) and having a male screw (37) engraved in the shaft body (36);

a thrust member (26a) that limits displacement of the drive shaft (38) in the radial direction and supports the shaft end of the drive shaft (38) in the thrust direction;

a thrust body (28) constrained against relative rotation about said axis (27) with respect to said thrust member (26a), having, on an inner surface, an internal thread (48) meshing with said external thread (37);

a spring (46) that generates an elastic force that drives the drive shaft (38) around the axis (27), and that applies a propulsive force to the propulsive body (28) in a direction away from the thrust member (26a) in response to engagement of the external thread (37) and the internal thread (48);

a friction member (55, 71) urged against the drive shaft (38) in the direction of an axis (27), generating a frictional force with the drive shaft (38) around the axis (27);

an elastic member (58, 75, 103) that urges the friction member (55, 71, 101) toward the thrust member (26a) in the direction of the axis (27);

the tensioning device is characterized in that it is provided with,

a large-diameter shaft (41) is formed at the shaft end of the drive shaft (38), and the large-diameter shaft (41) is expanded outward beyond virtual cylindrical surfaces (62, 78, 105) that are coaxial with the axis (27) and that are inscribed in the points of action of the elastic members (58, 75, 103) with respect to the friction members (55, 71, 101), and is received by the thrust member (26 a).

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

an elastic member (58, 75) that urges the friction member (55, 71) toward the thrust member (26a) in the direction of the axis (27);

the drive shaft (38) has: a large-diameter shaft (41) accommodated in a recess (39) formed in the thrust member (26 a); a middle diameter shaft (43) formed of a cylindrical body having a diameter smaller than that of the large diameter shaft (41) and coaxial with the axis (27), coupled to the large diameter shaft (41) in the direction of the axis (27), and forming a first step surface (42) with the large diameter shaft (41),

the tensioning device is characterized in that it is provided with,

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

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

3. The tension adjuster as set forth in claim 2,

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

4. The tension adjuster of claim 1,

has a collar member (56, 72) that surrounds the thrust body (28) and has one end (56a, 72a) that is located closer to the friction member (55, 71) than the thrust body (28) in the axial direction, the elastic member (58, 75) being sandwiched between the one end (56a, 72a) of the collar member (56, 72) and the friction member (55, 71) that are closer to the friction member (55, 71) than the thrust body (28) in the axial direction.

5. A tensioning adjuster according to any one of claims 2 to 4,

a projection (59, 76) for restricting the displacement of the elastic member (58, 75) in the radial direction is formed on the friction member (55, 71) or the collar member (56, 72).

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

the tensioning device is characterized in that it is provided with,

7. A tensioning adjuster, the tensioning adjuster (25c) having:

the tensioning device is characterized in that it is provided with,

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

a collar member (91) surrounding the propelling body (28) and being restricted from being displaced in a direction away from the thrust member (26a),

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

8. A tensioning device according to one of claims 1 to 5,

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

Claims

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

the tensioning device is characterized in that it is provided with,

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

a friction member (55, 71, 101) urged against the drive shaft (38) in a direction of an axis (27), generating a frictional force with the drive shaft (38) around the axis (27);

the tensioning device is characterized in that it is provided with,

the drive shaft (38) has: a large-diameter shaft (41) accommodated in a recess (39) formed in the thrust member (26 a); and a middle diameter shaft (43) which is formed by a cylinder body which is coaxial with the axis (27) and has a smaller diameter than the large diameter shaft (41), is combined with the large diameter shaft (41) in the direction of the axis (27), and forms a first step surface (42) between the middle diameter shaft and the large diameter shaft (41).

3. The tension adjuster as set forth in claim 2,

4. A tensioning device according to one of claims 1 to 3,

5. A tensioning adjuster according to any one of claims 1 to 4,

6. The tension adjuster of claim 5,

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

the tensioning device is characterized in that it is provided with,

8. A tensioning adjuster, the tensioning adjuster (25b, 25c) having:

the tensioning device is characterized in that it is provided with,

has an elastic member (82, 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) facing the thrust member (26 a).

9. The tension adjuster as set forth in claim 7,

the thrust device is provided with a collar member (91) which surrounds the thrust body (28) and is restricted from being displaced in a direction away from the thrust member (26a), and the elastic member (94) is arranged between the collar member (91) and the drive shaft (38).