JP2008223792A - Tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure for stably thrusting a second shaft member. <P>SOLUTION: An inside first shaft member 3 and an outside second shaft member 4 threadedly engaged by screw parts 8 and 10, and an energizing spring 6 rotatingly energizing the first shaft member 3 in one direction, are stored in a case 2, and rotational energizing force of the energizing spring 6 is converted into thrust of the second shaft member 4 by restricting rotation of the second shaft member 4. The first shaft member 3 rotates in a state in direct or indirect contact with the case 2, and a friction member 6 generating friction torque between the member and the first shaft member 3 is arranged so as to contact with the first shaft member 3, and an elastic member 7 is arranged outside in the radial direction of the second shaft member 4. The elastic member 7 stabilizes thrust of the second shaft member 4 by energizing the friction member 6 in the direction contacting with the first shaft member 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tensioner that maintains a constant tension of an endless belt or chain.

  The tensioner, for example, pushes a timing chain or timing belt used in an automobile engine with a predetermined force, and acts to keep the tension constant when the chain is stretched or loosened.

  FIG. 18 shows a state in which the tensioner 100 is mounted on the engine body 200 of the automobile. A pair of cam sprockets 210 and 210 and a crank sprocket 220 are arranged inside the engine body 200, and the timing chain 230 is stretched between the sprockets 210, 210 and 220 in an endless manner. A chain guide 240 is swingably disposed on the moving path of the timing chain 230, and the timing chain 230 slides on the chain guide 240. An attachment surface 250 is formed on the engine body 200, and the tensioner 100 is fixed to the attachment surface 250 by a bolt 270 that passes through the attachment hole 260 of the attachment surface 250. Although illustration is omitted, lubricating oil is sealed inside the engine body 200.

  19 and 20 show a tensioner 100 that is generally used, and a rotating shaft 120 and a propulsion shaft 130 are assembled and arranged inside the case 110. The case 110 has a main body portion 111 extending in the axial direction for inserting the shafts 120 and 130, and a flange portion 112 extending from the main body portion 111 in a direction crossing the axial direction. The flange portion 112 attaches the tensioner 100 to the engine main body 200. For this reason, the flange portion 112 is formed with an attachment hole 113 through which a bolt screwed into the engine main body 200 passes. The main body 111 accommodates each component to be described later. For this reason, a housing hole 114 having the same diameter is formed along the axial direction.

  The rotation shaft 120 and the propulsion shaft 130 are assembled by forming a male screw portion 121 on the outer surface of the rotation shaft 120 and forming a female screw portion 131 on the inner surface of the propulsion shaft 130 and screwing these screw portions 121 and 131 together. Is done by. A receiving seat 140 is provided inside the case 110 corresponding to the proximal end of the rotating shaft 120 so as to be positioned in the accommodation hole 114, and the receiving shaft 140 allows the proximal end of the rotating shaft 120 to be located. It is supported. In the assembled state, the propulsion shaft 130 is screwed into a substantially half portion on the front side of the rotary shaft 120, and a biasing spring 150 made of a torsion spring is arranged in a substantially half portion on the rear side where the propulsion shaft 130 is not screwed. Has been.

  The biasing spring 150 has a hook portion 151 at one end inserted into and locked with a slit 123 formed at the base end portion of the rotating shaft 120, and a hook portion 152 at the other end locked in the case 110. Therefore, when the biasing spring 150 is twisted and assembled with a predetermined torque applied, the rotating shaft 120 is rotated by the biasing force of the biasing spring 150.

  A bearing 160 is fixed to the front end portion of the case 110 by a retaining ring 170, and the propulsion shaft 130 passes through the sliding hole 161 of the bearing 160. The inner surface of the sliding hole 161 of the bearing 160 and the outer surface of the propulsion shaft 130 are formed in a substantially oval shape, a parallel cut, or other non-circular shape, whereby the propulsion shaft 130 is in a state in which rotation is restricted. .

  The bearing 160 is formed into a flat plate shape having a predetermined thickness, and a plurality of fixed pieces 162 are formed on the outer peripheral side. Then, the fixed piece 162 is fitted into the notch groove 115 formed at the tip portion of the case 110, so that the entire bearing 160 is prevented from rotating. Since the bearing 160 is thus prevented from rotating with respect to the case 110, the propulsion shaft 130 penetrating the bearing 160 is rotationally restrained by the case 110 via the bearing 160. The case 110 moves forward and backward.

  A cap 180 is attached to the tip of the propulsion shaft 130, and the cap 180 is in contact with the chain guide 240 in the engine main body 200 described above.

  A spacer 190 is disposed inside the case 110. The spacer 190 has a cylindrical shape extending in the axial direction (propulsion direction) while surrounding the periphery of the rotary shaft 120 and the propulsion shaft 130, and the shafts 120 and 130 in a screwed state come out of the tip portion of the case 110. To prevent that. In order to prevent this from coming off, the rotary shaft 120 is formed into a hooked shape that can be abutted against the spacer 190.

  In the tensioner 100 having the above structure, the rotating shaft 120 is rotated by the biasing force of the biasing spring 150, and this rotating force is converted into the propulsive force of the propulsion shaft 130. Therefore, the propulsion shaft 130 advances. As a result, the propulsion shaft 130 presses the timing chain 230 via the cap 180 and the chain guide 240, so that tension can be applied to the timing chain 230.

  In the tensioner 100 shown in FIGS. 19 and 20, the rotating shaft 120 that is urged by the urging spring 150 may slide and rotate, or may rotate in a fine forward / reverse direction. There is a problem that the propulsion shaft 130 performs an unstable forward / backward movement due to an unstable rotational behavior. In order to prevent such an unstable rotational behavior of the rotating shaft 120, conventionally, tensioners described in JP-A-2005-180661 and JP-A-2003-184968 have been developed.

  The tensioner disclosed in Japanese Patent Application Laid-Open No. 2005-180661 forms a hook-shaped presser ring on the rotating shaft, and presses the presser ring facing the presser ring with a gap between the presser rings. A compression spring is arranged between them. The compression spring is disposed in a compressed state so as to be extrapolated to the rotating shaft. As a result, the compression spring is urged so that the shaft end portion of the rotary shaft is in close contact with the case via the presser ring. By this biasing, the rotating shaft has a good friction torque and is in close contact with the case, so that unstable rotating behavior of the rotating shaft can be prevented.

The tensioner disclosed in Japanese Patent Laid-Open No. 2003-184968 arranges a compression spring between a rotary shaft and a propulsion shaft in a compressed state. The compression spring is disposed so that both ends thereof are in contact with the rotation shaft and the propulsion shaft in a state where the compression spring is extrapolated to the rotation shaft. In this structure, since a friction torque is generated between the compression spring and the rotary shaft, unstable friction behavior of the rotary shaft is prevented by this friction torque.
JP 2005-180661 A JP 2003-184968 A

  In the tensioners disclosed in JP-A-2005-180661 and JP-A-2003-184968, unstable rotation behavior of the rotating shaft is prevented, so that the propulsion shaft advances and retreats stably. On the other hand, depending on the type of engine, a tensioner that can prevent the unstable rotational behavior of the rotating shaft more strongly and stably advance and retract the propelling shaft, thereby ensuring a stable behavior is required.

  The present invention has been made to meet such a demand, and an object thereof is to provide a tensioner capable of ensuring a stable behavior.

  The tensioner according to the first aspect of the present invention includes an inner first shaft member and an outer second shaft member that are screwed together by a threaded portion, and a biasing spring that rotationally biases the first shaft member in one direction. Is a tensioner that restrains the rotation of the second shaft member and converts the rotation biasing force of the biasing spring into the propulsion force of the second shaft member, wherein the first shaft member is The shaft end portion rotates in a state of being in direct or indirect contact with the case, and a friction member that generates a friction torque with the first shaft member is provided so as to be in contact with the first shaft member, An elastic member is provided on a radially outer side of the second shaft member, and this elastic member biases the friction member in a direction in contact with the first shaft member.

  In the first aspect of the present invention, frictional torque is generated between the friction member and the first shaft member by contacting the first shaft member. Since the elastic member urges the friction member in a direction in contact with the first shaft, a friction torque can be secured. The elastic member is disposed on the radially outer side of the second shaft member, and the second shaft member is disposed on the outer side with respect to the inner first shaft member.

  In the structure according to claim 1, since the elastic member is disposed radially outside the second shaft member outside the first shaft member, the elastic member is disposed between the inner first shaft member and the friction member. The tangential force is smaller than the tangential force due to the friction torque. Accordingly, since the force with which the elastic member is twisted by the torque from the friction member is greatly reduced, the elastic member acts so that the shaft end portion of the first shaft member contacts the case reliably. Accordingly, the first shaft member can be prevented from slipping and finely rotating forward and backward, and the second shaft member screwed to the first shaft member performs a stable forward / backward movement.

  Invention of Claim 2 is the tensioner of Claim 1, Comprising: The said elastic member is contacting the friction member with a contact diameter larger than the contact diameter of a said 1st shaft member and a friction member. It is characterized by.

  The invention according to claim 3 is the tensioner according to claim 1 or 2, wherein the contact surface between the friction member and the first shaft member is inclined so as to intersect the axial direction of the first shaft member. It is characterized by.

  According to the present invention, since the elastic member that biases the friction member in the contact direction with the first shaft member is provided on the radially outer side of the second shaft member, the force for twisting the elastic member is reduced. For this reason, the elastic member effectively applies an urging force in which the shaft end portion of the first shaft member contacts the case. For this reason, the rotational behavior of the first shaft member is stabilized, and the second shaft member screwed into the first shaft member is advanced and retracted stably.

  Hereinafter, the present invention will be described in detail based on illustrated embodiments. In each embodiment, the same member is assigned the same reference numeral.

  1 to 6 show a tensioner A1 according to a first embodiment of the present invention. The tensioner A1 includes a case 2, a first shaft member 3, a second shaft member 4, a biasing spring 5, a friction member 6, and an elastic member 7.

  The case 2 is formed by a body portion 2a and a flange portion 2b. The flange portion 2b extends in a direction orthogonal to the axial direction, and the body portion 2a extends in the axial direction from one side of the flange portion 2b. A housing hole 2c is formed in the body portion 2a. The front end portion of the storage hole 2c is open, and the assembly of the first and second shaft members 3, 4, the biasing spring 5, the friction member 6, and the elastic member 7 is stored from this open portion.

  The flange portion 2b of the case 2 is for mounting the engine body, and is formed with a mounting hole 2j through which a bolt (not shown) screwed into the engine body passes. By attaching the flange portion 2b to the engine body, the entire body portion 2a extending from the flange portion 2b is inserted into the engine body. As shown in FIG.1 and FIG.3, the window part 2a along the length direction of the trunk | drum 2a is formed in the trunk | drum 2a in the multiple places on the periphery. By forming the window slit 2d, the lubricating oil in the engine body can be introduced into the case 2, so that seizure during operation can be prevented.

  The 1st shaft member 3 and the 2nd shaft member 4 are arrange | positioned so that it may become the position which overlapped in radial direction, the 1st shaft member 3 is located inside, and the 2nd shaft member 4 Is located on the outside. The first shaft member 3 is rotated by being urged by the urging spring 6, and the second shaft member 4 is propelled from the case 2 by the rotation of the first shaft member 3.

  As shown in FIGS. 2 and 4, the first shaft member 3 is configured by integrally forming a shaft portion 3a on the flange portion 2b side and a screw shaft portion 3b extending in the axial direction from the shaft portion 3a. A male screw (screw portion) 8 is formed on the outer periphery of the screw shaft portion 3b. The male screw 8 is formed over substantially the entire length of the screw shaft portion 3b. A slit 3e into which the tip of a winding jig (not shown) for rotating the first shaft member 3 is inserted is formed at the shaft end of the shaft portion 3a. The slit 3e communicates with the jig hole 2e penetrating the flange portion 2b of the case 2. The tip of the winding jig is inserted into the slit 3e from the jig hole 2e, and the first hole is inserted through the slit 3e. By rotating the shaft member 3, the urging spring 5 can be wound up. After the urging spring 5 is tightened, the jig hole 2e is sealed by screwing a seal bolt (not shown).

  The rotation of the first shaft member 3 is supported by inserting the shaft end portion (the lower end portion in FIGS. 1 and 4) of the shaft portion 3 a into a receiving seat 9 provided in the case 2. By inserting into the receiving seat 9, the base end surface of the shaft end portion of the shaft portion 3 a comes into contact with the end surface of the receiving seat 9. When the shaft end portion of the shaft portion 3a comes into contact with the receiving seat 9, friction torque is generated between the first shaft member 3 and the receiving seat 9 (that is, the case 2), and the friction torque is generated in the state where the friction torque is generated. 1 shaft member 3 rotates. In addition, it is good also as a structure which makes the axial edge part of the shaft part 3a contact the inner surface of the case 2 directly, without providing the receiving seat 9 in the case 2. FIG.

  Between the shaft portion 3a and the screw shaft portion 3b, a continuous portion 3d is provided in a constricted state. The continuous portion 3d has a smaller diameter than the diameter of the shaft portion 3a, whereby a contact surface 3f positioned outside the continuous portion 3d is formed on the shaft portion 3a. As will be described later, the contact surface 3f contacts the friction member 6.

  As shown in FIGS. 2 and 5, the second shaft member 4 is formed in a cylindrical shape, and a female screw (screw portion) into which the male screw 8 of the first shaft member 3 is screwed onto the inner surface on the proximal end side. ) 10 is formed. In the second shaft member 4, the outer periphery of the portion where the female screw 10 is formed is circular, and the outer periphery of the other portion excluding this circular portion is non-circular by being subjected to parallel cutting. ing. In FIG. 5, 4a is a circular part and 4b is a non-circular part. A cap 11 is attached to the tip of the second shaft member 4 and is prevented from coming off by press-fitting a spring pin 12.

  As shown in FIG. 2, a guide 13 is attached to the distal end portion of the case 2 and is fixed by a circlip 14. The guide 13 has a sliding hole 13a, and the non-circular portion 4b of the second shaft member 4 passes through the sliding hole 13a so as to be slidable. The inner surface of the sliding hole 13 a is formed in the same non-circular shape as the non-circular portion of the second shaft member 4. Therefore, the guide 13 allows the second shaft member 4 to move in the axial direction, but acts to restrain the rotation of the second shaft member 4. The sliding hole 13a of the guide 13 and the non-circular portion 4b of the second shaft member 4 penetrating the sliding hole 13a may be non-circular such as a D-cut shape, a substantially oval shape, or a polygonal shape.

  In this embodiment, a mainspring spring is used as the biasing spring 5. The biasing spring 5 made of a mainspring spring is provided outside the shaft portion 3 a of the first shaft member 3. As shown in FIG. 3, the urging spring 5 has a hook portion 5a on one end side inserted and locked in a window slit 2d formed in the case 2, while the hook portion on the other end side is shown in FIG. 5b is inserted into the slit 3e of the shaft portion 3a and locked. As a result, the urging spring 5 rotates and urges the first shaft member 3 in one direction by tightening the urging spring 5 and applying torque. The rotation of the rotationally biased first shaft member 3 is transmitted to the second shaft member 4 by the threaded screw portions 8 and 10, but the second shaft member 4 is rotationally restrained by the guide 13. Therefore, the second shaft member 4 advances and retreats with respect to the case 2.

  As shown in FIG. 2, the friction member 6 is extrapolated to the continuous portion 3 d of the first shaft member 3. As shown in FIG. 4, the friction member 6 is formed in a circular plate shape, and a hole portion 6 a having a diameter slightly larger than that of the screw shaft portion 3 b of the first shaft member 3 is formed in the center portion thereof. Yes. Thereby, the friction member 6 is provided so as to be free to rotate with respect to the first shaft member 3. By attaching to the first shaft member 3, the friction member 6 comes into contact with the contact surface 3 f of the first shaft member 3, and friction torque is generated between the friction member 6 and the first shaft member 3 by this contact. To do.

  As the elastic member 7, a compression spring wound in a coil shape is used. The elastic member 7 made of a compression spring is disposed between both ends of the elastic member 7 so as to abut against the friction member 6 and the guide 13. The elastic member 7 is disposed between the friction member 6 and the guide 13 in a state compressed (bent) to some extent, and biases the friction member 6 so as to contact the contact surface 3f of the first shaft member 3. ing . Further, by urging the friction member 6 so as to come into contact with the first shaft member 3, the elastic member 7 is received by the shaft end portion of the shaft portion 3 a of the first shaft member 3 via the friction member 6. It is biased to come into contact with the seat 9.

  The elastic member 7 is provided on the radially outer side of the second shaft member 4. In this embodiment, a spacer 16 is extrapolated on the radially outer side of the second shaft member 4. The spacer 16 has a cylindrical shape such as a cylinder, and the base end portion comes into contact with the friction member 6 so that the first and second shaft members 3 and 4 in a screwed state do not come out of the case 2. ing. The elastic member 7 is located on the outer side of the spacer 16 so as to be positioned on the outer side in the radial direction of the second shaft member 4.

  In this embodiment, as shown in FIG. 2, an end turn is formed at the end of the elastic member 7 on the friction member 6 side, and the end face of that portion is polished. By forming the end winding in this way, the elastic member 7 can be sat down and a stable force can be applied to the friction member 6. In addition, by polishing the end face, the elastic member 7 can be sat down and a stable force can be applied, and the contact height to the friction member 6 can be reduced, and the size can be reduced. In the present invention, the present invention is not limited to this, and the end winding need not be formed at the end, and the end face need not be polished. The presence / absence of end winding and the presence / absence of end face polishing can be similarly applied to other embodiments described later.

  Next, the operation of this embodiment will be described. The first shaft member 3 contacts the receiving seat 9 with a contact radius r1, and the elastic member 7 contacts the friction member 6 with a contact radius r2. Here, since the elastic member 7 is provided on the outer side in the radial direction of the second shaft member 4 outside the first shaft member 3, the relationship r1 <r2 is established. The elastic member 7 is bent and arranged to press the friction member 6 and the first shaft member 3 in close contact with the case 2 by the axial load W. In this state, when receiving vibration from the engine, the first shaft member 3 reciprocally rotates. The friction torque T <b> 1 acts between the first shaft member 3 and the friction member 6 by the reciprocating rotational movement of the first shaft member 3. Here, T1 = W · r1 · μ, and μ is a friction coefficient between the friction member 6 and the first shaft member 3.

  Although the friction member 6 is free to rotate with respect to the first shaft member 3, since the friction torque T1 is generated between the friction member 6 and the first shaft member 3, the friction member 6 is the first shaft member. 3, and a torque in a twisting direction acts on the elastic member 7. In this case, a tangential force P1 (P1 = T1 / r1) based on the friction torque T1 is generated on the contact surface between the shaft end portion of the first shaft member 3 and the seat 9, and the elastic member 7 and the friction member 7 are in friction. A tangential force P2 (P2 = T1 / r2) is generated between the members 6. The relationship between the tangential forces P1 and P2 is P1> P2 because r1 <r2. Since the tangential force is a shear stress and P1> P2, the torque for twisting the elastic member 7 is greatly reduced. In addition to this, the surface on which the first shaft member 3 slides (the shaft end surface of the first shaft member 3) is limited to the contact radius r1, so that the first shaft member 3 can rotate and rotate. The forward and reverse rotation is prevented without stopping. Therefore, the second shaft member 4 screwed into the first shaft member 3 can move forward and backward with a stable amplitude, and a tensioner that ensures a stable behavior can be obtained.

  Further, in this embodiment, by disposing the elastic member 7 outside the spacer 16, the first shaft member 3, the second shaft member 4, the spacer 16, and the elastic member 7 can be disposed along the radial direction. Therefore, the tensioner A1 can be shortened in the axial direction, and the tensioner can be shortened.

  FIGS. 7-9 shows tensioner A2 of 2nd Embodiment of this invention. In the tensioner A2, a head portion 16a is formed on a cylindrical spacer 16. The head portion 16 a is formed at the tip end portion (upper portion) of the spacer 16 in the axial direction, and receives one end side of the elastic member 7 at the outer peripheral portion thereof. An outer peripheral portion on the guide 13 side in the head portion 16a is a tapered surface 16b that is inclined toward the base end side. The tapered surface 16b contacts the bent portion of the guide 13. Since the spacer 16 is aligned by the torque from the elastic member 7 acting on the spacer 16, the elastic member 7 can be arranged without being unevenly distributed in the radial direction.

  The friction member 6 receives the other end side of the elastic member 7 by contacting the other end side of the elastic member 7. As shown in FIG. 9, the friction member 6 has an outer peripheral portion formed in a two-step shape and a central hole 6a formed in a two-step shape. The outer peripheral portion having a two-stage shape is inserted into the other end side of the elastic member 7 and is in contact with the elastic member 7, and the elastic member 7 contacts the friction member 6 with the first shaft member 3 by this contact. Energized in the direction. By inserting the outer peripheral portion of the friction member 6 having the two-stage shape into the elastic member 7 as described above, the elastic member 7 can be stably seated, so that the elastic member 7 can be prevented from being inclined.

  The shoulder portion of the shaft portion 3a of the first shaft member 3 is in contact with the hole portion 6a of the friction member 6 having a two-stage shape. By this contact, a friction torque is generated between the friction member 6 and the first shaft member 3. By inserting the shoulder portion of the shaft portion 3a into the hole portion 6a having the two-step shape as described above, the displacement of the friction member 6 and the first shaft member 3 can be prevented, and a stable friction force can be obtained. be able to. Other structures are the same as those of the first embodiment. This embodiment can also operate in the same manner as the first embodiment. In particular, in this embodiment, since the first shaft member 3 and the elastic member 7 are guided by forming the outer peripheral portion of the friction member 6 and the hole 6a into two stages, it is possible to prevent eccentricity and displacement. This makes it possible to further stabilize the advance / retreat of the second shaft member 4 with which the first shaft member 3 is screwed, and to further stabilize the behavior of the tensioner. In this case, the outer peripheral part of the friction member 6 or the hole 6a may have a two-stage structure.

  FIG. 10 shows variations of this embodiment. In the tensioner of this form, the connecting portion 3d of the first shaft member 3 is formed in two steps, and a step portion is provided between the connecting portion 3d and the shaft portion 3a. The friction member 6 is inserted with the large-diameter portion of the continuous portion 3d, and contacts the contact surface 3f on the upper surface of the shaft portion 3a in this inserted state. Also in the structure of FIG. 10, since the friction member 6 can be prevented from tilting, the elastic member 7 can be prevented from tilting. Also, the eccentricity and displacement of the friction member 6 with respect to the first shaft member 3 can be prevented, and a stable behavior can be performed.

  FIGS. 11-15 shows tensioner A3 of 3rd Embodiment of this invention. In the tensioner A3, a coiled torsion spring is used as the biasing spring 5. The torsion spring as the urging spring 5 extends along the axial direction of the first and second shaft members 3 and 4, and a hook portion 5 a on one end side is inserted into a slit 2 g formed in the case 2. The hook 5b on the other end side is inserted into the slit 3e of the first shaft member 3 and locked. Therefore, the biasing spring 5 rotates and biases the first shaft member 3 in one direction by winding the biasing spring 5 and applying torque.

  The case 2 has a shape in which the flange portion 2b extends outward from an intermediate portion of the body portion 2a, and a portion on the tip side of the flange portion 2b is inserted into the engine body. Therefore, in this embodiment, the base end portion of the body 2a of the case 2 is exposed to the outside of the engine body.

  In this embodiment, the friction member 6 has a structure that also serves as a spacer. As shown in FIG. 12, the friction member 6 is configured by integrally including a receiving portion 6d, a spacer portion 6e, and a friction portion 6f from the distal end side (upper side) to the proximal end side (lower side). The spacer 6e is formed in a cylindrical shape such as a cylinder, and the first and second shaft members 3 and 4 are inserted into the inside in a screwed state. Therefore, the friction member 6 is disposed on the radially outer side of the second shaft member 4.

  The receiving portion 6d is formed by being bent from the distal end side of the spacer portion 6e toward the radially outer side. The receiving portion 6d is located on the tip side of the biasing spring 5. An elastic member 7 made of a compression spring is disposed between the receiving portion 6d and the guide 13. The elastic member 7 is disposed between both ends of the elastic member 7 so as to be in contact with the guide 13 and the receiving portion 6 d, and urged so that the friction member 6 is in contact with the first shaft member 3. When the elastic member 7 comes into contact with the friction member 6 (receiving portion 6 d) located outside the second shaft member 4, the elastic member 7 is disposed on the radially outer side of the second shaft member 4. In FIG. 12, r2 is a contact radius with which the elastic member 7 comes into contact with the receiving portion 6d.

  The friction part 6f is connected to the base end side of the spacer part 6e. The friction portion 6 f is an inclined surface that is inclined from the base end side of the spacer portion 6 e and spreads outward, and the friction portion 6 f contacts the first shaft member 3 as shown in FIG. 11. When the friction portion 6f contacts the first shaft member 3, the friction member 6 acts so that the first and second shaft members 3 and 4 in the screwed state do not come out of the case 2, thereby The friction member 6 also functions as a spacer.

  The first shaft member 3 has a structure in which a large-diameter contact portion 3h is formed between the shaft portion 3a and the screw shaft portion 3b. The outer peripheral surface of the contact portion 3h is an inclined surface in the same oblique direction as the friction portion 6f, and the friction member 6f contacts the contact portion 3h so that the friction member 6 and the first shaft member 3 are in contact with each other. Friction torque is generated between them. Thus, the contact portion 3h and the friction portion 6f are brought into contact with each other as an inclined surface, whereby the friction torque can be increased. In FIG. 12, r1 is a contact radius when the friction part 6f contacts the contact part 3h.

  The operation in this embodiment will be described with reference to FIG. When torque W is applied from the elastic member 7 to the state in which the contact portion 3h and the friction portion 6f are in contact with each other at the inclination angle α, a drag force W ′ perpendicular to the contact surfaces of the contact portion 3h and the friction portion 6f is generated. The drag force W ′ is directly related to the friction torque T1 that urges the friction member 6 in the direction in contact with the first shaft member 3, and when the drag force W ′ is large, the friction torque T1 is also large. Since W ′ is W ′ = W / sin α, a friction torque larger than the torque W from the elastic member 7 can be applied to the first shaft member 3. In this case, as α decreases, W ′ increases. Therefore, it is possible to adjust the friction torque T1 by adjusting α.

  As shown in FIG. 14, when the friction part 6f contacts the contact part 3h in the region from the maximum contact radius r1a to the minimum contact radius r1b, the friction torque T1 generated between the friction member 6 and the first shaft member 3 is , T1 = (2/3) (μ · W · (r1a · r1a · r1a−r1b · r1b · r1b) / (r1a · r1a−r1b · r1b) sin α). In this equation, for example, when W = 30N, μ = 0.15, α = 30 °, r1a = 8 mm, and r1b = 4 mm, a friction torque T1 of 56 N · mm is generated.

  FIG. 15 shows a configuration in which the outer shape of the contact portion 3 h in the first shaft member 3 is circular, and the friction portion 6 f of the friction member 6 is brought into contact. The friction torque T1 at this time is T1 = r1 · μ · W / sin α. For example, when W = 30N, μ = 0.15, α = 30 °, and r1 = 6 mm, a friction torque T1 of 54 N · mm is generated.

  FIG. 16 shows a change in the friction torque T1 when the inclination angle α is changed in the embodiment shown in FIG. As shown in FIG. 16, the friction torque T1 increases as the inclination angle α decreases. For example, when α = 30 ° with respect to α = 90 °, the friction torque T1 is doubled.

  In the third embodiment described above, a large friction torque T1 can be generated by reducing the inclination angle α. Therefore, in the case of the same friction torque T1, the degree of freedom of design is increased by adjusting α to be small, and this makes it possible to design a compact tensioner.

  FIG. 17 shows a tensioner A4 according to a fourth embodiment of the present invention. In the tensioner A4 of this embodiment, inclined surfaces are formed at both axial ends of the shaft portion 3a of the first shaft member 3. That is, the inclined surfaces 31 and 32 inclined in the direction in which the diameter gradually decreases are formed on the distal end side (upper end side) and the proximal end side (lower end side) of the shaft portion 3a.

  The inclined surface 31 corresponds to the friction member 6, the inclined surface 32 corresponds to the receiving seat 9, and the friction member 6 is formed with a contact hole 33 inclined at the same angle as the inclined surface 31. A support surface 34 inclined at the same angle as the inclined surface 32 is formed. Therefore, when the inclined surface 31 and the contact hole 33 are in contact with each other, the friction member 6 and the first shaft member 3 are in contact with each other, and the torque of the elastic member 7 can be transmitted to the first shaft member 3. Further, when the inclined surface 32 and the support surface 34 come into contact with each other, the first shaft member 3 rotates while being supported by the receiving seat 9 (that is, the case 2). In addition, a restricting protrusion 36 is formed on the surface of the friction member 6 on the elastic member 7 side to suppress the displacement movement of the elastic member 7 in the radial direction. As a result, the elastic member 7 does not come into contact with the second shaft member 4.

  In such an embodiment, when the torque from the elastic member 7 acts, the inclined surface 31 and the contact hole 33, and the inclined surface 32 and the support surface 34 are aligned, so the inclined surface 31, the contact hole 33, and the inclined surface 32 are aligned. And the support surface 34 can be brought into close contact with each other, and no deviation occurs. Further, the friction torque based on the torque of the elastic member 7 can be increased by the angles of the inclined surfaces 31 and 32 as in the case of the tensioner of the third embodiment.

  The present invention is not limited to the above embodiment, and various modifications can be made. For example, as the elastic member 7, a spring other than a compression spring such as a disc spring can be used.

It is a front view which shows the tensioner of 1st Embodiment of this invention. It is the X1-X1 sectional view taken on the line in FIG. FIG. 3 is a sectional view taken along line X2-X2 in FIG. (A) And (b) is the front view and bottom view which show the 1st shaft member used for 1st Embodiment. (A), (b), (c) is a top view which shows the 2nd shaft member used for 1st Embodiment, a X3-X3 sectional view, and a left view. (A) And (b) is the top view and X4-X4 sectional view taken on the line of the friction member used for 1st Embodiment. It is sectional drawing which shows the tensioner of 2nd Embodiment of this invention. It is the X5-X5 sectional view taken on the line in FIG. (A), (b), (c) is the top view which shows the friction member used for 1st Embodiment, a X6-X6 sectional view, and a bottom view. It is a fragmentary sectional view showing a modification of a 2nd embodiment. It is sectional drawing which shows the tensioner of 3rd Embodiment of this invention. It is sectional drawing of the friction member used for 3rd Embodiment. It is a fragmentary sectional view explaining an operation of a 3rd embodiment. It is a fragmentary sectional view explaining the friction torque of a 3rd embodiment. It is a fragmentary sectional view showing a modification of a 3rd embodiment. It is a graph which shows the characteristic of the friction torque of the form of FIG. It is sectional drawing which shows 4th Embodiment of this invention. It is a partially broken front view which shows the state which mounted | wore the engine main body with the tensioner. It is a top view which shows the conventional tensioner. It is the QQ sectional view taken on the line in FIG.

Explanation of symbols

A1, A2, A3, A4 Tensioner 2 Case 3 First shaft member 4 Second shaft member 5 Biasing spring 6 Friction member 7 Elastic member 8 Male screw 9 Seat 10 Female screw

Claims (3)

An inner first shaft member and an outer second shaft member that are screwed together by the threaded portion, and a biasing spring that biases the first shaft member in one direction are accommodated in the case. A tensioner that constrains the rotation of the shaft member and converts the rotational biasing force of the biasing spring into the propulsive force of the second shaft member,
The first shaft member rotates with a shaft end part in direct or indirect contact with the case, and a friction member that generates a friction torque with the first shaft member contacts the first shaft member. The elastic member is provided on the radially outer side of the second shaft member, and the elastic member urges the friction member in a direction in contact with the first shaft member. Features a tensioner.   2. The tensioner according to claim 1, wherein the elastic member is in contact with the friction member with a contact diameter larger than a contact diameter between the first shaft member and the friction member.   The tensioner according to claim 1 or 2, wherein a contact surface between the friction member and the first shaft member is inclined so as to intersect with an axial direction of the first shaft member.

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