JP5612404B2 - Cam mechanism and torque tool - Google Patents

Description

  The present invention uses a cam mechanism that acts as a torque limiter, and when tightening a tightening member such as a bolt or a nut using this cam mechanism, when the set torque value is reached, the torque limiter is actuated to tighten at the set torque value. The present invention relates to a torque tool such as a torque wrench that can be used.

  2. Description of the Related Art Conventionally, a torque wrench with a torque limiter using a cam mechanism is known, and a configuration in which a cylindrical head portion is attached to the tip of a cylindrical lever member is known. A transmission shaft having an angular shaft portion on which an engaging portion such as a hexagon socket that engages with a tightening member such as a bolt or a nut is detachably mounted on the head portion can be rotated in one direction via a ratchet mechanism. Is attached. When a tightening force is applied to the lever member by hand, and the tightening torque reaches a set torque, a torque limiter disposed between the head portion and the tip end portion of the lever member is operated, and the tightening is performed. The tightening force transmitted to the member is released (Patent Document 1).

  As a configuration of this torque limiter, a cylindrical cam shaft which is a cam member in which a plurality of cam portions are continuously provided on the outer peripheral surface in a circumferential direction is rotatably arranged in a cylindrical head body. A cylindrical roller member, which is a cam follower, is pressed against the cam surface of the cam shaft through a thrust pad attached to the tip of a torque value adjusting spring disposed in the lever member. The roller member is movable in the axial direction of the lever member and abuts on the inner peripheral surface side of the lever member. A plurality of ratchet teeth are formed in a circumferential direction on the inner peripheral surface of the shaft hole of the cam shaft, and the main shaft portion of the transmission shaft is rotatably disposed in the shaft hole. The attached ratchet pawl is engaged with the ratchet teeth. When rotation in the tightening direction is applied to the cam shaft, the ratchet pawl engages with the ratchet teeth, and the transmission shaft rotates to tighten a tightening member such as a bolt.

  The cam portion of the cam shaft constituting the torque limiter has a configuration in which a torque transmitting cam surface having a steep slope and a torque non-transmitting cam surface having a gentle gentle slope are formed on both sides of the cam top. The roller member waits in a state of being pressed against the torque transmission cam surface of the cam portion, and when the tightening force is transmitted to the roller member via the lever member, the cam shaft is interposed via the torque transmission cam surface. Rotate in the tightening direction. As the tightening force on the tightening member such as a bolt increases, the reaction force against the roller member from the torque transmission cam surface increases, and the roller member moves toward the cam top against the spring force of the torque value adjusting spring. Moving. Then, when the roller member gets over the cam top, the force for rotating the cam shaft in the tightening direction by the roller member is not applied, and the user is notified that the set torque value has been reached.

UK Patent Application No. 2148767A

  By the way, in the torque limiter using the conventional cam mechanism, the spring force of the torque value adjusting spring for determining the set torque value directly acts on the roller member. The spring force of the torque value adjusting spring increases in proportion to the magnitude of the set torque value. Therefore, during the tightening operation, the roller member receives a reaction force from the torque transmission cam surface and the spring force of the torque value adjusting spring. It moves while being guided by the inner peripheral wall surface of the lever member.

  Since the spring force of the torque value adjusting spring determines the set torque value, a very large pressure of several tens N to several thousand N is applied to the cam surface which is the roller contact surface of the roller member and the cam portion.

  At the time of shipment from the factory, a lubricant such as grease is applied to the surface of the cam portion. However, since the roller member rolls in contact with the cam surface due to a large applied pressure, it is applied to the surface of the cam surface. The lubricant that is being pushed out is gradually pushed out and protrudes on both sides of the cam surface and the roller member in the thickness direction. The cam member and the roller member are both made of ferrous metal and polished on the surface, so the ability to hold the lubricant on the surface is low, the lubricant coating layer applied on the surface is lost, and the oil runs out. This condition occurs early.

  It is unclear how many times the torque limiter runs out of oil, but if it occurs earlier than the predetermined lubricant replenishment time, the user tightens without noticing this. When working, the cam surface and roller member are in direct metal contact, the surface of the soft material becomes rough, and smooth tightening work cannot be performed, and tightening with the set torque value is ensured. There is a risk that it will not be possible.

  A first object of the present invention is to provide a cam mechanism that functions as a torque limiter that can prevent premature oil shortage.

  A second object of the present invention is a torque tool such as a torque wrench that uses a cam mechanism as a torque limiter, which can maintain a lubricant coating layer on the contact surface between the cam member and the roller member for a long period of time, and can be tightened smoothly. It is an object of the present invention to provide a torque tool capable of performing reliable tightening with work and a set torque value.

A cam mechanism that achieves the first object of the present invention is connected between an input unit and an output unit, and a driving force generated by relative rotation between the input unit and the output unit exceeds a predetermined torque value. A cam mechanism that acts as a torque limiter that cuts off power transmission, and is connected to the output unit and has a cam member formed on the outer periphery thereof, and is held by the input unit, with the rotation of the input unit. in a cam mechanism having a roller member that moves while contact with the cam surface of the cam portion Te, and a resilient member for setting a torque limit value by pressure contact with the roller member relative to the cam surface, the cam The surface includes a torque transmitting cam surface that applies a reaction force to the roller member against the elastic force of the elastic member, and a torque non-transmitting cam that is applied with pressure by the roller member due to the elastic force of the elastic member. Face and And, said cam surface, characterized in that the formation of the oil retention part lubricant applied to the cam surface is accumulated.

A torque tool that achieves the second object of the present invention is connected between an input unit and an output unit, and a driving force generated by relative rotation between the input unit and the output unit exceeds a predetermined torque value. A cam mechanism that acts as a torque limiter that cuts off power transmission, and is connected to the output unit and has a cam member formed on the outer periphery thereof, and is held by the input unit, with the rotation of the input unit. A cam mechanism having a roller member that moves while being in contact with the cam surface of the cam portion, and an elastic member that sets a torque limit value by pressing the roller member against the cam surface. A torque tool having , on a surface thereof, a cam mechanism in which an oil sump for storing lubricant applied to the cam surface is formed, or a cam mechanism according to claim 1 , wherein the cam member is interposed via a one-way rotation mechanism. Connected A torque transmission shaft which constitutes the output unit to tighten the fastener,
A fastening force applying part that applies a fastening force to the input part, and the fastening part is fastened until the cam mechanism cuts off the power by rotating the input part by the fastening force applying part. And

  In the torque tool having the above-described configuration, as the input portion, the cam member is rotatably disposed, and the torque transmission shaft is coaxially disposed in the cam member via the one-way rotation mechanism; A cylindrical lever fixed to a rear end portion of the head portion that houses therein a spring force transmission rod urged by a torque value setting spring, which is the elastic member, as the tightening force applying portion, and the head A roller support that is rotatably attached to the part via a support shaft and supports the roller member rotatably, and a spring force acting on the spring force transmission rod acts to generate a tightening reaction force on the roller member. And a lever body.

  In the torque tool having the above-described configuration, as the input portion, the cam member is rotatably disposed, and the torque transmission shaft is coaxially disposed in the cam member via the one-way rotation mechanism; A cylindrical lever fixed to a rear end portion of the head portion that houses therein a support member that is urged by a torque value setting spring that is the elastic member, as the tightening force applying portion; The roller member is supported at the tip of the support member.

  According to the cam mechanism of the present invention, even if a large force is applied to the cam surface by the roller member as a torque limiter, the lubricant such as grease stored in the oil reservoir portion is passed through the roller member even if the lubricant layer becomes thin. Since it is reapplied, early oil shortage can be prevented.

  According to the torque tool of the present invention, in a configuration in which a cam mechanism is used as a torque limiter, early oil shortage on the cam surface can be prevented, so that a smooth tightening operation can be maintained over a long period of time.

Sectional drawing which shows the whole structure of the torque wrench which concerns on Embodiment 1 of this invention. The enlarged view of the head part in FIG. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. FIG. 4 is an external perspective view of the head portion of FIGS. 1 to 3. FIG. 5 is a vector diagram of a tightening force acting on the torque limiter of FIG. 4. The front view which shows the other example of a sump part. The front view which shows the other example of a sump part. The front view which shows the other example of a sump part. The front view which shows the other example of a sump part. FIG. 6 is a top external view of a torque wrench according to a second embodiment. The front external view of the torque wrench of FIG. FIG. 11 is a cross-sectional view of FIG. 10. The longitudinal cross-sectional view of FIG.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

Embodiment 1
1 is a cross-sectional view showing an overall configuration of a torque wrench according to Embodiment 1 of the present invention, FIG. 2 is a view showing a head portion in FIG. 1, FIG. 3 is a cross-sectional view taken along line AA in FIG. It is an external appearance perspective view of the torque limiter using the cam mechanism shown in FIGS.

  The torque wrench 1 of this embodiment is a torque tool provided with a mechanical torque limiter using a cam mechanism that can be tightened with a torque set with tightening members such as bolts and nuts.

  The torque wrench 1 includes a head portion 2 that is an input portion that engages with a tightening member (which will be described below using a bolt as an example), and a cylindrical shape that is a tightening force applying portion that applies a tightening force to the input portion. A lever member (lever) 4 is provided, and a grip 6 is attached to the rear end side of the lever 4 to be gripped by a user when tightening. The head portion 2 is integrally formed with a screw cylinder portion 3b having a screw portion on an inner peripheral surface at a rear end portion of a substantially rectangular parallelepiped case portion 3a having a curved front end portion. The case portion 3a of the head portion 2 and the lever 4 are coupled by screwing the formed screw portion into the screw cylinder portion 3b, and the lever 4 and the case portion 3a communicate with each other.

  When the axial direction of the lever 4 is the x axis, the vertical direction of the case portion 3a is the z axis, and the direction perpendicular to the x axis and the z axis is the y axis, the case portion 3a of the head portion 2 has one end in the z axis direction. It is open and closed by the lid 3c. In the case portion 3a, a cam shaft 8 which is a cam member having a shaft hole 8a formed in the central portion on the distal end side is disposed.

  The cam shaft 8 in which the shaft hole 8a is formed has an upper peripheral groove 8b and a lower peripheral groove 8c formed of curved concave portions at both ends of a shaft portion extending in the z-axis direction. A plurality (six in this embodiment) of cam portions 7 are formed at equal intervals along the circumferential direction between 8b and the lower circumferential groove 8c. A circular recess 3e having the same axis as the cam shaft 8 is formed on the upper wall 3d of the case 3a. An upper peripheral groove 8b formed on the inner peripheral wall surface of the recess 3e and the upper end of the cam shaft 8 is formed. A plurality of steel balls 9a are arranged with no gap between them and constitute a radial bearing. The steel ball 9a also contacts the upper inner wall surface of the recess 3e and functions as a thrust bearing. In addition, a shallow recess 3f that forms a gap with the upper end of the camshaft 8 is formed in the recess 3e.

  The lid 3 c is formed with a circular recess 3 g having the same axis as the cam shaft 8, and is substantially between the inner peripheral wall surface of the recess 3 g and the lower peripheral groove 8 c formed at the lower end of the cam shaft 8. A plurality of steel balls 9b are arranged without gaps to constitute a radial bearing. The steel ball 9b also contacts the lower inner wall surface of the recess 3g and functions as a thrust bearing. In addition, a shallow recess 3h that forms a gap with the lower end of the camshaft 8 is formed in the recess 3g. As shown in FIG. 3, the diameter of the steel ball 9a and the steel ball 9b can be made as close as possible to the depth of the recessed portion 3e and the recessed portion 3g, so that the upper peripheral groove 8b and the lower peripheral groove 8c are formed of the steel ball 9a. The pressure receiving area for the steel ball 9b can be increased, and the Hertz stress, which is the stress received from the steel ball 9a and the steel ball 9b, can be reduced accordingly, and the wear of the radial bearing can be reduced.

  As shown in FIG. 4, ratchet teeth 8d are formed on the inner peripheral surface of the shaft hole 8a of the cam shaft 8, and the main body shaft portion 11a of the transmission shaft 11 as an output portion is inserted into the shaft hole 8a. ing. A pair of ratchet claws 10 forming a one-way rotation mechanism (one-way clutch) disposed symmetrically with respect to the central axis is urged by a ratchet spring (not shown) to engage with the ratchet teeth 8d on the main body shaft portion 11a of the transmission shaft 11. When the cam shaft 8 rotates in the clockwise direction, the transmission shaft 11 rotates integrally. A rectangular shaft portion 11b penetrating the lid 3c is formed at the distal end portion of the transmission shaft 11, and a socket or the like (not shown) is detachably mounted. Further, a steel ball 9c forming a thrust bearing is disposed between the end surface of the main body shaft portion 11a and the recessed portion 3f.

  The plurality of cam portions 7 formed on the outer peripheral portion of the cam shaft 8 are configured such that a torque transmitting cam surface 7a having a steep slope and a torque non-transmitting cam surface 7b having a gentle gentle slope are formed on both sides of the cam top. It is said.

  On the other hand, at the rear part of the case portion 3a, a roller support lever body 12 formed in a substantially rectangular parallelepiped shape constituting a link mechanism is swingably attached to a support shaft 16 whose axial direction is the Z-axis direction. The roller support lever body 12 has a support shaft 16 attached to one end side in the longitudinal direction, and is formed to have a thickness substantially equal to the thickness of the cam portion 7 in the Z-axis direction. A solid roller member 14 formed in a cylindrical shape that forms a cam follower is rotatably held on the roller support lever body 12 in a bearing recess 12 a formed in a concave shape on the side facing the cam portion 7. . An inner diameter portion of the bearing recess 12a is formed on an inner diameter surface that is substantially the same diameter as the outer diameter of the roller member 14, and the roller member 14 contacts the cam surface of the cam portion 7 while rotating.

  The roller support lever body 12 is formed with a pivot recess 12b so as to face the shaft hole of the screw cylinder portion 3b. The pivot recess 12b is formed at a position longer than the length up to the center position of the roller member 14, starting from the support shaft 16 in the longitudinal direction of the roller support lever body 12.

  In the lever 4, a torque value setting spring 22 is disposed between the rod seat 20 and the adjusting nut 21 on the rear end side. When the torque value adjusting screw rod 24 that is screwed into the adjusting nut 21 is rotated from the rear end of the lever 4, the adjusting nut 21 is screwed back and forth along the axial direction, and the spring pressure applied to the rod seat 20 is increased. adjust.

  The rod sheet 20 is formed with a pivot recess 20a facing the pivot recess 12b of the roller support lever body 12, and the spring force is transmitted between the pivot recess 20a of the rod sheet 20 and the pivot recess 12b of the roller support lever body 12. A rod 18 is arranged. Both ends 18a and 18b of the spring force transmission rod 18 are formed as spherical surfaces (hereinafter referred to as spherical ends), and even if the positions of the pivot recess 12b and the pivot recess 20a in the x-axis direction are shifted in the y-axis direction and the z-axis direction. In response to this shift, the pivot recess 12b abuts on the pivot recess 20a.

  In a non-tightened state where the torque wrench 1 is not tightening a bolt, the roller member 14 is moved from the spring force transmission rod 18 to the base portion of the torque transmission cam surface 7a of the cam portion 7 by the spring force of the torque value setting spring 22. The roller member 14 is pressed against the support lever 12 at this position, and the roller member 14 is held stationary and stably held on the cam portion 7. In this stationary state, the spring force transmission rod 18 is in a posture parallel to the x-axis. . In addition, bearing concave portions 26 into which steel balls 25 are fitted are formed on both upper and lower surfaces of the roller support lever body 12, and the upper and lower steel balls 25 are in contact with the inner surfaces of the case portion 3a and the lid 3c to support the roller. The lever body 12 is positioned in the z-axis direction, and the roller support lever body 12 can be smoothly rotated with the support shaft 16 as a fulcrum.

  When bolt tightening is started from the non-tightened state where the roller support lever body 12 is held stationary, the tightening force applied to the lever 4 is transmitted from the support shaft 16 to the roller support lever body 12 and is cammed by the roller member 14. Applied to the torque transmission cam surface 7a of the portion 7. As the bolt tightening progresses, the roller member 14 receives a reaction force from the torque transmission cam surface 7 a, so that the roller support lever body 12 receives a turning force in the counterclockwise direction around the support shaft 16. At this time, the roller support lever body 12 moves the spring force transmission rod 18 toward the rear end side of the lever 4 against the urging force of the torque value setting spring 22 according to the principle of lever. That is, the operation of the torque limiter is started.

  As the tightening force for the bolt increases, the reaction force from the torque transmission cam surface 7a to the roller member 14 increases, and the roller member 14 moves to the cam top side against the spring force of the torque value adjusting spring 22. When the roller member 14 gets over the cam top of the cam portion 7, the torque limiter is activated so that the force for rotating the cam shaft 8 in the tightening direction by the roller member 14 is not activated, and the set torque value is reached. Inform the user.

  In addition, when the roller member 14 is in the operating state of the torque limiter, which is in a state of reaching the cam top position, the roller member 14 shifts to contact with the torque non-transmitting cam surface 7b. The spring force of the torque value adjusting spring 22 is applied via the spring force transmission rod 18 to act clockwise, and the tightening force applied to the lever 4 is abruptly reduced to support the roller. The lever 4 idles with respect to the bolt until the lever body 12 is in the stationary state described above.

  Here, with reference to FIG. 5, the relationship between the forces acting on each member constituting the torque limiter of the torque wrench of the present embodiment will be described.

  In the non-tightened state of the torque wrench 1, the roller support lever body 12 is in the stationary state described above, and the reaction force acting on the roller member 14 from the torque transmission cam surface 7a is P1. The reaction force P <b> 1 is a normal force at the contact position between the torque transmission cam surface 7 a and the roller member 14. In the present embodiment, the vector direction of the reaction force P1 is deviated by an angle θ from the base axis direction that is an axis connecting the center of the support shaft 16 and the axis center of the roller member 14 with respect to the direction in which the bolt is tightened.

Therefore, when a tightening force is applied from the roller member 14 to the torque transmission cam surface 7a of the cam portion 7 at the time of tightening the bolt, the cam top side extends along the tangential direction between the roller member 14 and the torque transmission cam surface 7a. The reaction force P <b> 2 directed toward the roller acts on the roller member 14, and a force that pushes the roller member 14 toward the cam top side acts. Here, reaction forces P2 and P1 are
P2 = P1 × tan θ (1)
Are in a relationship. As can be seen from the above equation (1), if the angle θ between the normal direction and the base axis direction at the contact position between the torque transmission cam surface 7a and the roller member 14 is small, the force P2 is larger than the force P1. It becomes a small force. The roller support lever body 12 is pushed to the rear side of the torque wrench 1 by the force P2 that pushes out the roller member 14, and the force acts on the spring force transmission rod 18 via the pivot recess 12b.

  On the other hand, the force F acting on the spring force transmission rod 18 by the roller support lever body 12 can be made smaller than the force P2 by which the torque transmission cam surface 7a pushes the roller member 14.

  This is because the inter-axis distance r2 between the axis of the support shaft 16 and the center of one spherical end 18a of the spring force transmission rod 18 is the distance between the axis of the support shaft 16 and the axis of the roller member 14. This is because it is larger than r1. That is, the moment (torque) around the support shaft 16 is defined by the product of the distance from the support shaft 16 to the force application point and the acting force, and the moment (torque) around the support shaft 16 in the roller member 14 and the spring The moment (torque) around the support shaft 16 at one of the spherical end portions 18a of the force transmission rod 18 becomes equal. Therefore, the force F acting on the position r2 larger than the distance r1 from the support shaft 16 becomes smaller than P2.

  The fact that the force F acting on the spring force transmission rod 18 is smaller than the force P1 means that the force for pushing back the spring 22 is smaller than P1. Then, in order to press the roller 14 against the cam 8, the force with which the torque value setting spring 22 presses the link portion 12 is also smaller than P1.

  For this reason, in the torque wrench 1 of this embodiment, as the torque value setting spring 22, a spring having a smaller spring constant than that of the conventional one can be used. Further, since the force acting on the spring force transmission rod 18 from the roller support lever body 12 and the force acting on the rod seat 20 from the spring force transmission rod 18 are also smaller than P1, the spring force transmission rod 18 and the rod For the sheet 20 and the like, a small and lightweight member can be used. Therefore, according to the torque wrench 1 of this embodiment, the effect that the torque wrench 1 as a whole can be reduced in size and weight can be obtained.

  As described above, by changing the angle θ between the direction (normal direction) of the force P1 at the contact position between the torque transmission cam surface 7a of the cam portion 7 and the roller member 14 and the baseline axis direction, the force P2 and Although the magnitude of F can be changed, θ is preferably larger than 0 degree and smaller than 45 degrees.

  If the angle θ is 0 degree, the normal direction force P1 and the link direction coincide with each other, so that the roller 14 is simply pushed in the direction of the link pin 16, and the roller 14 is spring-loaded against the roller 14. The component force in the direction of pushing back against the force 22 does not act at all. Therefore, when it is 0 degree, the function as a torque wrench is not fulfilled, which is not preferable.

  In addition, when the angle is smaller than 0 degrees, that is, in FIG. 5, the direction of the force P1 is on the counterclockwise direction side with respect to the base axis position connecting the support shaft 16 and the roller member 14, the roller member 14 The acting force acts in a direction opposite to the direction in which the roller member 14 is pushed back against the spring force of the torque value setting spring 22. Accordingly, in this case as well, the function as the torque wrench 1 is not achieved, which is not preferable.

  When θ is 45 degrees or more, the normal direction forces P1 and P2 become the same magnitude, and the force applied to the torque value adjustment spring 22 by the function of the roller support lever body 12 is as follows. Since the effect of making it small becomes low, it is not preferable.

  The adjustment of the angle θ between the base axis direction and the direction of the force P1 (normal direction) may be performed by changing the base axis direction by changing the positional relationship between the support shaft 16 and the roller member 14. The curved shape of the torque transmission cam surface 7a of the cam portion 7 may be changed and adjusted. For example, if the support shaft 16 is disposed closer to the distal end side of the head portion 2 than the position shown in FIG. 5, θ increases and P2 increases accordingly. Further, by increasing the inclination of the inclined surface of the torque transmission cam surface 7a that comes into contact with the roller member 14 in the non-tightened state, the normal direction is close to the baseline axis direction, so that θ can be reduced. If the inclination is reduced, θ can be increased.

  Further, in the torque wrench 1 of the present embodiment, the torque value can be similarly changed by changing the distance r2 between the support shaft 16 and the pivot recess 12b (that is, the position at which one spherical end 18a of the rod 18 is engaged). The force acting on the setting spring 22 can be changed. For example, when the pivot recess 12b is set at a position far from the support shaft 16 so that the inter-axis distance r2 is longer than the state shown in FIG. 5, the moment around the support shaft 16 is the same as described above. Therefore, F can be reduced. However, when the inter-axis distance r2 is increased, the roller support lever body 12 is naturally increased in size and the head portion 2 is increased in size.

  Further, when the inter-axis distance r2 is increased, the deviation (in the y-axis direction) between the position of the pivot recess 12b and the position of the pivot recess 20a of the rod seat 20 increases in the non-tightened state. If it does so, the inclination with respect to the x-axis direction of the torque wrench 1 of the spring force transmission rod 18 in a non-tightening state will become large. When a force acts on the rod 18 in this state, the y-axis direction component of the force acting on the rod sheet 20 increases. As a result, the rod sheet 20 is pressed against the inner surface of the lever 4 by the force in the y-axis direction component and the friction increases, which is not preferable because it causes a decrease in torque measurement accuracy.

  As described above, according to the torque wrench 1 of the present embodiment, as a torque limiter configuration, the solid cylindrical roller member 14 that contacts the cam portion 7 of the cam shaft 8 is replaced with the bearing recess 12a of the roller support lever body 12. The force acting against the force of the torque value adjusting spring 22 can be made smaller than the force in the normal direction acting on the roller member 14 from the torque transmission cam surface 7a. become. Thereby, members, such as the torque value adjustment spring 22, the spring force transmission rod 18 which connects the roller support lever body 12, and the torque value adjustment spring 22, can be reduced in size and weight. Therefore, a small and light torque wrench can be provided.

  In the case of a torque limiter type torque wrench configured using the conventional cam mechanism disclosed in British Patent Application No. 2148767A, in which a roller that follows the cam is directly pressed against the cam by a spring, When sliding while rotating along the torque transmission cam surface of the cam, friction occurs with the inner surface of the head or lever. However, according to the torque wrench 1 of the present embodiment, the roller member 14 is supported by the re-roller support lever body 12 so as to be swingable around the support shaft 16, so that it is between the head portion 2 and the inner surface of the lever 4. There is no friction. Therefore, it is possible to provide a torque wrench with reduced friction during operation compared to the conventional torque wrench.

  In the present embodiment, the spring force transmission rod 18, the roller support lever body 12 and the rod sheet 20 have been described as engaging structures having a spherical surface and a concave surface that enable a pivot operation, but the present invention is not limited to this. Absent. As described above, in the torque wrench 1 of the present embodiment, the operation of the roller member 14 tracing the cam surface of the cam portion 7 is an operation on the xy plane shown in FIG. Therefore, the both ends of the spring force transmission rod 18 may be engaged with and supported by the roller support lever body 12 and the rod sheet 20 through the shaft, or may slide only in the circumferential direction in the xy plane. It is good also as such a disk-shaped engaging part.

  In the present embodiment, for example, grease is applied to the cam surface of the cam shaft 8 as a lubricant over the entire circumference. An oil groove 30 as an oil reservoir for storing oil is formed on the cam surface of the cam shaft 8 in the thickness direction of the cam shaft 8. The oil groove 30 is disposed on the torque non-transmitting cam surface 7b. In this embodiment, the oil groove 30 is formed on all six torque non-transmitting cam surfaces 7b.

  Since the roller member 14 applies a large pressing force corresponding to the set torque value to the contact surface with the torque transmission cam surface 7a, the grease applied on the torque transmission cam surface 7a is scraped off. The roller member 14 is pushed out along the moving direction. The pressure applied when the roller member 14 passes the cam top and moves on the torque non-transmitting cam surface 7b gradually decreases. Therefore, when the number of tightening operations is still small, grease pushed out from the torque transmitting cam surface 7a remains on the torque non-transmitting cam surface 7b, but the grease on the torque non-transmitting cam surface 7b remains. As the number of tightening operations is increased, the grease protrudes from the cam surface of the cam shaft 8 due to its own weight, and the grease disappears from the cam surface of the cam shaft 8.

  However, in the present embodiment, the oil groove 30 is formed on the torque non-transmitting cam surface 7b, and the grease pushed out from the torque transmitting cam surface 7a to the torque non-transmitting cam surface 7b is temporarily stored in the oil groove 30. ing.

  The oil groove 30 applies the grease stored in the oil groove 30 to the roller member 14 and prevents the grease from protruding from the torque non-transmitting cam surface 7b as the number of tightening operations increases. The function of forming a lubricant layer on the torque transmission cam surface 7a is provided. Accordingly, the lubricant such as grease applied to the cam surface of the cam shaft 8 can be used without waste, and the replenishment timing (number of tightening operations) of the lubricant such as grease can be set long.

  The oil groove 30 can also be formed on the torque transmission cam surface 7a only to eliminate the oil shortage. However, the oil groove 30 forms a recess on the torque transmission cam surface 7a, and when the roller member 14 reaches the oil groove 30, the applied pressure decreases for a moment, and the misunderstanding that the set torque value has been reached. give. For this reason, the force applied to the handle member loosens momentarily, but the force applied to the handle member again increases due to the continuation of the tightening operation, and the tightening operation may be disturbed, resulting in a decrease in tightening accuracy by the torque wrench. is there.

  For this reason, in this embodiment, the oil groove 30 is formed on the non-torque transmission surface 7b. Further, the position of the oil groove 30 is provided at a position continuous with the base portion of the torque transmission cam surface 7a in a stationary state where the roller member 14 is stably held at the base portion of the torque transmission cam surface 7a. By providing the oil groove 30 at a position continuous with the base of the torque transmission cam surface 7a, the roller member 14 pushes the lubricant such as grease in the oil groove 30 to the torque transmission cam surface 7a without loss, and the roller member 14 transmits torque. A lubricant layer such as grease can be formed on the cam surface 7a.

  The oil groove 30 in the present embodiment has, for example, a U-shaped cross-sectional shape orthogonal to the axial direction of the camshaft 8, and the cam surface is connected with a curved surface, with an acute angle portion from the opening end of the oil groove 30. In order to prevent the surface of the roller member 14 from being damaged.

  In addition, as the oil sump portion, one oil groove 30 formed along the axial direction of the camshaft 8 is taken as an example. However, as shown in FIG. A configuration in which a plurality of axial grooves are formed, an oil groove 32 having a concave cross section as shown in FIG. 7 is formed obliquely with respect to the Z axis, and a circular groove 33 having a planar circular shape is formed in the Z axis direction as shown in FIG. For example, a configuration in which a plurality of rectangular grooves 34 having a planar rectangular shape extending around the Z axis are provided in the Z axis direction as shown in FIG.

Embodiment 2
10 is a top external view of the torque wrench of the second embodiment, FIG. 11 is a front external view of the torque wrench of FIG. 10, FIG. 12 is a cross-sectional view of FIG. 10, and FIG.

  In FIG. 10, the torque wrench 50 of the present embodiment has an external structure in which a cylindrical head portion 52 is fixed to the front portion of a cylindrical lever member (lever) 51, and has a cylindrical shape extending rearward from the head portion 52. The screw coupling portion 53 is screwed to a screw portion formed on the inner periphery of the front portion of the lever 51, and the head portion 52 and the lever 51 are fixed.

  A torque value setting spring 54 is provided in the lever 51. The rear end portion of the lever 51 includes a torque value adjusting screw 55 and an adjusting nut 56, and a torque adjusting mechanism that moves the adjusting nut 56 in the axial direction by rotating the torque value adjusting screw 55 is attached. The rear end of the torque value setting spring 54 is in contact with the front end of 56. A thrust member 57 is attached to the tip of the torque value setting spring 54, and the tip of the thrust member 57 is inserted into the screw coupling portion 53. A support member 60 that rotatably supports a roller member 58 facing inside the head portion 52 by a support shaft 59 is attached to the distal end portion of the thrust member 57. The support member 60 and the thrust member 57 are integrated with each other in the longitudinal direction of the lever 51. It can move along the direction (axial direction).

  A transmission shaft 61 having a rotation center axis in a direction orthogonal to the axial direction of the lever 51 is rotatably mounted in the head portion 52, and a cam shaft 62 formed in a cylindrical shape as a cam member on the outer periphery of the transmission shaft 61. Is attached rotatably with a gap. In addition, annular roller bearings 63 are respectively attached to the upper and lower sides of the cam shaft 62, and the cam shaft 62 is rotatably attached to the head portion 52 via the upper and lower roller bearings 63.

  A plurality of ratchet teeth 64 are formed along the circumferential direction on the inner peripheral surface of the cam shaft 62, and the ratchet claw urged toward the ratchet teeth 64 by the spring 65 on the outer periphery of the ratchet teeth 64 and the drive shaft 61. 66 constitutes a ratchet mechanism, and the drive shaft 61 rotates integrally with the clockwise direction of the cam shaft 62.

  Similarly to the first embodiment, a plurality of (six in this embodiment) cam portions 67 are formed on the outer peripheral portion of the cam shaft 62 at equal intervals along the circumferential direction and are urged by the pressing spring 54. 58 is pressed by the cam portion 67. As in the first embodiment, the cam portion 67 is formed with a torque transmission cam surface 67a and a torque non-transmission cam surface 67b. The oil groove 30 shown in the first embodiment, for example, is used as an oil reservoir on the torque non-transmission cam surface 67b. Is forming. Note that a lubricant such as grease is applied to the cam surface of the cam shaft 62 as in the first embodiment. Of course, the oil sump portion having the configuration shown in FIGS. 6 to 9 can also be used.

  The operator fits a socket (not shown) engaged with the drive shaft 61 into a member to be fastened (not shown) such as a bolt or a nut, grips the grip 68 of the handle 51 by hand, and rotates it clockwise. When the roller member 58 moves, the roller member 58 comes into contact with the cam portion 67 to rotate the cam shaft 62 in the clockwise direction, and the drive shaft 61 is rotated integrally with the cam shaft 62 to tighten the member to be fastened. When the tightening torque begins to rise, the cam operation of the cam portion 67 and the roller member 58 causes the roller member 58 to move rearward in the axial direction of the lever 51 against the spring force of the pressing spring 54, and the lever 51 is rotated. By detecting the decrease in force, the torque detection reaching the set torque value is detected.

  In the second embodiment, as in the first embodiment, the lubricant such as grease stored in the cam groove 30 of the torque non-transmitting cam surface 67b is pushed onto the torque transmitting cam surface 67a by the roller member 58. A lubricant such as grease that has been applied and previously applied to the cam surface can be used effectively, and surface damage to the roller member 58 due to early oil shortage can be prevented.

  In the first and second embodiments described above, a manual operation torque wrench is used as an example of the torque tool. However, the present invention is not limited to this, and a roller member, a cam member, and a torque value adjustment tool. As long as the cam mechanism having a spring is used as a torque limiter, it can be applied to any type of torque tool, and can also be applied to an automatic type such as electric drive or air drive.

  Further, although the case where the cam mechanism acting as a torque limiter is applied to a torque wrench has been described as an example, it is needless to say that the present invention is not limited to a torque wrench and can be applied to other devices.

  Although the present invention has been described in detail according to particular embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

DESCRIPTION OF SYMBOLS 1,50 Torque wrench 2,52 Head part 3a Case part 3b Screw cylinder part 3c Cover body 3d Upper wall part 3e, 3f, 3g, 3h Indentation part 4, 51 Lever member (lever)
5 Shaft hole 6, 68 Grip 7, 67 Cam part 7a, 67a Torque transmission cam surface 7b, 67b Torque non-transmission cam surface 8 Cam shaft 8a Shaft hole 8b Upper peripheral groove 8c Lower peripheral groove 8d Ratchet teeth 9a, 9b, 9c Steel Balls 10, 66 Ratchet claws 11, 61 Transmission shaft 11a Main shaft 11b Square shaft 12 Roller support lever 12a Bearing recess 12b Pivot recess 14, 58 Roller member 16 Support shaft 18 Spring force transmission rod 20 Rod seat 20a Pivot recess 21 , 56 Adjustment nut 22, 54 Torque value setting spring 24, 55 Torque value adjustment screw 25 Steel ball 26 Bearing recess 53 Screw coupling portion 57 Thrust member 59 Support shaft 60 Support member 62 Cam shaft 63 Roller bearing 64 Ratchet teeth

Claims (4)

A cam mechanism that is connected between an input unit and an output unit and acts as a torque limiter that interrupts power transmission when a driving force generated by relative rotation between the input unit and the output unit exceeds a predetermined torque value. There,
A cam member connected to the output portion and having a cam portion formed on the outer periphery;
A roller member that is held by the input unit and moves while contacting the cam surface of the cam unit as the input unit rotates;
An elastic member that sets the torque limit value by pressing the roller member against the cam surface;
In the cam mechanism having
The cam surface includes a torque transmitting cam surface that applies a reaction force to the roller member against the elastic force of the elastic member, and a torque non-transmitting force that is applied by the roller member due to the elastic force of the elastic member. Cam surface for
A cam mechanism characterized in that an oil reservoir for storing a lubricant applied to the cam surface is formed on the cam surface. A cam mechanism that is connected between an input unit and an output unit and acts as a torque limiter that interrupts power transmission when a driving force generated by relative rotation between the input unit and the output unit exceeds a predetermined torque value. A cam member connected to the output portion and having a cam portion formed on an outer periphery; and a roller that is held by the input portion and moves while contacting the cam surface of the cam portion as the input portion rotates. In a cam mechanism having a member and an elastic member that sets a torque limit value by pressing and contacting the roller member against the cam surface, oil that accumulates lubricant applied to the cam surface is stored on the cam surface A torque tool having a cam mechanism in which a pool portion is formed, or the cam mechanism according to claim 1 ,
A torque transmission shaft that constitutes the output portion for fastening a fastening body connected to the cam member via a one-way rotation mechanism;
A tightening force applying unit that applies a tightening force to the input unit;
Have
A torque tool characterized in that the input body is rotated by the tightening force applying section to tighten the fastening body until the cam mechanism cuts off the power. As the input portion, the cam member is rotatably disposed, and the torque transmission shaft is coaxially disposed in the cam member via the one-way rotation mechanism;
A cylindrical lever that is fixed to the rear end of the head portion that houses therein a spring force transmission rod that is biased by a torque value setting spring that is the elastic member, as the tightening force application portion;
The roller is rotatably attached to the head portion via a support shaft, and the roller member is rotatably supported, and a spring force via the spring force transmission rod acts to generate a tightening reaction force on the roller member. A roller support lever body;
The torque tool according to claim 2 , further comprising: As the input portion, the cam member is rotatably disposed, and the torque transmission shaft is coaxially disposed in the cam member via the one-way rotation mechanism;
A cylindrical lever fixed to a rear end portion of the head portion that houses therein a support member that is urged by a torque value setting spring that is the elastic member, as the tightening force applying portion; The torque tool according to claim 2 , wherein the roller member is supported on a tip portion of the support member.

Images