JPWO2015162659A1 - Torque limiter - Google Patents

Abstract

An object of the present invention is to provide a torque limiter capable of improving durability of an inner ring member and further reducing torque fluctuation. A coil spring is wound around an inner ring member so as to generate a frictional force with an outer surface of an inner ring member formed by press forming a metal, and an outer ring member provided outside the inner ring member. The inner circumferential surface locks the end of the coil spring 12 and supports the inner ring member 11. A linear fluorine grease having a kinematic viscosity of a predetermined value or less is applied between the outer surface of the inner ring member 11 and the coil spring 12. Lubricate the contact surface. [Selection] Figure 1

Description

  The present invention relates to a torque limiter that transmits torque less than a predetermined value and blocks transmission of torque exceeding a predetermined value.

  There is a contact type torque limiter that can obtain rotational torque by mechanical friction, and the contact type torque limiter is generally composed of four parts: an inner ring member, a coil spring, an outer ring member, and a sealing member ( Patent Document 1). A coil spring is tightly fitted on the outer periphery of the inner ring member and fixed to the outer ring member, and a predetermined rotational torque is obtained by mechanical friction between the inner ring member and the coil spring. Further, the inner ring member is usually made of metal, but there is also a torque limiter made of resin (for example, see Patent Document 2).

Japanese Patent Laid-Open No. 10-110739 JP 2012-97798 A

  However, the torque limiter using a metal inner ring member is usually made of an iron-based sintered alloy, so the cost is high and a certain thickness is required for molding. Is difficult. On the other hand, in a torque limiter using a resin inner ring member, it is necessary to use a grade resin in which a large amount of carbon (carbon fiber) is added to the PPS resin in order to maintain wear resistance, leading to an increase in cost.

  Therefore, the applicant of the present invention presses metal to form an inner ring member, provides a coil spring so as to generate a frictional force with the outer surface of the inner ring member, provides an outer ring member on the outer side of the inner ring member, A torque limiter that locks the end of the coil spring on the peripheral surface and supports the inner ring member was developed, and a patent application was filed as Japanese Patent Application No. 2013-12813. This torque limiter is inexpensive and can reduce the diameter of the inner ring member, but it also wants to improve wear resistance between the inner ring member and the coil spring to improve durability and reduce torque fluctuations. There is a request.

  An object of the present invention is to provide a torque limiter capable of improving the durability of an inner ring member and further reducing torque fluctuation.

  The invention according to claim 1 of the present invention includes an inner ring member formed by press-molding a metal, a coil spring provided so as to generate a frictional force between an outer surface of the inner ring member, and an outer surface of the inner ring member. A linear fluorine grease having a kinematic viscosity that lubricates a contact surface between the inner ring member and the inner ring member. And an outer ring member to be supported.

  The invention according to claim 2 of the present invention is the invention of claim 1, wherein the inner ring member has a two-stage throttle shape in which the outer diameter of the front stage is smaller than the outer diameter of the rear stage, and the end of the rear stage has a trumpet shape. The outer ring member is configured to support the front stage part and the rear stage part of the two-stage throttle shape of the inner ring member on the inner peripheral surface, and to be fitted to a trumpet-shaped maximum diameter part of the inner ring member. A fitting claw for supporting the member is provided.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the coil spring is formed by winding a piano wire and performing barrel polishing after heat treatment.

  According to the present invention, since the linear fluorine grease having a kinematic viscosity that lubricates the contact surface between the outer surface of the inner ring member and the coil spring is used, the wear resistance between the inner ring member and the coil spring can be improved. The durability of can be improved.

  The outer ring member supports the front and rear stages of the inner ring member in the two-stage throttle shape on the inner peripheral surface and is fitted with the trumpet-shaped maximum diameter portion of the inner ring member so that the inner ring member is fitted to the inner peripheral surface of the outer ring member. Since it can support in two places, an inner ring member can be supported stably and a shield member becomes unnecessary. Furthermore, since the coil spring is formed by winding a piano wire and is barrel-polished after the heat treatment, the torque fluctuation can be reduced.

Sectional drawing of the torque limiter which concerns on embodiment of this invention. The left view of the torque limiter which concerns on embodiment of this invention. The right view of the torque limiter which concerns on embodiment of this invention. The perspective view of the inner ring member of the torque limiter concerning the embodiment of the present invention. The perspective view of the state which made the inner ring member of the torque limiter concerning the embodiment of the present invention fit to the outer ring member. The graph which shows the relationship between durability of the inner ring member which used lubricating oil as a parameter, and base oil kinematic viscosity of lubricating oil. The graph which shows the relationship between the torque value which arises in an inner ring member with a coil spring, and the number of cycles of use.

  Embodiments of the present invention will be described below. FIG. 1 is a cross-sectional view of a torque limiter according to an embodiment of the present invention. In FIG. 1, the torque limiter according to the embodiment of the present invention includes an inner ring member 11, a coil spring 12, and an outer ring member 13. The inner ring member 11 is formed by press-molding metal into a two-stage drawn shape in which the outer diameter of the front stage part 14 is smaller than the outer diameter of the rear stage part 15. Moreover, the edge part of the back | latter stage part 15 is formed in the trumpet shape, and has the trumpet-shaped part 16 extended in the trumpet shape.

  Further, the front stage part 14 and the rear stage part 15 of the inner ring member 11 are formed in a cylindrical shape, and have a through hole 17 for allowing a shaft (not shown) to pass therethrough and an engagement hole 18 for engaging with an engagement piece of the shaft. Yes. When the shaft is inserted into the through hole 17, the engagement piece of the shaft is engaged with the engagement hole 18, and the rotation of the shaft is transmitted to the inner ring member 11. The coil spring 12 is provided so as to generate a frictional force with the outer surface of the inner ring member 11. That is, the inner ring member 11 is provided in contact with the outer surface of the front stage portion 14 having a small outer diameter, and the end portion of the coil spring 12 is locked to the outer ring member 13 by the locking portion 19 on the inner peripheral surface of the outer ring member 13.

  Lubricating oil for lubricating the contact surface is applied to the contact surface between the outer surface of the inner ring member 11 and the coil spring 12. This lubricating oil is a linear fluorine grease having a kinematic viscosity of a predetermined value or less, thereby improving the wear resistance between the inner ring member 11 and the coil spring 12 and improving the durability of the inner ring member. The wear resistance of the inner ring member 11 by the lubricating oil will be described later. Further, the coil spring 12 is formed by winding a piano wire, and is formed by barrel polishing after heat treatment. Thereby, the torque fluctuation generated in the inner ring member 11 by the coil spring 12 is reduced. The reduction in torque fluctuation generated in the inner ring member 11 by the coil spring 12 will be described later.

  The outer ring member 13 is provided on the outer side of the inner ring member 11 so as to cover the coil spring 12, and as described above, the end portion of the coil spring 12 is locked by the locking portion 19 on the inner peripheral surface of the outer ring member 13. Further, the inner peripheral surface of the outer ring member 13 and a part of the front step portion 14 of the inner ring member 11 come into contact with each other to form the first support surface 20, and the inner peripheral surface of the outer ring member 13 and a part of the rear step portion 15 of the inner ring member 11 Becomes the second support surface 21 in contact with each other. As a result, the outer ring member 13 supports the inner ring member 11 at two locations of the first support surface 20 and the second support surface 21, and the outer ring member 13 can stably support the inner ring member 11.

  Further, the outer ring member 13 has a fitting claw 22 that fits the largest diameter portion of the trumpet-shaped portion 16 of the inner ring member 11 and supports the inner ring member 11. Thus, since the maximum diameter portion of the trumpet-shaped portion 16 of the inner ring member 11 is supported on the outer ring member 13 by the fitting claws 22, no shield member is required.

  Further, the outer ring member 13 is provided with a fixing portion 23 for fixing the outer ring member 13, and this fixing portion 23 is a device to which a torque limiter is attached, for example, a paper feed mechanism portion of a printer or a copying machine. To be fixed to. As a result, the outer ring member 13 is fixed, and the inner ring member 11 penetrating the shaft engages with the coil spring 12 to transmit and block torque.

  When the rotation of the shaft engaged with the inner ring member 11 is equal to or less than a predetermined value, the coil spring 12 locked to the locking portion 19 on the inner peripheral surface of the outer ring member 13 is between the outer surface of the inner ring member 11. Generates frictional force to transmit shaft torque. On the other hand, when the rotation of the shaft is an excessive torque exceeding a predetermined value, the coil spring 12 slips between the outer surface of the inner ring member 11 and interrupts the transmission of the excessive torque.

  FIG. 2 is a left side view of the torque limiter according to the embodiment of the present invention. As shown in FIG. 2, a fixing portion 23 for fixing the outer ring member 13 is provided on the left side surface portion of the torque limiter according to the embodiment of the present invention. The fixing portion 23 is mounted with a torque limiter. Connected and fixed to the device.

  FIG. 3 is a right side view of the torque limiter according to the embodiment of the present invention. As shown in FIG. 3, the right side surface portion of the torque limiter according to the embodiment of the present invention has an engagement hole 18 for locking the shaft inserted into the through hole 17, and the shaft is a through hole. When inserted into the shaft 17, the engaging piece of the shaft engages with the engaging hole 18, and the rotation of the shaft is transmitted to the inner ring member 11.

  Next, FIG. 4 is a perspective view of the inner ring member of the torque limiter according to the embodiment of the present invention. As described above, in the embodiment of the present invention, the inner ring member 11 is formed by press-molding metal. By using the press-molded metal inner ring member 11, the part can be thinned to reduce the diameter and the price.

  On the other hand, in order to press form a metal, a metal (soft metal) suitable for press forming is desirable. Therefore, in the embodiment of the present invention, for example, an SPCC material (inexpensive iron material) is used. Considering the durability of the inner ring member 11, it is necessary to improve the wear resistance and slidability. Therefore, barrel polishing is performed after the nitriding treatment (surface hardening treatment) to remove the oxidized layer on the surface and the durability is improved. Improve sexiness.

  Furthermore, in the embodiment of the present invention, in order to improve durability, the inner ring member 11 is shaped in two stages of the front stage part 14 and the rear stage part 15 so that the inner ring member 11 is not subjected to a radial load or an unintended uneven load. The shape of the diaphragm is such that the torque limiter performance is not impaired as a support structure at two locations by the outer ring member 13.

  In addition, a trumpet-shaped portion 16 is formed that widens the end portion of the rear-stage portion 15 in a trumpet shape, and a notch portion 24 is provided in the maximum diameter portion of the trumpet-shaped portion 16 so that the outer ring member 13 can be easily fitted. The shield member can be omitted.

  FIG. 5 is a perspective view of a state in which the inner ring member 11 of the torque limiter according to the embodiment of the present invention is fitted to the outer ring member 13. In order to fit the inner ring member 11 to the outer ring member 13, the notch portion 24 of the inner ring member 11 and the fitting claw 22 of the outer ring member 13 are aligned, the inner ring member 11 is inserted into the outer ring member 13, and then The inner ring member 11 is rotated in either the clockwise direction or the counterclockwise direction, and the inner ring member 11 and the outer ring member 13 are locked by the fitting claws 22. Thereby, it is possible to prevent the inner ring member 11 from falling off the outer ring member 13. Note that the notch 24 is not necessarily provided. If the outer ring member 13 itself is flexible, when the inner ring member 11 is fitted to the outer ring member 13, the maximum diameter portion of the trumpet-shaped portion 16 of the inner ring member 11 is caused by the bending of the outer ring member 13. This is because it can be fitted to the inner peripheral surface of the member 13.

  Next, the wear resistance of the inner ring member 11 with lubricating oil will be described. FIG. 6 is a graph showing the relationship between the durability of the inner ring member 11 and the base oil kinematic viscosity of the lubricating oil with the lubricating oil as a parameter. The vertical axis represents the durability (number of rotations) of the inner ring member 11, and the horizontal axis represents the base oil kinematic viscosity of the lubricating oil when the temperature is 40 ° C. The durability (number of rotations) of the inner ring member 11 on the vertical axis indicates the number of rotations of the inner ring member 11 that can maintain a usable state as the inner ring member 11.

  The black diamonds in FIG. 6 are data in the case of linear fluorine grease as the base oil of the lubricating oil, the point A1 is the data when the base oil kinematic viscosity of the linear fluorine grease is 25 cst (40 ° C.), and the point A2 Is the data when the base oil kinematic viscosity of the linear fluorine grease is 90 cst (40 ° C), point A3 is the data when the base oil kinematic viscosity of the linear fluorine grease is 100 cst (40 ° C), and the point A4 is straight It is data when the base oil kinematic viscosity of the chain fluorine grease is 140 cst (40 ° C.). On the other hand, the black circles in FIG. 6 are data in the case of mixed fluorine grease of linear fluorine grease and side chain fluorine grease as the base oil of the lubricating oil, and point B1 indicates that the base oil kinematic viscosity of the mixed fluorine grease is 45 cst. Data at (40 ° C.), point B2 is data when the base oil kinematic viscosity of the mixed fluorine grease is 200 cst (40 ° C.).

  When the base oil kinematic viscosity of the linear fluorine grease is 25 cst (40 ° C.), the durability (number of rotations) of the inner ring member 11 is 15.5 million times (A1 point), and the base oil kinematic viscosity of the linear fluorine grease is 90 cst. The durability (the number of rotations) of the inner ring member 11 at (40 ° C.) is 11.28 million times (A2 point), and the durability of the inner ring member 11 when the base oil kinematic viscosity of the linear fluorine grease is 100 cst (40 ° C.). The durability (number of rotations) is 5 million times (A3 points), and the durability (number of rotations) of the inner ring member 11 is 3 million times (A4 points) when the base oil kinematic viscosity of the linear fluorine grease is 140 cst (40 ° C). The durability (number of rotations) of the inner ring member 11 when the base oil kinematic viscosity of the mixed fluorine grease is 45 cst (40 ° C.) is 8 million times (point B1), and the base oil kinematic viscosity of the mixed fluorine grease is 200 cst. The durability (number of rotations) of the inner ring member 11 at (40 ° C) is 2.4 million times (B2 point) A.

  In both cases of linear fluorine grease and mixed fluorine grease, the durability (number of rotations) of the inner ring member 11 improves as the base oil kinematic viscosity decreases. Further, when compared with the linear fluorine grease and the mixed fluorine grease, the durability (number of rotations) of the linear fluorine grease is improved. Therefore, in the embodiment of the present invention, linear fluorine grease having a base oil kinematic viscosity of a predetermined value or less is used. Specifically, linear fluorine grease having a base oil kinematic viscosity of 90 cst or less is used. Preferably, linear fluorine grease having a base oil kinematic viscosity of 25 cst (40 ° C.) is used.

  Next, the reduction in torque fluctuation generated in the inner ring member 11 by the coil spring 12 will be described. FIG. 7 is a graph showing the relationship between the torque value generated in the inner ring member 11 by the coil spring 12 and the number of cycles used, and FIG. 7A shows the case of the coil spring according to the embodiment of the present invention in which barrel polishing is performed after heat treatment. FIG. 7B is a graph for a conventional coil spring that is not subjected to barrel polishing after heat treatment.

  In FIG. 7A, black diamonds are data of static torque values that are torques at which movement starts from a stationary state, and black squares are data of dynamic torque values that are torques when moving. A curve S11 is a curve connecting static torque values, and a curve S12 is a curve connecting dynamic torque values. When the coil spring 12 according to the embodiment of the present invention subjected to barrel polishing after the heat treatment is used, as can be seen from FIG. 7A, either the static torque value or the dynamic torque value generated in the inner ring member 11 through 500,000 cycles. There is no reduction.

  In FIG. 7B, black diamonds are data of static torque values, and black squares are data of dynamic torque values. A curve S21 is a curve connecting static torque values, and a curve S22 is a curve connecting dynamic torque values. When the conventional coil spring 12 not subjected to barrel polishing after the heat treatment is used, as can be seen from FIG. 7B, both the static torque value and the dynamic torque value generated in the inner ring member 11 are reduced when exceeding 400,000 cycles. You can see that

  Therefore, in the embodiment of the present invention, the coil spring 12 formed by winding a piano wire and heat-treated is subjected to barrel polishing after the heat treatment. Here, the molded product formed by winding the piano wire is heat-treated (tempered) in order to stabilize the shape of the coil spring and reduce the initial torque fluctuation, and in that case, an oxide scale is generated. In the embodiment of the present invention, the barrel polishing is performed in order to remove oxide scale generated by the heat treatment. By removing the oxidized scale, the torque fluctuation generated in the inner ring member 11 by the coil spring 12 can be reduced.

  In the above description, the inner ring member 11 is formed by press-molding metal into a two-stage drawn shape in which the outer diameter of the front stage 14 is smaller than the outer diameter of the rear stage 15, and the end of the rear stage 15 is a trumpet shape. The trumpet-shaped portion 16 is formed to have a kinematic viscosity of not more than a predetermined value even for a torque limiter including the inner ring member 11 that does not have the trumpet-shaped portion 16 instead of the two-stage throttle shape. The durability of the inner ring member can be improved by applying chain-based fluorine grease, and torque fluctuation can be reduced by using the coil spring 12 that has been subjected to barrel polishing after heat treatment.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 11 ... Inner ring member, 12 ... Coil spring, 13 ... Outer ring member, 14 ... Front stage part, 15 ... Rear stage part, 16 ... Trumpet-like part, 17 ... Through-hole, 18 ... Engagement hole, 19 ... Locking part, 20th DESCRIPTION OF SYMBOLS 1 Support surface, 21 ... 2nd support surface, 22 ... Fitting nail | claw, 23 ... Fixed part, 24 ... Notch part

The invention according to claim 1 of the present invention is
Locking an inner ring member formed of "metal, and a coil spring which is provided to produce a frictional force between the outer surface of the inner ring member, an end portion of the coil spring in the peripheral surface provided on the outside of the inner ring member And a torque limiter comprising an outer ring member that supports the inner ring member,
The inner ring member has a two-stage cylindrical shape in which the outer diameter of the front stage is smaller than the outer diameter of the rear stage, and the end of the rear stage is formed in a trumpet shape .
The coil spring is provided in contact with the outer surface of the front portion of the inner ring member, and the contact surface is lubricated by linear fluorine grease having a base oil kinematic viscosity of 25 cst or more and 90 cst or less at 40 ° C. And
The outer ring member has a fitting claw that supports the inner ring member by supporting the front and rear stages of the inner ring member on an inner circumferential surface and fitting the trumpet-shaped maximum diameter portion of the inner ring member. I have it. ''
The torque limiter is characterized by this .

The invention according to claim 2 of the present invention is the torque limiter according to claim 1, wherein “the coil spring is formed of a spiral piano wire”. The invention according to claim 3 of the present invention is the torque limiter according to claim 1 or 2, wherein the inner ring member has a through-hole through which the shaft passes and an engagement hole for locking the shaft. "It is doing".

The invention according to claim 4 of the present invention is the method of manufacturing a torque limiter according to any one of claims 1 to 3, wherein the inner ring member is formed by press-molding a metal. To do. The invention according to claim 5 is the method of manufacturing a torque limiter according to claim 2 or claim 3, wherein “the inner ring member is formed by press-molding a metal and formed by winding a piano wire. The coil spring is subjected to barrel polishing after heat treatment, and is provided in contact with the outer surface of the front stage portion of the inner ring member ”.

According to the present invention, the contact surface between the outer surface of the inner ring member and the coil spring is lubricated with linear fluorine grease having a base oil kinematic viscosity of 25 cst or more and 90 cst or less at 40 ° C. Even if it consists of the metal formed by shaping | molding etc., the abrasion resistance of an inner ring member and a coil spring can be improved, and durability of an inner ring member can be improved.
The inner ring member has a two-stage cylindrical shape in which the outer diameter of the front stage is smaller than the outer diameter of the rear stage, and the end of the rear stage is formed in a trumpet shape. The outer ring member supports the two-stage cylindrical front and rear stages of the inner ring member on the inner circumferential surface thereof, and is fitted to the trumpet-shaped maximum diameter portion of the inner ring member so that the inner ring member is fitted to the inner circumference of the outer ring member. Since it can be supported at two places on the surface, the inner ring member can be stably supported, and a shield member is unnecessary .

Furthermore, according to the manufacturing method of claim 4 of the present invention, a two-stage cylindrical inner ring member whose outer diameter of the front stage is smaller than the outer diameter of the rear stage can be easily and inexpensively formed by press molding of the two-stage drawing. Can be formed. According to the manufacturing method of the fifth aspect, since the coil spring is formed by winding a piano wire and is subjected to barrel polishing after the heat treatment, torque fluctuation can be reduced.

Embodiments of the present invention will be described below. FIG. 1 is a cross-sectional view of a torque limiter according to an embodiment of the present invention. In FIG. 1, the torque limiter according to the embodiment of the present invention includes an inner ring member 11, a coil spring 12, and an outer ring member 13. The inner ring member 11 is formed by pressing a metal into a two-stage drawn shape in which the outer diameter of the front stage part 14 is smaller than the outer diameter of the rear stage part 15 and has a two-stage cylindrical shape . Moreover, the edge part of the back | latter stage part 15 is formed in the trumpet shape, and has the trumpet-shaped part 16 extended in the trumpet shape.

Lubricating oil for lubricating the contact surface is applied to the contact surface between the outer surface of the inner ring member 11 and the coil spring 12. This lubricating oil is a linear fluorine grease having a base oil kinematic viscosity of a predetermined value or less, thereby improving the wear resistance between the inner ring member 11 and the coil spring 12 and improving the durability of the inner ring member. Yes. The wear resistance of the inner ring member 11 by the lubricating oil will be described later. The coil spring 12 is formed in a spiral shape by winding a piano wire, and is barrel-polished after heat treatment. Thereby, the torque fluctuation generated in the inner ring member 11 by the coil spring 12 is reduced. The reduction in torque fluctuation generated in the inner ring member 11 by the coil spring 12 will be described later.

When the rotational torque of the shaft engaged with the inner ring member 11 is equal to or less than a predetermined value, the coil spring 12 locked to the locking portion 19 on the inner peripheral surface of the outer ring member 13 is between the outer surface of the inner ring member 11. Generates frictional force to transmit shaft torque. On the other hand, when the rotational torque of the shaft is an excessive torque exceeding a predetermined value, the coil spring 12 slips between the outer surface of the inner ring member 11 and interrupts the transmission of the excessive torque.

In both cases of linear fluorine grease and mixed fluorine grease, the durability (number of rotations) of the inner ring member 11 improves as the base oil kinematic viscosity decreases. Further, when compared with the linear fluorine grease and the mixed fluorine grease, the durability (number of rotations) of the linear fluorine grease is improved. Therefore, in the embodiment of the present invention, linear fluorine grease having a base oil kinematic viscosity of a predetermined value or less is used. Specifically, linear fluorine grease having a base oil kinematic viscosity of 90 cst or less is used. Preferably , linear fluorine grease having a base oil kinematic viscosity of 25 cst (40 ° C.) is used.

Claims (3)

An inner ring member formed by pressing metal,
A coil spring provided to generate a frictional force with the outer surface of the inner ring member;
A linear fluorine grease whose kinematic viscosity for lubricating the contact surface between the outer surface of the inner ring member and the coil spring is a predetermined value or less;
A torque limiter, comprising: an outer ring member that is provided outside the inner ring member and that locks an end of the coil spring on an inner peripheral surface and supports the inner ring member.   The inner ring member has a two-stage throttle shape in which the outer diameter of the front stage part is smaller than the outer diameter of the rear stage part, and the end part of the rear stage part is formed in a trumpet shape. 2. A fitting claw that supports the inner ring member by supporting the front-stage part and the rear-stage part of a stepped throttle shape and fitting with a trumpet-shaped maximum diameter portion of the inner ring member. The described torque limiter.   The torque limiter according to claim 1 or 2, wherein the coil spring is formed by winding a piano wire and performing barrel polishing after heat treatment.

Images